Scientists Think They May Be Able to Find the Missing Planet Nine

• Planet Nine, the hypothetical ninth planet, may be orbiting out past Neptune, in or just past the Kuiper Belt.

• A new preprint suggests it’s possible that—if it exists—Planet Nine may have collected some moons.

• While the dark planet gives off no signals we can detect, observing the heat from those moons may be a way to finally spot Planet Nine.

There’s been a hypothesis floating around for a few years that there might be a ninth planet in our Solar System—and it’s not Pluto.
Planet Nine is unnamed, unconfirmed, and unknown. We haven’t been able to detect it, and we don’t even know for sure that if we did spot it, it would even be a planet. It might be a special kind of black hole, or be made entirely of dark matter.
But whatever it is—if it exists—we want to find it. It would explain a lot of the odd behavior astronomers detect in objects out past Neptune in the Kuiper belt. And according to a new preprint, the way to find it might be through the moons it could have scooped up over time.
Scientists Think They May Be Able to Find the Missing Planet Nine