Gravitational effects are often depicted for ease of comprehension in the form of metal balls depressing impacts into a rubber sheet, usually printed with graph-paper lines to accentuated the distortion of space.
Orrerys show the relative movement of the planets in the solar system as they orbit a central sun. Combining these two results in the creation of a Rubberorrery, where the ball-like planets create appropriately sized moving dents in a suspended rubber sheet as they travel.-- xenzag, Feb 19 2016 (?) Boot to the Head! http://www.thefrantics.com/2/3 of Canada is water; we all assumed they meant rubber boots. [Sgt Teacup, Feb 19 2016] Powered by fans under the sheet providing just enough force to overcome friction and make fine adjustments to the position of planets needed due to non-ideal conditions and perturbations from outside influence. [+]-- scad mientist, Feb 19 2016 Magnets. The answer is _always_ magnets.-- MaxwellBuchanan, Feb 19 2016 I'm glad it isn't what I thought it was.-- FlyingToaster, Feb 19 2016 If it was would you have condomed the idea ?-- normzone, Feb 19 2016 My god, it's full of rubbers. No, doesn't quite work-- theircompetitor, Feb 19 2016 Bun if you incorporate rubber boots, commonly know as rubbers (No, the other kind!), perhaps painted and labelled to stand in for planets and stars.
See link for classic Canadian boot reference.-- Sgt Teacup, Feb 19 2016 That's stretching the metaphor a bit, isn't it ?-- 8th of 7, Feb 19 2016 I'll probably delete it..... in retrospect it's a crap idea. Bone is mine. Others welcome before it goes.-- xenzag, Feb 19 2016 Bone added - glad to be of assistance.
But seriously, this is not an entirely stupid idea.-- MaxwellBuchanan, Feb 19 2016 The point is it's not an entirely stupid idea.... this is what makes it crap. Who wrote it anyway?-- xenzag, Feb 19 2016 To make this satisfactory, you'd have to link the rubber-sheet mechanism to the planetary motions; that is, you'd have to make them roll round and round the big sun-depression like debris circling a drain, but without dribbling straight down into it. The engineering - especially the materials engineering of the rubber sheet and balls to have exactly the right amount of grip (approximately none), would have to be fantastically delicate. Quite likely impossible, but perhaps not provably impossible, and therefore very half-baked. [+]
[MB]'s magnets would probably help, but would be cheating.-- pertinax, Feb 19 2016 The obvious answer is to build a prototype at 1:1 scale of the original and leave out the rubber sheet until you have the mechanics sorted.-- 8th of 7, Feb 20 2016 Regular orreries CAN have arms; why can't this one?-- notexactly, Feb 20 2016 Not all of them. Sone have concentric rings with posts; others have the "planets" suspended from wires.-- 8th of 7, Feb 20 2016 Indeed; fixed. I think my point stands.-- notexactly, Feb 20 2016 Legs stand, arms stick out to the sides, points balance, so no.-- 8th of 7, Feb 20 2016 random, halfbakery