what exactly is the M-theory in cosmology?
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Short answer it is meant to unify the supersting theories (which are of course aimed at answering the most fundamental question of the most elementary (sub)particles).\n\nLonger answer, there are dualities in the five "original" string theories. These dualities lead to the same pursuit as in the Grand Unification theory when people started thinking of more elegant theories. The M (or U) theory is basically the  grand unification of the five string theories. \n\nThe theory has a huge problem like the "originals", too many dimensions. Just as you can fit a polynomial of nth degree to any data, given enough dimensions you can explain any physical occurrence with almost any explanation this is why scientists are still dismissive of the M and String theories (except the guys who try to convince the rest)
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M-Theory\n\nThere are an infinite number of alternate realities which are integrating. Space-time distortions are occuring. For those who are clear, the observation and experience of these happenings is breathtaking. For others who are experiencing 'blindly' - to be 'out of phase' will cause confusion and fear.\n\nM-Theory unites the 5 superstring theories. According to M-Theory there are 11 spacial dimensions that exist in parallel with our physical reality. That goes along with the theory of 12 or 12 around 1 yet M-theory is not complete as all expands in reality and consciousness.\n\n      M-theory (sometimes also called U-theory) is a theory of physics, which is believed to incorporate and generalize the various superstring theories. Edward Witten proposed the existence of this physical model at a conference at USC in 1995, explaining a number of previously observed dualities and sparking a flurry of new research in string theory.\n\n      What does M stand for?\n\n      When Witten named M-theory, he did not specify what the "M" stood for, presumably because he did not feel he had the right to name a theory which he had not been able to fully describe. According to Witten himself, "'M' stands for 'Magic,' 'Mystery' or 'Membrane,' depending on your taste." Also suggested, has been 'Matrix' and 'Mother of all theories'. Cynics have noted that the M might be an upside down "W", standing for Witten. Others have suggested that for now, the "M" in M-theory should stand for Missing or Murky.\n\n      The name M-theory is slightly ambiguous. It can be used to refer to both the particular eleven-dimensional theory which Witten first proposed, or it can be used to refer to a kind of Uber theory which looks in various limits like the various string theories. Ashoke Sen has suggested that more general theory could go by the name U-theory, which might stand for Ur, or Uber, or Ultimate, or Underlying, or perhaps Unified. (It might also stand for U-duality, which is both a reference to Sen's own work and a kind of particle physics pun.) M-theory in the following descriptions refers to the more general theory, and will be specified when used in its more limited sense.\n\nIf you recall, I have written that the 'M' and the 'W' reverse at the end of time. Some see it as Man and Woman. They will rotate 180 [9] degrees - a 'U'. The 'M' and the 'W' can also be brought together - their ends meeting - then rotated 90 [9] degrees to form an hourglass. The possibilities are endless and will be studied until the end of time.\n\n      M-theory is not complete. It can be applied in many situations (usually by exploiting string theoretic dualities), but the full theory is not yet known. The theory of electromagnetism was also in such a state in the mid-19th century. There were separate theories for electricity and magnetism, and although they were known to be related, it was not clear until Maxwell published his equations just what the relationship was. Witten has suggested that a general formulation will probably require the development of new mathematical language.\n\n      It was shown in the early 1990s that the various superstring theories were related by dualities, which allowed physicists to relate the description of an object in one string theory to the description of a different object in another theory. These relationships imply that each of the string theories is a different aspect of a single underlying theory, which has been named "M-theory".\n\n      More from Wikipedia \n\nM-Theory was the underlying theme in the film, What the Bleep!\n\nM-Theory by George Minaya\n\nThe merging of dimensions integrates your consciousness and expands your awareness to the next level of understanding which will be followed by the merging of your soul aspects with other realities in which it experien
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oscillating universe\nIn astronomy, theory stating that the gravitational attraction of the mass within the universe will eventually slow down and stop the expansion of the universe. The outward motions of the galaxies will then be reversed, eventually resulting in a ‘Big Crunch’ where all the matter in the universe will be contracted into a small volume of high density. This could undergo a further Big Bang, thereby creating another expansion phase. The theory suggests that the universe would alternately expand and collapse through alternate Big Bangs and Big Crunches.
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Pierre Méchain\n\nIrregular galaxies are those which do not match the standard Hubble scheme of elliptical, spiral and lenticular galaxies. \nThere's only one irregular galaxy in Messier's catalog: M82, and this one is a distorted disk galaxy. The distortion is due to gravitational interaction with its larger and more massive neighbor M81. \n\nAnother, very similar example is at least mentioned in Messier's catalog, though it did not get a number on its own: NGC 5195, the companion of the Whirlpool galaxy M51, which had been discovered by Pierre Méchain. The only further irregular galaxies known to 1782 are the Large and the Small Magellanic Cloud; these are probably miniature disk galaxies in mutual gravitational interaction, and in interaction with our Milky Way.
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While I don't believe that there is an official explanation for M, the best I have heard so far is that M is for "modulus of slope".  A modulus is a number that represents to what extent a body has a certain property.  A modulus of slope would be how much slope the line has which is an accurate representation of "M" because it defines how steeply the line rises or falls.\n\nIf you are having a hard time remember that M controls the slope, just say that M represents the "Mope" (rhymes whit slope).  It sounds a little funny but that stuck in my head.
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The current status of the universe actually does work like that.  Technically, with gravity the universe should collapse back upon itself and the big bang would occur all over again.  However, gravity is one of the weakest forces in the universe.  With that said, it has been measured that the universe is expanding and accelerating at a rate that exceeds the gravitational forces required to initiate the "big crunch."\n\n\nThere are two schools of thought right now.  One is that the universe will continue to decelerate but never completely stop or collapse upon itself.  More recent theories have stated that the universe appears to be accelerating.\n\nAs it stands now, I would say that it is safe to say that the odds are extremely low of the universe collapsing back to a singularity.\n\nSee the link below for some more information.
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M Theory attempts to go beyond superstring theory and purport that the multiverse is made up of 11 dimensions. \n\nM Theory is based on mathematical calculations and not empirical data. However, M Theory does successfully account for every issue of all superstring theories (classical, quantum physics, etc) and mathematically postulates the number to be at 11. \n\nFor more information:\nhttp://en.wikipedia.org/wiki/M_theory
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Well, it is too complicted to explain in simple words, Here is a simplified version of the String theory-\nhttp://www.superstringtheory.com/basics/basic4.html\n\nI think you should read the Wikipedia articles about the String theory. Here they are-\nhttp://en.wikipedia.org/wiki/String_theory\nhttp://en.wikipedia.org/wiki/M-theory_(simplified)\n\nBut, if you want this topic to be explained thoroughly, see the "official website" on string theory-\n\nhttp://www.superstringtheory.com/basics/index.html
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You might be interested in M-theory of the universe. It suggests that the universe, ie the big bang that we see is the result of two higher dimensional membranes touching each other. Other membranes may actually touch and produce other kinds of universes but with physics that might be unstable or unusual
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Back in 1998 the idea of anti-gravity as a real phenomenon appeared to be possible - or is it?\n\nThe galaxies in the expanding universe appeared to be accelerating - was this some kind of anti-gravity force?  To account for this speed-up in expansion, most astronomers and astrophysicists favor bringing back Einstein's fudge factor. But keep in mind that no real evidence exists for reverse gravity; Einstein just made it up so that his equations would support the idea of a static universe. In a twist he could never have imagined, antigravity has returned to support the idea of a universe expanding forever at an increasing rate.\n\nThe fact that there MAY be an anti-gravity force implies there may be some way to take advantage of it, but if gravity is not actually a force but a distortion of space instead, the propulsion engine will have to find a way to distort space (we don't know how to do this).  When we understand the Higgs particle better, perhaps.\n\nCheck out the link below for an update on the subject of "anti-gravity"
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it basically says that there are these giant cosmic strings that stretch an infinite distance and they are very dense (as in they're so thin that they are not visible, yet a millimeter would weigh tons and tons) and their huge mass warps space-time and they help to make up the universe as we know it. there are also small vibrating strings on the sub atomic level that make up the smallest divisions of matter. String theory also describes 11 dimentions.  If you're interested in it, read "the elegant universe" by Brian Greene, it explains it a lot better than i can here.
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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!  ;-)
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The theory of dark matter has been developed to try and explain the observed characteristics of large-scale celestial objects, like galaxies. Mass (matter) causes gravity which in turn effects the shape and motions of things like spiral galaxies. However, the observed shape and motions of spiral galaxies can't be explained by the amount of matter known to be there. Some other kind of matter must be present, and that's called "dark matter."\n\nDon't confuse "dark matter" with "dark energy." The latter is another mysterious feature of the universe that is thought to be causing the expansion rate of the universe to be increasing.\n\nHere's the theorized percentages of dark matter, dark energy, and regular matter for the universe --\nDark matter.....23%\nDark energy.....73%\nRegular matter..4%\n\nYou could almost say that 97% of the universe appears to be missing :)
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its actualy String-theory that proposes the existance of many other universes. the theory proposes a so called "Landscape of probabilities" with probabilities of as many as 10 to power of 500 universes, and with that many probabilities it is very likely that some of them will be similar to or just like our own universe.\n\nif you would like to know more about this facsinating subject, i would suggest this book http://www.amazon.com/gp/product/0316155799/104-3626905-5554311?v=glance&n=283155\nits a great and easy to understand book.
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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.
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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.
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Before I start, I am a Biologist with an interest in theoretical physics, not actually a physicist, so my grasp of the finer detail may be shaky in places.  \nBasically string theory is an attempt to unify the elemental forces within the universe (Weak nuclear, Strong nuclear, Electromagnetic, and Gravity).  The theory postulates that various sub atomic particles are not particles but loops of vibrating energy so small that they have an almost “point” existence.  For string theory to work it is necessary to visual up to 26 separate dimensions (the 3 we know and love as well as other "compacted dimensions").  This may be the theory's downfall as it is next to impossiable to prove the existance of these extra dimensions and without them string theory just does not work!\nString theory has given rise to m-theory (which uses vibrating membranes (or 'branes if your a cool physicist) in place of strings), which may well prove to be a more accurate (if still incomplete) model for the way the universe works on both a sub atomic and an astrological level.