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String theory

Technically string theory has been shown to be wrong. Superstring theory is what is talked about now, which includes concepts from supersymmetry in addtion to string theroy. Not to be picky or anything :P

Superstring theory does make predictions that can be tested at the next generation of coliders, starting with the LHC at CERN in 2007 (hopefully). The main problem is that there are actually many different string theories, may of which make very similar predictions. So while it may be possible to get evidence for string theory in general, it will be very difficult to pick exactly which one to use.

Interesting link though. I always like seeing how people try to represent multiple dimension on 2D surfaces. I always have enough trouble just drawing 3D things. :)
 
Oh, nothing wrong with being picky. I like to know what's going on. I had forgotten the "Super" had been attached to "string" in the theory. :)
 
Well, I watched further. Eesh. They pulled out that "collapse the waveform by MERELY observing it!" garbage. I'm SOOO tired of that being used by weirdos wanting to claim stange things.

:mad:
 
Not interesting at all. Coincidentally, a friend of mine sent it to me last week.

He develops a model where the higher dimensions merely cover the different possibilities of lower dimensions. I.e. the 5th dimension contains the potential different lives we might have, the 6th dimension is the possibility to move around in the 5th dimension, etc.

This model has nothing to do with a grand unified theory and is totally pointless, other than having entertainment value at cocktail parties.
 
Cuddles said:
Technically string theory has been shown to be wrong. Superstring theory is what is talked about now, which includes concepts from supersymmetry in addtion to string theroy. Not to be picky or anything :P

Superstring theory does make predictions that can be tested at the next generation of coliders, starting with the LHC at CERN in 2007 (hopefully). The main problem is that there are actually many different string theories, may of which make very similar predictions. So while it may be possible to get evidence for string theory in general, it will be very difficult to pick exactly which one to use.

Interesting link though. I always like seeing how people try to represent multiple dimension on 2D surfaces. I always have enough trouble just drawing 3D things. :)
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I thought M-Theory had unified all that.
 
TobiasTheCommie said:
I thought M-Theory had unified all that.
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Sort of.

Most of the superstring theories (hereafter referred to as just string theories) have what's called a "coupling constant". Basically, the value of this constant determines how likely multiple interactions are with particles. I can go into more detail if you want, but that's not really important.

M-theory developed when it was noticed that some of these string theories, with the right coupling constants, would produce identical results. For example, Hetrotic A with a low coupling constant would give identical results as Supersymmetry with a high constant (that may not be a correct relationship, but gets the idea across).

So M-theory combined all of these into onr framework. By manipulating certain aspects, you can "drop out" the component theories (much as SR can be gotten from GR when accel=0). However, the question is whether M-theory actually corresponds to our reality. There are several possibilities being considered:

1. One of the string theories is a description of our universe, and M-theory is something else. M-theory is thought by some to be an artifact, by others to be a possible description of all possible universes.
2. M-theory describes our universe, and the various string theories are all special cases.
3. It's something else entirely, and we're wasting grant funds.

So yes, M-theory has unified that, but that doesn't mean that the theories it unified are invalid or out-dated. None of these has been able to be tested yet, so it's a toss up among them.

Disclaimer: I am not a physicist. Actual use of any of my statements in an attempt to control reality releases the author of this post from any and all liability. Use of this information to develop worm holes, particle accelerators, or destroy the fabric of space and time are solely the responsibility of the reader. Also, any actual physicist with actual knowledge may, at any time, offer corrections to this information; the author retains the right to change this information at any time, so as to appear more knowledgeable and less wrong.
 
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Ah, i thought it was 2.. and i thought that was definet.. thanks for telling me i'm wrong, i just learned something :D
 
I just read through "Paralell Worlds, by Michio Kaku. This book is primarily geared to the layman, and goes through the history and current state of string theory. (or M-Theory or Superstring theory or whatever...)
Even though geared to the layman, concepts such as multidimensional space, infinite universes and so forth are a bit heady.
Kaku notes the problems and shortcomings in the theory, and points out that the Large Hadron Collider and a new observaional sattelite going up soon may provide some observational evidence for the first time.
 
I've read one of Kaku's books, "Hyperspace" I believe it was. I've always been partial to Brian Greene though for the physics. His "Elegant Universe" gives an excellent run-down of theories, and talks baout the string theories and how they developed. It's set up to get a brief, easy overview, a more detailed layman's understanding, or (if you go into footnotes) to give some of the mathematics and equations.
 
Huntsman said:
I've read one of Kaku's books, "Hyperspace" I believe it was. I've always been partial to Brian Greene though for the physics. His "Elegant Universe" gives an excellent run-down of theories, and talks baout the string theories and how they developed. It's set up to get a brief, easy overview, a more detailed layman's understanding, or (if you go into footnotes) to give some of the mathematics and equations.
Click to expand...

Sadly only seen the PBS... yet :D
 
TobiasTheCommie said:
Sadly only seen the PBS... yet :D
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I think it'd clear up a lot and answer some questions you have. He gives a good treatment to worldlines and light cones, which I saw in another thread here and it seemed you had a bit of trouble with. They aren't too difficult, but hard to conceptualize. Greene does a good job with them.
 
thanks, i'll see if i can get a hold of the audio book( for this kinda stuff i prefer to listen than to read)
 
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