A newly discovered object, Niku, is lurking beyond Neptune and is baffling scientist due to its unusual orbit.
With each new space discovery, we realize how much we still don’t know about the solar system. Astronomers recently detected a mysterious object near Neptune that doesn’t move through space as expected. The trans-Neptunian object (TNO) actually moves backwards around the sun, and it has scientists scratching their heads.
Using the Panoramic Survey Telescope and Rapid Response System 1 Survey (Pan-STARRS 1) in Hawaii, a team of astronomers discovered the mysterious object. They nicknamed the TNO “Niku”, a Chinese word for ‘rebellious.’ The movement of Niku is so weird because angular momentum generally dictates that objects in a planetary system move in the same direction. Astronomer Michele Bannister of Queens University, Belfast told New Scientist, “Angular momentum forces everything to have that one spin direction all the same way. It’s the same thing with a spinning top, every particle is spinning the same direction.”
See Also: Top 10 Fascinating Facts About Neptune
Niku has gone rogue
Except, of course, for Niku. Since the TNO is moving backwards, and also upwards, the astronomers think it must have been “knocked off course”. But we don’t yet know what exactly bumped the TNO. At first the astronomers thought the abnormal movement of Niku could be related to Planet Nine, another baffling object even further away than Neptune. But they’ve tossed that theory out for now, as Niku is “too close to the solar system” to really be influenced by Planet Nine.
Matthew Holman of the Harvard-Smithsonian Center for Astrophysics said, “It suggests that there’s more going on in the outer solar system than we’re fully aware of.”
Bannister tweeted, “I hope everyone has buckled their seatbelts because the outer solar system just got a lot weirder.”
The Wandering Niku
The little object is special in a lot of ways. First of all, it’s in retrograde. That means it’s orbiting the sun in the opposite direction of most of the other stuff in our solar system.
It also has a tremendously high inclination. What does that mean? Well, our solar system is called ‘coplanar’. All the planets revolve around the sun in the same basic two dimensional plane, like the rings around Saturn. A high inclination means an object is outside of this plane. In case of Niku, way outside the plane, moving in a “nearly polar orbit.”
But Niku isn’t alone, and that’s odd as well. The team has determined there’s likely at least a small group of similar, high inclination, retrograde and non-retrograde little objects floating around in our solar system. But what the team wasn’t able to determine is how they got there. Usually objects like this were pushed or kicked into their odd orbits when they got too close to the the gravitational pull of other objects.
But in the case of Niku and its buddies, the team ruled out all of the obvious candidates. That suggests either there’s something else out there, or that there’s something going on we don’t understand.
A group of astronomers including Holman and 16 other scientists from institutions in Taiwan, Hawaii, the UK and Germany submitted a paper earlier this month detailing the find, and it has been accepted for publication in the journal ApJ Letters.
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