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Mailing List complex-science@necsi.org Message #9682 | |
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| [Tony Smith wrote] At any moment, our cosmos can be seen as bound by various event horizons: the Big Bang at the Hubble radius and many black holes within. Those event horizons are all very porous, but each in one direction, the CMB flux entering from (near) the Big Bang horizon and anything that strays too close exiting through the black hole horizons. [JMc] There are indeed these local and global event horizons. So the planck limit on observational certainty (quantum uncertainty) and the global limit of visible universe. They were of course once together, at the same scale, during the big bang, and have separated apart. To illustrate the porous nature of the global event horizon, light that during the early stages of the universe was outside our light cone later re-entered due to the deceleration of its expansion. And dark energy acceleration could send the information back the other way again. The same would be true of a feature like a black hole which would take away information from visibility, yet would eventually re-radiate it in a sufficiently cool universe. But are these the true boundaries of the universe as a system? They are practical "internalist" boundaries to our observation but Sung is probably thinking of the externalist view in which there is a whole universe (containing many lightcone sub-domains, such as the one we are centred in). This largest view may be infinite in extent (as flat space is infinite), or instead infinite and bounded in the sense a hypersphere is some definite size, yet without boundaries. And then at the lower bound, we can ask is the quantum realm itself porous? If we forget about local special features like a black hole, what is the general story for a point of naked vacuum with only its zero point virtual energy? Is this a leaky boundary? Why cannot there be something smaller, even lower energy? Personally, I like to think of these two contrasting "harder" boundaries in geometric terms. So it does seem likely the global shape of the universe is a closed hypersphere. It has a coherent curvature that completely connects it. And then the lower boundary can be modelled in complementary fashion as "completely hyperbolic". That is, instead of the negative curvature of a hypersphere, you have a positive curvature in which every point in spacetime would diverge away from all neighbouring points. A quantum foam in other words. Get down to the planck scale and you can't keep getting smaller (cross the boundary of scale to pop out the other side) because at that point spacetime breaks up as a coherent fabric and becomes a chaotic roil. Try to push smaller and you just go sideways, hyperbolically-speaking. This would describe the nature of the boundaries. Then there is the second question of whether the universe exists as an open or closed system? Conventional wisdom argues it is a closed system - a bubble that budded off from whatever was before/outside (ie: a spawning multiverse in a Smolin style approach) and which continues to swell inertially, under the weight of its own contents. It neither gains nor loses energy across a boundary. This conventional view is then modified by speculation that black holes could be the boundaries for fresh universes to bud off. So they form a singularity through which sufficient information flows (in one direction) to spark fresh budding events. This is a highly unlikely story to my mind. But that's another story. What would be interesting is the idea that the universe in fact still is an open system at its lower QM bound. That there is a leakiness. And I expect this may be where the dark energy story goes. Some small residual push is still feeding in from the planckscale, making the universe accelerate on top of its inertial expansion. This fits in nicely with far from equilibrium, steady-state dissipative structure thinking. And so I think it can be said that dark energy is a sign that the universe is almost very nearly closed, very nearly isolated, yet still transacts across its lower boundary. And so ultimately, a physical theory of everything (TOE) will have to be based on an open systems perspective, not a closed one. And the second law of thermodynamics would have to become then the first. Cheers - John McCrone ---------------------------------------------------- >> check out http://www.dichotomistic.com Dichotomistic - an introduction to organic logic and holistic causality |
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