SciContest! Why can't matter be made of photons?

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promethus said:
This is the first law of thermodynamics, and is a very basic notion in physics.
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If you add the energy to a golf ball via a club you increase its momentum directly. Adding heat to it increases its mass, so if it is moving and everything must be; we're still in orbit I think; if it is moving its momentum increases.

Poincare's contribution to SR is widely known. Why do you object to it?
 
My 2 cents.

Conservation laws. By abiding to the energy-mass conservation law, by converting photons into an electron, for example, we violate other conservation laws such as spin and charge.
 
Not true.

In some form or another conservation laws are running the show. Take the idea that two particles an electron and a positron come together, the conservation law of momentum states that at least two photons be created. So from ordinary matter, we can make photon energy, and we can make matter from photons as well. Everything is conserved, or this process would be lost.
 
i have heard that a photon of sufficiently large energy (high frequency) can be converted into a matter particle and it's anti-particle using a clever trick. The trick is to fire it close to the nucleus so that the the particle and it's anti-particle seperate enough to exist independently
 
Ok. I promised myself that I wouldn't forget about this, then I did. Then I remembered, then I got busy.

This thing was resolved in September, and I never made public the results.

Congratulations Janus58, for your nice dimensional analysis argument.

Feel free to continue the discussion, but the matter is settled.
 
BenTheMan said:
Ok. I promised myself that I wouldn't forget about this, then I did. Then I remembered, then I got busy.
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Hi BenTheMan; your reference to the Fine Structure Constant sent me into a month- long study that concluded with how the fine structure constant relates to a photon-only universe. I had not thought of that before. I still think you are one of the few people in this universe who is capable of resolving Einstein's greatest dream. His unification of the forces. :) Hope I'm not causing you any grief.
 
Vern said:
If you add the energy to a golf ball via a club you increase its momentum directly.
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No argument from me here, although strictly speaking momentum is being transferred from the club to the ball, or you are transferring kinetic energy from the club to the ball. Energy and momentum are not interchangeable.

Vern said:
Adding heat to it increases its mass,
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Wrong. I assume you're thinking that increasing something's temperature increases the kinetic energy of the constituent particles and that means they get more relativistic mass. Well relativistic mass is an extremely poor concept because it's not really a mass, it's an energy so we could say that the internal energy of the body has increased, not the mass.

In a bit more depth, mass cannot be velocity dependant because it is defined to be the invariant norm of the momentum four vector. Notice the word "invariant" in there. Mass as defined does not depend on velocity. If you want mass to depend on velocity then the theory becomes mathematically inconsistent, Poincare or not.

Vern said:
...so if it is moving and everything must be; we're still in orbit I think; if it is moving its momentum increases.
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Sorry, but this is gibberish.
 
BenTheMan said:
Ok. I promised myself that I wouldn't forget about this, then I did. Then I remembered, then I got busy.

This thing was resolved in September, and I never made public the results.

Congratulations Janus58, for your nice dimensional analysis argument.

Feel free to continue the discussion, but the matter is settled.
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FYI here is the winning post linky

Congrats Janus58! :)
 
prometheous said:
In a bit more depth, mass cannot be velocity dependant because it is defined to be the invariant norm of the momentum four vector.
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I thought momentum was mass times velocity, I think I remember someone using p = mv to determine the momentum p.

Congrats to Janus58. However the diameter of the electron was assumed to be less than a certain value because that was the measuring limits and nothing was detected. There is another possibility, however. The other much more likely possibility is that there was nothing there to detect. The electron only exists at its electromagnetic diameter.
 
Invariant norm of the momentum four vector means

$$ \eta^{\mu \nu} p_\mu p_\nu = \frac{E^2}{c^2}-\vec{p} .\vec{p}=m^2c^2 $$

With a bit of rearranging you get

$$E^2 = \left| \vec{p} \right|^2 c^2 + \left(m c^2\right)^2$$

which clearly reduces to $$E = mc^2$$ when $$\vec{p}=0$$ or in the rest frame of the particle.
 
John said:
i have heard that a photon of sufficiently large energy (high frequency) can be converted into a matter particle and it's anti-particle using a clever trick. The trick is to fire it close to the nucleus so that the the particle and it's anti-particle seperate enough to exist independently
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You don't even have to do a trick. All you need is enough energy at the right frequency and photons become massive particles.

prometheous: Your arithmetic is good, so I'll change my thinking. A photon is not mass. It is only potential mass. Any time it is confined such as bouncing around inside a mirrored box, or between atoms, it then becomes mass.
 
BenTheMan said:
Ok. I promised myself that I wouldn't forget about this, then I did. Then I remembered, then I got busy.

This thing was resolved in September, and I never made public the results.

Congratulations Janus58, for your nice dimensional analysis argument.

Feel free to continue the discussion, but the matter is settled.
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Oh how wonderful of you to finally remember... months later... :eek:

Oh well Janus, you've won strictly on erreneous grounds, meaning the thread was giving out a false contest supposing matter could not be made of photons. Oh well, we live and learn.
 
gluon said:
Oh well Janus, you've won strictly on erreneous grounds, meaning the thread was giving out a false contest supposing matter could not be made of photons. Oh well, we live and learn.
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I think the Janus58 entry was a good choice since the OP asked for the BEST entry. Not necessarily one that could show the concept false.

But let the record show, there was no entry that could qualify as a killer for the photon-only concept.
 
BenTheMan said:
Ok. I promised myself that I wouldn't forget about this, then I did. Then I remembered, then I got busy.

This thing was resolved in September, and I never made public the results.

Congratulations Janus58, for your nice dimensional analysis argument.

Feel free to continue the discussion, but the matter is settled.
Click to expand...

And here I am without an acceptance speech ready. I mean, who would have thought that the son of an iron miner, raised on a farm in the Mesabi range, would grow up to win this contest.

So anyway, I'll just thank Ben for sponsoring and judging the contest. It was fun.
 
Janus58 said:
And here I am without an acceptance speech ready. I mean, who would have thought that the son of an iron miner, raised on a farm in the Mesabi range, would grow up to win this contest.

So anyway, I'll just thank Ben for sponsoring and judging the contest. It was fun.
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congradulations on winning the 'physicists choice' award!

Why matter can not be made up of photons.

Argument:

The radius of the Electron is less than 10^-13 m
The mass of the Electron is 9.1e-31 kg
The energy equivalence of the mass of an electron is 8.14e-14 joules
The wavelength of a single photon with the energy equivalence of the mass of an electron is 2.43e-12 m, about 10 times the diameter of the electron.

Ergo, for an electron to be made up of a single photon, it would have to be made up of something larger than its own diameter.

Trying to have the electron being made up of more than one photon makes the problem worse. Each photon would have to have a fraction of the energy equivalence of the electron, and as the energy of a photon decreases, its wavelength increases.
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that sentence

Each photon would have to have a fraction of the energy equivalence of the electron, and as the energy of a photon decreases, its wavelength increases. is true (see radio vs gamma)

did you have another point?
 
Vern said:
You don't even have to do a trick. All you need is enough energy at the right frequency and photons become massive particles.
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Probably true. Just that using the positively charged nucleus trick means that one can generate particles at smaller energies
 
John said:
Probably true. Just that using the positively charged nucleus trick means that one can generate particles at smaller energies
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Interesting; I had never seen that before. Do you have a reference as to where you came across this info?
 
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