Astronomers believe second Earth-like planet is hiding in deep space
A second Earth-like planet could be hiding in the depths of our solar system beyond Neptune, according to astronomers based in Japan.
Patryk Sofia Lykawka and Takashi Ito have been studying the Kuiper belt, a massive ring of objects in the outer solar system, just beyond Neptune. The belt is like a stellar motorway, filled with millions of objects up to 60 miles wide including asteroids, rocks and comets racing around the Sun.
Research conducted by Mr Lykawka, of Kindai University, and Mr Ito, from the National Astronomical Observatory of Japan, suggests that unusual behaviour by some of these objects can only be explained by the presence of a planet.
In particular, the team found a large number of objects with a high-tilt orbit, meaning they are tilted on their axis more than would be expected.
Their calculations suggest it is one-and-a-half to three times the size of Earth, orbiting the Sun with the Kuiper belt.
The orbit would be between 250 and 500 astronomical units (AU) from the Sun, where 1 AU is 93 million miles.
This new proposed planet is closer to Earth than the theoretical Planet Nine, a planet in the outer edges of the solar system beyond the Kuiper Belt which has been hypothesised by several well-regarded studies.
Writing in The Astronomical Journal, the team said: ‘In conclusion, the results of the KBP scenario support the existence of a yet-undiscovered planet in the far outer solar system.
‘More detailed knowledge of the orbital structure in the distant Kuiper Belt can reveal or rule out the existence of any hypothetical planet in the outer solar system.’
However, even if the Kuiper Belt planet is confirmed, getting classification as an official planet may still prove difficult.
Pluto was once known as the ninth planet of the solar system, gracing classroom posters across the world. But in 2006 it was unceremoniously downgraded to a dwarf planet after failing to fulfill all three criteria for a planet as set out by the International Astronomical Union.
The rules state planets must be in orbit around the Sun, have sufficient mass to assume hydrostatic equilibrium – are almost round in shape – and have ‘cleared the neighborhood’ around their orbit.
Sadly in the case of Pluto, and any other would-be planet in the Kuiper Belt, this third criteria cannot be met.
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