Chaotic Space Collision Finally Explains Origins of Interstellar Asteroid Oumuamua
Just when you thought Oumuamua couldn't surprise us anymore, astronomers have announced that the strange, cigar-shaped object that represents the first visitor from outside our solar system isn't cruising through space like a bullet—it's actually tumbling at high speed, and will continue to do so for the next few billion years.
One of the most interesting theories about Oumuamua was that it was some kind of alien spacecraft, or maybe an extraterrestrial Whale Probe from an alien civilization, similar to the one that visited Earth in Star Trek: The Voyage Home. Both of these theories assumed that Oumuamua traveled through space like a rocket would, but the new study in Nature Astronomy has claimed that the object "appears to be in an excited rotational state undergoing non-principal axis rotation."
In normal language, this means Oumuamua is spinning around wildly, possibly because something collided with it a long, long time ago, during the formation of its home solar system.
The best way to confirm this would be spotting an impact crater on its surface, but so far astronomers haven't been able to get the necessary high-res photos to spot it. In any case, we can probably rule out the alien spaceship/probe hypothesis.
So what exactly is Oumuamua?
According to scientists' best guesses, it's a chunk of ice covered in a shell of "dark-red carbon gunk," which has turned into an organic form of sunscreen that ensures the ice inside doesn't melt (which would transform Oumuamua into a comet). Professor Alan Fitzsimmons at Queen's University Belfast calls it "[cometary] in composition, but asteroidal in appearance."
Between its organic insulation, weird trajectory, and ancient past, Oumuamua is probably the most interesting asteroid/comet thing in our solar system right now—hopefully we can learn even more about it before it leaves.