Our outer solar system is a weird place that we're only just beginning to explore and understand, and now things just got even weirder.

A strange object has been discovered beyond Neptune that doesn't circle the sun on the same orbital plane as the planets do, reports New Scientist. Even more bizarre, it actually swings around the sun the "wrong" way — backwards, when compared to most other objects.

The object, a planetoid that has been named "Niku" (which means "rebellious" in Chinese), isn't just notable because of its weird 110-degree inclination orbit. It might actually hint that our solar system has more than one orbital plane, and these other planes might be teeming with mysterious planetoids hiding in places we never thought to look before.

“It suggests that there’s more going on in the outer solar system than we’re fully aware of,” said Matthew Holman at the Harvard-Smithsonian Center for Astrophysics, part of the team that discovered Niku.

Niku is estimated to be less than 200 kilometers (124 miles) in diameter. It’s actually the second object discovered that has such a retrograde orbit, after the discovery of the less-elegantly named 2008 KV42, so more uncanny worlds are probably awaiting discovery out there.

How exactly these objects have achieved their weird orbits is certainly a mystery. The reason most of the rest of the objects in our solar system all orbit on the same plane is because they presumably coalesced out of the same original star-forming gas cloud, which spun in a particular direction.

“Angular momentum forces everything to have that one spin direction all the same way,” explained Michele Bannister, an astronomer at Queens University, Belfast.

It's therefore possible that Niku and other objects like it have some other origin, though scientists can only speculate at this time.

“It’s wonderful that it’s so confusing,” said Bannister. “I’m looking forward to seeing what the theoretical analysts do once they get their hands on this one.”

Bryan Nelson ( @@brynelson ) writes about everything from environmental problems here on Earth to big questions in space.

Our solar system may have another orbital plane full of weird planetoids
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