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A new analysis of the data obtained when the interstellar object Oumuamua flew through the solar system in October 2016 suggests that it is tumbling in a chaotic manner, and that the surface is spotty.
Straight away, 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.
While it is difficult to pinpoint the exact reason for this, it is thought that `Oumuamua impacted with another asteroid before it was fiercely thrown out of its system and into interstellar space. Dr Fraser explains: “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.
To me, this data settles the question about whether Oumuamua is not an artificial structure. It is not. If it were, an impact that would have caused this kind of tumbling would have almost certainly destroyed it. Instead, it likely broke the original bolide up, producing many fragments, including Oumuamua and its elongated shape.
As for the object’s spottiness:
Dr Fraser explains: “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.”
It is really a shame we couldn’t get a closer look before it sped away.