Our revised larger size for 2007 OR10 makes it increasingly likely the planet is covered in volatile ices of methane, carbon monoxide and nitrogen, which would be easily lost to space by a smaller object," said András Pál at Konkoly Observatory in Budapest, Hungary, who led the research. "It's thrilling to tease out details like this about a distant, new world -- especially since it has such an exceptionally dark and reddish surface for its size.