Scientists at a Japanese university said Thursday they believed another planet up to two-thirds the size of the Earth was orbiting in the far reaches of the solar system.
Image: This illustration released by Kobe University shows a planet -- half the size of Earth -- which is believed to be in the outer reaches of the solar system.
The researchers at Kobe University have said that their theoretical calculations using computer simulations lead them to conclude it was only a matter of time before the long-awaited "Planet X" was found
The researchers at Kobe University in western Japan said calculations using computer simulations led them to conclude it was only a matter of time before the mysterious "Planet X" was found.
"Because of the very cold temperature, its surface would be covered with ice, icy ammonia and methane," Kobe University professor Tadashi Mukai, the lead researcher, told AFP.
The study by Mukai and researcher Patryk Lykawka will be published in the April issue of the US-based Astronomical Journal.
"The possibility is high that a yet unknown, planet-class celestial body, measuring 30 percent to 70 percent of the Earth's mass, exists in the outer edges of the solar system," said a summary of the research released by Kobe University.
"If research is conducted on a wide scale, the planet is likely to be discovered in less than 10 years," it said.
Planet X -- so called by scientists as it is yet unfound -- would have an oblong elliptical solar orbit and circle the sun every thousand years, the team said, estimating its radius was 15 to 26 billion kilometres.
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