Perpendicular velocity of planets

Hi

I am making a solar system emulation. I need some fairly precise velocities for the planets as a start velocity of the planets and since i calculate the gravity i need it perpendicular in a known distance from the sun.

First of all.. is it correct that if i calculate gravity i would only need the 'start'-velocity(perpendicular) of the planet to be able to simulate a correct path around the sun?

i have searched the web and i don't know where to find them any help?

Kasper

 PhysOrg.com astronomy news on PhysOrg.com >> Galaxy's Ring of Fire>> South Africa's new radio telescope reveals giant outbursts from binary star system>> Researchers find winds on Uranus and Neptune confined to thin atmosphere layer
 this may help although its not exactly what you're looking for: http://www.sjsu.edu/faculty/watkins/orbital.htm
 Mentor Welcome to PF, If you assume the orbits are circular, then you can figure out what the speed (which is constant) is just based on the radius. Of course, the orbits aren't circular, they're elliptical. But given key numbers for each orbit, like the eccentricity and semi-major axis, you can determine what the speed is at any point in the orbit. These numbers are what you need to model things correctly.

Perpendicular velocity of planets

Thanks for your help :)

i was missing the keyword semi-major axis ;)

 You need to find all the Keplerian elements to find perpendicular velocity: a - Semimajor e - Eccentricity i - Inclination LAN - Longitude of the Ascending Node LP - Longitude of the Perihelion ML - Mean Longitude The Anomalies - Mean, Eccentric and True You need all of these just to calculate the Radii.

 Tags emulation, gravity, solar system, velocity