↑ Has this bar ever popped up? If so, click it and Allow the content for the animations to work correctly. This bar appears if you downloaded the .zip file of the website and are viewing the pages of your computer locally.
If the LiveGraphics3D boxes on the animations just say initializing with a stellated star picture, but never actually load, you'll have to increase the amount of memory available to Java.
Note: these instructions show the boxes for my version of Windows XP, but it seems pretty similar for other operating systems. You'll need to find your Java control panel, and then find a blank box that says something like "Runtime Parameters." Click on the box, and type this in (including the '-'):
Note: This is a tricky business! You may wish to try -Xmx300m, even if you have more RAM available. If you choose too large a value, Java may fail. Also, restarting your computer may help, since Java insists on having contiguous memory allocated to itself.
Here are some screen shots of how I did it on my computer: Windows users: Click Start, go to Control Panel, and open the Java control panel.
Now click on the Java tab, and View the Java Applet Runtime Settings. When a new, small window opens up, click on the box on the right (Java Runtime Parameters), and enter -Xmx512m to increase the maximum memory for Java. Here, the 512m means 512MB. You probably shouldn't go much over half of your memory, so if you have a computer with 256MB, you won't be able to see the 3D Planetary Motion animation (I'll work on this). If you have 512MB in your computer, then type -mx256m in the box. The planetary motion animation currently needs about 250MB.