Xena, unofficially called the 10th planet, is the second-most-shiny known object in the solar system, new observations show. Scientists are scrambling to explain where Xena got its sparkle. Some suggest that it might have enough heat to belch methane, despite being in the coldest region of the solar system.
The new notion of Xena arises from Hubble Space Telescope images that were released this week. The images reveal that Xena, the most distant known object in our solar system, isn't quite the big shot that scientists had thought it was.