Another force that you experience every day is gravity. Gravity acts between all particles that have mass. The more mass an object has, the stronger the force of gravity. You may think that the effect of gravity holding you down is strong, but the force of gravity is actually the weakest of the four forces.

Gravity is responsible for the orbits of planets, moons, and satellites, the large-scale structure of the Universe, and the motion of other objects in space. Gravity has an infinite range but gets weaker and weaker as the distance gets bigger. The moon's gravity is pulling on Earth all the time. Since gravity depends on distance, the moon pulls stronger on the near side of Earth than it does on the far side. This effect creates deeper and shallower areas in the oceans, and this is responsible for the tides.

Gravity is best described by the field theory, but scientists have formulated a way to describe it using a force carrier called the graviton. Scientists know a lot about what the characteristics of a graviton would have to be, but no one has ever seen one.

Exploring the History of Gravitational Force

Now that you have had an opportunity to review, let’s explore the history of gravitational forces. Click on the following link to learn more about the history of gravity: History of Gravitational Forces. As you read, create a timeline in your notes.

Now let’s take a moment to look more closely at the connection between Newton and Einstein. Watch the following video explaining this connection.