Why The Heck Is Niku Orbiting Backwards?
It's an exciting time for scientists, what with the recent discovery of a mysteriously misbehaving object in space. The object, nicknamed Niku, sticks close to Neptune — but here's the wild part: It's orbiting in the opposite direction of everything else. Obviously, everyone's got the same question: Why is Niku orbiting backwards? There are a few theories that have been tossed around, but the weirdest thing of all right now is the fact that scientists can't satisfactorily explain exactly what's going on.
To understand why Niku's orbit is so outrageous, though, first, you've got to realize that nearly everything in the universe orbits in the same direction. In a nutshell, here's why that is: Before the sun was the sun, it was a molecular cloud, which had its own rotation. The cloud started to collapse on itself to eventually form a star (the sun). Now, imagine a figure skater spinning in circles with her arms outstretched. What happens when she pulls her arms in? She speeds up! This to conserve something called angular momentum — and that's what the cloud did. As the planets were formed, they have no choice but to spin in the same direction as the star they orbit, in order to conserve momentum.
Now, there are some exceptions to the orbiting rule. For example, both Venus and Uranus orbit in different directions. Scientists have theorized that at some point in the past, they were each struck by objects large enough to knock them off course and send them flying in another direction. So, could that explain Niku? Close, but no cigar.
Niku, which less than 125 miles in diameter, is tilted at 110 degrees from the rest of the solar system and is moving upward, and scientists can't explain why. All the plausible theories floating around have been shot down — they don't make sense with what we know about the solar system — but for what it's worth, here are a few of those theories:
1. Planet Nine Is Influencing Niku's Orbit
Planet Nine is what scientists call the hidden "Super Earth" that might be orbiting the sun from very, very far away. Planet Nine could possibly have been orbiting another star when the sun "stole" it away. It's perhaps 10 times the size of Earth, and scientists have wondered if the bizarre orbit of Niku could be explained by the gravitational pull of Planet Nine.
Niku, however, is too close to our solar system to be influenced by the pull of the supposed Planet Nine. So this theory is out.
2. Nemesis Is Affecting Niku's Path
The existence of this dwarf star hasn't even been proven yet, but Nemesis — thought to be a companion to the sun — has been offered up as yet another explanation for Niku's odd behavior. Since actually don't know whether Nemesis exists yet, though... well, you can see how this theory might not necessarily hold water.
3. A Mysterious Dwarf Planet Is To Blame
A third proposed theory is that it's actually a dwarf planet (like Pluto) that's causing all this commotion. Scientists have surmised that the dwarf planet would exist in the Kuiper Belt — a disc in the solar system outside of the planets, that extends from the orbit of Neptune. The Kuiper Belt holds the three dwarf planets (Pluto, Haumea, and Makemake), and other small bodies and moons.
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