[helene_t]

jdonn, on Feb 16 2009, 06:15 PM, said:

It involves accepting the idea of existence outside the universe. I think of the universe as the 'area' (for lack of a better word') inside which there is all existence. But I'm not saying that means the question must be meaningless, just that someone can reasonably think it is.

No, it does not have anything to do with existence outside the universe (which I agree with you makes no sense).

Assuming there are no issues with choice of time scale, it is a meaningful question whether the time that has ever elapsed is finite (say 13 billion years) or infinite. I think. It could also be that we can't know if there was anything before the big bang and that that question is meaningless. But as I understand the current thinking, time began with the big bang so there was no before. The time that has elapsed so far is finite.

[jdonn]

helene_t, on Feb 16 2009, 12:33 PM, said:

jdonn, on Feb 16 2009, 06:15 PM, said:

It involves accepting the idea of existence outside the universe. I think of the universe as the 'area' (for lack of a better word') inside which there is all existence. But I'm not saying that means the question must be meaningless, just that someone can reasonably think it is.

No, it does not have anything to do with existence outside the universe (which I agree with you makes no sense).

If that's your belief then you are suggesting something came from nothing. I think. But I'm certainly no expert in this type of thinking.

[helene_t]

jdonn, on Feb 16 2009, 06:39 PM, said:

If that's your belief then you are suggesting something came from nothing.

No, it is possible that there has always been matter (or at least energy, whatever) in the universe. The question I was addressing was whether "always" means the last say 13 billion years (since that is all the time there has been) or whether it means that last infinity of years.

[luke warm]

helene_t, on Feb 16 2009, 12:43 PM, said:

jdonn, on Feb 16 2009, 06:39 PM, said:

If that's your belief then you are suggesting something came from nothing.

No, it is possible that there has always been matter (or at least energy, whatever) in the universe. The question I was addressing was whether "always" means the last say 13 billion years (since that is all the time there has been) or whether it means that last infinity of years.

i think we've been here before, helene, but can an actual infinity exist (i don't mean conceptually, i mean in reality)

[Lobowolf]

blackshoe, on Feb 16 2009, 10:30 AM, said:

kenberg, on Feb 16 2009, 08:20 AM, said:

as I understand it, the big bang view is pretty much universally accepted, with the time being some 13 billion years.

True. Although... if you listen to the little ditty at the beginning of the sitcom The Big Bang Theory you'll hear "nearly 14 million years ago...". If Sheldon, one of the characters on the show, a severely OCD theoretical physicist, heard that, he'd have a fit.

"Nearly 14 billion" is an overbid. Science has definitively established the age of the universe, within 100 million years.

[jdonn]

I don't remember when I heard this, but I'm under the impression that the universe has continually expanded and contracted and 'big banged' into another version of the universe multiple times, and that we just really don't know about anything from before the last big bang. Did I just imagine that?

[mikeh]

jdonn, on Feb 16 2009, 01:30 PM, said:

I don't remember when I heard this, but I'm under the impression that the universe has continually expanded and contracted and 'big banged' into another version of the universe multiple times, and that we just really don't know about anything from before the last big bang. Did I just imagine that?

Or were you there?

One speculation that has attracted some interest is that black holes are actually the source of new universes, each with slightly different properties than the 'parent' universe. The idea is that this would give rise to evolution of universes (no, I am not making this up in order to make this thread another evolution thread.. this is a legitimate proposal put forward, admittedly as speculation, by legitimate physicists).

We understand that the current universe has certain parameters that, if altered to any significant degree, would result in a lack of stars, or a lack of matter at all: the ratios between the various forces that 'crystallized' out when the average temperature of the universe cooled following the big bang can't be altered to any real degree without causing the universe to be utterly different, and probably incapable of forming life as we understand the term.

The idea is that only those universes having parameters close to ours will be able to spawn black holes.. and the more black holes a universe can spawn, the more 'descendant' universes it will have. And as each descendant universe is presumed to have slightly different properties, over an immensity of time, an outside observer (if there were such a thing) would see more and more universes that have properties like the one we inhabit... and this in turn 'explains' why our particular universe is as it is... in essence, if it weren't, we wouldn't be here to wonder at it. And, over time, most of the possible universes will be similar to ours.

I gather that there is serious doubt as to whether this idea can, even in principle, be shown to reflect 'reality', but there is some chance that the math will prove to be valid

If this is so, then maybe the big bang was actually the formation of a black hole in some other universe... I gather that there is the same breakdown in theory at our understanding of the very first trillionth of a trillionth of a second after the big bang as there is about our understanding of what 'happens' in the heart of a black hole.

[Winstonm]

Question: If light cannot escape a black hole, doesn't that make a black hole when viewed from the outside timeless?

[mike777]

Something may be emitted.


Hawking radiation (also known as Bekenstein-Hawking radiation) is a thermal radiation with a black body spectrum predicted to be emitted by black holes.



The Hawking radiation process reduces the mass of the black hole and is therefore also known as black hole evaporation.

Because Hawking radiation allows black holes to lose mass,


http://en.wikipedia....wking_radiation

Of course if the Universe is a hologram then.....



"Which is true?"

http://www.angelfire.com/oh2/peterr/hologr...ivereality.html

[blackshoe]

Lobowolf, on Feb 16 2009, 01:27 PM, said:

"Nearly 14 billion" is an overbid.

And "nearly 14 million" is a severe underbid.

The asteroid impact that wiped out the dinosaurs occurred about 65 million years ago. According to the ditty, that's before the Big Bang.

The WMAP estimation of the length of time since the big bang is (1.373 ± 0.012) × 10E10 years. That makes "nearly 14 billion years" close enough for practical purposes.

[TimG]

mikeh, on Feb 16 2009, 01:55 PM, said:

We understand that the current universe has certain parameters that, if altered to any significant degree, would result in a lack of stars, or a lack of matter at all:

Or, a lack of time?

[luke warm]

PassedOut, on Feb 16 2009, 08:25 AM, said:

well philosophy also concerns itself with physical reality, and logic is necessary for science...

[PassedOut]

luke warm, on Feb 16 2009, 06:36 PM, said:

well philosophy also concerns itself with physical reality, and logic is necessary for science...

I agree.

[helene_t]

mikeh, on Feb 16 2009, 07:55 PM, said:

jdonn, on Feb 16 2009, 01:30 PM, said:

I don't remember when I heard this, but I'm under the impression that the universe has continually expanded and contracted and 'big banged' into another version of the universe multiple times, and that we just really don't know about anything from before the last big bang. Did I just imagine that?

Or were you there?

One speculation that has attracted some interest is that black holes are actually the source of new universes, each with slightly different properties than the 'parent' universe.

I gather we both read about this in "The blind watchmaker". Anyway, a google on
evolution universe "big bang" "black hole" dawkins
gave a.o. http://www.mkzdk.org...her/cosmos.html
Not sure how serious this theory is taken by cosmologists. Sounds cute, though

[mikeh]

helene_t, on Feb 16 2009, 08:02 PM, said:

mikeh, on Feb 16 2009, 07:55 PM, said:

jdonn, on Feb 16 2009, 01:30 PM, said:

I don't remember when I heard this, but I'm under the impression that the universe has continually expanded and contracted and 'big banged' into another version of the universe multiple times, and that we just really don't know about anything from before the last big bang. Did I just imagine that?

Or were you there?

One speculation that has attracted some interest is that black holes are actually the source of new universes, each with slightly different properties than the 'parent' universe.

I gather we both read about this in "The blind watchmaker". Anyway, a google on
evolution universe "big bang" "black hole" dawkins
gave a.o. http://www.mkzdk.org...her/cosmos.html
Not sure how serious this theory is taken by cosmologists. Sounds cute, though

also, and more recently, The Elegant Universe, about string theory.. very well written

[helene_t]

mikeh, on Feb 17 2009, 03:29 AM, said:

also, and more recently, The Elegant Universe, about string theory.. very well written

Thanks, I will buy that book soon.