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Originally posted by lemon limePerhaps if the universe is now infinite, it was at least once 'finite' when hypothetically 'viewed' from 'outside' it but was always 'infinite', i.e. never 'finite', when hypothetically 'viewed' from 'inside' itself i.e. from within it?
If our universe started with the big bang then how could it be infinite? Wouldn't it need to be infinite to begin with?
(This would imply that the singularity it came from can be 'infinite' in size when hypothetically 'viewed' from 'inside' itself but not from the outside)
-something like the TARDIS being larger on the inside than the outside except infinity involved?
ANYONE; does that above make any sense at all in conventional physics/cosmology theory?
Originally posted by humyNot to me. The universe doesn't have an outside nor can it be viewed from outside whether or not it is finite or infinite. I realize you put the words in quotes, but they must mean something and I can't think of a meaning for which they would make sense.
ANYONE; does that above make any sense at all in conventional physics/cosmology theory?
Originally posted by twhiteheadcouldn't another (hypothetical) universe other than our own be considered to be 'outside' of our own thus imply there is an 'outside' of our own?
Not to me. The universe doesn't have an outside nor can it be viewed from outside whether or not it is finite or infinite. I realize you put the words in quotes, but they must mean something and I can't think of a meaning for which they would make sense.
Originally posted by humyIts a tricky problem. I suppose so, but it must be very clear that it would not be outside in terms of spacial dimensions but be in a completely other dimension.
couldn't another (hypothetical) universe other than our own be considered to be 'outside' of our own thus imply there is an 'outside' of our own?
If you look at a numberline on a piece of paper you are outside the numberline, and you could draw other numberlines also completely disjoint form the first one. All the numberlines are theoretically infinite.
What you mustn't do is imagine the universe as a sphere with other universes being spheres in a larger space. That is not the case.
Originally posted by twhiteheadit is impossible to visualize separate universes with no spatial dimension between them but, as usual, just because we cannot visualize something doesn't mean it isn't true.
Its a tricky problem. I suppose so, but it must be very clear that it would not be outside in terms of spacial dimensions but be in a completely other dimension.
If you look at a numberline on a piece of paper you are outside the numberline, and you could draw other numberlines also completely disjoint form the first one. All the numberlines are theoreti ...[text shortened]... universe as a sphere with other universes being spheres in a larger space. That is not the case.
Originally posted by humyWhen I say 'no spatial dimension', I am referring to the three spatial dimensions we know. And it isn't true, not because its impossible to visualize, it isn't true because it violates the definition of 'universe'.
it is impossible to visualize separate universes with no spatial dimension between them but, as usual, just because we cannot visualize something doesn't mean it isn't true.
What I am saying is that the 3 spatial dimensions we know, are complete within this universe. They may be finite or infinite, but they do not have edges with a 'beyond'. If the universe is finite, you still could not travel to the edge of the universe and fall off, just as you cannot fall off the edge of the finite surface area of the earth. To view the Earth's surface you need a third dimension. to view the universe externally, you need more dimensions.
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Originally posted by twhiteheadSounds like our definition of 'universe' is at odds with reality.
When I say 'no spatial dimension', I am referring to the three spatial dimensions we know. And it isn't true, not because its impossible to visualize, it isn't true because it violates the definition of 'universe'.
What I am saying is that the 3 spatial dimensions we know, are complete within this universe. They may be finite or infinite, but they do not ...[text shortened]... s surface you need a third dimension. to view the universe externally, you need more dimensions.
If there was this 'big bang', as you say, a misnomer, It seems it would have to had come from a dimension outside our set of dimensions. How else would you frame the problem?
Like the hypothesis that the 'BB' was a black hole in a parent universe squirting mass, space, and time into what becomes our universe, a white hole on this side of reality, a black hole on that other dimension.
Originally posted by sonhouseWe simply don't know. The BB is a singularity.
Sounds like our definition of 'universe' is at odds with reality.
If there was this 'big bang', as you say, a misnomer, It seems it would have to had come from a dimension outside our set of dimensions. How else would you frame the problem?
We do not know if there was a 'before' or a 'came from'. We simply don't know anything whatsoever about it.
There is also no 'had to'.
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Originally posted by twhiteheadSomething squirting space into what becomes OUR dimension would seem to by definition need some other starting point, outside our existence. It didn't happen out of thin air so to speak.
We simply don't know. The BB is a singularity.
We do not know if there was a 'before' or a 'came from'. We simply don't know anything whatsoever about it.
There is also no 'had to'.
Or do you think it was the first non causal event in our universe?
Originally posted by sonhouseI think we don't know.
Something squirting space into what becomes OUR dimension would seem to by definition need some other starting point, outside our existence. It didn't happen out of thin air so to speak.
Or do you think it was the first non causal event in our universe?
If time extends before the BB, then so does space as they are intimately linked. If time does not extend before the BB, then yes, it was necessarily the first non-causal event in our universe.
I see no reason whatsoever to posit some other time-like dimension in which some cause-like events take place to create our universe. I cannot rule it out, but it would need some sort of evidence to be anything other than a wild hypothesis dreamed up because our understanding of our causally based universe makes us feel the need for causes even when there may be none.
I see no good reason to think that it didn't happen out of thin air - or more accurately, there was never any thin air, and it didn't so much 'happen' as 'just was'.
It seems to me that at least one brute fact is necessary for existence. We do not know what that brute fact is, or if there are others, but I see no reason why the universe's existence could not be a brute fact.
Originally posted by twhiteheadHere is one set of such evidence:
I think we don't know.
If time extends before the BB, then so does space as they are intimately linked. If time does not extend before the BB, then yes, it was necessarily the first non-causal event in our universe.
I see no reason whatsoever to posit some other time-like dimension in which some cause-like events take place to create our universe. I ...[text shortened]... if there are others, but I see no reason why the universe's existence could not be a brute fact.
Levi thinks he may have spotted a clue, however. He and two NYU colleagues note another strange anomaly embedded in the cosmic microwave background: In the southern hemisphere of the sky there is one cold spot that is much bigger than the rest. Levi’s calculations show that an ancient wallop from a neighboring universe could have created this spot. “It’s tough to explain with standard cosmology how such a cold spot could have come about,” he says.
The whole article:
http://discovermagazine.com/2009/oct/04-will-our-universe-collide-with-neighboring-one
When such evidence appears, cosmologists or theoretical physicists are hard pressed to come up with a scenario that would make such a large structure in the microwave background.
It lends support to the multiverse idea. At least there IS evidence, not pure speculation.