Do You Now? Gravity

Gravity is the force of fundamental interactions in nature. The space program planners continually investigate this style. Because, in the solar system and space flight, gravity is a force that plays an important role. Studies that explore the dynamics to the objects in space is called celestial mechanics. Now, knowledge of celestial mechanics allows to determine how to place a satellite in orbit around earth or to choose the correct path for sending a spacecraft to another planet.

Since the days of Ancient Greece, people have tried to explain about the solar system kinematics. Therefore, before discussing Newton's law of gravity, it helps if you also understand the thought before Newton discovered the law of gravity.

Plato (427-347 BC) Greek scientists suggested that the stars and the moon moves around the earth to form a perfect circle trajectory. Claudius Ptolemaus in the 2nd century AD also gave a similar opinion called the geocentric theory. This theory states the earth as the center of the solar system, while the other planets, the moon and the sun revolved around the earth. However, opinions of these two figures can not explain the complex movements of the planets.

Nicolaus Copernicus, a scientist from Poland, trying to find the answer is simpler than the opinions of Plato and Ptolemaus weakness. He argued that the sun as the center of planets and planetary systems of other planets including the earth round the sun. Copernicus assumption provides a solid foundation to develop views on the solar system. However, the disagreement of opinion among scientists is still there. This encouraged the scientists to gain a more thorough observation data and concrete.

Tyco Brahe (1546-1601) managed to compile data on planetary motion carefully. Data collated Tyco then studied by Johannes Keppler (1571-1630). Keppler discovered regularities of planetary motion. He said the three rules of planetary motion, now known as the law I, II, and III Kepler. Kepler's laws states:

1. All planets move in elliptical path centered on one central point (the sun).
2. Line connecting a planet to the sun will provide the same broad strokes in the same time.
3. Square of the period of each planet around the sun is proportional to the cube of the average distance of the planet to the sun.

Copernicus and Keppler legal opinions have the same style as the cause of the regularity that the motion of planets in the solar system. In 1687, Isaac Newton proves in his book "Principia" that the motion of the moon around the earth caused by the influence of a force. Without this force the moon will move straight with constant velocity. (In accordance with inertia), this force called gravity.

The force of gravity affect the movement of planets and other celestial bodies. In addition, the force of gravity is also the reason why all objects fall towards the earth's surface. Thought is the work of Newton's remarkable because it can unify the theory of mechanics and mechanics of objects on earth object in the sky. This can be seen from the explanation of free fall and planetary motion in the solar system.