Massive Photon

I think the mass of a photon is h/lambda*c.

And why is that? I hate to even ask.

BTW, can't tell if you are trying to say... h/ (lambda x c)
..or .... (h/lambda) x c

...

h/(lambda*c)

And your reasoning is.... ??

Go ahead and try to convince me...


.....

h/lambda=p

h/lambda=mv

h/(lambda*v)=m

E=mc^2
=(h/(lambda*c)*c^2
=hc/lambda

E=pc
=hc/lambda

Units
(m^2.kg(m/s))/(m(m/s))=kg

Why do you need a photon mass? It is not a particle to be accelerated in a regular sense of the Newton mechanics. Where are you going to put this mass?

This post has been edited by Bob_for_short on Jan 30 2010, 07:29 PM

That's a loaded question.

In the Catholic church where all the other Catholics have mass.

de Broglie was he first to claim this.

This incorrectly assumes p = mv, which is experimentally not true when v is close to the speed of light. Alternately you are defining m as p/v which would mean objects at rest have no well-defined mass which would destroy commerce of goods sold by mass and it makes m a function of v which is observer-dependent.

This incorrectly assumes p = 0 and v=0, which is not true when v is close to the speed of light. Alternately you are defining m as E/c^2, which is non-standard because it makes m a function of v.

This is only true if you say light always moves at v=c which is accepting relativity.

This result, which was gotten at in a suspicious way, contradicts your clarification of your initial post. But it is true for light.

Again, true for light.

For all particles, special relativity states:

E² = m²c⁴ + p²c²
and
v = pc²/E

So m² = (E² - p²c²)/c⁴ is a constant even when v, E, and p may change due to different observers.

And since for a photon, |p| = E/c, then
m² = (E² - p²c²)/c⁴ = (E² - (E²/c²)c²)/c⁴ = (E² - E²)/c⁴ = 0
|v| = |p|c²/E = (E/c)c²/E = c


deBroglie writes that p = h/λ and E = hf for all particles. This was an early statement in quantum physics and would suggest that electrons and neutrons can create diffraction patterns, which is experimental demonstration of their periodic nature in space. Plugging that in we get

m² = (E² - p²c²)/c⁴ = (h²f² - h²c²/λ²)/c⁴ = (f² - c²/λ²)(h²/c⁴)
And
v = pc²/E = (h/λ)c²/(hf) = c²/(fλ)
which we re-write as λ = c²/(fv) and substitute in the first equation as:
m² = (f² - c²/λ²)(h²/c⁴) = (f² - f²v²/c²)(h²/c⁴)

And so if v = c, m = 0 because m² = (f² - f²v²/c²)(h²/c⁴) = 0.

nevermind; i'll wait for his answer to rpenner.



This post has been edited by Lunarlanding on Jan 31 2010, 02:31 AM

How do you explain this?

...... Er? - like, he completely did.

p.s;- Is the "AAA" part of your moniker, any reference to the remarkably spent power source to your brain. Or just a crazy failed attempt @ the English alphabet?

Iv'e told you before AAA123, you should not assume E=mc^2 is true for all particles. Its only true for massive particles at rest. The proper expression is E^2 = (mc^2)^2 + (pc)^2 and for photons m=0. In special relativity this follows from the fact photons move along null trajectories, ie ds^2=0. p^a p^b eta_ab = 0 therefore and you end up with E^2 = (pc)^2 so E=pc.

You're trying to use high school algebra on a theory which requires more knowledge and understanding. Do you really think you are the first to wonder about E=mc^2 and E=hf? The problem is you don't understand relativity and you're just very very stupid.

How do you explain this?

Substituting h/(lambda*c) in E=(mc^2)+pc:

E=(hc/lambda)+(hc/lambda)

E=2mc^2=hf

This post has been edited by AAA123 on Jan 31 2010, 10:36 AM

Many people (also scientists, also physicists) try to reduce physics to mathematics. But unfortunately, physics realizes only a few mathematical equations among the millions formulated within mathematics. In this thread once more is discussed a difference between mass and massless energy. Massless energy cannot be in existence without fields having mass density. The massless photons are the real massless objects only because there is the Einstein spacetime having mass density. We can say that the Einstein spacetime carries the massless photons. Without the Einstein spacetime, i.e. without the field having mass density, the photons cannot be in existence.
I claim that the Einstein spacetime consists of the free binary systems of neutrinos. It means that the carriers of photons (not the photons) have mass. Elementary carrier has mass equal to 6.6•10^-67 kg. Due to the weak charges of the neutrinos, the binary systems of neutrinos can be entangled so also the massless photons can be entangled. Maximal number of entangled elementary photons is 2•4^32. Such entangled photons have lifetime – for example, they decay to the photon galaxies (a photon galaxy contains 4^16 entangled elementary photons) after about 15 billion years. For example, the decaying photons are responsible for the observational fact that the supernovae Ia having redshift greater than about 0.28 are darker than it results from their distance from us. The nearer supernovae Ia are brighter due to the decays of the entangled photons produced before the big bang in processes that broken symmetry of the Einstein spacetime, not due to an acceleration of expansion of the Universe.
It is very difficult to detect the mass of the components of the Einstein spacetime because in the ground state of the Einstein spacetime the spins of the binary systems of neutrinos do not rotate so they cannot transfer some energy to detector – I think that they will be discovered in the LHC experiments.

Recapitulation
The photons are massless in the electromagnetism because the theory of electromagnetism is separated from the internal structure of the Einstein spacetime having mass density. The speed of light is the natural speed of photons in the more fundamental spacetime than the Einstein spacetime i.e. in the Newtonian spacetime that is DIRECTLY associated with origin of the mass.
Two colliding photons, having appropriate energy, create an electron-positron pair HAVING MASS due to the compression of a part of the Einstein spacetime (having mass density). It leads to the E=mc^2. There are not in existence Higgs bosons or the Higgs field composed of…..
Unless we assume that: Higgs field = Einstein spacetime = gas composed of binary systems of neutrinos having mass density.
Dark energy is the region of infinite cosmos having higher mass density of the Einstein spacetime. Just after the beginning of the big bang, the overflowing condensation of the Einstein spacetime accelerated expansion of the Universe but it was during about the first two billion years after the beginning of the big bang.

This post has been edited by Sylwester Kornowski on Jan 31 2010, 11:17 AM