Results 1 to 17 of 17

Thread: Do photons experience Time?

  1. #1

    Do photons experience Time?

    Since photons are massless they can travel at the speed of light; but doesn't that mean that for them, relativistic time dilation is infinite, i.e., slowed to zero? They should be, in effect, immortal. This torpedoes the idea of red-shift changes being do to some kind of "light deterioration" that some people propose as an explanation of the acceleration of the expansion of the Universe. Photons could not deteriorate if time doesn't affect them.

    Any other ideas out there on the effect of Time on Light?

  2. #2
    Join Date
    Apr 2006
    Posts
    1,495
    Essentially you are correct. In the parlance of General Relativity light travels along null geodesics where the "norm of the tangent vector" has zero length. So you can also think of light "travelling" a path of zero length, which sounds funny but spacetime is strange like that. A more complete answer requires knowledge of differential geometry and all those good things GR is made from. (see the Wiki articles on geodesics and tangent spaces for a very brief overview)

  3. #3
    Join Date
    Jun 2008
    Posts
    3,980
    Quote Originally Posted by rreppy View Post
    Since photons are massless they can travel at the speed of light; but doesn't that mean that for them, relativistic time dilation is infinite, i.e., slowed to zero? They should be, in effect, immortal. This torpedoes the idea of red-shift changes being do to some kind of "light deterioration" that some people propose as an explanation of the acceleration of the expansion of the Universe. Photons could not deteriorate if time doesn't affect them.

    Any other ideas out there on the effect of Time on Light?
    you start out as right but then you veer off track. Not only is the time dilated distance is to. To the photon it doesn't red shift thus keeps its immortal unchanging status. Red shift is not a deterioration of light. The light isn't getting tired. It is a coordination effect.

  4. #4
    Join Date
    Mar 2008
    Posts
    5,195
    Quote Originally Posted by rreppy View Post
    Since photons are massless they can travel at the speed of light; but doesn't that mean that for them, relativistic time dilation is infinite, i.e., slowed to zero? They should be, in effect, immortal. This torpedoes the idea of red-shift changes being do to some kind of "light deterioration" that some people propose as an explanation of the acceleration of the expansion of the Universe. Photons could not deteriorate if time doesn't affect them.

    Any other ideas out there on the effect of Time on Light?
    Yes, for a photon time and distance have no meaning. We require time and distance to experience light (photons in motion). As Wayne stated red shift is a coordination effect of relative motion.

  5. #5
    Join Date
    Oct 2002
    Posts
    2,949
    rreppy,
    Where does this view come from, that "red-shift changes being do to some kind of "light deterioration" that some people propose"?
    It seems so 'counter' that I Googled for "red shift" and "light deterioration".
    The result is a near Googlewhack, as all I get is this thread, and an irrelevant reference to the treatment of sewage!

    A search without those quotes did find this article: http://adsabs.harvard.edu/full/1969Ap&SS...3..268B from which I quote;
    "Another explanation of the red shift is the 'aging' of that light ray travelling in space, as a result of which the length of the light wave increases with distance."
    Is that your source?
    But that paper is from 1968; it deals with cosmology when Big Bang still fought it out with Steady State!

    This blog http://www.a-voice.org/tidbits/time.htm refers to the argument you quote as being one used by Creationists, but the site is titled "A Voice in the Wilderness: An Oasis of Biblical Truth - For the Last Days - the Bible our Sole Authority".

    So rreppy, please show your colours. People here are keen to argue and debate from the scientific point of view, but you should declare your interest, if any.

    John

  6. #6
    Join Date
    Jun 2004
    Posts
    6,011
    Yes, I to see this as correct. That photons do not experience time..for the Photons its instant. But, but. But, My foolish mind works a little differently and, I want to explain.
    The fact that there's some thing about my wiring... Photons are sub atomic particles that are not experiencing anything at all.
    They behave as wave like particles of zero rest mass. They cover the distances of the cosmos at a velocity c. I do not know why that is. It just is.

  7. #7
    Join Date
    Jan 2005
    Location
    New Zealand
    Posts
    9,571
    As me: note that the OP states "This torpedoes the idea of...". (My underline.)

    As mod: JohnD (and everyone) please leave speculation about the motives (or whatever) of posters out of threads. Such speculation is off topic. Use the report button if you have a concern. Please stick to providing A to the Q - and if it all goes pear shaped we'll deal with it as required.
    Thank you, members of cosmoquest forum, you are a part of my life I value.

  8. #8
    Join Date
    Jun 2009
    Posts
    1,331
    Quote Originally Posted by JohnD View Post
    rreppy,
    Where does this view come from, that "red-shift changes being do to some kind of "light deterioration" that some people propose"?
    It seems so 'counter' that I Googled for "red shift" and "light deterioration".
    The result is a near Googlewhack, as all I get is this thread, and an irrelevant reference to the treatment of sewage!

    John
    You can also google "tired light".

  9. #9
    Join Date
    Oct 2001
    Posts
    29,101
    It's worth mentioning that a key part of the evidence that neutrinos have mass and therefore don't travel at the speed of light is the finding that they change types between the Sun and here. If they travelled at the speed of light, no apparent time would elapse for them, and therefore they couldn't change because for change you need time.
    Everything I need to know I learned through Googling.

  10. #10
    Join Date
    Oct 2002
    Posts
    2,949

    Cool

    Sorry.
    Citizen's arrest rarely works.
    But you mods are on the case now ('mod-handed' as it were! ) so I can leave it to you.

    JOhn

  11. #11
    Join Date
    Oct 2005
    Posts
    19,058
    It's an interesting question what it means that photon's don't experience time, and I would say it probably points to a limitation to the concept of time. I'm not convinced that light couldn't get "tired" simply because it doesn't experience time (though there are other reasons to shoot down that model), for the following reasons:
    1) light can get absorbed, and the chance of that increases with the distance the photon travels (as reckoned as distance by the absorbers, not the photon), so things can "happen" to photons even though they don't experience time-- it just means you have to also have something else involved that does experience time (the absorbers).
    2) AFAIK, electron neutrinos are still not known to have any mass, despite the fact that they participate in neutrino oscillations-- so it might just be necessary for what they oscillate into (tau and muon neutrinos) to experience time to get the phenomenon.
    3) "tired" light might have been some kind of interaction with something that does experience time (had it worked, we'd have to allow it).
    4) if our concept of time isn't working for some physical process, we don't say the process is impossible, we say either the process is impossible, or there is something the matter with our concept of time.

    Nevertheless, no "tired light" scenario has ever been made to agree with observations, as far as I know, and I don't think the OPer was suggesting otherwise.

  12. #12
    If the photon doesnt experience time, is it correct to say the age of the universe from the point of view of a phton is zero?

  13. #13
    Join Date
    Oct 2007
    Posts
    488
    If photons do not change (because they are not affected by the passage of time) how can they get red shifted while climbing out of a G well?.

  14. #14
    Join Date
    Jun 2009
    Posts
    1,331
    Quote Originally Posted by undidly View Post
    If photons do not change (because they are not affected by the passage of time) how can they get red shifted while climbing out of a G well?.
    Please see posts 2,3, etc...

  15. #15
    Join Date
    Jan 2005
    Location
    New Zealand
    Posts
    9,571
    The ATM claims by rebel have been moved to a new ATM thread ( here ).

    rebel, please do not put your personal (i.e. non-mainstream) interpretations in a Q&A thread.
    Thank you, members of cosmoquest forum, you are a part of my life I value.

  16. #16
    Join Date
    Dec 2004
    Posts
    12,199
    undidly,

    The changelessness is from the "point of view" of the photon.
    A photon never sees anything happen. Not only does a photon
    not see itself change, it never sees anything change. In fact,
    from the instant a photon is born to the instant it dies, a photon
    never "sees" anything at all. Some energy turns into a photon
    in one location and then turns into something else in a different
    location. The locations might be a nanometre apart or they
    might be billions of light years apart. Distance and time make
    no difference to the photon.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  17. #17
    Join Date
    Mar 2008
    Posts
    5,195
    Quote Originally Posted by undidly View Post
    If photons do not change (because they are not affected by the passage of time) how can they get red shifted while climbing out of a G well?.
    As Jeff stated photons themselves experience no change, in fact they cannot experience anything in a classical sense since time, distance & motion have no meaning. The red shift you talk about is only relative to the observer detecting the photon.

Similar Threads

  1. [Photons are affected by time]
    By rebel in forum Against the Mainstream
    Replies: 80
    Last Post: 2010-Jun-22, 04:12 AM
  2. My Moving Experience
    By BigDon in forum Off-Topic Babbling
    Replies: 10
    Last Post: 2010-Feb-21, 02:57 AM
  3. In what ways, if any, do photons differ from virtual photons?
    By AndrewJ in forum Space/Astronomy Questions and Answers
    Replies: 25
    Last Post: 2009-Feb-18, 06:50 PM
  4. Time to Experience Black Holes
    By Maddad in forum Astronomy
    Replies: 8
    Last Post: 2005-Aug-18, 04:28 PM
  5. Replies: 9
    Last Post: 2005-Jun-29, 04:30 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
here
The forum is sponsored in-part by: