October 5th, 2006, 09:29 PM
Why don't they work togeather? is there some science behind "if there is a big enough explosion the strings will snap" or somthing like that? I just don't see why they can't. Is it because the Big Bang is the start of the universe but String theory shows that there is no start?
as ive understand it they dont go against each other. its rather so that string theory explains big bang
October 6th, 2006, 05:12 AM
Where in the world did you get the impression that the Big Bang and String theory don't go togehter??????Originally Posted by Ian12
The fundamental problem in physics in the last few decades has been that we have been using quantum field theory to describe all the forces of nature except gravity which has been described by the "classical" theory known as General Relativity. Attempts to quantize General Relativity (that is turn GR into a quantum field theory) failed. Thus the holy grail of modern physics has been the Unified field theory which includes the force of gravity as a quantized field along with Elecromagnetism, strong and weak nuclear forces in one theory of everything. The idea that has shown the most promise in achieving this is String Theory and in its latest and most developed form today (called M theory) it can be interpreted as a version of General Relativity reformulated in eleven dimensions.
For String Theory to work it must be shown to be equivalent at low energies to the separate theories of General Relativity and the Standard Model (which is the current quantum field theory of the other three forces). That would include an agreement with the Big Bang theory. However, despite the steady advances in string theory, this is not a complete or verified theory as of yet. There is still a lot of work to be done before string theory will be accepted by the physics community as a realization of the goal of a Unified Field Theory.
If all these theories are tied together such that a unified theory of everything is found, can anybody see what benefit this might have? what practical benefits might be gained?
I really would like to know, is it just curiosity?
the knowledge of having the knowledge is reward enoughIf all these theories are tied together such that a unified theory of everything is found, can anybody see what benefit this might have? what practical benefits might be gained?
How about being capable of modeling any physical event. That knowledge could be used to solve the worlds problems like tornados, AIDS, how to create anti-gravity etc.. The thing about these theories is they are mathematical equations and really good ones at that. They aren't just a painting of pretty words that make people happy. The only problem with the above is even when we get the equations working finally, the computers we have right now are so frickin slow. It would take all the worlds computational power to model 1 gram of water with these equations in a real time scenario. But hey it may be usefull to me when I finish video game developement school.
String Theory helps the BB in several ways. It removes the infinitely dense singularity you get with QM as the origin of the universe would be a 2D string and not a point.
String theory also has membranes which strings are attached to and which make up seperate universes. It's theorized that if two of these membranes came into contact you would get a release of energy identical to BB.
are these membranes in anyway related to the submanifolds and extra dimensions or are you refering to something else
No, these would be larger structures that open strings are attached to and what we experience as the universe. From what I understand of string theory, gravitons could be closed strings that are not attached to a membrane and are able to move between seperate universes(if they exist) helping to explain why gravity seems to be such a weak force. We only see a small portion of the total gravtational force because it's spread out over multiple universes.
Stylin! What's the recomended reading on string theory!
one of the biggest problems with string theory is it presumably occurs at the sub-planck level and therefore can not be measured. So at this point no matter how extensive the math or how much agreement with observation we see there is no independant verification. String theory may in time turn out to be the next great step or just a four decade long waste of time. As for conflict with BB there really isn't one because string theory is being optimized to agree with current cosmology and confirm present data.
While string theory is more philosophy than science right now there's indirect evidence that's being looked for like supersymmetry and the lose of mass in high energy collisions that would indicate movement of gravitons between membranes.
String theory is appealing because it fills in holes left by Quantum Mechanics and General Relativity. Whether or not it's accurate only time will tell.
A good book on string theory is Brian Greenes' "The Elegant Universe".
btw, most strings would be at the Planck length of 10^-33 cm, although it's possible there are much larger strings in existance. They would have been formed in the high energy environment of the very early universe and could possibly be detectable.
The whole of string theory is founded on a very specific equation, not phillosophy. Although as put above, not yet observeable. It does however support most present day theories and helps to unify them(Special/General Relativity, Quantum Model, Big Bang). I quickly read some parts of a book on the subject(mathematically founded) and do understand most of whats being said. I should take a look at "The Elegant Universe" again, but I think I picked it up one time and thought "hmmmmm another stupid phillosophy book" then put it down. In fact I think we have it in the library I'm presently in.............
The cosmic strings are a different beast in species to the strings in string theory DarcgreY - the former come from topological breakdowns in GR and the latter are an entirely new theory.
I read a few pages of the book online on Amazon and read some reviews. The reviews mention that if you are already well versed in physics and the mathmatics and string theory, then there's not much there for you. It is written for people who don't know physics, but do have some kind of technical background - so can keep up with technical ideas and so forth.
There is as little math as possible, but there are a couple of chapters on it that have been dubbed the "dull chapters" because they are math heavy.
I'm going to buy the book as soon as possible. The few pages I read, sounds like it's what I've been looking for.
What book where you reading Beky?
The problem with a string theory is exactly that - you are spoiled for choice and until someone can actually work out if the mythical M-theory actually exists string theory is going to just be a mathematicians pllay ground. There is a reason Witten got a fields medal and not a nobel
Yah, The Elegant Universe is for those of us who are mathematically challenged. I tend to like big ideas but actually working out the nuts and bolts literally puts me to sleep.
When I say it's more philosophy, I mean that there's no experimental tests that can directly confirm it at this time. There are very intricate mathematical models, that while they do give interesting results can not be applied to the material world(unless things have changed radically in the last year or so).
IIRC strings large enough to be detected are possible under the theory, and they're different from cosmic strings. The amount of energy that goes into the creation of a string determines its' size. In the high energy environment of the early universe it's possible that some large strings were formed. Finding them would be exceedingly difficult tho...The cosmic strings are a different beast in species to the strings in string theory DarcgreY - the former come from topological breakdowns in GR and the latter are an entirely new theory.
Never heard of Type IIRC strings (Just type A and B) but then again i am not a string theorist. I know that if you pump enough energy into a string it should become macroscopic - but what scale are these IIRC strings?
According to The Elegant Universe, a string was a billion billion times smaller than the nucleus of an atom. How small can we see nowadays? Can we really detect something that freaking small?
I'm just going by what I've read, I don't understand the math so I could be wrong. From my limited understanding, strings large enough to detect are possible but it's an extremely long shot to find them. Considering they would have been formed at the start of the universe they would be very distant objects. They would appear as a discontinuity or a ripple in space in front of other objects and wouldn't give off light.
Well, I guess I'll learn more about this when I read that book. I got the impression that strings were everywhere. It's obvious I don't understand this concept at all - haha!
If Superstring Theory is correct, strings are everywhere, as all matter is composed of them at a most basic level. They would be the point where energy becomes matter as we concieve it. Strings are vibrational energy bound up in such a fashion(this is where the multidimensions come in) to give matter it's characteristics.Well, I guess I'll learn more about this when I read that book. I got the impression that strings were everywhere. It's obvious I don't understand this concept at all - haha!
Large strings would be a rare anomaly produced by conditions that haven't been present for over 13 billion years.
mmm sounds similar to those missing magnetic monopoles! Damn inflation
That's the joy of science, if your theory isn't supported by observation make it more complicated.mmm sounds similar to those missing magnetic monopoles! Damn inflation
Again, the thing is it's about math. I have seen some of the more intensive math involved in string theory and regularily see it when I'm trying to model atoms(still trying). String theory doesn't have to be observed it's an extrapolation of information. As long as we get something that works to our advantage it really doesn't matter if it's wrong(kind of sort of). The only thing I really don't like about string theory is the term extra dimensions used to describe the submanifolds. They still operate in 3d space as a 2D entity. The fact that they only have an effect on space limited to their 2D orbital infliction on the rest of space(like digital they are or they are not) doesn't mean they are on some foreign tangent. Although in a matrix term they could essentially create a condition where multiple platforms could exist within the same space without being observed by the other; this is the purely theoretical portion of the thesis(anybody ever seen the people that are comprised of air currents). I hope to one day model atoms and know that it can be done without strings. Still strings would add that degree of certainty that would help us to develope transporter technology. I should probably read The Elegant Universe but I get pretty boared when I read anything, that's why I like math. You can sum up an entire book in 7 - 8, pretty, litle, equations! Ah well........
Nova did an interesting series on The Elegant Universe, here's the link to the website:
http://www.pbs.org/wgbh/nova/elegant/
Stylin Yo! The part on imagining other dimensions actually described everything I've been sayin wich makes me feel better
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