The idea of planet X, and the search for the elusive planet, started in the middle of the 19th century after Neptune was discovered, since many astronomers believed there was another planet beyond Neptune’s orbit. In the early 1900’s, the famous astronomer Percival Lowell searched for planet X and claimed that this mysterious planet was the reason why there were discrepancies in the orbits of the gas giants in our Solar System. When Clyde Tombaugh discovered Pluto in 1930, it was believed to be planet X, confirming the hypotheses of Percival Lowell and many other astronomers. However, in 1978, astronomers discovered that Pluto could not be planet X because it was too small to affect the orbits of the gas giants.

After this discovery, some astronomers continued to look for planet X. Robert Harrington was one astronomer who continued the quest throughout the 80’s and 90’s. By the time of his death in 1993, he had not found planet X. A number of other scientists, including Joseph Brady, proposed their own theories regarding planet X. Just a few months before Harrington’s death, the astronomer Myles Standish calculated Neptune’s mass with the Voyager 2 probe. When calculations were done with this revised mass, the discrepancies regarding Uranus’ orbit disappeared. This led scientists to conclude that no planet X, at least Percival Lowell’s version, exists.

According to the 2012 doomsday theory, Planet X would crash into Earth and destroy all life. To further complicate matters, some people who believe in 2012 have also linked planet X as being the same as Nibiru. The Nibiru theory says that an alien race came to Earth on the planet Nibiru thousands of years ago and genetically altered beings into humans in order to serve them. Nibiru is supposed to return in 2012 to cause havoc and destruction. So, there is no Planet X, and the world is not ending on December 21st, 2012.