Planet Nine could destroy our solar system, scientists say

After our sun dies – in about seven billion years – the mysterious planet hovering on the edge of our solar system could also be its undoing

Artist's impression showing Planet Nine causing other planets in the solar system to be hurled into interstellar space

(University of Warwick)

Our solar system could be unexpectedly destroyed when the sun dies, because of a mysterious planet hovering at its edge.

Until now, most scientists had assumed that many of our neighbours – Jupiter, Saturn, Uranus and Neptune – would be able to survive the death of our star. They had predicted that the inflation of the Sun would swallow the Earth but would then become a white dwarf, pushing those planets to a safe distance.

But if there really is a Planet Nine hovering on the edge of our solar system then it could disrupt that happy ending, according to new research. That planet, which scientists increasingly believe exists, might not be pushed out to a distance and instead create a violent future for those planets that are still around.

At least one of those existing planets will probably be thrown out into interstellar space because of the strange potential make-up of our solar system, according to new research from Dimitri Veras at the University of Warwick.

The work was done using a special code that can simulate the death of planetary systems. When the hypothetical Planet Nine was added to the mix, the projection changed dramatically – it showed that the further away and bigger the planet is, the more likely it will lead to the solar system undergoing the predicted violent future.

Scientists are still unsure whether Planet Nine actually exists, and at the moment ideas are mostly based on the strange movement of other objects in the far distance of our solar system. But if it does it could change the way we view our own solar system – and others that seem to have experienced the same effects in the past.

"The existence of a distant massive planet could fundamentally change the fate of the solar system,” Dr Veras said in a statement. “Uranus and Neptune in particular may no longer be safe from the death throes of the Sun. The fate of the solar system would depend on the mass and orbital properties of Planet Nine, if it exists.

"The future of the Sun may be foreshadowed by white dwarfs that are 'polluted' by rocky debris. Planet Nine could act as a catalyst for the pollution. The Sun's future identity as a white dwarf that could be 'polluted' by rocky debris may reflect current observations of other white dwarfs throughout the Milky Way.”

Dr Veras’s research is published in the Monthly Notices of the Royal Astronomical Society, under the title ‘The fates of solar system analogues with one additional distant planet’.