Why do massless particles not experience time?
In: Physics
With relativity you have to think about space and time as a unified whole, not two separate phenomina. And, more surprisingly, we are all moving through spacetime at the same speed: the “speed of light” *c*. Objects moving extremely fast through space experience less time, and objects which are moving slowly experience time more “normally”. But, regardless, if you move fast in one you move slowly in the other but the total magnitude of your velocity through spacetime is always *c*.
Now, apply that concept to a massless particle like a photon: It has no mass so it moves through space at speed *c*, but that means there’s nothing left in it’s velocity vector for it to travel through time.
For further reading:
[https://medium.com/predict/we-all-travel-through-spacetime-at-the-speed-of-light-d60cb389dfc2](https://medium.com/predict/we-all-travel-through-spacetime-at-the-speed-of-light-d60cb389dfc2)
[https://physics.stackexchange.com/questions/33840/why-are-objects-at-rest-in-motion-through-spacetime-at-the-speed-of-light](https://physics.stackexchange.com/questions/33840/why-are-objects-at-rest-in-motion-through-spacetime-at-the-speed-of-light)
[https://www.quora.com/Does-everything-travel-at-the-speed-of-light-in-spacetime](https://www.quora.com/Does-everything-travel-at-the-speed-of-light-in-spacetime)
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