Planet orbital location database

[krsbuilt]

I wrote a program in java to simulate gravity in 3 dimensional space between any number of objects, and i wanted to test if it works. i managed to find the data for the Earth and the sun and tried those out and the sun acted as a slingshot for the earth. i would like to know if i could find some sort of database containing the current position in space for all the planets at any particular time, so that i may plug those into my simulator and try to get out a decant simulation. does anyone know of a database that is free to use that would get me the current orbital velocities and coordinates of all the planets?

 

[krsbuilt]

ah, yes. i should probably mention that my suspected reason for the Earth not rotating properly is that the sun is not a fixed body, i noticed that the sun is actually moving towards the earth. so i need the rest of the system to minimize the suns movement, therefore hopefully removing the slingshot effect.

 

[zhermes]

Nasa JPL maintains just such a database, see: http://ssd.jpl.nasa.gov/?ephemerides.

Including the other planets won't fix your problem however. There is something wrong with your equations or initial conditions--are you sure you included the proper initial velocities?

 

[krsbuilt]

ok, i figured it out. i kept on adding to the acceleration due to gravity to the previously calculated acceleration. rookie mistake. the database will be useful still. anyways, I'm not sure about with all the other planets, but with just the Earth orbiting the sun, the Earth actually pulls the sun. the direction it pulls is determined by where the Earth started its orbit. it's interesting actually.

 

[tony873004]

Zhermes gave you the best answer. Use JPL Horizons. Here's some solar system data for a simulation I made. I got this data from Horizons. Everything is given relative to the Sun, so the Sun's position is 0,0,0 and its velocity is 0,0,0. The first 3 numbers for each object are position: x,y,z. The last 3 numbers for each object are velocity: x,y,z. These numbers are for May 29, 2011 at 00:00:01.

2011 05 29   00 00 01	Sun	0	0	0	0	0	0		Mercury	53415407007	-3258938251	-5167464455	-6446.040768	50804.60764	4742.469441		Venus	1.04688E+11	28059179722	-5657450542	-9189.841943	33670.99928	991.6719595		Earth	-58865713781	-1.39717E+11	3639009.381	26971.8094	-11689.08266	0.816775593		Mars	1.91314E+11	93944499293	-2729265145	-9753.30586	23819.54731	738.605914		Jupiter Barycenter	6.90637E+11	2.66618E+11	-16562275828	-4869.216238	12821.93657	55.72581332		Saturn Barycenter	-1.38668E+12	-3.85124E+11	61902274937	2060.483788	-9318.279905	80.17792789		Uranus Barycenter	3.00382E+12	58703701573	-38692419910	-186.6851099	6501.31934	26.5613355		Neptune Barycenter	3.8412E+12	-2.32328E+12	-40667374961	2773.352923	4692.851413	-160.3628824		Moon	-58496211597	-1.39558E+11	35681113.77	26572.65663	-10802.40349	-45.08250411		1 Ceres	3.90097E+11	-2.02397E+11	-78200297604	7465.522727	14741.43173	-915.5766609		10 Hygiea	-2.33765E+11	-3.42164E+11	-20595370850	15581.16114	-10660.42018	851.3753685		16 Psyche	-1.72758E+11	3.99025E+11	-14132409418	-16859.4099	-4653.379158	671.1802206		2 Pallas	1.98797E+11	-3.91685E+11	2.54128E+11	13374.70534	3442.137112	-3492.811903		3 Juno	-4.40076E+11	-43364871018	27613130497	-2032.371106	-15791.11996	3666.075452		4 Vesta	1.20474E+11	-3.04625E+11	-5475194949	19582.77003	6655.997887	-2579.539478

 

[zhermes]

ok, i figured it out. i kept on adding to the acceleration due to gravity to the previously calculated acceleration. rookie mistake. the database will be useful still. anyways, I'm not sure about with all the other planets, but with just the Earth orbiting the sun, the Earth actually pulls the sun. the direction it pulls is determined by where the Earth started its orbit. it's interesting actually.

The motion of the sun should be 1) barely noticeable (displacement relative to the semi-major axis should be about the same as Earth's mass relative to the reduced mass), 2) elliptical 3) always opposite the COM from the earth, and with a velocity opposite in direction, and with a magnitude such that the total momentum in the COM is always zero.