# String theory in one sentence please!

1. Oct 12, 2009

### Entropee

My teacher told me that in my essay I need to briefly describe string theory (because I'm talking about how the LHC is a good test for string theory) and by briefly she told me 1 sentence.

If anyone could tell me how THEY would describe string theory in 1 sentence that would be much appreciated!

-Gavin

2. Oct 13, 2009

### tom.stoer

I'll try it:

String theory tries to construct a supersymmetric framework in 10 (11) dimensions from which all known elementary particles and interactions including gravity emerge (uniquely) from the modes of an one-dimensional, vibrating string.

The "trial" is bold bevcause up to now they did not succeed; "uniquely" is in brackets because there are indications that the theory is by no means unique; some string theorists try to find a selection principe, some others simpy believe in the anthropic principle; "11" is in brackets because there are indications that the theory has a dual description in 11 dimensions; I leave out certain subtleties like higher-dimensional objects, p-branes etc.

Let's discuss it ...

3. Oct 13, 2009

### Entropee

Heh, thanks Tom, the only problem with yours is it's too complicated for my class. I have been coming up with things along those lines but I realize I have to "dumb it down" a lot, considering it's english class, not physics class haha.

Thanks though, I might use the part about particles and interactions emerging from different dimensions.

Last edited: Oct 13, 2009
4. Oct 13, 2009

### Demystifier

Let me try:

According to string theory, elementary particles are not really pointlike, but have a shape of a short string, too short to be visible with present technology.

Is that dumb enough?

5. Oct 13, 2009

### Bob_for_short

String theory is another failed attempt to describe everything without any experimental background.

6. Oct 13, 2009

### Staff: Mentor

Don't we love humanists?

7. Oct 13, 2009

### BigFairy

Thats a bold statement.

8. Oct 13, 2009

### MathematicalPhysicist

And as time passes by, it seems more plausible.

Besides, every physical theory is a failed attmept to describe phenomena eventually.

9. Oct 13, 2009

### Bob_for_short

Not to that extent.

Let us look at the Newton's second law: ma = F. It is a generalization of many experimental data. Look at the Hook's law: F = -kx. It is also an experimental fact for elastic bodies. Remember PV=NT, I=U/R, q=-λT (for heat flux), etc. Each physical law has its domain of application where all involved letters are physically meaningfull. Another matter these laws are not universal, they all have limited ranges of validity.

The usual geometry is a generalization of experimental facts too.

It is a big mistake to think that one can start from ungrounded postulates or axioms and obtain some reality. What is obtained in this way is mathematical sequences of mathematical postulates, nothing else. String theory is just a mathematical exercise with big but unfounded claims. No wonder it resulted in nothing physical.

Last edited: Oct 13, 2009
10. Oct 13, 2009

### Dmitry67

1 Yes, if we look retrospectively.
But TOE, by definition, should not be limited to any domain

2 It is an exact program of MUH, called "physics from scratch"

3 mathematics IS physics!

11. Oct 13, 2009

### Bob_for_short

So let us force the Nature to obey our mathematical fantasies ?

12. Oct 13, 2009

### Dmitry67

I don't want to touch (again) the MUH, but at least agree that when we talk about TOE we must be ready that it will be a very final step in a sequence of the infinite reduction.

13. Oct 13, 2009

### Bob_for_short

So we observe a rush of geniuses: who first will guess the TOE. It is very near! One more patch and here it is!

14. Oct 13, 2009

### Dmitry67

YES

15. Oct 13, 2009

### Bob_for_short

And I do not like to fool myself.

16. Oct 14, 2009

### Chronos

String is a purely mathematical attempt to model reality. It is not provably wrong [and may never be], but, empirically unsatisfying thus far. It explains some observations, mostly at the quantum level, but otherwise has no compelling observational support.

17. Oct 14, 2009

### suprised

What a nonsense. Of course string theory is built on physical principles. Only because most people don't understand the mathematical language in terms of which these physical principles are formulated, they confuse it with "pure" mathematics. Such comments just reveal ignorance.

18. Oct 14, 2009

### Galteeth

19. Oct 14, 2009

### Demystifier

It is not more "purely mathematical" than, e.g., general relativity.

20. Oct 14, 2009

### MathematicalPhysicist

That's what I meant, we first were accustomed to the notion that Newton's laws describes everything, but with time we've seen that it's limited in scope, and then it was substitued with Einstein's GR, and thus only mathematical theories are timeless as opposed to physical theories which change with time.