It's not the first (and probably not the last) object of notable size observed beyond the Kuiper belt -- Sedna was discovered in 2003, but until now had been pretty much a lone case. Exciting as this is, it's also thought that, given certain similarities in the angle of Sedna and 2012 VP113's orbit, that there might be a much larger planet lurking in the shadows pulling on them, yet to reveal itself. This, once more, could change what we know about our very own observable solar system. Time to revise those museum models again?