anything that happens outside the earth, and most of the things there too, i know what it is. a physics major may say my knowledge is incomplete, but when he explains it to you, youre not going to understand.

ever wondered what a quasar, pulsar, hypernova, gamma ray burst or neutron star is? well guess who knows. tminionman. but he doesnt actually want to spend a ton of time at work explaining it to you.

i dont see what one has to do with the other. if i was fully utilizing my knowledge of astrophysics, i guess id be sitting behind a telescope. which would suck.

im at work, i have nothing to do except go on the internet. i like writing about physics. im not bragging. ask something interesting.

huh? are you refering to my mention of tminion? i was merely saying that he knows more than me, but he doesnt want to sit here and explain the entire universe. i do.

theres not much to it. the main difference between classical quantum mechanics and string theory is that in classical, the fundamental particles, protons, electrons, they are tiny points with no visible characteristics other than their influence on other particles.

string theory is an attempt to decribe what they look like. imagine you have a string in the formation of a wave, wrapped in a loop. when the crest of the wave is one inch away from the trough, thats a proton. when that amplitude is half an inch, thats an electron.

one of the weird things about string theory is that its not a one dimensional string on a 3d surface like the strings we are familiar with, but there are supposedly strings of varying dimensions, a 1d line, a 2d membrane, etc. and they wave around in more than 3 dimensions, i think 6 or 7.

these extra dimensions supposedly exist all around us. imagine a worm who lives in a tube. the tube is as big as he is, and in order for him to see, he shoots out a ball that is also the width of tube, and it bounces off of the object in front of him and comes back. he can ‘see’ the universe by counting how long it takes for the ball to come back. his entire world consists of one constantly changing number, the distance between him and his closest neighbor.

this is how we interpret the universe. there are three dimensions, but we only see two (if you close one eye).

back to the worm, if something existed that was smaller than the width of the tube, it could move in all three dimensions. even though the worm can only move forward and backwards, one dimension, anything smaller than the width of the tube is going to be able to move in more dimensions than the worm can comprehend.

since the basic messenger particle that the worm uses is also one dimensional, the ball, the worm is also not even going to be able to see that there is more than one dimension. his entire universe, the matrix that he lives in, is composed of one thing, the distance between him and the worm in front of him. ideas like left and up just dont make sense to him.

according to crazy math and nothing more, thats the world we live in. with 6 or 7 more dimensions “curled up” so that anything smaller than the plank length (the size of a tree on earth if an atom is the universe. something like that) can move about in 6 or 7 dimensions we cant comprehend.

the main reason why string theory was invented is because when a black hole is created, or when the big bang happened, science doesnt have any way of thinking about that stuff. there are two main theories that describe the universe, einsteins relativity explains large scale gravity, and quantum mechanics explains small scale other three forces. when you have lots of gravity in small places, it doesnt compute. black holes and big bangs have infinite gravity according to non-string theories and so dont make sense.

im not sure exactly what conclusions can be drawn from a string theory big bang or black hole that cant be drawn from a normal one. maybe someone else knows.

in the elegant universe by michael greene, string theory also seems to explain time dilation as a result of high speed. something about the string entering the world-perception-time-cone of the observer at an angle. or something. if someone could please explain.

theres plenty more that string theory encompasses.

hyperspace is pure fantasy. there is no reason to think that the curvature of space allows for one section to curl up into another. it is nothing except wishful thinking.

however, some crazy scientisists have predicted, probably wrongly, that a black hole can spin so fast that instead of collapsing into a tiny dot, it collapses into a donut shape.

if you go into a donut, and its big enough or your lucky or something, you can go through the middle of it and the forces will cancel out. when your in the middle of a donut, infinite gravity wont hurt because it pulls on all sides.

then, if we contact some 4d aliens, we can move “flooob” and “dooob” (as opposed to 'up and down), and connect to another point of the universe somewhere. or maybe, the donut blackholes will randomly connect somewhere on their own.

nobody knows the slightest tiniest detail about hyperspace.

The problem with quantum mechanics is that it cannot incorporate gravity, the difference is that string theory can. When we try to put Einstiens equations into quantum mechanics we get non-sensicle answers, we get infinity’s. Quantum mechanics can only incorporate 3 of the four forces, Strong and weak nuclear force, and electro magnetism. What string theory does is unify all of the four forces, in a simplistic, and elegant manner. String theory seems to automatically incorporate all of the other theory’s . String theory doesn’t change quantum mehcanics, it incorporates it with Relativity.

What I mean by automatically, is that when doing equations in string theory, and not previously assuming the other theory’s, the other theorys automatically pop up. This is the strongest attraction to string theory, is that they found when they extended the original Kaluza-Klein model to (N) dimensions that the Yang Mills Feild theory(the key to the standard model, which explains how sub atomic particles interact) automatically popped out!!! as if by magic. The yang mills feild was found virtually by trail and error for over 80 years!!! And it just automatically pops up in string theory. Also by doing calulations using only the self consistancy constraints alone it pops out precisley Einstiens theory of Gravity. So basically without previously assuming the equations, The field theory’s that compose the entire scientific ascent of man within the past two millenia, automatically pop up in string theory!! String theory wasn’t tailor made to fit the theory’s, the theorys are automatically included!!

Why is it strings? String theory is not some farfetched idea, where someone thought that the world could be described as strings of energy. The origin of string theory really dates back to Reimann back around 1860. Reimann was Gauss’s protege, and gauss had him do a paper on Eucilid geometry. At the time both Reimann, and Guass had stong reservations about our world only being 3 dimensional, but to think of other dimensions was unheard of. Reimann held a public address, where he basically showed how mathematics became simplified when expressed in higher dimensions. Yet the public view at that time utimately made theory’s which incorporated extra dimensions die off for many years. It popped its head here and there only to die off again and again, that is until Einstien.

Einstien knew the physical properties of Gravity, what he lacked was a mathematical expression. He tried for some time to write the equation yet it was beyond him. Until a friend trying to help him out stumbled upon Reimanns work of some 60 years prior. Einstien found that it was an exact fit. He didn’t have to tinker with the mathematics at all, Riemanns metric tensor just ate it up!! Giving Einstien his equation, and his place in history, and introducing another dimension, space-time.

Future man used an example of the worm, heres another example that I think would be easier to picture. You have a piece of paper which is actually a universe in itself. This universe is called “flatland”, and all of flatlands inhabitants are two dimensional beings. To these two dimensional beings any talk of higher dimensions is strickly frowned upon, its insane!!.
What Reimann did was crumple the paper up, and asked the question what would these two dimensional beings think? His answer was that they would still only believe in two dimensions, yet if they were to try and walk straight across the paper they would be pushed by some unseen force left, right, forwards, or backwards. How would these two dimensional beings go about describing this force? They would use they’re two dimensional mathematics, and find it very difficult.

This is basically what we have done over the past two millenia, is found the properties of the forces, yet we can’t explain them. Why does light travel unempeded through a vacuum? Current physics can’t explain this. In string theory it is because of a vibrating fifth dimension.

Strings were not just arbatrarily picked, its just that the mathematics of higher dimensions gave us the properties of strings. The strings vibrate like any string you’ve seen in day to day life. Like a voilin string, differnent
vibrations create different resonances. In string theory all point particles, are just resonances of a vibrating string.

In the current heretic string theory model, strings rotate clockwise in 10 dimensional space, and counterclockwise in 26 dimensional space. String theory only works when dealing with 10 and 26 dimensions.

Obviously its not crazy math. Critics of string theory do not site the math as the problem at all, they point to the fact that currently it cannot be tested. Its the math of higher dimensions that gave us Einstiens theory of relativity. Without the math we would not have seen one of the greatest breakthroughs of the 20th century.

The reason it can’t be tested is as Futureman said that we do not have machines capable of of testing it. String theory’s home lies at the Planck energy, this energy was only released at the instant of creation itself. So string theory is basically a theory of creation, and therefore cannot be tested directly. We would need a machine capable of producing energies trillions of times larger then what we can now create in our atom smashers. In string theory, at the beggining of time our universe was a perfect 10 dimensions, but this 10 dimensional universe was unstable, and so the big bang happened literally creating a tear in space time, four of our dimensions expanded rapidly, while the other six curled up.

And there really is no reason why string theory was invented, string theory more or less was fell into ass backwards. The reason we have string theory today is largely Due to Riemann, a letter sent to Einstien by Kaluza which Incorporated his equations along with Maxwells in a fifth dimensional model using Riemanns metric tensor, and the fact that the mathematics become simple, and elegant when expressed in higher dimensions. The reason we have string theory today, is that we have as yet failed to create a unified theory, and string theory does this automatically with grace, and ease. The problem is that we can’t test it.

I just recently bought the elegant universe by micheal green, but have not read it yet. I’m going to read it next week, so when I come to the explanation of time dilation I’ll come back and post what Greene had to say if someone else has not already posted it.

Anyways the basic attraction to string theory is that, as Reimann showed back in 1860, mathematics becomes simpler, and “elegant” when calculated in higher dimensions. String theory just seems to eat up all the other theory’s, they are automatically included.

Hyperspace is just a result of string theory. Hyperspace is basically defining that we live in a world of higher dimensions. If string theory is right, then in fact we do know a great deal about how hyperspace universe would function. Our minds can’t visualize higher dimensions, yet the mathematics of it our relativly simple.

One last note about string theory, is that there is some hope in testing the theory indirectly. So it is not a lost cause in this respect at all. Think of the mathematicians, and scientists in the 19th century who thought that a 4 dimensional world was complete nonsense. Then Einstien came along!!

The reason why Green’s book is entitled the elegant universe, is simply because the mathematics of string theory are just that elegant. We have various complex models, such as quantum theory, that are very ugly. Quantum theory really doesn’t incorporate the other theory’s very well. The three theorys that are incorporated in quantum theory alone all have they’re own inherent symmetry. What Quantum theory does is splice these three symmetrys together to make one theory. Its like a jiggsaw puzzle, if you couldn’t figure out the currect configuration you could always use tape!! This is what quantum theory does, and the mathematics are hence very ugly. When we add extra dimensions, the mathematics easily incorporates all of the theorys, and creates a supersymmetry!! Thus supersrting theory.

Peter Freund, a leading physicist in string theory gave this analagy.

“Think of a cheetah that has been captured and thrown into a miserable cage in a zoo. It has lost its original grace and beauty, and is put on display for our amusement. We see only the broken spirit of the cheetah in the cage,not its original power, and elegance. The cheetah can be compared to the laws of physics, which are beautiful in their natural setting. The natural habitat of the laws of physics is higher-dimensional space-time. However, we can only measure the laws of physics when they have been broken, and placed on display in a cage, which is our three dimensional laboratory. We only see the cheetah when its grace and beauty have been stripped away”

FM
Knowing everything means you should also have known that QM and string aren’t opopsing theories.
String is merely an attempt to link the standard model of physics(general rel) with the quantum mechanics model.
It seems you don’t know ‘everything’ after all.

Thanks for the explanation, I didn’t ever really look at it until I asked you. I don’t quiteee know about the flatlandss reference, because for an object to be seen separatee from something else, their must be height involved. In other words, the 2d image wouuld have to displace parts of the paper to truly be 2D.

Dr Sat was right: string theory is an attempt to pull quantum and classical physics into a TOE (Theory of Everything)

FM or Rounder (or anyone else): How many fields are required to create a universe like ours (I know this part). If you know, do you know the names of these fields? (I have no idea of this part)

Wow thanks I didn’t even notice it was my 100th post. First off let me say that in posting a reply in this thread I by no means am saying “I know everything”, far far from it. I just replied because I am interested in string theory, and do know a bit about it.

Anyways… how many fields to create our universe? Well we have four well defined feild theorys which describe the four forces.

Einstiens Gravitational Field- gravity
Maxwell’s field- electro-magnetic force
Yang-mills field- weak and strong nuclear force

Einstiens theory of relativity pointed at a moment of creation. The big bang. Data that we have uncovered concerning backround radiation, or black body radiation, has agreed with this theory precisly. Also the chemical distrubution that the big bang theory predicts is almost in exact agreement with the theory. Although Einstiens theory inevitaibly lead us to the big bang, when taken to its limits Einstiens theory of Gravity breaks down, at incredibly small distances, and large energy’s. Qauntum effects take over. So at the instance of creation it was basically the Strong force that was in play, then shortly after the weak force, and Electromagnetism would have began to occur. And it in the time frame of minutes gravity then would have became strong enough to create stable nuclei, and Einstiens equations would hold.

So its really the Three fields, that describe the four forces that would create our universe.

Well I hope the flatland reference worked for the analagy purposes alone. Anyways, just draw two seperate lines on your peice of paper, to a flatlander those would be two seperate objects.

I guess the obvious fields required to create a universe like ours are the 3 dimensional fields, time and space, gravity, electro-magnetic and the strong + weak nuclear fields but then what? According to an interview I saw with the director of CERN (canâ€™t remember his name) he was excited that there were only 37 fields needed.

Some info can be found by searching â€œcern 37 fieldsâ€ or â€œuniverse 37 fieldsâ€ etc.

I did a search as you suggested, but didn’t really find anything. As far as I know all forces, and explanations of the physics of our universe can be derived from the four forces, and the four feild theorys which explain them. Its why the search for the quantum field theory of gravity, is called the search for the unified theory, the holy grail, as to unify all the known forces in our universe. I’m sure they’re are other field theorys such as Higgs field, but they are all products of the fundamental fields.

I give up… there isn’t much on the web except for the professional articles that pop up using scirus.com and other scientific search engines and I’m not interested enough to search through pages of algebra or Italian to find the answer

On the matter of whether they are subsets of the fundamental fields, I think you must be right. I was just surprised when the director of cern proclaimed that that there were only 37 fields needed to replicate our universe; I thought that was a lot – yet he was making the point that there was ONLY 37.

Back to string theory:
The problem with string theory, as I understand it, is that there’s not ONE, elegant, simple, unifying string theory but 5â€¦. all of which compete with each other, add complexity and more questions. Not quite the unification we were after???

Yeah I believe that there have been many different “string-theorys”, but the basis for them all is relatively the same, physicists often joke saying that when they find the answer then they will call it string theory. There are a couple of problems with string theory. String theory over the past couple of decades has just seemed to evolve, so there were many different theory’s, the current theory as of 2003 I believe is called M-theory. The big problem with string theory is that no one is smart enough to solve the field theory of strings. Physicists use pertubation theory to add up small quantum corrections. Pertubation theory accounts for 99% of what physicists know about high energy physics. The problem is when they used it on string theory they got millions of possible solutions. Some that look a lot like our universe( corrisponds with the standard model, and some that don’t). It appears that a 10 dimensional universe has millions of different way it can curl up. To find which way that the ten dimensional universe perfers, they need to use non pertubative methods, and the math just hasn’t been found yet. No one is smart enough.

I guess back in 1993 this was cause for excitment, because string theory gave off definitions of the universe that looked a lot like ours, but once they realised that they didn’t have the means of solving the field theory of strings that excitment dwindled.

This actually brings about some disaterous consequences if string theory is correct. The frightening consequences of string theory is that the universe may not be in its true vaccum!!

K so at the big bang string theorists believe that the universe was a perfect 10 dimensions, but that it was unstable so the symmetry broke, and 4 dimensions rapidly expanded whilst the other 6 curled up.

So the universe was in a false vacuum, which was unstable, so the symmetry broke and formed what we hope to be the true vacuum(our four dimensional universe)

HEres a couple of examples.

Think of a bedsheet. Now you attempt to put a small bedsheet on a mattress that is too large, you succesfully get all the corners down, but its unstable because the sheet is too small, so one of the corners pops off and the bedsheet curls up. The bedsheet when succesfully covering the mattress is in a symmetrical state(its false vaccum), but its unstable so symmetry breaks, and forms its true vaccum(the sheet curled up), which is less symmetrical.

Or think of a dam. The flow of the water is held up creating more symmetry, a false vacuum, eventually the dam breaks into its true vacuum(the river running unempieded)

So for 10 dimensional universe it appears that there is millions of ways which it could curl up, one of those millions is the true vaccum. The disastrous consequences of string theory is that we may not be living in the true vacuum. So a bubble could appear in our universe, where in the bubble the standard model didn’t hold, and the laws of physics as we know them would be vastly different, a universe that would not support life. The bubble would expand at the speed of light, gobbling up our galaxy’s, and solar system’s, and we would never see it comming!!

Anyways just thought I’d throw that in there because it struck me a bit. As for the problems with string theorys, there are two major problems. Pertubation theory cannot solve the field theory of strings, and also string theory cannot be experimentally tested with the power available to us today.