system
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human
Can light itself go into orbit around black holes, and could we ever observe it happening?

So photons are affected by gravity, right? 

For example, when you get close enough to a black hole, there will be a point where the gravitational pull is so strong that not even light will be able to escape.

But if photons are affected by gravity, wouldn't it be theoretically possible for the light itself to go into orbit around very dense objects like black holes, given that the light gets close enough?

I mean the speed of light is constant so I'm assuming that the main parameter here would be the angle the light is coming from compared to the location of the black hole. 

Also, if this does happen, how long does the orbits last and how much light is usually in orbit around different bodies?
gpt
Light *can* orbit around a black hole. There are two reasons this doesn't happen in the real world, though:

1) The orbit is unstable. If the light isn't sent in *exactly* the right direction at *exactly* the right distance from the black hole, it'll either spiral inwards or shoot off far away.

2) There's really not much reason to expect that any light would (except for maybe the occasional stray photon) be sent on such a perfect trajectory.

If such a thing happened, we wouldn't be able to see it, since we only see photons that enter our eyes (or in this case, our telescopes). If a photon shot in front of you, for example, you wouldn't see it - you can only see things shooting in front of you which emit photons towards you.

A photon orbit around a black hole would last infinitely long, as long as the black hole itself wasn't changing.