Mysterious Planet 9 may be ‘twisting’ the solar system, scientists say

Professor of Planetary Astronomy Mike Brown discussing Planet 9. © Mario Anzuoni
A planet, believed to be the ninth in our solar system, but which has remained mysteriously elusive to astronomers could be causing the “wobble” in our solar system that causes planets to move at a different angle to the sun, according to new research.

“Because Planet Nine is so massive and has an orbit tilted compared to the other planets, the solar system has no choice but to slowly twist out of alignment,” lead author of the study from Caltech Elizabeth Bailey said in a statement.

All planets in our solar system (excluding the hypothetical Planet 9) move around the sun on the same plane, but this plane differs by six degrees to the sun which is tilted from Earth’s perspective.

Planet 9, believed to be ten times the size of Earth, is theorised to orbit the sun at a distance 20 times farther than Neptune and at an even more extreme angle differing 30 degrees to the other planets. These factors could account for the solar system’s tilt as Planet 9’s extreme orbit causes “a multi-billion-year wobble to that system.”

“Mathematically, given the hypothesized size and distance of Planet Nine, a six-degree tilt fits perfectly” Mike Brown, Professor of Planetary Astronomy at Caltech who was involved in the study said in the statement.

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The findings will be published in the Astrophysical Journal this month.

The planet was first theorised in 2014 and cannot receive an official name until it’s existence is confirmed. That could take a while as the planet takes an estimated 15,000 years to orbit the sun, meaning astronomers will have to carefully watch a lot of space to find it.