A membrane is stretched by a weight in the center, causing a depression that approximates a gravity well. Small balls can be put into "orbit" given the right initial velocity.
The first version pictured is quite large, a small trampoline using a 32 lb weight for the dimple.
The second version is for use on an overhead projector or a camera projection system and uses small ball bearings.
The third version is inbetween the first two in size.
Questions:
Would this work on the moon? (ie. in lower g?)
What does the central force depend on?
