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 consists of particles called gravitons, which travel at the speed of light. The only thing we do know is how operates in different parts of our universe. Without , 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 obje ....