Astronomers find mini-planet beyond Pluto, predict more to come

Astronomers have found a dwarf planet far beyond the orbit of Pluto, and findings suggest there could be dozens more similar, small objects – even another large planet – in the furthest reaches of our solar system.

The diminutive world, provisionally called "2012 VP 113" by the international Minor Planet Center, is estimated to be about 280 miles in diameter, less than half the size of a neighboring dwarf planet named Sedna discovered a decade ago.

The existence of the new planet was reported Wednesday in the scientific journal Nature.

“Odds are scientists will keep finding more and more of this type of world out there,” Discovery Magazine said, with scientists estimating there may be as many as 900 more such objects.

“Perhaps most intriguingly, and still fairly speculatively, the findings also suggest the presence of another large planet in the outer reaches of the solar system.”

Sedna and VP 113 are the first objects found in a region of the solar system beyond Pluto previously believed to be devoid of planetary bodies.

That zone extended from the outer edge of the Kuiper Belt, home to the dwarf planet Pluto and more than 1,000 other small icy bodies, to the comet-rich Oort Cloud, which orbits the sun some 10,000 times farther away than Earth.

"When Sedna was discovered 10 years ago it kind of redefined what we thought about the solar system," astronomer Scott Sheppard of the Carnegie Institution of Washington, D.C., said in an interview.

"These objects are not unique. There's a huge number out there," Sheppard said.

Not all of them will be visible to telescopes because they're so far away and it takes a long time for them to swing by the sun. Sedna and VP 113 were spotted at their closest approach to the sun, which allowed light from the sun to hit the objects and bounce back to observatories on Earth.

VP 113 is currently the third-farthest object in the solar system after dwarf planet Eris and Sedna, but it has an eccentric, elongated orbit that can take it out to 42 billion miles from the sun. Sedna can loop out as far as 84 billion miles from the sun at its farthest point.

Now that Sedna appears to have company — and likely lots of it — scientists are searching for more objects in an effort to learn how they and the solar system formed and evolved.

Al Jazeera and wire services