When the strange, cigar-shaped object known as Oumuamua zipped through our solar system in 2017 it was a momentous occasion for astronomers around the globe. The object appeared to have originated somewhere other than our system, making it the first interstellar visitor ever to be spotted by mankind. It cruised in, zipped around our Sun, and headed back out to space. But what was it? Theories have shifted back and forth between the rock being an asteroid, comet, or some hybrid of the two, but a few select researchers aren’t ready to throw out the possibility that the object was in fact alien-made.
Harvard professor Avi Loeb made a name for himself early on in the investigation of Oumuamua by standing firm by his belief that the long, narrow object could have been some kind of alien probe or maybe a piece of alien space junk. His claims were largely dismissed by his peers, but the years that have passed since Oumuamua came and left haven’t changed Loeb’s stance, and he’s now published a book where he lays out the evidence that supports his theories.
In an interview with Vice, Loeb hits all the major bullet points of his argument. The interview is certainly worth a watch, with Loeb doing a good job of boiling down all the data into something we can all digest. In short, a lot of the things that remain unexplained about Oumuamua also happen to be the best potential evidence that it wasn’t just a rock or brick of ice.
The biggest mystery in the Oumuamua story is why it seemed to speed up as it left our solar system. Typically, an asteroid or other piece of natural space debris would round the Sun rapidly and then slow down as it exited. This is due to the effects of the Sun’s gravity pulling on it as it speeds away. Oumuamua didn’t do this. Instead, it gained speed, which baffled researchers.
Some have suggested that it may have been some marriage of ice and rock and that whatever side of the spinning object was facing the sun heated up enough to sublimate the ice, and those gasses acted like a jet to push it along.
But if we assume for a moment that the object is alien in origin, the question of what kind of alien-made object it is. Loeb suggests a few possibilities, including Oumuamua being some kind of relay spacecraft or that it is used along with many others like it to form a navigational grid in space. His best guess, however, is that it is a piece of alien “trash,” like a defunct exploratory spacecraft akin to our own Voyager probes that will eventually reach other solar systems long after they are dead.
The bummer about all of this is that we’ll almost certainly never know what the object was. It’s long gone now and, because we lack the technology to study it at such a distance, the data that was gathered during its brief appearance in our system is all we have to go on.