Talk:Orbital mechanics/Archive 1

From PNA/Physics (historical)
Astrodynamics: needs to be re-written. Just throwing in names of famous scientists in history is useless. -- PFHLai 23:04, 2004 Oct 22 (UTC)


 * Yep. That's why this article has a todo list.  --Doradus 19:54, 26 September 2006 (UTC)

This article needs a lot of help
Well, folks, this is the article that taught me I'm no good at writing large articles from scratch. I'll be happy to contribute any way I can, but three years after I had first intended to revamp this article, I haven't done much. If someone else wants to give it ago, they'll have my full support. --Doradus 19:02, 19 April 2007 (UTC)

Not every one is a physicist, please write out your equations in full, like this, force = mass*distance/time squared, Newtons. Force of gravitational attraction = G*M*m/r^2, Newtons. Energy = force*distance, hence [G*M*m/r^2]*r = G*M*m/r joules. and your energy/mass = G*M/r, joules per kg. velocity v = r/t =[2*G*M/r]^1/2 = {2*[r^3/m*t^2]*M}/r, m/s, since f^2=1/t^2, then velocity, r/t = frequency*wave length = f*{r*[2*M/m]^1/2}, m/s. Since hf = mc^2, joules, then mass, m = h*f/c^2, kg, substituting for mass gives us, v=f*r[2*[h*f(M)/c^2]*[1/h*f/C^2]]^1/2, m/s. which contracts to, v=r*[2*f*f(M)]^1/2, m/s, where f(M) is the frequency of the wave between mass M and the test mass, see www.QuantumMatter.com.--79.68.156.33 23:57, 3 November 2007 (UTC)

Neat little law:
This is something about orbits I read a little while back, that might be appropriate in this article:

In order to slow down, you speed up; to speed up, you slow down.

Slowing down puts you into a lower orbit, which is faster in relation to a point on the surface of the body you are orbiting around. Speeding up puts you into a higher orbit, which is slower in relation to the aforementioned point.

Can anyone think of a place to put this?

Phædrus 12:01, 20 March 2007 (UTC)


 * I'm not sure it's that useful. It's barely even true.  If you slow down, you slow down; there's nothing magical about orbits that makes this false.  However, it is true that if you slow down at one point in an orbit, you do often end up in an orbit with a shorter period and a higher top speed, which is kind of interesting.  --Doradus 18:56, 19 April 2007 (UTC)


 * I added a "Rules of thumb" section which I hope covers this general idea in a less confusing way. -- Beland (talk) 01:49, 21 January 2008 (UTC)

Phraedrus: You are incorrect, your speed is dependent on your semi major axis and speeding up puts you in a larger orbit which means you are going slower, simple derivation from Kepler's equations.

Duplication?
Is the "Application" subsection of Kepler's Laws partly redundant with the "Position as a function of time" section of Kepler's laws of planetary motion? Not sure where this material belongs or in what form. -- Beland (talk) 19:22, 6 August 2008 (UTC)