Best accepted physics theory

[Mr Skeptic]

Which of the major physics theories do you think are the most rock-solid? That have no chance whatsoever of being overturned?

 

I think it is electromagnetism. There's no paradoxes that I'm aware of with electromagnetism. Nothing extremely unintuitive, though a few people have problems with the perpendicular nature of electricity and magnetism. No conflicts that I know of with other theories. It doesn't break down anywhere. At most, people have suggested making the equations symmetrical by adding in magnetic monopoles. The version that includes magnetic monopoles and the effect they would have seems to be unquestionable (the claim that magnetic monopoles don't exist wouldn't change the equation, it would just mean that some terms are always zero). So far as I know, there is no attempt to replace electromagnetism. You do get the occasional nutjobs that think magnets are magical or that a certain paper showing gravity acting with an equation similar to magnetism literally meant magnetism.

 

Some of the stuff Newton did also seems unquestionable. The law of equal and opposite forces, the law of conservation of momentum, the definition of force (so long as you don't assume mass is constant), the law of conservation of energy. OK, so lots of people try to find ways around the law of conservation of energy but it is also always backed up by the other laws of physics.

 

For relativity and quantum, these are full of paradoxes and inintuitiveness. Also, they contradict each other as relativity says gravity is due to warped spacetime but quantum says gravity is due to gravitons. Theories to join the two are still in the development stage, not ready to replace both nor either any time soon.

 

Hopefully this is not a dumb discussion and doesn't attract nutjobs. Anyways, which do you think are the most rock solid physics theories?

[ajb]

Which of the major physics theories do you think are the most rock-solid? That have no chance whatsoever of being overturned?

 

General relativity and the standard model have both agree remarkably with nature. However, both are known not to be complete. I am not sure what is meant by " no chance of being overturned". General relativity and the standard model are not going to be overturned, but they are going to be shown as part of a larger theory.

 

I think it is electromagnetism. There's no paradoxes that I'm aware of with electromagnetism.

of with other theories. It doesn't break down anywhere. At most, people have suggested making the equations symmetrical by adding in magnetic monopoles. The version that includes magnetic monopoles and the effect they would have seems to be unquestionable (the claim that magnetic monopoles don't exist wouldn't change the equation, it would just mean that some terms are always zero). So far as I know, there is no attempt to replace electromagnetism. You do get the occasional nutjobs that think magnets are magical or that a certain paper showing gravity acting with an equation similar to magnetism literally meant magnetism.

 

Classical or quantum electrodynamics?

 

The quantum version as part of the standard model agree with nature immaculately. There are still some formal issues, for example the mathematical existence of the interaction picture. (See Haag's theorem.)

 

I think monopoles will be discovered. They seem unavoidable in supersymmetric theories of unification.

 

 

 

For relativity and quantum, these are full of paradoxes and inintuitiveness. Also, they contradict each other as relativity says gravity is due to warped spacetime but quantum says gravity is due to gravitons. Theories to join the two are still in the development stage, not ready to replace both nor either any time soon.

 

Maybe a quantum theory of gravity is not a theory of gravitons. I have posted on this before. Particles are part of perturbative quantum field theory. We know this does not work for general relativity (+ higher curvature terms). But there is evidence it may be well founded outside of pertubation theory. Thus, quantum gravity but no gravitons.

 

Hopefully this is not a dumb discussion and doesn't attract nutjobs. Anyways, which do you think are the most rock solid physics theories?

 

I believe, as do many others, that quantum field theory is the general mathematical framework of nature. I do not see that point of view diminishing any time soon.

 

Now for something more speculative. I also think that there maybe a role for generalisations of Lie algebras, the [math]L_{\infty}[/math] and Filippov algebras in fundamental physics. Such structures have been known for a little while now, and can be found in string field theory, deformation theory, BV-antifield formalism and M-theory via the BLG-model of stacked M2-branes. I wonder if such things (and other homotopy algebras) will play a role tomorrow similar to Lie theory today.

Edited December 7, 2009 by ajb

[CharonY]

Wouldn't be the laws of thermodynamics up on the list?

[One of the Few]

The most obvious is of course newton's laws. They are 100% solid, granted there are a few inconsistencies, but that was only because he lacked the technology we currently have.

[npts2020]

The idea of entropy in the universe seems unlikely to be overturned IMHO.

[ajb]

Wouldn't be the laws of thermodynamics up on the list?

 

There is such a thing as thermal field theory (aka quantum field theory at finite temperature). The goal here is to describe large ensembles of interacting particles in a thermal environment. So it is "statistical thermodynamics".

 

So again, quantum field theory is part of the overall constructions.

[CaptainPanic]

Wouldn't be the laws of thermodynamics up on the list?

 

Agreed.

Conservation of energy is rock solid. I have never seem anyone suggest that this theory needs an addition, or that it is incomplete when you look at lightspeed velocities, lightyear distances or micro-sized particles.

 

Correct me if I'm wrong, and maybe I might re-design some factories.

[ajb]

Agreed.

Conservation of energy is rock solid. I have never seem anyone suggest that this theory needs an addition, or that it is incomplete when you look at lightspeed velocities, lightyear distances or micro-sized particles.

 

Well, it is not so clear how to define energy and if it is conserved in the context of general relativity. (I am thinking globally here rather than locally.)

 

You can motivate why this maybe the case by think about symmetries. Energy is the conserved charge under time translations and momentum the conserved charge under spacial translations. As relativity (both special and general) involve transformations that mix up space and time then energy and momentum are going to get mixed. This is indeed the case.

 

The case of curved space-times then makes this all a little bit more tricky. Particularly when making global considerations.

 

Anyway, what you can do is define energy pseudo-tensors. But unfortunately they depend on the coordinates you use. Not surprising, but unfortunate.

 

In short, energy can be conserved in general relativity. However it will depend on exactly what you mean by energy and conserved.

[Severian]

None of them. Any and ever model makes wrong predictions, or fails to predict things we know are true, so no theory of physics we have is entirely correct and complete.