OpenEuphoria

Re: orbits

• Posted by lithex <lithex at INTERGATE.BC.CA> Oct 07, 1998
• 437 views

Lewis said
> I have my little orbitting planets program here that I've been messing
> around with lately.  After about 4 revolutions the sun runs off and
> leaves the rest of the solar system behind.  I can't find any reason for
> this so any help would be appreciated.  Also, my physics may not be
> quite right so any suggestions of how to make it more realistic would be
> considdered as well.
I think that you've rediscovered the fact that orbital systems are in
general unstable. In terms of analysis, the future trajectories of
two bodies acting under the influence of gravity only is completely predictable,
but the trajectories of three or more bodies is not predictable.

I've written gravity simulations that demonstrate the same thing as
you've discovered. No matter how finely I tuned the initial
parameters, eventually, if I had more than three objects, everything
would just go shooting out of my viewing space.

Instead of trying to simulate the solar system, I tried just putting
one hundred masses evenly spaced on a grid, and plotted their
trajectories in 2d. What happened was I started to get solar system
like features. Most of the masses would shoot off, but some would
glom together, and the gloms would start to orbit each other.

You might want to try that with your code.

Bye
Martin

or more bodies