Science

Did The Sun ‘Steal’ Planet 9 Billions Of Years Ago?

A theory suggested earlier this year, states there may be an extra planet lurking in our solar system, known as Planet 9, and a new study has suggested an interesting theory, that this planet was actually torn away from another sun 4.5 billion years ago.

Did The Sun 'Steal' Planet 9 Billions Of Years Ago?

Planet 9

At the beginning of 2016, two astronomers, Konstantin Batygin and Mike Brown, from the California Institute of Technology, based in Pasadena, claimed that evidence suggested the presence of another planet in the far reaches of our solar system, commonly referred to as ‘Planet Nine’. They believed this world was likely to be 10 times as massive (and four times the size) as Earth and exist far beyond Pluto.

This speculation was the result of strange orbits of some bodies in the Kuiper belt, (the circumstellar disc, beyond Neptune that is like a massive asteroid belt, but instead of rocks, it is mainly comprised of ice), suggesting the presence of something to cause these odd trajectories.

Nobody has actually observed or found Planet 9 yet, in fact we don’t even know if it made or rock, or gas or ice, but scientists around the world are searching for the mysterious world, like a giant space treasure hunt. It has captured many people’s imagination, a strange planet, in our own backyard (to say under our noses is probably taking it to far…) for billions of years and we have only just noticed it. In the meantime, other people are more interested in the origin story, how and where it came from.

Stolen Planet

Initially, the theory went that Planet Nine would have been formed within our own solar system, much closer to the sun than its present position, but as a result of some gravitational event or force, it found itself banished to the outer reaches.

However, a new study, authored by astronomer Alexander Mustill of Lund University in Sweden (in collaboration with colleagues at Lund, and other astronomers in Bordeaux) has suggested a far more intriguing and controversial explanation. By using the latest computer modeling techniques, he has proposed that the planet was an exoplanet, orbiting a different sun, and was ‘taken’ by our sun about four and a half billion years ago and added to the solar system.

Stars are born in clusters, and so in the early phase they are closer to each other and pass by one another, this is when there is the opportunity for planets swap stars. Mustill wrote, “When the sun later departed from the stellar cluster in which it was born, Planet Nine was stuck in an orbit around the sun.”

“It is almost ironic that while astronomers often find exoplanets hundreds of light-years away in other solar systems, there’s probably one hiding in our own backyard,” Mustill added in a statement.  If confirmed, this would be the first exoplanet discovered in our solar system, and more excitingly, Mustill confirms, “This is the only exoplanet that we, realistically, would be able to reach using a space probe”.

This area of research is still very much in its infancy, and while it is interesting to speculate on the origins of Planet Nine, it first needs to be proven to exist before strong declarations of its origin can be confirmed.

If indeed the sun did ‘kidnap’ this planet, then the researchers belief that there would be some evidence on the smaller objects beyond Neptune in the Kuiper Belt, so that is the obvious place to start looking, and could hopefully provide further information, moving our understanding of the universe forward a considerable amount.