Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How can I calculate velocity of planet using orbit time?

  1. Mar 28, 2015 #1
    orbit-png.80293.png
    Hi. I'm just a hobbier of astronomy and have a question about elliptical orbit.
    In Before, I had calculated the elipse of a planet successfully.
    In this case, I wonder that can calculate velocity(red vector) using orbit time(or position on elipse).

    Let me assume that we know orbit's semi-major, minor axis(properties of black elipse), orbit period
    and green dot's location or elapsed time from passing perihelion or aphelion.

    I had thought that just differentiate the orbit elipse by time t but differentiate elipse is impossible operation as I know.
    so can't catch clue of this problem.

    Would anyone give me some hints?
     
  2. jcsd
  3. Mar 28, 2015 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    HInt: Kepler.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook