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The solar system; why planets orbit.


katrina27

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We look up in the night sky to see stars and the moon, we don't think much of it. But there is so much about our solar system that we don't know. Our solar system can be defined as a star and all the objects orbiting it as well as all the material in that system. Our solar system includes the sun together with the eight planets and their moons as well as all other celestial bodies that orbit the sun.

Ancient astronomers observed light that appeared to move among the stars. They called these objects "planets," meaning wanderers. Then named them after Roman deities—Jupiter, king of the gods; Mars, the god of war; Mercury, messenger of the gods; Venus, the goddess of love and beauty, and Saturn, father of Jupiter and god of agriculture.

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But what does this all mean? There is no force that causes the planets to rotate. Most of the rotation comes about from the conservation of angular momentum. In the case of orbital motion, the counteracting force is gravity; gravity causes the body to continually fall towards the center, and this exactly counteracts the force resulting from the centripetal acceleration. This results in a limit for how fast an object can rotate and still keep itself together. If it rotates too fast, the outward acceleration felt by the elements in the body may be more than the force that keeps them bonded together, and if this happens, the body breaks up.is that the gravity of the sun keeps them in their orbits. Just as the moon orbits the earth because of the pull of earth's gravity, the earth orbits the sun because of the pull of the sun's gravity.

To put it simply, the reason planets rotate around the sun is that the gravity of the sun keeps them in their orbits. Just as the moon orbits the earth because of the pull of earth's gravity, the earth orbits the sun because of the pull of the sun's gravity. Why does it travel in an elliptical orbit around the sun? This happens because the earth has a velocity in the direction perpendicular to the force of the sun's pull. If the sun weren't there, the earth would travel in a straight line. But the gravity of the sun alters its course, causing it to travel around the sun, in a shape very near to a circle. We have a stable orbit which allows us to not get too close or too far from the sun.

One physicist who made laws about planets was Kepler who said;

The path of the planets about the sun is elliptical in shape, with the center of the sun being located at one focus. (The Law of Ellipses)

An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time. (The Law of Equal Areas)

The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun. (The Law of Harmonies)

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