I am getting stuck trying to solve a differential equation describing the gravitational relationship between two celestial bodies.
What I have so far is this:
a1 = G m2 (r2 - r1) / ||r2 - r1||^3
a2 = G m1 (r1 - r2) / ||r1 - r2||^3
where:
boldface denotes vectors in 3 dimensional...