# The event horizon of a black hole supposes an absolute zero in some field?

Based on the Schwarzschild black hole theory, if the gravitational pull of the singularity were to equalize the energy that a photon has by approaching the event horizon from a special angle, would it orbit forever (Right next to the horizon) because of them having the same potential?, if true, could this be considered an absolute zero "wall"?

In the case of this being possible, if we were to see those orbiting photons, there's a chance to see images of the past?

Here's what i mean (Please forgive me for using Paint)

I'm relatively new to physics and i'm still trying to understand some things. I find it very passionating when questions like this comes to mind, so if you could help me with more certain facts about this topic it would be amazing!

• Actually, photons can orbit at 1.5 times the radius of the event horizon. This is called the photon sphere. For further info, see physics.stackexchange.com/q/25657 – PM 2Ring Nov 10 '18 at 5:01
• Amazing. So hypothetically there's a chance to detect photons that have been trapped on that sphere for some time and escaped, right? – Joaquín Herrera Nov 10 '18 at 7:16
• Hypothetically, yes, since photon sphere orbits are unstable. However, in the present era, photons that leave the sphere are more likely to fall into the black hole than to escape. That's because black holes slowly gain in mass by absorbing CMB radiation, and any stray matter in the vicinity. – PM 2Ring Nov 10 '18 at 8:13
• I found this image explaining how the photon sphere works, now i understand it but wouldn't this mean that the event horizon seems larger than its actual size? (Because of photons being unable to get out of the photon sphere if they dont have the correct angle) spiro.fisica.unipd.it/~antonell/schwarzschild/scrots/… – Joaquín Herrera Nov 10 '18 at 18:49