Surface GravityThe diameter and mass of a planet combine in a very important way. They determine its surface gravity. You are very familiar with gravity. It is the the force that keeps you from flying off into space when you leap off the ground. It is the force that pulls you down on the scale when you weigh yourself. Since different planets have different diameters and different masses, the amount of gravity at each planet's surface is different. The actual relationship is pretty interesting. Greater mass means greater surface gravity. But, greater diameter means lesser surface gravity. Let's look at the surface gravity for the planets. Again, we'll base all of this an the familiar surface gravity of the Earth. | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto | | 0.39 | 0.91 | 1 | 0.38 | 2.6 | 1.1 | .88 | 1.14 | .05 | What does this mean to you? If you were standing on the surface of Mars right now, you would find that the surface gravity there is less than it is here on the Earth. That means you would weigh less on Mars than you do on Earth. (Kind of a Martian quick weight-loss plan!) To further demonstrate this effect, we are proud to introduce Your Planetary Weight Calculator. To see how much you would weigh on any of the planets, simply enter how much you weigh here on Earth. Then select the planet you would like to visit. Finally, click the Calculate button. Your weight on the planet you selected will be displayed at the bottom of the calculator.
| Intro | Diameter | Volume | Mass |
| Surface Gravity | And Beyond... | NASA Ames Educator Resource Center Content and Web Development: Brian H. Day
Responsible NASA Official: Donald James |