For light, time doesn’t exist.


From the perspective of a ray of sunlight hitting your eye, it reaches you at the same instant it was born on the sun.

We see it taking 8 minutes to reach us, but relativity means that from the photon’s “point of view,” zero seconds have passed.

Einstein figured out that time isn’t the same for everybody.  As something (like a spacecraft) speeds up, time slows down for it.  At the actual speed of light, time doesn’t pass at all.

So if you actually reached the speed of light, you would experience no time at all until you reached your destination.

(Small problem: It’s not possible for anything that has any weight at all to reach light speed.  Light can travel at that speed because it has no mass.)

Still, it means that (at least in a sense) light is always teleporting, reaching its destination in the same moment it departed. All the light you’ve ever seen has done this.

Space movies often have people traveling faster than light.  They gloss over the fact that being able to do that would also necessarily mean being able to move backward in time.


2 thoughts on “For light, time doesn’t exist.

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