Q&A About 3I/ATLAS, a Week Before Its Closest Approach to Jupiter
After a four-hour interview with AJ Gentile in Las Vegas yesterday, I returned to Boston at midnight and before my morning jog — I answered the following set of questions from a journalist about the interstellar object 3I/ATLAS:
- You previously estimated the likelihood that 3I/ATLAS is the creation of an alien civilization. A large body of observational data has now been accumulated. Has this probability increased or decreased?
When 3I/ATLAS was discovered in July 2025, I gave it a rank of 4 on the Loeb Classification scale of interstellar objects (defined here), where 0 means a natural comet and 10 means alien technology that poses a major threat to humanity. 3I/ATLAS displayed rare geometric anomalies. Its trajectory was leading towards the inner solar system, within 5 degrees of the orbital plane of the planets around the Sun, and with a rotation axis that is nearly aligned with the direction of the Sun. It also featured a prominent anti-tail in the direction of the Sun rather than a commonly observed cometary tail of dust and gas pushed away by the solar radiation and wind. Before perihelion, the plume of gas around 3I/ATLAS featured nickel with much less iron as found in industrially produced nickel alloys, and after perihelion it featured methane (CH4), a biosignature whose volatility lies between carbon dioxide (CO2) and carbon monoxide (CO) — both of which well detected well before methane. Forty post-perihelion images obtained by the Hubble space telescope, showed a circular glow of reflected sunlight plus a symmetric system of three jets, equally separated from each other around the nucleus (as summarized here). Are these technological thrusters or merely a position coincidence of three random pockets of ice on the surface of a rocky iceberg?
Given all that we have learned so far (summarized as 18 anomalies listed here), and assuming that nothing unusual will happen near Jupiter, I would reduce the rank of 3I/ATLAS now to 3 on the Loeb Scale, because its natural cometary behavior is accompanied by multiple unexplained anomalies. In that case, 3I/ATLAS could also be a Trojan Horse, namely a hitchhiked interstellar iceberg on a selected path through the solar system — on which technological equipment was installed by an extraterrestrial civilization.
- Did you notice that 3I/ATLAS came from the same region of the sky where a strange radio signal was received in 1977? What was this signal? An attempt to warn of its approach? A simple technical transmission?
Yes, I was first to point out this coincidence of 9 degrees alignment between the arrival direction of 3I/ATLAS and the “Wow! Radio Signal” detected in 1977, in an essay I posted here. This chance alignment has a random probability of less than a percent. Attempts to detect radio transmission from 3I/ATLAS towards Earth on a few specific days during the past six months failed. We do not know what the “Wow! Signal” means; it could have been transmission from a companion gadget to 3I/ATLAS or from its senders. This coincidence represents one additional rare anomaly about 3I/ATLAS.
- Are there any signs that 3I/ATLAS left “observers” near Earth or will do so near Jupiter?
3I/ATLAS will arrive at closest distance of 53.6 million kilometers from Jupiter on March 16, 2026. Coincidentally, this distance is close to the so-called `Hill radius’, where Jupiter’s gravity dominated over the Sun’s tidal gravity (as I pointed out here), allowing for the deployment of probes in a gravitationally bound orbits around Jupiter as long as they receive an appropriate kick that will cancel the fast velocity of 3I/ATLAS at 66 kilometers per second relative to Jupiter. So far, we had not seen evidence for the release of such objects but it would make sense to check with future imaging data obtained by the Juno, Juice and Europa Clipper spacecraft around Jupiter, whether new small satellites were added around Jupiter. So far, we have not noticed any related objects near Earth.
- Since 3I/ATLAS was an active source of organic matter, could it have “infected” the Solar System with its own kind of life? In that case, all we can do is wait for the “new” life to displace our “old” one and simply return as if it were its own.
After perihelion, 3I/ATLAS released organic molecules which are biomarkers, as I discussed here. Is this a sign that 3I/ATLAS carries life? For a civilization that has the ambition of becoming an interstellar gardener, it would make sense to deposit microbes inside a natural iceberg that has the nutrients needed for life, so that when the iceberg gets close to a star like the Sun it would shed these seeds on a potentially fertile ground like Earth. Our civilization could follow this vision by depositing a capsule with microbes, warmed by a power source, on a future interstellar iceberg, at a cost that matches the budgets of our space agencies.
However, in an essay posted here, I pointed out that the material shed by 3I/ATLAS will never reach Earth because it is pushed away from Earth by the solar radiation and wind and because of the fact that 3I/ATLAS passed on the other side of the Sun relative to Earth.
- If we assume that 3I/ATLAS is an artificial object, was it controlled by artificial intelligence, or by beings that “awakened” during the flight and will now fall asleep again?
The journey from distant stars takes billions of years so I would expect artificial intelligence (AI) to guide interstellar travel. However, biological passangers are also possible if their life expectancy was extended indefinitely by AI-assisted medicine.
- Earthlings were unprepared for an encounter with another civilization: scientists were immersed in debate and mutual accusations. It turns out we’re unable to contact 3I/ATLAS or catch up with it, and we don’t even want to. We’ve failed the test. What does this mean for the future?
The Rubin Observatory in Chile is expected to discover dozens of new interstellar objects. This argues for a coordinated scientific effort to detect new anomalous objects like 1I/`Oumuamua or 3I/ATLAS 6–12 months in advance of their arrival near Earth, so that we can design space missions to intercept them. This calls for a comprehensive network for the discovery and characterization of interstellar objects, as discussed here. The collected data will help policy makers calibrate future objects on the Loeb Scale, and initiate an appropriate defense of Earth from potential threats of alien technology. We must be prepared to assess the risk from black swan events even if we expect most interstellar objects to be natural icebergs.
- If we don’t change anything, will Earth be subjugated to another intelligence, or simply abandoned to its fate? When might this happen?
It is possible that Earth is already being visited, if claims about Unidentified Anomalous Phenomena (UAP) in the Earth’s atmosphere or oceans are correct. I am leading the Galileo Project (discussed most recently here) that operates three new observatories in search for extraterrestrial artifacts near Earth. If we discover anything, I will be better positioned to answer your question with substantive information.
- Could other civilizations infiltrate our (our own) artificial intelligence and subordinate our lives to their own interests?
This is a concern. When engaging in a blind date, you never know whether your dating partner is friendly or a serial killer. I am optimistic that we will benefit more than we will lose from encountering a superior intelligence. You may call me romantic. I believe that the best is yet to come.
- Will “contact” even happen as it’s described in science fiction (a craft lands on Earth, creatures emerge, journalists take photographs, and leaders shake hands)?
It is very unlikely that our imagination is sufficiently evolved to anticipate the characteristics of an encounter. The scripts of science-fiction writers in Hollywood are based on a training data set limited to Earth. Interstellar visitors have a much larger training data set, because there is much more real estate beyond Earth. This is why we should always look up at the vast expanses of cosmic space (measured in billions of light years) and time (measured in billions of years) if we wish to learn something new. Even in our most ambitious scientific projects, we study the “known unknowns” but our biggest step forward will result from finding “unknown unknowns”. These are things that we do not even realize that we do not know.
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.
Professional website:
https://lweb.cfa.harvard.edu/~loeb/
Social media:
https://avi-loeb.medium.com/
https://www.youtube.com/@ProfessorAviLoeb
https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd
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