It's been dubbed a comet, an asteroid, and a new class of interstellar object. Now, a paper from Harvard astronomers suggests one more possibility into the mysterious object nicknamed "Oumuamua": Alien probe.

Researchers focused on whether solar radiation pressure could explain the unusual acceleration of "Oumuamua," the first object entering the Earth's solar system from interstellar space.

The paper said if solar radiation pressure is the reason "Oumuamua" is moving at high speeds, it represents "a new class of thin interstellar material" either made naturally or through artificial means.

The paper's authors, which include Avi Loeb, chair of Harvard's astronomy department, suggest the object could be a "lightsail" used to propel spacecraft with solar energy.

The other possibility? It comes from aliens. "A more exotic scenario is that 'Oumuamua'

may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization," reads the paper.

The paper was posted on Cornell's University arXiv e-print archive, where research is submitted before it is formally published. The paper was also submitted to The Astrophysical Journal Letters.

"Oumuamua" has confounded researchers since it was first spotted last year by the Pan-STARRS1 telescope atop Mount Haleakala in Maui, Hawaii. The name "Oumuamua" is Hawaiian for "scout" or "messenger."

The object puzzled astronomers because of its long shape and unusual acceleration. According to NASA, "Oumuamua" is up to a quarter-mile long and has reached speeds of 196,000 miles per hour.

In June, a study led by astronomer Marco Micheli of the European Space Agency found the object was a comet, noting "Oumuamua" was not slowing down as much as expected because of gravitational forces.

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Follow Brett Molina on Twitter: @brettmolina23.