String Theory

JacksColon · Post by **JacksColon** » Sat Nov 03, 2007 1:01 am

So, I'm not a physics nerd..in other words, I suck at math and will never wrap my head around the equations in theoretical physics. But, I love the ideas and concepts, especially with string theory....what do you guys know about it? what do you think? etc...

I've been so guest lectures on the subject by some of the leading scientists and I've also read great books by people like Brian Green...just wanna know what you guys think

Xyzzzy · Post by **Xyzzzy** » Sat Nov 03, 2007 1:02 am

I'm at the same point as you with this topic. I find it very interesting I want to see how this thread turns out.

redneck · Post by **redneck** » Sat Nov 03, 2007 1:02 am

Xyzzzy wrote:I'm at the same point as you with this topic. I find it very interesting I want to see how this thread turns out.

ditto

Stormprobe · Post by **Stormprobe** » Sat Nov 03, 2007 1:14 am

Umhh Xyzzzy lieks it it mustb e good. First explainw hat string theory is please ?

XemnasXD · Post by **XemnasXD** » Sat Nov 03, 2007 1:17 am

...yes, I too wish to see how this topic turns out

*sarcasm* for ppl so interested in the topic you guys sure don't seem to know anything about it...

Xyzzzy · Post by **Xyzzzy** » Sat Nov 03, 2007 1:17 am

go wiki it
and read that you will get a general understanding of it

Stormprobe · Post by **Stormprobe** » Sat Nov 03, 2007 1:20 am

Wow. i wiki'ed it i too know want to know the outcome of this thread.

Reise · Post by **Reise** » Sat Nov 03, 2007 1:22 am

I read about it a little. Sounded a lot less plausible than some of the other theories I've heard of.

redneck · Post by **redneck** » Sat Nov 03, 2007 1:38 am

This thread is dieing im gonna have to use rebirth!!

JacksColon · Post by **JacksColon** » Sat Nov 03, 2007 1:46 am

Think of a guitar string that has been tuned by stretching the string under tension across the guitar. Depending on how the string is plucked and how much tension is in the string, different musical notes will be created by the string. These musical notes could be said to be excitation modes of that guitar string under tension.
In a similar manner, in string theory, the elementary particles we observe in particle accelerators could be thought of as the "musical notes" or excitation modes of elementary strings.
In string theory, as in guitar playing, the string must be stretched under tension in order to become excited. However, the strings in string theory are floating in spacetime, they aren't tied down to a guitar. Nonetheless, they have tension. The string tension in string theory is denoted by the quantity 1/(2 p a'), where a' is pronounced "alpha prime"and is equal to the square of the string length scale.
If string theory is to be a theory of quantum gravity, then the average size of a string should be somewhere near the length scale of quantum gravity, called the Planck length, which is about 10-33 centimeters, or about a millionth of a billionth of a billionth of a billionth of a centimeter. Unfortunately, this means that strings are way too small to see by current or expected particle physics technology (or financing!!) and so string theorists must devise more clever methods to test the theory than just looking for little strings in particle experiments.
String theories are classified according to whether or not the strings are required to be closed loops, and whether or not the particle spectrum includes fermions. In order to include fermions in string theory, there must be a special kind of symmetry called supersymmetry, which means for every boson (particle that transmits a force) there is a corresponding fermion (particle that makes up matter). So supersymmetry relates the particles that transmit forces to the particles that make up matter.
Supersymmetric partners to to currently known particles have not been observed in particle experiments, but theorists believe this is because supersymmetric particles are too massive to be detected at current accelerators. Particle accelerators could be on the verge of finding evidence for high energy supersymmetry in the next decade. Evidence for supersymmetry at high energy would be compelling evidence that string theory was a good mathematical model for Nature at the smallest distance scales.

JacksColon · Post by **JacksColon** » Sat Nov 03, 2007 1:47 am

Now for the "hard" version of that same post:

http://superstringtheory.com/basics/basic4a.html

Silkroad · Post by **Silkroad** » Sat Nov 03, 2007 2:03 am

redneck wrote:This thread is dieing im gonna have to use rebirth!!

don't steal ma siggeh

nightbloom · Post by **nightbloom** » Sat Nov 03, 2007 2:44 am

Umm String theory got bumped for membrane theory/11th dimension. I know a lot of people are still using that term and studying it, but it's already been proven inaccurate.

Jabo · Post by **Jabo** » Sat Nov 03, 2007 3:12 am

Inertia and Grabitational Theory for the win =)

XemnasXD · Post by **XemnasXD** » Sat Nov 03, 2007 3:47 am

sounds like bunk....and even if it were true whats the practical application...

Matrixman__ · Post by **Matrixman__** » Sat Nov 03, 2007 3:54 am

Our understanding of string theory, supergravity, M-theory membranes and their relation to quantum theory is think the understanding of classical physics in the 1700's, there was a general sense of something, but the surface was barely scratched. The potential that M-theory offers are things like sub-space, time travel, anti-gravity, basically eveything you can think of in science fiction plus nearly infinite other possibilities...but seriously, we are like hundreds of years away from mastering "M-theory" (or whatever it ends up being in the end)

honestly, i personally dont see a future in string theory, it seems like they have to keep changing things to "solve" certain impossibilities

IMO, quantum theory offers much more of a possible solution to an understanding of things

P.S. i am sure membrane theory will hit a dead end in time, but considering the complexity of the calcuations involved, it may be a long while before we see anything from this

corkscrew · Post by **corkscrew** » Sat Nov 03, 2007 4:15 am

i still dont get what it is..