String Theory and M Theory

[[Tycho?]]

Spoken as someone who has much experience of string theory?

 

String theory has made zero verifiable predictions. So, it is a lot of fancy math at this point, not really a theory at all.

[ajb]

;337206'']String theory has made zero verifiable predictions. So, it is a lot of fancy math at this point, not really a theory at all.

 

Maybe we will soon be able to test the existence of extra dimensions, observe black hole evaporations, see supersymetric particles, detect (F or Cosmic?) strings in cosmology? String theory also makes some predictions on how GR could be Modifed. Maybe we could observe this one day. All of which could in principle support string theory to some degree.

 

However, I would agree that string theory is not a theory in the strict sence, it is a mathematical frame work to construct theories. In the same way that quantum field theory (of point particles) is not a theory, but a mathematical frame work in which you can construct the standard model.

 

The big problem right now is that string theory does not seem to be unique. This is the landscape problem. String theory has many many solutions all of which "could" be our universe. How to pick the correct one is the question. Before one could make very precise predictions this solution must be singled out.

 

Maybe we are just asking too much of string theory? It provides the best way so far to combine gravity and quantum mechanics, but maybe it is not a TOE. Who knows....

 

But your point can be made of any quantum theory of gravity. Unless we can make observations on the scale of Planck energy we cannot test quantum gravity directly.

 

How to do this, maybe we have to look for cosmological remnents of quantum gravity? See if there is a signal of a specific theory of quantum gravity in the CMBR. It is thought that strings (either cosmic or F-strings) may have contributed to the density fluctuations in the CMBR. Evidence of string theory?

 

Also, as far as I know no other theory of quantum gravity makes predictions/speculations that string theory does/can not. For example, non-commutative space-time on small scales.

 

Untill Planck scale physics is tested no one can rule out or in string theory or any other theory.

[theCPE]

String theory reminds me of chemistry lab........

 

manipulating the numbers, operations, and rounding to inch my data ever closer to the 'expected' values.........

[grifter]

string theory is a disgrace, draining vital funding, resources (not to mention physicists,) from all other areas of physics, thank goodness that the majority of people are beginning to see sense, the disillusionment that String has fueled is finally dissipating, and I couldn't be happier