Avi Loeb Medium

An image of 3I/ATLAS, taken on November 26, 2025 by the Gemini Multi-Object Spectrograph (GMOS) on Gemini North on Maunakea in Hawaii, an observatory funded by the U.S. National Science Foundation (NSF) and operated by NSF’s NOIRLab. This image is composed of exposures taken through four filters — blue, green, orange, and red. The exposures were centered on 3I/ATLAS while the background stars appear as streaks. The teardrop shape of the green glowing halo around 3I/ATLAS features an anti-tail in the direction of the Sun, towards the lower left. (Image Credit: International Gemini Observatory/NOIRLab/NSF/AURA/B. Bolin)Exactly four weeks after its perihelion, on November 26, 2025, the interstellar object 3I/ATLAS was imaged by the Gemini Multi-Object Spectrograph (GMOS) on the 8.1-meter telescope Gemini North at Maunakea, Hawaii, an observatory funded by the U.S. National Science Foundation (NSF) and operated by NOIRLab. The post-perihelion image, posted here, combines exposures through four filters — blue, green, orange, and red, and its peak brightness is centered on the nucleus 3I/ATLAS. The color of the glowing halo appears green, possibly as a result diatomic carbon (C2) molecules which emit green light. A pre-perihelion image, posted here on September 4, 2025, from the twin 8.1-meter telescope Gemini South in Chile, displayed a red color of the glow around 3I/ATLAS. The change in colors from red to green means that the molecular composition of the plume of gas shed by 3I/ATLAS had changed near the Sun. *** Is 3I/ATLAS Related to the longest-duration gamma-ray burst GRB 250702b? Before my routine jog at sunrise, I was asked about an unusual coincidence reported on video here, between the arrival direction of 3I/ATLAS when it was discovered on July 1, 2025 (RA=272 degrees and Dec= -19 degrees) and the arrival direction of the longest ever (lasting 25,000 seconds or about 7 hours) gamma-ray burst GRB 250702b — which was discovered on July 2, 2025 (RA=285 degrees and Dec=-8 degrees) and reported here. The angular separation between the two directions was 17 degrees on July 2, 2025, corresponding to a chance alignment probability of 0.02. However, the date of July 2, 2025 is not particularly significant since we just happened to discover 3I/ATLAS around that time but 3I/ATLAS was moving through the Oort Cloud of the Solar system for 8,000 years before that. Since there are several hundred gamma-ray bursts per year spread evenly across the entire sky, a chance coincidence of 0.02 between one of them and 3I/ATLAS is not unusual. Such a coincidence is expected to occur many times over a period as long as 8,000 years even if the ultra-long duration of GRB 250702b appears only in a small fraction of the burst population. In fact, we know of another gamma-ray burst that lasted about 4–7 hours on December 9, 2011, GRB 111209A, as reported here. This was followed by a supernova reported here and is definitely the result of an exploding star at a luminosity distance of 13.7 billion light years. This means that an ultra-long duration burst occurs as a result of a random cosmic event once per 14 years, during which there is a total of about 4,000 bursts. A 7-hour gamma-ray burst should therefore coincide to within 17 degrees of the arrival direction of 3I/ATLAS once per 670 years. Altogether, there had been a dozen such coincidences while 3I/ATLAS was traveling inside the Solar system over the past 8,000 years and the latest one happened to occur this year. But even during 2025 alone, there had been about 6 gamma-ray bursts of normal duration that coincided to within 17 degrees of the arrival direction of 3I/ATLAS. *** A Piece of Art This morning, I also received the following poem and accompanying image from the poet Alan Wagstaff in Auckland, New Zealand: DUMBFOUNDED Professors were dumbfounded when the strangers’ craft first docked. They gawped in awe — astounded, then fell dumbstruck; some were shocked. Two hundred miles above Mount Locke the stealthy star-craft hung. Although it looked like stellar rock, it purred a Cosmic tongue. Confusion spread and seemed to waft around the reeling globe. We ceded dominance. Earth doffed its cap to Avi Loeb. A telescope is better than mere eyesight or mere ears. A man sees what he thinks he can, and hears the slant he hears. Alan Wagstaff ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

Image of 3I/ATLAS on November 24, 2025 at 1:58 UTC from a 12-inch telescope in Namibia. North is to the right and the sunward direction is towards the upper left. The field of view is 75 by 100 arcminutes, corresponding to 6.6 by 8.8 million kilometers. The blue glow at the bottom right corner of the image is caused by the triple star system Eta Virginis. (Image Credit: Gerald Rhemann and Michael Jäger)Below is a Q&A list that combines questions from various reporters about the interstellar object 3I/ATLAS, a week before its closest approach to Earth: Q: How can a space probe hypothetically resemble a comet? Break it down for us like a 5th grader. A: A comet is identified as an object that sheds dust and gas as a result of the illumination of pockets of ice on its surface by sunlight. While shedding mass in a preferred direction, it recoils in the opposite direction similarly to a rocket. This gives rise to a non-gravitational acceleration. A spacecraft could also collect ice and dust on its surface as a result of its motion through dense gas clouds in interstellar space. In addition, it could gain a non-gravitational acceleration as a result of a propulsion system. Given these features, it may resemble a comet in unresolved images like the ones we have of 3I/ATLAS. However, a spacecraft could also display artificial lights, release excess heat from its engine or maneuver in unusual ways. Q: Why are some scientists pushing back against any discussion on the conjecture that the anomalies of an interstellar object might be technological signatures? A: The foundation of science is based on the humility to learn, not the arrogance of expertise. When comet experts argued that the interstellar object 3I/ ATLAS must be a familiar water-rich comet as soon as it was discovered in July, they behaved like artificial intelligence systems: only able to reflect the data sets they were trained on. For decades, the data set that established comet expertise largely comprised icy rocks in the solar system. My counterpoint is simple: humanity launched technological objects into space, so we must conclude that alien life forms could do the same. This possibility must be added to the training data set of comet experts when studying interstellar objects. To illustrate why, consider the following: on 2 January 2025, the Minor Planet Center — officiated by the International Astronomical Union to catalogue space objects — identified a ‘near-Earth asteroid’. A day later, the officials realized that this ‘asteroid’ was following the same trajectory of the Tesla Roadster launched by Elon Musk’s SpaceX in 2018. They immediately removed the object from their asteroid catalogue, realizing that it was not in fact a rock but a car. Musk, statistically, is not the most accomplished space entrepreneur in the Milky Way over the past 13.8 billion years. There are about a hundred billion stars with similar properties to the Sun in the Milky Way; roughly a tenth of them host a habitable Earth-size planet. If you roll the dice on billions of Earth-sun analogues, surely you would — or at least could — find other space entrepreneurs on some exoplanets? There is no reason why 3I/ATLAS is not a ship launched from one of them. Most stars are billions of years older than the Sun. Our Voyager spacecraft, with its 1970s technology, can reach the opposite side of the galaxy over the course of a billion years. This implies that there has been plenty of time for interstellar artefacts, potentially more advanced than Voyager or the Tesla Roadster, to reach our solar system from interstellar space. But would comet experts recognize these visitors as technological artefacts if their training data set includes only icy rocks? I do not believe so. Q: Can you summarize the main anomalies of 3I/ATLAS? Let’s look at the evidence. I have identified the following main anomalies of 3I/ATLAS: Its trajectory opposite to the direction of motion of the planets is aligned to within five degrees with the ecliptic plane of the planets around the Sun, with a likelihood of 0.2 percent. This suggests that it may have been designed to do this. It arrived from a direction coincident with the enigmatic “Wow! Signal” to within 9 degrees. The chance of that happening at random is 0.6 percent. Before and after perihelion, it displayed a sunward jet (anti- tail) that is not an optical illusion from geometric perspective, unlike familiar comets. This might be a technological signature. Its arrival time was fine-tuned to bring it within tens of millions of kilometers from Mars, Venus and Jupiter and be unobservable from Earth at perihelion (when an object is closest to the Sun), with a likelihood of 0.005 percent. The forecasted perijove distance of 3I/ATLAS during its encounter with Jupiter on March 16, 2026 is 53.6 million kilometers, nearly identical to Jupiter’s Hill radius, 53.5 million kilometers. This rare coincidence might mean that 3I/ATLAS intends to release technological devices as artificial satellites of Jupiter, potentially at Jupiter’s Lagrange points — where orbital corrections and fuel requirements are minimal. The nucleus of 3I/ATLAS is several orders of magnitude times more massive than 1I/`Oumuamua and 2I/Borisov, while moving faster than both. There is not enough rocky material in interstellar space to deliver a rock of this mass once per decade to the inner solar system. This suggests that 3I/ATLAS may have targeted the inner solar system rather than was drawn at random from the reservoir of interstellar rocks. Its gas plume contains much more nickel than iron (as found in industrially produced nickel alloys) and a nickel to cyanide ratio that is orders of magnitude larger than that of all known comets, with a likelihood below 1 percent. This may be a signature of industrial production of its surface material. It exhibits jets in the direction of the sun and opposite to it, which requires an unreasonably large surface area in order to absorb enough sunlight to sublimate enough ice to feed the mass flux of these jets. Perhaps the jets originate from technological thrusters. Near perihelion it exhibited non-gravitational acceleration. Perhaps this acceleration was produced by an engine. Its tightly collimated jets maintain orientation across a million kilometers in multiple directions relative to the sun. This might imply that they are used for navigation or associated with the release of mini probes from a mothership. Q: Why should science consider the technological origin of interstellar objects? A: If 3I/ATLAS is technological, it could pose a threat to humanity. We do not have a response protocol for alien technology, but after the first encounter — as long as we survive it — there will be political will to invest trillions of dollars in a warning system of interceptors that take close-up photos of anomalous interstellar objects. 3I/ATLAS is expected to arrive closest to Earth in a week, on December 19, 2025. Let us hope that we will not get unwanted gifts for the holidays. In ignoring these anomalies, comet experts miss two important opportunities. First, science needs to be viewed as a continuous process rather than as a finished product. Collecting evidence is a learning experience akin to the work of a detective. It sometimes unravels a sobering truth that was not anticipated, since nature is more imaginative than we are. This was certainly the case when quantum mechanics was discovered a century ago and revealed a physical reality that was counterintuitive to Albert Einstein’s findings. Despite lessons from history, present-day scientists minimize the risk to their reputation by not sharing error-corrections from data and conversing with the public only once they know the final answer. In this risk-averse intellectual climate, they inform the public of their final findings in press conferences, where they behave like lecturers in the classroom. The audience is made aware of what it needs to know. By minimizing the risk to their reputation, scientists promote the impression that science is an occupation of the intellectual elite. The truth is that the mainstream of science is routinely wrong. Albert Einstein argued between 1935 and 1940 that black holes or gravitational waves do not exist. The popular idea of supersymmetry was ruled out by CERN’s Large Hadron Collider. In addition, after four decades of occupying center stage in mainstream theoretical physics, string theory is no closer to making unique predictions that can be tested experimentally. Science is a work in progress. Anomalies offer a multitude of interpretations that are tested by new data that can rule out all but one of them. Second, the mainstream defined the search for microbes as the highest priority in the 2020 U.S. Decadal Survey of Astronomy and Astrophysics, converging on the allocation of more than 10 billion dollars to the Habitable World Observatory and sidelining the search for technological signatures. Even if microbes are far more abundant on exoplanets, it might be easier to identify technological signatures. It therefore makes most sense to hedge our bets and invest billions of dollars in the simultaneous search for both technological and primitive life forms. The public is much more passionate about the search for aliens than the search for microbes. Taxpayers fund science and scientists should not sideline the public’s interest when defining research priorities. I receive hundreds of emails from fans every day and many parents write that their children wish to become scientists after seeing me speak in podcasts or on television. Q: You dubbed the perihelion of 3I/ATLAS as a probable ‘black swan’ event. What are your thoughts on its closest flyby to Earth? A: 3I/ATLAS will pass closest to Earth on December 19, 2025. Fortunately, this date coincides with a new moon when the view of the sky will not be contaminated by moonlight, making it an ideal observing night for Earth-based telescopes. My hope is that we will gain new insights into the nature of 3I/ATLAS at that time thanks to data from hundreds of observatories, including the Hubble and Webb space telescopes. In particular, spectrographs on large telescopes can measure the speed and composition of the outflowing material in the jets of 3I/ATLAS. If these jets originate from pockets of ice on the surface of a rock, then their thermal speed would be smaller than a few hundreds of meters per second. This speed is much smaller than expected from technological thrusters. Q: Can we possibly deduce a connection between the surge in solar flares and 3I/ATLAS? Would that be speculative sci-fi? A: It is unlikely that the surge in solar flares is connected to 3I/ATLAS. However, our imagination is mostly limited by the technologies we possess. Q: What is the best evidence so far that suggests we are probably not alone in the universe? A: It is arrogant to believe that we are alone in the Milky-Way because it contains 100 billion stars. Since we emerged from a soup of chemicals which is common on habitable Earth-mass planets, common sense suggests that the galaxy is teaming with life. Q: What is the current status of the study on the interstellar meteor IM1? A: We are currently analyzing the chemical and isotopic composition of the materials collected from the fireball site of the interstellar meteor IM1, and have preliminary evidence for a composition that originated outside the solar system. More details about our results will be made public in spring 2026. Q: Are you into comics? If so, which ones are your favorite heroes/villains, etc.? A: No, I am not. Q: And why? A: I do not have time for that. I focus on studying physical reality with the best scientific tools that I have access to. Q: Have you watched Stranger Things? or similar supernatural / sci-fi series? Your remarks. A: No, I enjoy science fact, not science fiction. Q: Growing up, what fascinated you to pick up astronomy? A: It was forced upon me by circumstances. In 1988 I was offered a 5-year fellowship at the Institute for Advanced Study in Princeton — where Albert Einstein was faculty three decades earlier, under the condition that I will work on astrophysics. Q: Why is the new frontier of interstellar objects exciting? A: Remarkably, interstellar objects offer a new opportunity for both the search for primitive and technological lifeforms. We can land on an interstellar rock and return a sample of it to Earth. The returned sample may reveal the building blocks of life from another star. But if the interstellar object happens to be a technological artefact, our learning opportunities would be far greater. The fundamental question after landing on a spacecraft with buttons on its surface would be whether to press any of them. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

An image of 3I/Atlas on December 9, 2025 (left panel) shows a sunward jet (right panel, Larson-Sekanina gradient filter) that was also apparent in the Hubble Space Telescope image from November 30, 2025. (Image Credit: Toni Scarmato)There is no doubt that we can learn something new from the interstellar object 3I/ATLAS, irrespective of whether it is an icy rock or a spacecraft. The only obstacle to learning is comet experts who display the arrogance of expertise. How can anyone claim to be an expert of interstellar objects when the sample size includes only two previously known examples, 1I/`Oumuamua and 2I/Borisov and when 3I/ATLAS displays 13 anomalies relative to these two (as listed here)? The anti-tail of 3I/ATLAS appears in our highest-resolution images from the Hubble Space Telescope, one obtained before (here) and the second after (here) perihelion. The orientation of the anti-tail flipped relative to the direction of motion at perihelion and is definitely not a matter of perspective as is the case for some comets. What is the physics of the anti-tail of 3I/ATLAS? Micrometer-scale, refractory dust particles would have been swept away from the Sun by the solar radiation and wind. The anti-tail must therefore contain something else. To account for its properties, I wrote three papers so far explaining it as being made of fragments of ice that evaporate before turning around (here and here) or large objects that are not affected much by the solar radiation or wind (here). Why are comet experts and NASA officials so reluctant in displaying curiosity about the anti-tail or other anomalies of 3I/ATLAS? To gain further insight, let us consider another news story that garnered attention over the past week. Two major experiments were motivated by anomalies in past data and searched for ghost neutrinos that do not couple to matter. They both failed to find these sterile neutrinos, as reported in two Nature magazine papers (here and here). The Standard Model of particle physics lists three neutrino flavors of the electron, muon and tau types. Quantum-mechanical oscillations allow a neutrino of one flavor to be detected at a later time as a different flavor. Anomalies reported in previous experiments were inconsistent with this three-flavor picture and have motivated the hypothesis that an additional neutrino state exists of a sterile neutrino that does not interact with matter. The anomalous data included oscillations observed by the Liquid Scintillator Neutrino Detector (LSND) experiment and Mini-Booster Neutrino Experiment (MiniBooNE). The first paper (here) from the MicroBooNE used oscillation data from two neutrino beams to exclude a single sterile neutrino interpretation of the LSND and MiniBooNE anomalies at the 95% confidence level. The second paper (here) used tritium beta-decay (electron emission) in the Karlsruhe Tritium Neutrino (KATRIN) experiment, to search for sterile neutrinos. A sterile-neutrino signal would appear as a distortion in the beta-decay energy spectrum, characterized by a discontinuity related to the sterile-neutrino mass. The analysis of the energy spectrum of 36 million tritium beta-decay electrons recorded in 259 measurement days excluded most of the parameter space suggested by previous claims for a sterile neutrino. These experiments cost a total of (20+70)=90 million dollars. But their goal to explain past anomalies was not a waste. Testing potential explanation of anomalies, here in terms of a new ghost particle, is at the foundation of scientific frontiers that attempt to expand our scientific knowledge. Yet, self-declared experts insist that anomalies of interstellar objects like 1I/`Oumuamua or 3I/ATLAS should only be framed in the context of our past knowledge on asteroids or comets. Any discussion that goes beyond these categories is “nonsense on stilts” as phrased here by the dogmatist Chris Lintott, only a few weeks after the interstellar object 3I/ATLAS was discovered and well before we had any detailed data about its properties. By now, I had written 11 papers on 3I/ATLAS (available here). At the end of my first paper (posted here), I included the concluding sentence: “If 3I/ATLAS is a solid object with a physical radius larger than 10 kilometers, then the limited interstellar reservoir of rocky materials would suggest that its trajectory favored a plunging orbit towards the inner Solar system, perhaps by technological design”. As editor of the journal where my paper was submitted, Lintott insisted that I remove this sentence before the paper gets accepted for publication. His insistence motivated me to co-author a full paper on the technological interpretation (accessible here), which was peer-reviewed and accepted for publication in another journal. No dogmatist commented on the anomalies leading to the notion of sterile neutrinos as “nonsense on stilts” even after the effort to validate this notion failed. Why is the idea of a technological origin for interstellar objects far more controversial than the failed idea of sterile neutrinos? In terms of risk management, the search for sterile neutrinos clearly does not hold more promise given the latest experimental data. Moreover, alien technology has more relevance to the future of humanity and hence deserves scientific attention. This was the question I discussed with the president of the Templeton Foundation, Tim Dalrymple, and his daughter, during their visit to my home today, when we pondered over the latest frontiers of science. A genuine curiosity about anomalies is common among science enthusiasts outside academia. Over the past day, I received the following two messages which shed more light on this state of affairs. *** Letter 1: “Dear Professor Avi Loeb, I hope this email finds you well. Please accept my deepest gratitude for the extraordinary work you continue to do. Through your bold ideas, rigorous scientific inquiry, and fearless exploration of the unknown, you have truly opened a new universe of learning — not only for the scientific community but for our entire planet and for generations yet to come. Your willingness to challenge conventional thinking and pursue evidence wherever it may lead has rekindled humanity’s sense of wonder about the cosmos and our place within it. Like millions of others around the world, I am now following the trajectory of the interstellar visitor 3I/ATLAS with bated breath. The coming days, culminating in the critical observational window around December 19th, feel historic. We await with great anticipation whether this mysterious object will make a close approach to Earth — offering us an unprecedented opportunity to study an object from another star system up close — or whether it will continue its silent journey toward Jupiter and the outer solar system. Whatever its path, the mere possibility of such an event reminds us how fragile, precious, and interconnected our perspective of the universe truly is. Your voice has been instrumental in helping us recognize these moments when they arrive. Thank you once again for your inspiration, courage, and dedication to the pursuit of truth. With profound admiration and excitement for what the coming weeks may reveal. 3I/ATLAS On the night of 19 December we stand barefoot on terraces, the city finally silent, our palms open to the sky as if a comet can be held the way a child holds a firefly —  not to trap it, but to believe for a moment you belong to hearts a silver needle sewing inky velvet of space with hope, we wonder if we will never part… Warm regards, Rina Tripathi” Letter 2: “Dear Avi, I honorably think your colleagues fall into four categories, but not all are the same: (1) Jealousy; (2) Extreme jealousy with possible antisemitism operative; (3) A fundamental belief that there’s a close to zero percent chance that an artifact will ever or has ever come through the solar system; and (4) A basic misunderstanding of what you are doing. Mostly you’re looking at the binary discourse comet/asteroid comet/asteroid and saying, “Gang, let’s always include a third category when objects arrive that behave in unfamiliar ways. If we don’t even imagine the possibility, then like 1I/’Oumuamua, we’ll force the comet/asteroid slipper to fit any foot.” Somehow, 1I/’Oumuamua has been rendered a comet in the history books. The truth is that you can offer a natural hypothesis for 1I/’Oumuamua, but the problem is self-evident. The crush of explanations to avoid the possibility of including an artificial object was so emphatic that, “Me thinks the… [self-declared experts] … doth protest too much.” What I think everyone misses, is that you’re not so interested in rocks and comets anymore. You’re interested in first seeing if an object might be something far more interesting. When I go to the beach, and poke around a tide pool, I know that there’s a lot of rocks and sand, but I’m looking for something more interesting. A particle physicist is searching for a new particle. They search the debris from the supercollider for something other than up or down quarks. I don’t see the difference between that wholly accepted search and your search which is criticized. Particle physicists search the familiar data endlessly for an anomaly. Nobody expresses public animosity. And Avi, the few substantial astrophysicists who feel the need to criticize your work reveal a blind spot and something misguided in their fundamental make-up. It’s an admission of conventionality. An interstellar meteor has properties that are curious. You mount an expedition to take a look. And because someone can find a road with trucks, that one data point dismisses your entire endeavor. It’s a search to discredit, not a search for truth. Unless I missed something, we don’t know what 1I/’Oumuamua was, and my own sense is that even an interstellar comet might have been visited by another curious civilization so there could be probes on the surface from long ago. And my new thought is that if an interstellar comet is coming through the solar system, why not use that existing infrastructure to place a variety of sensory on it without having to launch the core infrastructure. Billions of years is a long time and it could be many things we don’t even consider even if it’s a comet also. I am certain of one thing, you are the one scientist going to, “take a look”. Nobody else will find anything more than a marginal (2-sigma) possibility of life from dimethyl sulfide in an exoplanet atmosphere or phosphine in Venus’ atmosphere. I’d be excited to find a prokaryote somewhere, but why are we setting our sights so low? Josh Ravetch Playwright, Los Angeles” ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

An X-ray image of the interstellar object 3I/ATLAS captured by the soft X-ray imaging telescope Xtend onboard the XRISM Observatory of the Japanese Aerospace Exploration Agency (JAXA), displaying a field of view of 3 million kilometers on a side. The image shows a faint emission structure extending out to 400,000 kilometers from 3I/ATLAS. (Image credit: JAXA)The first X-ray detection of the interstellar object 3I/ATLAS was just reported from the soft X-ray imaging telescope Xtend onboard the X-Ray Imaging and Spectroscopy Mission XRISM of the Japanese Aerospace Exploration Agency (JAXA). Xtend consists of an X-ray telescope that focuses incoming X-rays and an X-ray CCD camera that detects the signal and spans a wide field of view of 38.5 arcminutes on a side. The XRISM satellite also includes the instrument Resolve, which performs high-resolution X-ray spectroscopy. The new X-ray image spans a projected square of 3 million kilometers on a side around 3I/ATLAS and shows a faint emission glow extending out to 400,000 kilometers from its nucleus. Before this report, 3I/ATLAS was only detected in the UV, visible, infrared, submillimeter and radio bands. X-ray emission from Solar system comets was first discovered in 1996 around the Comet Hyakutake (as reported here) and was later confirmed in other comets (as discussed here). No X-rays were previously detected from interstellar objects. Given its large mass and extended coma, 3I/ATLAS provided an ideal target for X-ray observations. Trajectory of the interstellar object 3I/ATLAS in Galactic coordinates, superimposed on an all-sky X-ray map from JAXA’s Monitor of All-sky X-ray Image (MAXI) onboard the International Space Station. The inset shows optical (DSS) and X-ray (eROSITA) images with the XRISM field of view overlaid. (Image credit: JAXA/DSS/eROSITA/MAXI).The X-ray satellite XRISM conducted a Target of Opportunity observation of 3I/ATLAS a month after its brightest phase of perihelion on October 29, 2025 when it was hidden behind the Sun from Earth-based satellites. XRISM can only observe the sky at a separation larger than 60 degrees from the Sun, and so its observation of 3I/ATLAS was timed accordingly from 23:20 UTC on November 26 to 20:38 UTC on November 28, 2025, with a total exposure time of 17 hours. 3I/ATLAS drifted slowly across the constellation Virgo during the observation, and so the satellite’s attitude was adjusted 14 times (every three hours) to keep 3I/ATLAS near the center of the field of view of Xtend. The resulting findings were posted here. A preliminary analysis of the images centered on 3I/ATLAS revealed a faint X-ray glow extending over an angular scale of 5 arcminutes, corresponding to a separation of 400,000 kilometers from 3I/ATLAS. This suggests that the glowing X-ray halo is associated with the plume of gas around 3I/ATLAS which was detected by the SPHEREx Space Observatory (here) and the Webb Space Telescope (here) in August 2025. A natural origin for reported signal is X-ray emission by the plume of gas around 3I/ATLAS as it interacts with the solar wind. As the wind’s charged particles exchange charge with the gas cloud particles, they result in X-ray emission. Indeed, the Xtend spectrum shows excess emission components associated with carbon, nitrogen, and oxygen beyond the background emission from the Milky-Way galaxy or the Earth’s atmospheric emission. This is an important clue that the observed emission may indeed arise from charge-exchange interactions between the gas surrounding 3I/ATLAS and the solar wind. The X-ray spectrum of 3I/ATLAS shows excesses relative to the background of solar wind ions such as carbon, nitrogen, and oxygen, as indicated by the red arrows. (Credit: JAXA)This pioneering detection of X-ray from an interstellar object will no doubt be followed on by other research teams. It would be particularly interesting to check if there are any other X-ray features different from the expected signatures of charge-exchange reactions with the solar wind. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

An image from a fake AI-generated video on YouTube. (Image credit: Futurism, as reported here)Our perception of reality should be based on verified facts and not AI-generated scripts. In the same way that junk food is bad for the physical health of our body, junk intellectual food is bad for the mental health of our brain. In an interview today on the Will Cain Country podcast (accessible here), I explained that the belief regarding us living in a simulation — akin to a computer game, makes the believers irresponsible. It is a luxury that can be afforded by wealthy individuals; however, those of us who struggle with balancing our bank accounts cannot afford to ignore reality or assume that our actions do not affect other humans as if they were fictitious characters in a simulated game. As a farm boy born with my feet on the ground, I see science as the privilege of figuring out the facts that should guide us. In case we have cosmic neighbors, we better know it irrespective of whether this notion is popular on social media or in computer games. This was the sentiment I conveyed in a new episode of the Danny Jones podcast, accessible here and recorded on the morning after my recent accidental injury. Artificial Intelligence (AI) can easily manufacture fake content, as most recently exemplified by the fictitious YouTube channel which took advantage of my popularity to spread misinformation among the 10 million followers of my essays or video interviews last month. Today, YouTube took down this fake misinformation channel of videos about the interstellar object 3I/ATLAS, which was named after me. This action followed an email exchange with YouTube representatives, during which I sent the following message: “From: Avi Loeb Date: Mon, Dec 8, 2025 at 8:56 AM Subject: Re: YouTube Legal Support To: YouTube Support Team Over the past two weeks, I received hundreds of emails from fans who noticed a YouTube channel named after me with fake videos about the interstellar object 3I/ATLAS, created by artificial intelligence (AI). The channel spreads false content that contradicts my written essays on https://avi-loeb.medium.com/ For the record, I had more than 5 million readers of my essays on this website over the month of November 2025. It was obvious to my fans that the videos were fake because the clock in the background was frozen on a specific time and because two weeks ago — I injured my face on a trip to a Danny Jones podcast interview in Florida — whereas the fake videos did not show any sign of the injury. Nevertheless, a news outlet included one of these videos in a report about my research on 3I/ATLAS, blending reality with fake content when reporting about science. In using AI to generate fake videos impersonating me, this YouTube channel violates several aspects of YouTube’s community guidelines and Terms of Service which should be the basis for YouTube to remove the channel. I hold the entity that created the fake videos legally liable to defamation and false content. By now, my fans and I filed dozens of reports to YouTube but the company did not take responsibility to fix this matter. The reluctance of YouTube to act was already featured in the following News report at the link accessible here. Tonight, I am invited to appear on NBC News to discuss the fake AI content about me on YouTube. I am also in consultation with legal advisors at Harvard University whether to file a lawsuit against YouTube regarding this channel. The story will only get bigger if you do not remove the fake content on this YouTube channel. Thank you for your attention to my privacy complaint. I very much hope that you will remove this channel. Avi Loeb Frank B. Baird Jr. Professor of Science Director, Institute for Theory & Computation Harvard University” Gladly, the legal team of YouTube removed the fake channel shortly after receiving my message. Following the removal of the fake YouTube channel, a representative from NBC News asked me if I kept a clip of the fake videos which are not accessible anymore because they wish to feature an example during tonight’s interview. Gladly, such a video clip was featured in a news report a week ago, where the reporter assumed that it was real. Thank God for bad reporting! ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

A post-perihelion image of the interstellar object 3I/ATLAS taken by the Wide Field Camera 3 onboard the Hubble Space Telescope on November 30, 2025. At that time, 3I/ATLAS was 286 million kilometers from Earth. Background stars appear as streaks of light. The glowing halo (coma) has a teardrop shape with an anti-tail elongated towards the Sun. The sunward direction is pointing towards the lower left, as marked by the yellow arrow. (Image credit: NASA, ESA, STScI, D. Jewitt (UCLA), M.-T. Hui (Shanghai Astronomical Observatory). Image Processing: J. DePasquale (STScI).The interstellar visitor 3I/ATLAS was reobserved by the Hubble Space Telescope from a distance of 286 million kilometers on November 30, 2025, a month after its closest approach to the Sun (perihelion). The image shows a teardrop-shaped glowing halo that extends towards the Sun. This sunward anti-tail extension was also apparent in the pre-perihelion Hubble image of 3I/ATLAS, taken on July 21, 2025, as 3I/ATLAS was approaching the Sun from a distance that is 56% larger from Earth. The new radius of the glow is about 40,000 kilometers and its anti-tail extension goes out to about 60,000 kilometers. In a recent paper, accessible here, I suggested that the teardrop of the coma in post-perihelion images of 3I/ATLAS is associated with a large number of macroscopic non-volatile objects that separated from it as a result of its measured non-gravitational acceleration away from the Sun. My paper predicted that by November 30th, the swarm of objects would be closer to the Sun than 3I/ATLAS by about 60,000 kilometers if the objects overlapped with 3I/ATLAS at perihelion. This separation is in perfect agreement with the anti-tail extension of the teardrop shape in the new Hubble image. A pre-perihelion image of 3I/ATLAS by the Hubble Space Telescope on July 21, 2025. The brightness contours feature an elongation of scattered sunlight towards the Sun and not away from it, as commonly observed for solar system comets. The yellow and green arrows mark, respectively, the projected negative heliocentric velocity vector and the projected anti-solar direction. The angular scale bar of 4” corresponds to 8,650 kilometers at 3I/ATLAS’ distance of 2.98 times the Earth-Sun separation. (Credit: Jewitt et al. 2025)We are awaiting the release of the full Hubble data set which includes ultraviolet spectroscopy to determine the composition of the gas plume around 3I/ATLAS. In the meantime, amateur astronomers continue to provide magnificent large-scale images that extend out to millions of kilometers around 3I/ATLAS. An image of the interstellar object 3I/ATLAS, taken at 1:39 on December 2, 2025 by a 12-inch telescope in Farm Tivoli, Namibia with exposures lasting 20,6,6 and 6 minutes. North is up. The sunward direction is pointing to the lower left. The field of view is 75 by 110 arcminutes corresponding to 6.1 by 9 million kilometers at the distance of 280 million kilometers between 3I/ATLAS and Earth on that date. (Image credit: Gerald Rhemann and Michael Jäger, posted here)*** Addendum: The AI Nemesis of Scientific InformationImagine creating videos that feature avatars of scientists that look like them and speak in their voice, but spread counterfactual information about 3I/ATLAS. How would the public know who to believe? This is not a plot from a science fiction novel but the reality we face today. Over the past two weeks, I received hundreds of emails from fans who noticed a YouTube channel named after me, accessible here, with fake videos about the interstellar object 3I/ATLAS, created by artificial intelligence (AI), that spread false content that contradicts my written essays on https://avi-loeb.medium.com/ It was obvious to my fans that the videos were fake because the clock in the background was frozen on a specific time and because two weeks ago — I injured my face on a trip to a podcast interview in Florida — whereas the fake videos did not show any sign of the injury. Nevertheless, a news outlet included one of these videos in a report about my research on 3I/ATLAS, blending reality with fake content when reporting about science. In using AI to generate fake videos impersonating me, this YouTube channel violates several aspects of YouTube’s community guidelines and Terms of Service which should be the basis for YouTube to remove the channel. I hold the entity that created the fake videos legally liable to defamation and false content. By now, my fans and I filed dozens of reports to YouTube but the company did not take responsibility to fix this matter. We are living in a new reality where fake content can be easily generated by AI. This raises a serious problem of how to authenticate the validity of information on the internet. Science focuses on figuring out the physical reality based on facts. The nemesis of science is fake content created by AI. For our civilization to prosper and advance scientifically, we must develop tools that distinguish fact-based scientific content from hallucinated content spread by AI avatars. *** ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

The annotated and raw version of the preliminary image of the interstellar object 3I/ATLAS, taken on November 2, 2025 by the navigation camera onboard the Juice spacecraft. (Image credit: ESA)As it arrived to perihelion at a distance of 202.9 million kilometers from the Sun on October 29, 2025, the interstellar visitor 3I/ATLAS was hidden behind the Sun from observatories located on Earth. Nevertheless, a week later 3I/ATLAS came close to ESA’s Jupiter Icy Moons Explorer (Juice) which used five of its science instruments to observe our interstellar visitor. The instruments collected data on the composition and shape of the plume of gas and dust around 3I/ATLAS. The data will be transmitted to Earth in February, because Juice is currently using its main high-gain antenna as a heat shield to protect itself from the Sun, leaving its smaller medium-gain antenna to send data at a much lower rate. In addition to using these instruments, Juice imaged 3I/ATLAS with its onboard Navigation Camera (NavCam), designed to help Juice navigate through the icy moons of Jupiter after its arrival to their vicinity in July 2031. Today, ESA released here a preliminary image after downloading a quarter of a single NavCam image. The image displays a glowing halo of gas and dust (coma) surrounding 3I/ATLAS with a hint of two tails. The image was taken on November 2, 2025, during Juice’s first observing run of 3I/ATLAS. It was two days before Juice’s closest approach to 3I/ATLAS, which took place on November 4, 2025 at a distance of about 66 million km. The data from Juice’s five scientific instruments will be released on February 18 and 20, 2026. It will include images from JANUS — Juice’s high-resolution optical camera — as well as spectrometry data from MAJIS and UVS, composition data from SWI, and particle data from PEP. We all wait eagerly for the expected arrival of this data, a month before the closest approach of 3I/ATLAS to Jupiter on March 16, 2025. The fact that 3I/ATLAS will arrive at Jupiter in March 2026 whereas Juice will only get there in July 2031 after their rendezvous in November 2025, illustrates how much faster is this interstellar visitor compared to a human-made spacecraft. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

Image of 3I/ATLAS on November 22, 2025 at 3:00–5:00 UTC based on stacking of 106 images of 60-second exposures, taken with a 0.30-meter telescope at Sternwarte Feuerstein (http://sfeu.de) in Germany. The image shows a teardrop shape of a coma with an anti-tail in the sunward direction, pointing towards the lower left corner. (Image credit: Prof. Dr. Christina Birkenhake).Over the month of November 2025, post-perihelion images of the interstellar object 3I/ATLAS showed a tear-drop shape of its coma with an extension by about an arcminute towards the Sun. During the same period, the JPL Horizons tracking of 3I/ATLAS reported here a non-gravitational acceleration. Its magnitude is a small fraction, of order Δ=0.0002 of the gravitational acceleration from the Sun. In the latest version of JPL Horizons, the non-gravitational acceleration scales inversely with the square of the heliocentric distance (object-Sun separation), exactly as the Sun’s gravitational acceleration. This means that the ratio between the two accelerations remains constant along the orbit of 3I/ATLAS. The dominant component of the non-gravitational acceleration is in the radial direction away from the Sun. A simple way to incorporate it is to consider 3I/ATLAS as accelerating in response to a slightly reduced mass of the Sun, by a fraction of Δ. If 3I/ATLAS is surrounded by a swarm of objects that do not share its non-gravitational acceleration, then these objects will tend to be closer to the Sun relative to 3I/ATLAS, because 3I/ATLAS is pushed away from the Sun relative to the objects through its non-gravitational acceleration. Energy per unit mass is a conserved constant in trajectories shaped by the Sun’s gravity. However, the trajectory of 3I/ATLAS has a slightly smaller gravitational binding energy because of its reduced effective mass of the Sun. If the objects started at the same velocity and position as 3I/ATLAS, then they would have a surplus in gravitational binding energy by a fraction of Δ relative to 3I/ATLAS. However, they would have the same binding energy and track 3I/ATLAS if they have the same velocity and are displaced from its heliocentric distance by a fraction of Δ. At the current separation of 3I/ATLAS from the Sun of 270 million kilometers, the displacement would imply that the objects are closer to the Sun than 3I/ATLAS by about 54,000 kilometers, corresponding to an angular separation of 0.7 arcminutes in the sky. This separation is comparable to the sunward elongation of the teardrop glow around 3I/ATLAS. As long as the objects do not experience non-gravitational acceleration from mass loss as a result of the solar illumination, they should maintain an anti-tail geometry — pointing always towards the Sun relative to 3I/ATLAS and converging to its location at perihelion. A large swarm of objects would have a much larger surface area than that of 3I/ATLAS, even if the total mass in them is a small fraction of the mass of 3I/ATLAS. For example, a trillion (=10^{12}) objects carrying a total fraction of merely 0.001 of the mass of 3I/ATLAS would amount to a total surface area that is 100 times larger than that of 3I/ATLAS. This swarm would create the appearance of a coma that reflects 99% of the sunlight in the glow around 3I/ATLAS. This is consistent with the fraction of light in the coma within the image of 3I/ATLAS taken by the Hubble Space Telescope on July 21, 2025 (as analyzed here). As long as the non-gravitational acceleration of 3I/ATLAS scales inversely with the square of heliocentric distance, the spatial extent of the objects would be of order Δ times the heliocentric distance of 3I/ATLAS, always pointing towards the Sun. This configuration would explain why the teardrop shape towards the Sun existed with a similar angular extent in the glow around 3I/ATLAS as it was approaching the Sun as well as it is now when 3I/ATLAS is moving away from the Sun. If the anti-tail is indeed associated with a swarm of non-evaporating objects around 3I/ATLAS, the interesting question is what is the nature of these objects? Are they rocky fragments or something else? *** Today, I received an uplifting message from a science teach which read as follows: “Dear Professor Loeb, I hope this message finds you well. My name is Joey Rotella, and I teach science at Eastdale Secondary School in Welland, Ontario, Canada. I wanted to reach out to express my appreciation for your work in the study of UAPs and related anomalous phenomena. Your research has been the catalyst for some of the most meaningful discussions I’ve had with my students this semester. We’ve talked not only about the scientific questions themselves, but also about the broader idea that curiosity should not be restricted to topics that are already well-funded or socially comfortable. I’ve shared with them the reality that scientists on the frontier of discovery often face cultural resistance, skepticism, and sometimes real professional risk. You’ve been an example I point to when we discuss the courage it can take to pursue truth rather than convenience. Many of my students had never considered that scientific progress sometimes begins with someone willing to ask an uncomfortable question. I want to thank you personally for that. Your work has inspired me, and if I can pass even a fraction of that inspiration on to my students…if I can help even one young mind feel that curiosity is worth protecting…then it is absolutely worth the effort. Please know that what you are doing is not only advancing a field, but also influencing classrooms like mine. You are, in the fullest sense, a role model for the next generation of scientists. With respect and gratitude, Joey Rotella” *** Here’s hoping that Joey’s students will become scientists and solve some of the mysteries that my generation failed to understand. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

Image of 3I/ATLAS on November 29, 2025 at 21:53 UTC, taken with a 0.26-meter telescope in Rayong, Thailand. Two prominent jets are observed, including an anti-tail in the sunward direction, towards the lower left. (Image credit: Teerasak Thaluang).Following its detection on July 1, 2025, the light from the interstellar object 3I/ATLAS showed pulsating variability with a period of 16.16 hours. The periodic variability, reported here, was measured to have an amplitude of tens of percent. The observers related this variability to a nucleus with an axis ratio of about 0.8. However, the association of this variability with the ellipsoidal shape of the nucleus is not warranted. Based on the Hubble Space Telescope image taken on July 21, 2025 (and reported here), most of the light observed from 3I/ATLAS originates from a glowing halo around it, a coma. This coma is transparent so that the nucleus can be seen through it. The fraction of the total light originating from the reflection of sunlight by the nucleus is unknown, because the nucleus size is not resolved in the Hubble image. However, the brightest pixel in the image presumably overlaps with the nucleus and contains a small fraction of the total light. If all the light were to originate from the solid surface of the nucleus, then the effective radius of the nucleus had to be R_eff=10 kilometers in visible light (as reported here) or R_eff=23 kilometers at a wavelength of 1-micrometer (as reported here) for a typical albedo of 4–5%. However, the actual radius of the nucleus must be much smaller since most of the light is coming from the coma. If the actual radius of the nucleus is R, then the fraction of light that it reflects relative to the total (coma+nucleus) scales as the surface area, (R/R_eff)². For example, the upper limit of R~2.8 kilometers inferred here from the Hubble image, implies that the nucleus reflects less than a percent of the total light at a wavelength of 1-micrometer. If the nucleus is spinning over 16.16 hours, why was the periodic variability at a level of tens of percent in total light? Over the past month, images of 3I/ATLAS showed multiple jets. If the mass loss in the jets is pulsed periodically, the resulting coma would display periodic variability in its scattering of sunlight. In the context of a natural comet, this can arise from a sunward jet (anti-tail) that is initiated only when a large pocket of ice on one side of the nucleus is facing the Sun. As a result, the coma will get pumped up every time the ice pocket is facing the Sun. This resembles a heartbeat with gas and dust serving the role of “blood” in feeding the coma periodically over the rotation period of 16.16 hours. Assuming an outflow velocity of 440 meters per second as suggested in the Webb telescope report here , the distance that sublimated volatiles can reach during 16.16 hours is 25,600 kilometers. This heartbeat pattern should have been apparent in a series of well-calibrated snapshots of the coma over several days but none was systematically studied in the published literature. For a technological object, the direction of the pulsing jet could be arbitrary and not necessarily pointing towards the Sun. A movie showing the periodic brightening of the jets around 3I/ATLAS over several days can reveal whether the jets are natural or technological based on the orientation of the heartbeat pattern relative to the Sun. At any event, it is clear that the reported periodicity over 16.16 hours is not directly associated with the shape of the nucleus but rather with the collimated jets coming from it out to much larger distances. *** And speaking about heartbeat, my heart in recent months is with kids who tell me that they aspire to become scientists after hearing me speak about 3I/ATLAS. Here is the most recent example of a message that I had received before my morning jog at sunrise: “Dear Professor Loeb, My name is Brian. I am 19 years old and I live in Uruguay. I am writing to you because your ideas about the universe, life, and the possibility of other civilizations have deeply inspired me. I come from a humble background and I’m still finding my path, but astronomy has awakened something very strong in me — a desire to understand the world, the universe, and humanity’s place in it. Your work has given me hope that curiosity can lead anyone, no matter where they come from, toward something meaningful. I know you are a very busy person and that you receive many messages, but if you had even a few words of guidance — a direction to follow, something to study, or simply advice for someone beginning this journey — it would mean a lot to me. Thank you for your time, your work, and the inspiration you give to young people like me. Sincerely, Brian Fernández” *** Here’s hoping that many from Brian’s generation will choose to become scientists and solve some of the mysteries that my generation failed to solve. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

Surveys on the Existence of Extraterrestrial Intelligent Life and Effects of Revealing Expert Consensus(Image credit: Omer Eldadi)by Omer Eldadi (1), Gershon Tenenbaum (1) and Avi Loeb (2)Department of Psychology, Reichman University, Herzliya, IsraelDepartment of Astronomy, Harvard University, Cambridge, MA, USA(Submitted for publication in a peer-reviewed journal) Abstract Vickers et al. (2025) established that 58.20% of astrobiology experts believe intelligent extraterrestrial life likely exists, providing the first empirical baseline for public comparison. We surveyed 6,114 highly educated and scientifically engaged individuals (77.60% bachelor’s degree+; 67.99% high-to-very-high scientific engagement) to assess their beliefs about extraterrestrial intelligent life existence: (1) personal beliefs, (2) perceived social circle beliefs, (3) perceived expert beliefs, and (4) responses to expert consensus revelation. Results showed 95.01% believed extraterrestrial intelligent life exists, with 62.59% holding definitive rather than probable convictions. Participants exhibited massive pluralistic ignorance, a ‘cosmic closet’, underestimating social circle beliefs by 46.07 percentage points despite near-universal personal conviction. Participants also exhibited a novel ‘conviction intensity gap’: while overestimating expert belief prevalence (67.63% vs. 58.20% actual), they underestimated expert conviction strength, perceiving only 21.10% as holding definitive beliefs. Experimental revelation of actual consensus (N = 5,106; 83.51% passed manipulation check) produced negligible personal belief change (d = -0.11) and small social belief change (d = 0.14). These findings demonstrate that consensus misperception operates along two dimensions, prevalence and intensity, and that even scientifically engaged audiences resist belief revision via expert consensus information. The scientific community’s beliefs regarding extraterrestrial intelligent life remained largely undocumented through systematic empirical research until Vickers et al.’s survey1. The survey measured astrobiology experts’ (N = 521) agreement with three distinct propositions: (1) the existence of basic extraterrestrial life, (2) extraterrestrial complex life, and (3) extraterrestrial intelligent life. Results revealed a graduated consensus pattern: 86.60% of astrobiologists agreed basic extraterrestrial life likely exists, 67.40% agreed regarding complex life, and 58.20% agreed that intelligent life likely exists somewhere in the Universe. These findings carry theoretical and practical significance. First, they establish that a clear majority of relevant scientific experts support the plausibility of intelligent extraterrestrial life existence. Second, the confidence drop from complex to intelligent life (9.2 percentage points) is less pronounced than the drop from basic to complex life (19.2 percentage points). This suggests that once complex life achieves scientific plausibility, the emergence of intelligence represents a comparatively smaller conceptual leap. Most critically for our purposes, this documented expert consensus provides the essential empirical baseline against which different audiences’ perceptions can now be systematically compared. Public Beliefs About Extraterrestrial Intelligence Existence Research on public attitudes reveals substantial belief in extraterrestrial intelligent life across diverse populations and contexts. The Glocalities study2 surveying 26,492 respondents across 24 countries, found that 47% believe “the existence of intelligent alien civilizations in the universe”. Cross-national variation was substantial, with belief rates ranging from 45% in the United States to 68% in Russia. The Pew Research Center3 revealed that 65% of Americans “say their best guess is that intelligent life exists on other planets”. These findings reveal substantial cross-national variation, with belief rates in individual countries ranging from 45% to 68%, spanning both below and above the documented expert consensus of 58.20%. General population surveys provide limited insight into how different audiences perceive expert opinion. Studies targeting undergraduate student populations, which represent more scientifically engaged audiences, reveal dramatically higher belief rates. Persson et al.4 surveyed 492 Swedish high school and undergraduate university students, reported that 90% believed extraterrestrial life existence. Importantly, the survey did not provide detailed definitions of what constituted “extraterrestrial life”, meaning students may have been thinking about basic life, complex life, intelligent life, or some combination thereof when responding. Most students regarded the search as quite important or very important yet paradoxically did not see themselves as well informed. Critically, students who judged themselves as better informed showed higher belief rates, suggesting that engagement with scientific content may correlate with increased conviction about extraterrestrial life existence, even when that conviction exceeds expert consensus. Extending these findings across cultural contexts, Chon-Torres et al. surveyed 1,237 students from Peruvian public and private universities5, explicitly modeling their research on the Swedish study. Their results revealed that 92% of students “believe in the existence of life outside our planet”. As with the Swedish study, the questionnaire did not specify what type of extraterrestrial life, and researchers acknowledged “it is quite likely that the student respondents were thinking about different forms of life (e.g., microbial, intelligent, etc.)” (p.362) when answering. Like the Swedish findings, Peruvian students considered themselves poorly informed (only 5% described themselves as “very well informed”), yet those rating themselves as better informed showed higher belief rates. The documented spectrum of public beliefs (47%-92%) and expert consensus (58.20%) regarding the existence of extraterrestrial intelligent life raises fundamental questions about how individuals perceive close social circle beliefs, and expert consensus. The phenomenon of pluralistic ignorance6, describes situations where individuals systematically misperceive peer beliefs, believing their private beliefs differ from those of their peers. This mechanism has been demonstrated across diverse domains. College students overestimate peer comfort with heavy drinking while privately feeling uncomfortable, perpetuating drinking cultures through collective misperception7. Applying pluralistic ignorance frameworks to scientific beliefs represents unexplored theoretical territory. Unlike social behavioral norms, which concern conventions and choices, scientific beliefs address factual propositions about the external world. The critical research gap extends beyond merely documenting perception accuracy. Even if misperceptions exist, does revealing documented expert consensus influence personal beliefs, or does it merely correct factual knowledge about expert opinion while leaving personal convictions unchanged? If personal beliefs remain anchored despite learning about expert consensus, it suggests that convictions about extraterrestrial intelligence operate through deeper psychological mechanisms resistant to simple information provision. The Present Research This study addresses these theoretical and empirical gaps by examining two interrelated questions. First, do publics accurately perceive expert consensus on extraterrestrial intelligence? Given that undergraduate student populations hold beliefs exceeding expert consensus by 30–35 percentage points, do they recognize this discrepancy, or do they project their own elevated beliefs onto expert communities? Moreover, do misperceptions operate along multiple dimensions, not just the proportion of experts who believe (prevalence), but also how strongly those experts hold their beliefs (conviction intensity)? Second, does revealing actual expert consensus influence personal beliefs or perceptions of close social circle beliefs? Do individuals adjust their positions toward expert consensus, or do beliefs remain stable despite new information? In addition, we asked participants to evaluate several psychological components which we believe are related to extraterrestrial beliefs. These were anthropocentrism, curiosity, comfortable with ambiguity, skepticism, existential anxiety, institutional trust, science-fiction consumption, UFO/UAP (Unidentified Flying Objects or Unidentified Anomalous Phenomena) content exposure, and social media use. Results Participants Participants’ (N = 6,114) average age was 49.22 years (SD = 13.96), comprised 4,768 males (77.98%), 1,308 females (21.40%), 35 non-binary/third-gender individuals (0.57%) and three ‘prefer not to say’ participants (0.05%). Geographic distribution spanned 112 countries, with largest contingents from United States (38.47%), United Kingdom (6.97%), Spain (6.54%), and Canada (4.45%). The sample exhibited exceptionally high educational attainment: 40.80% with graduate or professional degrees (e.g., MA, MS, MBA, PhD, JD, MD), 36.80% with bachelor’s degrees, 18.70% with secondary education or lower and 3.70% “prefer not to say”. The participants’ scientific engagement score on a 5-likert scale resulted in 23.26% (N = 1,422) rate ‘Very high’, 44.73% (N = 2,735) ‘High’, 27.78% ‘Moderate’ (N = 1,699), 3.58% ‘Low’ (N = 219) and 0.64% ‘Not at all’ (N = 39). This exceptionally educated and scientifically engaged sample (77.60% bachelor’s degree+; 67.99% high/very high scientific engagement) represents an ideal audience for examining consensus perception and responses to expert opinion. Extraterrestrial Intelligent Life Existence by Scientific Engagement Level One-way ANOVA examining personal belief in extraterrestrial intelligent life existence (1 — Definitely does not exist to 5 — Definitely exists) by scientific engagement level (k = 5) revealed a significant main effect, F(4, 6109) = 14.81, p < .001 (see Figure 1). Scheffé post-hoc comparisons (p < .05) indicated a consistent positive association between scientific engagement and belief strength: Level 5 (highest engagement) scored significantly higher than Levels 2 (p < .001), 3 (p < .001), and 4 (p = .012); Level 4 scored significantly higher than Levels 2 (p = .021) and 3 (p = .004). No significant differences emerged between the lowest engagement levels (1–3). Post-hoc comparisons involving Level 1 did not reach significance despite larger mean differences, reflecting insufficient statistical power due to the small cell size (N = 39) rather than absence of true effects. Figure 1 Participant Self-Belief by Scientific Engagement Note. Extremely engaged: M = 4.65, SD = 0.59, N = 1,422; Very engaged: M = 4.57, SD = 0.61, N = 2,735; Moderately engaged: M = 4.50, SD = 0.66, N = 1,699; Slightly engaged: M = 4.42, SD = 0.71, N = 219; Not engaged at all: M = 4.38, SD = 1.07, N = 39. Extraterrestrial Intelligence Existence Beliefs Self-Belief: Personal belief in extraterrestrial intelligence existence showed extreme positive skew (see Table 1). Among the participants (N = 6,114), 95.01% endorsed belief (ratings 4–5), comprising 62.59% ‘Definitely exists’ and 32.42% ‘Probably exists’. Only 1.02% expressed skepticism (ratings 1–2) and 3.97% uncertainty (rating 3). Perceived Close Social Circle Beliefs: Despite near-universal personal belief (95.01%), participants dramatically underestimated agreement within their close social circles, perceiving only 48.94% as believers, a 46.07 percentage point discrepancy (see Table 1). Perceived Experts Beliefs: Participants perceived experts as convinced, estimating 67.63% endorsement, a 9.43 percentage point overestimation compared to actual consensus. However, while overestimating prevalence, participants underestimated conviction intensity. Only 21.10% attributed ‘Definitely exists’ belief to experts, despite 62.59% holding such conviction themselves (self-belief, see Table 1), revealing a previously undocumented “intensity gap” in consensus perception. Table 1 Extraterrestrial Intelligence Self, Social, and Expert Beliefs Distribution Psychological Predictors of Extraterrestrial Intelligence Self-BeliefStepwise multiple regression was performed to test nine psychological predictors of personal belief in extraterrestrial intelligent life existence (N = 6,114). The final model (see Figure 2A) accounted for 13.6% of variance (R = .37, R² = .136, F(6, 6107) = 160.06, p < .001). UFO/UAP content exposure emerged as the strongest predictor (β = .213, p < .001), followed by anthropocentrism (β = -.162, p < .001), curiosity (β = .109, p < .001), institutional trust (β = -.107, p < .001), skepticism (β = -.089, p < .001), and anxiety (β = .038, p = .001). Psychological Predictors of Extraterrestrial Intelligence Social-Belief Stepwise multiple regression examined nine psychological predictors of perceived social circle beliefs in extraterrestrial intelligent life existence (N = 6,114). The final model (see Figure 2B) accounted for 1.2% of the variance (R = .11, R² = .012, F(5, 6108) = 14.81, p < .001). UAP content exposure emerged as the strongest predictor (β = .059, p < .001), followed by curiosity (β = .057, p < .001), social media consumption (β = .035, p = .008), institutional trust (β = .035, p = .008), and science-fiction content consumption (β = .026, p = .049). Psychological Predictors of Extraterrestrial Intelligence Experts-Belief Stepwise multiple regression was performed to estimate the effect of nine psychological predictors of perceived expert beliefs in extraterrestrial intelligent life existence (N = 6,114). The final model (see Figure 2C) accounted for 1.4% of the variance (R = .12, R² = .014, F(4, 6109) = 21.80, p < .001). Institutional trust emerged as the strongest predictor (β = .093, p < .001), followed by UAP content exposure (β = .056, p < .001), anxiety (β = .049, p < .001), and sci-fi content consumption (β = .033, p = .011). Figure 2 Psychological Predictors of Beliefs About Extraterrestrial Intelligence: Self, Social Circle, and Expert Consensus Perceptions Note. Stepwise multiple regression with forward entry (p < .05 inclusion criterion). N = 6,114 for all models. Only significant predictors retained in final models are shown. Correlations Between Extraterrestrial Intelligence Belief Measures We examined the relationships among three types of beliefs about extraterrestrial intelligence: (1) personal beliefs, (2) perceived social circle beliefs, and (3) perceived expert beliefs. Pearson correlation analyses revealed significant positive relationships among all three variables. Personal beliefs were significantly correlated with both social extraterrestrial intelligence belief (see Figure 3), r(6112) = .22, p < .001, and perceived expert beliefs, r(6112) = .21, p < .001. Perceived social circle beliefs were also significantly correlated with perceived expert beliefs, r(6112) = .24, p < .001. These results indicate weak to moderate positive associations among the three belief types, suggesting that individuals’ personal beliefs about extraterrestrial intelligence are somewhat related to their perceptions of both societal and expert beliefs. Figure 3 Correlation Matrix of Extraterrestrial Intelligence Belief Measures (N = 6,114) Note. Correlations are weak to moderate, indicating that the three belief dimensions capture distinct aspects of consensus perception. *** p < .001. The Conviction Intensity Gap Beyond prevalence misperception, analysis revealed systematic underestimation of expert conviction strength, a previously undocumented dimension of consensus misperception. Among the 58.20% of experts who believe extraterrestrial intelligent life exists, Vickers et al. (2025) show in their Figure 1 that ‘strongly agree’ responses were less than ‘agree’ responses, though they did not report the exact proportions. In this study, among participants who attributed belief to experts (rating 4–5, N = 4,135): N = 1,290 (21.10%) rated ‘Definitely’ (perceived as strong conviction), and N = 2,845 (46.53%) rated ‘Probably’ (perceived as moderate conviction). This reveals an intensity gap: participants projected predominantly moderate conviction onto experts (see Figure 4) while participants themselves held definitive beliefs (62.59% rated ‘Definitely’), yet assumed experts remained tentatively convinced despite similar belief prevalence. Figure 4 Personal Beliefs, Social Perceptions, and Expert Consensus: Actual vs. Perceived Intervention Effect: Revealing Expert ConsensusManipulation Check Of the 6,114 participants, 5,106 (83.51%) correctly identified the 58.20% expert consensus on the manipulation check, forming the intervention analysis sample. Participants who passed showed identical baseline patterns to the full sample, confirming that intervention effects were not driven by inattention or differential attrition. Post-Intervention Changes in Personal Beliefs We examined pre-post results of participants who answered correctly on the manipulation check (N = 5,106). The intervention produced minimal change in personal beliefs. A repeated measures ANOVA revealed a significant main effect on personal beliefs, F(1, 5101) = 27.57, p < .001. Pre-intervention belief (M = 4.53, SD = .63) decreased to post-intervention (M = 4.46, SD = .64), representing a statistically significant but practically negligible change (d = -0.11, see Figure 5). The interaction between pre-post measurements and degree of scientific engagement was not significant, F(4, 5101) = 1.40, p = .23, indicating the lack of intervention effect across engagement levels. While overall belief prevalence barely changed (94.71%), the proportion holding ‘Definite exists’ beliefs decreased from 60.54% to 55.66% (−4.88pp), with corresponding increases in ‘Probably exists’ beliefs from 34.33% to 39.05% (+4.72pp). Post-Intervention Changes in Close Social Circle Beliefs Perceived social circle beliefs showed a significant positive shift. A repeated measures ANOVA revealed a significant main effect of F(1, 5101) = 28.48, p < .001. Presented in Figure 5, pre-intervention perceived social belief (M = 3.37, SD = .81) increased to post-intervention (M = 3.48, SD = .77, d = 0.14). The interaction between pre-post measurements and degree of scientific engagement was not significant, F(4, 5101) = 1.01, p = .403, indicating the intervention effect was consistent across engagement levels. Perceived social circle beliefs increased from 48.22% to 53.29% (+5.07pp), partially correcting pluralistic ignorance but leaving a 41.42 percentage point residual gap post intervention between personal (94.71%) and perceived social beliefs (53.29%). Figure 5 Pre-Post Extraterrestrial Intelligence Personal and Perceived Social Circle Beliefs Discussion Our investigation of 6,114 highly educated and scientifically engaged individuals reveals belief dynamics that fundamentally challenge conventional science communication paradigms. Four principal findings emerge: (1) near-universal belief in extraterrestrial intelligence (95.01%) far exceeding actual expert consensus (58.20%), (2) massive pluralistic ignorance with a 46.07 percentage point gap between personal and perceived close social beliefs, (3) the discovery of a previously undocumented “conviction intensity gap” in expert perception, and (4) revealing actual expert consensus produced negligible effects on personal beliefs (d = −0.11), demonstrating profound resistance to informational interventions even among audiences maximally primed for scientific information processing. The phenomenon we term the “cosmic closet” represents one of the largest documented cases of pluralistic ignorance in science communication literature. While 95.01% of participants privately believe extraterrestrial intelligence exists, they estimate only 48.94% of their social circles share this view. This misperception creates a self-perpetuating cycle: individuals remain silent about their beliefs, interpreting others’ silence as skepticism, which reinforces their own reticence. Beliefs about extraterrestrial intelligence existence remain socially constrained despite near-universal private acceptance. This silence likely stems from multiple psychological and social factors. Concerns about appearing unscientific, particularly among educated populations, may suppress expression8,9,10. The historical association of extraterrestrial intelligence beliefs with fringe communities and conspiracy theories creates reputational risk. Additionally, the absence of established social scripts for discussing cosmic questions leaves individuals uncertain about appropriate discourse norms. Our intervention’s partial success, increasing perceived social beliefs by 5.07 percentage points, suggests consensus information can begin recalibrating social perceptions, though the residual 41.42 percentage point gap indicates single-exposure messaging remains insufficient. Our discovery of the conviction intensity gap reveals that consensus misperception operates along two independent dimensions: prevalence and intensity. While participants overestimated the proportion of believing experts (67.63% vs. 58.20% actual), they simultaneously underestimated conviction strength among those believing experts, with only 21.10% attributing ‘Definitely exists’ beliefs to experts. This asymmetry, where participants attribute definitive beliefs to themselves (62.59%) but only tentative conviction to experts, suggests a fundamental attribution error in consensus perception11. Individuals may view their own beliefs as products of careful reasoning while assuming experts’ beliefs remain probabilistic and evidence-contingent. This finding has profound implications for science communication. Current strategies typically report simple prevalence statistics (“X% of scientists believe…”) 12,13, neglecting the conviction dimension. Our results suggest that communicating both dimensions: how many experts believe and how strongly they believe, may more accurately convey scientific consensus and potentially enhance its influence on public opinion. The psychological predictors revealed distinct patterns across belief dimensions. UFO/UAP content exposure emerged as the strongest predictor of personal beliefs (β = .213), though the cross-sectional design precludes causal inference, whether exposure cultivates belief or believers seek confirming content remains undetermined. Anthropocentrism showed a strong negative association (β = −.162), consistent with theoretical frameworks linking cosmic perspective to reduced human exceptionalism. Lower institutional trust predicted higher personal belief (β = −.107), suggesting that distrust in official narratives may paradoxically increase openness to extraterrestrial possibilities. Notably, the variance explained in perceived social beliefs (1.2%) and expert beliefs (1.4%) was markedly lower than for personal beliefs (13.6%), indicating that social perceptions operate through different mechanisms, potentially heuristic processes or social projection rather than deliberative assessment of others’ positions. The subtle finding that “definite” beliefs decreased by 4.88 percentage points while “probable” beliefs correspondingly increased suggests the intervention produced epistemic humility rather than belief revision. This modulation of certainty without abandoning core beliefs indicates consensus information may influence metacognitive confidence even when failing to change belief direction. Participants adjusted the strength of their conviction while maintaining their fundamental position, a pattern consistent with motivated reasoning frameworks where individuals assimilate challenging information in ways that preserve core beliefs. Conclusion This study establishes that beliefs about extraterrestrial intelligence among scientifically engaged publics operate through mechanisms distinct from conventional scientific beliefs, carrying three key implications. First, the 36.81 percentage point gap between public belief (95.01%) and expert consensus (58.20%) among highly educated audiences suggests not scientific illiteracy but rather different epistemological frameworks for evaluating cosmic questions. Second, the discovery of massive pluralistic ignorance, the “cosmic closet”, indicates the primary barrier to public discourse is not skepticism but misperceived social norms. With 95.01% privately believing but assuming majority skepticism, individuals self-censor, perpetuating false perceptions of minority status. This finding suggests communication strategies should prioritize revealing existing consensus among peers rather than attempting to change beliefs already near ceiling. Third, the conviction intensity gap represents a novel contribution to understanding consensus perception, demonstrating that people track not just what experts believe but how strongly they believe it. This two-dimensional model of consensus perception: prevalence and intensity, opens new theoretical and practical avenues for science communication research beyond the extraterrestrial domain. Our findings suggest the public, at least among scientifically engaged communities, exhibits greater readiness for potential discovery than experts assume. The challenge lies not in convincing skeptics but in creating social conditions where existing believers feel comfortable expressing their convictions, enabling informed public discourse about humanity’s possible cosmic companions. Method Participants Participants were recruited via social media platforms such as Medium, Twitter, LinkedIn and WhatsApp. Data collection occurred between November 10–16, 2025, through an embedded survey link. To be eligible for the study, participants were at least 18 years old. Sample size was calculated using G*Power 314 for the primary analyses. To ensure the study was sufficiently powered to detect even very small effects, parameters were set at an effect size of f = 0.1 with 80% power at α = .01 for the primary analyses. This calculation yielded a required sample size of approximately N = 1,800, which our achieved sample exceeds. A total of N = 6,114 adults completed the survey. For intervention analyses examining consensus information effects, we additionally required correct responses to a manipulation check verifying participants read and processed the expert consensus information. This criterion (passing manipulation check) identified N = 5,106 participants (83.51% of total sample) for intervention analyses. Measurements (see appendix A for full questionnaire) Demographic Questionnaire (DQ). The DQ includes items on country, age, gender, education level and levels of engagement with science-related topic. Psychological Predictors. Beyond demographic factors, we measured psychological orientations theoretically relevant to beliefs about extraterrestrial intelligence: anthropocentrism (humans’ specialness), curiosity, tolerance for uncertainty, skepticism, existential anxiety, institutional trust, and media exposure: science fiction consumption, UFO/UAP content exposure and social media use. The psychological variables were assessed via single-item self-report measures using 5-point Likert scales: (1 = ‘Not at all’ to 5 = ‘Extremely’). Media consumption was assessed via single items for science fiction exposure (weekly hours), UFO/UAP content frequency (1 = Never to 5 = Very frequently), and social media use (daily hours). Complete items available are presented in appendix A. Baseline Belief Measures. Three parallel items assess beliefs before intervention: · Personal belief: “To what extent do you believe that intelligent extraterrestrial life exists somewhere in the universe beyond Earth?” · Perceived social circle belief: “To what extent do you think most people in your social circle believe that intelligent extraterrestrial life exists somewhere in the universe beyond Earth?” · Perceived expert belief: “To what extent do you think most astrobiology experts believe that intelligent extraterrestrial life exists somewhere in the universe beyond Earth?” All items used identical 5-point Likert-type scales ranging from 1–5 ( 1 — Definitely does not exist, 2 — Probably does not exist, 3 — Uncertain/don’t know, 4 — Probably exists, 5 — Definitely exists. Intervention Participants read: “Recent research by Vickers et al. (2025) surveyed over 500 astrobiology experts about extraterrestrial life. The study found that 58.20% of experts believe intelligent extraterrestrial life likely exists somewhere in the universe. This represents the first systematic documentation of scientific expert opinion on this question”. · Manipulation Check. “According to the research mentioned, what percentage of experts believe intelligent extraterrestrial life likely exists?” Options: 58.20% (correct), other (incorrect). Incorrect responses indicated failure to process consensus information. Procedure After providing informed consent, participants completed demographic questions, psychology factors and baseline belief measures. They then read the intervention text presenting actual expert consensus regarding the likelihood of extraterrestrial intelligent life. The manipulation check followed immediately, where participants were asked to select the correct expert consensus of 58.20% from 5 options. If they chose a wrong option, they were excluded for the pre/post comparison data analysis. Finally, participants re-rated their personal and social circle beliefs. The survey concluded with debriefing information about the study’s purpose. Participants re-rated personal and social circle beliefs using identical scales, allowing within-subject comparison of pre-post changes. Data Analysis All analyses were conducted using SPSS Statistics (Version 29). Statistical significance was set at α = .05 for all tests. Descriptive analyses examined belief distributions using frequency tables and percentages. We calculated endorsement rates by collapsing 5-point scales into “Yes” (ratings 4–5), “Uncertain/don’t know” (rating 3), and “No” (ratings 1–2) categories. Between-group comparisons employed one-way ANOVA examining personal beliefs across five scientific engagement levels, with Scheffé post-hoc tests for pairwise comparisons. Intervention effects were analyzed using repeated measures ANOVA with pre-post as the within-subjects factor and scientific engagement as the between-subjects factor. This design tested both main effects of the intervention and potential moderating effects of scientific engagement on belief change. Separate analyses examined personal beliefs and perceived social circle beliefs as dependent variables. Pluralistic ignorance was assessed by comparing personal beliefs (self-rated) against perceived social circle beliefs at baseline. Effect sizes were calculated as Cohen’s d with benchmarks of d = 0.2 (small), d = 0.5 (medium), and d = 0.8 (large) following Cohen15. Psychological predictors were examined using stepwise multiple regression with forward entry. Nine predictor variables (anthropocentrism, curiosity, tolerance for uncertainty, existential anxiety, institutional trust, science fiction consumption, UFO/UAP content exposure, social media use, and skepticism) were entered, with inclusion criterion of p < .05. Separate regression models predicted (i) personal beliefs, (ii) perceived social circle beliefs, and (iii) perceived expert beliefs. Correlational analyses used Pearson product-moment correlations to examine relationships among the three belief measures (personal, perceived social circle, and perceived expert beliefs). Manipulation check success (correctly identifying 58.20% as the expert consensus figure) served as the inclusion criterion for intervention analyses, reducing the sample from N = 6,114 to N = 5,106. Acknowledgements A.L. was supported in part by Harvard’s Black Hole Initiative and the Galileo Project. Author Contributions All authors conceived the study, designed the survey, collected data, performed analyses, and wrote the manuscript. Competing Interests The authors declare no competing interests. Data Availability Raw data available at: https://docs.google.com/spreadsheets/d/1VNIJCzuAmKjb5LcEtS4iHjJi6OnXyZ7mwGFcTeB8Vck/edit?usp=sharing Ethics Statement This study was approved by Reichman University IRB Ethics Committee. Ethical clearance number: P_2025220 All participants provided informed consent. References [1] Vickers, P, Gardiner, E, Gillen, C, Hyde, B, Jeancolas, C, Finnigan, SM, Nováková, JN, Strandin, H, Tasdan, U, Taylor, H & McMahon, S. (2025), Surveys of the scientific community on the existence of extraterrestrial life, Nature Astronomy,9(1), pp. 16–18. https://doi.org/10.1038/s41550-024-02451-0 [2] Lampert, M., & Papadongonas, P. (2017). Majority of humanity say we are not alone in the universe: Values-based learnings from the Glocalities survey in 24 countries. Glocalities. https://glocalities.com/reports/majority-of-humanity-say-we-are-not-alone-in-the-universe [3] Kennedy, C., & Lau, A. (2021, June 30). Most Americans believe in intelligent life beyond Earth; few see UFOs as a major national security threat. Pew Research Center. https://www.pewresearch.org/short-reads/2021/06/30/most-americans-believe-in-intelligent-life-beyond-earth-few-see-ufos-as-a-major-national-security-threat/ [4] Persson E., Capova K.A., Li Y. (2019). Attitudes towards the scientific search for extraterrestrial life among Swedish high school and university students. International Journal of Astrobiology, 18(3):280–288. doi:10.1017/S1473550417000556 [5] Chon-Torres O.A., Ramos Ramírez J.C., Hoyos Rengifo F., Choy Vessoni R.A., Sergo Laura I., Ríos-Ruiz F.G.A., Murga-Moreno C.A., Alvarado Pino J.P.L., Yance-Morales X. (2020). Attitudes and perceptions towards the scientific search for extraterrestrial life among students of public and private universities in Peru. International Journal of Astrobiology, 19, 360–368. https://doi.org/10.1017/S1473550420000130 [6] Miller, D. T., & McFarland, C. (1987). Pluralistic ignorance: When similarity is interpreted as dissimilarity. Journal of Personality and Social Psychology, 53(2), 298–305. https://doi.org/10.1037/0022-3514.53.2.298 [7] Prentice, D. A., & Miller, D. T. (1993). Pluralistic ignorance and alcohol use on campus. Journal of Personality and Social Psychology, 64(2), 243–256. [8] Goffman, E. (1963). Stigma: Notes on the management of spoiled identity. Simon & Schuster. [9] Major, B., & O’Brien, L. T. (2005). The social psychology of stigma. Annual Review of Psychology, 56, 393–421. https://doi.org/10.1146/annurev.psych.56.091103.070137 [10] Lantian, A., Muller, D., Nurra, C., & Douglas, K. M. (2018). Stigmatized beliefs: Conspiracy theories, anticipated negative evaluation of the self, and fear of social exclusion. European Journal of Social Psychology, 48(7), 939–954. https://doi.org/10.1002/ejsp.2498 [11] Ross, L. (1977). The intuitive psychologist and his shortcomings: Distortions in the attribution process. In L. Berkowitz (Ed.), Advances in experimental social psychology (Vol. 10, pp. 173–220). Academic Press. https://doi.org/10.1016/S0065-2601(08)60357-3 [12] van der Linden, S. (2021). The Gateway Belief Model (GBM): A review and research agenda for communicating the scientific consensus on climate change. Current Opinion in Psychology, 42, 7–12. https://doi.org/10.1016/j.copsyc.2021.01.005 [13] van Stekelenburg, A., Schaap, G., Veling, H., van ’t Riet, J., & Buijzen, M. (2022). Scientific-consensus communication about contested science: A preregistered meta-analysis. Psychological Science, 33(12), 1989–2008. https://doi.org/10.1177/09567976221083219 [14] Faul, F., Erdfelder, E., Lang, A. G., & Buchner, A. (2007). G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behavior Research Methods, 39(2), 175–191. https://doi.org/10.3758/BF03193146 [15] Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Routledge. https://doi.org/10.4324/9780203771587 Appendix A — Survey ABOUT THE POSTING CO-AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

Image of 3I/ATLAS, taken on November 26, 2026. (Credit: Julien de Winter)The non-gravitational acceleration of the interstellar object 3I/ATLAS is routinely updated by Davide Farnoccia on NASA’s JPL Horizons website here. On October 30, 2025, the value of the radial acceleration component A1 — normalized at a heliocentric distance of the Earth-Sun separation (=1 au), was listed as 1.6x10^{-6} au per day squared. By November 24, the coefficient A1 was reduced by a factor of 4 to a value of 4x10^{-7} au per day squared. At that time, I pointed out here that the minimum perijove distance of 3I/ATLAS during its encounter with Jupiter on March 16, 2026 is forecasted to be 53.445 (+/- 0.06) million kilometers, identical within one standard deviation to Jupiter’s Hill radius at the perijopve time, 53.502 million kilometers. Interior to that radius, Jupiter’s gravity dominates of the Sun’s tide. Any small satellite deposited outside this radius will be removed from Jupiter by the Sun’s gravity. Surprised by the unexpected match between the perijove distance of 3I/ATLAS and the Hill radius of Jupiter on March 16, 2026, I emailed Davide my report here about this unlikely coincidence. There was no response to my email. However, within a couple of days the listed A1 on NASA’s JPL Horizons website here was revised downward by a factor of 6 to a value of 6.8x10^{-8} au per day squared, with a new model for the radial dependence of the non-gravitational acceleration. The new model uses an inverse square dependence on distance from the Sun: 1/r², as appropriate for the sublimation of carbon dioxide (CO2) ice interior to a heliocentric distance of 5 au. This new model replaces the steeper radial dependence associated with the previous model used by NASA’s JPL Horizons — suitable for the sublimation of water (H20) ice based on work by Brian Marsden and collaborators, as described here and here. Given these revisions, the new JPL Horizons forecast for the perijove distance of 3I/ATLAS is now 53.587 (+/- 0.045) million kilometers, slightly outside the Hill radius on March 16, 2026. However, this forecast relies on a 1/r² model which uses past contributions from larger heliocentric distances to explain the measured deviation of 3I/ATLAS from its original gravitational path. The new model of JPL Horizons is likely inadequate. There is strong evidence that 3I/ATLAS became brighter near perihelion than the smooth 1/r² model would predict. Correcting the radial dependence of the non-gravitational acceleration of 3I/ATLAS to accommodate this evidence is likely to bring the perijove distance back to agreement with the Hill radius value. A steeper radial profile of the non-gravitational acceleration of 3I/ATLAS near perihelion than the 1/r² model is suggested by the evolution of the luminosity of 3I/ATLAS. Based on the image obtained by the Hubble Space Telescope on July 21, 2025 (and reported here), the luminosity is dominated by the coma and reflects the mass loss if the total amount of scattered sunlight is proportional to the coma mass. The luminosity evolution was reported in a new preprint here by Marshall Eubanks and collaborators. An earlier report by Qicheng Zhang and Karl Battams here suggested a steep luminosity profile of 1/r^{7.5} inside 2 au as 3I/ATLAS was making its way to the perihelion distance at 1.36 au on October 29, 2025. Adopting this steep radial dependence would change the expected perijove distance towards a closer agreement with Jupiter’s Hill radius. The insistence of the Vatican on the Earth being at the center of the solar system did not change the orbit of the Earth around the Sun. For the same reason, the new model of JPL Horizons will not change the actual trajectory of 3I/ATLAS. We will know whether the perijove distance agrees with the Hill radius in the coming months thanks to data collected as 3I/ATLAS approaches its perijove on March 16, 2026. In particular, astrometric data from the spacecraft Juno, Juice or Psyche will be very useful for settling the issue. Since 3I/ATLAS was hidden by the Sun from terrestrial telescopes during its perihelion passage — when it gained most of its non-gravitational acceleration, we might only have a tight constraint on the integrated drift of 3I/ATLAS from its gravitational path but not on its radial dependence close to perihelion. If the rare coincidence between the perijove distance of 3I/ATLAS and the Hill radius will materialize, it might flag a technological signature. In that case, 3I/ATLAS could release technological devices as artificial satellites of Jupiter, potentially at Jupiter’s Lagrange points L1 and L2 on the Hill sphere — where orbital corrections and fuel requirements are minimal. Within the diameter of Jupiter’s orbit around the Sun, the coincidence between the perijove distance and the Hill radius has a statistical likelihood smaller than 0.00004. In case the non-gravitational acceleration was needed to achieve this match, the rare coincidence will constitute the most remarkable anomaly of 3I/ATLAS so far in the list compiled here. The final verdict on this matter will eventually be posted on the JPL Horizons website, underlining the inescapable truth that science is always work in progress, not to be settled by the authority of NASA officials in press conferences. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

(Image credit: Cosmin4000/Getty Images)In the long tradition of scientific wagers, Skeptic magazine publisher and historian of science Dr. Michael Shermer has issued a $1000 bet that… Discovery or disclosure of alien visitation to Earth in the form of UFOs, UAPs, or any other technological artifact or alien biological form, as confirmed by major scientific institutions and government agencies, will not happen by December 31, 02030. Taking him up on that challenge is Harvard astronomer and Director of the Galileo Project Dr. Avi Loeb. The wager is placed through the Long Now Foundation’s Long Bets program (“an arena for competitive, accountable predictions”), which adds a 0 at the front of all dates on a 10,000 year calendar (“to foster better long-term thinking”), in keeping with their Clock of the Long Now, being built in Texas and designed to tick for 10,000 years. Details of the Shermer-Loeb wager may be found here. Whoever wins, the $1000 stakes will be donated to the Galileo Project Foundation. Here are the terms for deciding who wins: By Dec 31st 02030, at least two of these three scientific organizations — NASA, the National Science Foundation, and the American Astronomical Society — will affirm that discovery of extraterrestrial intelligence in the form of UAPs, UFOs, or any other interstellar objects that are determined to be ETI technological in nature, or any alien biological life form found here on Earth, has been made. Here is Dr. Loeb’s argument: The search for technological artifacts has just started in earnest in 2025 with the discovery of the anomalous interstellar object 3I/ATLAS, the launch of the Rubin Observatory and the construction of three Galileo Project Observatories. Given that there are billions of Earth-Sun analogs in the Milky-Way galaxy — most of which are billions of years older than the solar system, and that it will take less than a billion years for our Voyager spacecraft to cross the Milky-Way disk, we must engage in the scientific search for extraterrestrial technological artifacts. It is better to be an optimist because life is sometimes a self-fulfilling prophecy. This is why I am engaged in the search with the hope that we will find a partner on our blind date with interstellar objects. Here is Dr. Shermer’s argument: Since the founding of the Skeptics Society and Skeptic magazine in 1992, I have been documenting predictions by UFOlogists that discovery or disclosure of alien visitation to Earth is coming any day now. Believers appear in the media boldly predicting that by the end of the year we will have proof of alien contact — 33 years later I’m still waiting for said proof. More recently, proponents of UAPs as alien spacecraft have appeared before the U.S. Congress, confidently claiming that they know people who have seen and even touched aliens and/or their spaceships, back-engineered their technologies, and even communicated with the aliens. Yet when pushed for evidence, they always demur, saying that it’s “classified”, “top-secret”, that Men-in-Black threatened them into silence, that their careers and even their lives are at stake if they disclose said evidence, that they could only reveal the evidence in a “SCIF” (Sensitive Compartmented Information Facility) but not in Congress, and that many people in the U.S. government, CIA, FBI, NSA, etc. (never named) have this information and evidence of alien visitation. The purpose of this bet, in keeping with the rules of Long Bets and the philosophy of the Long Now Foundation, is to reveal the actual confidence of UFO/UAP alien believers by getting them to put their money where their beliefs appear to be. You say we will have alien disclosure by the end of the year? O-kay, let’s place a wager on that prediction. I say it won’t happen. The Long Bets program was started in 2003 by Stewart Brand and Kevin Kelly, and is part of a long tradition of scientific wagers dating back at least to 1870 when Alfred Russel Wallace, co-discoverer with Charles Darwin of natural selection, accepted a £500 wager (a workingman’s wages for one year) placed by flat-Earther John Hampden that scientists could not prove that the Earth is round. Wallace proved it by demonstrating same-height poles placed at even intervals along a six-mile stretch of the Old Bedford Canal (north of London) appeared through a telescope lower by the exact “amount calculated from the known dimensions of the earth.” Unfortunately, Wallace had to take Hampden to court to collect his winnings. Thus, it is important that such wagers be professionally adjudicated by neutral referees. Other wagers include: · In 1975, cosmologist Kip Thorne bet cosmologist Stephen Hawking that Cygnus X-1 was a black hole. Thorne won. · In 1980, biologist Paul Ehrlich bet economist Julian Simon that the price of a portfolio of five mineral commodities (copper, chromium, nickel, tin, and tungsten) would rise in price over the next decade. Simon won. · In 1998, neuroscientist Christof Koch bet philosopher David Chalmers that the Hard Problem of Consciousness (a term coined by Chalmers) would be solved in 25 years. Chalmers won. · In 2017, astronomer Martin Rees bet psychologist Steven Pinker that “a bioterror or bioerror will lead to one million casualties in a single event within a six-month period starting no later than December 31, 02020.” Since the lab-leak hypothesis for Covid-19 (bioerror) was never proven, Pinker was declared the winner on the Long Bets platform. If Loeb wins the bet, it will represent what would arguably be the greatest discovery in human history, namely that we are not alone in the universe. If Shermer wins the bet, it does not mean that we are the only intelligence in the cosmos, only that claims of contact are likely greatly exaggerated and that we need to keep searching for the truth about extraterrestrial intelligence. A couple of weeks ago, the accomplished sculptor Greg Wyatt gave Loeb a foundation to create an original bronze sculpture, which Loeb labeled in advance: “The Alien.” Loeb plans to create the image of an extraterrestrial being with a body better than the human body, including additional eyes — enabling vision in all directions, additional legs — enabling better mobility, additional wings and fins — enabling motion in fluids and gases, and most importantly — a larger brain empowered by AI. Time will tell if Loeb’s vision is manifested in the cosmos. ABOUT THE POSTING AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

An image of 3I/ATLAS, taken on November 22, 2025 at 19:25 UTC with a 0.5-meter telescope. At that time, 3I/ATLAS was close in projection to the galaxy NGC4454 in the sky. The sunward direction is towards the lower left corner. (Credit: Mitsunori Tsumura)A number of images of the interstellar object 3I/ATLAS were taken on November 22–24, 2205 by amateur astronomers and astrophotographers. They consistently show a glowing coma with tightly-collimated anti-tail and tail. The best image (available here) was taken by Mitsunori Tsumura on November 22 at 19:25 UTC with a 0.5-meter telescope. Given the current distance of 3I/ATLAS from Earth of 300 million kilometers, its tail appears to extend out to 5 million kilometers whereas the sunward anti-tail extends out to about a million kilometers. It takes a month to cross a million kilometers at a speed of 400 meters per second. The huge extent of the anti-tail towards the Sun implies that it carries a large enough momentum flux to penetrate through the solar wind. The anti-tail’s ram-pressure exceeds that of the solar wind out to that distance. The solar wind is flowing at a speed of about 400 kilometers per second, which is at least a thousand times faster than the thermal speed of outflowing gas from a natural comet at the location of 3I/ATLAS. Since ram-pressure scales as the gas speed squared, this means that the outermost mass density in the anti-tail is a million times bigger than the solar wind density of a few proton masses per cubic centimeters. For a natural comet, the outermost mass density of the anti-tail implies a mass flux of 200 tons per second per square area of size 0.3-million kilometer on a side. Counting also the tail, this yields a total mass loss rate of about a few billion tons over the past two months. For a natural comet, the estimated mass loss over the months of October and November 2025 is about 10% of the minimum mass associated with 3I/ATLAS, 33 billion tons — that I calculated here based on the lack of non-gravitational acceleration during the months of July, August and September 2025. Any such acceleration would stem from the anisotropy in the mass loss rate times the outflow speed, divided by the object mass. Since then, a non-gravitational acceleration was actually measured around perihelion in October 2025. By now its detection, reported here by JPL Horizons, is statistically significant at ten standard deviations. Momentum conservation at the maximum thermal gas speed of 400 meters per second implies that the measured level of non-gravitational acceleration requires more than 10% of the mass of 3I/ATLAS to be lost if it is a natural comet, as I showed here. Jets from technological thrusters could be more effective in accelerating 3I/ATLAS with less mass loss, as they produce higher exhaust speeds. The required mass loss to penetrate through the solar wind is scaled down by the square of the increased outflow speed. This corresponds to 2 or 4 orders of magnitude reduction in mass loss for chemical thrusters or ion thrusters, respectively. Future spectroscopic measurements could assess the speed of the jets and distinguish between the natural sublimation of pockets of ice by sunlight and technological alternatives. An image of 3I/ATLAS, taken on November 21, 2025. (Credit: Paul Craggs)The unusually elongated appearance of 3I/ATLAS, as reported here by Paul Craggs on November 22, 2025, might have resulted from motion smearing of the image. An image of 3I/ATLAS, taken on November 22, 2025 at 5:28 UTC with a 0.315-meter telescope in Spain. (Credit: Peter Carson Leigh)Two other images consistent with the anti-tail/tail morphology were taken by Peter Carson Leigh at 5:28 UTC on November 22, 2025 with a 0.315-meter telescope in Spain and by Elena Walter at 8:05 UTC on November 24, 2025 with a 0.432-meter telescope in Chile. We are all awaiting better images from the largest telescopes on Earth, as well as from the Hubble and Webb Space Telescopes, near 3I/ATLAS’s closest approach to Earth on December 19, 2025 at a minimum distance of 269 million kilometers. The best is yet to come. The data collected in December 2025 will set the verdict on the nature of 3I/ATLAS. In addition, we will be able to assess whether 3I/ATLAS is forecasted to reach the Hill radius of Jupiter on March 16, 2025 — as discussed here, to better than four significant digits. An image of 3I/ATLAS, taken on November 24 at 8:05 UTC with a 0.432-meter telescope in Chile. (Credit: Elena Walter, Liena Dreams)ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

An image of 3I/ATLAS, taken on November 24 at 8:05 UTC with a 0.432-meter telescope in Chile. (Credit: Elena Walter, Liena Dreams)In anticipation of Thanksgiving, I have received over the past day the following letters of gratitude concerning the interstellar object 3I/ATLAS: Letter 1 “Hi Avi! (I use the familiar voice, because I feel like you are humanity’s best friend at this moment — the one unafraid to ask the most important questions to which we do not yet know the answers…and seemingly fearlessly at that!) Since your very earliest writings about 3I/ATLAS, I’ve been looking forward to the emails from my new friend Avi to point out, with all due scientific and professional rigor/skepticism, what questions humanity should be asking of our institutions and about our newest interstellar visitor. You haven’t ever let us down. Even on days without new data to share, I marvel at the work you’ve done to both refine your delivery for accessibility to the non-scientifically minded and to welcome everyone who takes the time to read your work into the collective mystery…all without gatekeeping or condescension. (It’s not every intellectually curious/highly-educated being that can do that!) Thank you for your courage to publicly continue the exploration in the face of all the ridiculous (and rather pathetic, if you ask me) ridicule lobbed at you. I wish I had been a Professor like you at a University. I’d likely have followed my dreams of becoming a Cosmologist if I had! Cosmically Yours, Matthew Riley” Letter 2 “Howdy from Houston, Professor Loeb! I wanted to add to the flood of mail in your inbox just to share my enthusiasm for your work and your ability to communicate the important role of science in general and of astrophysics in particular today. I’ve been following your posts since the announcement of 3I/ATLAS and I’m shocked, but sadly not surprised, at the overwhelmingly anti-scientific stance that so many people seem to take toward the big questions in the cosmos. Surely fear and information hiding cannot get us to a better future. They never have. On that note, I wrote some book recommendations for my LinkedIn followers this morning and included this mention of you: — No current reading list on the sky would be complete without including Avi Loeb, the controversial astrophysics professor from Harvard who is adamant that we should examine all of space scientifically and not with military or political intent. Interstellar is his second popular-level book (I finished his first two weeks ago) and does a wonderful job of breaking down the practical reasons that we must look at space in a new way than we did before. Our modern instruments and scientific knowledge of the formation of the universe simply compel to us look more carefully — in order to find out about our own origins. And this leads to the Big Takeaway I’m finding from all of these modern books, discussions, and documentaries on astrophysics. They all talk about life on other planets! This was not even a topic of space discussion when I was a child. It was a fringe subject for wackos. What’s changed is that now we know that life itself can arise from the quantum conditions of the Big Bang (over a great deal of time, of course) and since that bang spread out everywhere, there are many potential places where life like ours — or unlike ours — can likely be. Them’s the facts, ma’am! These are exciting times on the ultimate frontier, the view from this Spaceship Earth, as Ray Bradbury called it, on which we’re merely passengers. — Thank you for all you’re doing, Professor Loeb, and be well! — David Bethune” Letter 3 “Avi, I don’t think I’ve ever been so impressed with anyone in my lifetime as I am with you. Standing up to, what it seems like everyone!! At times, and you never flinched once, ever… Good on you, I’m 63 retired but the young man who now owns my boat is next generation of my line. I’ll be going up to Massachusetts next June to teach him the trade of harpooning bluefin, you have an open invitation to come with us. A day or two off the backside of the Cape would be good escape and a chance to see something special Proud of you, stay your course…. Corky” Letter 4 “Dear Dr. Loeb, I wanted to take a moment to express my appreciation for your work. Your combination of scientific rigor, intellectual generosity, and genuine humility is rare and deeply inspiring for those of us following your research from the sidelines. My own background is in radiology and clinical nutrition, with a growing focus on physiology, biochemistry, and science communication. I’ve been developing an educational comic series to make complex biological concepts easier for students to understand. It’s a small project compared to the scale of your work, but it reflects how much I value clear, accessible science. If your research ever intersects with areas where imaging, biological interpretation, or health science perspectives could be useful, I would be grateful for any opportunity, even a minor one, to contribute. And if humanity ever finds extraterrestrial visitors with suspicious bone density or questionable micronutrient status, I promise I’ll keep a ready eye on both the skeletons and the vitamins. Thank you for the example you set in how curiosity and humility can coexist at the highest levels of science. It genuinely means a lot. With respect, Azadeh” Letter 5 “Dear Dr. Loeb, I wanted to thank you for the wonder and open-mindedness you bring to the field of astronomy. Your work, particularly your approach to Oumuamua and the Galileo Project, has deeply inspired me. As an artist who often weaves science into my work, I recently released a song titled “3I/ATLAS, The Star Whisperer”, which was directly influenced by your theories about interstellar objects. While the song has some poetic interpretation, it’s ultimately a reflection of curiosity, the spirit of exploration, and how your ideas inspired a reimagining of what’s possible. If you ever have a moment to listen, it would mean the world to me. Here’s the song: Spotify: https://open.spotify.com/track/7xkmReT3ERYZP1ouCipVLe?si=4eiTAepTRJaYYRM7ribUSQ YouTube: https://youtu.be/DFu-1naCMk8?si=b80bjdR0ctsGKHCL Thank you again for helping so many of us keep wonder alive in science. Warmly, Suzee” Letter 6 “Dear Professor Loeb, I hope this email finds you well. I am writing to you from Manila, Philippines. I’ve been following your work regarding ‘Oumuamua, the Galileo Project, and your recent discussions on the Joe Rogan Experience about 3I/Atlas… ESPECIALLY 3I/ATLAS! That thing is CRAZZZY, Sir! hahaha I wanted to reach out and tell you that your persistence has had a profound impact on me personally. In a world that often feels cynical or “closed,” your willingness to look at the anomalies — to chase the “glitches” in the sky — reminds me to keep looking for the magic in my own life. Here in the Philippines, we have a word called “Kilig.” It’s usually used for romantic excitement, but it also describes that sudden, shivering thrill of possibility — the feeling you get when you realize the universe might be bigger and more wonderful than you thought. Your work gives me that “Kilig.” Thank you for being the one to “look out the window” while everyone else argues about the room. You’ve inspired me to keep my eyes open, whether I’m looking at the stars or just driving my old Honda City through the province. Please keep searching. We are watching, and we are rooting for you. With deepest respect and admiration, Guile (A fan from the Philippines)” *** Happy Thanksgiving to all earthlings! Stay curious. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

A false-color image of 3I/ATLAS, taken on November 22, 2025. The sunward direction is towards the lower left. (Credit: Alfons Diepvens, Belgium)The time is ripe to summarize the anomalies of the interstellar object 3I/ATLAS in ascending order of likelihood. Here is the list, split into three categories, along with the probability, P, associated with each item: I. Major anomalies with no simple explanation: 1. P=0.00004: The forecasted perijove distance of 3I/ATLAS during its encounter with Jupiter on March 16, 2026 is 53.445 (+/- 0.06) million kilometers, identical to Jupiter’s Hills radius, 53.502 million kilometers (see here). This match was enabled by the non-gravitational acceleration that 3I/ATLAS displayed near perihelion. The rare coincidence might mean that 3I/ATLAS intends to release technological devices as artificial satellites of Jupiter, potentially at Jupiter’s Lagrange points L1 and L2. 2. P=0.00005: The arrival time of 3I/ATLAS was fine-tuned to bring it within tens of millions of kilometers from Mars, Venus and Jupiter and be unobservable from Earth at perihelion (see here). 3. P<0.001: The nucleus of 3I/ATLAS is roughly a million times more massive than 1I/`Oumuamua and a thousand times more massive than 2I/Borisov, while moving faster than both (see here and here). There is not enough rocky material in interstellar space to deliver a rock of this mass once per decade to the inner solar system (see here). This suggests that 3I/ATLAS may have targeted the inner solar system rather than was drawn at random from the reservoir of interstellar rocks. 4. P<0.001: During July and August as well as through November of 2025, 3I/ATLAS displayed a sunward jet (anti-tail) that is not an optical illusion from geometric perspective, unlike thousands of known comets (see here). The HiRISE image taken at closest approach of 3I/ATLAS to Mars, confirmed a glowing extension ahead of 3I/ATLAS along the direction of motion (see here). For a technological object, a beam of light or particles might be used to mitigate the risk from micrometeorites or rocks that could impact its surface at a relative speed of order 60 kilometers per second and release a thousand times more energy per unit mass than explosives. 5. P<0.001: The gas plume surrounding 3I/ATLAS contains much more nickel than iron as found in industrially-produced nickel alloys, and a nickel to cyanide ratio that is orders of magnitude larger than for thousands of known comets, including 2I/Borisov (see here). This might indicate an artificial origin of these unusual abundances. 6. P=0.002: The retrograde trajectory of 3I/ATLAS is aligned to within 5 degrees with the ecliptic plane of the planets around the Sun (see here). This suggests that the trajectory may have been designed. II. Medium anomalies, which could be a statistical fluke: 1. P=0.006: 3I/ATLAS arrived from a direction coincident with the radio “Wow! Signal” to within 9 degrees (see here). 2. P<0.01: 3I/ATLAS shows extreme negative polarization, unprecedented for all known comets, including 2I/Borisov (see here). This unusual polarization may be related to its unusual anti-tail. III. Minor anomalies, which could potentially be explained by a unique origin: 1. P<0.1: The gas plume surrounding 3I/ATLAS contains only 4% water by mass, a dominant constituent of familiar solar-system comets (see here). The plume might have resulted from the sunlight releasing the ices and dust that accumulated on the surface of a technological object during its journey through the cold interstellar medium. 2. P<0.1: Near perihelion, 3I/ATLAS brightened faster than any known comet and was bluer than the Sun (see here). This might be a signature that its engine turned on. 3. P<0.1: 3I/ATLAS exhibits sunward and anti-solar jets which require an unreasonably large surface area for a natural comet in order to absorb enough sunlight needed to sublimate enough ice to feed the mass flux of these jets (as calculated here). The jets might originate from technological thrusters. 4. P<0.1: The tightly-collimated jets from 3I/ATLAS maintain orientation across a million kilometers in multiple directions relative to the Sun despite its measured rotation. The jets might originate from technological thrusters. 5. P<0.1: Near perihelion 3I/ATLAS exhibits non-gravitational acceleration which requires massive evaporation for a natural comet (as calculated here), whereas preliminary images indicate that the object maintained its integrity and did not break up (as discussed here). Instead, the acceleration might have been produced by an engine. *** The probability for the combined occurrence of multiple independent anomalies is the product of their individual probabilities. From the above list, it is apparent that 3I/ATLAS is an extremely rare and mysterious object, especially if it happens to be a natural comet as argued by NASA officials at the press conference on November 19, 2025 (accessible here). In an interview on NewsNation last night (accessible here), Natasha Zouves asked me what data am I most looking for in the coming weeks. I explained that a spectroscopic measurement of the speed and composition of the jets of 3I/ATLAS would reveal whether they stem from the sublimation of pockets of ice on the surface of a rock or from technological thrusters. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

Trajectory of 3I/ATLAS with positions of the planets on November 22, 2025. (Credit: NASA/JPL)Let us suppose, hypothetically, that the interstellar object 3I/ATLAS is a mothership that was designed to seed Jupiter with technological devices. What would be the largest distance from Jupiter that this interstellar gardener should arrive at? For that purpose, 3I/ATLAS must arrive within Jupiter’s radius of gravitational influence — the so-called Hill radius, inside of which Jupiter’s gravity overcomes the gravitational tide from the Sun. Interior to that radius, Jupiter’s gravity wins over the Sun’s gravity and can keep low-speed orbiters bound without the Sun ripping them away. The Lagrange points L1 and L2 of force equilibrium are located at the Hill radius and are ideal locations for technological satellites, since orbital corrections and fuel requirements are at minimal there. Jupiter’s Hill radius is given by the equation: H=R*(m/3M)^{1/3}, where R is Jupiter’s distance from the Sun at the particular time of interest, m is Jupiter’s mass and M is the Sun’s mass. 3I/ATLAS is expected to get to its closest distance from Jupiter on March 16, 2026. The Jupiter-Sun separation on that date will be R=783.8 million kilometers. Substituting this value in the above equation together with (m/3M)^{1/3}=0.06826, yields the Hill radius of Jupiter on March 16, 2026: H=53.502 million kilometers. The distance of closest approach of 3I/ATLAS to Jupiter is calculated by NASA’s JPL Horizons code based on orbital data gathered by about 230 observatories regarding its motion in the sky. This data includes the recently measured non-gravitational acceleration of 3I/ATLAS during perihelion, leading JPL Horizons to forecast that on March 16, 2026 3I/ATLAS will arrive at the following minimum distance from Jupiter: Min{D}= 53.445 (+/- 0.06) million kilometers What an extraordinary coincidence. The values of H and min{D} are identical within one standard deviation of 0.06 million kilometers. The near coincidence of these numbers was brought to my attention by Steve Fairfax. The measured value of the non-gravitational acceleration of 3I/ATLAS, acquired during the month-long passage of 3I/ATLAS near perihelion, changed the value of min{D} at a level of 0.1 million kilometers. This magnitude of displacement in the minimum distance of 3I/ATLAS from Jupiter results from the measured non-gravitational acceleration value of 5x10^{-7} au per day squared as reported here, after the month-long perihelion crossing (where au is the Earth-Sun separation). In other words, the non-gravitational acceleration introduced a small course correction of exactly the magnitude needed to bring the minimum distance of 3I/ATLAS from Jupiter to the value of Jupiter’s Hill radius. 3I/ATLAS would have missed the edge of the Hill sphere otherwise. This suggests that the level of non-gravitational acceleration was finely tuned to result in min{D}=H and bring 3I/ATLAS exactly to the radius of Jupiter’s gravitational influence. If 3I/ATLAS is technological in origin, it might have fine-tuned its trajectory with the help of thrusters so as to arrive at Jupiter’s Hill radius. In that case, the multiple jets observed around 3I/ATLAS in its post-perihelion images (as reported here, here, here and here) might have been used for the slight orbit correction needed to result in min{D}=H. The optimal time for any such maneuver is close to perihelion when a spacecraft can take advantage of the gravitational assist from the Sun (as pointed out here). In addition, 3I/ATLAS arrived at perihelion while being hidden behind the Sun for Earth-based observatories. We therefore do not know whether it just maneuvered slightly to satisfy min{D}=H or also released technological devices near perihelion. How statistically rare is the coincidence between the values of min{D} and H? A margin of 0.06 out of 53.5 million kilometers corresponds to a coincidence of one part in a thousand. But given the full diameter of Jupiter’s orbit around the Sun, this coincidence amounts to one part in 26,000. If 3I/ATLAS were to deposit devices within the Hill sphere of Jupiter on March 16, 2026, these devices would need to fire their engines in order to cancel out the high speed of 3I/ATLAS relative to Jupiter, which is 65.9 kilometers per second. The escape speed from Jupiter’s gravitational potential well at H=53.5 million kilometers is just 2.2 kilometers per second. Any new objects orbiting Jupiter after the passage of 3I/ATLAS, could be identified by the Juno spacecraft (as discussed here) or by other human-made orbiters around Jupiter. If we find technological satellites of Jupiter that we did not send, it would imply that Jupiter is of interest to an extraterrestrial civilization. Not finding similar gadgets near Earth might be disappointing because it would suggest that our interstellar guest is not interested in us. Not only that we are not at the center of the Solar system, but we are also not at the center of attention of our cosmic neighborhood. This will deliver a blow to our ego, akin to attending a party where nobody is interested in dancing with us. Perhaps this is because the human species arrived late to the party — only a few million years ago, whereas Jupiter — the biggest planet in the Solar system, was visible to the senders of 3I/ATLAS when the mission was launched billions of years ago. After all, most stars formed billions of years before the Sun and it would take 3I/ATLAS a billion years to cross the Milky-Way disk. Here’s hoping that when our own interstellar spacecraft reach their target planetary systems, the press conference held by space officials there will not refer to our technological products as “definitely comets!”, based on the ices and dust that accumulated on their surface during their journey through the cold interstellar medium. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

Newly-Discovered Sideways Lines Are Likely a Satellite Streak or Otherwise a Hint for the Release of Smaller Objects by 3I/ATLASA stacked image of 3I/ATLAS based on 20 exposures of 100 seconds each, taken at 4:15 UTC on November 20, 2025. The displayed field has dimensions of 16.7 arcminutes on a side, equivalent to 1.6 million kilometers at the 3I/ATLAS distance of 326 million kilometers. The direction of the Sun is towards the lower left (opposite to the arrow in the middle panel). The image shows two narrow lines directed sideways from the 3I/ATLAS-Sun axis and creating a X-pattern with the tail and anti-tail along that axis. (Credit: M. Jäger, G. Rhemann, and E. Prosperi)Today a new image of the interstellar object 3I/ATLAS was taken by M. Jäger, G. Rhemann, and E. Prosperi and reported here. The image stacks 20 exposures of 100 seconds each, observed at 4:15 UTC on November 20, 2025. The displayed field has dimensions of 16.7 arcminutes on a side, equivalent to 1.6 million kilometers at the 3I/ATLAS distance of 326 million kilometers from Earth. The image shows two narrow jets directed opposite to each other and oriented vertically from the 3I/ATLAS-Sun axis. Together with the tail and anti-tail along this axis, the sideways lines constitute an X-shaped pattern. They extend out to a distance of about a million kilometers from 3I/ATLAS. The simplest interpretation is that these lines are the streak of an Earth-based communication satellite which coincidentally intersected 3I/ATLAS in projection in the sky for a few seconds. There is another line near the bottom of the image, also likely to be a satellite streak. If future images will confirm the reality of these lines as associated with 3I/ATLAS, then these sideways jets will raise two questions: 1. Why are the sideways jets so straight and narrow, resembling thin lines, given that 3I/ATLAS was reported here to rotate with a 16.16-hour period? Given the typical thermal speed of 400 meters per second for sublimated volatiles at the current distance of 3I/ATLAS from the Sun, the rotation of 3I/ATLAS should have introduced gaps or wiggles in the jets on a length-scale of order tens of thousands of kilometers. Such periodic features are not apparent in the new image. 2. Why are the two sideways jets oriented vertically to the tail and anti-tail associated with the 3I/ATLAS-Sun axis? We expect outgassing to emerge from the surface of a rock when it faces the Sun. The resulting gas or dust are expected to be pushed away from the Sun by radiation pressure and the solar wind. Both processes favor the 3I/ATLAS-Sun axis as the line of symmetry and not the vertical direction traced by the sideways jets. If not a satellite streak, these straight and narrow sideways-jets is that they are lines highlighting the trail of gas or dust associated with the linear path of small mini-objects that departed from 3I/ATLAS. If the mini-objects started their journey near perihelion — at closest approach of 3I/ATLAS to the Sun on October 29, 2025, they traversed a distance of a million kilometers in 22 days. This corresponds to a speed of 500 meters per second relative to 3I/ATLAS. The mini-objects could either be pieces of ice that broke apart from the surface of a natural comet nucleus or small probes that were released from a technological mothership. By monitoring these components in the coming weeks, we should be able to distinguish the two interpretations. The release of sub-components by 3I/ATLAS can also explain the X-shape of the glow around 3I/ATLAS in its HiRISE image at closest approach to Mars (as discussed here). Since this image was taken on October 2, 2025, it represents the early stage of the break-up of 3I/ATLAS into multiple components — extending only out to a few thousand kilometers at that time. If the break-up started close to Mars two months ago, the ejection speed of the sub-components needs to be about 200 meters per second. The required velocity kick, formulated in rocketry as Delta-V, is very reasonable for the thrust enable by chemical propulsion. The Sun’s tidal force across the diameter of 3I/ATLAS is too weak to yield this velocity kick over the related period of time. A 3.2 second exposure of 3I/ATLAS on October 2, 2025 by the HiRISE camera onboard the Mars Reconnaissance Orbiter. The directions of the Sun and 3I/ATLAS’ motion are indicated by arrows. The image shows an X-pattern similar to that found in the new image taken on November 20, 2025. (Credit: NASA/JPL-Caltech/University of Arizona)The fundamental question to address in the coming weeks is whether these smaller objects are real and not simply an artifact of a satellite streak, and if real— are they natural or technological in origin? *** Below are three uplifting letters that I had received this afternoon: Letter 1 “Dear Dr. Loeb, I hope this message finds you well. My name is Andrea Forsythe, and I’m writing from Caruthersville, Missouri — a small town in the Bootheel where I work as a Marketing Manager at our local casino. It may seem worlds apart from astrophysics, but your work has reached into my life in extraordinary ways. I wanted to personally thank you for the incredible amount of wonder, curiosity, and open-mindedness you’ve inspired in me since the beginning of the discovery of 3I/ATLAS. What moved me most wasn’t just the object itself — it was you. It was the way someone with your breadth of achievements and accolades could still lead with humility, openness, and a willingness to ask the questions others shy away from. You consistently choose honesty over ego, exploration over certainty, and humanity over reputation. Watching you do that so publicly and so gracefully has changed me. And the impact didn’t stop with me. Over the past couple of months, as my daughter Payton and I have followed this cosmic mystery together, something remarkable happened. She is a high school senior this year, standing at the crossroads of who she will become. Through our long conversations — sparked by your work and your courage to explore the unknown — she found a new sense of purpose. Payton has now decided to pursue a career in Anthropology, driven by the same curiosity, wonder, and openness you model so effortlessly. Your influence reached across the cosmos and into our home, shifting not only my perspective, but the trajectory of her future. For that, I cannot thank you enough. The spark you lit wasn’t only about the universe. It reached into every part of my life — especially the places I’ve kept guarded because of uncertainty. You reminded me that wonder is not naïve, that humility is strength, and that being open to the unknown is one of the greatest gifts a person can give themselves. I also want to share a line from your recent paper that I believe should be echoed around the world. It has stayed with me every moment since I read it: “Life is worth living if we allow for the unexpected to surprise us.”  — Avi Loeb Thank you, again, for your work, your courage, and your humility. You’ve changed how I look at the universe, how I look at myself, and even how my daughter looks at her future. With deep gratitude, Andrea Forsythe Caruthersville, Missouri” Letter 2 “Dear Dr. Loeb, I hope this email finds you well. I am an attorney based in Florida, with space law and science as my personal hobbies. Living on Florida’s Space Coast, I’ve grown up surrounded by aerospace; my family across generations has been deeply involved, from working on the Manhattan Project to working intimately with NASA on shuttle launches and the STS programs. This heritage has made me a lifelong fan of NASA, complete with a hefty space collection in my office. I wanted to thank you for your remarkable courage in taking the middle path on topics like 3I/Atlas, despite attacks from both sides. Your evidence-based openness has inspired an entire category of humanity to restore faith, awe, and inspiration in science, countering the distrust fueled by a variety of factors including paternalistic gatekeeping. This type of evidence-based courage is absolutely necessary for furthering science exponentially and for finding meaning in a future of abundance, where science becomes a key outlet for human passion and curiosity, synergistically with AI. This inspiration comes at a critical time, as public support for science seems to be on the decline and control over the direction of science appears to have been heavily consolidated to only a few. The tragedy of modern institutional tenure aside, almost 75% of all U.S. clinical trials in medicine are paid for by private companies, and these companies tend not to fund research that fails to accord with preferred financial outcomes. It is no surprise that public trust in medical scientists has significantly eroded. According to Pew Research Center surveys, confidence in medical scientists to act in the public’s best interest dropped from 87% in January 2020 to around 77% by 2023, with only 29% expressing a “great deal” of confidence in recent years. This decline is mirrored in the medical field, where the percentage of U.S. physicians primarily engaged in research has plummeted from 4.6% in 1985 to just 1.5% by 2019, signaling a broader disengagement that threatens innovation. Furthermore, as I believe you have stated before, the rising average age of Nobel Prize winners in Physics underscores a march toward stagnation: early 20th-century laureates averaged around 55 years old, but today it’s climbed to about 65–67, reflecting risk-averse cultures that delay bold breakthroughs. Scientific innovation has been under attack. I was deeply disappointed with NASA’s broadcast yesterday, which took a conservative approach, repeating the “trust the experts over the data” mantra that’s eroding public trust while failing to address nearly all of the 12 anomalies. We need more Galileo- and Loeb-like leaders at the forefront and in positions of power. It’s a human imperative at this point. Thank you again for leading the way. If you or the Galileo Project ever need legal advice or legal research, I’d be happy to volunteer. Best regards, Andrew David Easler” Letter 3 “Dear Professor Loeb, My name is Sergio and I’m from Italy. I am 40 years old and I always been terrible in science, physics and all these complicated subjects. Nevertheless, since I was a kid, I always looked at the stars and always had this feeling that made me wonder about the universe, our planet, why we are here and are we alone? Now that I’m old I want to thank you because this feeling is still very much alive thanks to you, you are the rockstar of scientists! Keep doing your job and keep asking questions please, one day we will have the answers or maybe not but since there are people like you, we will never stop learning.” ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

A 3.2 second exposure of 3I/ATLAS on October 2, 2025 by the HiRISE camera onboard the Mars Reconnaissance Orbiter. The directions of the Sun and 3I/ATLAS’ motion are indicated by arrows. (Credit: NASA/JPL-Caltech/University of Arizona)The newly released HiRISE image of the interstellar object 3I/ATLAS available here, shows an extension of the glowing plume in the direction of motion ahead of 3I/ATLAS. It appears like there is something preceding the object that was previously confused with being in the direction of the Sun but is actually in the direction of motion. In previous images like the Hubble Space Telescope image here, the two directions were similar when 3I/ATLAS was heading towards the Sun from far away. It is easy to explain a plume of gas and dust extended towards the Sun as a result of the illumination of pockets of ice by sunlight or away from the Sun as a result of radiation pressure or the solar wind. It is also possible to explain a trailing stream that the object leaves behind as the drag on the solar wind slows it down relative to the object. But it is much more difficult to account for a plume extended perpendicular to the direction of the Sun and ahead of the object. The scale of the extension in the HiRISE image is ~3,000 km. At the typical thermal speed of volatiles which sublimate from the surface of a natural comet, it takes only a day to cross that distance.Could this be a technological signature of illuminating or clearing the path from any hazardous micrometeorites that may cause damage to a technological object? For now, we can only hope that the mysteries of 3I/ATLAS will be cleared by data in the next few weeks when large ground-based telescopes as well as the Hubble and Webb telescopes will be able to characterize the jets of 3I/ATLAS by measuring their composition, speed and mass loading rate. These details will inform us without a doubt whether the jets are produced by natural pockets of ice that are warmed by sunlight or by technological thrusters. Upcoming data can be used to search for any additional objects that came out of 3I/ATLAS, be it fragments of ice for a natural object or mini-probes for a technological object. This morning, I received the following inspiring messages. Letter 1 “Dear Mr Avi Loeb… Never in a million years did I think I would be in a position to message someone as high up in the hierarchy of speaking the ‘truth’ as you… You are such an inspiration to many…. You haven’t backed down… You have used your words…your knowledge…your wisdom…very carefully…and you have empowered many people to stand by their own beliefs… I just want to thank you so much for the dedication…the passion…and the truth that you put into your work… I am looking forward to hearing more about your research… I wish you well…all my support… From one of your biggest fans… Kayleigh” Letter 2 “Dear Professor Loeb, I hope this message finds you well. I wanted to write to you after following your work on 3I/ATLAS these past months, and especially after yesterday’s NASA briefing. Although I am not a scientist by profession, I have a deep interest in astrophysics and in how we interpret evidence when something unfamiliar enters our Solar System. Your approach to 3I/ATLAS has been a source of clarity and intellectual honesty in a time when many prefer convenient explanations over confronting genuine anomalies. What I appreciate most is that your arguments are not speculative; they are calculated. You consistently present the numbers, the physics, and the probabilities without forcing a conclusion. As a non-scientist, I can still recognize how rare that is. You unite rigor with openness, which is exactly what scientific curiosity should be. I have been following the unusual features of 3I/ATLAS closely: the sunward jet that persists far longer than natural models predict, the highly unusual nickel-to-iron ratios, the unprecedented negative polarization, the extreme CO₂ dominance, and the improbably aligned trajectory through the inner Solar System. Even without a scientific background, it is clear that these are not trivial details, and your willingness to treat them seriously is something I deeply respect. I must admit that yesterday’s NASA presentation left me uneasy. The absence of the long-anticipated HiRISE images, along with explanations that seemed more like public-relations language than scientific clarity, reminded me of how important it is to have independent voices who are willing to ask the difficult questions. Your calm, measured commentary stands in sharp contrast to the defensiveness we sometimes see in institutional communication. I simply want to thank you. Your work has reignited my curiosity, and more importantly it restored my belief that science can still be courageous. You have a remarkable ability to speak plainly without oversimplifying, to explore the unknown without sensationalizing it, and to hold fast to the principles of evidence and inquiry even when criticism is loud. Please continue exactly as you are. Your voice is inspiring to many of us who are watching closely and hoping that the scientific community can remain open-minded when faced with something genuinely new. With respect and gratitude, Giovanni Carbonella from Belgium” Letter 3 “Dear Professor Loeb, My name is Reuben Daniel, writing from India. I’ve followed the evolution of the 3I Atlas not just as a scientific project, but as a philosophical attempt to re anchor humanity in a universe we barely understand. Most scientific work expands knowledge; very little expands perspective. Your work does both and that is what compels me to reach out. In the past months, I’ve read through every accessible discussion, interview, analysis, and fragment of information surrounding the Atlas. What drew me in was not just the possibility of new discoveries, but the underlying principle, that humanity must investigate its uncertainties with rigor rather than imagination, with humility rather than spectacle. The 3I Atlas, to me, is more than a map of objects or anomalies. It is a map of intellectual discipline, a reminder that truth is not found through authority or noise, but through patterns, data, and the willingness to confront the uncomfortable. At a time when societies are shaped by opinion more than evidence, this kind of work becomes quietly revolutionary. Coming from India, a place where multiple worlds, beliefs, and narratives coexist, I’ve always been fascinated by how humans make meaning out of ignorance. The questions you pursue have existed in mythology, philosophy, and religion for thousands of years. But for the first time, we stand in an era where these questions can finally be approached with scientific instrumentation rather than mythic intuition. Your research, in many ways, represents that transition. If the Atlas or your broader investigations ever require assistance analytical, technical, coordination based, or exploratory, I would be honored to contribute from here. I bring a mindset shaped by curiosity, skepticism, and a strong sense of the social responsibility attached to scientific transparency. Humanity has always looked upward, but rarely with clarity. You are attempting to give the world something it has never had: a disciplined framework for investigating the unknown. Thank you for the work you are doing professor and for reminding people across the world that progress begins not with answers, but with better questions. With respect, Reuben Daniel” Letter 4 “Dear Professor Loeb, Thank you for your latest analysis of NASA’s press event and for continuing to approach 3I/ATLAS with scientific honesty and independence. Many of us appreciate that you do not force a natural explanation where the data does not yet support one. Your openness to unresolved anomalies and your persistence in following the evidence make a real difference. Please continue your work. Many people value your voice and rely on your careful, unbiased approach so that nothing important is overlooked. With appreciation, Eric Schmidt” Letter 5 “Dear Professor Loeb, I am writing to express my deep appreciation for your work, your courage, and your open-mindedness in exploring the mystery of the interstellar object 3I/ATLAS. For months I have been following every one of your posts, analyses, and interviews, and what you have done has become not only an intellectual inspiration for me, but also a genuine emotional experience. Reading your articles on Medium often feels like going through the chapters of an absorbing thriller — one that keeps a person awake late into the night. This year, it is you who has brought me the greatest fascination with our place in the Universe. Your willingness to consider hypotheses that lie outside the comfort zone of mainstream science is something extraordinarily rare among contemporary researchers. The anomalies associated with 3I/ATLAS are astonishing. The fact that they all appear simultaneously makes me feel that we are witnessing something historic. Your scientific approach — rooted in evidence rather than in attachment to established dogmas — is invaluable to me. I have always loved science fiction and have read nearly all of its major works, and what is happening now reminds me very strongly of the atmosphere of Arthur C. Clarke’s Rendezvous with Rama. The difference is simply that I am not reading about this in a book — I am watching it unfold in reality. When 3I/ATLAS began glowing an intense blue at perihelion, I felt something I had never felt before: a mixture of awe and concern. It made me think of the film Don’t Look Up and the character played by Leonardo DiCaprio — a man who saw what others refused to acknowledge. In that moment, I genuinely began to wonder whether the trajectory of 3I/ATLAS would remain stable. I would like to share something personal as well. I am a father to a nine-year-old daughter, whom I have inspired with a passion for space thanks to your work. Every day I tell her about your latest posts, the surprising anomalies, and the possibilities surrounding 3I/ATLAS. I see her curiosity growing week by week, and her questions becoming deeper. This is because of you. Perhaps you have planted in her the seed of a future astrophysicist. I also watched your conversation with Joe Rogan, and I was genuinely impressed by your calm, rational approach and your intellectual integrity. It is disappointing to see how many in the scientific community dismiss anything that lies outside conventional assumptions — often without providing any substantive counterargument. None of your critics have been able to address the twelve anomalies you have described, yet they persist in their position. Sometimes I feel that even if 3I/ATLAS changed course and headed straight toward Earth, some of them would still insist that it was just a comet. I admire your bravery and intellectual honesty. I believe that future generations will look back on this period as a turning point — a moment when someone dared to ask the questions others were afraid even to form. I sincerely hope that through your work, your determination, and your scientific insight, the mystery of 3I/ATLAS will one day be fully understood. With profound respect and gratitude, Adam Dziedzic” ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

The MeerKAT radio telescope in South Africa. (Credit: NRF/SARAO)The MeerKAT radio telescope in South Africa conducted on November 5, 2025 a search for narrowband radio transmission from the interstellar object 3I/ATLAS using the commensal backend BLUSE suitable for a real-time search for radio technological signatures. As reported here, a total of 23,689 signals were detected; however, all were determined to not be spatially consistent with the position of 3I/ATLAS and thus were likely caused by human-made radio frequency interference. From these observations, the observers established a detection limit of 0.17 Watts over the frequency range of 900 to 1670 megahertz, approximately equivalent to the power output of a mobile phone handset at the distance to 3I/ATLAS, which was 334 million kilometers at the time. Today at 3PM ET, NASA will broadcast a press conference here in which new data from ground-based and space-based observations will be publicly released for the first time after the government shutdown. The data will include images of 3I/ATLAS when the object came within 29 million kilometers from Mars on October 3, 2025. At that time, the HiRISE camera onboard the Mars Reconnaissance Orbiter could have imaged 3I/ATLAS with a pixel resolution of 30 kilometers. The brightest pixel in the HiRISE image would constrain the nucleus size and reveal the geometry of the glow around it. It is also interesting to check if there is any evidence for new objects that either accompanied 3I/ATLAS or left it towards Mars. They could imply fragments from an iceberg that broke up or mini-probes released by a technological mothership. The fundamental question looming in the background remains: “Is 3I/ATLAS a rare comet of a type never seen before or a technological object?” So far, 3I/ATLAS did not display any unambiguous technological signatures, such as a major maneuver, artificial light or transmission of a radio signal. Below is a recap of the anomalies of 3I/ATLAS that could flag a technological signature: 1. Its trajectory opposite to the direction of motion of the planets is aligned to within five degrees with the ecliptic plane of the planets around the Sun, with a likelihood of 0.2 per cent (see here). This suggests that the trajectory may have been designed for a reconnaissance purpose. 2. During July and August as well as in early November of 2025, it displayed a sunward jet (anti-tail) that is not an optical illusion from geometric perspective, unlike familiar comets (see here). This might be a technological signature. 3. Its nucleus is about a million times more massive than 1I/`Oumuamua, an interstellar object discovered in 2017, and a thousand times more massive than 2I/Borisov, discovered in 2019, while moving faster than both, altogether with a likelihood of less than 0.1 per cent (see here and here). This suggests that it may have targeted the inner solar system rather than being drawn from the reservoir of icy rocks. 4. Its arrival time was fine-tuned to bring it within tens of millions of kilometers from Mars, Venus and Jupiter and be unobservable from Earth at perihelion, with a likelihood of 0.005 per cent (see here). 5. Its gas plume contains much more nickel than iron (as found in industrially-produced nickel alloys) and a nickel to cyanide ratio that is orders of magnitude larger than that of all known comets, including 2I/Borisov, with a likelihood below 1 per cent (see here). This may be a signature of industrial production of its surface. 6. Its gas plume contains only 4 per cent water by mass, a primary constituent of familiar comets (see here). 7. It shows extreme negative polarization of light, unprecedented for all known comets, including 2I/Borisov, with a likelihood below 1 per cent (see here). This might be a technological signature. 8. It arrived from a direction coincident with the radio ‘Wow! Signal’ to within 9 degrees, with a likelihood of 0.6 per cent (see here). This might imply that the `Wow! Signal’ may have originated from it or its senders. 9. Near perihelion, it brightened faster than any known comet and was bluer than the Sun (see here). Perhaps this is a signature that its engine turned on. 10. It exhibits jets in the direction of the Sun and opposite to it, which require an unreasonably large surface area in order to absorb enough sunlight needed to sublimate enough ice to feed the mass flux of these jets (as calculated here). Perhaps the jets originate from technological thrusters. 11. Near perihelion it exhibits non-gravitational acceleration which requires massive evaporation, whereas preliminary images indicate that the object maintained its integrity and did not break up (as discussed here). Perhaps the acceleration was produced by an engine. 12. Its tightly-collimated jets maintain orientation across a million kilometers in multiple directions relative to the Sun despite its measured rotation (as discussed here). This might imply that they are used for navigation or associated with the release of mini-probes from a mothership. If an interstellar object happens to be technological, it could pose a threat to humanity. A few months ago, I described the `Loeb Scale’ (as quantified here and here) — where a rank of `0' implies a natural comet and a rank of `10' corresponds to alien technology that threatens humanity. We do not have a response protocol for alien technology, but after the first encounter — as long as we survive it — there will be political will to invest trillions of dollars in a warning system of interceptors that take close-up photos of anomalous interstellar objects. 3I/ATLAS is expected to arrive closest to Earth at a distance of 269 million kilometers on December 19, 2025. Let us hope that it will not deliver us any unwanted gifts for the holidays. Among the unexpected gifts I received today was the following uplifting message: “Mr. Loeb, I have been following your work, interviews and published papers since September and just wanted to express to you my immense gratitude for you! You are a rare and incredible person as you’re not only a phenomenally brilliant scientist, but such a humble person who truly desires to share truth with all people, not for your own benefit but for the benefit of all people. Your determination in the face of great challenges and undeserved scrutiny has been remarkable and admirable to witness. You have reignited my love for and fascination with science. I’m a Realtor/regular working Mom and don’t work in science or engineering but every day I look forward to checking your publications. I have to admit that for someone like me, in full transparency, many of the high level (yet fascinating) concepts/details in your papers require a much higher level of thought than I possess, and yet you somehow find a way to make the key points understandable for us non-scientists (which is no easy task lol). Even more important than science, you’ve taught me that there are still truly good people in the world who refuse to be corrupted by power, riches or pride. Thank you for sharing your brilliance, carrying yourself with grace, being courageous (when I’m sure it would be much much easier not to), and for sharing truth and making it accessible to all people. Your incredible work will be remembered throughout history! Warm regards, Angelique Jones” ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

An image of 3I/ATLAS, combining 24 exposures of 60 seconds each with a 0.2-meter telescope (Celestron EdgeHD 800) in New Mexico, USA between 11:53–12:23 UTC on November 16, 2025. The image shows multiple jets both towards and away from the Sun. The sunward direction is pointing to the lower left corner. (Credit: Satoru Murata)As I explained in an interview with Peter Doocy on “The Sunday Briefing” of Fox News yesterday (accessible here), the foundation of science is based on the humility to learn, not the arrogance of expertise. When comet experts argued that 3I/ATLAS must be a familiar water-rich comet as soon as it was discovered on July 1, 2025, they behaved like artificial intelligence systems which reflect their training data sets. For decades, the data set that established comet expertise included icy rocks in the solar system. My point is simple. Humanity launched technological objects to space and we must add them to the training data set of comet experts when studying interstellar objects. On January 2, 2025, the Minor Planet Center — officiated by the International Astronomical Union to catalog space objects, identified a “near-Earth asteroid”. A day later, the officials realized that this “asteroid” follows the trajectory of the Tesla Roadster car, launched to space by SpaceX in 2018 as a dummy payload on the Falcon Heavy rocket. They immediately removed the object from their asteroid catalog, realizing that it is not a rock but rather a car. Elon Musk is probably not the most accomplished space entrepreneur in the Milky-Way over the past 13.8 billion years. There are about a hundred billion stars like the Sun in the Milky-Way, and roughly a tenth of them host a habitable Earth-size planet. If you roll the dice on billions of Earth-Sun analogs, surely you could get more accomplished space entrepreneurs on some exo-planets. Most stars are billions of years older than the Sun, and during a billion years our Voyager spacecraft with its 1970s technologies can reach the opposite side of the Galactic disk. This implies that there was plenty of time for interstellar artifacts, potentially more advanced than Voyager or the Tesla Roadster car, to reach the Solar system from interstellar space. Would comet experts recognize these visitors as technological artifacts if their training data set includes only icy rocks? I do not think so. To broaden the perspective, I identified the following twelve anomalies of 3I/ATLAS: 1. Its retrograde trajectory is aligned to within 5 degrees with the ecliptic plane of the planets around the Sun, with a likelihood of 0.2% (see here). 2. During July and August as well as in early November of 2025, it displayed a sunward jet (anti-tail) that is not an optical illusion from geometric perspective, unlike familiar comets (see here). 3. Its nucleus is about a million times more massive than 1I/`Oumuamua and a thousand times more massive than 2I/Borisov, while moving faster than both, altogether with a likelihood of less than 0.1% (see here and here). 4. Its arrival time was fine-tuned to bring it within tens of millions of kilometers from Mars, Venus and Jupiter and be unobservable from Earth at perihelion, with a likelihood of 0.005% (see here). 5. Its gas plume contains much more nickel than iron (as found in industrially-produced nickel alloys) and a nickel to cyanide ratio that is orders of magnitude larger than that of all known comets, including 2I/Borisov, with a likelihood below 1% (see here). 6. Its gas plume contains only 4% water by mass, a primary constituent of familiar comets (see here). 7. It shows extreme negative polarization, unprecedented for all known comets, including 2I/Borisov, with a likelihood below 1% (see here). 8. It arrived from a direction coincident with the radio “Wow! Signal” to within 9 degrees, with a likelihood of 0.6% (see here). 9. Near perihelion, it brightened faster than any known comet and was bluer than the Sun (see here). 10. It exhibits sunward and anti-solar jets which require an unreasonably large surface area in order to absorb enough sunlight needed to sublimate enough ice to feed the mass flux of these jets (as calculated here). 11. Near perihelion it exhibits non-gravitational acceleration which requires massive evaporation of at least 13% of its mass (as calculated here), whereas preliminary images indicate that the object maintained its integrity and did not break up (as discussed here). 12. Its tightly-collimated jets maintain orientation across a million kilometers in multiple directions relative to the Sun despite its measured rotation. In ignoring these anomalies, comet experts miss two important opportunities. First, the public loves to view science as work in progress rather than a finished product. Collecting evidence is a learning experience akin to the work of a detective. It sometimes unravels a sobering truth that was not anticipated since nature is more imaginative than we are. This was certainly the case when quantum mechanics was discovered a century ago and revealed a physical reality that was counterintuitive to Albert Einstein. Despite lessons from history, present-day scientists minimize the risk to their reputation by not sharing error-corrections from data and conversing with the public only once they know the final answer. In this risk-averse intellectual climate, they inform the public of their final findings in press conferences where they behave like lecturers in the classroom. The audience is made aware of what it needs to know. By minimizing the risk to their reputation, scientists promote the impression that science is an occupation of the intellectual elite. But the truth is that the mainstream of science is routinely wrong. Einstein argued between 1935 and 1940 that quantum mechanics does not have “spooky action at a distance” and that black holes or gravitational waves do not exist. The popular idea of supersymmetry was ruled out by CERN’s Large Hadron Collider. In addition, after four decades of occupying centerstage in mainstream theoretical physics — string theory is no closer to making unique predictions that can be tested experimentally. Through my communications about 3I/ATLAS, I convey the notion that science is work in progress. Anomalies offer a multitude of interpretations that are tested by new data that can rule out all but one of them. I receive hundreds of emails from fans every day and many parents write that their children wish to become scientists after seeing me speak in podcasts or on television. Second, the mainstream defined the search for microbes as the highest priority in the 2020 US Decadal Survey of Astronomy and Astrophysics, converging on the allocation of more than ten billion dollars to the Habitable World Observatory and sidelining the search for technological signatures. Even if microbes are far more abundant on exoplanets, it might be easier to identify technological signatures. It therefore makes most sense to hedge our bets and invest billions of dollars in the simultaneous search for both technological and primitive lifeforms. The public is much more passionate about the search for aliens than the search for microbes. Taxpayers fund science and scientists should not sideline the public’s interest when defining research priorities. Remarkably, interstellar objects offer a new opportunity for both the search for primitive and technological lifeforms. We can land on an interstellar rock and return a sample of it to Earth, just as the OSIRIS-REx mission did with the asteroid Bennu. The returned sample may reveal the building blocks of life from another star. But in case the interstellar object happens to be a technological artifact, our learning opportunities would be far greater. The fundamental question after landing on a spacecraft with buttons on its surface would be whether to press any of these buttons. ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article

An image of 3I/ATLAS, taken at 22:06 UTC on November 15, 2025, shows a prominent anti-tail along with two tails. The sunward direction is pointing to the lower left corner. (Credit: Teerasak Thaluang, MPC-051, Rayong, Thailand)As of November 15, 2025, the interstellar object 3I/ATLAS still displays a prominent anti-tail as well as tails, according to a new image released by Teerasak Thaluang from a 0.26-meter telescope in Thailand. The physics behind the anti-tail of 3I/ATLAS is unclear. For a natural comet, it could be associated with the release of giant dust particles with an effective radius of ~100 micrometers (as suggested by David Jewitt and collaborators here and here). These particles are a million times more massive than the typical micrometer-scale dust which scatters sunlight most effectively because it is comparable in size to the wavelength of the radiation. Since the ratio of surface area — which scales as particle radius squared, to mass — which scales as radius cubed, is 100 times smaller for these giant particles relative to their smaller counterparts, they will not be accelerated away from the Sun by radiation pressure as effectively as micrometer dust in familiar comets. However, the amount of mass loss in 100-micrometer particles must be 100 times larger than the corresponding value for micrometer particles in order to produce the same brightness of scattered sunlight. Another possibility is that instead of refractory dust particles that survive solar heating, the scattering of sunlight is produced by fragments of ice which get evaporated before having a chance to turn around and produce a traditional cometary tail away from the Sun (as I suggested with Eric Keto here and here). Finally, there is the more speculative possibility that the anti-tail is a result of technological thrusters which accelerate 3I/ATLAS away from the Sun through tightly collimated jets that penetrate a million kilometers through the Solar wind because of their high speed. Future spectroscopic data will be able to calibrate the outflow speed and distinguish between natural outgassing which results in a characteristic speed of up to a few hundred meters per second and artificial jets which produce speeds above a few kilometers per second. Figuring things out through the collection of data resembles the work of a detective. With the flood of data on 3I/ATLAS in the coming weeks — leading to its closest approach to Earth on December 19, 2025, we should be able to figure out its nature. The public resonates with evidence-based science, as long as the scientists show the humility to learn something new. Here are 4 out of a thousand supportive letters that I have received in recent days: Letter 1 “Dear Professor Loeb, I apologize for yet another message, but I have just watched your conversation with Dr Brian Keating and I would like to write that whether it is a natural object or technological, I am so grateful to you for opening up this amazing curious discussion in science! After seeing all the unfair criticism coming your way, I truly hope that it will be technological just to see what these “experts” will say! However, if it is natural, I will be equally grateful to you for opening up this fascinating discussion, and I have no doubt that there are technological objects out there anyway — definitely yet to be discovered! I feel that it would be narrow-minded to believe that they do not exist. Thank you so much! With best wishes, Aleksandra Tryniecka” Letter 2 “I know that you get many emails these days and I don’t want to take up too much of your time. But I am a software engineer in the video game industry and have grown up very enthusiastically following astro-physics. I truly believe that if Carl Segan were still with us, he would be strongly in your corner and enthusiastic in his support of your position. Not that I can speak for him. I speak for myself. Thank you! Keep it up! Kevin Normann Georgetown, TX, USA” Letter 3: “Dear Professor Loeb, I hope this message finds you well. I’m writing to express my sincere support and admiration for your stance regarding the interstellar visitor 3I/Atlas. As an amateur astronomer and passionate astrophotographer, I’ve followed your work closely and deeply resonate with your commitment to scientific curiosity and intellectual courage. Your openness to unconventional hypotheses is not only refreshing but essential to the health of scientific inquiry. Unfortunately, I’ve experienced firsthand how discussions with mainstream academics often end in marginalization or attempts to assert authority rather than engage in genuine dialogue. This pattern is particularly evident in exchanges I’ve had within certain online communities where such dynamics are quite apparent. I’ve also had similar conversations in private groups with other mainstream professors that further illustrate this tendency. I wanted to let you know that your assertiveness and integrity in the face of criticism are deeply inspiring. Please continue to stand firm in your approach. Your work encourages many of us who believe that science thrives on pluralism, imagination, and respectful debate. Wishing you strength and success in all your future endeavors. Warm regards, Alexandre From Portugal” Letter 4: “Dear Professor Avi Loeb, My name is Rafael, and I want to express my deep gratitude to you. You are undoubtedly the driving force behind science, and your work and passion for the world have inspired me to explore it. Every day, I study our 3rd interstellar object, and you are the only one who can provide me with well-reasoned explanations. While there may be many opinions and criticisms about you, I wonder why I don’t see any numbers or calculations. This lack of seriousness only discourages people from engaging with science. All these scientists have faced criticism: Galileo (heliocentrism) Darwin (evolution) Wegener (continental drift) Marshall (H. pylori) Einstein (relativity). Thank you for your work!” ABOUT THE AUTHOR (Image Credit: Chris Michel, National Academy of Sciences, 2023)Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024. View the full article