'Oumuamua most likely not aliens - report

Scientists have decided an interstellar object is probably not related to alien life.

'Oumuamua appeared without warning in 2017, zipping through the solar system from above. After months of analysis of the little data collected, scientists declared it was a comet in 2018.

The comet has an odd shape, it's long and cylindrical and resembles a large floating cigar. New Scientist reports it could have been originally entered space that way, or was ground down to its current shape.

But what's really weird about it is the way it moves, it has accelerated more than can be blamed on gravitational forces, and there's no sign of dust and gases that could cause the acceleration in a comet.

Naturally that led to suggestions that it was an alien spaceship, and some scientists have theorised it's a probe from another planet.

A paper from the Harvard Smithsonian Centre for Astrophysics said an "exotic scenario is that 'Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien probe."

But Matthew Knight at the University of Maryland has poured cold water on that theory after writing a new report on the comet for the journal Nature Astronomy.

"There are plenty of ways to form it that don't involve aliens, and I don't think there's any reason to invoke something that extraordinary unless we rule everything else out," Dr Knight told New Scientist

"Now, 'Oumuamua is too far away to any more observations, so the data we have is all we're going to get until we spot another interstellar object.

"The next time an interstellar object is discovered we'll be better prepared with the things we want to know about it. Maybe next time we'll be able to rule out an alien craft for certain."