which is true?

Elianna · February 16, 2009

1. the universe has always existed or
2. the universe has not always existed.
very well, let's take this one
I don't know why everyone is complaining about this question, it's just asking what people think with the understanding it's a total guess based on feelings and that no one has anything to back up their guess. I would say it has always existed.

He was right of course that your original post was not an 'or' type question. It's like asking am I good at bridge or bad at chess? Hmm, maybe both, maybe neither.

I understood it as a strangely worded 'or' type question. Helene basically already said it, but I think that "cause" was meant as "start", not "reason". Therefore, he's asking "did the universe have a beginning or did it always exist", which makes sense.

This is just my guess.

And so we're on the first page and we're having a debate about the meaning of the word "cause".

jdonn · February 16, 2009

And so we're on the first page and we're having a debate about the meaning of the word "cause".

Inevitable. :)

luke warm · February 16, 2009

1. the universe has always existed or
2. the universe has not always existed.
very well, let's take this one
Before the big bang, no information is available. Fun to speculate about, maybe, but what does it really matter?

it's a philosophical/logical question, more than anything else, but even people in other disciplines (hawking as an example) think on it

kenberg · February 16, 2009

1. the universe has always existed or
2. the universe has not always existed.
very well, let's take this one
Before the big bang, no information is available. Fun to speculate about, maybe, but what does it really matter?
it's a philosophical/logical question, more than anything else, but even people in other disciplines (hawking as an example) think on it

IN this revised formulation I take it to be a scientific question. Fifty some years ago when I first started reading about such things there were scientists, for example, George Gamow who thought the universe had begun with a big bang and others, for example Fred Hoyle who thought it had existed forever. Gamow's view was, I think, always the one with the strongest support but now, as I understand it, the big bang view is pretty much universally accepted, with the time being some 13 billion years. This time estimate has also changed over the years. That's the way with science.

There is a scientific way to interpret the (reformulated) question and a scientific way to come to agreement on the answer.

The original formulation asked if there was a cause. Whatever sense can be made out of that version of the question, it seems completely impossible to ever offer any evidence or argument to support any view. The discussion goes: There must have been a cause and so there is a God. No, there is no God and there was no cause. Oh yes there is. Oh no there isn't. My mother told me there is. Your mother is an idiot.

The arguments can be polite or not, sophisticated or not, but they will all end, or not end, without anyone changing his mind.

PassedOut · February 16, 2009

it's a philosophical/logical question, more than anything else, but even people in other disciplines (hawking as an example) think on it

No doubt someday physicists will work out a model or two that can explain the big bang, as it is indeed interesting. The question is one of physical reality, not of logic or philosophy.

My personal "worldview" accounts for the fact that many questions have not yet been answered and that some may never be answered. It can be fun to speculate about them and even daydream about them, as we all do, but speculation and daydreams are not answers.

blackshoe · February 16, 2009

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. :)

helene_t · February 16, 2009

Fifty some years ago when I first started reading about such things there were scientists, for example, George Gamow who thought the universe had begun with a big bang and others, for example Fred Hoyle who thought it had existed forever.

How can those two be alternative viewpoints, given, as Wackojack explains, that time began with the big bang? Was the question if the age of the universe is finite or infinite?

kenberg · February 16, 2009

Fifty some years ago when I first started reading about such things there were scientists, for example, George Gamow who thought the universe had begun with a big bang and others, for example Fred Hoyle who thought it had existed forever.
How can those two be alternative viewpoints, given, as Wackojack explains, that time began with the big bang? Was the question if the age of the universe is finite or infinite?

Yes, that's what I meant: Finite or infinite age. Hoyle's steady state envisioned a universe that was here x years ago where x is any number you like. Or so I understood it.

I suppose one could still try for some sort of framework where time before the Big Bang might be meaningful. For example, suppose we could see that eventually, in some number of years, there will be a Big Collapse. We could speculate that there is some sort of cyclic occurrence and number the cycles forwards and backwards. We could speak of, say, three and a half BCs ago, where a BC is the time from Bang to Collapse. I am NOT suggesting anyone spend time on this but I suppose that it is not completely out of the question that one could make some sense of such a statement. I don't know the current thinking about eventual collapse but that's a science issue. Whether a collapse would be followed by a new bang is somewhat more iffy as a scientific question it seems to me but perhaps something could be said. Running the experiment would be challenging.

I don't see that one can do much more than this, and even this is pushing the limits.

mike777 · February 16, 2009

If this doesn't blow your socks off, then Hogan, who has just been appointed director of Fermilab's Center for Particle Astrophysics, has an even bigger shock in store: "If the GEO600 result is what I suspect it is, then we are all living in a giant cosmic hologram."

The idea that we live in a hologram probably sounds absurd, but it is a natural extension of our best understanding of black holes, and something with a pretty firm theoretical footing. It has also been surprisingly helpful for physicists wrestling with theories of how the universe works at its most fundamental level.

http://www.newscientist.com/article/mg2012....html?full=true

TimG · February 16, 2009

Fifty some years ago when I first started reading about such things there were scientists, for example, George Gamow who thought the universe had begun with a big bang and others, for example Fred Hoyle who thought it had existed forever.
How can those two be alternative viewpoints, given, as Wackojack explains, that time began with the big bang? Was the question if the age of the universe is finite or infinite?

Can't "the age of the universe is finite" and "the universe existed before time began" both be true?

helene_t · February 16, 2009

"Before time began" lol.

jdonn · February 16, 2009

Fifty some years ago when I first started reading about such things there were scientists, for example, George Gamow who thought the universe had begun with a big bang and others, for example Fred Hoyle who thought it had existed forever.
How can those two be alternative viewpoints, given, as Wackojack explains, that time began with the big bang? Was the question if the age of the universe is finite or infinite?
Can't "the age of the universe is finite" and "the universe existed before time began" both be true?

The second one can't be true or false, since it is meaningless.

jdonn · February 16, 2009

Fifty some years ago when I first started reading about such things there were scientists, for example, George Gamow who thought the universe had begun with a big bang and others, for example Fred Hoyle who thought it had existed forever.
How can those two be alternative viewpoints, given, as Wackojack explains, that time began with the big bang? Was the question if the age of the universe is finite or infinite?
Can't "the age of the universe is finite" and "the universe existed before time began" both be true?

The second one can neither be true nor false, since it is meaningless. There's a sense in which the first is meaningless too, come to think of it.

helene_t · February 16, 2009

[....]Can't "the age of the universe is finite" and "the universe existed before time began" both be true?
The second one can neither be true nor false, since it is meaningless. There's a sense in which the first is meaningless too, come to think of it.

In what sense is "the age of the universe is finite" meaningless?

I think it could be meaningless if one could choose to scale time such that it could be either finite or infinite, depending on the scaling. Intuitively, we think of our time scale as non-arbitrary (up to a multiplicative constant) but that is just because intuitively we require the physical constants to be, well, constant. As I understand it, some cosmological models involve changing physical constants. Which makes me wonder if we can choose which constants to allow to be non-constant and thereby which time-scale to use.

jdonn · February 16, 2009

[....]Can't "the age of the universe is finite" and "the universe existed before time began" both be true?
The second one can neither be true nor false, since it is meaningless. There's a sense in which the first is meaningless too, come to think of it.
In what sense is "the age of the universe is finite" meaningless?

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.

I'm quite sure I agree with your lol that something 'existing before time began' truly is meaningless.

helene_t · February 16, 2009

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 · February 16, 2009

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 · February 16, 2009

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 · February 16, 2009

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 · February 16, 2009

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 · February 16, 2009

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 · February 16, 2009

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 · February 16, 2009

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

mike777 · February 16, 2009

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.