This applet is an interactive exhibit simulation of the effect gravity has on a moving object in outer space.
To try this
simulation:
First left-click and hold to place a red ball on to the well surface. Release the button and drag to determine the direction and speed (velocity) of the ball. The length of the arrow will correspond to its initial speed. Now left click again to start the ball.
What's Going On?
The Gravity Well can simulate the effects of gravity on a satellite. As a ball rolls closer to the center, the sides get steeper. This causes the ball to speed up because gravity is pulling the ball down a steeper incline.
There's More!
In space, moving closer to the object being orbited will cause the satellite to speed up. When the satellite (or ball) speeds up, it gains momentum, which is a tendency to keep going in the same direction. If the satellite is moving pretty fast and not quite aimed directly at the orbited object or center of the table, the momentum will try to carry it past the object.
As the satellite travels past, gravity will tend to pull it towards the center of the orbited object, curving the satellite's path. If you can manage to balance the momentum of the satellite and the pull of gravity from the orbited object, you can make the satellite "fall" around the object.
If the satellite is traveling too fast, the effects of gravity will not curve the path enough and the satellite will zoom right past. If the satellite is traveling too slowly, the path will curve dramatically and the satellite will crash!
The Moon is a satellite that balances momentum and speed. The Moon is continually falling around the earth in an elliptical orbit.
