Mathmatics: Orbital mathmatics help please [Archive]

Wild Cobra

08-23-2009, 10:24 PM

Been so long, and I can't find the equation.

I'm looking for a formula that I can plot distance vs. time between two bodies in an elliptical orbit. Take this graphic for example:

http://upload.wikimedia.org/wikipedia/commons/0/0e/Orbit5.gif

Notice the two bodies slow down as they are farther away and speed up as they are closer to the center. If I recall correctly, I can divide them into equal area pie slices for time, but it's been more than 30 years since I used this type of knowledge.

Anyone know orbital mechanics?

travis2

08-24-2009, 06:03 AM

Look up Kepler's Laws in wiki. I think you are looking for Kepler's 1st law. It isn't given explicitly as a function of time, but in (r, theta). However, if r and theta are functions of time, that should do you fine.

I don't think you want Kepler's 2nd law...that's a 2nd order differential equation.

Wild Cobra

08-24-2009, 04:46 PM

Look up Kepler's Laws in wiki. I think you are looking for Kepler's 1st law. It isn't given explicitly as a function of time, but in (r, theta). However, if r and theta are functions of time, that should do you fine.

I don't think you want Kepler's 2nd law...that's a 2nd order differential equation.
Thank you.

That's exactly what I wanted.

Dex

08-24-2009, 04:48 PM

4 and a half.

thispego

08-24-2009, 05:13 PM

what the fuck is mathmatics

ashbeeigh

08-24-2009, 05:36 PM

and I'm having a hard time accounting for 22 missing cases in my excel file. Geez.

travis2

08-25-2009, 10:52 AM

Thank you.

That's exactly what I wanted.

No problem.

CubanSucks

08-25-2009, 04:36 PM

I'm taking college algebra:king ...for the second time