Save fuel...use gravity! Spacecraft often use the gravity of planets to change their speed and direction. Use this Gravity Assist Simulator to explore how these maneuvers can be used to speed up, slow down, and change the trajectory of a spacecraft. Important: this simulator was designed to be used in conjunction with this activity and datasheet Invisible Collisions.

Mercury is the smallest planet in our Solar System, and is, in fact, not much larger than our Moon. How does Mercury's size compare to the other planets? Play to find out!

Since Mercury rotates exactly three times for every two orbits, a day on Mercury would be quite different from a typical Earth day. In fact, because of this 3:2 resonance, you would have daylight for 88 consecutive Earth days followed by 88 Earth days of darkness. Even more interesting is the path of the Sun as seen from the surface of Mercury around high noon. In this animation you can experience this typical Mercurian day.

Mercury travels around the Sun faster than any other planet, taking only 88 Earth days to orbit the Sun. Unlike the Earth, whose rotation on its axis takes 24 hours, Mercury takes about 59 Earth days to make complete rotation. Mercury's rotational period is exactly 2/3 of the time it takes for Mercury to complete one orbit around the Sun. In this animation you can explore this 3:2 spin-orbit resonance.

Because Mercury is the closest planet to the Sun, the Sun would appear much larger than it does on Earth. Sunrise to sunset on the planet Mercury takes 88 Earth days where the sun would appear to grow and shrink in size. In this animation you can experience a different view of the Sun.

Want to challenge yourself with some Mercurian Trivia? If so, check out the Fast Fact Challenge which contains questions about this mysterious planet.

If the first Fast Fact Challenge wasn't so challenging, test your knowledge here with more Mercurian trivia.

Analyze images of Mercury's surface to find features such as scarps, impact craters, and more in this interactive game.

In this interactive, you should build a spacecraft in order to explore the planet Mercury—just as the NASA team did when they planned and built the real MESSENGER spacecraft!