A massive comet known as 3I/ATLAS that was first discovered zooming across the solar system over the summer showed signs of “non-gravitational acceleration” and appeared to have turned blue as it passed the Sun, according to scientists.
According to a report from Avi Loeb, Baird Professor of Science and Institute Director at Harvard University, the non-gravitational acceleration was first indicated by NASA in a recent report, and indicated that expected outgassing from the comet would mean it would lose half its mass and show a massive debris plume in the coming months.
New image of the comet 3I/ATLAS from the Hubble Telescope
(NASA)
The problem is – Earth-based telescopes can’t get a good look at 3I/ATLAS to see if that’s occurring because it’s being hidden behind the Sun. However, it’s expected to reappear in early December and that will allow for ground-based observations.
In the meantime, NASA and other partners, like the European Space Agency (ESA), have been using spacecraft to track 3I/ATLAS.
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But, what if, once 3I/ATLAS comes into better view, it doesn’t appear to have lost any sort of mass?
“Alternatively, the non-gravitational acceleration might be the technological signature of an internal engine,” Loeb wrote in his report.
ExoMars TGO images comet 3I/ATLAS taken in October 2025.
(ESA / FOX Weather)
In response to a question about 3I/ATLAS from Kim Kardashian, NASA Acting Administrator Sean Duffy said there isn’t anything to worry about.
“@NASA’s observations show that this is the third interstellar comet to pass through our solar system,” he said in a post on X. “No aliens. No threat to life here on Earth.”
In his report, Loeb said that massive evaporation of 3I/ATLAS could explain its intense blue light, citing a recent paper. “For a natural comet, this blue color is very surprising,” he wrote, saying that dust would result in having a redder color than the Sun.
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“(The blue color) could potentially be explained by a hot engine or a source of artifical light,” Loeb continued. “However, it might instead be a signature of ionized carbon monoxide for a natural comet.”
Comet 3I/ATLAS was expected to make its closest approach to the Sun on Oct. 30, reaching about 130 million miles (210 million km) from our star. The ESA said ESA its Jupiter Icy Moons Explorer (Juice) would next observe the comet on Nov. 2 and Nov. 25.
According to a report, 3I/ATLAS is expected to make its closest pass to Earth on Dec. 19 at about 167 million miles away. That’s when scientists could determine whether the object is a comet or some sort of artifical craft.
