[QUOTE=David Simmons]
As it has been explained to me there is no edge, merely a limit beyond which we cannot see, sort of like a horizon.
The pretty-well-known-by-now expansion rate shows that the further away things are from us the faster they are receding from us. It turns out that by the time you get out about 14.5 billion light years their recession velocity is the speed of light. Even if there were more universe out there we can never see it because it would be ouside our light cone.
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This is called the Cosmic Event Horizon, and like the event horizon around a black hole, it occurs when light becomes “accelerated”, or more properly, redshifted to the point that it can no longer be seen past that boundary. Note that the CEH is somewhere around 45Bly away (and that applies not only to us but from any point in the Universe, assuming that the Hubble Constant is invariant), but when the light that we now see as the edge of the Universe was emitted, it was around 40Mly away, which is a consequence of space itself expanding. If that doesn’t bend your brain, I don’t think an acid trip will do you any harm.
As for this business about a center, the universe (which exists in 3 spatial dimenions plus one time dimension) does have one, but it’s not a point in space, it’s an initial point in time. As an analogy that we can cope with in our own understanding, which is limited to three spatial dimensions at any instant in time, think of two ants on the outer surface of a balloon. The balloon definitely has a center, but it’s not some place you can get to; it only existed at t=0, before inflation started. As inflation continues (with time being the radial distance between the center and the surface) the two ants are seperated from each other at an ever increasing rate proportional to their distance from each other. If the balloon expands fast enough (or the ants are slow enough) there are even places on the balloon they can never get to because the skin expands faster than they can move; eventually, the areas they can reach (corresponding to the “light cone” mentioned by David Simmons becomes a very small portion of the surface of the balloon. Hence, no physical center, even though you have an effective boundary or edge.
[QUOTE=essell]
I’d love to hear more on this.
It sounds more like an abstraction caused by human number system than a physical fact.
Can you explain?
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Because there’s no way to go expand a finite system–one in which you can count all of the objects or measure the distances–to an infinite system. The universe either started out of infinite size, and bigger or smaller have no rational meaning (though they still have application in areas of mathematics), or it was of finite size and has continued to expand by a finite amount, resulting in a larger but still measureable volume. Now, you can create discontinuities that are immeasurable and have infinitesmals, like dividing an integer by zero, but that’s just a mathematical inconvenience (and very likely doesn’t even technically exist within the universe), not a sudden growth from finite to infinite.
[QUOTE=Whammo]
I know i am going to get ass raped for this… however… this particular type of question is what makes me believe in the existence of a higher being. The deeper I delve into science… the more i am convinced that none of this could possibly be random. Now this is MY feeling and im not arguing anyone else’s feelings. But damn people there is so much we dont know. Sure in the future we will figure more things out.. but i bet they only lead to more questions. Do you think there will be a one sentence answer at the end of all the questions? I do.
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I’m not going to participate in an “ass rape”, but I’ll suggest that you are applying a misperception based upon a false application of the concept of “random”. In fact, there is very little about the physical world–perhaps nothing–that can be properly described as random, though there is much which is unpredictable. Physical phenomena, even fundamentally statistical phenomena like quantum mechanics, follow explicit laws, and all processes progress in an order from energy concentrations to the equilibrium of energy dispersal; this is sometimes crudely stated as going from order to disorder, which is true in a certain fashion, but this is a very simplistic and likely to be misinterpreted statement of the Second Law of Thermodynamics; there’s plenty of ways in which to create greater complexity via energy flow from the high to low reservoirs (which is a more generally accurate statement). Now, why these fundamental laws exist and how they work beyond the veil of the stochastic curtain of QM and statistical mechanics is unknown and perhaps unknowable; invoking a god of some sort is, well, no less supported than any other interpretation. But it does involved an added complication of some kind of intellect that exists outside the universe. We can’t say it’s wrong, but it isn’t really necessary nor does it do anything to complete our understand the world any more than sacrificing virgins to the Rain God makes the sky water our crops.
Stranger
