The below answer by Viktor Toth does not mention the Law of Phase Harmony by Louis de Broglie that explains this observer dependent variability of spacetime is inverse by quantum frequency.
That is actually (almost) correct. However, it is important to keep in mind that whether you are in freefall in a gravitational field or you accelerate, the vacuum speed of light will always remain the same as measured by you at your location.
On the other hand, in a variable gravitational field, when you look at distant clocks, they may appear to be ticking at a rate different from yours and, consequently, the speed of light at those locations will appear to be something other than the constant value to you. But to observers at those locations, the speed of light at their location will be just fine, it’s the speed of light at your location that will appear different.
I should also mention that this is one of those predictions of general relativity that can, and have been, directly confirmed by experiment. Spacecraft navigation is usually done using precision radio signals. When these radio signals pass near the Sun, they are slowed down by the Sun’s gravitational field (same thing happens near planets, but the effect is much smaller). This, so-called Shapiro delay, is an important element of precision spacecraft navigation calculations.
Finally, accelerating in empty space does indeed produce similar effects. As a matter of fact, an accelerating observer even sees an apparent event horizon (the so-called Rindler horizon) at which light, and clocks, come to a halt as seen by the observer. Unlike the event horizons of black holes, though, which are observer-independent, the Rindler horizon vanishes the moment the observer stops accelerating; and different observers do not see the same horizon.
Have you ever considered that what c is actually measuring is a duration of time or the approximate rate of change and has no bearing on the linear motion of light? If true then light may occur instantaneously in this regard, with light being a non-linear response to certain field conditions.
ReplyDeletethanks for the comment Michael. I've been reading the Quora comments on light. Momentum is actually defined by Louis de Broglie's Law of Phase Harmony but that is not taught in schools. So the momentum of light does not have traditional mass but it does have momentum based on frequency. What gets neglected -as I am just starting the very fascinating "Negative math" book by Professor Alberto A. Martinez - the simplification of Maxwell's equations by Heaviside was based on vectors getting rid of the noncommutative imaginary math of quaternions. So when we realize that frequency is actually noncommutative and nonlocal then you get a negative frequency from the future as virtual photons. Sir John Pendry and Yakir Aharonov have proven this experimentally.
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