For decades, scientists had theorised there is a ninth planet – what would have been 10th were it not for the downgrade of Pluto to a dwarf planet – in our galactic neighbourhood. The planet is believed to be 10 times bigger than Earth and 20 times farther away from the sun than Neptune – the outer-most planet in the solar system. While Planet Nine’s existence had not been officially proven, esteemed researchers strongly suspected there is a large planet lurking in the far edge of our solar system.
If the planet was there, then it could explain why the solar system is slightly off balance.
In most star systems, the surrounding planets tend to rotate in line with their host.
However, in our solar system, the planets are at an angle of six degrees off its axis.
Scientists had thought it was due to a large planet pulling the solar system slightly off kilter, but now they believe it could simply be due to a circumstellar ring of asteroids – known as the Kuiper Belt – tugging on our galactic neighbourhood.
Cambridge University student Antranik Sefilian said: “The Planet Nine hypothesis is a fascinating one, but if the hypothesised ninth planet exists, it has so far avoided detection.
“We wanted to see whether there could be another, less dramatic and perhaps more natural, cause for the unusual orbits we see.
“We thought, rather than allowing for a ninth planet, and then worry about its formation and unusual orbit, why not simply account for the gravity of small objects constituting a disk beyond the orbit of Neptune and see what it does for us?”
The researchers say the objects in the Kuiper Belt contains billions of asteroids known as Trans-Neptunian Objects (TNOs) which could be the reason for the slightly strange orbital patterns.
Former tutor of Mr Sefilian, Professor Jihad Touma, from the American University of Beirut, said: “If you remove Planet Nine from the model, and instead allow for lots of small objects scattered across a wide area, collective attractions between those objects could just as easily account for the eccentric orbits we see.
“While we don’t have direct observational evidence for the disk, neither do we have it for Planet Nine, which is why we’re investigating other possibilities.
“It’s also possible that both things could be true – there could be a massive disk and a ninth planet.
“With the discovery of each new TNO, we gather more evidence that might help explain their behaviour.”