Finding out about Planet Nine: Scientists tell us how they found the extra planet in our solar system

IT COULD be ten times the size of Earth and take 20,000 years to get round the sun. Watch the video about the possible extra planet in the Milky Way.

ASTRONOMERS and scientists are very excited about the news of a possible extra planet in our solar system.

Tentatively named ‘Planet Nine’, it was discovered by researchers at the California Institute of Technology (Caltech) .

Early signs show that the mysterious planet could be 10 times more massive than the Earth.

“There have only been two true planets discovered since ancient times, and this would be a third. It’s a pretty substantial chunk of our solar system that’s still out there to be found, which is pretty exciting,” said Professor Michael E Brown, one of the researchers at Caltech.

The theory of another planet came after the scientists looked at six smaller objects in the outer solar system, beyond Neptune. As these objects travel around the Sun, they all orbit in the same elliptical direction in a way that shouldn’t happen.

“We realised that the only way we could get them to swing in the same direction is if there is a massive planet – also very distant in the solar system – keeping them in place while they all go around the sun,” said Prof Brown.

Wide orbit
Unlike the orbit of the known planets, the orbit of Planet Nine would be exceptionally wide.

So, while the Earth takes one year to orbit the sun and Jupiter takes 12, the orbit of Planet Nine is estimated at 20,000 years.

Finding Planet 9

Professor of Planetary Astronomy Mike Brown speaks in front of a computer simulation of the probable orbit of Planet Nine (yellow) at the California Institute of Technology in Pasadena, California. (Image: REUTERS/Mario Anzuoni)
The team behind the discovery believe that there is a chance that telescopes here on Earth could be strong enough to spot the mysterious extra planet.

The Keck telescope and Suburu telescope , both in Hawaii, could potentially focus in on it.

“I’m really hoping that as we announce this people start a worldwide search to go find this ninth planet,” said Professor Brown.