Re: PHOTON MASS -- A FACT. MASSLESS PARTICLES -- NOT FACT.


FrediFizzx wrote:
"Phineas T Puddleduck" <phineaspuddleduck@xxxxxxxxxxxxxxxxxxxxx> wrote
in message
news:230620061822288721%phineaspuddleduck@xxxxxxxxxxxxxxxxxxxxxxxx
In article <4g2lh0F1ktqp8U1@xxxxxxxxxxxxxx>, FrediFizzx
<fredifizzx@xxxxxxxxxxx> wrote:

In the case of a single photon, yes. That is if we are talking
about
rest mass. Even though we have E = mc^2, it mainly just means that
mass
units can be used to express energy and like-wise. But energy and
mass
are not the same thing. I read papers all the time that use the
concept
of photon mass in their arguments. But a photon should have zero
rest
mass and from a theoretical standpoint, there is no reason why it
should
have any rest mass, IMHO.

FrediFizzx
http://www.vacuum-physics.com


http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.htm
l

To quote

"This question comes up in the context of wondering whether photons
are
really "massless," since, after all, they have nonzero energy and
energy is equivalent to mass according to Einstein's equation E=mc2.
The problem is simply that people are using two different definitions
of mass. The overwhelming consensus among physicists today is to say
that photons are massless. However, it is possible to assign a
"relativistic mass" to a photon which depends upon its wavelength.
This is based upon an old usage of the word "mass" which, though not
strictly wrong, is not used much today. See also the Faq article Does
mass change with velocity?.

The old definition of mass, called "relativistic mass," assigns a mass
to a particle proportional to its total energy E, and involved the
speed of light, c, in the proportionality constant:

m = E / c^2. (1)

This definition gives every object a velocity-dependent mass.

VERGON
Hold the phone. When Einstein wrote that equation he was speaking
SPECIFICALLY
of radiation. And in radiation mass is NOT dependent on velocity but on
frequency.

Velocity-dependent mass is given by p = mv gamma. And it is recognized
as invalid.

(Got to watch you guys. Your'e sloppy) :-)
In fact, some day I will explain to you that it is not the mass that
goes to infinity but the velocity.


The modern definition assigns every object just one mass, an invariant
quantity that does not depend on velocity. This is given by

m = E0 / c^2, (2)

where E0 is the total energy of that object at rest."

Yep, that is another way of saying what I did. And even our QVC
relativistic medium scenario totally agrees with it. ;-) I just don't
know why people want to give rest mass to a photon. ;-( When
physicists use photon mass in papers, they are using (1) and it is
usually clear from what they are talking about that it is not rest mass
but they are just using the term mass for energy. And likewise.

VERGON
I don't know why there is such confusion about rest mass. When a photon
is absorbed, it no longer exists and it's mass and energy are
transfered to the electron absorbing it.


FrediFizzx
http://www.vacuum-physics.com

.

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