Earth (also nick named the world) is that cool kid blue planet located under you (or on top of you, if you live at the south pole). The earth is the third planet from The Sun and actully supports life inlike its uncool younger sisters (Mercury and Venus).
Humans have known about earths existance quite literally for the whole length of their existance, there have been two main theories as to where it came from God and the other theory suggests that some complicated spacetime, dust and particles came together and exploded making The Sun and the rest of the solar system.
The earth is predicted to end on the 21st of October 2011, if not then the 21st of Decemeber 2012. Regardless of which date is correct it will look something like this: