Gravity is really an unknown force. We can define it as a field of influence, and that it effects the entire existence of the universe. Some people think that gravity consists of particles called gravitons, which travel at the speed of light. The only thing we do know is how gravity operates in different parts of our universe. Without gravity, there would be no space and time. There is a legend that says that Galileo once dropped two objects off the Leaning Tower of Pisa to show that the heavier of the two objects dropped faster. If a feather and hammer were the two objects he used then obviously the hammer would hit the ground first. T