The eccentric orbit of a Neptune-like planet could be evidence that the distant gas giant has a smaller, rocky neighbor, astronomers say. If confirmed, the new terrestrial world will be one of the least massive exoplanets known to orbit a sunlike star and only the second known warm "super Earth." Although they are five or more times as massive as our world, super-Earths are thought to be rocky rather than gaseous—which makes them strong candidates for harboring life. More about this article from National Geographic Channel: http://news.nationalgeographic.com/news/2008/04/080411-smallest-planet.html?widgets=widgets.nationalgeographic.com|news