Backward Orbiting Planet Beyond Neptune Breaks Rules Of Solar System, Niku Can't Be Explained

In the darkness of space, way out past Neptune at the edge of the solar system, there's something really weird going on and it has astronomers scratching their heads and searching for an explanation.

Past Neptune, there's an object orbiting backwards and at an angle to the rest of the solar system, and that's really weird, Michele Bannister, Queens University astronomer, tweeted out Monday.

"I hope everyone has buckled their seatbelts because the outer solar system just got a lot weirder."
The trans-Neptunian object was spotted by the Pan-STARRS telescope in Hawaii and it's way out there; it appears 160,000 times fainter than Neptune and has been spotted at least 22 times.

Astronomers have nicknamed the object Niku, "rebellious" in Chinese, because of its strange orbit around the sun, Bannister told

"It's wonderful that it's so confusing. I'm looking forward to seeing what the theoretical analysts do once they get their hands on this one."
The trans-Neptunian object is less than 125 miles in diameter and is currently above the plane of solar system and getting higher every day; eventually it will drop and start to fall below the plane.

That's weird.

What's even stranger is that the object appears to orbit the sun backwards. Most things in the solar system rotate around the sun in the same direction, called the prograde direction, but Niku has a backwards or retrograde orbit.

The whole rest of the solar system orbits on a flat level plane; in fact that's how it formed. A star-forming gas cloud created a flat disk of dust and gas around it that came to form the planets, asteroids, and comets that populate our solar system, Bannister told LikeTheFuture.

"It's the same thing with a spinning top, every particle is spinning the same direction."
For the object to be orbiting backward it must have been knocked off course by something rather large, and that's what has scientists so interested. They've already checked to see if the backwards orbit could have been caused by Planet Nine and decided that's not the case, nor is a dwarf planet affecting it.

There are a lot of objects out past Neptune and astronomers are discovering more every day; they range from small asteroids to dwarf planets, but none of them behave like Niku.

The strange little object is orbiting at a weird angle tilted 110 degrees to the rest of the solar system, so its backwards orbit carries it both above and below the plane of our solar system. The discovery may rewrite what we know of the solar system, Matthew Holman at the Harvard-Smithsonian Center for Astrophysics told Science Alert.

"It suggests that there's more going on in the outer solar system than we're fully aware of."
Niku isn't the only object in the solar system to orbit at a weird angle, but it is very rare. Astronomers discovered a group of trans-Neptunian objects way out at the edge of the solar system in the Kuiper belt that did the same thing; that's what led them to hypothesis about Planet Nine.

Unfortunately, it's not Planet Nine that's causing little Niku to orbit in such a bizarre fashion; the object is just too close to the Sun to be affected that way, Konstantin Batygin at the California Institute of Technology told

"Whenever you have some feature that you can't explain in the outer solar system, it's immensely exciting because it's in some sense foreshadowing a new development."
The discovery is still awaiting peer review and verification, but armchair astronomers can check out the data for themselves; it's available from Cornell University as researchers take feedback before publication, astronomer Konstantin Batygin told Science Alert.
"As they say in the paper, what they have right now is a hint. If this hint develops into a complete story that would be fantastic."
What do you think is going with Niku and its weird backwards orbit around the Sun?

[Image via iStock]