Planet X, or Nibiru, is the supposed 10th planet in our solar system — if we're counting Pluto. According to the Planet X theory, Nibiru is enormous and is on a 3,600-year elliptical orbit that places it in Earth’s gravitational proximity in 2012 — an event that would cause flooding, earthquakes and worldwide destruction. Proponents of the theory cite earthquake and weather data as evidence of the planet’s increasing influence on Earth, and some say that Egyptian records show that the Planet X “flyby” corresponds to Noah’s great flood and the sinking of Atlantis.
However, astronomers say there’s no evidence to support Planet X theory and that if the planet did exist, humans would be able to see such a large planet with the naked eye. The Nibiru catastrophe was initially predicted to occur in May 2003, but the date was later changed to the infamous Dec. 21, 2012.