Paul J. Steinhardt, Neil Turok

EndlessUniverseAfter the lecture, both of us converged on Ovrut from different directions. No one can recall who blurted it out first, but one of us asked, “Can’t these worlds move along the extra dimension? And, if so, is it possible that the big bang is nothing more than a collision between these two worlds?” It became immediately clear that we had been struck with the same vision. Ovrut’s compelling conceptual picture suggested that the big bang might not be the “beginning” of the universe after all, but instead a physically explicable event with a “before” and an “after.” Furthermore, if there was no inflation to spread apart and dilute the matter and structures produced at the collision and one could observe them today, there might even be direct observational evidence of events that had occurred before the big bang.

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1 Response to Paul J. Steinhardt, Neil Turok

  1. shinichi says:

    Endless Universe: Beyond the Big Bang

    by Paul J. Steinhardt, Neil Turok

    (pp. 14-15) In this version of string theory, the ordinary three-dimensional “world” – everything in the universe that can be touched, felt, or seen – is separated from another inaccessible three-dimensional “world” by a tiny gap along a fourth dimension that cannot be experienced … the two worlds are totally disconnected from each other except for one factor: they interact through the force of gravity … the big bang is nothing more than a collision between these two worlds” .

    (p. 60) The big bang was triggered by the decay of dark energy that existed before the bang.

    (p. 155) The cyclic universe can be built from two braneworlds drawn together by a spring like force and colliding at regular intervals.

    (p. 156) When the separation hits zero, the branes collide in a big crunch, followed by a big bang as the branes separate once again.

    (p. 164) First, from string theory and M theory come the ideas of branes and extra dimensions, which allow for a big bang where the density of matter and radiation is finite. Second, observations of the present universe indicate the existence of a form of energy, dark energy, that is ideal for smoothing and flattening the universe. The same dark energy acting before the big bang could explain why the universe is smooth and flat on large scales today. Finally, the decay of the dark energy leads to a build-up of energy sufficient to power the big bang, while simultaneously generating density variations that can give rise to galaxies after the bang.

    (p. 226) There are no rigorous physical principles that dictate how to go from “nothing” to “something” … It seems far more plausible that our universe was the result of universe reproduction than that it was created by a unique cosmic event.

    (p. 241) The cyclic model is a self-reproducing cosmology.

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