# Gravity Essay

989 Words4 Pages
Gravity By Cindy Grigg | | | 1 Gravity is a force that we experience every moment of every day. Gravity is the basic force in the universe. Every body (planet, moon, star, comet, asteroid, meteor, etc.) in the solar system has a force that pulls things to itself. That's gravity- the force of attraction between all objects in the universe. 2 On Earth, it keeps people and objects from flying off into space. Gravity even keeps our air from floating off into space! An object's weight depends on the strength of the force of gravity. The pull of gravity is different on different bodies in space so weight varies on different planets or moons. For example, if you weigh 100 pounds on Earth, you would only weigh about 16 pounds on the moon. The moon is a smaller body than Earth and so its gravity is less. 3 Isaac Newton discovered in the 1600's that the force of gravity depends upon the amount of matter (mass) in bodies and the distances between the bodies. 4 The sun pulls on the Earth. The Earth pulls back on the sun. The sun is huge! If the sun were a hollow ball, you could fit one million Earths inside of it. The sun's gravity is very strong because of its large mass. However, because the sun is 93 million miles away from the Earth, the pull of gravity decreases in proportion to its distance. The Earth's gravity pulls back on the sun. The Earth stays in orbit around the sun because the forces are balanced. 5 Newton's Law of Universal Gravitation explains that an attractive force is present between any two objects. The size of the force depends on the masses of the two objects and the distance between the two objects. 6 Newton was saying that every object in the universe exerts a force on every other object. According to Newton, even your pencil and a piece of paper attract one another. You can't feel this