Sometimes called by it's Latin name, 'Terra', The Earth is a super computer
designed by Deep Thought, another super computer, and payed for by two pandiminsional beings Loonquawl and Phouchg. This computer was so advanced that others began calling it a 'planet', and soon life itself sprang from it's main matrices. The 'humans', 'Earthlings', etc. that were brought forth were socially adaptible, and had the amazing ability to learn from other's mistakes (and strangely enough, an apparent disinclination to do so). The 'planet' itself was mostly harmless, untill it was demolished to make way for an intergalactic bipass by Vogons (a nastly lot, them), leading to the production of Earth Mk. II, which is where we live today.
Imagine there's no such thing as a cheeseburger.
Now, imagine there's no more McDonald's.
Now, the USD is gone.
Now imagine there's no New York Times.
Good. Now, there's no New York.
Now, there's no East Coast. No West Coast.
Now, and this is the big one, imagine there's no Chuck Norris.
If you could (somehow) follow that last instruction, then the Earth being gone's easy to grasp, no?