[Jnadke]

I suggest reading Steven Hawking's A Brief History of Time. I did so for an English paper and it was rather intriguing.

There are 4 forces associated with the atom on a quantum level, weak, strong, electromagnetic, and gravitational. On a quantum scale, the electromagnetic forces prevail. On a massive scale, the gravitational forces far outweigh the others. That's why physicists are having such a hard time these days.

Gravity is a manefestation of the trillions of atoms that make up the earth creating an equal pull on eachother, and on you. No matter where you are, you'd feel it. If you were at the center of the earth, you'd be pulled in all directions. The forces would be so strong that it would pull you apart.