Space is a big zany mystery, with astronomers discovering new stuff all the time, much of it challenging our preconceived notions of what exactly is going on out there. Even our own solar system, earth’s backyard, isn’t immune to these peculiarities.
Take Niku, for example. Niku is a recently discovered trans-Neptunian object that, frankly, seems to be defying any logical explanation. Trans-Neptunian simply means something is further from the sun than Neptune, which is pretty far away. It turns out, stuff that far away is actually kind of hard to find. When we find planets in other star systems, we do so by watching how they pass between earth and their star, which gives us an idea of how big they are as well as how far away they are. But anything past Neptune is not likely to pass between earth and the sun, so when scientists discovered Niku, it took astronomers by surprise.
Niku is weird though. For one, it’s only about 200 kilometers in diameter, which is really small on a celestial scale. But Niku it not alone, rather, it is a part of a group of objects. Of specific note, those objects are traveling around the sun “backwards,” and on a different plane than everything else we know about. A defining characteristic of solar systems has, so far, been that they accrete debris and dust around them in a ring (like Saturn but far bigger), from which planets form. Earth, Mars, and all other planets orbiting the sun are all traveling in the same direction, but Niku and its’ friends are orbiting on a plane almost perpendicular to our own.
So basically, nobody knows what’s going on here. NASA scientists have only just discovered the object, and are continuing their study of it.