Astronomers Find a Small World That Could Hint at a Big One

Move a few astronomical units over, Pluto, there’s a new dwarf in town. Astronomers have announced in Nature that they’ve discovered a new dwarf planet which, at its closest, passes about 7.2 billion miles from the sun. And what’s more, the apparent movement of this new planetoid hints that a much larger planet could be orbiting even farther out, one that could be 20x bigger than Earth.

The new body has been dubbed 2012 VP-113 and measures about 280-miles across. Circling our sun at a minimum of 80 astronomical units (1 au = the distance between the earth and the sun), 2012 VP-113 is well beyond the Kuiper belt, a thick ring of frozen bodies which orbits beyond Neptune (the farthest planet out) at 30 to 55 au away.

While 2012 VP-113 is officially way the hell out there, it’s still not as far out as the Oort cloud – a massive expanse of icy material stretching from 50,000 to 100,000 au away. To give you a sense of how far that is, a light year is equivalent to a mere 63,240 au. If the Oort cloud hurts your brain too much to think about, you can hold out hope that its existence gets debunked someday – the concept is still just a hypothesis.

Kuiper Belt IP

This diagram should give you an idea of how far away the Kuiper belt is, and how much farther the Oort cloud extends from there. (NASA)

It was long thought that the area between the Kuiper belt and the Oort cloud was entirely featureless, but this notion changed with the 2003 discovery of the 600 mile wide dwarf planet Sedna. The presence of this relatively large body in this supposedly vacant region made astronomers wonder what else might be out there. Even for super smart scientists with super powerful telescopes, seeing small stuff that’s really far away is still super hard. To spot more planetoids like Sedna they’d have to detect faint beams of light that manage to reach these distant worlds, reflect off of them, and then bounce all the way back to us. To accomplish such a feat, astronomers enlisted what has to be the most bad-ass sounding scientific instrument in the game, the Dark Energy Camera on the NOAO 4-meter telescope in Chile. Finally they spotted the faint, dim object they’ve now dubbed 2012 VP-113.

Sedna IP

Far out, man. This diagram should give you an idea of how distant Sedna (orange) and 2012 VP-113 (red) are from us – even at their closest ranges. Working outward, the purple rings represent the orbits of Jupiter, Saturn, Uranus, and Neptune, while the green dots represent the Kuiper belt, which hold the famously demoted Pluto. (Scott S. Sheppard: Carnegie Institution for Science)

Here’s what’s getting scientists (and us) really excited. Sedna and 2012 VP-113 seem to be making their tightest approach to the sun at similar angles, and this could mean that they are being affected by the gravity of a much larger body. If this planet exists, scientists suspect this giant could be up to 20x bigger than Earth. Only time – and the discovery of more dwarf planets like these – will tell if there’s a monster lurking beyond the Kuiper belt.

What do you think, Nerdist science readers?  Is there a distant mega ice planet out there affecting the orbits of Sedna and 2012 VP-2013? And more importantly, could it be Hoth!?

HT: Los Angeles Times

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