Does energy contain mass?

[Just thinking]

From http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html:

Yes, yes ... but it also gives another answer:

"One answer is that any particles such as photons of light, move along geodesics in general relativity and the path they follow is independent of their mass."

This would suggest that their relativistic mass is of no consequence.

Don't get me wrong ... I'm not 100% sure of either case, but it appears neither is anyone else. I think drkitten got it with ...

"Part of the problem here is that you're looking at two incompatible theories of physics. Space-time curvature is an effect predicted and modelled by the (general) Theory of Relativity, while gravitational coupling and the exchange of gravitons is Quantum Mechanics. Unfortunately, these theories don't work together [yet?], and greater minds than mine have spent many years trying to figure out a way to reconcile and unify the two."

 

[TillEulenspiegel]

Much of the problem We have in understanding the nature of matter/energy equivalence and QM is because it is the difficulty of trying to describe exactly a concept that is both counter intuitive and using the symbolic (language) that falls short.

The question as stated -

Does energy contain mass?


-... is not really the question.
If you want to be syntactically and pedantically correct the answer is no. Energy does not “contain “ mass, not like a chemical suspension or solution, rather energy is equivalent to a given mass . STR states that energy and mass are equivalent. They are different forms of the same thing.

When Physicists perform an experiment in a particle accelerator, mass is measured in terms of energy I.E. MEV, BEV – Millions/Billions of Electron Volts. That is the reality of Einstein's equation.
Secondly, the photon is not the best foothold to try and grasp the idea of gravity. The photon even in the strange world of QM has peculiar properties, here comes the monkey wrench. QM describes a photon is timeless and spaceless, meaning that the quanta is traveling at c, it has no rest mass as stated and ( heres the kicker) exists everywhere at once.

As Dr.NK stated there are two incompatible theories, of gravity GTR and Quantum gravity GTR is generally understood ,QG is being fleshed out but the problem is that there appears to be no point of agreement. Both theories work extremaly well to a certain point and then break down That is one reason that string theory is a promising area of study now, it appears to reconcile the differences between the Relativistic and the QM models of gravity.

I would study point particles to gain an understanding of the energy/mass question rather then photons.
Very good text here
http://relativity.livingreviews.org/Articles/lrr-2004-6/download/lrr-2004-6Color.pdf

 

[hammegk]

Part of the problem here is that you're looking at two incompatible theories of physics.

Or, as someone else mentioned previously.

"Let me know if you conclude the answer is any better than 'Duh, we dunno what "Energy" is', or 'goddidit'."

 

[69dodge]

Originally posted by Just thinking
Yes, yes ... but it also gives another answer:

"One answer is that any particles such as photons of light, move along geodesics in general relativity and the path they follow is independent of their mass."

That answer was given in response to the question: "If light has no mass how can it be deflected by the gravity of a star?" It does not address the question of whether light has its own gravity which can deflect other things.

Particles that have rest mass also follow geodesics in spacetime.

 

[TillEulenspiegel]

"One answer is that any particles such as photons of light, move...

Thats a misnomer Photons are not a particle but a "Quanta". a packet of energy.

Another is the characterization of a geodesic . A geodesic is the shortest path in curved space between coordinates in spacetime.

Thirdly there is a coupling of photons ( and point particles) and the gravitational effects of larger bodies, the influence between either of these on a large body will reduce to a negligible mathematical curiosity.