Is M-Theory Really a Theory of Everything?

[Curious6]

Hello! I am new here and I've been curious for a while about string theory and M-theory. Taking into account I don't have the theoretical physics background of most posters here (I'm 17), could anybody please explain any of these questions for me:

1. Is M-Theory really a Theory of Everything? What I mean by this is would it really explain all physical phenomena and describe the Universe as it really is? Or is it just a part of a larger theory that encompasses it?

2. When will we know if M-Theory really is this Theory of Everything? Is it a question of improvements in the theory behind it, or is it just a matter of finding significant experimental evidence to prove all of this? Will the LHC of CERN (if supersymmetry is detected) be proof for string theory? Also, do you believe in this decade or the next one the Theory of Everything will really be uncovered, and no more adjustments to it will have to be made?

Thanks in advance to anybody who can help me answer these questions. I really am CURIOUS!

 

[selfAdjoint]

M-theory is "the only consistent theory that contains both quantum physics and Einstein's field equations". So it is a potential candidate for being able to do the Standard Model AND relativistic gravity. That would be a theory of everything according to some, since it would be a combined theory of all four forces (the SM already combined three of them).

But the devil is in the details, and the strengths of M-theory have not yet been successfully focussed on the low-energy realm where present day theory and experiment are, and where the SM and GR live. In fact recently it has been emphasized how difficult it will be to do this focussing. M-theory predicts not only our low energy universe, but also a humongous number of other universes. And they haven't yet discovered any firm physics that will enable them to select just the right prediction out of the noise.

So this is the bar the M-theorists have to jump; devise a prediction that isn't put in by hand, but derived a priori, and which gets us to the particular universe we live in. Only then will it be possible to make predictions that can firmly support or falsify M-theory.

 

[Curious6]

OK, thanks a lot for the information. So, as I understand it now, M-theory predicts that there are an extremely large number of universes, and theorists' main obstacle right now is that they have to find the right prediction for our Universe. Does this mean that all the other universes are equally real or that finally only one option will fit our Universe, which is the only real one out of many possibilities? Also, do you believe the mathematics required for this will take many decades or can be solved in a few years perhaps? Again, thanks for helping me out on these doubts!

 

[Alamino]

There is something I didn´t understand well. Does Self-Adjoint´s answer means that M-Theory predicts that there are more than one universe or that it has many solutions that describe different universes including ours and there is a need to find what is the principle that can select our universe as the only solution among the others?

 

[selfAdjoint]

Alamino, ssorry for the confusion; my bad. The second part of your question "it has many solutions that describe different universes including ours and there is a need to find what is the principle that can select our universe as the only solution among the others" is the right one. The theory produces a signal drowned in noise. Or at least "if there's this much sh*t there must be a pony in there somewhere."

 

[Curious6]

I think I've understood what selfAdjoint has said, thanks a lot, but there's still a small doubt: does this mean that the other universes predicted by M-Theory truly exist or are they just hypotethical possibilities ?

 

[QuantumDefect]

Witten and a couple of other guys have been studying F-Theory lately which has 12 dimensions. I am getting kind of lost with all these theories