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I agree LeeE; a Doppler shifted photon has not lost energy; I was thinking of things that might actually reduce the energy of a photon.
Quote from: Vern on 06/02/2009 13:29:37I agree LeeE; a Doppler shifted photon has not lost energy; I was thinking of things that might actually reduce the energy of a photon.It has lost energy in as far as it can't transfer as much energy to what it hits as when it left home.
I don't understand this answer relating to referential frames. The photon has less energy now than it one did, if I measure it. So where is that missing energy?Chris
Vern, if you look at it as a wave instead of particles then where are the (light quanta's) 'energy' placed?
But I would like to see a 'main stream' view too.Is there anyone who would like to describe red and blue shift.
There are arguments against 'tired light' that makes sense to me, one need to see that some build on other main stream assumptions though, but they all seem to fit together. I have this link http://www.astro.ucla.edu/~wright/tiredlit.htm that discuss some of the arguments against.
I received an email from the Naked Scientists today informing me that they put my question on this forum on my behalf and I am glad that they did. So I joined the forum and I read through all of the responses in this thread about five times because it took me several times to either figure out what each comment meant or to formulate what it is that I donít understand and of course to come up with additional questions. I would like to thank all those that responded to this question and to all those that may respond to my additional questions. I really do appreciate it. Here is a summary of some clarifications, things I understand and what still puzzles me.1) Conservation of energy applies to this photon. Energy is neither created nor destroyed.2) The perceived loss of energy is due to the fact we are moving in a reference frame relative to the reference frame the photon was emitted in. If I was in a rocket ship traveling toward the photon as it reached earth and my speed was very high I would perceive this photon blue shifted and at a higher energy than if I was standing on earth. So energy is not the same in two reference frames. This must be similar to length of an object or the passage of time not being the same in two reference frames. 3) Does the original reference frame still exist? If so, where is it? How far is it from us? How fast is it moving away from us? Is it accelerating away from us? What has the relative velocity between these two reference frames been as a function of time? t = 0 to t = 13.3 billion years. Can this be calculated using the Hubble constant and the distance of 13.3 billion light years? If so how is this calculation made? When I tried this I came up with an answer that we are moving at nearly the speed of light away from that original reference frame. Thus I concluded my calculation is faulty.4) I am wondering if there could be additional factors contributing to the loss of the photonís energy. Factors that are not related to the reference frames. Is it possible that the photon is losing energy because it is moving out of a high density cosmos and into a less dense cosmos? Could there be a gravity well that this photon is climbing out of. Was their larger gravity forces acting on this photon when the universe was young compared to the present lower density universe? Letís assume this photon is not absorbed and reemitted via interactions with matter. Letís assume the only interaction this photon has is with the expanding universe and any possible gravity well it might be climbing out of. 5) This photon does not experience the passage of time. As far as it is concerned it has just been emitted from the last scattering surface, the CMBR (cosmic microwave background radiation), even though it took 13.4 billion years to get here. 6) The photon must have zero energy in its own reference frame because its wavelength must be infinitely long. But if this is true does the photon even exist in its own reference frame. I would think zero energy means nonexistence. 7) I didnít really follow the phase velocity and group velocity descriptions. Cheers