The Known is finite, the unknown infinite; intellectually we stand on an islet in the midst of an illimitable ocean of inexplicability. Our business in every generation is to reclaim a little more land.  -T.H. Huxley, 1887




I wrote a sweet program that calculates the gravity on all sorts of particles and shows how they are spinning around and colliding. No real point, just cool to watch. The program simply just takes a defined number of particles, with defined mass and size. The parts are all given a random starting position and random velocity except for the largest mass which is located at the origin with zero velocity. If the particles collide during the simulation they become one, adding masses. As time passes the program calculates the net force seen on each particle from all other particles using the gravity equation. F = GMm/r^2; where G is the gravitation const, M and m are masses and r is the distance between them. Shown below is a plot of the trajectories of all the particles. (20 total)


After running the program all the individual views are compiled into a movie file. Here is an example. The blue dots are small masses, the red asterisk is the large mass. (Grav_3d.avi)


Launch in external player


You may notice that the paths are all generally elliptical or hyperbolic. This is just like reality. Some paths might seem strange but it is often due to the 3D view. Also, the interactions between the smaller masses alter the orbits slightly. Here is another example using 100 particles.