Sun Earth Moon System

This simple system shows the flower-like path of a sun, earth, and moon system.  The shape of this path actually takes many by surprise.

Special Features Demonstrated:

• Trail motion

• Automatic orbit calculation

Things to try:

• Turn on the acceleration and velocity vector on the drawing pane.  I have set up the scaling so that they should be clearly visible.  It is particularly interesting to watch the moon’s velocity vector.

• The “Draw trail definition points to simulate motion” effect on the Drawing Page is very powerful for elliptical orbits because you can see how the planets speed up as they reach their closest point to the sun.  To demonstrate this, you could delete the moon from this system and lower the initial velocity of the earth (say to 200) to give it a more elliptical orbit.

• Can you get a satellite to orbit the moon (like the Apollo missions)?  This is not easy.  You’ll have to slow down the time step.  Also, think about the relative gravity wells that each body is producing.  It took me a while to get something somewhat stable.  You can download my effort here.

• Moons with different orbital planes.  These systems will produce a spiral path as the moon orbits the planet and the planet moves the planet-moon sub system through space.