Here is some information on the big collision hypothesis and a link to the page. Google Paul Steinhardt and Neil Turok, the creators of this idea for more information. Steinhardt and Turok also wrote a popular account in book form. I suggest that we read it next for the book club, since it gives a hypothetical answer as to what happened before the big bang.
http://www.actionbioscience.org/newfrontiers/steinhardt.html The cyclic universe model In this context, a new paradigm has been recently proposed by Paul Steinhardt (Princeton) and Neil Turok (Cambridge) —the cyclic universe — that turns the conventional picture topsy-turvy.2 (Perhaps the model should be called an old paradigm since it reinvigorates ancient cosmic mythologies and philosophies, albeit using the tools of 21st century physics.) In this picture: · space and time exist forever · the big bang is not the beginning of time; rather, it is a bridge to a pre-existing contracting era · the Universe undergoes an endless sequence of cycles in which it contracts in a big crunch and re-emerges in an expanding big bang, with trillions of years of evolution in between · the temperature and density of the universe do not become infinite at any point in the cycle; indeed, they never exceed a finite bound (about a trillion trillion degrees) · no inflation has taken place since the big bang; the current homogeneity and flatness were created by events that occurred before the most recent big bang · the seeds for galaxy formation were created by instabilities arising as the Universe was collapsing towards a big crunch, prior to our big bang The new model provides insight into some questions unanswered by the Big Bang theory. The prospects for an alternative cosmology that is so different from the well-The prospects for an alternative cosmology that is so different from the well-established convention would seem extremely dim. Yet, the cyclic model recoups all of the successful predictions of the big bang/inflationary theory and has sufficient additional predictive power to address many questions which the big bang/ inflationary model does not address at all: · What occurred at the initial singularity? · What is the ultimate fate of the Universe? · What is the role of dark energy and the recently observed cosmic acceleration? · Does time, and the arrow of time, exist before the big bang? or after the big crunch? In the new paradigm, each cycle proceeds through a period of radiation and matter domination consistent with standard cosmology, producing the observed primordial abundance of elements, the cosmic microwave background, the expansion of galaxies, etc. For the next trillion years or more, the Universe undergoes a period of slow cosmic acceleration (as detected in recent observations1), which ultimately empties the Universe of all of the entropy and black holes produced in the preceding cycle and triggers the events that lead to contraction and a big crunch. Note that dark energy is not simply added on — it plays an essential role. The transition from big crunch to big bang automatically replenishes the Universe by creating new matter and radiation. Gravity and the transition from big crunch to big bang keep the cycles going forever. In fact, as will be discussed, the cyclic behavior is a strong attractor. That is, even if the Universe were disrupted from its periodic behavior, it would rapidly reconverge to the cyclic solution. In the new paradigm, each cycle proceeds through a period of radiation and matter domination consistent with standard cosmology, producing the observed primordial abundance of elements, the cosmic microwave background, the expansion of galaxies, etc. For the next trillion years or more, the Universe undergoes a period of slow cosmic acceleration (as detected in recent observations1), which ultimately empties the Universe of all of the entropy and black holes produced in the preceding cycle and triggers the events that lead to contraction and a big crunch. Note that dark energy is not simply added on — it plays an essential role. The transition from big crunch to big bang automatically replenishes the Universe by creating new matter and radiation. Gravity and the transition from big crunch to big bang keep the cycles going forever. In fact, as will be discussed, the cyclic behavior is a strong attractor. That is, even if the Universe were disrupted from its periodic behavior, it would rapidly reconverge to the cyclic solution. Superstring theory and the cyclic universe The linchpin to the new paradigm is the transition from big crunch to big bang. The transition was thought to be an impossible passage in which the laws of physics blow up. However, recent developments in superstring theory suggest that the cosmic singularity is otherwise, as the two authors have argued in a recent paper with Justin Khoury (Princeton), Burt Ovrut (Penn) and Nathan Seiberg (IAS).3 Superstring theory relies on the idea that the Universe contains nine or ten spatial dimensions, depending on the formulation, all but three of which are curled up in a compact manifold of microscopic size. In this framework, the big bang and big crunch may be an illusion. Expressed in the usual variables of general relativity, it may appear that our usual space and time are disappearing. However, viewed with the proper variables, our usual space dimensions actually remain infinite and time runs continuously. The transition from big crunch to big bang is due, instead, to the collapse, bounce and re-expansion of one of the extra dimensions. For example, in a variant known as M theory: · the Universe consists of two branes (surfaces) bounding an extra dimension, and the singularity corresponds to a collision and bounce of the two branes · the temperature and density of ordinary radiation and matter remain finite at the bounce, and particles move continuously in a natural and intuitive way New cosmological possibilities If superstring theory is proven to dispel the myth that the big bang is the beginning of time, then it opens up new possibilities for the cosmological history of the Universe. Six months ago, the “ekpyrotic model”4 was proposed by Khoury, Ovrut, Steinhardt and Turok as one new possibility based on the idea of making a universe from a single collapse of the extra dimension. The cyclic model builds on lessons learned from the ekpyrotic example to produce a picture with remarkable predictive and explanatory power. © 2002, Paul J. Steinhardt, Ph.D. An update by the author of a previously published paper from his personal web page. See reprint policy. Paul J. Steinhardt, Ph.D., is a theoretical physicist in the departments of Physics and Astrophysical Sciences at Princeton University. His research spans problems in cosmology, astrophysics, particle physics and condensed matter physics. He is a leading expert on inflationary cosmology and other events in the very early universe. His work led to the first inflationary models for the universe, to the discovery that inflation can seed galaxy formation, and to new observational tests. He also introduced the concept of quasicrystals and pioneered the study of their structural and elastic properties. Prior to his position at Princeton, Dr. Steinhardt served as the Mary Amanda Word Professor of Physics at the University of Pennsylvania. He is a member of the National Academy of Sciences, a Fellow of the American Physics Society, and a member of the American Astronomical Society. http://www.physics.princeton.edu/www /jh/research/ steinhardt_paul.html --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Memphis Freethought Alliance" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/memphisfreethoughtalliance?hl=en -~----------~----~----~----~------~----~------~--~---
