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[QUOTE=petrw1;364680]If you do not believe then there had to have been a LONG time before t=0 for the stuff to collect.
Then I might ask how did that stuff come to be that began to collect?[/QUOTE]Analogous question: what is north of the north pole? |
[QUOTE=xilman;364681]Analogous question: what is north of the north pole?[/QUOTE]
Depends if you consider up as North. |
[QUOTE=xilman;364681]Analogous question: what is north of the north pole?[/QUOTE]
Not a legitimate analogy. The planets have a finite spatial extent. The Universe has an infinite temporal past. The planet allows for a unique spatial origin such as the north pole. But time goes back infinitely, so there is no unique t=0. And for @petrw1: yours is the right viewpoint. There had to have been a whole bunch of activity preceeding the so-called big bang, which therefore could not be considered the beginning. |
[QUOTE=petrw1;364682]Depends if you consider up as North.[/QUOTE]
Depends on your frame of reference. |
[QUOTE=petrw1;364680]Where did all that stuff come from that went BANG!!!!!!
If you believe in a Supreme Being ...[/QUOTE]The problem of infinite regress. If a deity created the "stuff" then who or what created the deity? And who or what created the who or what that created the deity? etc. etc. etc. |
[QUOTE=xilman;364681]Analogous question: what is north of the north pole?[/QUOTE]
Restricting ourselves to purely surface cartography, why the rest of the planet, my good sir. (Including the north pole, once on each lap). I.e. the same as what is south of the north pole, just with opposite traversal direction. Will we be coming or going today, sir? |
[QUOTE=retina;364698]The problem of infinite regress. If a deity created the "stuff" then who or what created the deity? And who or what created the who or what that created the deity? etc. etc. etc.[/QUOTE]
Exactly..... |
[QUOTE=ewmayer;364700]Restricting ourselves to purely surface cartography, why the rest of the planet, my good sir. (Including the north pole, once on each lap). I.e. the same as what is south of the north pole, just with opposite traversal direction. Will we be coming or going today, sir?[/QUOTE]Is the wrong answer for the right reason.
Once more, I was being too subtle for some readers. The north pole is not a physical singularity but a co-ordinate singularity. There is nothing north of the north pole because the very concept "north pole" depends on the choice of co-ordinates. However, there is nothing physically distinguished about the north pole --- the terrain there looks very much the same as it does in its neighbourhood and the rest of the planet is accessible along Ernst's (implied) geodesics. There is no physical singularity. Now compare models of the big bang. All have a singularity at t=0 and there is nothing at t<0. The traditional models have a physical singularity at t=0. This singularity perturbs some people because, almost by definition, it is difficult at least and arguably impossible to apply physical modelling there. Hawking's complex-time model argues that the singularity at t=0 is only a co-ordinate singularity analogous to the north pole on a sphere. The spacetime there looks very much the same as it does in its neighbourhood and the rest of the universe is accessible along Einstein's geodesics. Anyway, amusement aside, I really would like to read davar55's response to my question about why the present universe is so far from thermal equilibrium. Added in edit: just read Chalsall's contribution. He got it exactly right --- it really does depend on the choice of co-ordinates. Well done Sir! Someone at least is paying attention to what I mean. |
[QUOTE=retina;364698]The problem of infinite regress. If a deity created the "stuff" then who or what created the deity? And who or what created the who or what that created the deity? etc. etc. etc.[/QUOTE]
[QUOTE=petrw1;364707]Exactly.....[/QUOTE] Reexamine the word/concept "created" to resolve this. This line is proof that no deity created the Universe or anything else. But infinite regress has no inherent problem - the Universe as a whole must always have existed, but its contents are constantly being "redistributed" (at the smallest level) to produce things (such as stars and black holes and oranges). Infinite regress works as explanation for the Universe as a whole, which could not have had a cause "outside" of itself (there is no such place). Therefore time has an infinite past. QED (some steps placed elsewhere) :smile: |
[QUOTE=davar55;364775]QED (some steps placed elsewhere) :smile:[/QUOTE]
[QUOTE=xilman]Anyway, amusement aside, I really would like to read davar55's response to my question about why the present universe is so far from thermal equilibrium.[/QUOTE] I, also, would be interested in hearing davar55 answer to this serious question. |
[QUOTE=xilman;364734]Now compare models of the big bang. All have a singularity at t=0 and there is nothing at t<0.[/QUOTE]
But I made no such assumption about "models of earth's surface geography" - thus in my (and hopefully most major airlines') model, traversal to and beyond the north pole is permissible. Like you said, in that geometry the pole is just a designated "special point" having no special intrinsic-geometric properties whatsoever. The t=0 point in the big bang model(s) you refer to are quite different in that regard. |
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