I just stumbled upon this problem and thought it was amazing. I don't think this problem actually requires knowledge of black holes and it seems to be a calculus problem but nonetheless I like the black hole theme. Most physics problems on Brilliant are based on classical physics and its nice to see some more problems on black holes. Check the problem out below. I'm looking forward to seeing more problems from Julian and I suggest that everyone follows him. He joined brilliant 5 days ago but the problem seems very well designed, with proper usage of LaTeX and has a nice visual. I know its hard to get your problems seen by other members with not many followers so I thought this note would be helpful.