Fifth planet (hypothetical) orbit as defined by the Titius–Bode law. Between 1845 and 1851, eleven additional asteroids were discovered and Jupiter had become the twentieth planet. At this point, astronomers began to classify asteroids as minor planets. Following the reclassification of the asteroids in their own group, Jupiter became the fifth planet once again. With the redefinition of the term "planet" in 2006, Ceres is now considered a dwarf planet. The disruption theory suggests that a planet which was positioned between Mars and Jupiter was destroyed, resulting in the asteroid belt between these planets. Scientists in the 20th century dubbed this hypothetical planet
Escape from the Planet of the Robot Monsters a robot army to take over the Earth. "Escape From The Planet Of The Robot Monsters" is a one or two-player game in which the players must rescue Dr. Sarah Bellum from Planet X, where her research facility has been taken over by the evil Reptilons. The game is played from an isometric perspective where players control their avatars using Hall effect joysticks on the arcade version. The player must shoot their way through a series of simple maze-like levels, releasing the human hostages along the way. Levers must be found and thrown to activate the escalators which allow access