Could a large, cigar-shaped object floating through space be part of an alien spacecraft? Astronomers at Harvard University don’t rule it out in a recent paper.
Scientists spotted the object in October 2017, at first thinking it was a comet or an asteroid, and later wondering if it’s a kind of interstellar object that we’ve never seen before. Its nickname is “‘Oumuamua,” Hawaiian for “a messenger that reaches out from the distant past.”
In a paper that has not yet been published in a peer-reviewed journal, Abraham Loeb and Shmuel Bialy of the Harvard-Smithsonian Center for Astrophysics write that ‘Oumuamua could be “produced naturally, through a yet unknown process.” Yet they also suggest that it could be a lightsail or solar sail—i.e., a spacecraft that runs on sunlight.
“[O]ne possibility is that ‘Oumuamua is a lightsail, floating in interstellar space as a debris from an advanced technological equipment,” they write. “Alternatively, a more exotic scenario is that ‘Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization.”
Other scientists responded skeptically to the these suggestions.
“I am distinctly unconvinced and honestly think the study is rather flawed,” Alan Jackson, a fellow at the Centre for Planetary Sciences at the University of Toronto Scarborough, wrote in an email to CNN. "Carl Sagan once said, ‘extraordinary claims require extraordinary evidence’ and this paper is distinctly lacking in evidence nevermind extraordinary evidence."
However, some astronomers pointed out that the fact that Loeb and Bialy brought up this theory in their paper doesn’t actually mean they believe it.
“The thing you have to understand is: scientists are perfectly happy to publish an outlandish idea if it has even the tiniest *sliver* of a chance of not being wrong,” tweeted astrophysicist Katherine J Mack, a physics professor at North Carolina State University. “But until every other possibility has been exhausted dozen times over, even the authors probably don’t believe it.”
What’s the upside of including bizarre theories like that in a paper? Well, for one, it motivates media outlets to pick up your story, generating publicity it might not have received otherwise. Even though sometimes a cigar-shaped space object is just a cigar-shaped space object.