Hacker News new | ask | show | jobs
by ridewinter 2550 days ago
...so no time passes from the photon’s point of view.

Infinite time dilation means that a photon from a galaxy 3 billion light years away arrives here instantaneously from the photon’s perspective. Which means there’s actually no distance from the photon’s perspective - the entire universe is a singularity. Pretty mind-blowing IMO.

2 comments

That would be true if you can find a frame of reference in which the photon's velocity is 0 (its rest frame -- a pre-requisite for associating that frame of reference with the photon in the first place). But special relativity does not allow photon velocity to be zero in any frame of reference, so there is no frame of reference associated with a photon.
Is that like saying that time & distance have no meaning for a photon?
More or less.

It goes on to mean that nothing really "has a meaning" for a photon, so it's hard to really talk about a photon's perspective one way or the other. We generally just say that the photon doesn't have a perspective, i.e. that any discussion of the photon's rest frame is meaningless.

So to the degree that your question has an answer, the answer is "yes". But a better answer is that it's misleading to think that the question even has a yes-or-no answer.

Take it a step farther and the photon isn't even truly nessicary. The recoil experience when the photon was emitted, and the push felt when it is absorbed should match exactly, and essentially correspond to a single, equal, collision event to the right observer.