You might think we know the solar system pretty well, but there's a lot more to our cosmic neighborhood than initially meets the eye (or telescope).
Most of the good stuff, such as the planets, moons and asteroid belt, are grouped relatively tightly toward the solar system's center and are illuminated by the sun's glare, making them somewhat easy to spot. But if you look toward the edge of the solar system, you'll find a vast, dark place in which mysterious entities can easily hide. As a result, researchers have had a field day thinking up all the things that could be lurking out there.
