Shiny, reddish in color, oblong, somewhere between 300 and 3,000 feet in length and moving at an eye-watering 16 miles a second, the object zoomed into our system and past the sun. When Canadian astronomer Robert Weryk first noticed the thing in a telescope survey in October 2017, it was already on its way out of our system.

Astronomers were baffled by this object, which they named "`Oumuamua." That's Hawaiian for "scout." No one knew for sure what `Omuamua is—or isn't.

Just one leading scientist was willing to say what others may only have been thinking. `Oumumua's speed, course and shape were possible signs it's an alien craft, according to Avi Loeb, a Harvard physicist. "The possibility of an artificial origin for `Oumuamua must be considered," Loeb wrote in a hallmark 2021 study.

Loeb's position—that we should at least entertain the possibility that `Oumuamua is a spacecraft and investigate accordingly—has been controversial, to say the least. Now, a Chinese team is trying to dismantle one key part of Loeb's argument: If `Oumuamua is an alien ship, it might be propelled by a super-thin light-sail that captures particles from stars.

There's no sign of a sail in the scant data we have on `Oumuamua, the Chinese team asserted in their own peer-reviewed study, which has been accepted for publication in the journal Astronomy and Astrophysics and appeared on-line on Wednesday. "We conclude that the possibility of `Oumuamua being a light-sail is extremely unlikely," Shangfei Liu, an astronomer at Sun Yat-sen University in Zhuhai, China, told The Daily Beast.