Davros Posted June 17, 2005 Posted June 17, 2005 I am not a scientist but have a general interest in relativity. I am annoyed by the ever growing need to introduce exotic matter and additional dimensions into theories to account for effects in our universe. I have what maybe a completely silly idea (but would really like that to be confirmed! ) that may have a germ of interest .... 1. Suppose that the maximum velocity posssible in our universe was 0.0000005% higher than c. Call this c++. 2. light still has a measurable velocity c. But c is less than c++. Possibly from this a photon has mass. 3. If a photon has mass, why have we not detected it? Maybe because it is so so minimal. So minimal that even when traveling at 99.9999995% of c++ when it had maybe 10,000 times the mass of a photon at rest, it is still a minimal and undetectable mass (todate). 4. What would be the consequencies of a photon having minimal mass, rather than zero mass? A. Possibly this is the allusive Dark Matter? B. photons colliding with anything (planets/eyeballs) inflict a force. (However, assuming we receive countless photons from all directions all the time. these forces cancel out). C. Several formula to deal with singularities and expansion would be 'slightly' out and annoying ambiguities accounted for? (eg possible variance in value of c over time, possible variance of gravitational effects over distance) Anyhow, my question is, is this idea a dead duck non-starter? or could it possibly be just very unlikely?
mezarashi Posted June 17, 2005 Posted June 17, 2005 Dark matter is in fact not "exotic". Dark matter is simply matter that does not emit or reflect any substantial amount of electromagnetic radiation, thus serving it undetectable by our equipment here on Earth. How would you detect our own planet Earth for example 10 million light years away if it weren't for the Earth reflecting the sun's light. Photons actually do "inflict a force" when they are absorbed. Have you seen solar sails? You can get light to essentially "push" stuff. While photons are massless, they have momentum p which is a function of their frequency. The idea that a photon is massless was not hypothetical, but I will leave the reason for the consequence to someone more knowledgeable >_>
ydoaPs Posted June 17, 2005 Posted June 17, 2005 as for the photon having mass, i have an equation about that. i will look for it.
ydoaPs Posted June 17, 2005 Posted June 17, 2005 equation for photon mass if photons didn't move at c: [math]m=\frac{h{\sqrt{v^2-c^2}}}{\lambda{c^2}}[/math]
ydoaPs Posted June 18, 2005 Posted June 18, 2005 actually, that can be simplified more: [math]m={p}\frac{\sqrt{v^2-c^2}}{c^2}[/math]
greentea Posted June 18, 2005 Posted June 18, 2005 as for photons exerting force, there is something less exotic than a solar sail. lasers. they are actually already used in biophysics to measure forces between single molecules.
bascule Posted June 18, 2005 Posted June 18, 2005 Or as simple as a device with small squares of paper colored white on one side and black on the other, arrayed around a spinning mechanism. When the device is exposed to light, the mass of the photons reflected by the white side is enough to push it around.
swansont Posted June 18, 2005 Posted June 18, 2005 Or as simple as a device with small squares of paper colored white on one side and black on the other, arrayed around a spinning mechanism. When the device is exposed to light, the mass of the photons reflected by the white side is enough to push it around. Crookes radiometer. These use the different heating of the two sides, and the gas pressure difference that ensues. Radiation pressure is a lot smaller.
ydoaPs Posted June 18, 2005 Posted June 18, 2005 i guess i should have elaborated, but it wasn't entirely necessary. i was talking bout the same thing swansont said.
Janus Posted June 18, 2005 Posted June 18, 2005 I am not a scientist but have a general interest in relativity.I am annoyed by the ever growing need to introduce exotic matter and additional dimensions into theories to account for effects in our universe. I have what maybe a completely silly idea (but would really like that to be confirmed! ) that may have a germ of interest .... 1. Suppose that the maximum velocity posssible in our universe was 0.0000005% higher than c. Call this c++. 2. light still has a measurable velocity c. But c is less than c++. Possibly from this a photon has mass. 3. If a photon has mass' date=' why have we not detected it? Maybe because it is so so minimal. So minimal that even when traveling at 99.9999995% of c++ when it had maybe 10,000 times the mass of a photon at rest, it is still a minimal and undetectable mass (todate). 4. What would be the consequencies of a photon having minimal mass, rather than zero mass? A. Possibly this is the allusive Dark Matter? B. photons colliding with anything (planets/eyeballs) inflict a force. (However, assuming we receive countless photons from all directions all the time. these forces cancel out). C. Several formula to deal with singularities and expansion would be 'slightly' out and annoying ambiguities accounted for? (eg possible variance in value of c over time, possible variance of gravitational effects over distance) Anyhow, my question is, is this idea a dead duck non-starter? or could it possibly be just very unlikely?[/quote'] I'd have to say dead duck non starter for a couple of reasons: 1. Observations of galaxies and their rotation show that dark matter concentrates in halos surrounding these galaxies, light does not do this. 2. There simply isn't enough light to account for dark matter. Dark matter is estimated to make up over 90% of the matter of the universe. The upper limit for the mass of a photon(if it were to have one) due to our present sensitivity of equipment is 4 x 10^-48 g. Thats 2 * 10^20 times smaller than the mass of the electron. The night sky would have to be literally glowing.
Davros Posted June 20, 2005 Author Posted June 20, 2005 thanks Janus, that was the answer I was looking for. thanks for the formulae yourdadonapogos.
bascule Posted June 24, 2005 Posted June 24, 2005 Crookes radiometer. These use the different heating of the two sides, and the gas pressure difference that ensues. Radiation pressure is a lot smaller. A few days after posting this I watched the Connections episode on the radiometer and realized everything I just posted was wrong... ugh
Severian Posted June 25, 2005 Posted June 25, 2005 A photon mass wouldn't be enough. The limits on the photon mass are now very tight and it could not provide enough mass for dark matter. Also, as pointed out already, the rotation curves of glaxies would be wrong (although you could say that you have 2 types of dark matter). Also, what right do you have to be 'annoyed' by the inclusion of exotic matter? Quarks were 'exotic' when they were suggested - were you annoyed by them too? In fact most modern theories of particle physics need new particles in order to work (and explain current problems) and one of the problems is that they often predict too much dark matter. It is really easy to have dark matter in a theory - all you need is a neutral, colorless massive particle. As for photons exerting a force, what do you think electromagnetism is?
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