Astronomy and Stars
Discussions about astronomy and stars. As we look further out what can we find in the universe beyond Earth's atmosphere?
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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 follo…
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(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 read…
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An artist’s illustration of the Solar System, calibrated by the scale of the Earth-Sun separation (1 AU). The outer edge of objects bound to the Sun in the so-called Oort Cloud is estimated to be at a distance of about 100,000 AU. Voyager 1, humanity’s most distant spacecraft, is at a distance of about 172 AU, equivalent to 26 billion kilometers or nearly a light day away. (Image credit: NASA/JPL)The latest data from the Hubble Space Telescope (reported here) implies that the radius of the nucleus of the interstellar object 3I/ATLAS is 1.3 kilometers. In what follows, I will assume — as most astronomer do — that 3I/ATLAS is a natural comet drawn at random from a parent po…
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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 create…
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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 amb…
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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 …
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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 o…
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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 nucle…
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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:/…
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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 purp…
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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…
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Nature is more imaginative than we are, and so experimental data is crucial for gaining new knowledge about the Universe. This photograph of ALICE (A Large Ion Collider Experiment) shows one of the nine detectors at CERN’s Large Hadron Collider. The experiment is designed to study the properties of the quark-gluon plasma that filled the Universe during the first 10 millionths of a second after the Big Bang, when the temperature of the cosmic soup of elementary particles was above 2 trillion degrees Kelvin. (Image credit: CERN/Julien Ordan/Science Source).Wonderful news! I have just launched my official YouTube channel at the link: https://www.youtube.com/@ProfessorAviLoeb…
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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 telesco…
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In 2024, Sandia National Laboratories received a brain-based computing system called Hala Point from Intel Corporation, that has 1.15 billion artificial neurons aiming to advance large-scale brain-inspired computing. The image shows a three-dimensional rendering of the motherboard with an illuminated AI chipset used by this neuromorphic computer. (Image credit: Sandia National Laboratory)At the end of a late-night interview yesterday with the brilliant Nate Cain at The Raising Cain Show podcast (accessible here), I was asked whether humans have a soul, given their sense of free will, consciousness and “out of body” experiences? By a soul, Nate referred to an ingredient th…
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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 …
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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 hidde…
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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 geomet…
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Television interview of Avi Loeb by CBS. (Image Credit: Loeb’s photo collection)The saga to preserve my scientific integrity against deception by artificial intelligence (AI) started two months ago and was described during that period by a Futurism news article here, an essay I posted here, and an interview with Gadi Schwartz on NBC News here. Throughout this period, I received thousands of emails from fans who alerted me to YouTube channels displaying fake AI-generated videos of me speaking about science. Many of my fans identified the deception because the hands of the clock behind me did not move and because some statements in the videos contradicted what I wrote in my…
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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-wat…
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(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 tel…
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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 …
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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 rel…
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(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 …
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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.…
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Top panel: 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 300,00 kilometers on a side. The brightness contours represent 5, 20 and 50 times the background noise; color bars are in mega-Jansky per steradian. The celestial North-and-East directions are shown by black arrows, along with the anti-velocity (dashed-blue) and anti-sun (solid-red) directions. On these large scales, 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. Middle panel: Flux spectrophotometry (po…
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Illustration of the anti-sunward jet and the opposing anti-tail in the Larson-Sekanina Rotational Gradient filter of a representative image from the Hubble Space Telescope during the month of December 2026. The position angle (PA) of the anti-sunward jet is marked using the standard convention N=0 degrees and E=90 degrees. (Image credit: T. Scarmato and A. Loeb 2026, full paper accessible here)How fast does the interstellar object 3I/ATLAS rotate now? Did its rotation period change during perihelion, when it came closest to the Sun on October 29, 2025? There are two ways to measure the rotation period of 3I/ATLAS. One uses the periodic shift in the orientation of the jet …
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The angle between the Sun-Earth axis and the Sun-3I/Atlas axis in degrees, as a function of date. (Credit: M. Barbieri and A. Loeb; full paper accessible here)In a new research note that I co-authored with Mauro Barbieri, we point out that on 22 January 2026, the interstellar object 3I/ATLAS will align to within an exceptionally small angle of 0.69 degrees, with the Earth-Sun axis. This rare alignment provides unique circumstances for measuring a novel effect called `the opposition surge’ for the dust shed by 3I/ATLAS. We characterize the alignment geometry, outline key scientific opportunities, and provide observational requirements for data collection. Observations befo…
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The Near Transits of the Inner Planets Across the Face of the Sun from the Vantage Point of 3I/ATLASThe expected trajectory of 3I/ATLAS will nearly align with a transit of the Earth across the face of the Sun on January 22, 2026. (Image credit: NASA/JPL Horizons)When a planet transits in front of the disk of its host star, its blocks some of the starlight and reduces slightly the brightness of the star. The tiny fraction of starlight passing through the atmosphere of the planet allows to measure the atmospheric composition. In particular, the transit of the Earth in front of the Sun produces a dimming of only 0.008 percent for a distant observer that is aligned with the S…
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Image of 3I/ATLAS, taken on January 7th, 2026 by the Hubble Space Telescope (top panel), and processed through the Larson-Sekanina rotational gradient filter (bottom panel). The bottom panel shows a triple jet structure with a prominent anti-tail jet in the direction of the Sun, towards the lower left corner of the image. The anti-tail extends to a scale of order the Earth-Moon separation. (Image credit: Toni Scarmato, based on data released by NASA/ESA/STScI here)When the interstellar object 3I/ATLAS was first imaged by the Hubble Space Telescope on July 21st, 2025, it became evident that the glowing halo of light around it extends by an extra factor of ~2 towards the Su…
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Expected trajectory of 3I/ATLAS, as of January 7, 2025. (Image credit: NASA/JPL Horizons)About 8,000 years after entering the Oort Cloud of the solar system at a distance of 100,000 times the Earth-Sun separation, the interstellar object 3I/ATLAS embarks on the second half of its trip, now away from the Sun and towards Jupiter. According to its forecasted gravitational trajectory and including its non-gravitational acceleration, 3I/ATLAS is expected to arrive on March 17, 2026 to within 30.46 million kilometers from Jupiter’s irregular moon Eupheme. A day earlier, 3I/ATLAS will be within 53.61 million kilometers from Jupiter, surprisingly close to Jupiter’s Hill radius of…
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If 3I/ATLAS is a Comet, Why Would the CIA “Neither Deny, Nor Confirm” the Existence of Records on It?An image of 3I/ATLAS at 3:34 UTC on December 30, 2025 from nine 120-second exposures, taken with the Virtual Telescope Project facility in Manciano, Italy. A prominent anti-tail jet is clearly observed in the direction of the Sun, towards the lower left. (Image credit: Virtual Telescope)So far, 3I/ATLAS displayed a number of unexplained features relative to familiar comets — as I listed here. One could have hoped that these puzzles would trigger a healthy scientific debate about the nature of 3I/ATLAS. Instead, the case was officially closed by NASA officials without any d…
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Stones from the Western Wall of the Second Temple in Jerusalem, knocked onto the street below by Roman battering rams on the 9th of Av, 70 C.E. This first century street is located at the base of the Temple Mount at the corner where the Western and Southern walls of the Temple met. (Image credit: Avi Loeb, January 2, 2025)Last week, I visited with my family the Old City of Jerusalem, which was constructed at ancient times by our civilization. This was a timely history lesson for me, given that my attention over the past six months was dedicated to the possibility that the interstellar object 3I/ATLAS might have been constructed by another civilization. What struck me in p…
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Albert Einstein at age 14 in 1893. How many 14-year-old Einstein-level young adults have ever lived? (Image credit: Wikipedia)Today there are over 8 billion people alive but a century ago there were only 2 billion people alive. Given a probability distribution of innate human intelligence with a sharply declining tail at high values, one would expect there to be four times more Einstein-level scientists today than a century ago. In fact, there should be scientists even more talented than Albert Einstein because the tail of the distribution should be sampled to higher intelligence levels within a larger population. This is not the impression one gets when gauging in a hist…
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Images of the jet structure of 3I/ATLAS from the Hubble Space Telescope, processed through the Larson-Sekanina rotation gradient filter, show a variable jet structure. The top panels zoom in on the inner jets within 24,000 kilometers from 3I/ATLAS on November 30, 2025 (top left), and December 27, 2025 (top right). Zooming out to the outer structure extending out to 100,000 kilometers, shown in the lower two panels for December 12 (bottom left) and December 27 (bottom right) is dominated by the anti-tail jet, directed at the Sun towards the lower left corner of the image. (Image credit: Toni Scarmato, based on data released by NASA/ESA/STScI here)Seventeen images of the in…
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If 3I/ATLAS is a Comet, then Its Anti-Tail Jet Should Not Include Streaming Gas Beyond ~5,000 kilometersFalse-color image of 3I/ATLAS (top panel), taken on December 27, 2025 by a 0.2-meter telescope in Belgium. The field of view is 14.4 by 23.3 arcminutes, corresponding to 1.1 by 1.8 million kilometers. Another image from the same telescope on December 19, 2025 which was processed through the Larson-Sekanina rotational gradient filter (bottom panel), shows a prominent anti-tail jet towards the Sun, as indicated by the yellow line in the inset. (Image credit: Alfons Diepvens)During the past two months after perihelion, the anti-tail jet from the interstellar object 3I/ATLA…
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False-color image of 3I/ATLAS on December 12, 2025 taken by the WFC3 UVIS (F350LP) instrument of the Hubble Space Telescope (top panel), and processed with the Larson-Sekanina gradient filter (bottom panel). The prominent jet is an anti-tail directed at the Sun towards the lower left corner. (Image credit: NASA/ESA/STScI; filter processing: Toni Scarmato)As we summarize 2025 and approach a New Year, the time is ripe to recognize the most significant dating partner that humanity had in 2025: the interstellar object 3I/ATLAS. Given that it is only our third blind date from interstellar space, we tend to consider the encounter as unique and our dating partner as having excep…
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Images of 3I/ATLAS through 170 second exposures by the WFC3 UVIS (F350LP) camera of the Hubble Space Telescope, processed through the Larson-Sekanina rotation gradient filter, show a double jet structure. The left panel displays the data on December 12, 2025, and the right panel on December 27, 2025. The relative brightness of the two jets changes between these jets, either due to jet rotational wobble or source variability. The brightness is dominated by the anti-tail jet, directed at the Sun towards the lower left side. (Image credit: Toni Scarmato, based on data released by NASA/ESA/STScI here)New images of the interstellar object 3I/ATLAS, taken through 170 second exp…
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Image of 3I/ATLAS on Dec. 21.627, 2025 UTC (with a contour plot on the left). The jet to the right (west) is the anti-tail heading towards the Sun. The field is 6 by 12 arcminutes, and the exposure duration is 15 seconds on the NEOSSat 0.15-m Maksutov orbiting telescope. The coordinate grid is ecliptic 2000. (Image credit: D. D. Balam (DAO/NRC), C. E. Spratt (ret), D. W. E. Green (CBAT), P. Langill (RAO/U. of Calgary), Omar Elmi (CSA), Jack Williams (CSA) & Canadian Space Agency)In my latest two essays, accessible here and here, I showed that the characteristic radius of dust particles in the anti-tail jet launched from the interstellar object 3I/ATLAS is of order ~10…
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Images of the interstellar object 3I/ATLAS from the Two-Meter Twin Telescope (TTT) and the Transient Survey Telescope (TST) located at Tenerife, Spain (right panels), and the corresponding Laplacian-filtered images (left panels). The observation date, start and end times (UTC), number of sidereal-tracking exposures, and total integration time are indicated above each panel. The projected velocity vector of 3I/ATLAS (red arrow) and the anti-solar direction (yellow arrow) are shown, along with the image scale and orientation. Red cross marks the brightness peak. The direction of the anti-tail and tail are marked by thin red and yellow lines, respectively. Brightness contour…
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Images of the tightly-collimated anti-tail jet from 3I/ATLAS in the sunward direction (lower left), as processed through a Larson-Sekanina gradient filter on December 15, 2025 (top) by Toni Scarmato, and on December 13, 2025 (bottom) by Teerasak Thaluang.Recent images of the interstellar object 3I/ATLAS show a tightly collimated anti-tail jet that extends out to at least 100,000 kilometers in length towards the Sun. It is commonly assumed that the glow in this jet results from the scattering of sunlight by dust particles. Here we derive constraints on the characteristic size of these particles, assuming that they originate from a natural comet. If these particles start wi…
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Data from radio observations of 3I/ATLAS by the Allen Telescope Array on July 2, 2025, showing a signal in both the on-beam and the off-beam panels, indicating a local interferer in the allocation allotted to fixed-satellite service (Earth-to-space). (Image credit: S. Sheikh et al. 2025)A new paper, posted here, reports data from 7.25 hours during July 2, 2025 of radio observations of the interstellar object 3I/ATLAS with the Allen Telescope Array. Within the frequency range of 1–9 GHz, there were nearly 74 million narrowband hits. After mitigating Radio Frequency Interference in the dataset, only about 2 million hits were left. These hits were further filtered by sky loc…
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(Image credit: PUCHAN/ISTOCKPHOTO)On December 19, 2025, the interstellar object 3I/ATLAS came closest to Earth at a distance of 269 million kilometers. As many of us anticipate holiday gifts from our family members in the coming weeks, some wonder whether 3I/ATLAS might deliver us an interstellar gift of sorts. In other words: Will any of the material shed by 3I/ATLAS arrive on Earth? One concern stems from the fact that the gas plume around 3I/ATLAS is known to contain cyanide (as reported here) and hydrogen cyanide (as reported here) — a poisonous gas which was used as a chemical weapon during World War I. Gladly, this risk is mitigated by the solar wind. Given the mass…
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(Image Credit: Naeblys/Istock/Getty Images)The Loeb scale ranks interstellar objects on a scale between 0 for natural icy rocks (comets or asteroids) to 10 for alien technology that is a potential threat to humanity. The Loeb classification was quantified in two peer-reviewed publications, available here and here. This quantitative classification was expanded a week ago in a new paper here to a formalism that evolves the ranking of an interstellar object as new data about it comes in. Shortly after 3I/ATLAS was discovered in July 2025, I ranked is as 4 on the Loeb Scale. When asked to update the rank recently, I declined to do so until new data from the period bracketing …
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Analysis of the image of 3I/ATLAS at its closest approach to Earth on December 19, 2025. The top row shows the brightness maps in different wavelength bands (R-centered on 0.659, G-centered on 0.530 and Blu-centered on 0.445 micrometers). The bottom row shows the brightness map from the Larson-Sekanina gradient filter, featuring a prominent anti-tail jet in the sunward direction, towards the lower left. The appearance resembles a rocket receding way from the Sun. (Image credit: Toni Scarmato)The Voyager Golden Records, containing a time capsule of sounds, images, music and messages from Earth, were attached to NASA’s Voyager 1 and 2 spacecraft which are currently travelin…
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An image of 3I/ATLAS at its closest approach to Earth on December 19, 2025, featuring a prominent anti-tail jet in the sunward direction, towards the lower left. (Image credit: Dr. Sebastian Voltimer)Humans are interesting cosmic creatures. More than four centuries ago, we were convinced that the Universe centers on us. Recently, we realized that there are about ten billion houses like ours on the cosmic street of the Milky-Way and most of them formed billions of years before the Earth-Sun system. However, our popular view is that visitors from these houses might show up in our cosmic neighborhood because of their interest in our home. Well, guess what: if you are late to…
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A composite image of the interstellar object 3I/ATLAS, captured on November 6, 2025 by the Europa Ultraviolet Spectrograph instrument (UVS) on NASA’s Europa Clipper spacecraft, from a distance of 164 million kilometers. (Image credit: NASA/JPL-Caltech/SWRI)NASA’s Europa Clipper spacecraft observed the interstellar object 3I/ATLAS on November 6, 2025, from a distance of 164 million kilometers. During an observing period of seven hours, the Europa Ultraviolet Spectrograph (UVS) instrument recorded data on the abundances of various elements in the gas plume surrounding the nucleus of 3I/ATLAS. A false-color image was obtained by stacking the brightness maps at multiple UV wa…
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Image of the interstellar object 3I/ATLAS (top left panel) from a 0.25-meter telescope in Calabria, Italy, taken on December 15, 2025 at 1:58 UTC with 1.38 arcseconds per pixel — corresponding to 3,850 kilometers at the source distance. The other three panels show a brightness map at different wavelength bands centered on 0.658 [R], 0.53 (Green) and 0.445 (Blue) micrometers, using a Larson-Sekanina gradient filter. Their field of view spans 1.6 by 0.7 million kilometers and shows a prominent tightly-collimated anti-tail jet from 3I/ATLAS in the sunward direction, towards the bottom left corner. (Image credit: Toni Scarmato)My latest essay, available here, listed 15 anomal…
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Image of the interstellar object 3I/ATLAS (top left panel) from a 0.25-meter telescope in Calabria, Italy, taken on December 15, 2025 at 1:58 UTC with 1.38 arcseconds per pixel — corresponding to 3,850 kilometers at the source distance. The other three panels show a brightness map at different wavelength bands centered on 0.658 [R], 0.53 (Green) and 0.445 (Blue) micrometers, using a Larson-Sekanina gradient filter. Their field of view spans 1.6 by 0.7 million kilometers and shows a prominent tightly-collimated anti-tail jet from 3I/ATLAS in the sunward direction, towards the bottom left corner. (Image credit: Toni Scarmato)The near alignment of the rotation axis of the in…
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Images of the tightly-collimated anti-tail jet from 3I/Atlas in the sunward direction (lower left), as processed through a Larson-Sekanina gradient filter on December 15 (top) and 9 (middle), 2025 by Toni Scarmato, and on December 13, 2025 (bottom) by Teerasak Thaluang.My latest essay on the 14th anomaly of the interstellar object 3I/ATLAS (available here) focused on the alignment of its rotation axis with the sunward direction at large distances. The fact that a tightly collimated jet appears as the anti-tail in the direction of the Sun both before and after perihelion has a tiny probability of occurring at random, 0.000025. But the collimation of the jet to within 8 deg…
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A 14th Anomaly of 3I/ATLAS: Alignment of Its Rotation Axis with the Sunward Direction at Large DistancesPhase angle of the position angle of the anti-tail of 3I/ATLAS, measured at a projected distance of 6,000 kilometers from the brightness peak and phased with the calculated 7.74 (± 0.35) hour period. The horizontal red line is the mean value of position angles, representing the sky-projected orientation of the rotation axis. (Image credit: Serra-Ricart, Licandro & Alarcon 2025)The new paper (accessible here) reporting the detection of a periodic wobble in the anti-tail jet of the interstellar object 3I/ATLAS during July and August, 2025, implies that the jet base is…
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