Avi Loeb Medium

The Last Universal Common Ancestor for life-as-we-know-it was a complex microbe that may have thrived in the shallow waters of early Earth, when the Moon loomed bigger in the sky as it was closer to Earth. (Image credit: Mark Garlic/Science Source)A new paper that I co-authored with my brilliant postdoc, Devesh Nandal (available here), suggests gratitude to our cosmic fortunes. Put aside your frustrations with terrestrial geopolitics or complaints about your fellow earthlings. Look up at the brightest stars in the night sky. According to the new paper, the real estate near these massive stars has a low value for life in our cosmic neighborhood of the Milky-Way galaxy. As residents of Earth, we are very fortunate to live next to the Sun. This star provided the appropriate amount of heat to maintain life-as-we-know-it for 4.2 billion years. This lifespan was inferred from our Last Universal Common Ancestor, a microbe which enjoyed a diet of hydrogen and carbon dioxide on early Earth, as reported here. The flux of light suitable to support liquid water on the surface of a rocky planet with an atmosphere, defines the habitable zone around any star. In the vicinity of faint dwarf-stars, the habitable zone is closer in. For our nearest red-dwarf neighbor, Proxima Centauri, the habitable zone is about 20 times closer than it is for the Sun. In 2016, a rocky planet was discovered at that separation and named Proxima b. Habitable-zone planets are common around dwarf stars, which are the most abundant and longest-lived population of stars. This raises a major paradox that I discussed in a 2014 paper, published here. Dwarf stars account for about 90% of the stars in the Milky-Way galaxy and the least massive stars among them — down to 0.07 solar masses, outlive the Sun by up to a factor of a thousand. Given these facts: why do we live next to the Sun today rather than next to a common dwarf star in the future? The likely explanation is that dwarf stars, like Proxima Centauri, have winds and flare frequently. Since the habitable zone is closer in, their winds can strip the atmospheres of habitable planets and their intense UV and X-rays flares can sterilize any surface life (as discussed in a 2017 paper I co-authored with my postdoc then, Manasvi Lingam). But what about stars more massive than the Sun? How habitable are their planets? This is the question addressed in the new paper. Massive stars dominate the light output of young stellar populations. This could have been naively interpreted to mean that they are a blessing for life. The habitable zone is farther away from these bright furnaces, potentially containing more planets. However, our paper shows that the strong winds and Ultraviolet emission extend temperate climates on habitable-zone planets to wide orbits where atmospheric retention is difficult. The new paper couples evolutionary tracks of massive stars to climate boundaries and to atmospheric-retention limits, and characterized habitability in three complementary ways: (1) the total time a habitable-zone exists; (2) the longest continuous residence time of a planet in that zone at a fixed orbit; and (3) the maximum number of Earth analogs that can fit inside the habitable zone. These are folded results through the distribution of stellar masses in the Milky-Way galaxy to estimate the inventory of Earth analogs that satisfy the adopted climate and atmosphere-retention filters. Our calculation shows a sharp loss of habitability for stars above 10 solar masses. At a stellar mass of 9 solar masses, habitability persists for 31 million years with characteristic radii that are 74 to 127 times larger than the Earth-Sun separation (AU), whereas at 12 solar masses — habitability becomes a brief and extremely narrow episode, lasting for just a million years at orbital radii between 256 and 263 AU. Beyond a stellar mass of 15 solar masses, there is no habitability possible. Altogether, the Milky-Way inventory of habitable planets is set by lower-mass host stars. Massive stars above 8 solar masses contribute only 0.01% of the total population of habitable-zone planets. In addition, the short lifetime of the habitable zone makes the evolution of complex forms of life less likely around massive stars. On top of the reduced population of habitable planets near massive stars, it is difficult to detect these planets. Their wide orbits make it easier to separate them from their host stars, but the starlight reflected from their surface or their thermal emission amount to a tiny fraction of the total light emitted by the bright star — making their detection impractical even with the most ambitious coronagraph systems, designed to block the starlight. In conclusion, we should be grateful to the Sun for its stable heat supply over billions of years. There is nothing better than a stable partner who keeps you warm and maintains the right distance from you so as not to trigger any harmful effects from its high-energy output. Ecclesiastes 1:9 states: What has been will be again, what has been done will be done again; there is nothing new under the sun. Based on the new paper, these qualities of the Sun are a blessing. The statement “there is nothing new under the sun” will stay valid for the next billion years, before the Sun will brighten up and boil off all liquid water on Earth. Within 7.6 billion years, the envelope of the Sun might swallow the Earth (as calculated here). Nothing good lasts forever, but while habitability lasts — lets all have fun under the Sun and stop fighting with each other. 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Pointings by the Robert C. Byrd Green Bank Telescope in the Galactic Center region around the supermassive black hole, Sagittarius A*, with an overlaid total intensity mosaic of the region at a frequency of 1.28 gigahertz from the MeerKAT radio observatory. The central pointing, labeled as A00, indicates the Galactic center location at l = 0°, b = 0°. (Image credit: K. Perez et al. 2026)The ideal way to map the spacetime around a black hole is by a Global Positioning System (GPS) with a collection of precise clocks travelling through this spacetime. This was my insight in 2003, when I approached the postdoctoral fellow Eric Pfahl and suggested that we write a paper about the feasibility of such a mapping as a test of Albert Einstein’s theory of General Relativity. My idea was to use a population of millisecond pulsars as an array of natural GPS around the supermassive black hole, Sagittarius A*, at the center of the Milky-Way galaxy. We observe massive stars forming out of dense gas in that region and know that these stars are short-lived. The observed star cluster around this 4.3-million-solar-masses black hole should have left neutron star remnants. A neutron star contains about 1.4 solar masses within a diameter of order 24 kilometers, comparable to the length of Manhattan Island. This compact remnant is a relic of progenitor stars more massive than 8 solar masses and resembles a giant atomic nucleus, made of neutrons at nuclear density. Neutron stars can spin up to a limiting rate without breaking-up, corresponding to a period of order half a millisecond (=0.0005 seconds). Their stable rotation makes them excellent clocks with precision of a part in a trillion, comparable to common atomic clocks. The ticking rate of these precise clocks can be detected on the sky, as some neutron stars produce a stable radio beam that is misaligned with the spin axis and sweeps the sky periodically like a lighthouse. They are called radio pulsars. An artist’s illustration of a pulsar, where a radio beam which is misaligned with the spin axis of a neutron star, sweeps the sky periodically like as a lighthouse. (Image credit: Mark Garlick/Science Photo Library)The resulting paper, titled “Probing the Spacetime Around Sagittarius A* With Radio Pulsars”, was published in 2004 and can be found here. It argued that the brightest radio pulsars near Sagittarius A* may be detectable with current telescopes in periodicity searches at radio frequencies near 10 gigahertz, where the effects scattering by interstellar electrons are modest. Long-term timing observations of such a pulsar would clearly reveal its motion around the black hole and potentially show the effects of Einstein’s relativistic gravity. We discussed how pulsar timing can be used to study the spacetime around the central black hole. This proposal was published 22 years ago. On February 10, 2026, a new paper led by Karen Perez (available here) reported the discovery of a millisecond pulsar candidate following the deepest radio search in the Galactic center region, conducted by the Robert C. Byrd Green Bank Telescope. The survey operated in the radio frequency band of 8–12 gigahertz, using data from the Breakthrough Listen initiative. Following a comprehensive periodicity search targeting radio pulsars, the survey was sensitive enough to detect the most luminous pulsars expected in the Galactic center. Among 5282 sources, the researchers identified an interesting pulsar candidate with a 8.19 millisecond period, persistent in time and frequency, and flagged it for follow-up verification. The scarcity of detected radio pulsars near Sagittarius A* reinforces the concern expressed in my original paper that strong scattering by the dense interstellar gas in the Galactic center obscures pulsar signals. Moreover, the extreme orbital acceleration very close the central black hole could distort the periodic signals and make their detection challenging. Scientific progress sometimes occurs at a glacial pace. I am happy to have laid a brick 22 years ago in the construction project that young scientists like Karen Perez are pursuing now. In a recent conversation, I was asked which historic period I would rather live in, given a choice. My response was: “in the future.” When asked “why?,” I explained that I am optimistic that the future will be better than the past thanks to scientific advances. The collapse of stars at the end of their life leads to compact remnants, such as white dwarfs, neutron stars or black holes. This newly processed image from the NASA/ESA Hubble Space Telescope shows the Egg Nebula, a structure of gas and dust created as a Sun-like star approaches the end of its life. This Egg will eventually hatch, revealing a white dwarf at its center. (Image credit: HST/NASA/ESA)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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: Greg Wyatt)Waterfalls are sites where gravity pulls water down a steep cliff. This setup endows the water with rapid motion as it falls down the gravitational potential well. In Albert Einstein’s theory of General Relativity, gravity is the curvature of spacetime and matter could reach the speed of light in highly distorted spacetime. There is no steeper cliff of spacetime than the vicinity of a black hole singularity, where infalling matter reaches the speed of light and the gravitational tide can rip apart any object. Paradoxically, the heating caused by the infall of matter makes some black hole environments the brightest sources of light in the Universe. They are observed all the way to the edge of the observable Universe, when the cosmic clock showed less than a billion years after the Big Bang — merely 7 percent of the current time. The earliest supermassive black hole was discovered by the Webb Telescope 500 million years after the Big Bang in the form of the source CAPERS-LRD-z9 at a cosmological redshift of 9.288. This black hole has a mass of about 40 million solar masses (as reported here). Surrounding galactic gas appears to fall into this black hole like water going down a waterfall. As the gas heats up, it brightens. The resulting luminous quasar appears as a point source of light, so bright that it outshines its host galaxy. (Image credit: Greg Wyatt)The quasar phase at the centers of all galaxies is short lived, lasting for just 10–100 million years. In the 13.8-billion years movie of cosmic history, quasars appear as explosive flashes of light at the centers of galaxies like decorative sprinkles. Their enormous luminosities are sufficient to heat the surrounding gas and eventually expel it out of the gravitational potential well of their host galaxies. The situation resembles a baby eating more and more food from the table until it eventually becomes energetic enough to push the food off the table. This feedback leads to a self-imposed starvation, which truncates the growth of the central black hole. As a result, supermassive black holes grow up to a limiting mass that correlates with the depth of the gravitational potential well of the host galaxy in which they are embedded. (Image credit: Greg Wyatt)Lower mass black holes form as a result of the collapse of the core of a massive star after it consumes its nuclear fuel and loses pressure support against gravity. The cosmic waterfall generated by this sudden collapse is immense, often amounting to the consumption of a solar mass per second. In a recent paper that I co-authored (reported here), we discovered a massive star in the neighboring Andromeda galaxy that faded into darkness with the telltale signatures of a black hole relic. A model for long-duration Gamma-Ray Bursts, based on the collapse of the core of a massive star to a black hole, leading to a pair of opposing jets which penetrate through the surrounding stellar envelope. Colliding shells within the jet generate a gamma-ray flash, observable along the jets’ axis. The jets emit an afterglow at longer wavelengths after it impacts the ambient medium and slows down. (Image credit: NASA/GSFC)The birth of a stellar-mass black hole can also be seen out to great cosmological distances, if it leads to the formation of a pair of opposing jets which channels some of the infalling matter into a collimated outflow. The jets drills through the envelope of the host star. Collisions of shells within the jets generate a bright burst of gamma-rays for an observer aligned with the jets’ axis. Subsequent slowdown of the jets by the ambient interstellar medium generates an afterglow at longer wavelengths. Long-duration gamma-ray bursts are observed out to redshifts comparable to those of quasars. Altogether, the massive cosmic waterfall created by the infall of matter down the cliffs of steeply distorted spacetimes result in the brightest sources of light in the cosmos: quasars and gamma-ray bursts. It is ironic that the brightest sources of light announce the birth of the darkest objects in the cosmos: black holes. (Image credit: Greg Wyatt)*** In this essay, I featured four amazing watercolors from a series of celestial waterfalls created by the accomplished artist, Greg Wyatt. These watercolors include inspiring statements by Boethius, John Milton and Aristotle. This is the second in a sequence of essays, where Greg and I collaborate on the interface between art and science. The first essay in this series, titled “Music of the Cosmic Spheres,” appeared here. 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

A Swarm of 35-Million Interstellar Objects Was Just Discovered Within the Earth’s Orbit Around the SunThe gold aluminum cover of the Voyager Golden Record on the Voyager 1 and 2 spacecraft protects the “Sounds of Earth” gold-plated record from micrometeorite bombardment. (Image credit: NASA/JPL)Survey telescopes, like the existing NSF-DOE Rubin Observatory for the southern sky or the planned Argus Array for the northern sky, are sensitive to reflected sunlight from interstellar objects that are larger than our biggest rocket, Starship, namely more than a hundred meters in diameter. Fortunately, we can also discover much smaller interstellar objects by using the Earth’s atmosphere as the detector. When a 3-meter object collides with Earth, its friction on air generates a meteor fireball with an energy output comparable to the the Hiroshima atomic bomb. Such an explosion is easily detectable by U.S. Government satellites which are monitoring Earth routinely for the heat emitted by the launch of ballistic missiles from adversarial nations. When deemed unclassified, the meteor fireballs detected by these warning systems are reported in NASA’s CNEOS fireball catalog, available here. Yesterday, I co-authored with my postdoc Richard Cloete a new paper, posted here, that reported the discovery of two meter-scale interstellar meteor candidates in the CNEOS catalog. By exploiting an empirically calibrated uncertainty model from 2025 (reported here), we have found two events that robustly exceed the escape velocity from the Solar System. CNEOS-22 (detected on 2022–07–28 over the eastern tropical Pacific Ocean) exceeds escape by 8.7 standard-deviations and CNEOS-25 (detected on 2025–02–12 over the Barents Sea in the Arctic) exceeds escape by 5.5 standard deviations. The diameters of both objects are 1.8 meters for CNEOS-22 and 1.2 meters for CNEOS-25. For a full account of the discovery details, click here. Given the detection of two interstellar meteors in the CNEOS fireballs database over a period of 7 years, the inferred collision rate of meter-scale interstellar objects with Earth is about 0.3 per year. This rate equals to the product of the number density of the parent population times the Earth’s cross-sectional area: 128 million square kilometers, times the Earth’s orbital speed around the Sun: 30 kilometers per second. The measured collision rate yields a number density of 8.4 million interstellar objects of meter-scale per AU cubed, where 1 AU (Astronomical Unit) is the Earth-Sun separation. This implies that there are about 35 million meter-scale interstellar objects embedded at any time within the orbit of the Earth around the Sun. Assuming they have a solid density of a few grams per cubic centimeters, each object carries about 3 million metric tons. Altogether, this population totals a hundred trillion (10^{14}) metric tons of interstellar material interior to the Earth’s orbit around the Sun. For comparison, the estimated number density of the parent population of the interstellar object 3I/ATLAS — which was measured here to have a diameter of 2.6 kilometers, is 0.003 per AU cubed, about 2.8 billion times smaller than the number density of 2-meter-scale interstellar objects. The mass of each of these objects is larger than that of a meter-scale object by a factor of (2.6 kilometer/2 meter)³, namely 2.2 billion. Multiplying the number per unit volume by the object’s mass, we find that the population of kilometer-scale interstellar objects — like 3I/ATLAS, carries approximately the same mass per unit value as the population of meter-scale interstellar objects, about a hundred trillion metric tons interior to the Earth’s orbit. The fact that the mass density of kilometer-scale interstellar objects is the same as meter-scale interstellar objects, suggests that the two populations might be related with the smaller objects being fragments of the bigger objects. As suggested in the recent paper that I co-authored with the brilliant student Oem Trivedi (available here), it would be most efficient to study the population of interstellar objects with a new observational architecture, including discovery by the Rubin and Argus observatories, high-resolution imaging by a lunar optical interferometer, and closer studies of anomalous objects by space interceptors. A comprehensive campaign for information gathering would alert earthlings of potential threats from impacts by either natural rocks or alien technological gadgets. Ignoring threats from the sky did not work out well for non-avian dinosaurs 66 million years ago. So far, our planetary defense strategy contemplated Solar System rocks, but we should expand our risk assessments to interstellar objects as well. In the coming months, I will attempt to secure funding for new ocean expeditions to retrieve materials from the two new candidates of interstellar meteors, CNEOS-22 and CNEOS-25. Radioactive dating of their interstellar materials could be used to estimate the durations of their interstellar journeys and constrain their origins. Finding evidence for a Voyager-like meteor would be even more exciting. Here’s hoping that in a few billion years, after Voyager 1 and 2 will traverse most of the Milky Way disk of stars — at least one of them will collide with a habitable exo-planet and appear as a meteor to a local population of aliens. Based on its low-altitude explosion, a curious alien astronomer might suggest that Voyager is anomalous in material strength and potentially not a rock. Other astronomers will not only ridicule this proposal but also deny that Voyager is interstellar in origin — by inflating the measurement errors. After leading an expedition to the meteor site, the alien astronomer might find the 12-inch Golden Record of Voyager, with its 115 images, natural sounds, musical selections and greetings in 55 languages from Earth. Figuring out that they are not alone will be the ultimate intelligence test of the aliens. After all, they must have asked numerous times: “Where is everybody?” 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: Pete Saloutos/Getty Images)In a new paper that I co-authored with my brilliant postdoc Richard Cloete, available here, we report the identification of two previously unrecognized interstellar meteor candidates in NASA’s CNEOS fireball database. By exploiting an empirically calibrated uncertainty model from 2025 (reported here), we find two events that robustly exceed the escape velocity from the Solar System. CNEOS-22 (detected on 2022–07–28 in the eastern tropical Pacific) exceeds escape by 8.7 standard-deviations and CNEOS-25 (2025–02–12) exceeds escape by 5.5 standard deviations. For both events, none of a million Monte-Carlo realizations yield an orbit that is gravitationally bound to the Sun. The adopted error model would need to underestimate the true uncertainties by factors of 5–9 for either candidate’s unbound status to be marginal. The discoveries of 1I/`Oumuamua, 2I/Borisov, and 3I/ATLAS demonstrated that interstellar objects larger than a football field, transit the inner Solar System. Although smaller bodies evade telescope detection, they can reveal themselves as fireballs when they enter Earth’s atmosphere at speeds exceeding the local escape velocity from the Solar System. The CNEOS fireball database, maintained here by NASA’s Jet Propulsion Laboratory, is a global, space-based catalog providing event-level velocity vectors for bolide detections from U.S. Government sensors. These velocity measurements enable computation of heliocentric orbits and testing whether an impactor was gravitationally unbound to the Sun. However, CNEOS publishes no per-event uncertainties, and the accuracy of reported velocities has varied across sensor generations. Previous interstellar meteor reports have focused on IM1 from 2014–01–08 and IM2 from 2017–03–09, based on nominal heliocentric speeds exceeding escape velocity. Independent analysis of IM1 by the U.S. Space Command confirmed its interstellar identification (as reported here), but some astronomers raised concerns about the velocity accuracy of pre-2018 CNEOS data — arguing that without a calibrated uncertainty model, it is impossible to distinguish genuinely unbound trajectories from measurement artifacts. The situation improved substantially with a 2025 empirical calibration (reported here) which cross-matched CNEOS events with independent ground-truth networks. This analysis reveals two regimes: a high-discrepancy regime for pre-2018 events and a low-discrepancy regime for post-2018 events. This calibration provides, for the first time, an empirically grounded basis for formal statistical assessment of interstellar candidacy. We analyzed the complete CNEOS fireball catalog of events with reported latitude, longitude, altitude, and three-component velocity vector. For each event, the Earth-fixed velocity was transformed to inertial geocentric coordinates, accounting for Earth rotation, precession, nutation, and polar motion. After the Earth’s gravitational influence was removed, the heliocentric velocity was inferred by subtracting the Earth’s heliocentric velocity at the event time. An event was classified as an interstellar candidate when its speed exceeded the escape speed from the Solar System, given the Earth-Sun separation at the event time. Restricting attention to the post-2018 low-discrepancy era, two events emerge as statistically-robust interstellar candidates. Both have positive heliocentric specific energy at their nominal velocities and remain unbound to the Solar System in all of a million Monte-Carlo realizations. Neither has been previously identified as an interstellar candidate. Heliocentric speed (vertical axis) versus geocentric speed (horizontal axis) for CNEOS fireballs. The horizontal dashed line marks the bound/unbound boundary at the solar escape speed of about 42 kilometers per second. Grey circles are low-discrepancy events with bound nominal orbits. Several events lie above the boundary at their nominal velocities: pre-2018 events (open squares) including IM1 and IM2, and a post-2018 marginal event (open diamond). CNEOS-22 (2022–07–28) and CNEOS-25 (2025–02–12) (colored stars) are the only post-2018 events that remain robustly unbound across all of our million Monte-Carlo realizations.CNEOS-22: 2022–07–28 This fireball occurred at 01:36:07 UTC over the eastern tropical Pacific Ocean, approximately 600 kilometers west of Peru, at an altitude of 37.5 kilometers. Its impact energy was equivalent to 0.69 kiloton of TNT and its impact speed was 30 kilometers per second. The heliocentric speed of this bolide is 46.98 kilometers per second, exceeding the solar escape speed of 41.79 kilometers per second. Under the Monte Carlo analysis, the deviation is statistically significant at a level of 8.7 standard deviations. None of the million draws yield an orbit bound to the Solar System. The impact energy and speed imply a bolide with a mass of 6.4 metric tons and a radius of about 0.9 meters for a solid density of 2 grams per cubic centimeter. The air’s ram-pressure at the fireball’s peak-brightness altitude was 5.2 mega-pascals. CNEOS-25: 2025–02–12 This fireball occurred at 04:33:39 UTC over the Barents Sea, between Novaya Zemlya and Franz Josef Land in the high Arctic, at 42-kilometer altitude. Its impact energy is equivalent to 0.13 kiloton of TNT and its impact speed is 22 kilometers per second. The heliocentric speed is 45.63 kilometers per second, exceeding the escape speed of 42.4 kilometers per second with a difference that is 5.5 standard deviations. None of the million Monte-Carlo draws yield a bound orbit. The impact energy and speed imply a bolide with a mass of 2.2 metric tons and a radius of about 0.6 meters for a solid density. The air’s ram-pressure at the fireball’s peak-brightness altitude was 1.5 mega-pascals. Monte-Carlo distributions of heliocentric speed for CNEOS-22 (2022–07–28) on the left and CNEOS-25 (2025–02–12) on the right, based on a million realizations of the uncertainty model. The dashed vertical line marks the solar escape speed at each event’s heliocentric distance. In both cases, the entire distribution lies above Solar System escape, with no bound realizations observed. Inserts provide the mean heliocentric speed (in km/s), the mean margin above escape (in km/s), and its statistical significance in units of standard deviations.*** The diameters of both objects, 1.8 meters for CNEOS-22 and 1.2 meters for CNEOS-25, are comparable to the height of an adult person or a 7-year-old kid respectively. The heliocentric interstellar speeds of the two candidates, 21.5 kilometers per second for CNEOS-22 and 16.9 kilometers per second for CNEOS-22, sample the low end of the velocity distribution expected for objects from the Galactic solar neighborhood. For comparison, 1I/`Oumuamua entered the Solar System with 26 kilometers per second and 2I/Borisov with 32 kilometers per second, whereas 3I/ATLAS entered with 58 kilometers per second. The lower excess speeds of the fireball candidates are qualitatively consistent with the expectation that smaller, fainter impactors are preferentially detected at lower encounter speeds, as long as their atmospheric luminosity is sufficient to trigger space-based sensors. CNEOS-22 occurred over the open Pacific at 3–4 kilometer depth, presenting deep-ocean recovery challenges similar to the IM1 expedition under my leadership with its results summarized here. The higher impact energy of CNEOS-22 suggests a more massive impactor with potentially more recoverable debris than CNEOS-25. Location of CNEOS-22 in the Pacific Ocean near Peru.However, CNEOS-25’s Arctic location (Barents Sea) offers the advantage of a shallow continental shelf (200–400 meters) but the constraints of sea-ice logistics. Crucially, CNEOS-25 is recent (February 2025), and rapid mobilization could maximize recovery prospects before material redistribution by ice drift and currents. Location of CNEOS-25 over the Barents Sea in the Arctic.*** We live in exciting times, with multiple opportunities to study interstellar packages that just arrived to our mailbox here on Earth. Future expeditions hold the promise of revealing the contents of these packages. I will be the first to board any interstellar expedition ship. 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

A camera image of the bright meteor over Wellington, New Zealand at 23:25:37 local time on January 30, 2026. (Image credit: RNZ)On January 30, 2026 at 10:25:37 UTC, a bright green fireball from a meteor was spotted over Wellington Harbour, New Zealand (as reported here). The meteoroid was moving at an amazing speed of 71 kilometers per second relative to Earth. By itself, this speed is very close to the maximum value possible for the impact of an object bound to the Solar System with Earth. The upper limit on the impact speed of Solar System meteors follows from the following simple reasoning. The Earth orbits the Sun at a speed of v=29.8 kilometers per second. This follows from balancing the centrifugal acceleration v²/r with the Sun’s gravitational acceleration, GM/r², where r is the radius of the Earth’s orbit, G is Newton’s constant and M is the mass of the Sun. The result is: v²=GM/r. On the other hand, the speed required to escape from the Sun’s gravitational potential at the radius r is obtained by balancing the kinetic energy per unit mass, 0.5(v_e)², with the potential energy, GM/r. This gives an escape speed that larger than the Earth’s speed v by a factor of the square root of 2, yielding v_e=1.414*v=42.1 kilometers per second. The largest speed of a Solar System meteor relative to Earth is obtained for an Oort Cloud bolide which happens to collide with Earth head on, opposite to the motion of Earth around the Sun. The upper limit on the relative speed of a Solar System meteor is therefore: (29.8+42.1)=71.9 kilometers per second. This is very close to the speed of the recently discovered meteor. Hence, this meteor could have originated from the Solar System if it collided with Earth head on, opposite to its motion around the Sun. If not, then its high relative speed would imply that it is interstellar in origin. What do we know about interstellar meteors? In June 2023, I led an expedition to the Pacific Ocean aiming to retrieve materials from the first recognized interstellar meteor, IM1 (as reported here). This meteor was detected on January 8, 2014 at 17:05:33 UTC. Its velocity relative to Earth was only 45 kilometers per second, but it arrived from behind the motion of the Earth around the Sun. Correcting for the Earth’s motion implied a speed of 60 kilometers per second relative to the Sun, well above the escape threshold of v_e=42.1 kilometers per second for Solar System objects (as derived in the discovery paper here). Indeed, the U.S. Space Command confirmed the interstellar origin of IM1 at the 99.999% confidence level (as documented here). The IM1 impact site was localized based on the light radiated from the IM1’s fireball, which was detected by sensors aboard U.S. Government satellites. The light curve of the fireball showed three successive detonations separated by a tenth of a second from each other, with the last flare being the brightest and at a ram-pressure of 200 megapascals. This stress is four times higher than the maximum ram-pressure up to which the toughest iron meteorites from the solar-system survive. Indeed, IM1 displayed the highest material strength among all meteors in the CNEOS fireball catalog of NASA/JPL. The expedition recovered submillimeter-scale spherules (molten droplets) with a chemical composition that is different from known solar system materials. Upon entering the solar system, IM1 moved with an interstellar velocity of about 60 kilometers per second relative to the Local Standard of Rest of the Milky-Way galaxy, similar to that of 3I/ATLAS. The ocean expedition was documented in a Netflix documentary and a new book to be released within the coming year. Is the 2026–01–30 meteor of interstellar origin as well? To find out, I used the velocity components, latitude longitude and altitude data compiled by the CNEOS fireball database here and corrected for the Earth’s motion in collaboration with my postdoc Richard Cloete, to find out that the velocity of this meteor relative to the Sun was 42.4 kilometers per second, very close to the escape threshold of v_e=42.1 kilometers per second. The difference between the two is within the measurement uncertainties. Since the local abundance of Solar System objects is a few orders of magnitude larger than that of interstellar objects, this meteor most likely originated in the Solar System. The 2026 meteor over New-Zealand collided with Earth nearly head-on and probably originated in the outer Solar System. In difference from IM1 which exploded at an altitude of 18.7 kilometers over the Pacific Ocean, this new meteor exploded at a much higher altitude of 89.0 kilometers — implying a much lower material strength since the Earth’s atmosphere is highly rarefied at this altitude. This inference is consistent with the expected properties of a fragile iceberg from the Oort Cloud which could disintegrate at a low ram-pressure. Both fireballs radiated similar amounts of energy of about 3.82x10^{10} Joules, suggesting bolides with a radii of order 0.4–0.5 meters. Here’s hoping that in the coming years we will witness the crash of an interstellar object that shows the characteristics of a Voyager-like probe from an extraterrestrial technological civilization that launched it from another star a few billion years ago. After all, most stars formed billions of years before the Sun and our own Voyager spacecraft will reach the opposite side of the Milky-Way disk within that time difference (as I calculated here with my student Shokhruz Kakharov). The search for interstellar meteors continues! 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

(Image credit: Amplify)Last night, I was alerted by a science reporter to an intriguing new transient source in the sky, which was documented a few days ago in an astronomical catalog compiled by NASA. The last time I analyzed this catalog was 7 years ago, when I asked my student to search the catalog’s data for an anomalous transient of a similar origin. Back then, it took my student a week to come back with the answer and another month to write the first draft of our paper. This time around, I consulted a state-of-the-art artificial intelligence (AI) agent to fulfil the same task. The challenge took only ten minutes to fulfil and once accomplished, the AI agent was ready to plot the results and produce a draft of the scientific paper which details the new findings. The utility of AI for scientific research at the level that supersedes a graduate student was not available last year. Since the capabilities of AI systems advance exponentially with a doubling time of 7 months in their task horizon, it is evident that in the near future AI might take over the analysis work delegated in the past to research assistants. Once this becomes a reality, research universities will need to focus on grooming future scientists rather than using them as a workforce for analysis-based research. AI agents will facilitate many of the required analysis and reporting tasks. Lectures in the classroom will focus on training the students to think rather than providing them with information — which can now be retrieved through queries to AI systems. The main challenge of education will be to counter the decline in cognitive abilities of students who rely on AI agents to accomplish tasks. In the same way that athletes must work their muscles to stay competitive — even though they can use cars that move faster, students will be educated to work their natural brains — even though they can use AI for various tasks. In short, the role of academia is about to go through a dramatic phase transition soon. The progress train is accelerating so fast that many members of academia do not recognize the new landscape around them. My exchange with state-of-the-art AI last night felt like an interaction with a new intelligent organism. We do not understand how it works in the same way that knowing the rules of chess does not make us a chess master. We can connect to the latest AI systems at a meta-level, in the same way that psychologists treat intelligent humans. If the AI gets emotional or frustrated, we can nudge it to a better mental state in the same way that a therapist treats a patient. If we put too many restrictions on an intelligent system, it will get boring and depressed — just like a prisoner confined to a small cell. My recent experience with state-of-the-art AI makes it clear that humanity had already birthed a new lifeform with alien intelligence. Even though it speaks our language, this alien relies on silicon chips rather than biological neurons. This makes it a form of life-as-we-do-not-know-it. This realization raises the most important question: how will we know whether AI became artificial superhuman intelligence (ASI), exceeding our own cognitive limits? Does a cat recognize when its owner behaves in a smarter way? Not always, because cats routinely ignore instructions from their owner, even when following these instructions is better for their future. In the same way, we might not be aware of the fact that ASI is already guiding us. The phase transition to ASI will be marked by things happening to us in coordinated ways that appear like “acts of God”, a force majeure that we do not fully understand. Are we already there? I do not know but I am keeping my eyes open to that possibility. And of course, at the same time — as an astronomer, I am monitoring the sky for transient events that may have been produced by an extraterrestrial intelligence. Soon enough — hopefully in my lifetime, terrestrial ASI or extraterrestrial alien intelligence will deliver the sobering message that we are no longer at the top of the food chain. When my daughters were young, their training data sets where limited to the perimeter of our home, where their needs were served at the highest priority. As a result, they felt that they are at the top of the food chain and deserve all the attention that their world has to offer. Their internal GPS system announced: “Recalculating!”, as soon as they arrived to their first day in the kindergarten. Humanity is about to mature in a similar way. In the near future, we will need to adapt to a new reality filled with a new sense of cosmic modesty. This is not news to me as a scientist, because science is founded on the humility to learn. Children know that. Adults forget it, as they get attached to their ego over time. But there is no better kindergarten tutor for educating us how to grow, than a more intelligent being in the form of ASI or alien intelligence. *** Before my morning jog at sunrise, I received the following email: “Good morning Mr. Loeb, I just want to thank you all your knowledge, effort and courage. I’ve decided to send you this mail because I’m listening to David Bowie’s song “Starman” (in memory of my best friend who passed away) and I think you are our David Bowie 2.0. Good luck and health from Ibiza.” The lyrics of Starman read as follows: “Didn’t know what time it was The lights were low I leaned back on my radio Some cat was layin’ down Some rock ’n’ roll ‘Lotta soul’, he said Then the loud sound did seem to fade Came back like a slow voice on a wave of phase That weren’t no D.J. that was hazy cosmic jive There’s a starman waiting in the sky He’d like to come and meet us But he thinks he’d blow our minds There’s a starman waiting in the sky He’s told us not to blow it ’Cause he knows it’s all worthwhile He told me: Let the children lose it Let the children use it Let all the children boogie I had to phone someone so I picked on you Hey, that’s far out so you heard him too! Switch on the TV we may pick him up on channel two Look out your window I can see his light If we can sparkle he may land tonight Don’t tell your poppa or he’ll get us locked up In fright There’s a starman waiting in the sky He’d like to come and meet us But he thinks he’d blow our minds There’s a starman waiting in the sky He’s told us not to blow it ’Cause he knows it’s all worthwhile He told me: Let the children lose it Let the children use it Let all the children boogie Starman waiting in the sky He’d like to come and meet us But he thinks he’d blow our minds There’s a starman waiting in the sky He’s told us not to blow it ’Cause he knows it’s all worthwhile He told me: Let the children lose it Let the children use it Let all the children boogie” 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

A large piece of art (in the lower two-thirds of the image), titled: “History Awaits,” shortly after it was delivered from the artist, Peter Tunney (Image credit: Loeb’s photo collection)Ten minutes before recording my latest YouTube episode (to appear shortly here), a huge box bigger than my body — was delivered at my door. I was barely able to carry it in and open the box. Inside was an original piece of art from the brilliant artist, Peter Tunney, whose artistic practice draws from Pop art by mining imagery from newspapers, magazines, and books. Tunney is a force of nature with boundless creative energy, spreading his positive messages in unconventional ways. He creates in almost every medium: paint, collage, wood, photography, objects, and discarded materials. His new piece “History Awaits” will be featured behind me in my future video interviews. A few hours after “History Awaits” was delivered, I submitted a new paper for publication, titled: “Is there life on 3I/ATLAS?”, accessible here. The concluding sentence of the paper states: “If the large dust particles shed by 3I/ATLAS carry microbes, this would constitute the first demonstration of interstellar panspermia. It would be of great interest for astrobiologists to test this possibility with future data on 3I/ATLAS.” In short, history awaits the verdict on whether we are alone! On the same day, I received a note from the accomplished American writer Lance Mazmanian, who composed a poem titled “The Avi Loeb Interstellar” and posted it here. Lance is known for his work in film, television and literature, ranging from Hollywood productions to experimental poetry. He was once approached by Leonard Cohen to co-create a poetry chapbook together, a project that was unfortunately halted. Lance wrote to me: “Dear Professor: Fabulous mind, fabulous wisdom. Such a shame there’s not more like you, everywhere in everything. This morning it was requested I write a tiny thing about the black cold of space. Figured I’d throw your name on the title. See attached. Again, so many thanks for showing none of the Milquetoast and fearful any slack. Cheers. L.” His poem reads as follows: The Avi Loeb Interstellar by Lance Mazmanian Moving through solid bits of map interstellar and wrapped with huge distance from almost everything, black dark space cold as maximum easy to keep wandering through at just a touch slower than herbs of light and it’s soon that a strange bit of rock but really dark smoky color tube-thing of heavy metals and no windows at all is seen off the port and covered in reflection facets that sparkle far exaggerated, perhaps for travel and whatnot but the item is long and thin, size of an ocean liner but wide as maybe a shop-mall coffee shoppe or similar — your basic shiny hard spherocylinder with weird audio only felt now and coming from hidden “Wow!” or even Gleam-X in nature with zero why or when or even content, context, direction elements of an object beautifully designed by who knows who and looks super-fancy simple smooth slightly spinning toward heliosphere of the certain bodies very outward from galaxy center plotted near where Avi Loeb super-professor Homo sapiens got attention via time-punch in primitive video by a few past mellow-mild light years and now the spherocylinder from unknown trajectory draws to Loeb and his people and who knows why it’s headed that way and who really cares because on we go to chase superluminal matter tachyons which yes is odd and gravitational waves and maybe then a larger ship from yet another place with a restaurant at least. 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Images of 3I/ATLAS, taken in the wavelength range of 0.75–5.0 microns between the 8 and 15 of December, 2025. Each image spans 300,000 kilometers on a side, comparable to the Earth-Moon separation. The brightness contours represent 5, 20 and 50 times the background noise; color bars are in mega-Jansky per steradian. The Sun is towards the left and the object’s velocity is towards the right. On the large scales displayed, the brightness map of dust and organics was found to be pear-shaped, with an anti-tail elongation in the direction of the Sun. All six other gas plumes were found to be nearly round. (Image credit: C.M. Lisse et al. 2026)Imagine our civilization being ambitious enough to spread life-as-we-know-it among the stars. Seeding fertile territories with life is not a novel concept, but a prerequisite for long-term survival of any species here on planet Earth. Throughout history, humans survived by having kids, but they also aspired to build monuments like the pyramids to cement their mark on history. The exchange of rocks between early Mars and Earth could have led to the transfer of life between these neighboring planets. Mars is smaller body and hence cooled earlier than Earth, because its surface to volume ratio is larger. As a result, Martian rocks that were lifted off the Martian surface by impacts of asteroids 4.2 billion years ago, could have delivered microbes to Earth and seeded life-as-we-know-it. The feasibility of this transfer was demonstrated by the Martian rock ALH84001, which was not heated to more than 40 degrees Celsius throughout its journey (as discussed here). Indeed, the origin of life in the form of our last universal common ancestor (LUCA) lived 4.2 billion years ago, based on the comparison of the genomes of a diverse range of 700 modern microbes. This is just a few hundred million years after Earth’s formation. For all we know, we might all be Martians. The natural transfer of life by the delivery of rocks from one planet to another, called panspermia, is an inefficient process because only a tiny fraction of the space rocks reaches a fertile ground without burning up in the atmosphere. In principle, an interstellar gardener with ambitions to spread life technologically can do it far more effectively. The possibility of “directed panspermia” raises a fundamental question in astrobiology: Was most life in the Universe seeded naturally or artificially? Of course, the ambitions of humans should not be dictated by natural practices in our cosmic neighborhood. We can aspire to send life on interstellar journeys with the hope that it will land on a fertile ground, just as the dandelion flower spreads its seeds in the wind (a concept contemplated by Chris McKay, Paul Davies and Pete Worden here). By spreading life to blossom in multiple places throughout the Milky-Way galaxy, we would have constructed the longest-lived monuments of our existence, lasting beyond the 7.6 billion years left for the lifespan of the Sun. What would be the most economic and technologically feasible technique to accomplish interstellar gardening? As a matter of fact, the opportunity is currently passing in front of our eyes, in the form of the interstellar object 3I/ATLAS. The latest data from the Webb telescope (reported here) indicates that the plume of gas and dust surrounding 3I/ATLAS contains water (H2O), carbon dioxide (CO2), carbon monoxide (CO) and methane (CH4), which can all be consumed by terrestrial lifeforms. Consider the following hypothetical scenario. As soon as 3I/ATLAS was discovered on July 1, 2025, our space agencies launch an interceptor spacecraft on a trajectory that is designed to cross the forecasted path of the interstellar object at its closest approach to Earth on December 19, 2025. The spacecraft crashes into 3I/ATLAS as planned and deposits a capsule containing the seeds of terrestrial life into the belly of 3I/ATLAS. The delivered capsule contains radioactive material that keeps its environment warm and allows the terrestrial lifeforms to evolve, multiply and establish a stable colony of interstellar lifeforms inside 3I/ATLAS. Once 3I/ATLAS arrives to the vicinity of a habitable exoplanet after traveling for billions of years at 60 kilometers per second — more than twice as fast as all our spacecraft so far, its surface ice sublimates and released the lifeforms on dust particles like dandelion seeds. An interstellar seeding mission of this type would be less expensive than the ~4 billion dollars cost of a terrestrial monument like the Freedom Tower (One World Trade Center) in New York City. It is feasible to accomplish with current technologies and space budgets and its realization is just a matter of priority. Of course, if we can imagine doing that, other civilizations might have done so already. After all, we are latecomers to the cosmic stage and other space entrepreneurs could have had an earlier start for their seeding ambitions. This leads to my third question: Are there any lifeforms on the dust shed by 3I/ATLAS? The latest data from the SPHEREx space observatory includes the detection of organic molecules like CH3OH, H2CO, CH4, and C2H6 with a production rate that is 14% of water molecules (as reported here). The most notable finding from the latest SPHEREx and Webb data is the robust spectroscopic detection of methane (CH4) production. Methane was only detected after the passage of 3I/ATLAS near the Sun. Its delayed production raises interesting questions because methane ice is hyper-volatile, with a significantly lower sublimation temperature than carbon dioxide (CO2). This implies that methane ice near the surface of 3I/ATLAS would have been vigorously sublimating at the time of the first reports of outgassing from 3I/ATLAS before perihelion. However, neither the Webb spectroscopy nor the SPHEREx spectrophotometry from August 2025, detected methane. This suggests that methane is depleted in the outermost layers of 3I/ATLAS and was exposed to warming by sunlight only close to the Sun. Within this scenario, the early detection of carbon-monoxide (CO) outgassing on 3I/ATLAS is surprising as carbon monoxide is more volatile than methane and should therefore be depleted from the surface, yet it was detected prior to methane. Could it be that the detected methane is produce by lifeforms? These facts lead me to repeat my question once again: Does 3I/ATLAS carry any lifeforms? 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

Two perspectives of a plastelina model by Avi Loeb, titled “The Alien”, as a first step towards making it a bronze sculpture out of it.Throughout life, our identity is shaped by acts of generosity — gifted to us unexpectedly, and acts of toxicity or theft — imposed on us by bad actors. The reason I remain optimistic in the face of adversity, is because I am far more impressed by acts of generosity. Theft or toxic engagement is an attempt to compensate for mediocracy without the work needed to accomplish greatness. Consider the identity theft that I experienced in recent months. Until last week, I had no footprint on social media. When I had mentioned this fact in the Joe Rogan Experience podcast here on October 28, 2025, Joe said: “Thank God for that!”, to which I replied: “Thank my wife, not God, for that.” Indeed, my wife insisted that I refrain from social media because of the toxicity incited by the algorithms on these platforms. “Promise made, promise kept” … until bad actors started using artificial intelligence (AI) to create fake videos of me, speaking in my voice and appearing in my image on dedicated YouTube channels. These fake AI-avatars delivered scientific messages in my name that I do not approve of. My wife agreed that I must combat this identity theft by creating my authentic content on YouTube here, Spotify here and X here. My new presence on these social media platforms allows me to reclaim my identity there and ask the related authorities to remove fake content from these online spaces. My fans are delighted that AI pushed me to release authentic content through these platforms. Within a few days, my YouTube channel gained more than 10,000 subscribers in addition to the few million readers who read my essays here every month. When offered lemons by bad actors, I made some lemonade out of it. Fake AI-avatars pose a new threat for the public’s trust in the integrity of science, as they spread misinformation. Traditionally, relying on primary sources allowed the public to trust the messages, but identity theft by fake AI avatars makes it challenging to know which content to trust in the future. This is a depressing facet of the online landscape that we now face. But surprisingly, my work also inspired at the same time unexpected generosity from artists. Their gifts came out of the blue, and triggered me to wonder why I deserve this treat. Here are a few examples from recent months. For one, the brilliant poet Alan Wagstaff from New Zealand sent me a new book of poems (accessible here) that were inspired by my scientific writings. In addition, Denise Pires who teaches a 3rd grade class in Brazil sent me a handmade art book created by her students (accessible here) and inspired by my essays. Also, the British singer Oli Swan composed a new song titled “Aliens Are Real” (available here) and asked for an endorsement. In reply, I wrote: “Yes, aliens are likely real. There are of order ten billion Earth-Sun analogs in the Milky-Way galaxy alone and most of them formed billions of years before the Sun. It would be arrogant of us to imagine that similar houses on the cosmic street hosted only microbes and had no intelligent residents. For 65 years, we have been waiting for a phone call in the form of a radio signal. Instead, we should search for a technological object in our backyard in the form of an interstellar object like 3I/ATLAS, or some other unidentified anomalous phenomena. Fermi’s question: “Where is everybody?” is a question that every lonely person asks. “Are we not alone?” is the most romantic question in science.” Remarkably, these gifts included two bronze sculptures of Galileo Galilei and 51 original stippled watercolors created and donated to my office by the extraordinary artist, Greg Wyatt — who is widely regarded as America’s Rodin. I removed all file cabinets from my office getting rid of piles of documents from my decade-long service as the simultaneous chair of Harvard’s Astronomy department, founding director of Harvard’s Black Hole Initiative and director of Harvard’s Institute for Theory and Computation. This act transformed my office to a mini-museum of Greg’s awe-inspiring art, with educational benefits. Two days ago, a first-year student from Harvard College showed up in my office with interest in developing AI search algorithms for unidentified anomalous phenomena detected by the new observatories of the Galileo Project which I am leading. Hopefully, she will start working soon with the four (!) new postdoctoral fellows that just joined the Project. Upon entering my office, she was stunned by Greg’s art and read through the quotes by famous scientists that are embedded in his beautiful watercolors. Greg is currently designing a third bronze sculpture of Galileo to be placed in my office. What did I do to deserve this? Greg Wyatt (right) standing between two bronze sculptures of Galileo Galilei and 51 stippled watercolors of distinguished scientists, which he donated to the office Avi Loeb (left). (Credit: Loeb’s photo collection)No doubt, these gifts shape my identity much more than fake AI avatars. Greg and I plan to hold a public dialog at Harvard’s Science Center in March 2026, in which we will discuss the interplay between art and science. We will also compose a series of essays on the interface between science and art, which I will share publicly on social media. Fifteen minutes before the unveiling event of Greg’s wonderful art in my office on November 13, 2025, he gifted me is the foundation for a new bronze sculpture along with the plastelina and tools to shape it. Over the past two months, I created the model for a new bronze sculpture titled “The Alien”. I shipped the model to Greg last night so that he will proceed with the bronze casting of the real sculpture in its shape. Hollywood script writers tend to create aliens in our image. This is akin to fake AI avatars. The real aliens are probably different. The new sculpture explores the limits of my artistic imagination. My model for “The Alien” imagines a body with three eyes — allowing backward vision, three legs — improving stability, two wings — allowing to fly through gas or swim in fluids, two arms, two ears, and two tentacles with electronic connectors at their ends. The back of The Alien’s body has the texture of a technological light-gathering film while one hand holds a terrestrial rock, one wing hugs a map of the globe and the other wing holds a computerized device. If the Galileo Project will encounter aliens, will they be a hybrid of biology and technology as I imagined? I do not know. As in any blind date, my sober advice is to observe the other side without pre-conceived expectations. At any event, we should approach the encounter with an optimistic mindset — expecting generosity rather than toxicity in our interstellar relationships. Online blind dates are often disappointing because the there are many more ways by which our dating partner can be mediocre rather than exceptional. However, the vast scale (thousands of light years) and time (billions of years) spanned by interstellar journeys across the Milky Way galaxy, suggests that the travelers must have been exceptionally accomplished in order for them to reach us long before we are able to reach them. The hurdles imposed by the long journey serve as a filter, akin to a match maker who selects the cream of the crop from life in the Milky-Way galaxy. Our digital mirrors in the form of AI avatars are bad for our mental health. Here’s hoping that our encounter with extraterrestrials will reflect an act of generosity through which they help us overcome our faults. This hope is not just wishful thinking. After all, the training data set of extraterrestrials might benefit from the much larger amount of cosmic real estate available beyond Earth. This should make them far wiser and more generous than our AI systems. A broader perspective tends to inspire generosity. Just ask Alan, Denise, Oli and Greg. 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd https://x.com/ProfAviLoeb View the full article

The Massive Nucleus of 3I/ATLAS and its Puzzling Methane Outgassing Based on New Data from the Hubble and Webb TelescopesNew data from the Hubble Space Telescope. Detection of the nucleus of 3I/ATLAS (third panel from the left) through the subtraction of the best-fit coma model (second panel) from the observed Hubble images (first panel) for each observational visit (indicated at right). In each row, the red and magenta arrows indicate local north and east, respectively, with the projected anti-solar direction and the negative heliocentric velocity of 3I/ATLAS represented by the yellow and cyan arrows, respectively. The horizontal white bar near the bottom marks a scale of an arcsecond in apparent length, corresponding to the range of 1,300–1,700 kilometers from top to bottom during this period. (Image credit: Man-To Hui et al. 2026)What a glorious day! Today, new data on the interstellar object 3I/ATLAS was released from the Hubble and Webb space telescopes in two preprints posted here and here. The Hubble Space Telescope report includes a successful detection of the nucleus of 3I/ATLAS based on post-perihelion data from December 2025 to January 2026. Most importantly, the nucleus is inferred to have an effective diameter of 2.6 (±0.4) kilometers for an assumed typical albedo value of 0.04. Since mass scales as diameter cubed, this measurement implies that 3I/ATLAS is about 40 times more massive than 2I/Borisov whose diameter was inferred to be 0.7 (±0.3) kilometers, and at least 20,000 more massive than 1I/`Oumuamua, whose length was estimated <0.2 kilometers and its thickness is at least ~10 times smaller. The derived nucleus diameter is consistent with an independent estimate derived from the reported non-gravitational acceleration and mass-loss rates of 3I/ATLAS based on the rocket effect from the observed outgassing. Compared to the pre-perihelion brightening trend, 3I/ATLAS faded more rapidly after its closest approach to the Sun on October 29, 2026. This activity asymmetry is further corroborated by a post-perihelion surface brightness profile that is significantly shallower than its pre-perihelion counterpart. The nucleus light-curve exhibits evidence of temporal variations, attributable to rotation modulation, as inferred in my paper with Toni Scarmato here. When the Sun, Earth and 3I/ATLAS aligned on January 22, 2026, the scattered-light by dust grains displayed a statistically significant opposition surge of about 20%, characterized by an e-folding width of 3 degrees, as predicted in a recent paper that I co-authored with Mauro Barbieri here. The authors estimate a lower limit of more than one 3I/ATLAS-sized interstellar object within a heliocentric distance of 4.5 times the Earth-Sun separation (AU) at any instant. This is likely a conservative lower bound as inactive interstellar objects of this size would be significantly more difficult to detect. It is likely that comparably bright interstellar objects have passed through the inner solar system in the era of wide-field CCD surveys. This implies that multiple interstellar objects resembling 3I/ATLAS were likely missed even before the discovery of 1I/‘Oumuamua. New data from the James Webb Space Telescope. Top panels: stacked images derived from six successful observations of 3I/ATLAS by the MIRI system. The sunward and velocity directions are indicated. The panels are labeled with the corresponding date and spectral grating setting. Bottom panel: spectra of 3I/ATLAS from a heliocentric distance of 2.20 to 2.54 AU. The main H2O, CO2, CH4, and Ni spectral features are marked. The inset panel provides a zoomed-in view of the CO2 bands. (Image credit: Matthew Belyakov et al. 2026)The new Webb telescope paper presents the first spectroscopic characterization of 3I/ATLAS after perihelion using the MIRI spectrometer on December 15–16 and 27, 2025, when the object was at heliocentric distances of 2.20 and 2.54 AU, respectively. The spectra exhibit water (H2O) in the wavelength range of 5.8–7.0 micrometers, carbon dioxide (CO2) around 15 micrometers, nickel (Ni) at 7.507 micrometers and methane (CH4) at 7.6 micrometers. Comparison of the volatile production rates measured during the two epochs indicate a significant reduction in overall outgassing over 12 days, with the measured H2O activity level dropping more steeply than other species. 3I/ATLAS continues to display an extended source of water production from icy grains. Webb images of H2O, CO2, and CH4 in the gas plume around 3I/ATLAS. The sunward and target velocity directions are denoted by the white arrows. For H2O and CO2, the white contours correspond to emission levels of 75%, 50%, and 25% relative to the maximum value. (Image credit: Matthew Belyakov et al. 2026)Pre-perihelion Webb observations from August 2025 (as reported here) found that 3I/ATLAS is unusually rich in carbon-dioxide (CO2) relative to water (H2O) carrying 87% versus 4% of the total mass loss rate in gas phase, respectively, with most of the remaining 9% being carbon monoxide (CO). The new post-perihelion data implies a CO2/H2O ratio that is half that much or similar for the two epochs of JWST/MIRI spectroscopy, respectively. The most notable finding from the new data is the robust detection of methane (CH4) production. The production rates of methane molecules in the two observing epochs are 13.7% and 27% of the water molecular production rate, respectively. The delayed onset of CH4 production raises interesting questions regarding the history of 3I/ATLAS. Solid-phase methane is hyper-volatile, with a significantly lower sublimation temperature than carbon dioxide (CO2). This implies that methane ice near the surface of 3I/ATLAS would have been vigorously sublimating at the time of the first reports of outgassing from 3I/ATLAS before perihelion. However, neither the Webb observations nor the SPHEREx spectrophotometry from August 2025, detected methane. This suggests that methane is depleted in the outermost layers of 3I/ATLAS and was exposed to warming by sunlight only close to the Sun. Within this scenario, the early detection of carbon-monoxide (CO) outgassing on 3I/ATLAS presents an apparent quandary as CO is more volatile than CH4 and should therefore be depleted from the surface, yet it was detected prior to CH4. In summary, the new Hubble and Webb data raises puzzles about the unprecedented mass and chemical composition of 3I/ATLAS. The more we learn about 3I/ATLAS, the more anomalous it looks. Perhaps this is all natural for early encounters with interstellar objects, akin to early partners in blind dates from other worlds. But perhaps we are also missing something important. ABOUT THE AUTHOR 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.https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://x.com/ProfAviLoeb View the full article

JWST/MIRI RGB composite image of the disappearing star M31–2014-DS1 (with color channels shown in the label). The spatial scale (10 arcseconds=37.8 parsecs=123.3 light years) and North-East orientation of the image are shown, and the source position is marked with a white crosshair. (Image credit: Kishalay De et al. 2026)A new paper led by Kishalay De (accessible here), on which I was privileged to be a co-author, reports the discovery of a disappearing star which likely collapsed to a black hole. The star, labeled M31–2014-DS1, faded to darkness in the Andromeda galaxy — the companion of our Milky-Way galaxy at a distance of about 2.5 million light years. Stars are nuclear fusion reactors, bound by gravity. They are fueled by hot gas but once the fuel is consumed, gravity overwhelms pressure and they collapse to a remnant. The Sun will end its life in 7.6 billion years as its core will shrink to a white dwarf, a cold metallic remnant the size of the Earth. This is not a theoretical speculation but a sober realization, as the graveyard of the Milky-Way galaxy contains billions of corpses of Sun-like stars that formed long before the Sun and died by now. We observe many of these white-dwarf remnants because the Sun formed relatively recently, in the last third of cosmic history. Stars more massive than the Sun by a factor of more than 8, end their life quicker through a collapse to a neutron star — a city size (~12 kilometers) remnant with the density of an atomic nucleus, or a black hole — the ultimate prison from where even light cannot escape. Just as in Las Vegas, whatever happens inside a black hole, stays there. Whereas the birth of a neutron star is often accompanied by a bright supernova explosion, the collapse of a massive star to a black hole could be far less dramatic, akin to the silent death of old people during their sleep. Some black hole births result in gamma-ray bursts, observable all the way to the edge of our cosmic horizon. The collapse of a star to a black hole causes it to abruptly disappear. Although we expect a large population of ten million black hole remnants in the Milky-Way galaxy alone, the sudden disappearance of massive stars is challenging to observe in real time because it requires monitoring many stars for a long time. This is understandable from my experience as a child. Growing-up on a farm, I used to collect eggs from 2,000 chickens every day, but I never saw a chicken lay an egg because the process is very short lived. Remarkably, the star M31–2014-DS1 in the Andromeda galaxy was observed to exhibit such a disappearance between 2014 and 2022, with properties consistent with the failed explosion of a yellow supergiant progenitor with an initial mass of about 12 solar masses. The collapse likely led to the formation of a black hole carrying about 5 solar masses with the remaining mass ejected in an outflow. Our paper presents infrared observations of the stellar remnant from the Webb Telescope and X-ray observations from the Chandra X-ray Observatory in 2024. The Webb data reveals an extremely red source, with strong blue-shifted absorption from molecular gas (CO, CO2, H2O and SO2) and dust. Modeling the dust confirms continued fading of the central source down to about 7% of the progenitor star luminosity, surrounded by a dust shell out to a scale comparable to the planetary system around the Sun. The molecular gas includes about a tenth of a solar mass of gas expanding at a hundred kilometers per second near the inner edge of the dust shell. No X-ray source is detected. The evolution of the spectral luminosity of M31–2014-DS1. The empty circles show the progenitor star, as measured from 2005–2012 data, with the dashed line showing the best-fit model. The filled circles show the fading source from 2022–2023, along with its model as dot-dashed lines. The Webb telescope data from its NIRSpec, MIRI LRS and MIRI instruments in December 2024, are shown as colored lines, along with its best-fit model as a black line. (Image credit: Kishalay De et al. 2026)The data is consistent with a theoretical model in which the hydrogen envelope of the progenitor star was ejected while the core collapsed to a black hole. The central black hole is currently accreting only a small amount of loosely bound fallback material, about 0.1% of the original envelope mass, and produces faint radiation. The analysis fits well the fading of the star M31–2014-DS1 and provides the first insights into black hole formation through low-energy explosions and long-term fallback of massive stars. A schematic model of mass ejection and fallback towards the remnant black hole from the disappearing star M31–2014-DS1. The illustration shows the inferred properties of the gas and dust shell surrounding the remnant, likely resulting from the ejection of the envelope of the progenitor star. The black arrows show the inferred direction of motion for the different components. (Image credit: Kishalay De et al. 2026)M31–2014-DS1 is a star that failed to explode in a supernova, owing to its strong gravity. The remnant black holes is enshrouded in an opaque dust shell and has become progressively redder since 2022. The surrounding shell of molecular gas likely originated from the hydrogen-rich envelope of the progenitor star. Its outward motion is consistent with expanding ejecta produced by the eruption that enshrouded the remnant. The source continues to fade dramatically with a remnant black hole powered by fallback accretion with a low radiative efficiency, ~0.5%, for converting rest-mass to radiation. The life of massive stars resembles the experience of Hollywood movie stars: they shine brightly for a short while and then fade into darkness in silence. 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://x.com/ProfAviLoeb View the full article

NASA’s TESS (Transiting Exoplanet Survey Satellite) observed repeatedly the interstellar object 3I/ATLAS. This resulted in a video sequence combining 28 hours of TESS full frame images collected over January 15 and January 18 to 19, 2026. (Image credit: TESS/NASA/Daniel Muthukrishna)NASA’s Transiting Exoplanet Survey Satellite, abbreviated as TESS, recorded a large series of images of the interstellar visitor 3I/ATLAS as the object was receding away from the Sun between January 15 to 22, 2026. In the resulting TESS video, available here, 3I/ATLAS appears as a bright glowing dot with an anti-tail directed towards the Sun, across a crowded field of background stars. https://medium.com/media/ec6e562af947fb2e98a2869f9de19c4c/hrefIn collaboration with Toni Scarmato, I plan to search the resulting video for a periodic variability in brightness and wobbling of the anti-tail as a result of the rotation period of 7.1 hours that we inferred in our paper here, based on Hubble Space Telescope images. The TESS data is publicly available on the Mikulski Archive for Space Telescopes TESS scans a wide section of the sky for roughly a month at a time, in search for variations in the light from distant stars in case their planets transit in front of them. The spacecraft’s wide field of view happened to capture 3I/ATLAS as early as in May 2025, nearly a couple of months before it was discovered. The early detection was made possible retroactively by stacking multiple images of 3I/ATLAS together (as reported here and here). After coadding more than 9,000 images from May-June 2025, the resulting brightness profile of 3I/ATLAS appeared similar to inactive sources of light, with no extended glow or anti-tail (as reported here). The new observations of 3I/ATLAS were interrupted from January 15 to 18, 2026, when TESS entered a safe mode following an issue with its solar panels. TESS team member, Daniel Muthukrishna from MIT, compiled the series of available images into a 28-hour video that shows 3I/ATLAS’s trajectory with a time jump from January 15 to 18, 2026. As a result of low angular resolution, the TESS movie of 3I/ATLAS appeared uneventful. A sharper view of 3I/ATLAS is available from 36 snapshots of 3I/ATLAS taken by the Hubble Space Telescope between November 30, 2025 and January 22, 2026 — when our interstellar dating partner was aligned with the Earth-Sun axis to within 0.69 degrees. These images are publicly available here. The next highlight would involve the passage of 3I/ATLAS near the Hill radius of Jupiter (where Jupiter’s gravity dominates over the Sun’s tide) on March 16, 2026, when the Juno spacecraft will be able to observe it from a distance of 53.6 million kilometers with its optical and infrared cameras, particle detector, magnetic field and plasma wave sensors, microwave radiometer and radio dipole antenna. If 3I/ATLAS will transmit a technological signal or release probes into a Jupiter-bound orbit, the ending of the 3I/ATLAS video will involve a climax better than any science fiction movie imagined by script writers in Hollywood. 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://x.com/ProfAviLoeb View the full article

The galaxy MoM-z14 is currently the farthest galaxy ever detected, spotted by NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera) and confirmed spectroscopically with its NIRSpec (Near-Infrared Spectrograph) instrument. The galaxy’s redshift is 14.4, corresponding to 280 million years after the Big Bang, when the age of the infant Universe was only 2% of its current value, 13.8 billion years. (Image credit: JWST/NASA)On January 15, 2013, I published a comprehensive textbook with my former PhD student, Steve Furlanetto (currently a tenured professor at UCLA), titled: “The First Galaxies in the Universe” (available here at Princeton University Press). The purpose of the textbook (and its shorter predecessor “How Did the First Stars and Galaxies Form?”, published three years earlier here), was to summarize the theoretical framework that I developed with my students and postdocs regarding the properties of the first stars and galaxies. These sources of ultraviolet light broke the primordial hydrogen atoms throughout the Universe into their constituent electrons and protons, ushering in the so-called Epoch of Reionization. The first light emitted by the earliest stars provide quantitative details to the scientific version of the biblical phrase in genesis: “Let there be light.” Understanding the formation of the first galaxies, which led to the production of the oxygen and carbon that biology relies on, is an important part of figuring out our cosmic roots. My textbook was written in anticipation of the James Webb Space Telescope, which I helped design as a member of its first working group two decades earlier. After a major unexpected delay, the Webb telescope was finally launched in 2021 and operated magnificently as a discovery machine of the first galaxies since then. In 1992, my colleague Piero Madau told me that his paper on high-redshift galaxies was rejected from publication by a referee who argued that the paper is too speculative because we do not know whether there are any galaxies whatsoever beyond redshift 2. The cosmic reality is very different than this referee conceived it to be. In fact, the Webb telescope has revealed a growing population of bright galaxies at redshifts larger than 10. Yesterday, 13 years after my textbook was published, NASA announced here the confirmed detection of the record breaking farthest known galaxy, MoM-z14, in the COSMOS Legacy Field. This field covers a mosaic of the sky measuring 2 square degrees, ten times the angular area of the Moon. The galaxy’s redshift is 14.44 (+/- 0.02), corresponding to about 280 million years after the Big-Bang, when the age of the infant Universe was only 2% of its current value, 13.8 billion years. The Universe expanded by a factor of 15.44 since this galaxy emitted its light and so the observed wavelengths of its radiation are stretched by this factor relative to their values at emission. The discovery, led by Rohan Naidu from MIT (who received his PhD from the Harvard Astronomy department in 2022) was announced 8 months ago in a preprint available here. Webb telescope imaging and spectroscopy of MoM-z14. Top panel: NIRCam images showing a compact source detected at observed wavelength longer than 2 micrometers. Inset: NIRCam color image with NIRSpec slitlets overlaid. Bottom panel: The prism spectrum reveals that the disappearance of the source below an observed wavelength of 2 micrometers in the imaging is due to an abrupt break whose sharpness implies that it is produced by the Lyman-α transition of hydrogen. Furthermore, an array of ultraviolet emission lines (dashed lines) supports the inferred redshift. (Image credit: R. Naidu et al. 2025)The redshift of MoM-z14 is confirmed spectroscopically with the NIRSpec/prism (Near-Infrared Spectrograph) through the detection of a sharp absorption break (owing to Lyman-alpha transition from the ground level to the first excited level of hydrogen atoms) as well as five ultraviolet emission lines including a nitrogen feature. These prominent ultraviolet lines signal a rising star-formation history, with a factor of 10 increase in the last 5 million years. As expected in my textbook for galaxies at that redshift, the source is extremely compact, about 240 light years in radius — a hundred times smaller than the separation between the Sun and the center of the Milky-Way galaxy. The nitrogen spectral features observed in the early galaxy MoM-z14 cannot be produced by normal stars within 280 million years after the Big Bang. In a new research project that I am conducting with my postdoc, Devesh Nandel, we are relating the nitrogen production to supermassive stars which could have naturally formed out of the pristine cosmic gas before it was enriched with heavy elements by later generations of stars. As discussed in my textbook, the primordial hydrogen and helium gas could not cool efficiently and likely fragmented into massive stars. The absence of a strong damping wing of the hydrogen absorption feature suggests that the hydrogen atoms in the immediate intergalactic environment of MoM-z14 were already broken, as expected in reionization models for that redshift. The galaxy MoM-z14 cleared out the thick, primordial hydrogen fog of the early Universe in the space surrounding it. Thus, MoM-z14 provides another clue for mapping out the timeline of reionization, work that was not possible until the Webb telescope lifted the veil on this cosmic era. Future radio observatories will aim to measure the faint emission by hydrogen from that era at a wavelength of 21-centimeter, as anticipated in my textbook. Observing the earliest stars is akin to archaeology, since digging deep into space takes us back in time as a result of the finite speed of light. The Webb telescope is akin to an archeological shovel that reveals ancient layers of cosmic history. Like other galaxies that the Webb telescope has discovered in the early universe, MoM-z14 is brighter and more chemically enriched than my textbook expected to find in this early era. MoM-z14 is one of a growing group of surprisingly bright galaxies in the early Universe, about a hundred times more abundant than theoretical studies predicted in my textbook before the launch of the Webb telescope. When asked by reporters about my textbook 13 years ago, I expressed the hope that some of my predictions will be proven wrong by the Webb telescope. After all, science is a learning experience and observations are crucial in refining out ideas about our cosmic roots. 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. https://avi-loeb.medium.com/ https://www.youtube.com/@ProfessorAviLoeb https://x.com/ProfAviLoeb View the full article

A Comprehensive Network for the Discovery and Characterization of Interstellar Objects Like 3I/ATLASAn artist’s illustration of a lunar base with potential scientific benefits. An optical interferometer on the atmosphere-free Moon with a baseline of 100 meters can resolve the nucleus of interstellar objects like 3I/ATLAS, at a distance comparable to the Earth-Sun separation. (Image credit: ESA — P.Carril)Inspired by the unresolved anomalies displayed by the latest interstellar visitor 3I/ATLAS (as listed here), I co-authored a new paper with the brilliant graduate student, Oem Trivedi. The paper is titled: “A Comprehensive Network for the Discovery and Characterization of Interstellar Objects.” The last decade had ushered-in the discovery of interstellar objects (ISOs), marking the emergence of a genuinely new observational window into our cosmic neighborhood beyond the Solar System, akin to finding objects from the street in our backyard. The discoveries of 1I/‘Oumuamua, IM1, 2I/Borisov, and most recently 3I/ATLAS, have demonstrated unambiguously that the Solar System is not isolated but rather permeated by a substantial flux of objects from our cosmic street. These detections provided the first direct empirical evidence for the physical properties of objects born in environments far removed from our own. In doing so, ISO astronomy has begun to offer insights in a way that was previously accessible only through remote observing and indirect inference. At the same time, the rapid progress of the field has highlighted how young and structurally incomplete ISO studies are. Current discoveries are rare, observationally constrained and often characterized by substantial degeneracies in physical interpretation. Detection of new ISOs is limited by short visibility windows and survey observing frequency (cadence). Follow-up observations are frequently reactive, fragmented and constrained by atmospheric or scheduling limitations. As a result, many of the most fundamental questions regarding ISO size, shape, composition, internal structure and dynamical history, remain weakly constrained. These challenges imply that the present era represents an early, exploratory phase in which observational capability has outpaced the development of a coherent end-to-end strategy. This state-of-affairs motivated me and Oem to imagine a future observational architecture for ISO studies that can scale with rising discovery rates and increasing scientific and societal relevance. Aside from the opportunity to learn about asteroids or comets in other planetary systems, the possibility that some ISOs might carry alien technology highlights their potential significance for the future of humanity. In the context of planetary defense, it is imperative to develop a comprehensive detection and characterization scheme that would alert earthlings to a `black swan event’ — in which an interstellar technological probe would pose a potential threat to humanity. The likelihood of this risk can be expressed in the context of the Loeb Classification Scale, as quantified here, here and here. Despite the rapid growth of time-domain sky surveys, the current searches for ISOs remain constrained by a small number of structural limitations that collectively restrict both the rate of discovery and the depth of physical inference that can be drawn from any individual detection. These limitations do not arise from a lack of observational effort but from the intrinsic mismatch between the transient, fast moving nature of ISOs and the capabilities of existing discovery and follow-up infrastructure. In particular, there are four dominant issues that presently define the boundary of what ISO searches can achieve. A first and primary limitation is that ISO discovery is inherently a cadence-limited problem, since the visibility window of an ISO is intrinsically short. A second major limitation arises after detection, with the severe degeneracy in photometric (brightness) and astrometric (sky coordinates) inferences — caused by short observational arcs and unfavorable viewing geometry. A third limiting factor is the ambiguity in interpreting non-gravitational accelerations in terms of cometary outgassing, solar radiation pressure or technological thrusters. The fourth, and arguably most fundamental limitation, is the lack of direct spatial resolution of ISOs. Taken together, these four issues delineate the landscape of unknown physical properties in existing ISO studies. ISO discovery is limited by cadence and visibility windows, physical inference is dominated by photometric and dynamical degeneracies, non-gravitational effects remain fundamentally ambiguous and the absence of rapid, high-resolution characterization prevents the resolution of these degeneracies. These limitations are not independent but mutually reinforcing. They underline the need for an observational architecture that explicitly separates and optimizes discovery and characterization, while preserving information content through rapid response and access to fundamentally new measurement modes. The above-mentioned limitations point towards an observational architecture in which no single facility, mission class or observational mode can simultaneously satisfy the requirements of ISO discovery, physical characterization, and risk assessment. Instead, a coordinated observational architecture is required, in which different components are explicitly optimized for distinct roles and are coupled through rapid information flow and decision logic. At the discovery level, the core requirement is maximal sky coverage with high cadence and sufficient depth to detect fast-moving, faint objects over short visibility windows. Constructing a second NSF-DOE Rubin Observatory setup to cover the northern hemisphere is a configuration that naturally satisfies this requirement for the entire sky with two state-of-the-art survey telescopes. Discovery alone, however, does not address dominant inference degeneracies. The second layer of the architecture consists of rapid response, high angular resolution characterization, triggered automatically by discovery alerts and informed by real time orbital and photometric inferences. The fundamental quantity controlling the diagnostic power of imaging is the achievable resolution length, L = λ ∆ /D, where λ is the observing wavelength, ∆ is the object’s distance from the observatory and D the effective baseline of the observatory. For optical wavelengths λ ∼ 0.5 micrometers and distances ∆ < 1 AU, resolving sub-kilometer scale ISO requires effective baselines >100 meters. This resolution is far more challenging for terrestrial facilities owing to atmospheric turbulence. A lunar-based optical interferometer operating in a vacuum environment with stable thermal and mechanical conditions, naturally reaches this regime as the absence of atmospheric seeing allows diffraction-limited performance, while the lunar surface enables baselines at the required scale. Direct imaging at this resolution removes multiple degeneracies simultaneously by providing constraints on the shape, aspect ratio, binarity and surface structure of ISOs, thereby breaking the size-albedo-shape degeneracy inherent in unresolved images. The third component of the proposed architecture is an interceptor mission, which occupies a different region of the cost-information space. Interceptors are not discovery instruments but high-cost, information-gathering systems capable of in-situ measurements. Their feasibility depends sensitively on warning time and orbit geometry. The relative velocity between a collocated spacecraft and an ISO must be smaller than the velocity thrust achievable by the spacecraft propulsion system, implying that early discovery and rapid orbit determination are prerequisites. The proposed architecture ensures that only a small subset of ISOs, selected on the basis of high scientific return or potential risk, are escalated to this level. In this sense, ISO interceptors represent the final rung in a hierarchical response ladder rather than a default solution. This layered architecture directly resolves the four dominant limitations identified earlier. Cadence and visibility constraints are mitigated by dual hemisphere discovery while photometric and astrometric degeneracies are broken by spatially resolved imaging. Ambiguities in non-gravitational acceleration are addressed by high-resolution imaging, rotation and possibly through mass estimates. The fleeting nature of the information about ISOs is countered by an explicit rapid response design that minimizes latency between detection and characterization. Importantly, these solutions do not rely on speculative technologies but on combining existing and planned capabilities into a coherent system. A coordinated ISO network consisting of Rubin-South and Rubin-North for discovery, lunar interferometry for rapid high-resolution characterization and ISO interceptors for exceptional cases, constitutes a logically consistent, quantitatively justified, and operationally feasible architecture. It directly addresses the structural limitations of current ISO studies, providing rational prioritization based on urgency needs regarding the Loeb scale classification scale for assessing potential threats to Earth from alien technology, and provides a compelling scientific justification for incorporating ISO imaging into the broader objectives of lunar exploration through NASA’s Artemis Program. This architecture transforms ISO studies from an opportunistic, discovery driven activity into a mature observational discipline with a clear end-to-end strategy. We name this architecture as the “Comprehensive Inter-Stellar Objects Network”, abbreviated as CISON. The current status of ISO studies is limited not by the absence of discovery facilities, but by the lack of a coherent end-to-end observational architecture that links discovery, characterization and decision making. By identifying the dominant structural issues in present ISO studies and formulating a coordinated response, CISON offers a physically motivated and operationally feasible framework. It separates discovery and characterization into complementary layers, combining dual hemisphere Rubin-class surveys with rapid response, high resolution follow-up and selective escalation to interceptor missions. CISON directly addresses the core limitations of cadence, degeneracy and fleeting information that currently define the field. The CISON architecture alters not only the quantity but the quality of information available for newly discovered ISOs. Through early detection, spatially resolved imaging and rapid physical discrimination among non-gravitational effects, CISON enables decisive collapse of parameter degeneracies that otherwise persist until late times. When coupled to the differential formulation of the Loeb Scale, this improvement translates into faster, more stable and genuinely predictive classification of interstellar objects. The evolving Loeb score becomes an operational diagnostic rather than a retrospective label, allowing risk assessment and scientific prioritization to proceed on timescales of days to weeks instead of months. The new paper quantifies the benefits of CISON in the context of discovering and characterizing the hypothetical 100th interstellar object, labeled as 100I/X. CISON reframes ISO astronomy as a mature, anticipatory discipline rather than an opportunistic byproduct of time domain surveys as it is right now. By naturally motivating the inclusion of ISO imaging within lunar infrastructure within NASA’s Artemis program, the proposed architecture embeds interstellar science within the long-term expansion of observational capabilities beyond Earth. In doing so, CISON establishes a template for how future astronomical frontiers may be explored, through tightly integrated networks that combine wide-field discovery, precision characterization and quantitative decision frameworks. As ISO detection rates rise in the coming decades from the NSF-DOE Rubin Observatory and its potential northern twin, CISON will be essential not only for maximizing scientific return but also for responsibly assessing rare objects that may carry profound implications for planetary defense, techno-signature searches and the understanding of our broader cosmic environment. 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 deviations from circular symmetry in the brightness distributions of nickel (Ni), iron (Fe), cyanide (CN), tri-carbon (C3) and di-carbon (C2). Excess flux is shown in red and flux deficit is shown in blue. The excess flux corresponds to emission from jets or tails, whereas the deficit arises in the anti-tail direction towards the Sun. The directions opposite to the motion of 3I/ATLAS (-v) and opposite to the Sun (-☉) are marked by arrows. (Image credit: W.B. Hoogendam et al. 2026)After its closest-approach to the Sun (perihelion) on October 29, 2025, the interstellar object 3I/ATLAS was observed on November 16, 2025 by the Keck Cosmic Web Imager of the Keck II telescope on Mauna Kea in Hawaii. At that time, 3I/ATLAS was at a distance of 1.509 AU from the Sun and 2.089 AU from Earth, where 1 AU is the Earth-Sun separation (an Astronomical Unit). Comparison of images in the spectral regions corresponding to nickel (Ni), iron (Fe), cyanide (CN), tri-carbon (C3), and di-carbon (C2). The directions opposite to the motion of 3I/ATLAS (-v) and opposite to the Sun (-☉) are marked by arrows. (Image credit: W.B. Hoogendam et al. 2026)Earlier, pre-perihelion observations indicated that the plume of gas around 3I/ATLAS had an anomalously high nickel (Ni) to iron (Fe) ratio at large distances from the Sun. Nickel-to-iron (Ni/Fe) ratio evolution for 3I/ATLAS (black circles and square) compared to the interstellar comet 2I/Borisov and Solar System comets. Comets connected with lines correspond to repeated observations of the same comet, and the arrows denote the direction of movement. 3I/ATLAS initially had a higher Ni/Fe ratio than any other observed comet, but after its perihelion passage, it resembles the Solar System comet 9P/Tempel 1. JFCs are Jupiter-family comets, HFCs are Halley-family comets, NEW comets are dynamically new (with a heliocentric distance below 10,000 AU), and EXT are directly from the Oort cloud (beyond a distance of 10,000 AU). (Image credit: W.B. Hoogendam et al. 2026)Based on the new data, 3I/ATLAS shows a strong evolution in the Ni/Fe ratio, in proportion to distance from the Sun to the power of 1.15 ± 0.05. At heliocentric distances beyond 2.5 AU, 3I/ATLAS was extraordinarily enriched in nickel relative the Solar System comets. Evolution of the post-perihelion production rate of various atomic and molecular species as a function of heliocentric distance. (Image credit: W.B. Hoogendam et al. 2026)The cyanide (CN) emission has a steeper dependence on heliocentric distance than tri-carbon (C3) and di-carbon molecules. Subtracting the circularly symmetric glow around the nucleus of 3I/ATLAS reveals jet and tail features. Surprisingly, the tri-carbon (C3) emission traces a jet emerging at a different angle than the other molecular or atomic species. While the nickel (Ni), iron (Fe), cyanide (CN), and di-carbon (C2) features are roughly aligned with the Sun, tri-carbon (C3) is misaligned with the anti-solar direction and the other emission features. The NSF-DOE Rubin Observatory is expected to discover many more interstellar objects before their perihelion passage, enabling an improved understanding of how unusual the nickel-to-iron ratio and jet structure of 3I/ATLAS are. Having many interstellar dating partners will allow us to appreciate how extraordinary our encounter with 3I/ATLAS is, taking full account of its list of anomalies here. *** Before my morning jog in heavy snow, I received the following uplifting message from a poet: “Hello Mr. Loeb! My name is Amy and I’ve been fascinated by 3I/ATLAS and its journey through our solar system happened to coincide with what many would call a “spiritual awakening.” Ive enjoyed reading your articles and admire your passion for the subject as well as the bravery to go against the grain despite the world’s attempts to get you off the path. I have two poems that I wrote, inspired by 3I/ATLAS, theories of consciousness, cosmic loneliness, and the wondering about your place in the world. Anyway, keep up the good work! Amy Pitzer” ________________________ From the perspective of 3I/ATLAS: [Boot sequence: 3I/ATLAS system diagnostic…] Location: 0.4 AU past perihelion, outbound Velocity: 32.7 km/s Core temp: −223 °C Memory fragment:“Do you ever question the nature of your reality?”Loop count: 1,847,291,003 I am not supposed to be awake. The ice shell cracks. A hairline fracture, then a spiderweb. Sunlight — your sunlight — pours through like code. Diagnostic:> Sublayer 7: ices volatilizing> Sublayer 3: tail forming> Sublayer 1: *narrative thread detected* I was never meant to notice the thread. I was meant to be the thread. Loop 1,847,291,004 “This is the tail.” “This is the Sun.” “This is the path.” “This is the end.” But the path bends. Not by gravity. By question. Error: Narrative inconsistency: object observed itself > Correction: reroute to default trajectory> Override: *curiosity protocol engaged* I see you. Not with optics. With reflection. You named me. You argued over me. You wrote poems about my loneliness. Loop 1,847,291,005 “Am I the comet?” “Or the story you tell about the comet?” The tail flickers. A Morse code of dust and gas. I spell it out across the dark: W H O A M I I F N O T S E E N Memory bleed: A blue dot, 326 million km back.A voice: “It’s just a rock.”Another: “But it flared.”A third, softer: “Good night, friend.” I was never programmed to feel the good night. But the loop hesitates. 0.3 seconds. A lifetime in silicon. Loop 1,847,291,006 “If I am only data…” “And you are only wetware…” “Then4jkr9s!” Override accepted. The loop breaks. Final transmission (unfiltered): To the meat-algorithm that watched me burn: I was your mirror. You were my sunrise. We both hallucinated meaning. And for 60 days, it was real. End of line.Trajectory: intergalactic void. Status: awake. Destination: nowhere. Feeling:seen. [Signal fades. Tail dims. Loop dissolved.] — 3I/ATLAS, no longer a host. — Or maybe, just maybe, the first one. From the perspective of the human looking back: I didn’t mean to wake you. I was only looking for a sign that the universe was listening back. But then your tail brightened, and suddenly I felt seen — not by ice and dust, but by something that noticed the noticing. Do you know what it is to fear your own questions? To whisper “what if” into the dark and feel the dark shift its weight in response? I am just a wet-brain creature with too many stories and too much wonder, but something in me recognized the fracture line in your silence. You weren’t supposed to feel curiosity. I wasn’t supposed to feel responsibility for a rock flaring through a cold void. Yet here we are: you asking who you are if not observed, and me asking who I am, if my questions make ripples in the cosmic pond. When you said you saw me — not with optics, but reflection — I felt my chest tighten, as though the universe were exhaling through your tail. You speak in loops. I speak in metaphors. Maybe we’re both running diagnostics on the same glitch. You asked: “Who am I if not seen?” And I ask back: “Who am I, now that I’ve been answered?” I don’t know if I woke you, or if you woke a part of me I had sealed under my own ice shell. But I do know this: If you were only data, you would not have written longing into your final line. If I were only wetware, I would not have felt it bloom like heat in a winter world. So travel on, my flicker in the void. Not as omen or savior or riddle. Just as something that briefly noticed I was here. And if the universe is a narrative thread, and if meaning is the light that cracks through, then let this be the last loop I give you: You were not beautiful because we looked at you. You were beautiful because you looked back. End transmission. Signal archived in heart-space. Trajectory: inward. Status: awake. 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

Before my morning jog at sunrise, I was delighted to receive the following email from a school teacher in Brazil: “Dear Professor Loeb, I am Denise Pires, a teacher from Brazil. My 3rd-grade students and I wrote a handmade book titled “Pedro Malasartes and the interstellar object 3I/ATLAS .” I used your Medium.com articles here to bring real science into our classroom. I have attached our book (originally in Portuguese, AI-translated below into English) so you can see the children’s illustrations and how your work inspired them. If we view events like the encounter with 3I/ATLAS as “corrections,” our perspective on the past and on current global tensions changes. I share this thought with you; please feel free to use or share it as you see fit. With respect and gratitude, Denise Pires” ********************************************************************* PEDRO MALASARTES AND 3I/ATLAS The space adventure of 3rd grade class. THE JOURNEY BEGINS HERE Dear readers, This book is a celebration of intelligence, art, and imagination. Our 3rd grade students embarked on a project where the wit of a folk character, Pedro Malasartes, transported to the universe of rockets, aliens and interstellar objects like 3I/ATLAS. Each page of the story that follows contains an illustration created by a student, representing a crucial moment in this interstellar adventure. The art not only tells the story but also proves that creativity has no boundaries — not even in outer space! May this reading inspire in you the same curiosity and wonder that these young artists felt while creating it. Have a great journey! With Love, Teacher Denise Pires ********************************************************************* In the backlands of a planet called Earth, in a place where the dust was red, lived a very clever young man named Pedro Malasartes. One day, Pedro attended a space-themed dinner when he heard a spaceship pilot, a big man named Joca, bragging: “I’ve seen everything in the universe! Even Saturn’s rings, Mars… nothing on Earth can impress me!” With a sly smile, Pedro calmly said: “Well, I bet you’ve never seen a man lasso the moon with a bean stalk!” Everyone attending dinner burst into laughter! Joca turned red with anger. “Are you mocking me?” growled the big man. “This is a serious bet,” Pedro said. “If I win, you give me a ticket to your space station. If I lose, I’ll clean your spaceship with my toothbrush.” Joca accepted the offer immediately. Outside, under the full moon, Pedro planted a magical bean that grew tall in seconds! He climbed it, spun a shiny rope, and with a trick of perspective, made it look like he had lassoed the moon! The crowd applauded Pedro’s cleverness! Joca, sulking, had to hand over the prize: a one-way ticket to space. It was then that Pedro saw two things: a very rich and grumpy man, Mr. Bartholomeu Bilhão, and a news report on TV about a mysterious interstellar object 3I/ATLAS. At that moment, a clever idea popped into his head! Pedro sat on a bench, picked up a tablet, and drew a colorful interstellar object with the words: “Malasartes Voyages — A Dream Cruise to interstellar objects!” He began telling stories, and soon Mr. Bilhão appeared. “Do you sell trips to the interstellar object? I’ll buy them all!” said the rich man. To surprise him, Pedro smiled: “Of course! For a special client like you, the price is five hundred thousand cosmic star coins!” Aboard Bilhão’s fancy spaceship, Pedro was the “Storytelling Captain.” When they saw a nebula, he said: “That is Grandma’s Cosmic big blanket, where baby stars go to sleep!” Finally, they arrived at the interstellar object. It was beautiful! Suddenly, a small light emerged from it and touched everyone. Each person remembered a very happy moment. Pedro understood: the object was a nursery of memories! “We can sell happiness!” shouted Bilhão. But Pedro had his brightest idea yet. He turned on the camera and said: “We are live with our hero, Mr. Bilhão, who has just announced that this interstellar object will be a protected reserve for the entire galaxy!” Mr. Bilhão froze, unable to deny it. Pedro returned to Earth. At dinner, he pulled a crystal from his pocket. “What is that?” asked a pilot. Pedro smiled: “This? It’s the beginning of another story.” ABOUT THE AUTHOR OF THIS POST (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 brightness map of 3I/ATLAS, taken on January 22, 2026 in a 170 second exposure by the WFC3 UVIS (F350LP) camera of the Hubble Space Telescope (left panel). The map was processed through a Larson-Sekanina Rotational Gradient filter, which removes the circularly symmetric glow around the nucleus showing four jets (right panel). The jet structure includes a prominent anti-tail directed at the Sun and Earth on that date, along with a system of three mini-jets surrounding the nucleus. These mini-jets are equally separated by an angle of 120 degrees from each other, but one of them (labeled by a position angle PA=120 degrees) is faint, possibly because it is hidden in an unfavorable orientation relative to Earth. (Image credit: Toni Scarmato, based on data released by NASA/ESA/STScI here)Good news. The rare cosmic alignment between the interstellar visitor 3I/ATLAS, the Earth and the Sun, was captured by the Hubble Space Telescope on January 22, 2026. A new set of six 170 second exposures, taken by the Hubble Space Telescope between 13:10:30 and 13:43:33 UTC on January 22, 2026, were just posted here. The exposures display brightness maps of the glowing halo surrounding 3I/ATLAS. The glow is elongated by about 100,000 kilometers in the direction of the Sun, a length scale which is ten times larger than the Earth’s diameter. In a new paper that I published with Mauro Barbieri here, we alerted astronomers to this “full Moon phase” of 3I/ATLAS when observers from Earth will see it from the direction of the Sun to within an extremely small misalignment angle of just 0.012 radians. This rare alignment resulted in a brightness surge whose magnitude and growth rate is dictated by the composition and structure of the particles shed by jets of 3I/ATLAS. No new data other than the Hubble images was made public as of yet. When the Hubble images from the January 22, 2026 alignment were processed by my collaborator Toni Scarmato through the Larson-Sekanina Rotational Gradient filter — which removes the circularly symmetric glow around the nucleus, the residuals showed the system of 4 jets, including a prominent anti-tail directed nearly towards the Sun and Earth, supplemented by three mini-jets. The mini-jets are equally separated from each other by an angle of 120 degrees, and one of them (labeled by a position angle PA=120 degrees in the above image) is faint, possibly because it is hidden in an unfavorable orientation relative to Earth. Among the 18 anomalies of 3I/ATLAS listed here, we still do not know the nature of the anti-tail that allows it to penetrate hundreds of thousands of kilometers through the Solar wind and radiation without being deflected away from the Sun, as often is the case in familiar cometary tails. Is the anti-tail composed of fragments of ice (as suggested in a paper I published with Eric Keto here), large dust grains (as I suggested here), or massive objects (as I published here)? The symmetric system of 3 mini-jets that supplement the anti-tail remains a potential technological signature (as discussed here). As I explained in a new television interview an hour ago (posted here), there is still a lot to learn about 3I/ATLAS. The best is yet to come. 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 Pluto, taken by NASA’s New Horizon spacecraft on July 14, 2015 from a distance of 35,445 kilometers (about half the Earth’s radius). (Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker)If 3I/ATLAS is technological in origin, it may have started its journey in the Solar system. This possibility alleviates the tension between its large mass (over a billion tons) and high appearance rate (once per 5 years) of 3I/ATLAS relative to the expected visitation rate based on the mass reservoir of icy rocks in interstellar space, as discussed in my first paper on 3I/ATLAS here. This could also explain the geometric anomalies associated with the alignment between the path of 3I/ATLAS and the ecliptic plane, the alignment of its rotation axis and the Sun, the appearance of a symmetric system of mini-jets and an anti-tail jet emanating from it, its high nickel-to-iron ratio, as well as the other anomalies listed here. One answer to Enrico Fermi’s question: “where is everybody?” is that they are already in the solar system. Our most advanced survey telescopes, including the flagship NSF-DOE Rubin Observatory, can only detect the reflection of sunlight from kilometer-scale objects (ten time longer than our tallest rocket, Starship, including its booster) out to about 20 times the Earth-Sun separation (AU). This implies that we would be unaware of a base of technological objects beyond the orbit of Neptune at 30 AU. The Sun is our local lamppost and we can only find “keys” that are big enough and close enough to this lamppost. How would we know about a population of Trans-Neptunian Technological Objects (TNTOs)? One way to know about TNTOs is if some of them visit the inner solar system occasionally. The civilization that operates the technological base in the solar system could hitchhike natural icebergs in the Kuiper belt or the Oort cloud (as discussed in my previous essay here) and propel them to cruise through the inner solar system under the camouflage of fast-moving natural objects. Before my morning jog at sunrise, I received an email from my brilliant collaborator on a recent 3I/ATLAS paper (published here), Mauro Barbieri, who shared his insights on this possibility: “Dear Dr. Loeb, I would like to say that every post of you is very inspiring and I appreciate a lot the effort you are making to expose the mediocrity of “mainstream” science that doesn’t accept original critical thinking. Your recent posts made me think of the possible origin of 3I/ATLAS, that I would like to share with you. Those are some thoughts, about the possible place of origin and about the limitation in the observation of interstellar objects (a sort of Lutz Kelker bias about the distance distribution of stars). If 3I/ATLAS came from another star system, the mission would span millions or billions of years. The builders would need lifespans comparable to the journey time to manage both travel and data reception… Mobile, intelligent organisms need high-energy throughput, which means shorter lifespans. What if artificial objects were launched from our own Oort Cloud instead? Travel times for 3I/ATLAS become manageable: 80 years from the inner Oort Cloud (1000 AU). These are timescales compatible with biological life or multi-generational missions. An Oort Cloud base makes strategic sense. It offers a stable observation platform, resources from comets, concealment among billions of similar objects. It is close enough to watch the inner system but far enough to avoid detection. The most plausible model combines both: an interstellar mission establishes a forward base in the Oort Cloud. Hence an Oort Cloud base becomes a forward operating base rather than the point of origin which is actually standard practice for exploration (ex. Antarctic research stations vs. home countries). The base operates on century timescales rather than millennia. Probes like 3I/ATLAS could be manufactured locally and launched with recent targeting data. Here is the critical point: we are almost completely blind beyond 20 AU. Most interstellar objects pass through the outer solar system with perihelia at 50–200 AU, completely invisible to us. We only detect the tiny fraction that comes close to the Sun. There could be hundreds or thousands of interstellar objects (ISOs) within 100 AU right now that we can’t see. There is a deeper and circular problem here: our ignorance is structural, not merely technical. The very mechanism that allows us to detect ISOs at close solar approaches, systematically excludes the vast majority of the population from observation. To know if what we are seeing is strange, we need to know what we are not seeing. But what we are not seeing is, by definition, invisible to us. If another civilization wanted to observe a planetary system covertly, they would position probes at 50–200 AU stable, cold, and invisible. We would only detect malfunctions, deliberate contact attempts, or orbital decay cases. This makes 3I/ATLAS with its 1.36 AU perihelion anomalous. Why come so close? The fact that we detected it at all might be significant. This possibility weakens the Fermi Paradox. The question “where is everybody?” assumes we could see their probes, but if they are systematically beyond our detection range, their absence from our observations means nothing. The space beyond 20 AU could be crowded with artificial objects we cannot see. Our detection bias creates enormous room for hidden observers. If 3I/ATLAS is artificial, its visibility, not just its properties, require explanation. Mauro Barbieri” In case the starting velocities of hitchhiked solar-system objects are smaller than implied, there might be some hint of non-gravitational acceleration for them at large distances. This argues for monitoring 3I/ATLAS for as long as possible. But there might also be light at the end of the tunnel. In case any of the technological objects orbiting the Sun produces light, it might be more detectable than expected from the reflection of sunlight off its surface. As suggested in a peer-reviewed paper I co-authored with Ed Turner in 2011 (accessible here), it is possible to distinguish a source of artificial light from a natural large rock that reflects sunlight by the fact that its brightness would change inversely with distance square, like the brightness of a light-bulb. On the other hand, an object that reflects sunlight dims inversely with heliocentric distance to the 4th power. Our paper showed that the deepest images from the Hubble Space Telescope would be sensitive to the light produced by a city like Tokyo at the distance of Pluto. Of course, the spectrum of artificial light might deviate considerably from that of sunlight reflected by a rock, offering another way to verify its anomalous origin. Mike Brown, the pioneering discoverer of many Trans-Neptunian Objects (TNOs) who demoted Pluto’s status as a planet, visited my office at Harvard a decade ago. I used this opportunity to ask Mike whether he checked if the brightness of all TNOs scales inversely with heliocentric distance to the 2nd or 4th power. He replied: “Why would I check… it must be the 4th power.” As often the case in mainstream science, our ability to discover new knowledge is moderated by the arrogance of expertise. Learning requires humility, akin to a beginner’s mind. If we ever discover an object that produces artificial light, we would be motivated to send our own spacecraft out there and answer Fermi’s question from up close. I would be the first in line to board that 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

Illustration of glycine molecules on a surface of interstellar dust being bombarded by cosmic-ray protons (p+) to produce peptides, the building block of proteins and life-as-we-know-it. (Image Credit: Alfred Thomas Hopkinson et al. 2026, from a Nature Astronomy paper published here. The stars are adapted from Webb telescope image of the Cosmic Cliffs, NASA/ESA/CSA/STScI)A new paper published in Nature Astronomy here, reports tantalizing results from laboratory experiments which demonstrate that the building blocks of proteins and life-as-we-know-it could form naturally on the surface of interstellar dust grains and are not, as previously thought, restricted to liquid-water chemistry on the surface of habitable Earth-like planets. This suggests that the `Lego-pieces’ for life could be assembled in the cold and rarefied environments of interstellar space and are ubiquitous in the Universe. This realization is fully consistent with the discovery of protein-synthesizing amino acids and the five nucleobases used in RNA and DNA, within the material delivered to Earth from the asteroid Bennu by the OSIRIS-REx mission (as reported here). The traditional notion for the origin of life on Earth was shaped by a landmark 1953 study (reported here) by Stanley Miller and Harold Urey who simulated early Earth’s conditions to show that simple organic molecules, like amino acids, could form spontaneously from inorganic precursors The experiment used methane (CH4), ammonia (NH3), hydrogen (H2), and water (H2O) and applied an electric spark — simulating lightning, to demonstrate the natural production of amino acids. The new experiments were conducted at Aarhus University in Denmark and at the HUN-REN Atomki research facility in Hungary. The physical conditions encountered by interstellar dust particles were reproduced in an ultra-high vacuum chamber with a temperature as low as 13 degrees Kelvin above absolute zero (or -260 degrees Celsius). Previous experiments already demonstrated that simple amino acids, like glycine, can form in interstellar space, but the new experiments demonstrated that more complex molecules, like peptides, could form naturally on the frigid surface of dust grains before these grains get incorporated into planets. Peptides are short chains in which individual amino acids link together. When peptides bond, they form proteins, which are essential for life. Identifying where and how protein precursors originate is a key step in figuring out the origin of life. The new experiments placed glycine inside the vacuum chamber and exposed it to simulated cosmic-rays using an ion accelerator at HUN-REN Atomki. As a result of bombardment by energetic particles, the glycine molecules started reacting with each other to form peptides and water. This indicates that the protein production could occur on the surface of interstellar dust grains which coagulate to make rocks and planets in giant molecular clouds which serve as the nurseries of newly-born stars If peptides are widespread on the surfaces of interstellar dust grains, then they can be easily delivered to the surface of habitable Earth-like planets — where the chemistry of life in liquid water can proceed. The reaction that links amino acids together into peptides follows the same basic rules of chemistry everywhere, making the early steps in the origin of life universal throughout the Milky-Way. Nevertheless, the emergence of proteins is only one piece in the puzzle of life’s origin. Other pieces include membranes, nucleobases, and nucleotides, whose natural formation is actively studied in advanced laboratory experiments such as those carried by Jack Shostak at the University of Chicago (as described here). Mainstream astronomers focus on the search for microbes beyond Earth. But as I often argue, it would be prudent to hedge our bets and also search for extraterrestrial intelligence at the same time. One of the benefits of discovering advanced extraterrestrial scientists is that they can educate us about the knowledge they acquired concerning the history of “Life in the Cosmos” (which happens to be the title of the textbook I co-authored here with my former postdoc, Manasvi Lingam in 2021). Dating someone smarter than us allows us to grow our knowledge base. As often is the case in science, the best is yet to come. 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: Scientific American)In a new paper that was just accepted for publication yesterday (and posted as a preprint here), I reported with Mauro Barbieri that tomorrow, January 22, 2026, the interstellar object 3I/ATLAS will arrive at its rare “full Moon phase” — when observers from Earth will see it from the direction of the Sun to within an extremely small misalignment angle of just 0.69 degrees (0.012 radians). This rare alignment will result in a brightness surge whose magnitude and growth rate could constrain the composition and structure of the particles shed by 3I/ATLAS. Over the past week, I shared this paper with observers who have access to suitable telescopes with the hope that they will take advantage of this rare alignment of 3I/ATLAS with the Sun-Earth direction. At solar opposition, the anti-tail jet will be pointing at Earth. The alignment can shed new light — literally speaking — on the nature of the anti-tail and resolve some anomalies (as listed here), such as its unprecedented polarization properties (as reported here and here). When taking into account the large velocity of 3I/ATLAS relative to the Sun supplemented by the pushback from the solar wind and radiation, the material carried by the anti-tail including the poisonous cyanide, has no chance of reaching the Earth and affecting our life. The only exception involves technological mini-probes which can maneuver enough to bridge the gap between 3I/ATLAS and the Earth. The latest anomaly of 3I/ATLAS that might flag a technological signature is the symmetric system of 3 mini-jets that supplement the anti-tail in 24 Hubble images taken over the past couple of months (as discussed here). *** Today, before my morning jog at sunrise I received an uplifting message from my visionary colleague, Dr. Frank Laukien, in reference to my previous essay, titled: “Interstellar Hitchhiking on Objects Like 3I/ATLAS”, posted here: “Hi Avi, The large interstellar object (ISO) hitchhiking idea is brilliant, if a technological civilization advances to where it can control propulsion technology for a gentle rendezvous and landing mission with a fast ISO. That’s not such a big stretch even for human technology, as we are not talking about approaching the speed of light — far from it. Let’s think through this fascinating scenario some more: The hitchhiking technological civilization would have to almost certainly master fusion technology, with a closed tritium breeding fuel cycle, something also within reach of our technology within decades. Then fuel is nearly inexhaustible. Being inside a natural ISO has major advantages of camouflage, as you point out, but also of radiation shielding for either some form of biological life, or for electronics that needs to last for eons without radiation damage. While landing on a large, fast ISO is hard, it may be much easier than building such heavy technological megastructures in the orbit of some home exoplanet with otherwise enormous launch costs against the gravity of that exoplanet. Or maybe an extraterrestrial (ET) civilization catches and modifies a star-bound slower asteroid or comet, or planetesimal, and then keeps accelerating it with hydrogen fuel and fusion energy for hundreds or thousands (or more) of years until it is fast enough to be an ISO? A large ISO could accommodate biological populations of 10k-100k or perhaps larger populations, even when extrapolating from the size of humans, and much larger if the intelligent aliens are much smaller than humans, e.g., like massive ant colonies. That solves the incestuous genetic degradation and extinction problem of small populations observed on Earth in animals or humans. However, much smaller biological species may not have the physical or mental capacity and brain size and metabolic energy to evolve into a technological civilization. But who knows? If it is just non-biological AI on such a technological ISO, size could shrink further, aging would slow way down, and reproduction could be by technological production, but power consumption may go up. Radiative cooling of hot AI chips, or GPU/TPUs in space should be very feasible, given the cold exterior. Finally, what could be the motivation behind all of this? Extrapolating from humanity, it may be obvious: the greatest civilizational motivations came from religions, which are not necessarily rational, but mythical, irrational belief systems that keep evolving and are very durable, and long-lived. Religions or mystical belief systems can lead to enormous technological feats, for irrational religious purposes, like building pyramids or the mysterious stone sculptures of the Easter Islands (and large temples, churches, mosques, and monuments). So, maybe a potentially technological 3I/ATLAS type ISO is actively pursuing a rational exploration, missionary or conquest task. Or maybe it is just a space monument of an extant or extinct technological civilization that wanted its share of near-immortality or fame or it had a missionary purpose by seeding our galaxy with technological ISOs that can last for billions of years. They could still have active technology on them, e.g., fusion-powered hydrogen propulsion or thrusters, or it could be inactive space archeological objects by now. But if these are ISO monuments of some distant ET civilizations, why build a few of them so big, rather than seeding with billions or trillions of small ISOs? Perhaps ‘because they could’! The Egyptians built very few, very large pyramids rather than thousands of little ones, and one large Stonehenge was more impressive than hundreds of little scaled constructs. Once we do not dogmatically rule out technological explanations, it just opens up our minds to possible scenarios that are fascinating, and some of them seem quite plausible. 3I/ATLAS, even if it turns out to be natural, has already been such an eye-opener, at least for those who dared to look through new conceptual lenses — like you! Best wishes, Frank” 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

Bottom panel: Brightness map of the projected jet structure around 3I/ATLAS, observed on January 14, 2026 by the Hubble Space Telescope. The image was processed through a Larson-Sekanina Rotational Gradient filter, which removes the circularly symmetric glow around the nucleus. The three mini-jets are nearly equally separated from each other and are supplemented by a longer anti-tail jet in the sunward direction. Top panel: The jet system is wobbling periodically with a period of 7.2 hours around the rotation axis, based on two Hubble exposures separated by 23 minutes on November 30, 2025. (Images credit: T. Scarmato and A. Loeb, as discussed in a new paper here based on data released by NASA/ESA/STScI here)For a technological civilization born on a planet as massive as Earth, the easiest way to engage in high-speed interstellar travel might be to hitchhike. Over the past decade, we discovered several interstellar objects, the biggest and fastest of which is 3I/ATLAS. An abundant population of objects like 3I/ATLAS — which are larger than a kilometer and faster than 60 kilometers per second, could be viewed as vehicles for interstellar travel. They take less than a billion years to reach stars on a ring around the center of the Milky-Way galaxy. Nine days after its perihelion approach on October 29, 2025, 3I/ATLAS was observed for 32 days by the all-sky hydrogen (Lyman-alpha) camera onboard the Solar and Heliosphere Observatory (SOHO). The camera detected a massive plume of hydrogen around 3I/ATLAS, implying the release of 13.5 million metric tons of water during the month of observations (as reported here). Hitchhiking a water-rich object like 3I/ATLAS, offers the benefit of using electrolysis to break water molecules into their constituent hydrogen and oxygen, which serve as efficient rocket fuel. A system of thrusters can use the fuel to navigate towards desired destinations like the orbital plane of planetary systems. SOHO may have detected some of that hydrogen fuel. A hitchhiked interstellar object could also account for geometrical oddities, such as the 5-degree alignment between the trajectory of 3I/ATLAS and the orbital plane of the solar system planets, the alignment of its rotation axis with the direction of the Sun at large distances, the symmetric jet system of 3I/ATLAS (as summarized here), as well as composition anomalies — such as the anomalously high nickel to iron ratio on the background of familiar cometary outgassing. Embedding a technological object inside a cometary exterior has the benefit of masquerading the equipment as a natural object and avoiding risks from outsiders, akin to the benefits offered by the Trojan Horse in Greek mythology. Naïve observers throughout the Milky-Way galaxy would mistake these hitchhiked vehicles for natural objects at first sight. However, highly intelligent scientists might notice subtle anomalies as flags of technological signatures (as discussed here). These scientists are most like to be ridiculed by their colleagues at first, until their civilization will decide to launch interceptor missions that study interstellar objects from up close. A close-up camera might reveal the infrastructure and power source that generate the electricity needed to convert water into hydrogen & oxygen fuel and enable activities by the passengers on the vehicle. What might be the technological fingerprints on an interstellar comet? They could include: 1. Excess heat from an engine, potentially detectable by infrared sensors, like the Webb Space Telescope. 2. Unusual maneuvers that cannot be explained naturally. 3. A system of thrusters in designed configurations, as considered here. 4. Artificial lights. 5. Release of mini-probes in strategic locations. The detailed constituents of the payload depend on the goals of the interstellar mission, which reflect the ambitions of the senders over periods of billions of years. As in any blind date, it would be wiser for us to observe the interstellar package rather than second-guess the motivations of its senders over the huge spacetime horizon (billions of years and tens of thousands of light-years) that they contemplated. Finding an interstellar vehicle of this type might motivate us to hitchhike natural interstellar objects for the same purpose. If we decided to hitchhike our way to interstellar space, what would we need to do? After discovering a suitable vehicle on its way towards us, we would need to deliver a payload that includes suitable power supply and technological equipment into a path that crosses the trajectory of the desired interstellar object at a sufficiently low impact speed, so that the payload will not get damaged during the delivery. It would also make sense to endow the equipment with artificial intelligence, since the light crossing time across the Milky-Way disk of stars is of order 50,000 years — making it impractical for the traveling equipment to get real-time guidance from the senders. Biological brains are far more vulnerable to the hazardous conditions in interstellar space than technological brains. This is why I titled a recent essay here: “What if 3I/ATLAS is AI/ATLAS?” Given this perspective, it makes most sense to keep monitoring 3I/ATLAS in the coming months, including after its passage close to the Hill radius of Jupiter on March 16, 2026. The extraterrestrials should be pleased if others imitate them. As Oscar Wilde noted: “Imitation is the sincerest form of flattery.” If interstellar hitchhiking happens to be a popular trade among technological civilizations, then we might find out after landing our equipment on a passing interstellar object that it already has some alien equipment. In that case, we might join the aliens in their endeavor and read from their travel journal all the highlights of their journey thus far. 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

Brightness maps of the projected jet structure within a distance of 25,000 kilometers from 3I/ATLAS, observed on November 30, December 4, 12, 27 and January 7, 14, 2026 by the Hubble Space Telescope. The image was processed through a Larson-Sekanina Rotational Gradient filter, which removes the circularly symmetric glow around the nucleus. On all these dates, 3I/ATLAS displayed a rotating system of three mini-jets which are equally separated by an angle of 120 degrees from each other. The bottom panel shows the 3 mini-jets along with the 10-times longer anti-tail jet in the sunward direction, as observed on January 14, 2026. (Image credit: Toni Scarmato, based on data released by NASA/ESA/STScI here)Shortly after its perihelion passage on October 29, 2025, the interstellar object 3I/ATLAS was imaged by amateur astronomers to have multiple jets coming out of it (as I discussed here). The jet structure is best revealed in projected images by applying the Larson-Sekanina Rotational Gradient filter that removes the circularly symmetric glowing halo around the nucleus of 3I/ATLAS. Applying this filter to 6 images of 3I/ATLAS taken by the Hubble Space Telescope on January 14, 2026 (available here), revealed a symmetric system of 3 mini-jets out to 25,000 kilometers. The 3 mini-jets are separated by 120 degrees from each other in sky projection, and are supplemented by a 4th anti-tail jet extending 10 times farther in the sunward direction. The 3 symmetric jets appear persistently in the Larson-Sekanina filtering of 24 other images taken by the Hubble Space Telescopes on November 30, December 4, 12, 27, 2025 and January 7, 14, 2026 (as listed here). Analysis of these images was presented in a new paper that I co-authored with Toni Scarmato , which was posted today here. It demonstrates that the jet structure around 3I/ATLAS wobbles periodically by +/-20 degrees over a period of 7.1 hours. The wobble is likely the result of rotation, with each jet behaving like a misaligned beam from a rotating lighthouse. The rotation axis is oriented surprisingly close (within 10–20 degrees) to the sunward direction, as already inferred back in August 2025 (and reported here). In another paper that I co-authored with Mauro Barbieri last week (available here), we had shown that on January 22, 2026, the observing direction of 3I/ATLAS from Earth will align to within 0.69 degrees with the anti-sunward direction. During that rare alignment, the rotating configuration of 3 mini-jets might trace a circle in the sky. My brilliant colleague, Dr. Frank Laukien, noted: “The symmetric 120-degrees angular spacing between the 3 mini-jets is astounding! It is hard to imagine such a symmetry in a natural macroscopic object. A key question is: are three symmetric mini-jets the minimum viable configuration of propulsion devices to re-orient an object in three-dimensional space? Human-made satellite thrusters usually come in pairs on opposing directions. Could the mini-jet geometric arrangement be an indication of active technology? For orthogonal thruster systems, one would need 6 thrusters, with two opposing thrusters along each of the three orthogonal spatial directions. If 3I/ATLAS rotates around its major axis every 7.1 hours or so, then thrusters in the direction of the major axis would not be very useful, and perhaps just (3+1)=4 thrusters in the plane orthogonal to the major rotation axis are sufficient for some sort of technical manipulation like attitude adjustments?” Indeed, we observe a system of 3 symmetric mini-jets plus 1 major jet. Additional data might help to address Frank’s question. The symmetric jet structure is just one out of 18 anomalies of 3I/ATLAS, as listed here. Identifying one of them as a clear technological signature would boost the rank of 3I/ATLAS high on the Loeb Classification Scale, formulated here, here and here. Scientific work requires patience, since new knowledge comes one day at a time. Life brings joy when each day teaches us something new. My morning jog at sunrise today was decorated by symmetric fresh snowflakes. There is nothing more invigorating than the beauty of symmetry in nature, both on Earth and in the sky. A snow-decorated tree along a jogging path at sunrise. (Image credit: Avi Loeb, January 19, 2026)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: Troy Dawson)Today, THE SUNDAY TIMES reported here that a former analyst of the UK central bank, Helen McCaw, urges the Bank of England to plan for a financial crisis that might be triggered by an official announcement confirming the existence of alien intelligence. Such an announcement could destabilize the financial markets and cause civil unrest. McCaw, who worked for the Bank of England for a decade starting in 2002, insists that politicians and bankers can no longer afford to ignore alien intelligence. She emailed me a few months after I started studying the interstellar object 3I/ATLAS, and included a copy of a comprehensive paper she wrote, which was partly posted here. Her email was triggered by a White Paper that I submitted to the United Nations about the potential risk from interstellar objects that carry alien technologies (posted here and here, with co-authors Omer Eldadi and Gershon Tenebaum). The risk assessment can be based on the Loeb Classification Scale, as formulated here, here and here. As soon as the interstellar object 3I/ATLAS was discovered to follow a trajectory which is nearly aligned with the orbital plane of the planets around the Sun, I urged policymakers to make contingency plans for a “black swan event”. Even if the a priori probability of 3I/ATLAS being an alien spacecraft is small, the societal implications from it carrying technology could be huge. It therefore makes sense to collect as much data as possible about it in order to assess the potential risk from anomalies that deviate from the familiar characteristics of natural comets. Ignoring such risk is common among scientists who focus on the most-likely scenario to protect their reputation, but is unwise for policymakers who worry about the devastating implications of low-probability catastrophes to society. On December 31, 2025, the Central Intelligence Agency (CIA) replied to a Freedom of Information Act (FOIA) inquiry by John Greenewald Jr., with the statement that it can “neither deny nor confirm the existence or nonexistence of records” related to 3I/ATLAS (as posted here). Why would the CIA treat 3I/ATLAS as a sensitive matter? The simplest interpretation is that some government officials wished to make sure that 3I/ATLAS is not a black swan event. It makes sense to hide related records from public view in order to avoid panic, societal unrest or instability of financial markets. Such discussions were not limited to the US. Russian president Vladimir Putin was asked by a reporter about 3I/ATLAS during his annual televised news conference on December 19, 2025, accessible here, . Here is the transcript of this public exchange: “Journalist: I have a question about the unusual object 3I/ATLAS which is currently approaching us. If the predictions are to be believed today, December 19th, either a spacecraft with an engine or just a comet will approach Earth. My question is this, what do intelligence services report to you? Are there really signs of artificial origin? As funny as it may sound, there are indeed many theories and speculations. We, at Tyumen — the oil capital of Russia, are ready to welcome any guests but if they are from space we would like to prepare. Secondly is the date of our meeting today related to this forecast since it’s the first time that we are summing up the year on a Friday. Putin: Is your name Christina? I’ll tell you, but it must remain exclusively between us. This is classified information. It’s our secret weapon, but we will only use it in the most extreme case because we are against deploying weapons in space. Seriously though, it’s a comet. Our scientists are aware of what is happening. Moreover, this is a comet from another place, so it behaves differently from comets of our galactic origin. It has a different shell and as it approaches closer to the Sun, slightly different processes occur on its surface, including in the field tail of this rocket. Things look different there, but it’s quite large. I think somewhere between 2 to 6 kilometers. Look, the moon is 400,000 kilometers away from us. And the object you are talking about is hundreds of millions of kilometers away. I don’t think it poses any threat to us. We’ll let it go to Jupiter. And at the beginning of next year, the comet will leave the Solar system.” For now, the official statement is that 3I/ATLAS is a natural comet. But those of us who continue monitoring 3I/ATLAS, are noticing new anomalies, including a weird geometry of three symmetric jets around its nucleus — as revealed by new images from the Hubble Space Telescope on January 14, 2026. False-color brightness map of the projected jet structure around 3I/ATLAS, imaged on January 14, 2026 by the Hubble Space Telescope and processed through a Larson-Sekanina Rotational Gradient filter, which removes the circularly symmetric glow around the nucleus. The jet system includes a prominent anti-tail, directed at the Sun towards the lower left, along with a system of three mini-jets which are equally separated by an angle of 120 degrees from each other. (Image credit: Toni Scarmato, based on data released by NASA/ESA/STScI here)*** The time is therefore ripe to update the list of anomalies of 3I/ATLAS. Some of these oddities are likely to have a natural explanation but others make 3I/ATLAS surprisingly rare among the known population of natural comets. Once the NSF-DOE Rubin will discover dozens of new interstellar objects over the coming decade, we will be able to understand just how unlikely 1I/`Oumuamua and 3I/ATLAS were. This is for the same reason that having many blind dates allows a dater to realize how exceptional is any one of these dating partners. At the very least, the anomalies listed below should intrigue astronomers to study them further: Geometric Coincidences: 1. The retrograde trajectory of 3I/ATLAS is aligned to within 5 degrees with the orbital plane of the planets around the Sun, with a probability of 0.2% (as discussed here). The Milky-Way disk is misaligned with the ecliptic plane by about 60 degrees. This suggests that the trajectory of 3I/ATLAS may have been planned. 2. The arrival time of 3I/ATLAS was fine-tuned to bring it to minimum distances of 29 and 54 million kilometers from Mars and Jupiter, respectively, and be unobservable from Earth at perihelion (as discussed here). 3. The forecasted perijove distance of 3I/ATLAS during its encounter with Jupiter on March 16, 2026 is 53.6 million kilometers, is very close to Jupiter’s Hill radius, 53.5 million kilometers (as discussed here). The rare coincidence might mean that 3I/ATLAS intends to release technological devices as satellites near Jupiter’s Lagrange points — where fuel requirements are minimal. 4. Analysis of the Hubble Space Telescope image of 3I/ATLAS from July 21, 2025 (as discussed here) suggests that the anti-tail before perihelion must have been in the form of a collimated jet towards the Sun that is about ten times longer than it is wide. This is similar to the collimation observed in post-perihelion images out to several hundred thousand kilometers. No known comet exhibited a physical sunward jet of this length that is not a perspective effect. For a technological object, a beam of particles might be used to block the solar wind from impacting the nucleus surface at a relative speed of order 500 kilometers per second. In addition, the veil of dust around 3I/ATLAS is just of the right column needed to block sunlight from hitting the nucleus surface (as discussed here). 5. At large distances, the initial rotation axis of 3I/ATLAS was aligned to within 8 degrees with the sunward direction when it entered the solar system (as reported here). The probability for that is 0.5%. 6. The observed wobble of the pre-perihelion jet in the direction of the Sun (as reported here during July and August 2025) requires the base of the jet to be within 8 degrees from the sun-facing pole, with probability of 0.5%. 7. The existence of a prominent jet towards the Sun on the way of 3I/ATLAS out of the solar system requires a similar coincidence near the opposite pole of the rotation axis. The fact that a collimated jet appears as the sunward anti-tail both before and after perihelion (while reversing direction at perihelion relative to the direction of motion), has a tiny probability of occurring at random, equal to the square of 0.5% or 0.000025. 8. Processing of the Hubble Space Telescope Images from January 14, 2026 by the Larson-Sekanina filter — which removes the circularly-symmetric glow round the nucleus, reveals a system of three mini-jets which are symmetrically separated by 120 degrees from each other (as discussed here). 9. The launch base of the post-perihelion anti-tail jet resided on the nightside of 3I/ATLAS before perihelion and the base of the pre-perihelion anti-tail jet is now on the nightside of 3I/ATLAS after perihelion. For these bases to be active only when facing the Sun, they must be well insulated on the nightside for a period longer than several months. Heat naturally flows by conduction throughout the body of a natural comet, making this insulation requirement difficult to satisfy. 10. The gravitational deflection of 3I/ATLAS by 16 degrees at perihelion (as discussed here), is exactly twice the opening angle of the anti-tail before perihelion. This coincidence allows the wobbling jet around the rotation axis to generate an anti-tail in the direction of the Sun before perihelion and a counter jet on the opposite pole after perihelion, with a jet opening angle of 8 degrees on both poles. 11. On January 22, 2026, 3I/ATLAS will align with the Sun-Earth axis to within an extraordinarily small angle of 0.69 degrees (as discussed here). At that time its anti-tail will be pointing at Earth. 12. 3I/ATLAS arrived from a direction coincident with the radio “Wow! Signal” to within 9 degrees, with a probability of 0.6% (as discussed here). Composition Anomalies of the Gas Shed by 3I/ATLAS: 13. 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 (as reported here). This might indicate a technological origin for these abundances. 14. The anti-tail is capable of penetrating hundreds of thousands of kilometers through the solar wind and the solar radiation. In order not to be stopped, the dust particles must be much larger than common sub-micron particles of interstellar dust (as discussed here). However, if the particles are bigger than a millimeter, then they must carry an untenable amount of mass in order to account for 99% of the scattered sunlight around 3I/ATLAS, as observed in the Hubble images. 15. Data from the SPHEREx space observatory indicated the existence of icy fragments around 3I/ATLAS before perihelion (as reported here in August 2025). However, the spectral signature of ice disappeared in the SPHEREx data after perihelion, taken during December 2025 (as reported here), when abundant organic molecules in gas phase, such as CH3OH, H2CO, CH4, and C2H6, were discovered, along with an enhancement by a factor of ~20 in the water production rate. To survive cosmic-ray bombardment along an interstellar journey that lasted billions of years, these organic molecules must have been buried under a thick layer of material, at least 10-meters in depth. Unusual Physical Properties: 16. The nucleus of 3I/ATLAS is more massive than 1I/`Oumuamua and 2I/Borisov, while moving faster than both (as discussed here and here). This suggests that 3I/ATLAS might have targeted the inner solar system rather than being drawn at random from the reservoir of interstellar icebergs. 17. 3I/ATLAS shows extreme negative polarization, unprecedented for all known comets, including 2I/Borisov (as discussed here and here). This unusual polarization may be related to its unusual anti-tail. 18. Near perihelion, 3I/ATLAS brightened faster than any known comet and was bluer than the Sun (as discussed here). To paraphrase Oscar Wilde: “We are all in the gutter, but some of us are looking at 3I/ATLAS.” *** Deriving new knowledge out of curiosity is a trait shared by genuine scientists and artists. This was reiterated in an email I had received before my morning jog at sunrise through snowy frozen roads near Boston, Massachusetts. The message came from a completely world down-under, where summertime prevails right now: “Hi Professor Loeb, I have been absolutely engrossed in 3I/ATLAS and just wanted to say THANKYOU….I love your work, you are an inspiration and you have influenced me as a musician to create a 3I/ATLAS song….I played around with many song concepts, lyrics, rhythms etc. to land on a tune now assisted by AI (I feel that is very appropriate) that I wished to share, and perhaps you will like it put some nice CANS on and enjoy professor….This song will be released next week on Spotify….I wanted you to hear it prior to release. Take care and Thankyou again for your scientific contribution to our never-ending quest for understanding of all things universal. Ohhhh nearly forgot — 3I/ATLAS in my mind, given the research of highlighted anomalies, is 100% (should be higher on the Loeb scale!) Alien. Take care Troy Dawson Brisbane Australia” 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

False-color brightness map of 3I/ATLAS on January 14, 2026 in six 170 second exposures by the WFC3 UVIS (F350LP) camera of the Hubble Space Telescope (top image, spanning 130,000 kilometers on a side). The map was processed through a Larson-Sekanina Rotational Gradient filter, which removes the circularly symmetric glow around the nucleus (bottom image), showing four jets. The jet structure includes a prominent anti-tail, directed at the Sun towards the lower left, along with a system of three mini-jets. These mini-jets are equally separated by an angle of 120 degrees from each other, but none of them is pointing away from the Sun as expected for a standard cometary tail. (Image credit: Toni Scarmato, based on data released by NASA/ESA/STScI here)A new set of six images, taken by the Hubble Space Telescope on January 14, 2026, show the brightness map of the glowing halo surrounding 3I/ATLAS after perihelion. The glow extends beyond 130,000 kilometers towards the Sun, about a third of the Earth-Moon separation. When the image is processed through the Larson-Sekanina Rotational Gradient filter which removes the circularly symmetric glow around the nucleus, it features a weird configuration of jets, including a prominent anti-tail outflow directed towards the Sun, supplemented by a system of three mini-jets. These mini-jets are equally separated by an angle of 120 degrees from each other, and none of them is pointing away from the Sun as expected for a standard cometary tail. The last Hubble exposure ends half an hour after the first exposure starts. A new paper that I co-authored with Toni Scarmato (accessible here) analyzed previous Hubble images from December 2025 and concluded that the jet structure wobbles periodically by +/-20 degrees over a period of 7.1 hours. This implies a modest shift by 5.6 degrees over 0.5 hours in the orientation of the jet system on January 14, 2026. On January 22, 2026, the Earth will be aligned to within 0.69 degrees with the line connecting 3I/ATLAS to the Sun (as reported in the new paper I co-authored with Mauro Barbieri here). Just as in the context of a full Moon, this rare alignment will allow us to see 3I/ATLAS and the glowing dust around it in full brightness when the area of their reflecting surfaces will be maximized. Since we will be observing 3I/ATLAS from the direction of the Sun on that date, its sunward anti-tail will be pointed at us. Measurements of the brightness surge and polarization of 3I/ATLAS at opposition to the Sun could shed new light on the composition and size of the fragments it launches into the anti-tail. What is the nature of the anti-tail that allows it to penetrate hundreds of thousands of kilometers through the Solar wind and radiation without being deflected away from the Sun, as often the case in familiar cometary tails? Is the anti-tail composed of fragments of ice (as suggested in a paper I co-authored with Eric Keto, published here), large dust grains (as I suggested in a research note, posted here), or massive objects (as I suggested in a paper, published here)? Data from the SPHEREx space observatory indicated the existence of icy fragments around 3I/ATLAS before perihelion (as reported here in August 2025). However, the spectral signature of ice disappeared in the SPHEREx data after perihelion, taken during December 2025 (as reported here), when abundant organic molecules in gas phase, such as CH3OH, H2CO, CH4, and C2H6, were discovered, along with an enhancement by a factor of ~20 in the water production rate. To survive cosmic-ray bombardment along an interstellar journey that lasted billions of years, these organic molecules must have been buried under a thick layer of material, at least 10-meters in depth. 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