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Can light be instantaneous and yet measured as 'c'?

  1. Jun 8, 2004 #1
    Hi guys,

    I am sure this little problem has been aired before.

    The postulate that 'c' is invariant from all frames of reference and the outcome of having a velocity of 'c' means contraction of space to zero.

    This would indicate that from a photons perspective space has contracted to zero thus the photons 'speed" is zero or instantaneous, and yet from a relatively stationary perspective the photon has a speed of 'c'.

    two frames of reference -
    the photons - instantaneous - zero space.
    the stationary observer - 'c' - 4 dimensional space.

    Firstly if the above is correct I DO NOT not see this as a contradiction or paradox of special relativity. If anything I see it as a strength and further validates the invariance of 'c' postulate.

    However, this pseudo paradox, seems to complicate things a little. yes?

    So I ask is 300,000 kps in a vacuum a measurement for the instantaneous?

    Could this figure 300,000 kps be a figure that could be extrapolated to a figure for time dillation experienced by the photon?

    If we work out the lorenze trandformation inversely from a position of 'c' = zero space would we arrive at 4 dimensional space?
    Last edited: Jun 8, 2004
  2. jcsd
  3. Jun 8, 2004 #2


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    If the photon had a rest frame, then its zero proper time would register there as instantanious. But the same thing that makes that so, makes a rest frame impossible for a massless object like a photon. When we look at a photon, or a beam of them, from our rest frames, they move at c. And there just isn't any rest frame where they are intantaneous.
  4. Jun 8, 2004 #3
    Why would you consider us at rest and the photon not?

    if a photon was travelling say at 0.8*'c' then would it be deemed to have rest mass?

    BY the nature of the conundrun, a photon is always in zero space but acts on 4 dimensional space.

    so really it's a question of extremes surely?

    we have reltively mass at rest ( say the earth ) and we have the other extreme of a photon at 'c' from zero to 300,000kps. just a range of extremes I would think.

    it's sort of ironical that some have posed the hypothetical that to provide the energy needed to propell an object to 'c' would take the entire universe to do so ( zero space).

    So there seems to be this "fulcrum" to relativity. 'c' being invariant in all frames of reference.

    to me it suggests that our understanding of what we are measuring when we measure 'c' needs to be expanded a little.
  5. Jun 8, 2004 #4
    unless we consider the entire universe as the rest frame.

    Why this is interesting to me is that relativity is also a theory about gravity by default..except that gravity as we normally describe it is not normally considered to have speed. ( or this is open to continuuing debate of course)

    If we accept relativity in a way that allows this photon space contraction we also have a theory for gravity.......and as I said if we expand our understanding of what we are in fact measuring with 'c' then it may extrapolate to a more universally applied theory....no more arguements etc....
    I feel that if we can reconcile this conundrum of zero space and 4 dim. space we have acheived some progress.

    I am just throwing an idea around and your comments and opinions are always welcome
  6. Jun 8, 2004 #5


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    Because there can never be an observer in the photon's frame to call at rest. What you are describing is outside Relativity's domain of applicability.
    Its not a hypothetical, its a theory. Difference? EVIDENCE. We have quite strong evidence that this is true, namely particle accelerators.
    That doesn't fit the definition of a valid rest frame.
  7. Jun 8, 2004 #6


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    "Frames of reference" are related ("transformed into each other") by Lorentz transformations. There is no Lorentz Transformation that will transform a [unit] timelike vector (representing the 4-velocity of a stationary observer) into a null [lightlike] vector (representing the 4-velocity of a photon).

    There is no "frame of reference" for a photon.
  8. Jun 8, 2004 #7
    ok ...ok...I give up.....
  9. Jun 9, 2004 #8
    Good work though Scott, you got the 'locals' well in on the action.

  10. Jun 11, 2004 #9
    Why not define c, h, G, etc. as geometric constants?

    The increase in mass of a body moving at relativistic speeds can also be interpreted as a type of rotational perspective effect, and when time is explained as a dimension, "ct", by combining one of the c's with time to convert it to a length, E = m_0 c^2 becomes m_0 c , a momentum, specifically, a momentum of an object's motion down its time axis.

    A being's conscious awareness is what is really moving along its time axis, or world- line, which is the fourth dimensional extension of its 3 dimensional self.

    m_0 c is a momentum along its time axis.

    If we stopped moving through time the rest energy of objects would be zero?


    (mc^2)^2 = (m_0 c^2) + m^2 v^2 c^2


    (mc^2)^2 - m^2 v^2 c^2 = (m_0 c^2)^2

    A hyperbolic geometry/equation of the form:

    c^2 t^2 - dx^2 = K
  11. Jun 11, 2004 #10
    good to see someone is prepared to experiment a little.....thanks Russell. Unfortunately my math ability is totally dysletic, except when it comes to money....ha....but it sure looks good.....
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