As I understand it, when an object is traveling at the speed of light, relative to itself all travel is instantaneous and the distance is zero. If a photon traveling from the sun was aligned with the Earth and Mars is the trip to Mars literally the same as the trip to Earth. I'm trying to picture how that works - are Earth and Mars and the rest of the universe for that matter condensed to a single point relative to the photon?
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Qmechanic
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Jesse Adam
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1take a look on this answer: http://physics.stackexchange.com/a/190056/73635 – aaaaa says reinstate Monica Jun 18 '15 at 16:47
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3There is no reference frame for a photon, so trying to picture it is ultimately futile. – Kyle Kanos Jun 18 '15 at 18:49
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Oh, you can conceptualize it as the limit of every increasing boost. It's just that the limit is non-physical: things that can be luminal must be and those that can be non-luminal will always be. – dmckee --- ex-moderator kitten Jun 18 '15 at 20:08
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1While there is no rest frame for photons, both the distance and the time it takes to traverse that distance are clearly physically "counted" by the number of wavelengths that fit between both points. That number is Lorentz invariant and therefor a relevant physical quantity in all reference frames. – CuriousOne Jun 19 '15 at 00:35
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"traveling at the speed of light relative to itself" ...??? – WillO Feb 01 '21 at 13:18
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You are asking us for the distance of the trip in the rest frame of the photon. The problem with asking that is that there is no rest frame of a photon. A photon can never be at rest, so it has no rest frame. This is like asking what a bowl of petunias thinks about its existence as it falls to the surface. A bowl of petunias doesn't think, therefore we can't tell you what its existential thoughts are. Similarly, a photon has no rest frame, therefore we can't tell you what distances become relative to it
Jim
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2Nevertheless, it is possible to define the infinite momentum frame via the limiting procedure. And indeed, in this frame space becomes effectively 2-dimensional. This fact is used in string theory, for example (in so-called light-cone gauge). – Prof. Legolasov Jun 18 '15 at 20:01
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Since the light "counts" wavelengths, the question is actually meaningfully answered by nature, even though the way it's expressed in the theory is not quite as obvious. – CuriousOne Jun 19 '15 at 00:37
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I think a better way of saying this question would be, "Can we assign an intrinsic clock to each photon "particle" which happens to stop working as "seen" by any other everyday clock"? Or don't you think that for such photons ALL distances (as "seen" by them) are shrunk to zero so that they feel to be present at ALL places simultaneously? If not, why not?" – Benjamin Mar 24 '16 at 23:05