Oumuamua, the first interstellar object spotted in the solar system, could very well be an alien spacecraft, two Harvard researchers say.
The size of a stadium, Oumuamua is flat and elongated, and accelerated as it tumbled past the sun. It's very different from the typical asteroid or comet, and in a paper that will be published Nov. 12 in The Astrophysical Journal Letters, Avi Loeb and Shmuel Bialy write that it "may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization."
It's possible Oumuamua sped up when it went past the sun because it has a "lightsail of artificial origin," Loeb and Bialy say in their paper. More data is needed to determine what Oumuamua is, Loeb told NBC News MACH, but it's already left the solar system, and is no longer visible to telescopes. Both know this speculation is "exotic," but Loeb contends it's "purely scientific and evidence-based," with the scientists following "the maxim of Sherlock Holmes: When you have excluded the impossible, whatever remains, however improbable, must be the truth." Learn more about Oumuamua by watching the video below.Catherine Garcia