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MeJennifer
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Does the speed of light for an observer falling into a black-hole remain the same?
baryon said:That is a good question, MeJenn. The answer is yes, the speed of light does remain constant for an observer who is accelerating towards a siingularity. However, there is a paradox to be dealt with. That is that the light never does reach the observer.
Isn't that just a coordinate singularity? According to the Schwarzschild metric, nothing crosses the horizon in finite coordinate time, but it does cross in finite proper time.baryon said:Here's my understanding of the subject; The light entering the black hole would never reach an observer already inside the black hole due to the infinite warping of space-time. Now the light would be red-shifted to obliviion but it still would never reach the observer. An outside observer would never see the light cross the Schwarzschild radius.
pervect said:The light does reach the infalling observer. For an observer free-falling into a Schwarzschild black hole from infinity, light from infinity will be visible to the observer crossing the event horizon and will be redshifted by a factor of 2:1.
(This was worked out in some other thread, I could dig for the details if you're really interested, but you'd need some familiarity with GR to follow the calculation).
The speed of light in an inertial frame is a fundamental physical constant that is equal to approximately 299,792,458 meters per second (m/s). This value is the same for all observers in inertial frames, regardless of their relative motion.
The speed of light in an inertial frame is considered a constant because it does not change regardless of the observer's relative motion. This was first discovered by physicist Albert Einstein in his theory of special relativity, which states that the laws of physics are the same for all observers in inertial frames.
The constant speed of light in an inertial frame has implications for time and space. According to Einstein's theory of special relativity, as an object approaches the speed of light, time will slow down and length will contract in the direction of motion. This phenomenon is known as time dilation and length contraction.
According to the laws of physics, nothing can travel faster than the speed of light in an inertial frame. This is because as an object approaches the speed of light, its mass increases exponentially, making it impossible to reach the speed of light. Therefore, the speed of light is considered to be the universal speed limit in the universe.
The speed of light in an inertial frame is measured using various methods, such as the Michelson-Morley experiment, which compares the speed of light in different directions. Other methods include using the speed of light to define the meter in the International System of Units (SI) and using the time dilation of moving particles to calculate the speed of light.