Suppose you are in a rocket, moving very fast towards a photon that is coming directly your way. Newtonian mechanics would say that the photon would be coming at you at **more than the speed of light** (the sum of the velocity of the rocket and the photon). But we know from **relativity** that it is impossible for anyone to perceive light faster than speed of light.
What would happen to compensate for this extra velocity? Would time slow down or speed up? What would an external observer perceive of this situation if he was watching it unfold?
In: Physics
Blue shift.
Besides the covered relativity section, light is also a wave. The frequency of the waves hitting you changes the color perceived. If you’re approaching the source, things become bluer, or redder if going away. You know how trains sound different approaching vs leaving? Same thing but using sound waves.
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It turns out what you have been taught at school about adding velocities was a lie.
You can’t simply say 10 mph + 10 mph = 20 mph.
It is in fact close enough to the truth that the difference is too small to matter but if you try the same with higher velocities the difference between the simple addition and reality gets bigger and bigger.
In fact there are no two velocities that you could add together to get more than the speed of light and if you want to add two velocities together to get the speed of light one velocity already has to be the speed of light.
The way speed works is really very different from how we normally think of it and it can be hard to wrap your head around the implications even if you have the equations in front of you because it is all so counterintuitive.
if you look at the light emitted from a moving object all sorts of weird things about it will change. Things like red/blue shift. What won’t change is the speed of light.
This is because “speed of light” is really a bit of a misnomer, it is just the speed at which the universe happens. Anything that goes as fast as it is possible to go, goes at that speed including such things as gravity. Light is just the most “visible” example.
Thinking about the speed of light in the terms of everyday understanding of speed, is a bit like trying to apply your normal understanding of concepts like “going north” when you are at the north-pole.
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