Gravity Essay -- essays research papers

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. This is due to air resistance, which is the force air exerts on a moving object. This force acts in the opposite direction to that of the object's motion. In the case of a falling object, air resistance pushes up as gravity pulls down, which causes the object to slow down. When Galileo's experiment was repeated on the moon, the hammer and the feather hit the ground at the exact same time. This is due to the fact that the moon has no atmosphere. Therefore, air resistance doesn't exist on the moon. Also, the amount of air resistance on an object depends on the speed, size, shape, and density of the object. The larger the surface area of the object, the greater the amount of air resistance on it. This is why feathers, leaves, and sheets of paper fall more slowly than pennies, acorns, and crumpled balls of paper. There is another legend that states that when Newton was lying against a tree in an orchard, he was struck on the head by an apple. He wondered what provided the acceleration for the apple to fall to the ground. Was this a force of the earth on the apple? If so, then the apple must exert a force on the earth according to Newton’s law of action/reaction forces. Newton applied this theory unto the planets, which orbit the sun. He found by studying astronomical data, that the force that held the earth in orbit around the sun was the same force that drew the apple toward the earth. This was the force of gravity that is given by this scary formula: F = Gm1*Gm2 gravity _______ r^2 F equals the force in Newtons, G equals the gravitational constant which is 6.67 * 10^-11 Nm^2 | kg^2, m1 and m2 equal the mass of each body in kilograms, and finally, r equals the distance between the 2 bodies in meters. If all of this i... ...for the electronic revolution of the twentieth century. Electromagnetic waves not only revolutionized our lives, but also our knowledge of the universe. Astronomers gradually opened the electromagnetic spectrum, first using visible light and then radio, x-rays and gamma rays. Each new part of the spectrum provided us with dramatic new insights into the universe. Einstein predicted gravitational waves in 1916. They have not yet been directly detected on earth, although astronomers Joe Taylor and Russell Hulse received the 1993 Nobel Prize for proof of their existence, by showing that a star system is losing energy by producing gravitational waves. Gravitational waves are a completely new spectrum. If electromagnetic waves let us see the universe, gravitational waves will let us hear the universe. They will provide us with a new sense, the sense of hearing, with which to explore the universe. Gravity is a very complicated subject, but scientists are learning more and more about it as time goes on. Contributions from people such as Newton and Einstein helped shape the way we see things today. Without them, no telling what kind of misconceptions we all might believe in today.