Explain string theory to a biology student

[MoMo]

As the title says I am a biology student, I want to understand string theory and all the controversy behind it.

 

String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles), I understand what this says, but I don't understand how this would apply to real life or how would change the current understanding of our universe. Compared to our current understanding of the universe, what changes does string theory cause to our current understanding

 

Please try to explain in general terms, with minimal use of complex terminology.

[Klaynos]

Well I'm not a string theory fan at the moment.

 

Some points of note:

 

It's not a theory.

It's not one idea, and most theorists working on it have a completely differnt view to all of the others...

 

Have a read of http://en.wikipedia.org/wiki/String_theory it probably wont help much but it's more than I can do, sorry

 

Are you well versed on quantum mechanics and relativity?

 

One reason why it's so controversial other than not being a theory is that it's not currently testable in any way what so ever. This annoys alot of physicists as we like things we can kick...

[MoMo]

Well I'm not a string theory fan at the moment.

 

Some points of note:

 

It's not a theory.

It's not one idea, and most theorists working on it have a completely differnt view to all of the others...

 

Have a read of http://en.wikipedia.org/wiki/String_theory it probably wont help much but it's more than I can do, sorry

 

Are you well versed on quantum mechanics and relativity?

 

One reason why it's so controversial other than not being a theory is that it's not currently testable in any way what so ever. This annoys alot of physicists as we like things we can kick...

 

I read the wikipedia link already, and if I was very familiar with quantum mechanics, im sure it would help.

 

But i have another question. Why was the string theory developed? does it explain certain aspect of the universe better than our current model?

[GutZ]

I think its to unify all the forces into a single "theory". I think there are still other aspects the current model doesn't have an answer for, but the biggest is incorpating gravity into the mix.

[Klaynos]

The reason I asked about relativity and QM is because they have certain issues that it is very difficult to unify them in certain circumstances (including some gravity situations) string theories are supposed to deal with this.

[fredrik]

As the title says I am a biology student, I want to understand string theory and all the controversy behind it.

 

Please try to explain in general terms, with minimal use of complex terminology.

 

Loosely speaking, string theory is an attempt to answer some questions about how different forces in nature are related. For example, in cases where the quantum effects and effects of general relativity are both supposedly significant, there is currently no satisfactory model.

 

I you have zero background in QM and relativity I think it could be difficult to grasp because the first, and by far, the most important step is to understand and acknowledge the questions string theory is trying to answer.

 

I think there are many isssues with string theory, both fundamental question that regards serious philosophical and logical issues, and then other technical or mathematical consistency issues.

 

Some objections are that "string theory" can not possibly be a fundamental theory because it's based ignores some of the more important issues. Some people seemingly may find it acceptable to dismiss such issues and metaphysics. Or some thing that "in the other end" string theory will "mature" and there will be a reformulation that removes this issues. If you like it or not depends on what philosophy of the "scientific" method you have.

 

Of course, one should give people a break, because any theory may start out fuzzy and inconsistent... by my main issue with string theory is how one could have allowed the most fundamental issues to remain.

 

In my personal view, which I think is share by many others, I can't see the good "scientific method" in the string theory project. It intuitively rejects my philosophical ideals from step 0.

 

/Fredrik

[H2O]

i am also baffled by string theory/idea and have questions on my own but i think it was developed by scientist to combine the quantum(small) and relativistic(einstein's,big oh very big) to what they call a "unified theory of the universe".

 

p.s. i dont have enough idea of string theory itself by concept what really string theory is?

[ajb]

String theory was originally discovered by trying to describe hadron physics and not as a unification scheme.

 

When gauge theory took over string theory fell out of fasion.

 

It was ressurected when it was shown that the string spectrum must contain a graviton-like state. Also, it was show that such theories are good quantum theories, i.e. they suff no anomalies (provided we work in higer dimensions).

 

For details pick up any good book on string theory. I suggest BUSSTEPP Lectures on String Theory by Richard Szabo, which has a good but short historical overview.

 

On a personal not, I notice a lot of "string bashing" going on from people who openly state they don't understand much about string theory. Is this just jumping on the bandwagon?

[CPL.Luke]

it may be that we are jumping on the bandwagon a little bit, or it may be that we have been convinced by the people who write on string theory that the theory doesn't make a whole lot of sense as a physics theory in comparison to other theories that have been developed.

[fredrik]

I'm not sure to whom you refer but I speak only for myself and while my general philosophy is to encourage diversity and multiple attempts I personally never liked the string theory thread. I am not a string expert but I am capable of drawing limited conclusions from what I know of it, and on that I base my actions for best economic use of my resources in the future. I see much better options that I put my energy into. Of course, what is the best option for me, is not the best option for everyone - to each his own. So we do not really have an obvious contradiction here. I have posted a bit here to enter a brief communication with other minds. New ideas and experience is healthy. The proof is in the survival and success.

 

Also more importantly I pose my own questions, and the string theory thread as I've currently seen it simply doesn't answer my questions, no matter how good it may seem to others. I look for more than an mathematical exploit, but that's just me. I do not need to convert to a string expert to hold this opinon. There are possibilities if string theory are radically reformulated... that is the end where I by definition do not have sufficient info. I am open for suggestions when they come, if others do the work. I work on my fave leads, and others on theirs, just the way it's supposed to be.

 

I think one could also decompose theories in several aspects. First there is the starting points and priors. Ideally this should be cleanly posed axioms, methods or some general unavoidable assumptions. This is an important parts and contains some philosophy and possible "metaphysics". Then ontop of that comes the theory with implications, theorems and applications. Before I find it motivated to invest too much time (of which we humans do not have alot) in something, I judge the starting points or the philosophy first. From what I can see here string approach seems pretty weak. More than a philosophically well formulated and generic approach, it seems more like something that started with a what if game of, what if particles really are strings... then the implications of that are worked on in a mathematical sense, then adding various consistency constraints along the way... I am sorry but what kind of procedure is that? The impressing part is the complex math, but from a philosophical point of view there isn't much new at all? At any rate I don't see it.

 

I really don't consider myself more stupid than anyone else. I have a physics/math education, and have spend some time pondering about similar things it's just that I took a 10 year break recently and just started to resume these projects a few weeks ago because I found a new hope. I don't get payed to do anything so I work slowly. This is why I "just talk"... I am still working from scratch and have some stuff left to do before I am on to the next step.

 

I keep the possibility open that I am still just ingorant and miss the whole point, and in that case I offer my apology and hope that my "ignorance" will be my saviour

 

/Fredrik

[Royston]

On a personal not, I notice a lot of "string bashing" going on from people who openly state they don't understand much about string theory. Is this just jumping on the bandwagon?

 

In some instances, yes, it is jumping on the bandwagon (from anyone who appears to have very limited mathematical or physics knowledge.) I've admittedly stated my opinion on string theory, pretty much for the same reasons Klaynos stated.

 

For some of us (speaking for myself), who are in the middle of a degree and who do outside reading, it's more a case of direction. Although I find string theory as fascinating as any other theory, my position is that I need to know what is worth spending my time on with regards to background reading et.c. Any mathematical models that have been developed through string theory, that are useful elsewhere can be tackled when needed, but I'm not going to start treating string theory as an all encompassing idea (which is the problem I personally have with it) when treated as such, it fails to agree with some pretty fundamental principles. I'm sure there's some incredibly useful formalisms that can be applied elsewhere, and this is how I personally view string theory.

 

So yes, it is a bit rich stating an opinion on a theory that you have very limited knowledge on, but I think this rises from confusion as to why it's persued as a possible 'answer to everything.' Personally, I'm taking a back seat with cutting edge physics, because I'm more interested in getting my maths up to speed, so it'll be several years before I can state any meaningful opinion on this kind of subject. (So basically take or leave what I said, it's just how I feel about string theory at present.)

 

EDIT: Just to add (with regards to the first paragraph) I wasn't implying that Klaynos had limited knowledge...because that's clearly not the case. Sorry, it was rather clumsy writing.