Our solar system was visited by an object from another solar system

21 Nov 2017

This artist’s impression shows the first interstellar asteroid, ‘Oumuamua. Image: M Kornmesser/ESO

An interstellar asteroid that drifted past our sun recently has been confirmed to have originated from another solar system.

Our solar system has many visiting chunks of space debris passing through, but we have never found one that has come from another solar system – until now.

A team of astronomers has identified one such cosmic traveller, dubbed 1I/2017 or ‘Oumuamua (the Hawaiian word for scout).

According to The Guardian, the object was first spotted travelling past the sun last month.

At first glance, it looked very similar to the comets and asteroids seen in our own solar system. However, unlike this space debris, ‘Oumuamua’s orbit was calculated as being impossible to achieve by one that originated in our own system and could be one of as many as 10,000 that are nearby.

Contains organic molecules

The object is believed to be an incredibly dark red colour, with 96pc of all light that hits it being absorbed.

The appearance of red means that it contains organic, carbon-based molecules. This could add even greater credence to the theory of transpermia, whereby comets and asteroids containing organic molecules could have collided with Earth and ‘seeded’ life here.

Findings on ‘Oumuamua have been published by two sets of researchers from the University of Hawaii and UCLA, respectively.

The team from Hawaii calculated that ‘Oumuamua is just 400 metres long with a rotation once every 7.3 hours.

The UCLA team estimated that the other 10,000 or so objects similar to the asteroid could be located closer to our sun than Neptune, with three objects arriving and three leaving our solar system on a daily basis.

By better understanding how ‘Oumuamua and other objects like it enter our solar system, we can learn more about how planets formed in their native star system.

Colm Gorey was a senior journalist with Silicon Republic