Nibiru is a brown dwarf is orbits the Sun every 3700 earth years but it has a elongated elliptical orbit so it is only observed when it is near the sun which is very rare. just a few days every 3700 years.
A brown dwarf is between a star like the Sun which is a Yellow dwarf and a gas giant like Jupiter, indeed it is thought that the gas giants use to be red or brown dwarfs
A long time ago the ancient Earth was in a orbit further from the sun then it is now. when Nibiru passed through the solar system it knocked Earth nearer to the sun. that is why earth has liquid water on it. if it was where it is now the water would have evaporated in the early days when the sun was hotter.
According to ancient Sumerian mythology people from the planet Annunaki genetically engineered apes to use as slaves. These were early humans.
Annunaki is part of Nibiru's solar system of 7 planets, as a planet on its own would be too cold to support life when it is in the outer reaches of its elliptical orbit.

Some people believe the next time Nibiru passes through the solar system will be 2012 where is could ether collide with the earth or any of the planets in the solar system or the gravitational pull of Nibiru could effect the earth in some way which could cause all sorts of disasters.

In a previous blog i said the next time Nibiru would pass through the solar system would be 3700. That was because the star of Bethlehem was assumed to be Nibiru. It could be Sirius though. So I am not sure weather Nibiru will pass in 2012, 3700, or some other year.