Take the 2-minute tour ×  I'm not very knowledgeable about
physics generally, but know that nothing can escape a black
hole's gravitational pull, not even light (making them nearly
invisible?).  My question is: What has been obtained from direct
observation of a black hole to prove their existence? Please
note that I'm not questioning the existence of black holes, but
am just curious as to how we have come to realize it.
share|improve this question Feel free to criticize/pick
apart/edit my question. –  LanceLafontaine Jun 7 '12 at 19:52
This 2007 paper seems relevant: arxiv.org/abs/astro-ph/0701228
–  Qmechanic Aug 17 '12 at 17:46  3 Answers 3  up vote 18 down
vote accepted   Scientists assume that black holes exist based
mainly on the predictions of general relativity. In particular,
general relativity tells us that if an amount of mass $M$ is
contained in a spherical volume of radius $r_s =
\frac{2GM}{c^2}$, space will be warped so drastically that all
possible paths within that sphere lead inward toward t