binary objects

[billybob884]

This isn't really about celestia, i know that there are binary stars and asteroids, but is it possible for a binary planet or moon to exist?

[Don. Edwards]

Ah yah!
Pluto and Charon are considered binaries. They orbit around there center of gravity.
Also the Earth and the Moon are considered a double planet system because of the moons size in comparison to its parent.

[billybob884]

Thanks!

[Thilo]

Indeed the earth does not describe a smooth ellipse around the sun, but it is also like the moon circling around the center of gravity between them ... very small only but it does. So you'll probably get a pretty wobbely movement of the earth around the sun ... only the imaginary balance point itself does this smooth ellipse :)

[billybob884]

Anyway, my second question is: is it possible to make binary planets or binary moons without having to use .3ds files? And, if so, how?

[Sum0]

Yeah, you can if you cheat a little. Just make a tiny black planet orbiting a star. Then have your binary planets orbit the black planet. Mess around with MeanAnomaly and Epoch and all that confusing stuff and you can get the planets on opposite sites of the black planet.

[billybob884]

i'd just have to make it really tiny so it wouldnt cast too much of an eclipse shadow

[billybob884]

oh and one more thing, why dont the binary stars in celestia actually orbit each other?