According to researchers at Queen’s University Belfast, the first ever interstellar visitor to our solar system has had a violent past.
When compared to most asteroids and comets we see in our own solar system, ‘Oumuamua’ is very unusual. It flew through our solar system in October and was originally thought to be a comet, then it was later revealed as a cucumber-shaped asteroid.
Since October, researchers have been analyzing the brightness measurements of the object. They discovered that ‘Oumuamua wasn’t spinning periodically like most of the small asteroids and bodies that we see in our solar system. Instead, it is tumbling, or spinning chaotically, and could have been for many billions of years.
It is difficult to pinpoint the exact reason for this and astronomers believe that`Oumuamua impacted with another asteroid before it was fiercely thrown out of its system and into interstellar space.
“Our modelling of this body suggests the tumbling will last for many billions of years to hundreds of billions of years before internal stresses cause it to rotate normally again,” said Dr Wes Fraser at Queen’s University Belfast.
“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.”
Until now, scientists had been puzzled that `Oumuamua’s colour varied between measurements. However, Dr Fraser’s research has now revealed that its surface is spotty and that when the long face of the cucumber-shaped object was facing telescopes on Earth it was largely red but the rest of the body was neutral coloured, like dirty snow.
“Most of the surface reflects neutrally but one of its long faces has a large red region. This argues for broad compositional variations, which is unusual for such a small body,” said Fraser, adding 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.