Press enter or click to view image in full sizeThe discovery image of 3I/ATLAS by the ATLAS telescope in Chile on July 1, 2025. (Credit: ATLAS/University of Hawaii/NASA)
The object 3I/ATLAS is a rare gift from interstellar space. Its large size and near alignment with the ecliptic plane made it observable by Mars orbiters last week, with the first official report from ESA’s CaSSIS camera yesterday (accessible here) and even better data anticipated from NASA’s HiRISE camera in the coming days or weeks.
In a few interviews last night (posted here and here) and new ones this morning, I was asked about the long-term lessons from our encounter with 3I/ATLAS . Below is a list of selected questions along with my answers:
Why is the frontier of studying interstellar objects so important for science?
Interstellar objects take millions to billions of years to arrive into the inner solar system from their origin and allow us to have a sample of the materials present in their parent systems. It would take our spacecraft millions to billions of years to travel and examine these materials near their origins. The possibility to do this study here and now opens a new frontier of research because interstellar objects bridge the gap of time and space between Earth and the Milky-Way galaxy at large. In particular, this new frontier offers unimagined opportunities in astrobiology for studying the building blocks of life near other stars from sample return of natural materials as well as technological products of other civilizations.
Rep. Anna Paulina Luna has been keeping in touch with you and voicing concerns about possible probes. Let’s say probes were detected, is the US government ready to respond accordingly and what do you think the correct course of action would be?
As far as I know, there are no protocols for responding to the discovery of functioning alien devices near Earth. The situation is different from detecting radio signals from a source located thousands of light years away. A visitor in our backyard requires immediate attention because it could enter through the front door and pose an imminent threat. In 2005, the U.S. Congress tasked NASA to identify 90% of all space rocks that may collide with Earth and have a size bigger than a football field (140 meters). However, alien technology is much more unpredictable than rocks and we do not have a contingency plan on how to search and respond to such a threat. A week ago, I submitted a white paper to the United Nations (available here) and encouraged the international community to establish a committee that will address possible threats from interstellar objects.
Do you think NASA and other agencies know more than they let on about the “comet”?
No. In particular, I believe that the recent delay in the dissemination of data from NASA as a result of the government shutdown does not flag extraterrestrial intelligence but rather terrestrial stupidity.
NASA recently said they believe to have found evidence of ancient alien life on Mars — do you reckon it’s possible that an ancient civilization on Mars could be connected to 3I/ATLAS?
Not likely.
If you were going to design and launch a probe to another system, what sort of craft and flight profile (mission) would you design? Would it be anything like ATLAS?
In my view, we should assign a higher priority to the design of a space platform that could carry humans to interstellar space than to less ambitious plans to migrate from Earth to Mars. The conditions on the surface of Mars are harsh and not suitable for humans. A spacecraft on the scale of kilometers could generate artificial gravity through rotation. The main challenge is the power demand to nurture a self-sustained habitat. If humanity will allocate half of its military budgets to this challenge, of order a trillion dollars per year, then I believe that engineers, scientists and space architects might come up with practical designs by the end of this century. Detecting spacecraft manufactured by more advanced alien technologies can inspire us to reverse-engineer and duplicate them.
What is the probability that you assign to a technological origin of 3I/ATLAS?
As of now, I assign a 30–40% likelihood that 3I/ATLAS does not have a fully natural origin, based on its seven anomalies that I listed here. This low-probability scenario includes the possibility of a black swan event akin to a Trojan Horse, where a technological object masquerades as a natural comet. My rank is likely to evolve in response to new data over the next few months, such as the observations by the Juice spacecraft during the month of November 2025, the observations by hundreds of ground-based and space-based observatories during its closest approach of 3I/ATLAS to Earth at a geocentric distance of 269 million kilometers on December 19, 2025, as well as the data from the Juno spacecraft when 3I/ATLAS arrives within 54 million kilometers from Jupiter on March 16, 2026. These observations will also inform us of any non-gravitational maneuvers or fragmentation of 3I/ATLAS.
How should humanity address the risk from alien technology in the coming decade?
We have no idea on the amount of traffic of extraterrestrial probes in the vicinity of the Solar system. Given the uncertainty, it would be prudent to collect as much data as possible on interstellar objects from all directions, and assess the level of risk based on that data. A comprehensive study of the entire sky requires an investment at a level of a billion dollars, comparable to the investment of NSF and DOE in the Rubin Observatory for the southern sky. After the first verified encounter with alien technology, the funding level will have to increase by a factor of a thousand, comparable to the global military budget worldwide, because of the severe implications to the world economy.
The known anomalies of 3I/ATLAS motivate a coordinated effort to measure the properties of future interstellar objects to be detected by the Rubin Observatory in the southern sky over the coming decade. To complete humanity’s alert system, it would be prudent to fund a copy of the Rubin Observatory for the Northern sky at a similar cost. Even if no existential threat is identified based on future data, a full sky survey would offer great benefits to science. It is a win-win investment that makes a lot of sense.
ABOUT THE AUTHOR
Press enter or click to view image in full size(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.