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Physics, Astronomy & Cosmology / How old are photons?
« on: 26/08/2009 22:15:17 »
Good question!
I think the overall answer is no, because there is no opportunity for transition at light speed. This is why we currently believe that neutrinos have some mass; we know that some neutrinos change aspect between here and the sun, which means that they are travelling at less than light speed, which means that they have mass.
In the case of the different media, I have to think on that myself. When a photon enters a medium, there is a definite event, so that makes a difference. It could be that the medium includes the absorption and re-emission of light as well, events that can change the nature of what we identify as the same light.
I think the overall answer is no, because there is no opportunity for transition at light speed. This is why we currently believe that neutrinos have some mass; we know that some neutrinos change aspect between here and the sun, which means that they are travelling at less than light speed, which means that they have mass.
In the case of the different media, I have to think on that myself. When a photon enters a medium, there is a definite event, so that makes a difference. It could be that the medium includes the absorption and re-emission of light as well, events that can change the nature of what we identify as the same light.