Question: How does gravity affect the speed of light in a black hole?

AI Thread Summary
Gravity significantly influences light near a black hole, particularly at the event horizon, where light cannot escape due to extreme gravitational pull. Although photons are massless, they still follow the curvature of space-time as described by general relativity, causing their paths to bend and spiral. As light approaches the event horizon, it experiences gravitational redshift, losing energy and eventually becoming invisible. Importantly, while gravity affects the trajectory of light, it does not increase its speed beyond the speed of light, denoted as 'c.' Thus, light remains constrained to its maximum speed despite the intense gravitational forces at play.
boredjavi
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i don't know much about the subject but since I've gotten interested in it there is something that has been on my my mind.

if light would pass through the event horizon in a black hole the gravity would be to strong for it to escape. since it can't escape it would be pulled down to the point of singularity of the black hole. my question is that would the force of gravity pulling down on light be able to actually speed the light up possibly faster then the speed of light?
 
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Light is a massless particle. Though it exhibits some particle properties (duality of light), a photon has no real mass. Because of this, photons do not follow everything that particles with mass do. One of these is speeding up due to gravity. In a black hole, the photon's path with bend and spiral due to the gravity of the black hole until it reaches the center but not speed up.

The interesting thing that happens is that the photon will lose energy when going towards the event horizon and eventually become invisible once it reaches this boundary (gravitational redshift). But the photon itself will never go faster than c.
 
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thank you for that! if light doesn't have any mass how is it that it can be bent or made spiral because of gravity?
 
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Welcome to PF!

Hi boredjavi! Welcome to PF! :wink:
boredjavi said:
thank you for that! if light doesn't have any mass how is it that it can be bent or made spiral because of gravity?

In general relativity, there is no force of gravity … "gravity" is just the curvature of space-time.

Light (like everything else) follows the curvature of space-time. :smile:
 

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