Nibiru - Sumerian name for the tenth planet. Historian Zecharia Sitchin translated 5,500 year old cuneiform clay tablets describing four planets beyond Saturn. Modern astronomers have already found three of them, the one still missing is Nibiru, which is described with a very large orbit taking about 3,600 of Earth's years to spin once around the sun. The closest it comes is about the asteroid belt, which was once a large planet until a Niburu's moon hit it.