Model suggests 9th solar system planet

The solar system may host a ninth planet that is about 10 times bigger than Earth and orbiting far beyond Neptune, according to research published on Wednesday.

Computer simulations show that the mystery planet, nicknamed Planet Nine, if it exists, would orbit about 20 times farther away from the sun than Earth, said astronomers with the California Institute of Technology in Pasadena.

So far, the planet has not been observed directly.