Astronomers have discovered an object in our solar system that is larger than Pluto. They are calling it the 10th planet, but already that claim is contested.
It is the first time an object so big has been found in our solar system since the discovery of Pluto 75 years ago.
The announcement came just hours after another newfound object, one slightly smaller than Pluto, was revealed. The new object, temporarily named 2003 UB313, is about three times as far from the Sun as is Pluto.