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Showing posts with label Paul Steinhardt. Show all posts
Showing posts with label Paul Steinhardt. Show all posts

Sunday, June 02, 2013

Two Paul Steinhardt Projects: "Cyclic Universe" and "Quasicrystals"



Two Paul Steinhardt Projects: "Cyclic Universe" and "Quasicrystals"






Albert Einstein Professor in Science, Departments of Physics and Astrophysical...
Quasi-elegance....As a young student first reading Weyl's book, crystallography seemed like the "ideal" of what one should be aiming for in science: elegant mathematics that provides a complete understanding of all physical possibilities. Ironically, many years later, I played a role in showing that my "ideal" was seriously flawed. In 1984, Dan Shechtman, Ilan Blech, Denis Gratias and John Cahn reported the discovery of a puzzling manmade alloy of aluminumand manganese with icosahedral symmetry. Icosahedral symmetry, with its six five-fold symmetry axes, is the most famous forbidden crystal symmetry. As luck would have it, Dov Levine (Technion) and I had been developing a hypothetical idea of a new form of solid that we dubbed quasicrystals, short for quasiperiodic crystals. (A quasiperiodic atomic arrangement means the atomic positions can be described by a sum of oscillatory functions whose frequencies have an irrational ratio.) We were inspired by a two-dimensional tiling invented by Sir Roger Penrose known as the Penrose tiling, comprised of two tiles arranged in a five-fold symmetric pattern. We showed that quasicrystals could exist in three dimensions and were not subject to the rules of crystallography. In fact, they could have any of the symmetries forbidden to crystals. Furthermore, we showed that the diffraction patterns predicted for icosahedral quasicrystals matched the Shechtman et al. observations. Since 1984, quasicrystals with other forbidden symmetries have been synthesized in the laboratory. The 2011 Nobel Prize in Chemistry was awarded to Dan Shechtman for his experimental breakthrough that changed our thinking about possible forms of matter. More recently, colleagues and I have found evidence that quasicrystals may have been among the first minerals to have formed in the solar system.

The crystallography I first encountered in Weyl's book, thought to be complete and immutable, turned out to be woefully incomplete, missing literally an uncountable number of possible symmetries for matter. Perhaps there is a lesson to be learned: While elegance and simplicity are often useful criteria for judging theories, they can sometimes mislead us into thinking we are right, when we are actually infinitely wrong. See:

2012 : WHAT IS YOUR FAVORITE DEEP, ELEGANT, OR BEAUTIFUL EXPLANATION?



See Also:

Sunday, January 15, 2012

WHAT IS YOUR FAVORITE DEEP, ELEGANT, OR BEAUTIFUL EXPLANATION?

Scientists' greatest pleasure comes from theories that derive the solution to some deep puzzle from a small set of simple principles in a surprising way. These explanations are called "beautiful" or "elegant". Historical examples are Kepler's explanation of complex planetary motions as simple ellipses, Bohr's explanation of the periodic table of the elements in terms of electron shells, and Watson and Crick's double helix. Einstein famously said that he did not need experimental confirmation of his general theory of relativity because it "was so beautiful it had to be true." See:2012 : WHAT IS YOUR FAVORITE DEEP, ELEGANT, OR BEAUTIFUL EXPLANATION?
See which comments resonate with you. Some of my picks as I go through was by :

Raphael Bousso
Professor of Theoretical Physics, Berkeley



My Favorite Annoying Elegant Explanation: Quantum Theory .......General Relativity, in turn, is only a classical theory. It rests on a demonstrably false premise: that position and momentum can be known simultaneously. This may a good approximation for apples, planets, and galaxies: large objects, for which gravitational interactions tend to be much more important than for the tiny particles of the quantum world. But as a matter of principle, the theory is wrong. The seed is there. General Relativity cannot be the final word; it can only be an approximation to a more general Quantum Theory of Gravity.

But what about Quantum Mechanics itself? Where is its seed of destruction? Amazingly, it is not obvious that there is one. The very name of the great quest of theoretical physics—"quantizing General Relativity"—betrays an expectation that quantum theory will remain untouched by the unification we seek. String theory—in my view, by far the most successful, if incomplete, result of this quest—is strictly quantum mechanical, with no modifications whatsoever to the framework that was completed by Heisenberg, Schrödinger, and Dirac. In fact, the mathematical rigidity of Quantum Mechanics makes it difficult to conceive of any modifications, whether or not they are called for by observation.

Yet, there are subtle hints that Quantum Mechanics, too, will suffer the fate of its predecessors. The most intriguing, in my mind, is the role of time. In Quantum Mechanics, time is an essential evolution parameter. But in General Relativity, time is just one aspect of spacetime, a concept that we know breaks down at singularities deep inside black holes. Where time no longer makes sense, it is hard to see how Quantum Mechanics could still reign. As Quantum Mechanics surely spells trouble for General Relativity, the existence of singularities suggests that General Relativity may also spell trouble for Quantum Mechanics. It will be fascinating to watch this battle play out.



President, The Royal Society; Professor of Cosmology & Astrophysics; Master, Trinity...

Physical Reality Could Be Hugely More Extensive Than the Patch of Space and Time Traditionally Called 'The Universe' .....As an analogy (which I owe to Paul Davies) consider the form of snowflakes. Their ubiquitous six-fold symmetry is a direct consequence of the properties and shape of water molecules. But snowflakes display an immense variety of patterns because each is molded by its distinctive history and micro-environment: how each flake grows is sensitive to the fortuitous temperature and humidity changes during its growth.

If physicists achieved a fundamental theory, it would tell us which aspects of nature were direct consequences of the bedrock theory (just as the symmetrical template of snowflakes is due to the basic structure of a water molecule) and which cosmic numbers are (like the distinctive pattern of a particular snowflake) the outcome of environmental contingencies. .


Theoretical physicist

An Explanation of Fundamental Particle Physics That Doesn't Exist Yet.....What is tetrahedral symmetry doing in the masses of neutrinos?! Nobody knows. But you can bet there will be a good explanation. It is likely that this explanation will come from mathematicians and physicists working closely with Lie groups. The most important lesson from the great success of Einstein's theory of General Relativity is that our universe is fundamentally geometric, and this idea has extended to the geometric description of known forces and particles using group theory. It seems natural that a complete explanation of the Standard Model, including why there are three generations of fermions and why they have the masses they do, will come from the geometry of group theory. This explanation does not yet exist, but when it does it will be deep, elegant, and beautiful—and it will be my favorite.


Mathematician, Harvard; Co-author, The Shape of Inner Space

A Sphere....Most scientific facts are based on things that we cannot see with the naked eye or hear by our ears or feel by our hands. Many of them are described and guided by mathematical theory. In the end, it becomes difficult to distinguish a mathematical object from objects in nature.

One example is the concept of a sphere. Is the sphere part of nature or it is a mathematical artifact? That is difficult for a mathematician to say. Perhaps the abstract mathematical concept is actually a part of nature. And it is not surprising that this abstract concept actually describes nature quite accurately.



theoretical physicist; Professor, Department of Physics, University of California,...
 Gravity Is Curvature Of Spacetime … Or Is It?......We do not yet know the full shape of the quantum theory providing a complete accounting for gravity. We do have many clues, from studying the early quantum phase of cosmology, and ultrahigh energy collisions that produce black holes and their subsequent disintegrations into more elementary particles. We have hints that the theory draws on powerful principles of quantum information theory. And, we expect that in the end it has a simple beauty, mirroring the explanation of gravity-as-curvature, from an even more profound depth.



Albert Einstein Professor in Science, Departments of Physics and Astrophysical...
Quasi-elegance....As a young student first reading Weyl's book, crystallography seemed like the "ideal" of what one should be aiming for in science: elegant mathematics that provides a complete understanding of all physical possibilities. Ironically, many years later, I played a role in showing that my "ideal" was seriously flawed. In 1984, Dan Shechtman, Ilan Blech, Denis Gratias and John Cahn reported the discovery of a puzzling manmade alloy of aluminumand manganese with icosahedral symmetry. Icosahedral symmetry, with its six five-fold symmetry axes, is the most famous forbidden crystal symmetry. As luck would have it, Dov Levine (Technion) and I had been developing a hypothetical idea of a new form of solid that we dubbed quasicrystals, short for quasiperiodic crystals. (A quasiperiodic atomic arrangement means the atomic positions can be described by a sum of oscillatory functions whose frequencies have an irrational ratio.) We were inspired by a two-dimensional tiling invented by Sir Roger Penrose known as the Penrose tiling, comprised of two tiles arranged in a five-fold symmetric pattern. We showed that quasicrystals could exist in three dimensions and were not subject to the rules of crystallography. In fact, they could have any of the symmetries forbidden to crystals. Furthermore, we showed that the diffraction patterns predicted for icosahedral quasicrystals matched the Shechtman et al. observations. Since 1984, quasicrystals with other forbidden symmetries have been synthesized in the laboratory. The 2011 Nobel Prize in Chemistry was awarded to Dan Shechtman for his experimental breakthrough that changed our thinking about possible forms of matter. More recently, colleagues and I have found evidence that quasicrystals may have been among the first minerals to have formed in the solar system.

The crystallography I first encountered in Weyl's book, thought to be complete and immutable, turned out to be woefully incomplete, missing literally an uncountable number of possible symmetries for matter. Perhaps there is a lesson to be learned: While elegance and simplicity are often useful criteria for judging theories, they can sometimes mislead us into thinking we are right, when we are actually infinitely wrong.




Physicist, Harvard University; Author, Warped Passages; Knocking On Heaven's Door

The Higgs Mechanism......Fortunately that time has now come for the Higgs mechanism, or at least the simplest implementation which involves a particle called the Higgs boson. The Large Hadron Collider at CERN near Geneva should have a definitive result on whether this particle exists within this coming year. The Higgs boson is one possible (and many think the most likely) consequence of the Higgs mechanism. Evidence last December pointed to a possible discovery, though more data is needed to know for sure. If confirmed, it will demonstrate that the Higgs mechanism is correct and furthermore tell us what is the underlying structure responsible for spontaneous symmetry breaking and spreading "charge" throughout the vacuum. The Higgs boson would furthermore be a new type of particle (a fundamental boson for those versed in physics terminology) and would be in some sense a new type of force. Admittedly, this is all pretty subtle and esoteric. Yet I (and much of the theoretical physics community) find it beautiful, deep, and elegant.

Symmetry is great. But so is symmetry breaking. Over the years many aspects of particle physics were first considered ugly and then considered elegant. Subjectivity in science goes beyond communities to individual scientists. And even those scientists change their minds over time. That's why experiments are critical. As difficult as they are, results are much easier to pin down than the nature of beauty. A discovery of the Higgs boson will tell us how that is done when particles acquire their masses.



Professor of Quantum Mechanical Engineering, MIT; Author, Programming the Universe
 The True Rotational Symmetry of Space.....Although this excercise might seem no more than some fancy and painful basketball move, the fact that the true symmetry of space is rotation not once but twice has profound consequences for the nature of the physical world at its most microscopic level. It implies that 'balls' such as electrons, attached to a distant point by a flexible and deformable 'strings,' such as magnetic field lines, must be rotated around twice to return to their original configuration. Digging deeper, the two-fold rotational nature of spherical symmetry implies that two electrons, both spinning in the same direction, cannot be placed in the same place at the same time. This exclusion principle in turn underlies the stability of matter. If the true symmetry of space were rotating around only once, then all the atoms of your body would collapse into nothingness in a tiny fraction of a second. Fortunately, however, the true symmetry of space consists of rotating around twice, and your atoms are stable, a fact that should console you as you ice your shoulder.

Remember even though I pick some of these explanations does not mean I discount all others. It's just that some are picked for what they are saying in highlighted quotations. Lisi's statement on string theory is of course in my opinion far from the truth, yet,  he captures a geometrical truth that I feel exists.:) You sort of get the jest of where I am coming from in the summation of Paul Steinhardt

Tuesday, December 07, 2010

Cyclic model

Physical cosmology
WMAP 2010.png
Universe · Big Bang
Age of the universe
Timeline of the Big Bang
Ultimate fate of the universe
A cyclic model is any of several cosmological models in which the universe follows infinite, self-sustaining cycles. For example, the oscillating universe theory briefly considered by Albert Einstein in 1930 theorized a universe following an eternal series of oscillations, each beginning with a big bang and ending with a big crunch; in the interim, the universe would expand for a period of time before the gravitational attraction of matter causes it to collapse back in and undergo a bounce.

Contents

Overview

In the 1930s, theoretical physicists, most notably Albert Einstein, considered the possibility of a cyclic model for the universe as an (everlasting) alternative to the model of an expanding universe. However, work by Richard C. Tolman in 1934 showed that these early attempts failed because of the entropy problem that, in statistical mechanics, entropy only increases because of the Second law of thermodynamics.[1] This implies that successive cycles grow longer and larger. Extrapolating back in time, cycles before the present one become shorter and smaller culminating again in a Big Bang and thus not replacing it. This puzzling situation remained for many decades until the early 21st century when the recently discovered dark energy component provided new hope for a consistent cyclic cosmology.[2]

One new cyclic model is a brane cosmology model of the creation of the universe, derived from the earlier ekpyrotic model. It was proposed in 2001 by Paul Steinhardt of Princeton University and Neil Turok of Cambridge University. The theory describes a universe exploding into existence not just once, but repeatedly over time.[3][4] The theory could potentially explain why a mysterious repulsive form of energy known as the "cosmological constant", and which is accelerating the expansion of the universe, is several orders of magnitude smaller than predicted by the standard Big Bang model.

A different cyclic model relying on the notion of phantom energy was proposed in 2007 by Lauris Baum and Paul Frampton of the University of North Carolina at Chapel Hill.[5]

The Steinhardt–Turok model

In this cyclic model, two parallel orbifold planes or M-branes collide periodically in a higher dimensional space.[6] The visible four-dimensional universe lies on one of these branes. The collisions correspond to a reversal from contraction to expansion, or a big crunch followed immediately by a big bang. The matter and radiation we see today were generated during the most recent collision in a pattern dictated by quantum fluctuations created before the branes. Eventually, the universe reached the state we observe today, before beginning to contract again many billions of years in the future. Dark energy corresponds to a force between the branes, and serves the crucial role of solving the monopole, horizon, and flatness problems. Moreover the cycles can continue indefinitely into the past and the future, and the solution is an attractor, so it can provide a complete history of the universe.
As Richard C. Tolman showed, the earlier cyclic model failed because the universe would undergo inevitable thermodynamic heat death.[1] However, the newer cyclic model evades this by having a net expansion each cycle, preventing entropy from building up. However, there are major problems with the model. Foremost among them is that colliding branes are not understood by string theorists, and nobody knows if the scale invariant spectrum will be destroyed by the big crunch. Moreover, like cosmic inflation, while the general character of the forces (in the ekpyrotic scenario, a force between branes) required to create the vacuum fluctuations is known, there is no candidate from particle physics. [7]

The Baum–Frampton model

This more recent cyclic model of 2007 makes a different technical assumption concerning the equation of state of the dark energy which relates pressure and density through a parameter w.[5][8] It assumes w < -1 (a condition called phantom energy) throughout a cycle, including at present. (By contrast, Steinhardt-Turok assume w is never less than -1.) In the Baum-Frampton model, a septillionth (or less) of a second before the would-be Big Rip, a turnaround occurs and only one causal patch is retained as our universe. The generic patch contains no quark, lepton or force carrier; only dark energy - and its entropy thereby vanishes. The adiabatic process of contraction of this much smaller universe takes place with constant vanishing entropy and with no matter including no black holes which disintegrated before turnaround. The idea that the universe "comes back empty" is a central new idea of this cyclic model, and avoids many difficulties confronting matter in a contracting phase such as excessive structure formation, proliferation and expansion of black holes, as well as going through phase transitions such as those of QCD and electroweak symmetry restoration. Any of these would tend strongly to produce an unwanted premature bounce, simply to avoid violation of the second law of thermodynamics. The surprising w < -1 condition may be logically inevitable in a truly infinitely cyclic cosmology because of the entropy problem. Nevertheless, many technical back up calculations are necessary to confirm consistency of the approach. Although the model borrows ideas from string theory, it is not necessarily committed to strings, or to higher dimensions, yet such speculative devices may provide the most expeditious methods to investigate the internal consistency. The value of w in the Baum-Frampton model can be made arbitrarily close to, but must be less than, -1.

Notes

  1. ^ a b R.C. Tolman (1987) [1934]. Relativity, Thermodynamics, and Cosmology. New York: Dover. LCCN 34032023-{{{3}}}. ISBN 0486653838. 
  2. ^ P.H. Frampton (2006). "On Cyclic Universes". arΧiv:astro-ph/0612243 [astro-ph]. 
  3. ^ P.J. Steinhardt, N. Turok (2001). "Cosmic Evolution in a Cyclic Universe". arΧiv:hep-th/0111098 [hep-th]. 
  4. ^ P.J. Steinhardt, N. Turok (2001). "A Cyclic Model of the Universe". arΧiv:hep-th/0111030 [hep-th]. 
  5. ^ a b L. Baum, P.H. Frampton (2007). "Entropy of Contracting Universe in Cyclic Cosmology". arΧiv:hep-th/0703162 [hep-th]. 
  6. ^ P.J. Steinhardt, N. Turok (2004). "The Cyclic Model Simplified". arΧiv:astro-ph/0404480 [astro-ph]. 
  7. ^ P. Woit (2006). Not Even Wrong. London: Random House. ISBN 97800994488644. 
  8. ^ L. Baum and P.H. Frampton (2007). "Turnaround in Cyclic Cosmology". Physical Review Letters 98 (7): 071301. doi:10.1103/PhysRevLett.98.071301. arXiv:hep-th/0610213. PMID 17359014. 

See also

Further reading

  • P.J. Steinhardt, N. Turok (2007). Endless Universe. New York: Doubleday. ISBN 9780385509640. 
  • R.C. Tolman (1987) [1934]. Relativity, Thermodynamics, and Cosmology. New York: Dover. LCCN 34032023-{{{3}}}. ISBN 0486653838. 
  • L. Baum and P.H. Frampton (2007). "Turnaround in Cyclic Cosmology". Physical Review Letters 98 (7): 071301. doi:10.1103/PhysRevLett.98.071301. arXiv:hep-th/0610213. PMID 17359014. 
  • R. H. Dicke, P. J. E. Peebles, P. G. Roll and D. T. Wilkinson, "Cosmic Black-Body Radiation," Astrophysical Journal 142 (1965), 414. This paper discussed the oscillatory universe as one of the main cosmological possibilities of the time.
  • S. W. Hawking and G. F. R. Ellis, The large-scale structure of space-time (Cambridge, 1973).

External links

Thursday, June 29, 2006

Early Universe Formation

An Energy of Empty Space?

Einstein was the first person to realize that empty space is not nothingness. Space has amazing properties, many of which are just beginning to be understood. The first property of space that Einstein discovered is that more space can actually come into existence. Einstein's gravity theory makes a second prediction: "empty space" can have its own energy. This energy would not be diluted as space expands, because it is a property of space itself; as more space came into existence, more of this energy-of-space would come into existence as well. As a result, this form of energy would cause the universe to expand faster and faster as time passes. Unfortunately, no one understands why space should contain the observed amount of energy and not, say, much more or much less.


I had been doing some reading and some thoughts came to mind about the measures one may use to see how our universe is doing. While it is really early here for any great revelation :) it did seem that issues could arise in my mind, if we used the "distance" to measure what exactly the universe is doing.

A Determinism at Planck Scale?

I'll tell you why in a second and then leave for now, as I have to continue with finishing the "foundation" with my son. Getting ready for backfilling tomorrow.



Andrey Kravtsov's computer modelling comes to mind, and how I was percieving early universe modelling in terms of a supersymmetrical state of existance. Holding this very idea in terms of this whole universe, it seemed to me, that the very "dynamical situation" and rise from such motivations, would have revealled principles as inherent in how "GR" would arise from this beginning. If the 5d consideration ha dbeen reduced to the 4 spacertime coordinated frame of reference, then what use any supersymmetrical state, or the motivation for such universe expressions?

Scientists have detected a flash of light from across the Galaxy so powerful that it bounced off the Moon and lit up the Earth's upper atmosphere. The flash was brighter than anything ever detected from beyond our Solar System and lasted over a tenth of a second. NASA and European satellites and many radio telescopes detected the flash and its aftermath on December 27, 2004. Two science teams report about this event at a special press event today at NASA headquarters


So there are two issues here that in my mind which make measurement extremely difficult. Two events within each other, that reveal something acute about the closeness of the beginnings in the universe, as very closely mappped to what exists now in our views revealled in GRB events



It was further complicated in my mind by two more issues that hold reference to these high energy events releases, that layout the schematics drawings, that the new WMAP indication holds in regards to analogistical sounds, revealled as the underpinnings of movement within this same universe.

So what about the WMAP and it's current reveallings?

If such equillibrium states are recognized as they are in placing detectors to position. Wouldn't this also reveal an opportune time for how we see this information, and provide for quick travel?

How did these "holes" create a problem for me?

If energy from these events found the "fastest route," then what would any lensing have looked like, effected by the very influences that the photon's travelled held, unduly holding to a fifth dimensional view?

The universe may of then looked like a swiss cheese? :)

Within conventional big bang cosmology, it has proven to be very difficult to understand why today's cosmological constant is so small. In this paper, we show that a cyclic model of the universe can naturally incorporate a dynamical mechanism that automatically relaxes the value of the cosmological constant, including contributions to the vacuum density at all energy scales. Because the relaxation time grows exponentially as the vacuum density decreases, nearly every volume of space spends an overwhelming majority of the time at the stage when the cosmological constant is small and positive, as observed today.


Link for article above here. Paul Steinhardt's homepage here.

If gravity and light are joined in the fifth dimension, what would this mean?

Wednesday, June 29, 2005

Science and it's Geometries?

On the post preceding this one, although we talked about the nature of the symmetries in action, and within context of the Calabi Yau, there is a relatiosnhip that must be drawn to other quarters of our perceptions to help orientate not only this drive for understanding energy production, but it's basis in geometry as well.

The cyclical notion driving Turok and Steinhardt, had to be found in our meddling with the likes of M theory and the brane world happenings with those points? How could such a dynamcical world arise from such a point, and it leads into all kinds of wonderful journies of the abstract. What will we find those who hold tightly to the rail from seeing width and depth, as one looks over this large abyss called the Grand Canyon.



When a gas bubble in a liquid is excited by ultrasonic acoustic waves, it can emit short flashes of light suggestive of extreme temperatures inside the bubble. These flashes of light, known as 'sonoluminescence', occur as the bubble implodes, or cavitates. Now Didenko and Suslick show that chemical reactions occur during cavitation of a single, isolated bubble,and they go on to determine the yield of photons, radicals, and ions formed. (Photo credit: Kenneth S. Suslick and Kenneth J. Kolbeck)







Today's agreement to build the ITER project in Cadarache, France, is an important milestone for Europe. It is not only the energy sector that will benefit from this decision: I expect ITER to also boost widespread positive consequences in areas like nanotechnology or material research. ITER will hugely benefit our Lisbon goals, creating more jobs, more research and more global competitiveness", said today Paul Rübig MEP (A), EPP-ED spokesman in the Committee on Industry, Technology, Research and Energy (ITRE) of the European Parliament


You see it's just more then a issue about fusion? :) Any "cyclical nature" that would exemplfy not only the universe, but models of geometry used, "theoretically must be" very important from those other mathematical perspectives.

If such a exchange, as a blackhole could arise from such a collapse, no longer able to fuel it's momentum outward as the sun in expression, then how so the collapse of the blackhole now representing the fusion that drives the energy in our sun? Our universe? You see such a trait in most universal design, and in the production of energy, had to be drawn for perspective to recognize motivations to the extent this universe would turn back on itself?

How strange indeed, then that this universe rapidly expanding, might signal the inevitable collapse that we might have seen in the suns, could also point towards a deeper comprehension of our own universe in action??

Energy in/Energy out, and if you ignite the process, how would sustain it? Compression factors in blackholes, contain a lot of potential, and if you turn them inside/out, this strange speculation rises about the energy/matter relation?


The Universe as an ecosystem: Much like biologists, astronomers trace the flow of matter and energy from one form to another in order to understand the dynamics of the entire system and how it evolves. (Credit: L. Whitlock (GSFC))


Well, microstate blackholes are in production, as well as events going on in nature. So the sun is of value in other ways, that the colliders can't touch, but on a value largely reduced from the energies needed from that same sun? You see, you would need quite a large collider that could not exist here on earth?:)

There is of course a fear of the blackhole production as well, but such collapse would be significant and part of the larger understanding of what is natural in our daily lives.

Pierre Auger is very instrumental in understanding this design?:)



See:

  • Bubble Nucleation
  • Saturday, December 18, 2004

    Warped Field Creates Lensing

    The statement of this post, is distilled from the collaboration of some of the images to follow.



    In cosmic string developement there are these three points to consider.

  • 1. Cosmological expansion

  • 2. Intercommuting and Loop Production

  • 3. Radiation




  • I am always looking for this imagery that helps define further what gravitational lensing might have signified in our perception of these distances in space. How the cosmic string might have exemplified itself in some determination, as we find Lubos has done in the calculation of the mass and size of this early event. This image to follow explains all three developemental points.



    Bashing Branes by Gabriele Veneziano
    String theory suggests that the big bang was not the origin of the universe but simply the outcome of a preexisting state

    The pre–big bang and ekpyrotic scenarios share some common features. Both begin with a large, cold, nearly empty universe, and both share the difficult (and unresolved) problem of making the transition between the pre- and the post-bang phase. Mathematically, the main difference between the scenarios is the behavior of the dilaton field. In the pre–big bang, the dilaton begins with a low value--so that the forces of nature are weak--and steadily gains strength. The opposite is true for the ekpyrotic scenario, in which the collision occurs when forces are at their weakest.

    The developers of the ekpyrotic theory initially hoped that the weakness of the forces would allow the bounce to be analyzed more easily, but they were still confronted with a difficult high-curvature situation, so the jury is out on whether the scenario truly avoids a singularity. Also, the ekpyrotic scenario must entail very special conditions to solve the usual cosmological puzzles. For instance, the about-to-collide branes must have been almost exactly parallel to one another, or else the collision could not have given rise to a sufficiently homogeneous bang. The cyclic version may be able to take care of this problem, because successive collisions would allow the branes to straighten themselves.




    The most strongest image that brought this together for me was in understanding what Neil Turok and Paul Steinhardt developed for us. It was watching the animation of the colliding branes that I saw the issue clarify itself. But before this image deeply helped, I saw the issue clearly in another way as well.

    The processes of intercommuting and loop production.

    It was very important from a matter distinction, to understand the clumping mechanism that reveals itself, after this resulting images of the galaxy formation recedes in the colliding brane scenrio viewing. If such clumping is to take place, we needed a way in which to interpret this.




    Branes Reform Big Bang By Atalie Young