If a photon does not experience time and exists in its full trajectory at a given instant, how does it “perceive” a body moving to cut its path?

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OK maybe ELI12 would do.

In: Physics

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Anonymous 0 Comments

In this way of envisioning the universe from the point of view of the photon, “movement” does not exist because time doesn’t really have meaning. The object that intersects its path can be visualized as a 3D object smeared through the 4th dimension, and that smear at some point intersects the ray of the photon in the 4th dimension.

To make an analogy, imagine you are looking at a road that crosses a railroad line. How does the road “see the rail line move and interact with it”? It doesn’t, they exist simultaneously with a particular point of intersection.

Anonymous 0 Comments

It doesn’t perceive it. It just interacts with a body somewhere on its path. From the POV of the photon, no time has passed or will ever pass. But that doesn’t mean that every photon everywhere exists forever; from the POV of the body in its path; there was no photon at one moment, then there was a photon hitting it and being absorbed. The photon experienced no time, but the electron cloud of the body that absorbed it did.
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