Wrong and Stupid things what you learn from your professors at your university about Black Holes, Gravitons and Photons:

“So the virtual gravitons and photons speed away from the singularity faster than light until they're beyond the event horizon, from whence they spread out into the universe to carry on their virtual business.”

http://curious.astro.cornell.edu/physics/89-the-universe/black-holes-and-quasars/theoretical-questions/451-how-do-gravitons-escape-black-holes-to-tell-the-universe-about-their-gravity-advanced

“I am the first who understood and explained Gravitation with high speed gravitons   v = 1.001762 × 10^17 m/s, with Negative Momentum, Negative Mass and Negative Energy” Adrian Ferent

https://www.researchgate.net/publication/294087093_Ferent_Gravitation_theory