An unknown world might exist beyond the orbit of Pluto, says a new computer model.
Emerging reports say the hidden world -- said to be much bigger than Pluto -- based on the model could explain unusual features of the Kuiper Belt, a region of space beyond Neptune littered with icy and rocky bodies.
The report says if the new world is confirmed, it will not be technically considered a planet. Under a controversial new definition adopted by the International Astronomical Union last week, it would instead be the largest known "plutoid."
Scientists say such a discovery would satisfy the hypotheses for a 'Planet X'
"Though the search for a distant planet in the solar system is old, it is far from over," study team member Patryk Lykawka of Kobe University in Japan told a website.
The model, created by Lykawka and Kobe University colleague Tadashi Mukai, is detailed in a recent issue of Astrophysical Journal.
The Kuiper Belt has features that can't be explained by standard solar system models. The report says one is the highly irregular orbits of some of the belt's members.
Reports say the most famous is Sedna, a rocky object located three times farther from the sun than Pluto. Sedna takes 12,000 years to travel once around the sun, and its orbit ranges from 80 to 100 astronomical units.
According to the model, Sedna and other Kuiper Belt oddities could be explained by a world 30 to 70 percent as massive as Earth orbiting between 100 AU and 200 AU from the sun, says the report.
Image: In this Caltech undated handout, a rendering of the farthest object in our solar system, Sedna, is seen; Photograph: AFP/Getty Images.
