4 ms·

0 time due to time dilation, but 0 distance?

12298765 8y ago
Yeah, due to length contraction
jstanley 8y ago
I think the reason it experiences 0 time is actually because of length contraction. The photon experiences the entire universe contracted to 0 length, so of course it travels along its path in 0 time.
- Retra 8y ago
  "For the photon" and "the photon's experience" are nonsense concepts. There is no such frame of reference, so it makes no sense to postulate what things would look like from it.
  - warent 8y ago
    Unless you have a better theory of spacetime and gravity than Einstein, it's safe to say frames of reference are a fundamental aspect of the nature of the universe. https://en.m.wikipedia.org/wiki/Observer_(special_relativity) https://en.m.wikipedia.org/wiki/Observer_(special_relativity...
    - Retra 8y ago
      I didn't say frames of reference don't exist, I said frames of reference don't exist for photons. I'm not sure Einstein or his theories indicate any disagreement on that point.
      - warent 8y ago
        You're right, I misread and jumped the gun. That being said, can you cite photons having no frame of reference? Not denying it to be true, but would like to know more about it.
        Retra 8y ago
        Frames of reference are identified by the objects which have zero velocity relative to them. A photon cannot have zero velocity, so there is no frame of reference for a photon. You can tell how much nonsense it is by reading the conclusions of the posters above: that 'time doesn't pass' and 'length is contracted to zero', which are just funny ways of saying spacetime doesn't exist and that's not a position any physicist will take seriously.
        pixl97 8y ago
        So if you are on planet A and want to get to planet B that is 1 lightyear away. You have a magical space ship that can accelerate to c in one minute planet A relative time. How long does it take to to planet A on the travelers watch. No copping out and saying they've been destroyed by inertia. I am going to assume it takes one year and and one minute-ish compared to synced clocks in the AB pair.
        thaumasiotes 8y ago
        > You have a magical space ship that can accelerate to c in one minute planet A relative time. > How long does it take to to planet A on the travelers watch. You're the one who discovered magic; the answer to this question depends completely on how magic works. But without magic, it is impossible for an object with mass to accelerate to c. Why do you believe the question has an answer?
        Armisael16 8y ago
        Your assumption is not supported by another current theories I’m aware of. Our physics doesn’t give any answer to that question - they throw a divide-by-zero error. The fundamental fact that led Einstein to special relativity is that light in a vacuum appears to be traveling at c regardless of the observer’s frame of reference. If the observer is a photon, however, it must be able to observe a photon traveling at 0 m/s relatice to it (is, the photon itself). This removes the cornerstone of special relativity and the whole thing comes apart. Using it to make predictions at this point is pointless. There may be a way to describe the perspective of a photon - we haven’t discovered all of physics yet - but none of our current theories do so.
czbond 8y ago
I needed some more details of how the photon experiences time, and found this (first good google result). But useful. https://medium.com/starts-with-a-bang/ask-ethan-109-how-do-photons-experience-time-94756eab8bf9 https://medium.com/starts-with-a-bang/ask-ethan-109-how-do-p...
- bookofjoe 8y ago
  "If time travel is possible, then there is no such thing as time."— Kurt Gödel

Yeah, due to length contraction

I think the reason it experiences 0 time is actually because of length contraction. The photon experiences the entire universe contracted to 0 length, so of course it travels along its path in 0 time.

Retra 8y ago
"For the photon" and "the photon's experience" are nonsense concepts. There is no such frame of reference, so it makes no sense to postulate what things would look like from it.
- warent 8y ago
  Unless you have a better theory of spacetime and gravity than Einstein, it's safe to say frames of reference are a fundamental aspect of the nature of the universe. https://en.m.wikipedia.org/wiki/Observer_(special_relativity) https://en.m.wikipedia.org/wiki/Observer_(special_relativity...
  - Retra 8y ago
    I didn't say frames of reference don't exist, I said frames of reference don't exist for photons. I'm not sure Einstein or his theories indicate any disagreement on that point.
    - warent 8y ago
      You're right, I misread and jumped the gun. That being said, can you cite photons having no frame of reference? Not denying it to be true, but would like to know more about it.
      - Retra 8y ago
        Frames of reference are identified by the objects which have zero velocity relative to them. A photon cannot have zero velocity, so there is no frame of reference for a photon. You can tell how much nonsense it is by reading the conclusions of the posters above: that 'time doesn't pass' and 'length is contracted to zero', which are just funny ways of saying spacetime doesn't exist and that's not a position any physicist will take seriously.
        pixl97 8y ago
        So if you are on planet A and want to get to planet B that is 1 lightyear away. You have a magical space ship that can accelerate to c in one minute planet A relative time. How long does it take to to planet A on the travelers watch. No copping out and saying they've been destroyed by inertia. I am going to assume it takes one year and and one minute-ish compared to synced clocks in the AB pair.
        thaumasiotes 8y ago
        > You have a magical space ship that can accelerate to c in one minute planet A relative time. > How long does it take to to planet A on the travelers watch. You're the one who discovered magic; the answer to this question depends completely on how magic works. But without magic, it is impossible for an object with mass to accelerate to c. Why do you believe the question has an answer?
        Armisael16 8y ago
        Your assumption is not supported by another current theories I’m aware of. Our physics doesn’t give any answer to that question - they throw a divide-by-zero error. The fundamental fact that led Einstein to special relativity is that light in a vacuum appears to be traveling at c regardless of the observer’s frame of reference. If the observer is a photon, however, it must be able to observe a photon traveling at 0 m/s relatice to it (is, the photon itself). This removes the cornerstone of special relativity and the whole thing comes apart. Using it to make predictions at this point is pointless. There may be a way to describe the perspective of a photon - we haven’t discovered all of physics yet - but none of our current theories do so.

czbond 8y ago

I needed some more details of how the photon experiences time, and found this (first good google result). But useful. https://medium.com/starts-with-a-bang/ask-ethan-109-how-do-photons-experience-time-94756eab8bf9 https://medium.com/starts-with-a-bang/ask-ethan-109-how-do-p...

bookofjoe 8y ago
"If time travel is possible, then there is no such thing as time."— Kurt Gödel