The Following are excerpts from From PhET.com
Move the sun, earth, moon and space station to see how it affects their gravitational forces and orbital paths. Visualize the sizes and distances between different heavenly bodies, and turn off gravity to see what would happen without it!
Can you avoid the boulder field and land safely, just before your fuel runs out, as Neil Armstrong did in 1969? Our version of this classic video game accurately simulates the real motion of the lunar lander with the correct mass, thrust, fuel consumption rate, and lunar gravity. The real lunar lander is very hard to control. -- Note this is a Flash Simulations and requires you to enable Flash.
Build your own system of heavenly bodies and watch the gravitational ballet. With this orbit simulator, you can set initial positions, velocities, and masses of 2, 3, or 4 bodies, and then see them orbit each other. Note this is a Flash Simulations and requires you to enable Flash.
This simulator shows images of the planets at different times and locations. You ca ntarget and date show how the planets is seen on any date -- you can change UTC Field of View, and change the field of view of degree(s). Options you can change include percent of the image width -orbits -extra brightness...Frequently asked questions about this simulator.
Flash animations and simulations for astronomy education. Topics include seasons, moon phases, coordinate systems, light, and more. These animations require the flash player -- Basic Motions & Ancient Astronomy, Coordinates and Motions, Lunar Cycles, Renaissance Astronomy, Light and Spectra, Telescopes and Astronomical Equipment, Binary and Variable Stars, Milky Way Galaxy, Cosmology..... see full list.
|The Hertzsprung-Russell Diagram – A full-featured simulator for exploring the axes of the HR Diagram and the sizes of stars at various locations. It allows the user to plot the locations of the brightest stars in the sky as well as the nearest stars and answer the questions "Why are bright stars bright?" and "What is the most common type of star?".|
|Hubble's Law – A simple simulator for visualizing the expansion of the universe. Users can see vectors describing the velocities of galaxies and note that all galaxies are moving away from us. They can then change their perspective to another galaxy and note that Hubble's Law is seen from there as well.|