Despite an abundance of data suggesting interstellar object 3I/ATLAS — the third object ever detected ripping through our solar system — is simply a comet, Harvard astronomer Avi Loeb still hasn’t shaken the suspicion that something feels off about the lump of ice and carbon dioxide.
Since its discovery in early July, Loeb has posited that there’s a chance that 3I/ATLAS is instead a piece of technology sent to us by an intelligent extraterrestrial civilization. He pointed out its highly unusual trajectory, which had already brought it suspiciously close to Mars last week, as well as its enormous suspected mass, measuring in at over 33 billion tons, making it orders of magnitude larger than the two previously observed interstellar objects. The object has also been shown to have a highly unusual chemical composition and sport a puzzling “anti-tail” pointing in the direction of the Sun.
Now, in a Q&A posted to his personal blog, Loeb is willing to put a number behind his suspicion.
“As of now, I assign a 30 to 40 percent likelihood that 3I/ATLAS does not have a fully natural origin,” he wrote. “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.”
However, Loeb conceded that data from the European Space Agency’s Juice spacecraft, which is expected to make a close approach of 3I/ATLAS next month, and NASA’s Juno spacecraft, which will be close to 3I/ATLAS when it whips past Jupiter in March, could cause his probability ranking to “evolve.”
The data could shed new light on how 3I/ATLAS is affected by the Sun’s radiation, as those observations would show the comet right after it finishes its closest approach to the Sun. That’s usually when comets are the most active, moving at the fastest speed and sublimating the most material from their surface.
Most recently, NASA released images taken by its Mars Perseverance rover that appeared to show 3I/ATLAS as it blazed by the Red Planet. The European Space Agency also announced this week that its ExoMars Trace Gas Orbiter and the Mars Express spacecraft had snapped pictures of the comet, despite it being up to 100,000 times fainter than the spacecrafts’ usual targets.
“Though our Mars orbiters continue to make impressive contributions to Mars science, it’s always extra exciting to see them responding to unexpected situations like this one,” Colin Wilson, the ESA’s Mars Express and ExoMars project scientist, said in a statement. “I look forward to seeing what the data reveals following further analysis.”
And if 3I/ATLAS does turn out to be an object sent to us from an alien civilization, we could be woefully unprepared, Loeb warned.
“As far as I know, there are no protocols for responding to the discovery of functioning alien devices near Earth,” he wrote in his Q&A. “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,” he added.
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