Mundane wayward space snowball, or extraterrestrial visitor?
Astronomers believe that our solar system’s latest and only third ever confirmed interstellar visitor, 3I/ATLAS, is almost certainly a comet.
But lingering questions about the object means it’s not yet an open and shut case. Amid that uncertainty, famed Harvard astronomer Avi Loeb is pushing the possibility that the interstellar interloper is an “extraterrestrial artifact” — perhaps even an “alien mothership” — here to menace or observe us. Which, though it sounds scary, could be interpreted as a good thing.
“The discovery of an extraterrestrial artifact would reset our priorities to explore the real estate beyond Earth instead of just focusing on terrestrial conflicts,” Loeb wrote in a recent blog post. “Humanity desperately needs a wakeup call.”
Loeb acknowledges that the odds aren’t in his favor — but only slightly. Presently, on his detailed scale of one to ten for classifying the likelihood of interstellar objects representing a piece of alien technology, he gives 3I/Atlas a “four” — an “anomaly meeting potential technosignature criteria.”
“Having a 40 percent chance for an accident while crossing the street, argues in favor of keeping our eyes open and monitoring an approaching car,” he argues in the post.
The claims are controversial, but this isn’t new territory for Loeb. He has long argued that ‘Oumuamua, the first detected interstellar object in history, may have actually been an alien probe. The nearly quarter-mile object’s unusual acceleration could have been a sign that it was being propelled with a solar sail, he argued.
In early July, astronomers confirmed that 3I/ATLAS, named after the telescope in Chile which first spotted it, came from interstellar space, making it the third detection ever of such an object. It followed the discovery of 2I/Borisov in 2019, which was also believed to be a comet.
The main giveaway was its blistering speed. Traveling at over 130,000 miles per hour, it vastly outpaces anything in our solar system, and would have had to reach its incredible speed outside the speed limit imposed by the Sun. The prevailing theory is that 3I/ATLAS originated in a star system near the center of our galaxy, and was propelled our way after being ejected from its home by a gravitational disturbance like a passing star.
The suspicion from the get-go has been that 3I/ATLAS is a comet. Images taken with the Hubble Space Telescope, for example, show evidence of a coma, the luminous halo of gas and dust that gives comets their flashy appearance, which form when the Sun warms the ice in the comet’s solid core, leading to “outgassing.” Loeb acknowledges the coma on his own blog.
But a puzzling wrinkle in this theory that Loeb picks apart is the fact that 3I/ATLAS doesn’t possess a cometary tail — which is extra strange, since it‘s traveling toward the Sun. He also goes in on its highly unusual trajectory: that it just so happens to travel along the same plane that most of the planets of our solar system orbit the sun. And maybe that’s not an accident, suggests Loeb.
“The chance of it being on that plane is one in 500,” Loeb told The Times in a recent interview, noting that its timing means it will fly remarkably close to Jupiter, Mars and Venus. This “raises the question of whether this trajectory was designed.”
Loeb also points out how his colleagues have gotten it wrong in the past. In his blog, he cites the amusing example of the Minor Planet Center nearly announcing a new near-Earth asteroid — until astronomers realized the object just so happened to follow the orbit of the Tesla Roadster that Elon Musk launched into space back in 2018.
“Recognizing that this object is not a rock but a technologically-manufactured car required knowledge that SpaceX launched such a car,” Loeb wrote. “Without that knowledge, as would be the case for an interstellar probe, this car would have been cataloged, even today, as a rocky asteroid.”
Does that mean that aliens should be the next explanation in line? Peter Veres, a fellow Harvard astronomer who works at the Minor Planet Center, has a less sensational theory for 3I/ATLAS’s strange behavior. Per The Times, he believes the comet developed a crust on its surface while traveling through interstellar space that was “baked” and hardened by cosmic rays. Once it gets closer to the Sun, he believes, the crust “will peel off and suddenly we’ll see a lot of activity.”
As for its strange trajectory? Veres emphasizes that we’re only dealing with a sample size of three. “The previous two objects were on totally random angles,” he told The Times. We’ll know what’s an ordinary trajectory once we track 30 to 100 interstellar objects, he added.
Granted, Loeb himself is hoping he’s wrong. “I would be relieved to know that it is an icy rock, because in that case — humanity will not face any risk,” he wrote.
More on space: Scientists Detect Precise Origin of Mysterious Signal From Deep Space
