String Theory

Is anybody in here familiar with string thoery? I'm currently reading a book called The Elegant Universe, and the theory is just mind blowing, I'm having a hard time wrapping my brain around the concept of additional dimensions. I was wondering if there was anybody who could share what they know?

 

Basically the theory states that there are not four, but ten (or 26, according to some physicists) dimensions to our universe. The other six are just so astronomically small that we can't detect them and probably will never be able to detect them. Imagine a flat piece of paper as a universe. To a person in that universe, there are only two dimensions...he can't even detect the thickness of the paper because it's so small.

It's a very promising and interesting theory, but as of yet, there's no concrete evidence that it is correct. Strings have never been detected. The main thing the theory has going for it is the mathematical elegance of it. String theory is able to unite gravity with the electromagnetic, strong, and weak forces...which the Standard Model has never been able to do.

If it proves to be true, it would represent a major milestone in physics.

 

There are 26 dimensions that split into 16 and 10 right after the big bang and I have no idea where the other 16 went. Mind you I dont really get where 6 of the 10 are. The result of this (apparently) is that every fundamental particles can be considered a vibrating string and different modes of string relate to different particles. The miinor flaw of string theory is not just that there is no experimental evidence, but its equations are very complex. As of yet a way to solve these equations is yet to be found. This is where my objection begin.
I'm not a big fan of string theory. For centuries science has gone on the same principle of hypothesis -> experiment -> conclusion -> hypothesis and so on. String theory breaks this in that it is entirely mathematical as has been pointed out there is no chance of it being proven any time soon (certainly not within the next thousnad years if our ability to generate energy keeps going at the same rate it has the last century). The standard model has very successfully united electromagnetism to the weak force and unification with the strong force is near. Experiment and theory of the standard model agree to the same degree as measuring the distance from London to Los Angeles to the width of a human hair, that is impressive science. Leaving only gravity. This has been done with the backup of experiment, as well as a rigorous mathematical background. Without experiement, to my mind, the gap between religion and science becomes blurred. To me its not maths that makes good science, but the demonstraion of theory by replicable experiment.

 

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Man just from the 3 replies I've gotten...I clearly need to do more reading on said subject.

/Shoulda taken physics in high-school

 

The current minimum half life of a proton based on the results of the heavy water experiments is 3x10^33 years. This is inconsistent with any of the GUT (Grand Unified Theories) so far postulated. Bearing in mind that a GUT doesnt incorporate gravity only the other 3 forces. I think that we're close to unifying 3 of the 4 but I suspect gravity is someway off a demonstrable working theory and a very long way off experimental proof.

 

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Nope not yet, and all the candidate GUT's say we should have. With each day that passes the half life gets bigger, assuming the proton isn't perfectly stable. Which would suprise me, I think im right in saying it would be the only hadron (thing made of quarks) to be perfectly stable.

 

I'm not with that there's greater out there. The truth is we're depleting here. This planet is shrinking, and, normally, at the planet's surface, everything is perfect and there is space for everything.

Exp? the surface is so very vast, that one person's mind doesn't encompass an upward or a skyward,but lives in balance with the natural surrounding.

Cause? Oil drilling.

Since it is getting smaller, the amount of space (head space) is less, and so, being that we are not trees, the problem is more than that of overcrowding, get me? The dimensional reality is getting crowded.

So much as we like to think there is better "out there", the problem lies here, and, since I'm a firm believer in cause and effect, maybe there's a promising future out there that we all yearn for.

Let's work now to make it happen!

 

My theory about gravity is that it is a result of our solar system providing life to the only planet in it that is capable of sustaining life, and that it is that life, that continues it on the onward spiral that moves it into it's own little gyro of life sustainment and life. It's reciprocal. Astrology is a great thing to believe in. It gives each of the planets personality in a person's chart, and, it's fun. I like to think that planetary vibrations, along with planet earth, make life happen here, that they are not large mundane rocks, but have a living entity of their own, and that is each, their own, to work together to continue life on earth. I'm not saying they're alive, I'm saying they are a natural force to sustain life here on earth, AND, I also think we work the same way interchangeably, with ET.

Gravity is provable, then, by vacuums and G forces, like a fast moving model of a solar system featuring vacuum enough to produce the desired result.

So far as weighing/measuring the half life of a proton, I think it's unreliable to use a mathmatical source that doesn't incorporate gravity, since it is so essential to anything and everything on the planet earth, to make a mathmatical figure that leaves it out, isn't that fiction?

Earth spins.

 

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I agree. Hopefully CERN will be able to detect proton decay when it opens next year.

 

Dunno if CERN will detect proton decay, they tend to blow them apart before they have a chance to decay. But there are many giant tanks of water on the case. Also it would be nice to find a hole in the standard model. It can't explain everything and if it can't be found to be wrong then we are left with a correct theory that doesnt fit everything we see, clearly this would be a minor issue for physics.

Protons and electrons aren't all that similar. Electrons are a fundamental particle protons most definately are not. They are completely different classes of particle, a proton is a hadron and an electron is a lepton. Really all they have in common is that the anti-particle of one happens to equal the charge of the other. Given that the universe, more than likely, a started from a single point it should not hterefore be suprising that the entire known universe stems from those boundary conditions.

 

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i don't think i can add anything, but i am a fan of string theory...


and it's not purely mathematical...actuallly

 

There is very little in common between leptons and hadrons. They can interact by the weak and EM (assuming they carry a charge). Hadrons can also interact via the strong interaction. All 3 of the above forces require charge to be conserved as a condition of the intereaction. These charges should therefore be defined in the early second of the universe when the conservation laws became defined at the moment of the separation of forces. The fact that e does not change with time is an assumption of the standard model, not a result as far as I know. The same assumption has been made about the speed of light, an assumption that could still be wrong. Put simply going by current theory the fundamental constants were defined before/as the forces separated and they are time independant (if either of the above is wrong then current theorys are a little useless).

As for superstring theory not being entirely mathematical, pray tell. Im a very large sceptic. Its a nice idea but from a scientific persfective its like a guess with a lot of maths in it.

 

my guess is that the number of dimentions is not relevant. what is you might ask ? well, to try to make the most of our own 3 dimention universe. Numbering is like in a matematic equation. Is not pre-defined. Hope to understand my poor English.

 

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Leptons are more fundamental then protons, all baryons and mesons (hadrons together) are made of quarks which right now are thought to be fundamental. The leptons have no subdivisible components and are in themselves fundamental.

A particle made of 6 protons could exist, so a particle of -2e this is not banned by QCD, however I believe such a thing would be very unstable. There is of course no version of the strong force applying for leptons so 2 electrons could only intereact via the EM interaction this of course prevents 2 electrons holding together.

The vast majority of particle out there are the various combinations of quarks allowed by QCD. Apart from that there are only 6 leptons and the particles to carry the forces. In a way you are left with a chicken and egg situation. The particles that exist seem to exist because they are all possible intereactions of the forces. The fact that the universe is isotropic is given as evidece of the big bang so we'd expect common particles wherever we looked in the unvierse, this should not come as a suprise. The various laws came into existance as the forces separated from each other and before this the particles were independant from each other anyway. So in the GUT and TOE eras leptons and hadrons were the same thing anyway. However there are some constants that we may never know why they were chosen, they are defining constants of the universe, it maybe that an explanation of e will be found. Asfor the conservation laws they seem to exist because the universe seems to be built on gauge theories of which conservation laws are a big part. Then you have the question why do gauge theories explain the universe im sure someone will answer that with another question as well.

 

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