How Astronomers Could Actually See 'Planet Nine'

On Wednesday (Jan. 20), scientists announced that a planet about 10 times more massive than Earth likely lurks in the distant outer solar system, orbiting perhaps 600 times farther from the sun than Earth does on average. "It's actually not obscenely faint," said Mike Brown of the California Institute of Technology (Caltech) in Pasadena. Brown and lead author Konstantin Batygin, also of Caltech, wrote the new paper laying out the evidence for the putative planet's existence.