Tumbling alien asteroid had a 'violent past

Earth’s first visitor from outside our solar system arrived after hitting another space astronomical body billions of years ago, scientists say.

The inter-stellar asteroid Oumuamua is the subject of new research by the UK’s Queen’s University Belfast.

The “space cucumber”  - a giant space rock - enthralled astronomers when it flew into the path of telescopes over Hawaii last October, reports the UK Independent.

Oumuamua’s unusual long, thin shape was unlike anything seen by scientists and space buffs, with some enthusiastic types suggesting it may be an alien space craft.

And when it was spotted last year it was the first observation of a planetesimal – an asteroid or comet born in a different planetary system to Earth’s.

But the latest research, published in the journal Nature Astronomy, throws light on its origins and its trajectory.

“We now know that beyond its unusual elongated shape, this space cucumber had origins around another star, has had a violent past, and tumbles chaotically because of it,” said Dr Wesley Fraser, of Queen’s University Belfast.

After they examined the measurements of Oumuamua’s brightness over time, the scientists found it takes a random path through space.

Unlike most solar system bodies that spin periodically, it instead tumbles chaotically.

“While we don’t know the cause of the tumbling, we predict that it was most likely sent tumbling by an impact with another planetesimal in its system, before it was ejected into interstellar space,” Dr Fraser said.

The scientists believe Oumuamua is likely to be an asteroid and not an alien space craft.

More than 46 million similar interstellar objects journey through our solar system every year, researchers have suggested.