That is the highly speculative conclusion of Shmuel Bialy and Avi Loeb of Harvard University, who say that the unexplained trajectory of the object as it travelled through the solar system could be the result of it being accelerated by sunlight.
However, according to a recent article from two Havard researchers, Oumuamua could be something completely different, namely a "fully operational probe sent voluntarily near the Earth by an extraterrestrial civilization".
A mysterious cigar-shaped object spotted tumbling through our solar system a year ago may have been an alien spacecraft sent to investigate Earth, astronomers from Harvard University have suggested. And even if the shape could hold up against interstellar weathering, it would still be a form unlike anything that exists on Earth, or anything that could exist under the currently-understood laws of astrophysics. Named after the Hawaiian word for "scout" to commemorate its interstellar voyage, the cigar-shaped object has both a highly eccentric orbit and a shiny surface, leading some astronomers to identify it as a comet.
"This would account for the various anomalies of 'Oumuamua, such as the unusual geometry inferred from its light-curve, its low thermal emission, suggesting high reflectivity, and its deviation from a Keplerian orbit without any sign of a cometary tail or spin-up torques". For this to happen, however, 'Oumuamua must less than 1 mm thick and be just a few metres across - which is much smaller and thinner than previously thought.
"It is exciting to live at a time when we have the scientific technology to search for evidence of alien civilizations", Loeb wrote in an email.
The Harvard researchers say that Oumuamua could be a solar light sail, created to be carried along by the solar wind. Bialy and Loeb concluded maybe it came from an "artificial origin", implying that it was made by something other than natural formation.
What we do know is the Oumuamua is the first object ever seen in our solar system that is known to have originated elsewhere.
"Like most scientists, I would love there to be convincing evidence of alien life, but this isn't it", Alan Fitzsimmons, an astrophysicist at Queens University, Belfast, told AFP. "It is impossible to guess the goal of Oumuamua without more data".