We can't see this possible 9th planet, but we feel it

Aired: 1/22/2016 | 0:06:43 | Clip
Most of us grew up thinking there were nine planets in the solar system, but that changed when Pluto got downgraded in 2006. Now there's news that there might be a ninth planet after all. Researchers have found evidence of a planet with a mass 10 times that of Earth. Jeffrey Brown talks to Mike Brown of the California Institute of Technology.