Somewhat inspired by "Dog Orrery". The discussions therein made it clear that ordinary orreries lack astronomical verisimilitude, operating as they do with circular orbits in a single plane.

So.

The MaxCo Proper Copper Orrery Company of Oregon (currently seeking venture capital and, indeed, a potential customer) is working on a scheme to create an actual-reality orrery in orbit.

We are starting with a one-ton sun, which will of course be painted yellow as it is meant to be. This will be put into orbit in a quiet part of the solar system, as free as possible from the gravitational tugs of real planets. (By keeping the whole thing fairly small, we hope to minimize tidal forces.)

The planets will be made to scale in both size and mass (using various combinations of lead, copper and aerospace-grade papier mache), and each will be tenderly launched on an orbit around the sun, assuming a start-date of Jan04 1643, midnight GMT.

Setting the scale-moons (each individually carved by former jewellers) on precisely the right courses will be phenomenally difficult, but we are working on that, and are 100% confident that we might succeed.

We haven't entirely solved the problems associated with Saturn, and we aren't even thinking about the rings around Uranus yet, but rest assured that a solution will be found.

The fleet-minded amongst you will have realized that, with a 1- ton sun, and with distances to scale, the speed of the orrery will be....well, OK, no point stating the obvious, I know.

[STOP PRESS: The technicians at The MaxCo Proper Copper Orrery Company of Oregon have just woken up to the principle of reversibility. We have therefore decided to set everything moving in a retrograde manner, so that the Proper Copper Orrery will, in fact, recapitulate the past history of the solar system, running backwards from 1643.]
-- MaxwellBuchanan, Feb 16 2010

Scaling the Orrery: If the Sun was the size of a bowling ball... http://www.noao.edu...eppercorn_Main.html
If the Sun was the size of an 8" bowling ball, the Earth would be the size of a peppercorn, and Pluto would be smaller than a pinhead. To make a model of the solar system to scale at these sizes Pluto's pinhead would be located over half a mile from Sol's bowling ball. [jurist, Feb 17 2010]

//former jewellers// former?
-- mouseposture, Feb 17 2010


//We are starting with a one-ton sun...// Surely you don't expect us to pay the freight on that. And which western state are you co-opting in order to present your scale model before the actual launch? It will be about the size of Colorado, won't it?
-- jurist, Feb 17 2010


So, not just a Laboratorrery demonstration?

+ for "astronomical verisimilitude"
-- csea, Feb 17 2010


+ for //aerospace-grade papier mache//
-- coprocephalous, Feb 17 2010


In order to truly scale, and to reproduce the gravitational forces present in the real system, wouldn't you need to drastically increase the densities of your planetary bodies? Loads of maths here, if the Earth has a density of 1, and you plan to scrink its radius by a factor of 100 million, and if density = mass/volume, and volume of a sphere is 4/3 pi r³ - then you need to determine the forces exerted due to gravity based on mass and distance.

I think you might need more sophisticated materials than lead, copper etc (guessing here that by creating a "fun" sized solar system, we need to increase the densities of our resultant bodies)
-- zen_tom, Feb 17 2010


This depends on how fast you want your orrery to orrerate.

And a [*] for "laboratorrery demonstration".
-- MaxwellBuchanan, Feb 17 2010


I'm still a little tired from a late night battling with servers, so help me out with the math here...If the sun is dropped to only a ton then to get the system to work you need to scale not to the size fraction, but the mass fraction. Since lead has 8 times the density of the sun, a solid lead sun will scale down the orbital dimensions with the mass fractions. Or were you going to make the bodies hollow.
-- MisterQED, Feb 17 2010



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