Pluto is gonna be PO'd. While the dwarf planet tries to fight its way back into the good graces of Those Who Deem What Counts as a Planet, another icy orb even further out may snatch that designation first. Astronomers at the California Institute of Technology say a giant celestial body "lurking at the end of our solar system," as the Washington Post puts it, may actually be a planet, and they're even already calling it "Planet Nine." In their research published in the Astronomical Journal, the sky-watching scientists—one of whom is known as the "Pluto killer" for his role in getting Pluto demoted—think their find is five to 10 times as massive as Earth, and per the AP, almost as big as Neptune and orbiting billions of miles past that planet's orbit. Michael "Pluto Killer" Brown and Konstantin Batygin haven't seen the supposed planet directly, but say they can infer the "massive perturber" exists by how the orbits of smaller bodies nearby are affected by its gravitational pull, the Post notes.
What's interesting is that Brown and Batygin originally set out to disprove the existence of Planet Nine. "We thought their idea was crazy," Brown says of the scientists who originally floated the idea of a large, hidden planet. But as they did their own research, they soon came to their own conclusion in what Brown calls a "jaw-dropping moment" that Planet Nine could be the real deal. Now they're simply hoping more astronomers join in to actually try to spot the alleged planet—and they're not concerned it will face Pluto's fate. "That's not even a question—it's definitely a planet," Brown says. Not everyone's convinced. "I have seen many, many such claims in my career," a planetary scientist at Colorado's Southwest Research Institute tells Nature. "And all of them have been wrong." (The Washington Post caught up with Brown for a Q&A on the latest Pluto-killing endeavor.)