Despite how long we’ve known Pluto existed, we know surprisingly littleaboutthe dwarf planet. For example, that photo up there? That’s theclearest image of Plutowe have, and even that is cobbled together from several shots.
This is because space is big—staggeringly, stupid, crazy big. At its absolute closest, Pluto is 4.2 billion kilometers (2.6 billion miles) away, which is a number so big that our brains don’t really know what it means. The most powerful telescopes we have only give us a grainy, out-of-focus image at that enormous of a distance.
But these images are sharp enough to tell us that Pluto is nothing like we first imagined: a boring hunk of rock. It’s surface is a carbon-rich mixture of white, black, and dark orange, and we’ve observed the poles lightening and darkening over time. Our best guess at present is that these are seasonal changes, spurred on by the distant sun that sublimates surface methane and flings it into the atmosphere (yeah, it has one of those, too).