Build your own Solar System..

[Jonathan in Hiram]

Kind of fun, this site lets you build your own solar system by dragging and dropping.

Play with it for a little while and it gives you a feel for how chaotic orbital dynamics can be, put a gas giant in close to the sun with a small world outside and watch it get sucked in unless it's a long way out.

Binary star systems don't have planets close either for more than a few orbits.

http://www.alienearths.org/online/interactives/planet_families/index.php

 

[spinningmagnets]

Ever heard of Immanuel Velikovski? He had some controversial theories concerning planetary movements in historic times (oral histories).

 

[Jonathan in Hiram]

Oh yes, I read "Worlds In Collision" while I was still in grammar school, when I asked some of the adult astronomers in the club I belonged to it about it, it took them a while to regain their composure and wipe the tears from their eyes. I then had the difference between open minded and empty headed explained to me at some length.

There used to be an Atari arcade game I played from time to time called "Gravitar" that involved orbit dynamics..

http://en.wikipedia.org/wiki/Gravitar

Orbit dynamics is strongly counterintutitive, you slow down to drop into a lower orbit, which then speeds you up.

There are actually quite a few orbital simulators out and I've played with a number of them.

http://orbit.medphys.ucl.ac.uk/

http://www.orbitsimulator.com/gravity/articles/what.html

http://www.arachnoid.com/gravitation/big.html