Once we got rid of Pluto, we thought we had our Solar System really nailed down. Turns out, there might be a new ninth planet called Tyche out there. And if real, it'd be a whopping four times the mass of Jupiter.
How could we have missed something this big? Well, the two astrophysicists who claim this thing exists say it's out in the Oort cloud, the most remote region of the Solar System. This would make it 375 times farther from the Sun than Pluto. Yep, pretty far.
Now, they're going to point some telescopes out there and see if they can't confirm that this thing exists. And then we'll have to redesign all those dioramas in science museums again.
Correction: This post originally called Tyche four times the size of Jupiter. It now correctly reflects that it's believed to be four times the mass.