NASA announced today that its Wide-Field Infrared Survey Explorer (WISE) was unable to find "Planet X," a hypothetical, large celestial body that some scientists theorize might exist somewhere beyond Pluto. On the plus side, WISE did locate thousands new stars and brown dwarfs, so it wasn't a total waste of staring into space.
According to Kevin Luhman, who authored a paper discussing the WISE data, it's time to put dreams of Planet X to rest. "The outer solar system does not contain a large gas giant planet, or a small companion star," he said. WISE scanned the sky in infrared light but did not find an object fitting the description of Planet X — at least the size of Saturn within 10,000 astronomical units or one at least the size of Pluto within 26,000 astronomical units.
Some scientists had hypothesized the existence of Planet X (also nicknamed "Nemesis" and "Tych") to explain the odd orbit of small, icy objects identified by astronomers. Back in 2012, researcher Rodney Gomes said that a Planet X would exert gravitational pull on objects past Neptune, and explain why they travel the way they do. Now, scientist will have to develop another theory to explain the erratic movement of such objects.