Astronomers have released the first results from an in-depth study on the suspected interstellar object that flew into our Solar System last month – and the findings are fascinating.
The object is known as 1I/2017 U1 (`Oumuamua), a Hawaiian name that means “reach out for” (‘ou) and “first, in advance of” (muamua). The letter “I” denotes that this is our first ever recorded interstellar visitor, confirmed by this study.
Published in Nature, the results show that the object is a bizarre elongated shape, measuring 10 times as long as it is wide. Its length is thought to be at least 400 meters (1,300 feet) long. It spins on its axis once every 7.3 hours, with a large variation in brightness revealing its odd shape.
The observations also confirmed this object – now certain to be an asteroid rather than a comet, as it had no visible coma – was dark and reddish in color. This was the result of cosmic rays blasting it for the millions of years it has been traveling through space, irradiating its surface.
It also appears to be dense, meaning it is possibly rocky or has a high metallic content, and lacks any significant water ice.
"What we found was a rapidly rotating object, at least the size of a football field, that changed in brightness quite dramatically," Karen Meech from University of Hawaii's Institute for Astronomy (IfA), the study’s lead author, said in a statement. "This change in brightness hints that `Oumuamua could be more than 10 times longer than it is wide – something which has never been seen in our own Solar System."