If Planet 9 exists, it’s been through one hell of an ordeal. That’s the takeaway from a series of new studies that ask how in the name of Uranus a planet could have gotten itself into such a whacked-out orbit. This in turn might help explain the unlikely orbits of half a dozen Kuiper Belt objects.
Planet 9 is a hypothetical world roughly the mass of Neptune that orbits our Sun in a giant ellipse, at a distance of 40 to over 100 billion miles. Although astronomers have proposed hidden ninth planets for years, this latest version—the brainchild of Caltech’s Mike Brown and Konstantin Batygin—has gained quite a bit of traction since it was announced in January. The potential planet is so compelling that many astronomers have penned follow-up papers describing how we might find it and what it could look like.