Our solar system could soon have a ninth planet - and no, it's not Pluto

There could be a ninth planet in our solar system that's lying in wait to be discovered - and no, it's not Pluto.

Our solar system has eight planets but in recent years, astronomers have theorised there could well be a ninth planet that's hiding in our solar system we've not been able to see yet.

That's because with it being so far away from the sun, it would be dimly lit and akin to finding a needle in a haystack; current telescopes may not be able to detect it either.

However a brand new telescope that will start looking into the skies at the marvel of our solar system in 2025 may just be able to spot it if Japan's Subaru Telescope in Hawaii cannot.

Experts told Live Science the new telescope at Vera C. Rubin Observatory in Chile could find the elusive ninth planet, nicknamed Planet Nine, in the next few years or rule it out for good.

Mike Brown, an astronomer at Caltech, said: "It's really difficult to explain the solar system without Planet Nine but there's no way to be 100 per cent sure [it exists] until you see it."

A stock photo of the Kuiper Belt / PaulFleet, iStock

With the sun from its distance likely to look nothing more than what stars do to us on Earth, it's speculated it could be a gas or icy giant.

Apart from Pluto, which was demoted from a planet to a dwarf planet in 2006, no planets have been found beyond Neptune or the Kuiper Belt, which is a massive ring of asteroids, comets and dwarf planets that orbit the sun beyond it.

In 2004, scientists found Sedna, a potential dwarf planet beyond the belt, had a strange orbit around the sun that hinted another large mass was gravitationally pulling it.

A 2014 study found a similar object in the Kuiper Belt had an orbit similar to Sedna and more have been found since.

The Planet Nine hypothesis was published by Brown and Konstantin Batygin in 2016.

"At the beginning, we didn't say there was a planet because we thought that was a ridiculous thing for there to be," Brown told Live Science.

"But we tried a lot of different things to explain what we were seeing, and nothing else worked.

"Our best estimates are that it's about seven times more massive than Earth."

Other astronomers have reportedly said it's "quite likely" a ninth planet exists but others are not convinced.

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