# String theory



## ereviscale (Jun 29, 2006)

I once watched a nova episode about string theory and i couldnt get anyn of it, well perhaps a little but that is about it. I was just wondering if anyone had any idea of what string theory is. In my life time i have found that this is the most comlicated thing i have ever tried to grasp.


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## littlemissattitude (Jun 29, 2006)

String theory:  Any sufficiently long piece of string will inevitably get tangled up.

Corollary:  The knots in said tangle with be tighter, more numerous, and more difficult to undo the less time you have to untangle them.



Seriously...I don't have the first idea of what string theory entails, although I have heard of it and know that it has something to do with astrophysics.  There are a few people who will be able to answer your question intelligently, and one of them will likely be along shortly.


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## j d worthington (Jun 29, 2006)

On this one, I'm only beginning to understand the concepts to a degree where I feel I'm seeing a little light. However, I'd suggest Hawking's *The Universe in a Nutshell*, if you've not read it. It's one of the more intelligible descriptions I've come across, myself. Others will probably be much more knowledgeable (Chris comes to mind), and may have better suggestions on this aspect of things. But, yes, it is, from my understanding, a rather complex idea, at least in its permutations. Then, once you've tackled it, you've got branes, p-branes, multitheory, etc.... I think even Einstein would have a headache at some point.... but I also think he'd love it.


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## dreamwalker (Jun 30, 2006)

I think the basic idea (which is a pritty beautiful one imho) is that when you see a length of string, it appears 1 dimentional. Look closer, and you see if has width and depth - volume and a existance through time (4 dimentions).
And that idea lends it's self to the idea which you may have heard that there are dozens(?) (at least 10 atm away) of dimentions, most of which are so tightly bound up from our perpective, that they seem to be invisible.


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## Milk (Jul 1, 2006)

I believe that its the idea that the basic components of matter are not all point particles. These tiny bits are planc size which is very small. Not being confined to point particles, the tiny bits are free to take on all sorts of wacky and zany shapes like gloppy blobs that resemble pudding.
All this funky geometry ensues.

Also the tension on these strings is immense. The strings twang like a musical instrument. This produces waveforms. An enormous amount of the waveforms cancel eachother out. The scrap notes left over are all matter and fundamental forces. Existance is the leftover waveforms of miniscule vibrating strings.

Skeptics of string theory want solid evidence from experimentation and observation but from what I understand the energies involved to perform an experiment validating string theory would be more the a few galaxies worth.
Some string theorists would maintain that the chart of Elements is the evidence since the math of string theory apparently lines up with it.




Thats my feeble understanding of it. *The Elegant Universe* by Brian Greene is an excellent book about string theory.

What confuses me is I thought that planc length was the very limit of smallness, and I think string theory suggests that there are spacial dimensions smaller then planc length. But I thought nothing could be smaller then a planc length. >.<


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## j d worthington (Jul 1, 2006)

I've said it before, and I'll say it again (until someone tells me to shut up, that is): With stuff like this to think about, who the heck needs recreational drugs? Or any drugs (with the possible exception of a rather large aspirin -- oi, my head!!!)


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## Locksmith (Jul 20, 2006)

Milk said:
			
		

> I believe that its the idea that the basic components of matter are not all point particles. These tiny bits are planc size which is very small. Not being confined to point particles, the tiny bits are free to take on all sorts of wacky and zany shapes like gloppy blobs that resemble pudding.
> All this funky geometry ensues.
> 
> Also the tension on these strings is immense.


 
Just reading a book called Galileo's finger by Peter Atkins, which deals with a number of scientific discoveries/theories in a pretty straightforward way. I wont even try to explain string theory because I can't pretend to understand it fully (and Milk has done a better job than I could). However, the two bits of information that just amazed me were: 

size: if the nucleus of an atom were magnified to the size of the earth, each component string would be around the size of the original nucleus, and

tension: the tension is the equivalent to hanging the weight of a trillion suns from the string.

Blows my mind!



			
				Milk said:
			
		

> What confuses me is I thought that planc length was the very limit of smallness, and I think string theory suggests that there are spacial dimensions smaller then planc length. But I thought nothing could be smaller then a planc length.


 
This slightly confuses me too - if Big Bang theory is correct, there must have been a time (which I believe is referred to as the Plank time), before which all of the matter in the universe was crammed into a space smaller than a Plank length...


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## star.torturer (Jul 20, 2006)

you might get a better idea from physics forums


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## dustinzgirl (Jul 20, 2006)

Brian Greene's book is much better than Hawking, but that is because Hawking seriously creeps me out. I think he is the anti-christ. Anyways. On to string theory:

Simplistic and sticks mainly to Superstrings:

http://www.sukidog.com/jpierre/strings/basics.htm

With cool puctures and its pretty much accurate. 

A science article on it and opposers:

http://www.physicspost.com/articles.php?articleId=25

Basically this is a quantum physics theory only that uses a lot of crazy butt math, but in short it states that the strings exist in the 4th dimension and up, which is why we can not see them, and these strings have a resonance. Meaning, they are always trembling--like playing telephone with a cup and string?--and transforming/transferring energy--in as many as 26 dimensions that we can assume to calculate with our meager science.

So what does string theory do, if we can not touch it or see it or even  more than assume to calculate it? String theory fills in theoretical holes in quantum physiscs, specifically to the behavior of smaller particles--quarks, fotons, ect...

The short of it is, all things are connected by supra-dimensional mathematically expressed energy type thingies that we can not see, feel, record, or touch.

The whole thing, while having some basis for wicked future research (I'm thinging, sub dimensional and super space travel) is only based on ASSUMED mathematics. Nothing can be proven, not even the formula they use.


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## Milk (Jul 21, 2006)

As Dustingirl mentioned, Brian Greene, who was the main guy speaking on that Nova show (which I just watched last night) wrote a really good book about string theory called *The Elegant Universe*.

It had a lot of decent pictures, I love it when illustrators attempt to scale otherdimensional spaces.

On a side note for an interesting read that completely relates to string theory but written in the victorian age, I highly recomend. Edward Abbot's *Flatland : *A romance of many dimensions.

Not so much string theory itself. But once you read the short story.. it just might be possible to catch on to the idea of what extra dimensions would be like... though its tough to explain.


Oh yeah and I mistyped  planck as planc.


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## dustinzgirl (Jul 21, 2006)

I want to see in 26 dimensions. I wonder if there are space beings that can. That would be so totally uber-cool


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## the smiling weirwood (Jul 21, 2006)

What would these other dimensions be?


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## dustinzgirl (Jul 21, 2006)

the smiling weirwood said:
			
		

> What would these other dimensions be?



As far as I understand it, there are 12 or 13 mathematically proven dimensions, and the others are theoretical.....Its like looking through a kaliedescope, but all atop each other. Our eyes and brains can not process that, at least not in this stage of our evolution. But they can prove and theorize using mathematics.


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## the smiling weirwood (Jul 21, 2006)

I wonder if our species will survive long enough to evolve to that stage....


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## Milk (Jul 22, 2006)

the smiling weirwood said:
			
		

> What would these other dimensions be?


 
They're very small. 

And they are the dimensions that for whatever reason didnt expand along with the three familiar ones during the big bang.

They are Planck length size or there abouts." I say thereabouts because:

Planc length is the very limit of small. In the Nova show Briane Green described the distance as "If a proton was the size of the solar system, a string in comparison( which is a planck unit of size from what I understand) would be the size of a tree"

However in his book, I remember reading that a planck length is "If a proton was the size of the known Universe, then planck length would be the length of a small dog." Maybe my memory isnt so good.

The size part is crucial. Because what this means is...
well you see particle accerators are used kind of like gigantic microscopes, and the _resolution_ of the best particle accerators isnt anywhere near good enough to percieve strings. And its just concievable that they never will be. No matter how expensive or sophisticated.

Bah im sidetracked so ill use an analogy to explain what I mean about resolution

Imagine trying to create a portrait of your friend by throwing coconuts at him and looking at where they landed after hitting him. You would learn his features depending on what parts of his body the coconuts hit and capturing them afterwards... The coconuts lieing on the ground around him on the sandy beach that you just hit him with would form a picture of what he looks like-- in negative--at poor resolution.. very poor.


Kind of how bats use sonar to gain an image of their sorroundings they bounce sound off stuff and listen to it bouncing back.

Except what you have are coconuts.

Not very good resolution using coconuts is it?
Try using golfballs ?
"still not a very good fascimile eh?"
try mothballs.
"Getting better?"
Now bb pellets.
"Wow I can almost see eyes a nose and teeth"
Now try tiny blobs of ink
"nice portrait, but you can get more accurate keep trying" 
Using photo lithography--which is to say molecules
"Photo realism woohoo, further resolution?"
Make a portrait out of protons
... you get the idea. 

Okay. Now try to get an image of him by throwing the Andromeda Galaxy at him.


Capturing a picture of a string using protons, or even electrons, is the same deal. All we have are really _big_ blocks to work with. Stuff like protons and electrons.

That's the challenge of seeing at the resolution of planck length, and thats where string theory says these extra dimensions are found.

So as exciting as they may sound, its really hard to prove or disprove they exist since it will be a while, if ever, before we can see them.


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