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Superstrings and M-theory

Everyone vote in the Democracy of Branes!!! (more later... just like everything else, eh? :oP)

As most of you know, I am **oBsSeSsEd** with these theories. This site is going to take a while for me to put up well, though, becuz Im not very good at putting them into... well, english. And giving a good explination in an understandable form without continuously running off on side tangents. For a really excellent, well-explained walkthrough of superstring theory, plus background info on General Relativity and Quantum Mechanics (which u need to understand to get why Superstring theory came into being and a lot of factoids and such behind it), and the latest formulation of it, M-theory, I would recommend The Elegant Universe by Brian Greene (great quote in the book: "Thats great, but I knew it would work. Wheres my beer?") You can borrow it from me, if I see you at school or any other random location. And just as a disclaimer/credit giver or whatever, a lot of stuff from the following is taken from the Elegant Universe, simply because it's probably the best, most concise or w/e book ive found on the topic, and it has lots of good examples and stuff too. And there's probably stuff I use in here that came from it and lots of other books ive read but couldnt remember where i learned it from, so theyll just have to remain creditless... but I have yet to do any real research of my own into the topic (but i will, i can assure you!!!), so this all comes in some form or fashion from other sources. Lalala, thats enuff of a disclaimer, dont you think?

Superstring theory is a great candidate for the GUT (nice acronym, wot? it stands for "grand unified theory"); as yet it is the only one that hasnt been torn apart by experiment. But thats partially due to the fact that most of its predictions either arent currently accessable with today's technology, or were already known when the theory was put together.

Dualities
according to M-theory, all 5 versions of superstring theory are dual, which is utmostly awesome cuz now its just one theory instead of 5. thank you, edward witten!
its thanks to these reali coolio dualities. first kind of linking-theories duality is radius-radius reciprocol duality. that is, when a curled-up dimension is a specific size (say S) in one string theory, then its 1/S in one of the different theories. The theories that are dual in this manner are Heterotic-E and Heterotic-O (som1s dad *coughs and glances towards weston pointe* along with a coupla other random princeton professors were the ones who wrote the paper showing how the original non-supersymmetric [aka bosonic] string still worked for counterclockwise vibrations, so could be combined with the superstring for clockwise vibrations and would be fine; they also showed that since the bosonic string needs 16 more dimensions that they had to be curled up in one of two ways~ one version is Heterotic-O and the other is Heterotic-E; funni considering they only have it down to a coupla thousand [or actually, infinate considering theres deformations that you can do to these "Calabi-Yau" shapes that doesnt change much about them but does impact their implications on the physical universe] possible formations for the extra 6 dimensions that superstrings need) and type IIA and type IIB strings are also dual in this manner. the other type of duality has to do with the string coupling constant, which means how likely it is that a couple like ::censored:: here will stick together. oh wait, no it means how likely it is that two strings, after running into each other once, will continue to combine and split. for the string coupling constant, we have another inverse relationship where C (the coupling constant) in one theory is equal to 1/C in another theory. The theories that are dual in this manner are type I strings and Heterotic-O strings, and type IIB strings are dual to themselves. but whaz reali wierd is for Heterotic-E strings and type IIA strings, when the coupling constant is above 1, an extra dimension appears! for type IIA strings, they expand to innertube-like shapes (mathematically known as a "torus", like the surface of a doughnut), and for Heterotic-E they expand to ribbon-like shapes.

Special Relativity
Ah yes, Einstein's first major revolution...
Just about everyone's heard of the famous little equation, "e = mc2," but do you know what it's really about? No? Well, that's too bad. It'll come up later, don't worry *pats you on head*. A very important... item... that lies behind both Special and General Relativity, and what basically gives them their name, is called the Principle of Relativity. The Principle of Relativity is simply this: whenever speed or velocity of any object (anything, really) is being discussed, it must be specified who or what is doing the measuring, because from different points of view these can be radically different. Basically: motion is relative. Wow, special relativity seems really simple so far, doesnt it? Of course, the principle of relativity is really hard to actually fit into your brain functioning, considering how used to thinking in absolute terms we all are. "The car is going at 60 miles per hour" seems like a pretty legitimate statement, doesnt it? Well, its not... when we're standing here on nice ol' stable earth, saying that seems perfectly fyne, but thats because the ground under our feet always can serve as a reference point, and we assume that its perfectly stationary. So when you're talking about the car, you're actually saying "From the reference point of the ground, or any observers motionless in relation to the aforementioned ground, the car is going at 60 miles per hour." Mouthful, eh? Small wonder we normally dont bother sticking all that in.

Good Outside Sites on:
Superstring Theory
M-theory
Einstein's Relativity Theories This is actualli his book online... so there's a lot of mathematical junk pulled in and such, but if you can slog through it its definately worth it.