It may have made its closest approach to Earth last month, but the mysterious interstellar object 3I/ATLAS continues to fascinate astronomers as it now careens back out of the solar system, never to be seen again.
Recent observations by NASA’s Hubble Space Telescope have caught the attention of Harvard astronomer Avi Loeb. Images taken in November and December show an “intriguing configuration” of three “evolving jets” that jut out of the object at regular angles from each other, as he explained in a recent blog post.
The object’s most prominent appendage by far is still an “anti-tail” that points directly at the Sun, which scientists suspect is the result of the Sun-facing side losing more of its surface mass as it’s warmed up by the approach. That aligns with the most prevalent theory that 3I/ATLAS is a natural comet largely made up of water and carbon dioxide ice that’s visiting us from a distant star system.
But on a smaller scale, three additional and mysteriously symmetrical jets become apparent in the Hubble observations, which Loeb suggests could be associated with “major pockets of ice on the surface of a rotating nucleus” and “triggered by heat conduction through the body of the nucleus.”
Loeb argues that it’s highly unlikely that the rotation axis of these three jets would be perfectly aligned with the direction of the Sun to allow 3I/ATLAS to form the massive anti-tail jet, which “requires stability over longer periods.”
Put differently, he wrote, how could it be that these three jets are perfectly rotating around a much larger anti-tail jet that acts “like the beam of a lighthouse?”
As such, the astronomer once again raised the possibility that 3I/ATLAS could bean alien remnant of an extraterrestrial civilization — a far-fetched theory he’s championed since the object was first spotted back in July. The theory has largely been refuted by other members of the scientific community, including NASA scientists, who have pointed to the wealth of data suggesting it closely resembles a solar system comet, even despite its interstellar origin.
“Are the symmetric triple-jet inner structure or the unlikely alignment of the rotation axis with the direction of the Sun, technological signatures?” Loeb concluded. “Or can they be a natural outcome of gas dynamics?”
As more data emerges about the rare visitor, scientists continue to chip away at Loeb’s alien hypothesis. Last week, an international team of researchers from the alien-hunting astronomy project Breakthrough Listen detailed in a yet-to-be-peer-reviewed paper that the Green Bank Telescope, the largest single-dish radio telescope in the world, did not detect any “candidate signals” emerging from 3I/ATLAS as it made its closest approach to our planet on December 19.
In fact, they argued that 3I/ATLAS is even more familiar than ‘Oumuamua — the first confirmed interstellar object that was detected passing through the solar system back in 2017 — which similarly sparked a debate at the time about the possibility of being an alien space object.
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