nightowl

lmfaotrololol I had no idea gnuplot can do that. 10x!

Greetings everyone! I've decided recently to build a fortran code that integrates the newtonian two-body problem, just to have some fun, and I was wondering, do you know of any software, maybe similar to gnuplot, that could read the output file but instead of simply drawing a plot, creating an actual animation of the motion? I know Mathematica had some facilities similar to this but: 1. I don't really like canned software. 2. The Kepler equation doesn't have (at least to my knowledge) an analytical solution so it's not as easy as just inserting the law of motion as a function of time in mathematica and let it make the movie. So what I'd like would be a text based program that can read a datafile and make an animation with the numbers it reads there. Thanks!

Greetings everyone! As the title says, I'm having trouble in solving this problem. For a system formed of a stationary electric pole and a stationary magnetic pole, the electromagnetic angular momentum is independent of their separation distance. I've managed to prove this (and calculate the angular momentum explicitly) but I'm having trouble in answering another question, namely to prove that the electromagnetic linear momentum density has 0 divergence by writing it as a curl. It is easy to calculate the divergence explicitly, but I have no idea how to find the vector having as curl the linear momentum density. Right now I'm mostly trying various quantities, my best result reproduced the linear momentum density but multiplied by a non-constant factor so the answer must be wrong. Any tips would really be appreciated, it's really bugging me. Thank you!