A 28-Hour Movie of 3I/ATLAS from TESS
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.
In 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 transmits a technological signal or releases 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
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.
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