Is there a 'Minimum' Speed of Light?

  1. And would this be a candidate for DarkMatter? or Zero Point Energy?

    Tecnically if there was a Light Minimum, then this would be hard to detect, using Photons for instance.
     
  2. jcsd
  3. LURCH

    LURCH 2,514
    Science Advisor

    Not sure I understand the question, but I've read some experimients in which light has been stopped.
     
  4. russ_watters

    Staff: Mentor

    Light travels at the speed of light. Period. And speed and energy are two completely different things: those other questions are utterly meaningless. Word salad.
     

  5. E-hum!

    Feynman Fudge Factor?

    https://www.physicsforums.com/showthread.php?t=57092

    Pinch yourself and eat a little meat now and again! :wink:
     
  6. It would depend upon the reisstance it encounters, would it not?
     
  7. anti_crank

    anti_crank 131
    Science Advisor

    Real photons travel at the speed of light. Period. As for virtual photons, we can't observe them by definition, so they can in principle do anything consistent with QED.
     
  8. Lights speed is constant... it does vary in mediums though... our physics teacher talked about where he was able to run past light when he was on the outside of an experiment and light was slowed to just a few m/s
     
  9. Since light has no rest mass it is infinitely light, pardon the pun, meaning an infinitesimal amount of force is needed to accelerate it to the speed of light in the specified medium. Could you freeze a photon? Keep it still? Or would this interfere with the 3rd Law of Thermodynamics?
     
  10. To Russ Waters
    If light travels a certain distance in space in a given time, is it possible that if space were contracted, light would travel over this "shortened" distance over the same time. i.e. to an outside observer it would appear to slow down. As gravity changes space, as one approaches a black hole, light would be slowed, but never stopped. Maybe that's why black holes are black, not because light can't escape but rather that light slows down on the way in and speeds up on the way out. We just haven't yet seen the light that is slowly coming out? So maybe there are black holes that are bright also; ones that the light has escaped.
     
  11. russ_watters

    Staff: Mentor

    Well, you could measure the distance from one frame and the time from another and get a number other than C, but that doesn't really fit the definition of "speed."
     
  12. Light reaches a speed of zero all the time when it hits something.
    I think you are seeing light wrongly, it is better to see it as a ripple in space time rather than as a massed object. Light is actually an oscillating electro-magnetic field - a wave, and in lots of ways it doesn't even exist. Above all though light is energy, E = m c^2 and for light everything is on the E side, this is because it is moving at the speed of light (obviously).

    One aspect of this is that at the 'speed of light' you are at a point where time dilation is total : so to a photon time does not exist - it is destroyed the instant it is created.

    An interesting idea is that matter may be formed in the same way, as a condensate of energy - not moving outside but moving at the speed of light inside.
     
  13. If E=MC^2 and C=0 then matter could be converted into energy but the energy is not there for M*0=0 so E=0

    in reverse matter could come from nothing in a place where the speed of light is zero
     
  14. when a ball bounces off an object there is an amount of time where the ball has no speed

    now replace the ball with light, so when light hits an object light stops for an amount of time. During that amount of time matter can be created with no energy imput

    this means that matter only exist because light must bounce off of it and that light only bounces off matter that is exsiting

    this forms an continuing effect that never ends and cannot have an beginnig (at leat a beginning caused by normal energy or matter (anti or not))
     
  15. E=mc^2

    When "E=mc^2" is used, c must be the speed of ligh in a vaccume.

    Im the master at time!
     
  16. Does not C depend on where the matter chaning into energy is at.
     
  17. Interesting?..when Light is Parametrically Downconverted, say for instance at the Horizon of a Blackhole, then as you state, the process of Matter Creation is viable. Hawking Radiation is the invisible product of Light turning into Dark?..maybe?
     
    Last edited: Jan 2, 2005
  18. Photons that "hit" particles are either absorbed or ignored. They don't bounce.
     
  19. Mr. Hypermorphism, you are saying there is not a point of time where light has a speed of 0. What about at the moment that the photon is absorbed or released or ignored.
     
  20. Before the photon is absorbed, it is moving at c. A real photon released from a particle travels at c, since it is massless. The real photon doesn't accelerate from rest like a massive particle would.
     
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