There’s a visitor in town, and its name is 3I/ATLAS. The presumed interstellar comet presents a rare opportunity for astronomers to study an object born a long time ago in a star system far, far away. But a new paper uploaded to the preprint arXiv server asks an intriguing question: Is the object actually alien technology?
For Harvard astronomer and study co-author Abraham Loeb, this is not his first interstellar rodeo. In 2018, Loeb proposed that the interstellar object ‘Oumuamua might be an alien probe. He’s now back at it, along with co-authors Adam Hibberd and Adam Crowl from the UK’s Initiative for Interstellar Studies, asking the same question about 3I/ATLAS.
The team is essentially flagging 3I/ATLAS as a candidate for alien technology and, perhaps alarmingly, as something that might actually pose an existential threat to humanity. Sounds absolutely bonkers, but it’s a topic worth exploring and not something to reflexively toss onto the garbage heap.
Almost certainly a comet
From the moment it entered our view, 3I/ATLAS—the third interstellar object ever detected in our solar system—instantly became the biggest news in astronomy for the month, if not the year. Astronomers are using the rare opportunity to study the object in as much detail as possible using the best instruments available. A clear picture of the object is emerging, suggesting it’s very likely an enormous, icy comet that’s considerably older than our solar system; preliminary estimates suggest it’s 0.74 miles long (1.2 kilometers) and dates back some 7 billion years.
The interstellar interloper is zipping through our solar system at ludicrous speeds, clocking in at 37 miles (60 kilometers) per second. Its velocity is so extreme that it’ll exit our solar system and disappear from our view later this year, escaping the gravitational influence of our Sun. Astronomers are therefore under a tight deadline to understand everything they possibly can about 3I/ATLAS—an object that originated in some faraway protoplanetary or planetary system.
That said, astronomers have already made some great strides in sketching out the finer details of 3I/ATLAS, quickly churning out papers pertaining to the visitor’s age, size, velocity, spin, and, most importantly, its origin, based on observational data. According to research released earlier this week, the object is a jumble of organic molecules, silicates, and carbon-based minerals, placing it in a similar compositional category as asteroids found between Mars and Jupiter.
Based on current data—much of it from researchers working with the newly launched Vera C. Rubin Observatory—3I/ATLAS is expected to pass through the asteroid belt between Mars and Jupiter later this fall, reaching its closest point to the Sun in late October. Excitingly, the Sun’s warmth should sublimate enough ice on the comet to brighten the coma and tail even further.
Occam’s comet
Suffice it to say, astronomers’ ongoing investigations into 3I/ATLAS largely confirm that it’s a cometary castaway. Like other comets we’ve seen before, 3I/ATLAS likely emerged from natural processes and was banished to interstellar space by some gravitational interaction, such as a close encounter with a gigantic planet or a passing star. Importantly, and despite strange, unfounded claims made in the new Loeb paper, there’s zero indication that 3I/ATLAS is anything but a natural object formed by natural processes.
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