Oumuamua has been confusing scientists ever since astronomers first sighted it back in 2017.

It's most likely a skyscraper-sized asteroid from another part of the galaxy, but what if it's actually [checks notes] "a fully operational probe sent intentionally to Earth vicinity by an alien civilization."

That's the most "exotic" explanation provided in a paper set to be published Nov. 12 in The Astrophysical Journal Letters, written by researchers from the Harvard Smithsonian Center for Astrophysics. 

Oumuamua is interesting for a number of reasons. First and foremost, it's the first interstellar asteroid of its time ever seen by humans. Secondly, it's an odd shape, being flat and elongated. Thirdly, and perhaps most importantly, it moves strangely. As per the paper, it shows "deviations from a Keplerian orbit at a high statistical significance". In short: It doesn't move like a regular comet or asteroid.

The paper attempts to explain that strange movement and comes up with a number of possible scenarios. The first: solar radiation pressure.

But here's where it gets weird.

"If radiation pressure is the accelerating force," states the paper, "then 'Oumuamua represents a new class of thin interstellar material, either produced naturally, through a yet unknown process in the ISM or in proto-planetary disks, or of an artificial origin."

Artificial. Origin.

The paper goes on to explore the idea that Oumuamua could possibly be a broken off part of an alien probe. That it could be a "lightsail, floating in interstellar space", not unlike the type being built on Earth as part of the Starshot Initiative.

But here's the best part: "Alternatively, a more exotic scenario is that Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization."

It's too late to confirm this theory with chemical rockets or using telescopes, concludes the paper. Our only hope in proving or disproving Oumuamua's potential alien origins lies is finding another similar object, floating through space. 

We might be waiting a while.

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