# What is the speed of light after it has entered a black hole?

I was just thinking about this the other day. Given Einstein's Relativity etc. assigning the cosmic "speed limit" the value of $c=299792458\:\frac{m}{s}$, we know that the event horizon is the point at which not even light can escape. The acceleration due to the immense gravitational force is so great that light cannot escape. But what occurs to light on the other side of this boundary? In other words, what is the "speed limit" inside of a black hole?

• Being on one side or the other makes no difference. Which side of the event horizon of the various black holes in our universe are you on? – hft Feb 25 '15 at 21:01
• Light-like geodesics extend across the horizon; in-falling observers within the horizon measure the speed of light to be $c$. – Alfred Centauri Feb 25 '15 at 23:55