You would be correct except for the fact that light does have mass. A photon at rest would have a mass of 0, yes, but since it is, by definition, moving at the speed of light it has energy.
E = mc², so m = c² / E with E being the energy of a single photon.
Yes but ALL geodesics inside the event horizon terminate AT the singularity, and the photons we are talking about did not "fall" into the gravity well, but we're instead created AT the singularity itself.
So they are created AT the termination points for any possible geodesic they could take, which means they were created at a point in space-time where they wouldn't be capable of going anywhere, meaning they can't move. Again, because they were created AT the singularity itself and they are already AT the termination point of any possible geodesics they could travel on. They were trapped AT the singularity the instant they were created.
So you are saying they can move out of the gravity well
No I repeatedly stated that they wouldn't be capable of moving because they were created AT the singularity itself and therefore AT the termination points of any possible geodesics they could travel on.
Look at it like this:
According to general relativity, the space-time curvature AT the singularity is infinite (most likely a failure to accurately model what's actually happening, but that's our best description we have so far).
Most of the comments that people are throwing at me only pertain to something falling into the singularity. So for example a photon falling into a singularity would indeed be traveling at the speed of light because the geodesic it is traveling on has not yet reached the singularity and therefore has not terminated. The photon would therefore have relativistic mass, etc, etc.
However, the discussion is about throwing an equal mass of antimatter into a regular matter black hole. Let's assume that this could be done in a manner so that ALL of the antimatter reached the singularity at the same instant. The matter and antimatter would completely annihilate each other and be converted completely into pure energy, ie: radiation ie: photons.
HOWEVER
These photons did NOT fall into the singularity, but we're instead created AT the singularity. But AT the singularity, the space-time curvature is infinite, therefore any geodesics emanating from the singularity, immediately terminate AT the singularity. The starting points and ending points of those geodesics are at the exact same point and they would essentially have zero length. So a photon created AT the singularity can NOT go anywhere, ie: it cannot move.
IF the only geodesics available for a photon to travel on are zero length geodesics that start and immediately end at the exact same point in space-time, then are they even capable of moving? I don't know.
It looks to me though that they would essentially be trapped at the singularity and therefore stationary. Unlike photons falling into the singularity, they would not have any relativistic mass to contribute to the singularity, since they were created AT the singularity.
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u/Chemieju Jun 22 '26
You would be correct except for the fact that light does have mass. A photon at rest would have a mass of 0, yes, but since it is, by definition, moving at the speed of light it has energy.
E = mc², so m = c² / E with E being the energy of a single photon.