Planetarion Forums

MrLobster · 5 Dec 2003, 12:41

I want to be able to display the solar system, by displaying the planets rotating around the sun. But i have looked everywhere for some formulas for this, and to no success.

Anyone got anything i can use please??

djbass · 5 Dec 2003, 13:35

You'd probably need to use formulas for calculating parabolic curves or something, though don't ask me cause I failed maths.

=[DJ Bass]=

Luckeh!!!! · 5 Dec 2003, 16:47

its not a 3d based game is it? cos that would be a little bit harder

queball · 5 Dec 2003, 19:05

An accurate model of the solar system is complicated. eg: http://scienceworld.wolfram.com/phys...dyProblem.html just describes an approximation to a simple system. You could look at using someone else's library, such as http://orsa.sourceforge.net/.

Cyp · 5 Dec 2003, 21:24

d²p_i/dt²=Σ_j≠i m_j (p_j - p_i) |p_j - p_i|³

Where p is the position of all particles in the system, and m is the mass. Probably should have some kind of units, as well.

MrLobster · 6 Dec 2003, 15:48

Quote:

Originally Posted by Cyp

d²p_i/dt²=Σ_j≠i m_j (p_j - p_i) |p_j - p_i|³

Where p is the position of all particles in the system, and m is the mass. Probably should have some kind of units, as well.

Dont want to sound ungrateful but.. what the hell??? i am not looking for an accurate model, just a basic plot around a central point, maybe using angles or something.

Radical Edward · 6 Dec 2003, 19:12

ooh simple? sinx + cosy = r

Cyp · 7 Dec 2003, 11:12

Quote:

Originally Posted by Radical Edward

ooh simple? sinx + cosy = r

Ummm, you mean {r sin t, r cos t}, don't you? Or, {r sin(ωt+φ), r cos(ωt+φ)}, if you want to control the speed and starting position. ω should be Gm/√(r³), where G is some constant, and m is the mass of the orbited object.

That should be almost correct if there is only one planet, at least.

For more interesting star systems, the more accurate model would be better, though.

Flayer · 8 Dec 2003, 17:33

Kepler: planets describe ellipse routes around the sun with the sun in one of the burning points
but this is simpler:

v = vkw( (j * M) / r )
where
j = 6,67 * 10 ^ -11
v = velocity m/s
M = mass of the sun, planet, depends which system (you want the sun's mass)
r = distant to the center of the sun
it is independent of the mass of the planet

You can transform that to get all info you need

Deathjam|wee · 12 Dec 2003, 19:23

this probaly has nothing to do with what ur on about about its ****ing cool

Deathjam|wee · 12 Dec 2003, 19:23

oops forgot the link

http://xplanet.sourceforge.net/