3 question About Photons.

E

EmptyForceOfChi

Banned
Banned
1) How much do 7 photons weigh combined.

2) How much does a Photon weigh on Earth Compared to On Jupiter.

3) How much does a Photon Weigh Under Water.



Peace.
 
Photons will exist in two references at the same time. Since they travel at C, they see space-time contracted to a point, with this reference, independent of any inertial reference. The speed of light stays the same.

Photons also have a finite aspects connected to what we see as frequency and wavelength. These are dependent on reference, being red shifted and blue shifted based on the relativity of gravity and/or motion. But the C reference stays the same.

If we took two identical photons, one going onto the earth and the other onto Jupiter, since Jupiter has higher gravity it will blue shift the finite aspect of the photon more. The speed of light aspect will not change in either case. Blue shifted energy defines more energy, so if we use the equivalence of mass/energy, it will weight more on Jupiter.
 
wellwisher said:
Photons will exist in two references at the same time. Since they travel at C, they see space-time contracted to a point, with this reference, independent of any inertial reference. The speed of light stays the same.

Photons also have a finite aspects connected to what we see as frequency and wavelength. These are dependent on reference, being red shifted and blue shifted based on the relativity of gravity and/or motion. But the C reference stays the same.

If we took two identical photons, one going onto the earth and the other onto Jupiter, since Jupiter has higher gravity it will blue shift the finite aspect of the photon more. The speed of light aspect will not change in either case. Blue shifted energy defines more energy, so if we use the equivalence of mass/energy, it will weight more on Jupiter.
Click to expand...



Energy always transforms into other types of energy, What is the cause and effect sequence of photon transformation. or is each photon eternal without change of form. Changing from blue shift to red shift technically the photon is remaining a photon without actual change no?.



peace.
 
EmptyForceOfChi said:
Can any M truly = 0?.
Click to expand...
Yes. We're talking about subatomic particles here, not objects.
I mean shouldn't it be at least 0.000000000000.000000.01 instead of an absolute 0?
Click to expand...
No. Photons travel at the speed of light. Like, by definition: remember, light is photons? Only something with zero mass can reach the speed of light.

If at this point you're not slapping your forehead and saying, "Oh how stupid! I knew that!" then you need to review your university class notes on relativity, because nothing in this thread is going to make a bit of sense to you.
If something is truly 0 would it physicaly exist as a tangible thing.
Click to expand...
You're drilling down to the level of quarks, leptons and bosons here. Half of everything you know about physics is no longer relevant.

After all, the word "tangible" means, literally, "able to be touched." You cannot touch a photon, an electron, or a neutrino. There's nothing tangible in the realm of microcosmology.
 
A question...

Matter can be converted to energy and vice versa..


Is there any process that converts Photons to matter?
 
GiantRob said:
Matter can be converted to energy and vice versa..


Is there any process that converts Photons to matter?
Click to expand...

I'm not sure the wording "converts photons to matter" is quite right, but massive particles can arise from photon interactions if the system has enough energy.

http://en.wikipedia.org/wiki/Two-photon_physics

This stuff is a bit beyond me, but there a people here who know a lot about this kinda stuff.
 
EmptyForceOfChi said:
Can any M truly = 0?. I mean shouldnt be atleast 0.000000000000.000000.01 instead of an absolute 0?. If something is truly 0 would it physicaly exist as a tangible thing.

peace.
Click to expand...

Theoretically, photons have zero rest mass. Experimentally photons have been measured to have a rest mass smaller than a very tiny number, compatible with the theory which says this number is zero.

Remember it is just the rest mass which is zero. Photons still carry kinetic energy and momentum. Light bouncing off things exerts a force, so it is certainly tangible in that sense. If something had both no rest mass and no kinetic energy THEN you could say it doesn't really exist anymore. This is part of why photons must travel at the speed of light always. If they didn't, there would be a frame of reference where they had zero kinetic energy, and the photon would effectively not exist in that frame. This would be a problem.

GiantRob said:
Matter can be converted to energy and vice versa..

Is there any process that converts Photons to matter?
Click to expand...

Yes indeed. If a photon has enough kinetic energy it can spontaneously turn into an electron-positron pair, for instance. You need quite high energy photons for this though, in the gamma ray regime, because electrons (and positrons) have a rest mass of 511 keV, so to create two of them you need two photons of around 511 keV to "collide", if you will accept the use of the term. You could also crash a high energy photon into a bunch of other things and have it's energy converted to matter particles some of the time.

If you mean is there a process that can reliably convert photons into matter with good efficiency, then no, I don't know of such.
 
Fraggle Rocker said:
Yes. We're talking about subatomic particles here, not objects.No. Photons travel at the speed of light. Like, by definition: remember, light is photons? Only something with zero mass can reach the speed of light.

If at this point you're not slapping your forehead and saying, "Oh how stupid! I knew that!" then you need to review your university class notes on relativity, because nothing in this thread is going to make a bit of sense to you.You're drilling down to the level of quarks, leptons and bosons here. Half of everything you know about physics is no longer relevant.

After all, the word "tangible" means, literally, "able to be touched." You cannot touch a photon, an electron, or a neutrino. There's nothing tangible in the realm of microcosmology.
Click to expand...


Yeah I do Over-stand the concept :p I know that photons are not the same as atomic mass and it is more akin to thermal dynamics and electro-magnetism in nature.


I beg to differ about touching photons this is actualy one of the reasons I started to question this again. When you place a solid object in the path of light beams or "Photons" The beams `Do inter-act with the Physical mass and you can technically *Hold* Photons in a way since they did not travel through your solid hand and then started to reflect on "impact" or upon touching/collision.


Now with water aswell, this causes light to refract but still alows it to pass throough in a distorted tragectory or so it would appear to the eyes atleast in true reality. So translucient and opaque M does create different effects on photons making them tangible no?.



Peace.
 
Fraggle Rocker said:
Photons travel at the speed of light. Like, by definition: remember, light is photons? Only something with zero mass can reach the speed of light.
Click to expand...

This is interesting actually. I think it is a shame that 'c' has the name 'speed of light'. Let me explain.
Relativity theory, although Einstein rambled on about light a lot when he was formulating it, actually has nothing to do with light directly. It is a theory of spacetime. 'c' is just a parameter which characterises the structure of spacetime. The fact that light travels at c is a consequence of this structure (and the fact that light is massless), not the other way around.
So it is possible that statements like "photons travel at the speed of light" might become really confusing one day, if we find out that photons have a really tiny mass. 'c' would remain the same number, but the speed of light would actually be frame dependent, you would just need amazingly high energies to notice (i.e. higher than the energies the protons at the LHC are circulating...). At least that is one possible scenario :). I don't actually think that will happen, at least not in my lifetime, because the theory that says photons are massless is very convincing and well supported, but I like to acknowledge the possibility :).
 
kurros said:
This is interesting actually. I think it is a shame that 'c' has the name 'speed of light'. Let me explain.
Relativity theory, although Einstein rambled on about light a lot when he was formulating it, actually has nothing to do with light directly. It is a theory of spacetime. 'c' is just a parameter which characterises the structure of spacetime. The fact that light travels at c is a consequence of this structure (and the fact that light is massless), not the other way around.
So it is possible that statements like "photons travel at the speed of light" might become really confusing one day, if we find out that photons have a really tiny mass. 'c' would remain the same number, but the speed of light would actually be frame dependent, you would just need amazingly high energies to notice (i.e. higher than the energies the protons at the LHC are circulating...). At least that is one possible scenario :). I don't actually think that will happen, at least not in my lifetime, because the theory that says photons are massless is very convincing and well supported, but I like to acknowledge the possibility :).
Click to expand...

It wasn't Einstein who stated that the speed of light was invariable
and the maximum speed. He took that as a postulate in his theory. It was Maxwell's equations which established the above.

It's always comforting when theory is bolstered by experimentation. Currently, the mass of the photon has been measured at NO HIGHER than 7 × 10-17 eV. That doesn't mean that ANY mass has been detected, it just means that 7 × 10-17 eV is the limit of experimental accuracy at this time. Studies of galactic magnetic fields suggest a much better limit of less than 3 × 10-27 eV, but there is some doubt about the validity of this method.

The point is, theory states that the photon should be massless, and experimentation and observation support that, to the limit of our current technology.

Should increasingly accurate measurements detect a mass of the photon, all existing theory, (which has been experimentally verified to an astounding degree of accuracy) would have to be totally discarded.
 
You must log in or register to reply here.
Back
Top