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membrane_theory [2008-05-27 17:03] – 62.202.92.250membrane_theory [2011-02-14 17:04] – FdiywlvrLMtZXEnRU 174.132.220.135
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- +lFsgau  <a href="http://ybtliuyixyxi.com/">ybtliuyixyxi</a>, [url=http://nfrydgmgutxz.com/]nfrydgmgutxz[/url], [link=http://bnlnyxebwtwg.com/]bnlnyxebwtwg[/link], http://mygwnjadawis.com/
- +
-==== Subject: we have a theory of everything now - we can all relax ==== +
- +
- +
- +
-by Honor Harger (with small edits and transclusions by [[nik gaffney]]) +
- +
- +
-basically, it appears that thanks to the popularisation of the eleventh dimension, a rock climbing physicist's fascination with parallel universes, and some crazy talk by three physicists stuck in a train on their way to london, we now understand everything wow... +
-==== The [Latest] Theory of Everything. ==== +
- +
-Yep, its sorted now.  We apparently understand more or less everything +
-about where the universe began, what started it, and what's in it.  It +
-turns out we live in a lumpy multiversal sea where bubble-like +
-universes are thrown into each other like tidal waves. +
- +
-Here is the deal ..... +
- +
- +
-In the effort to establish a unified theory of everything, a theory of +
-matter was developed in the 1980s and 90s called String Theory. +
- +
- +
-For years it had been an article of faith that all the matter in the +
-Universe was made of tiny, invisible particles. In the 1980s the +
-particle physicists discovered they'd been studying the wrong thing. +
-The particles were really tiny, invisible strings. The theory was +
-called String Theory and it maintained that matter emanated from these +
-tiny strings like music. +
- +
- +
-As physicist, Burt Ovrut comments: "you can think of it as a violin +
-string or a guitar string. If you pluck it in a certain way you get a +
-certain frequency, but if you pluck it a different way you can get more +
-frequencies on this string and in fact you have different notes. Nature +
-is made of all the little notes, the musical notes, that are played on +
-these super-strings." +
- +
- +
-Another physicist, Michio Kaku reiterates, "All of a sudden we realised +
-the Universe is a symphony and the laws of physics are harmonies of a +
-super-string" +
- +
- +
-String Theory proved provocative.  It was widely considered to be the +
-closest theory to explaining everything which existed in the Universe. +
-It seemed to neatly summarise the material aspects of the universe. +
- +
- +
-String Theory utilised additional dimensions in its framework.  The +
-extra dimensions were spaces in the Universe which we could not +
-perceive.  String Theory was characterised by considering the universe +
-as a ten dimensional, but other theories used different numbers of +
-dimensions. For instance, super gravity, argued by Michael Duff of the +
-University of Michigan, was a comparatively obscure theory which had +
-long existed in the shadow of String Theory, as a single unifying +
-universal theory.  Super gravitists posited that the Universe was +
-composed of 11 dimensions.  The Eleventh Dimension had always been +
-ridiculed by String Theorists. +
- +
- +
-If String Theory was to become Einstein's missing Theory of Everything +
-it would have to pass one test. It would have to explain the birth of +
-the Universe.  The origins of the Universe had always been the subject +
-of the cosmologists who believed things had started with a giant +
-explosion - the Big Bang.  While initially String Theory and the Big +
-Bang seemed to work perfectly in tandem as dual explanations for the +
-Universe (one explained its origins, the other everything which existed +
-in the Universe), problems soon started to emerge. +
- +
- +
-In the early 1990s a major problem with String Theory developed.  As +
-more people worked in it, competing theories began to be developed, +
-variants on the original premises of the theory.  In the end, five +
-separate theories existed, each a subtle variant on the original String +
-Theory.  For a theory proposing to address the universe's questions, +
-this was a major problem.  String Theory's credibility rested on its +
-claim to be a single answer to the universe's mysteries. +
- +
- +
-At the same moment, String Theory began to break down, cosmologists +
-began to have major problems with the Big Bang as a theory of +
-explaining the origin of the universe.  As Alan Guth, a cosmologist +
-explains: "In spite of the fact that we call it the Big Bang Theory it +
-really says absolutely nothing about the Big Bang. It doesn't tell us +
-what banged, why it banged, what caused it to bang. It doesn't even +
-describe, doesn't really allow us to predict what the conditions are +
-immediately after this bang." +
- +
- +
-In the early 1990s, with String Theory in tatters, a group of +
-physicists tried one last variant in their calculations.  In a final +
-desperate move the string theorists tried adding the very thing they +
-had spent a decade rubbishing: the eleventh dimension. Something almost +
-magical happened.  When the calculations were re-done, with the +
-addition of the new dimension, all five variants on String Theory +
-turned out to be the same theory.  The five String Theories turned out +
-to be simply different manifestations of a more fundamental theory. +
-The additional dimension, had not only solved String Theory's problems, +
-but also had rehabilitated the work of the super gravitists who had +
-long been operating in the Eleventh Dimension. +
- +
- +
-It looked as if a single unifying theory explaining the universe was, +
-after all, plausible. +
- +
- +
-The new dimension - the Eleventh - was a strange place.  It was +
-calculated to be infinitely long, yet extremely narrow in width - an +
-estimated trillionth of a millimetre wide (and thus imperceptible). The +
-laws of physics as we know them would likely not operate in this +
-dimension. +
- +
- +
-When scientist began to experiment using the Eleventh Dimension, +
-something very odd began to happen.  When physicists began to recreate +
-their experiments using the additional dimension, they began to +
-discover that the 'strings' of previous theoretical assumptions, were +
-turning out to be distinctly 'unstringy'.  The stuff which all matter +
-was composed, in this new theory seemed much more lumpy, more elastic +
-than a string.  Now, with the addition of the eleventh dimension, the +
-tiny invisible strings were changing. They stretched and they combined. +
-The astonishing conclusion was that all the matter in the Universe was +
-connected to one vast structure: a membrane. In effect, our entire +
-Universe is a membrane. The quest to explain everything in the Universe +
-could begin again and at its heart would be this new theory. Membrane +
-Theory, or M-Theory for short. +
- +
- +
-( +
-While all of this took place a rock-climbing physicist from Harvard +
-University - Lisa Randall - had been greatly troubled by one of our +
-physical forces: gravity.  Why was it that gravitational force was so +
-comparatively weak, when compared with other physical forces? Though +
-intuitively gravity seems rather strong - it fixes us to the planet, +
-for instance - it is in fact surprisingly weak.  Despite the force of +
-the sum of the Earth's gravitation pull on us, we are still able to +
-move, for instance.  Gravity's force can be overcome extremely simply, +
-by using a weak magnet.  A metallic object such as a pin can be lifted +
-out of gravity's pull very simply using such a magnet.  Why is this? +
-Could it be that its force is being dissipated in some way?  Could +
-gravity be somehow 'leaking' into, for instance, the Eleventh +
-Dimension?  When Lisa Randall carried out experiments to check the +
-validity of this hypothesis, her calculations wouldn't compute.  Then, +
-she started to consider a bizarre proposition.  Instead of gravity +
-leaking from our universe into one of our more unusual dimensions, +
-could gravity be instead **originate** from a different membrane, +
-elsewhere, and be leaking into our universe?  In effect, could gravity +
-come from a parallel universe?  When Lisa Randall redid her +
-calculations using an alternative membrane as a point of origin for +
-gravity, she resolved her equations. The weakness of gravity could at +
-last be explained, but only by introducing the idea of a parallel +
-universe +
- +
- +
-The concept of a parallel universe seemed to be hypothetically +
-plausible, under M-Theory.  Now suddenly physicists all over the world +
-piled into the eleventh dimension trying to solve age-old problems and +
-every time it seemed the perfect explanation was another parallel +
-universe. Everywhere they looked it seemed they began to find more and +
-more of them. From every corner of the eleventh dimension parallel +
-universes came crawling out of the woodwork. Some took the form of +
-three-dimensional membranes, like our own Universe. Others were merely +
-sheets of energy. Then there were cylindrical and even looped +
-membranes. Within no time at all the eleventh dimension seemed to be +
-jam-packed full of membranes.  Physicist Burt Ovrut also proposed that +
-occasionally membranes would collide.  Universes in the Eleventh +
-dimension would behave in much the same way as massive turbulent waves, +
-occasionally banging into each other, creating vast disturbances. +
- +
- +
-M Theory was getting stranger and stranger, but could it really be a +
-theory which explained everything in our Universe? To have any chance +
-of that it would have to do something no other rival theory had ever +
-been able to do. It would have to make sense of the baffling +
-singularity at the beginning of the Big Bang. +
- +
- +
-In 2002, Neil Turok, Paul Steinhardt and Burt Ovrut had a crazy +
-conversation in a train on the way to London.  They wondered if the Big +
-Bang might be the aftermath of some encounter between two parallel +
-worlds.  Membranes which behaved as waves do, membranes which ripple, +
-would, in a collision create clumps of energy, some of which could form +
-into matter. +
- +
- +
-The singularity had disappeared and it had taken them just under an +
-hour.  If it computed it later experiments, M Theory may really be +
-able to explain everything in the Universe. +
- +
- +
-Later experiments and calculations seem to have borne out the train +
-chat.  It seems indeed that our universe could be just one bubble +
-floating in an ocean of other bubbles. +
- +
- +
-**References:**  +
- +
- +
-  * M-theory, the theory formerly known as Strings: The Standard Model Cambridge http://www.damtp.cam.ac.uk/user/gr/public/qg_ss.html +
-  * Burt Ovrut Dept Physics, University of Pennsylvania http://dept.physics.upenn.edu/facultyinfo/ovrut1.htm +
-  * The Endless Universe: A Brief Introduction to the Cyclic Universe by Paul J. Steinhardt +
-  * Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544, USA http://feynman.princeton.edu/~steinh/cyclintro/ +
-  * Brane-Storm' Challenges Part of Big Bang Theory By Robert Roy Britt http://www.space.com/scienceastronomy/astronomy/bigbang_alternative_010413-1.html +
-  * Connecting Fundamental Physics and Cosmology http://www.newton.cam.ac.uk/programs/SFU/sfuw03.html +
-  * Big Bang's New Rival Debuts With a Splash by Charles Seife http://www.phy.pku.edu.cn/~xuegong/ccp1/html/news/sciencenews/sn%204.14%20New%20Rival%20Debuts.htm +
-  * transcript of BBC interview with Ovrut, Turok and co. http://www.bbc.co.uk/science/horizon/2001/parallelunitrans.shtml +
- +
- +
-more (or less related) notes +
-  * http://xxx.soton.ac.uk/abs/hep-th/0209158 +
- +
- +
-[[Category Physics]]+
  • membrane_theory.txt
  • Last modified: 2011-10-27 19:46
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