Persuade me about String Theory?
812818
Its beautiful, its elegant and it  holds promise. Its true that its some what stagnant in last few years but that doesn't mean we should start disbelieving it. If you cannot test something  experimentally that does not mean that it is incorrect.  You can refute something straight away only when you have proved it to be wrong.  While  thinking about a theory of everything, we must always keep a open mind. We should also for similar reasons give heed to other attempts towards a theory of everything.
510510
I would have to go with the Planck length on this one, which is a millionth of a billionth of a billionth of a billionth of a centimeter!  \n\nThe reason I say this: According to String Theory, strings are that long, and they are the fundamental building block of all matter.  Therefore, nothing exists that is smaller than that, so it is useless to have a smaller measurement.
621133
Oh my, have you opened up a can of nightmarish confusion.\n\nYou are referring to String Theory, and it is way too complicated to describe here.  Here is an exerpt from an article on wikipedia of String Theory that describes these extra dimensions:\n\nOne intriguing feature of string theory is that it predicts the number of dimensions which the universe should possess. Nothing in Maxwell's theory of electromagnetism or Einstein's theory of relativity makes this kind of prediction; these theories require physicists to insert the number of dimensions "by hand". The first person to add a fifth dimension to Einstein's four was the German mathematician Theodor Kaluza in 1919. The reason for the unobservability of the fifth dimension (its compactness) was suggested by the Swedish physicist Oskar Klein in 1926.\n\nInstead, string theory allows one to compute the number of spacetime dimensions from first principles. Technically, this happens because for a different number of dimensions, the theory has a gauge anomaly. This can be understood by noting that in a consistent theory which includes a photon (technically, a particle carring a force related to an unbroken gauge symmetry), it must be massless. The mass of the photon which is predicted by string theory depends on the energy of the string mode which represents the photon. This energy includes a contribution from Casimir effect, namely from quantum fluctuations in the string. The size of this contribution depends on the number of dimensions since for a larger number of dimensions, there are more possible fluctuations in the string position. Therefor, the photon will be massless - and the theory consistent - only for a particular number of dimensions.\n\nThe only problem is that when the calculation is done, the universe's dimensionality is not four as one may expect (three axes of space and one of time), but twenty-six. More precisely, bosonic string theories are 26-dimensional, while superstring and M-theories turn out to involve 10 or 11 dimensions. In bosonic string theories, the 26 dimensions come from the Polyakov equation (see technical details in the preprint "Quantum Geometry of Bosonic Strings - Revisited"). However, these results appear to contradict the observed four dimensional space-time.\n\n \nCalabi-Yau manifold (3D projection)Two different ways have been proposed to solve this apparent contradiction. The first is to compactify the extra dimensions; i.e., the 6 or 7 extra dimensions are so small as to be undetectable in our phenomenal experience. The 6-dimensional model's resolution is achieved with Calabi-Yau spaces. In 7 dimensions, they are termed G2 manifolds. Essentially these extra dimensions are compactified by causing them to loop back upon themselves.\n\nA standard analogy for this is to consider multidimensional space as a garden hose. If the hose is viewed from a sufficient distance, it appears to have only one dimension, its length. Indeed, think of a ball small enough to enter the hose but not too small. Throwing such a ball inside the hose, the ball would move more or less in one dimension; in any experiment we make by throwing such balls in the hose, the only important movement will be one-dimensional, that is, along the hose. However, as one approaches the hose, one discovers that it contains a second dimension, its circumference. Thus, a ant crawling inside it would move in two dimensions (and a fly flying in it would move in three dimensions). This "extra dimension" is only visible within a relatively close range to the hose, or if one "throws in" small enough objects. Similarly, the extra compact dimensions are only visible at extremely small distances, or by experimenting with particles with extremely small wave lengths (of the order of the compact dimension's radius), which in quantum mechanics means very high energies (see wave-particle duality).\n\nAnother possibility is that we
233899
Laney, first of all allow me to say that I'm incredibly glad and pleasantly surprised to hear of your genuine interest in this field.   You are to be truly commended for your intellectual courage and abilities.  ...But to address your question, there are in fact thousands of great explanatory/layman-type books out there on Quantum Mechanics, Field Theory, Gravity, Philosophy, Reality, and associated topics like cosmology, etc.  Some of them even dating back to the mid 70's, that nonetheless are still wonderful reads.  ...Theoretical physics at the level that we are talking about here, though, is unfortunately a seven-headed exotic mathematical monster that is not even accessible to most physicists, much less the lay person.   Having said that, and as you know, there have been courageous attempts by talented physicist like Brain Greene (and many others before and after him) to make our latest theoretical/scientific visions of the physical world/universe available to the general public.   ...Since you mentioned that you are NOT mathematically inclined, but did enjoy Greene's The Elegant Universe, the first thing that came to my mind (and the book that I would recommend most) was in fact Greene's newer work called "The Fabric of the Cosmos: Space, Time, and the Texture of Reality" - in case you haven't read it yet.    \n\nAmong some of the other more recent titles worth mentioning also are:\n\nThe Great Beyond - by: Paul Halpener (A very nice book)\n\nThe Cosmic Landscape - by: Leonard Susskind\n\nHiding in the Mirror - by: Lawrence M. Krauss\n\nThe Road to Reality - by: Rofer Penrose\n\nA First Course in String Theory - by: Barton Zwiebach (This is a very nice book but a lil' more mathematically oriented than you might enjoy - let's say undergraduate physics level) \n\nI also highly recommend:  The Five Ages of the Universe - by: Fred Adams\n\nThat should keep you busy for a while - Good Reading!  ;-)
18056
actually, physicists are still looking for the law of everything that connects the different theories of things and stuff.  String theory is pretty interesting although it doesnt provide definitive answers, it gets closer.  You seem interested in this stuff, you should read "The Elegent Universe" by Brian Greene.  It will explain a lot and help with your understanding.  Be warned though, you might find it too interesting and get too curious like me and end up being a physics major just to get some questions answered, and more do get answered the farther you go in physics haha. Read that book though, it will blow your mind.
238114
Dark matter is theoretical and therefore isn't explained by string theory...it is incorporated into the theory.\n\nDark matter "exists" only because the visible universe does not add up to be enough energy to have ignited the expansion of the universe.\n\nI personally feel string theory is a long shot.  Hyper inflation takes in a better account of what we observe.  And dark energy does exist in forms of massive blackholes (which are observable by outside observations: the gravitational impact the BHs make on celestrial bodies and light).
1038716
String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles) that are the basis of the Standard Model of particle physics. For this reason, string theories are able to avoid problems associated with the presence of pointlike particles in theories of physics. Studies of string theories have revealed that they predict not just strings, but also higher-dimensional objects.\n\nThe basic idea is that the fundamental constituents of reality are strings of energy of the Planck length (about 10-35 m) which vibrate at resonant specific frequencies[1]. Another key claim of the theory is that no measurable differences can be detected between strings that wrap around dimensions smaller than themselves and those that move along larger dimensions (i.e., physical processes in a dimension of size R match those in a dimension of size 1/R). Singularities are avoided because the observed consequences of "big crunches" never reach zero size. In fact, should the universe begin a "big crunch" sort of process, string theory dictates that the universe could never be smaller than the size of a string, at which point it would actually begin expanding.\n\nInterest in string theory is driven largely by the hope that it will prove to be a theory of everything. It is a possible solution of the quantum gravity problem, and in addition to gravity it can naturally describe interactions similar to electromagnetism and the other forces of nature. Superstring theories include fermions, the building blocks of matter, and incorporate supersymmetry. It is not yet known whether string theory will be able to describe a universe with the precise collection of forces and matter that is observed, nor how much freedom to choose those details that the theory will allow. String theory as a whole has not yet made falsifiable predictions that would allow it to be experimentally tested, though various special corners of the theory are accessible to planned observations and experiments. Hence critics of string theory occasionally remark that the theory "... is not even wrong," quoting a quip attributed to Wolfgang Pauli.\n\nWork on string theory has led to advances in mathematics, mainly in algebraic geometry. String theory has also led to other theories, supersymmetric gauge theories, which will be tested at the new Large Hadron Collider experiment.
115347
I would highly recommend the last answer. BRIAN GREENE's\nThe Elegant Universe. Great Book, I read it and it explains a lot in real English. Also check out his other book, which is also a great book on string theory its call "The fabric of the Cosmos"(great title!), a little more complex but highly usefull. Or if you hate to read, then buy the Nova special on string theory, which is hosted by Brian Greene (the author). He is one the lead string theorists. Mabye the next Einstein? (Possibly). I would watch the movie first. Then read the book, you would understand the material better with visuals.
1164474
String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles) that are the basis of the Standard Model of particle physics. For this reason, string theories are able to avoid problems associated with the presence of pointlike particles in a physical theory. Studies of string theories have revealed that they require not just strings, but also higher-dimensional objects.\n\nThe basic idea is that the fundamental constituents of reality are strings of energy of the Planck length (about 10-35 m) which vibrate at resonant specific frequencies[1]. Another key claim of the theory is that no measurable differences can be detected between strings that wrap around dimensions smaller than themselves and those that move along larger dimensions (i.e., physical processes in a dimension of size R match those in a dimension of size 1/R). Singularities are avoided because the observed consequences of "big crunches" never reach zero size. In fact, should the universe begin a "big crunch" sort of process, string theory dictates that the universe could never be smaller than the size of a string, at which point it would actually begin expanding.\n\nInterest in string theory is driven largely by the hope that it will prove to be a theory of everything. It is a possible solution of the quantum gravity problem, and in addition to gravity it can naturally describe interactions similar to electromagnetism and the other forces of nature. Superstring theories include fermions, the building blocks of matter, and incorporate supersymmetry. It is not yet known whether string theory will be able to describe a universe with the precise collection of forces and matter that is observed, nor how much freedom to choose those details that the theory will allow. String theory as a whole has not yet made falsifiable predictions that would allow it to be experimentally tested, though various special corners of the theory are accessible to planned observations and experiments. Hence critics of string theory occasionally remark that the theory "... is not even wrong," quoting a quip attributed to Wolfgang Pauli.\n\nWork on string theory has led to advances in mathematics, mainly in algebraic geometry. String theory has also led to other theories, supersymmetric gauge theories, which will be tested at the new Large Hadron Collider experiment.
191997
The very best explanation to this is a video I watched in my Philosophy class called "The String Theory" - it is amazing, and makes complete sense. If you looked it up on the internet, it goes into deep detail and is confusing. The video is by Nova (the science channel), and maybe someone else, but it is perfect. Unexplainably mind boggling and amazing.
665502
String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles) that are the basis of the Standard Model of particle physics. For this reason, string theories are able to avoid problems associated with the presence of pointlike particles in a physical theory. Studies of string theories have revealed that they require not just strings, but also higher-dimensional objects.\n\nThe basic idea is that the fundamental constituents of reality are strings of energy of the Planck length (about 10-35 m) which vibrate at resonant specific frequencies[1]. Another key claim of the theory is that no measurable differences can be detected between strings that wrap around dimensions smaller than themselves and those that move along larger dimensions (i.e., physical processes in a dimension of size R match those in a dimension of size 1/R). Singularities are avoided because the observed consequences of "big crunches" never reach zero size. In fact, should the universe begin a "big crunch" sort of process, string theory dictates that the universe could never be smaller than the size of a string, at which point it would actually begin expanding.
1131781
Superstring theory is an attempt to explain all of the particles and fundamental forces of nature in one theory by modeling them as vibrations of tiny supersymmetric strings. It is considered one of the most promising candidate theories of quantum gravity. Superstring theory is a shorthand for "supersymmetric string theory" because unlike bosonic string theory, it is the version of string theory that incorporates fermions and supersymmetry.\n\nThe deepest problem in theoretical physics is harmonizing the theory of general relativity, which describes gravitation and applies to large-scale structures (stars, galaxies, super clusters), with quantum mechanics which describes the other three fundamental forces acting on the microscopic scale.\n\nThe development of a quantum field theory of a force invariably results in infinite (and therefore useless) probabilities. Physicists have developed mathematical techniques (renormalization) to eliminate these infinities which work for the electromagnetic, strong nuclear and weak nuclear forces, but not gravity. Thus the development of a quantum theory of gravity must come about by different means than were used for the other forces.\n\nThe basic idea is that the fundamental constituents of reality are strings of the Planck length (about 10−35 m) which vibrate at resonant frequencies. The tension of a string (8.9×1042 newtons) is about 1041 times the tension of an average piano string (735 newtons). The graviton (the proposed messenger particle of the gravitational force), for example, is predicted by the theory to be a string with wave amplitude zero. Another key insight provided by the theory is that no measurable differences can be detected between strings that wrap around dimensions smaller than themselves and those that move along larger dimensions (i.e., effects in a dimension of size R equal those whose size is 1/R). Singularities are avoided because the observed consequences of "big crunches" never reach zero size. In fact, should the universe begin a "big crunch" sort of process, string theory dictates that the universe could never be smaller than the size of a string, at which point it would actually begin expanding.
317299
Ever since man took an interest in the sciences, from perhaps the time of Aristotle onwards, from time to time great ideas have been put forward. Some of these have seemed initially ludicrous, and turned out to be so. Others, with a little development, have given us a great insight into the way that the world works and enabled us to move on. \nAt a given moment of time, it may appear that what we know is fairly correct and will correct timelessly. However, history has shown that this is not the case. Eventually, perhaps, we will know everything, but right now this is far from the case. \nTake one of the fundamental aspects of physics, for instance. For a long time now people have thought that the matter is made up of tiny, invisible particles; atoms and their sub-components. This is the model we learn and that everyone worked around. \nYet in recent times, this has been challenged, by what is known as string theory - and it now seems that this is a better model, perhaps the more 'correct' one. \nString theory, against the traditional theory of matter, says that matter is caused by the vibrations of a string-like structure. These are the fundamental building blocks of matter. It is a bizarre sounding radical theory at first, but now has much support. \nJust like a violin string when plucked will produce sounds, and different sounds when plucked in different ways, so it is with the universe - with string theory, the fluctuations give rise to matter. On this view, the universe may romantically be described as a symphony. The framework of the vibrating string causes the song that we see around us. \nThis, then, in outline is string theory, and it has greatly changed the way that modern physicists do their subject.
91646
String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles) that are the basis of the Standard Model of particle physics. For this reason, string theories are able to avoid problems associated with the presence of pointlike particles in a physical theory. Studies of string theories have revealed that they require not just strings but also higher-dimensional objects.\n\nThe basic idea is that the fundamental constituents of reality are strings of energy of the Planck length (about 10-35 m) which vibrate at resonant specific frequencies[1]. Another key claim of the theory is that no measurable differences can be detected between strings that wrap around dimensions smaller than themselves and those that move along larger dimensions (i.e., effects in a dimension of size R equal those whose size is 1/R). Singularities are avoided because the observed consequences of "big crunches" never reach zero size. In fact, should the universe begin a "big crunch" sort of process, string theory dictates that the universe could never be smaller than the size of a string, at which point it would actually begin expanding.\n\nInterest in string theory is driven largely by the hope that it will prove to be a theory of everything. It is a possible solution of the quantum gravity problem, and in addition to gravity it can naturally describe interactions similar to electromagnetism and the other forces of nature. Superstring theories include fermions, the building blocks of matter, and incorporate supersymmetry. It is not yet known whether string theory is able to describe a universe with the precise collection of forces and matter that is observed, nor how much freedom to choose those details the theory will allow. String theory as a whole has not yet made falsifiable predictions that would allow it to be experimentally tested, though various special corners of the theory are accessible to planned observations and experiments.\n\nWork on string theory has led to advances in mathematics, mainly in algebraic geometry. String theory has also led to other theories, supersymmetric gauge theories, which will be tested at the new Large Hadron Collider experiment.
902557
If superstring theory is correct and really needs 10 or more dimensions, then it would'nt surprise me if at least one more in the pile was temporal.  If I had to bet, I'd bet against it.
246328
String theory is still quite new in the world of physics, but it has drawn tremendous attention to all physicists around the world. \nFor the last 80 years or so physicists have been trying to find a theory that will combine the theories of quantum mechanics and general relativity. These two theories describe everything in the universe. General relativity does this on the scale of the very large e.g. planets, galaxies and so on. When it comes to subatomic scale, like protons, quarks etc. general relativity breaks down. This is where quantum mechanics is very accurate, but quantum mechanics does not work when applied to the very large objects. \nGeneral relativity basically deals with gravity and has a calm feeling to it. The predictions it makes is always sort of neat and precise.\nQuantum mechanics on the other hand deals with the uncertainty principal and has a very chaotic feel to it.\n\n\nString theory is what physicisits hope and believe might be the theory combines these two super theories. String theory predicts that every particle (even quarks) are made up of much, much smaller particles called strings. They are not really particles, they are actually vibrating strands of energy. Each of these strands vibrate in a different way. \n\nThe mathematics behind string theory works so well that many believe string theory has to be true, but unfortunately there is currently no way to prove string theory with experiment. If string theory is true, then some of our notions of the universe will have to change dramatically. We will have to accept that we actually live in an 11-dimensional universe.
891719
In all honesty you can't. String theory is so mathematically complex that you basically need a PhD in string theory to understand it, in fact most PhD physicists who are not string theorists don't understand it, nor do the want to (and a lot of them are opposed to it).\n\nString theory is a very dangerous endeavor. Some of the stuff it suggests (like time travel) are fun to think about, but it has yet yielded an experiment that could be used to test its validity. There has never been anything observed, no measurement taken, that could prove sting theory true or false. So far, it is only a set of very complicated mathematical expressions that may or may not describe the world we live in. \n\nI think its great that your cousin has taken an interest in physics. But I think it would be best if you steer him away from books on string theory. There are many fascinating physical phenomena that have been observed that have nothing to do with strings. I would suggest that he read "1 2 3 ... infinity" by Gamow.