Mystery of ‘Planet Nine’ at the edge of our solar system deepens

Rob Waugh
Is Planet Nine actually there at all? (Getty)

Four years ago, astronomers suggested an incredible idea – that there was a huge, unseen planet in the solar system, orbiting beyond Neptune.

The giant, hidden planet might be 10 times more massive than Earth – and on an orbit which takes 10,000 or 20,000 years to go round the sun.

But is it actually there?

Astronomers have come up with a new explanation which might unravel the evidence for Planet Nine – the wonky orbits of rocks at the edge of our solar system, which scientists believed were caused by nudges from the unseen world.

Bizarrely, it might also explain what killed the dinosaurs, The Register reports.


A new paper presented to the 232nd meeting of the American Astronomical Society in Denver suggest that the odd orbits of ‘trans-Neptunian objeccts’ might actually be to do with the ‘collective gravity’ of other rocks out there.

Co-author Ann-Marie Madigan of the University of Colorado Boulder said, ‘There are so many of these bodies out there. What does their collective gravity do? We can solve a lot of these problems by just taking into account that question.’

Asteroids may also have slammed into bigger objects, altering their orbits – and may have ‘dislodged’ comets which then headed towards Earth.

It’s not impossible one of these caused the collision which wiped out the dinosaurs, the researchers said.

Lead author Jacob Fleisig said, ‘You see a pileup of the orbits of smaller objects to one side of the sun.

‘These orbits crash into the bigger body, and what happens is those interactions will change its orbit from an oval shape to a more circular shape.’

‘While we’re not able to say that this pattern killed the dinosaurs. It’s tantalising.’