thinkandyouwillbecome asked: Could you explain a bit more how light is timeless and eternal? I don't quite understand! Very interesting though.
Well, part of that was just me being dramatic. But I think it’s pretty cool.
So the basic idea is this:
Time moves differently in different reference frames. For the purposes of this description, by means of Einstein’s special relativity, a reference frame is defined as constant motion that is not accelerating.
For example, a person is standing on a train platform while a train cruises by with a constant velocity (speed). Someone on the train is holding a clock that measures time using the speed at which a photon of light travels within the clock device.
The person on the platform will observe that the clock on the train is “ticking” slower than if the same observation were to be made by the person who is on the train holding the clock.
The funny thing is, neither reference frame is more correct than another. In one, time is moving at one speed. In another, time is moving at a slower speed.
Although this can be demonstrated with any clock, the reason why the example uses the speed of light is that light’s speed is never able to be changed or accelerated. Light always travels at the speed of light.
My question was, does time exist from light’s reference frame. To which the professor replied that it does not!
For example, we say the distance between two solar systems is ten light years. This means that, from our perspective observing from Earth, it would take a single photon of light ten years to travel that distance. But from the light’s perspective, that distance is crossed instantly. No time is needed.
So, for light, time does not exist. It’s fucking wild.
Pardon my physics tangent, folks. :P