Did our solar system once harbor an extra planet? (Planet X, Where Are You?)

A computer simulation has shown that our solar system couldn't have formed without an extra planet. But if that theory is true, what happened to it?

A new study based on computer simulations has demonstrated that our solarsystem might be missing a planet. In fact, without an extra planet, it seems unlikely that our solar system could have formed at all, reports PhysOrg.com.

The startling discovery suggests that Jupiter, Saturn, Uranus and Neptune were not the only gas giant planets around during the formation of our solar system. There had to be a fifth gas giant, similar to Uranus and Neptune, orbiting some 15 times further from the sun than our planet Earth.

Read More: http://www.mnn.com/earth-matters/space/stories/did-our-solar-system-once-harbor-an-extra-planet