Today, a set of scientists published a paper titled “Evidence for a Distant Giant Planet in the Solar System,” making the case for a ninth, as-yet-undiscovered planet. Before you get too starry-eyed, here are the key facts to know.
  1. The evidence for the giant planet was discovered in part by Mike Brown, the same astronomer who helped demote Pluto to a dwarf planet.
  2. The scientists who discovered it have been using the monickers Planet Nine, Jehoshaphat, and George. “We actually just call it Fatty when we’re talking to each other,” Mike Brown told The New Yorker.
  3. Planet Nine could be ten times bigger than Earth. It’s an icy giant with an orbit that is more elliptical than circular (otherwise known as “eccentric”).
  4. It’s far away, too. If the sun were on Fifth Avenue and Earth were one block west, Jupiter would be on the West Side Highway, Pluto would be in Montclair, New Jersey, and the new planet would be somewhere near Cleveland.
  5. While much evidence points to the existence of the planet, no one has seen it yet. If it’s as far away as scientists predict, only one or two telescopes on Earth are capable of seeing it. Brown hopes that publishing this paper will inspire more people to search for the planet. “We’re handing people a treasure map and saying, ‘Go look here.’”