One of the most bizarre pieces of space news that keeps popping up this year is the story of Oumuamua, a cigar-shaped object that sped through our Solar System so fast that scientists barely had time to glimpse it before it was already headed back out into space. It’s the first interstellar object mankind has ever seen, and it’s sparked a ton of debate over its origins and what exactly it was.
Early on, the object was thought to be a comet, but observers later decided it was obviously an asteroid. The scientific community at large has changed its mind a few times since then, and at this point it’s unclear what the majority of astronomers actually believe, but at least a couple of them are still entertaining the possibility that the object was actually an alien spacecraft. Yes, this is still a thing.
After Oumuamua’s shocking appearance in our system, researchers from the Breakthrough Listen project pointed mechanical ears at it to see if they could hear signals being sent too or from the object. If it were an alien ship, surely it would be communicating with its handlers and we might be able to hear those whispers, or at least that was the plan. Unfortunately, the team heard only silence, but that isn’t stopping some researchers from imagining the possibility of Oumuamua being a spacecraft sent to survey our Solar System or even Earth, specifically.
In a new paper, scientists from the Harvard Smithsonian Center for Astrophysics break down the case for the cigar-shaped object being of extraterrestrial origin. More to the point, they focus on the object’s strange speed changes as it passed through and exited our system. Oumuamua sped up as it left, which is obviously very odd behavior for a rock, which led some scientists to assume it was a comet, spewing out gas and material as it cruised back out into interstellar space.
This new paper suggests that it might be speeding up because it’s equipped with what is known as a “light sail.” A light sail is an advanced, but still theoretical, form of spacecraft propulsion that would use radiation pressure from a star to push an object along, like wind on a sailboat’s sail. If solar particles slam into the sail, it causes the sail and whatever it’s attached to to speed up.
“Considering an artificial origin, one possibility is that Oumuamua is a lightsail, floating in interstellar space as a debris from an advanced technological equipment,” the paper explains, noting the possibility that it might just be a piece of alien space junk that found its way to our system. However, the team follows up with an even more wild theory, saying “a more exotic scenario is that Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization.”
What this paper shows more than anything is that we still have no good explanation for what the object was, why it was here, or how it moved in the way that it did. There are plausible natural processes that might have done the trick, or maybe it really was aliens. We may never know for sure.