Mysterious space rock Four billion years ago, Jupiter, Saturn, Uranus, and Neptune battled for position within our solar system. But some scientists suspect that there was a fifth planet, similar in size to Neptune, that was also part of the battle. Facebook Prev Article Next Article Discover Checkout these cool gadgets... Related Posts Small Planes Over Big Oceans (ETOPS Explained) What Eclipses Have Done for Science The Origins of Life..Solved? Can The Earth Run Out Of Oxygen? First major shift of human evolution What If the Earth Stopped Spinning?