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Robert Tulip
2013-Nov-08, 01:43 AM
The Big Bang Theory posits expansion from an infinitesimal singularity.

Does this mean all the matter in the universe once had no size?

NoChoice
2013-Nov-08, 02:16 AM
It means first and foremost that we have absolutely no clue as to what was going on "back then".
We have no useful model for it.
The big bang is a very weak and primitive model full of ugly crutches.
It goes back to almost the singularity but then explicitly excludes it stating known physics was breaking down, leaving a pretty bad aftertaste.

It really is a bad model but all we seem to have at this point...

Noclevername
2013-Nov-08, 02:22 AM
It goes back to almost the singularity but then explicitly excludes it stating known physics was breaking down, leaving a pretty bad aftertaste.


That being the actual definition of a singularity, I see no reason for a "bad aftertaste".

Noclevername
2013-Nov-08, 02:39 AM
The Big Bang Theory posits expansion from an infinitesimal singularity.


That's not exactly what the BB posits. It states that the Universe began as hot and dense and expanded from there. This is supported by known observations of galaxies and the Cosmic Microwave Background, which appears to be residual heat from the earliest state of the Universe.

Jeff Root
2013-Nov-08, 03:31 AM
The Big Bang cosmology is derived primarily from the general
theory of relativity, which predicts a singularity at the beginning.
However, while general relativity has been found to be fully
accurate in every situation it has been tested in, the conditions
it predicts close to the singularity are incompatible with the
predictions of the theory of quantum mechanics, which has also
been found accurate in every situation tested. So we know that
something unknown was going on at the beginning. Either GR
or QM or both are incomplete or wrong, OR something else was
going on that is not part of either theory that prevented the two
theories from conflicting. For example, if the matter-energy of
the Universe increased as the Universe expanded, then the
density would not have been infinite at the singularity, and
GR's prediction would not conflict with QM, so both theories
could be completely correct and apply all the way back to
the singularity.

-- Jeff, in Minneapolis

pzkpfw
2013-Nov-08, 04:21 AM
I've always seen it (perhaps very mistakenly) as being like the difference between abiogenesis and evolution; including the way people sometimes lump the concepts together.

korjik
2013-Nov-08, 04:24 AM
The Big Bang cosmology is derived primarily from the general
theory of relativity, which predicts a singularity at the beginning.
However, while general relativity has been found to be fully
accurate in every situation it has been tested in, the conditions
it predicts close to the singularity are incompatible with the
predictions of the theory of quantum mechanics, which has also
been found accurate in every situation tested. So we know that
something unknown was going on at the beginning. Either GR
or QM or both are incomplete or wrong, OR something else was
going on that is not part of either theory that prevented the two
theories from conflicting. For example, if the matter-energy of
the Universe increased as the Universe expanded, then the
density would not have been infinite at the singularity, and
GR's prediction would not conflict with QM, so both theories
could be completely correct and apply all the way back to
the singularity.

-- Jeff, in Minneapolis

Incorrect. The big bang theory is based on observations of the universe today and running them back in time to see what happened long ago. The theory gets dodgy well before it runs into the GR/QM incompatability simply because we dont have a good Grand Unified Theory and as a result are pretty much guessing on the conditions once the energy reaches the point where electroweak should unify with the strong force.

We know from observation that there are certain properties that the early universe must have had. One of the earliest of these is the Cosmic Microwave Background, which puts strict restrictions on the properties of the early universe, mainly its 'flatness'. This implies that the early universe was very small and very dense. This then implys that the universe had an original volume of zero, giving a mathmatical singularity in density at t=0, but the laws of quantum mechanics break down and 10-43 seconds, so this isnt really a problem cause all the laws of physics have been tossed out the window anyway.

So, to the OP, yes, under current theory all the matter of the universe was at one zero volume point at t=0. It also says that point has expanded, so all the matter in the universe is still in that same point today, just the point is a bit bigger now.

PetTastic
2013-Nov-08, 11:46 AM
I sometimes like to think of it as, at t=0, the universe did not contain any normal 3 dimensional space.
The amount of space in the universe has been increasing ever since.

This causes problems for our normal view of physics based on matter, because modern matter is mostly space.

Cougar
2013-Nov-08, 01:25 PM
The big bang is a very weak and primitive model full of ugly crutches.

A statement like this must come from someone with a very weak and primitive understanding of the big bang theory.

Cougar
2013-Nov-08, 01:36 PM
The Big Bang Theory posits expansion from an infinitesimal singularity.

A "singularity" is not a thing. The word "singularity" means "Oops, the math we were using doesn't work anymore." ETA: That is, it is no longer applicable.


Does this mean all the matter in the universe once had no size?

Well, that wouldn't make much sense, would it? The answer is, we don't know! Like Carl Sagan said many years ago when the age of the universe was not so well constrained:



Ten or twenty billion years ago, something happened -- the Big Bang, the event that began our universe. Why it happened is the greatest mystery we know. That it happened is reasonably clear.


As far as having all the answers....



It is rather ironic that the job of a scientist is to understand nature, and if the scientist completely succeeds, the reward is unemployment. But of the many things that concern me in the day-to-day existence of a scientist, waking up one morning and discovering that there are no problems to solve is rather low on the list." [Rocky Kolb, Blind Watchers of the Sky]

Solfe
2013-Nov-08, 01:43 PM
"All of physics is solvable by pouring money into STE(A)M programs now." Perhaps this isn't true, but I fail to see a down side. :)

Cougar
2013-Nov-08, 01:51 PM
We know from observation that there are certain properties that the early universe must have had. One of the earliest of these is the Cosmic Microwave Background, which puts strict restrictions on the properties of the early universe, mainly its 'flatness'.

To clarify, the measured size of the largest fluctuations in the Cosmic Microwave Background indicate that the overall curvature of space within the Universe throughout its history, is flat.

Cougar
2013-Nov-08, 02:07 PM
....first and foremost that we have absolutely no clue as to what was going on "back then".

"Absolutely no clue"? Have you actually studied cosmology to any extent that would enable you to make such a claim? Most well studied cosmologists and astrophysicists are quite in agreement and have a good idea about the state of the Universe at one second after the "beginning." This is known mainly from the observed abundance of the elements and the CMB. It is only as we go from t=1 sec. to t=0 that our knowledge decreases exponentially.

Cougar
2013-Nov-08, 02:19 PM
The "exponental decrease" in our knowledge prior to one second after the big bang is actually pretty slow at first. It is my understanding that today's particle accelerators can simulate conditions that must have occurred when the Universe was 10-17 seconds old.

Shaula
2013-Nov-08, 02:33 PM
It means first and foremost that we have absolutely no clue as to what was going on "back then".
We have plenty of clues. Just no testable or fully worked out models.


The Big Bang Theory posits expansion from an infinitesimal singularity.

Does this mean all the matter in the universe once had no size?
FWIW I will repeat what I say every time these threads some up. The Big Bang theory contains no bang, no singularity. It states only that the observable universe grew from a hot, dense state a finite time in the past. So it does not say that matter once had no size.

There are several reasons it could not say that - matter, or what we normally call it, obeys Fermi-Dirac statistics. It cannot all be in one state. Since QM is part of the cosmological model we have at the moment it could not say that without being internally inconsistent. If we look at the energy of the universe, assuming by that we mean bosons it could be. But then we have the issue that we don't know of anything that violates CP enough to produce the matter/antimatter asymmetry we see. You can opt to ignore QM and try to say that "GR says this" but that is a bad way to go. The evidence for the Big Bang theory is largely a mix of QM and GR. To throw one away just so you can arbitrarily go back to t=0 is nonsense.

So you are left with this: there is a singularity if you carefully pick and chose when you want to pick up and put down the current theories. Otherwise you have to say that we do not know what happened right at what we extrapolate naively to be the start.

mkline55
2013-Nov-08, 03:37 PM
The "exponental decrease" in our knowledge prior to one second after the big bang is actually pretty slow at first. It is my understanding that today's particle accelerators can simulate conditions that must have occurred when the Universe was 10-17 seconds old.

"Must have occurred"? So it has been confirmed without any possibility of doubt that the conditions simulated by a particle accelerator are the exact conditions when the universe was 10-17 seconds old? While I realize that is the most popular belief, I remain skeptical that anyone knows with absolute certainty what "must have occurred". Replace "must" with "hypothetically", and I'm totally on board.

Cougar
2013-Nov-08, 08:34 PM
"Must have occurred"? So it has been confirmed without any possibility of doubt that the conditions simulated by a particle accelerator are the exact conditions when the universe was 10-17 seconds old?

Yes, pretty much. Of course, there is no "absolute certainty" in science, and skepticism is usually a good thing. But when you put all the observations together, all of them, and on top of that you do the math, the remaining doubt becomes very small that the state of the Universe was something entirely different than the simulations in the most powerful accelerators.

Jeff Root
2013-Nov-08, 10:48 PM
We have fairly good evidence that we know the conditions
about one minute after the Big Bang, because the ratios of
some hydrogen and helium isotopes are quite sensitive to
changes in those conditions. Earlier than that, we can only
extrapolate. We know we can't extrapolate all the way back
to time zero, because quantum mechanics becomes unusable
beyond the Planck era, but we have no clue at all just how far
back we can accurately extrapolate using only known physics.
At some point between one minute and the Planck era, new
physics becomes essential. We *can* extrapolate back to
times much less than a second, but we have no idea whether
the extrapolation becomes inaccurate close to the Planck era
or close to one minute.

-- Jeff, in Minneapolis

caveman1917
2013-Nov-09, 03:41 PM
That being the actual definition of a singularity, I see no reason for a "bad aftertaste".


A "singularity" is not a thing. The word "singularity" means "Oops, the math we were using doesn't work anymore." ETA: That is, it is no longer applicable.

The actual definition of a singularity is a region in a metric space where the metric tensor is singular, ie its determinant is zero, no more and no less.

Noclevername
2013-Nov-09, 05:37 PM
The actual definition of a singularity is a region in a metric space where the metric tensor is singular, ie its determinant is zero, no more and no less.

Yes, you're right. I sometimes forget I'm a layman.

Jeff Root
2013-Nov-09, 07:11 PM
Caveperson,

Can you explain why you said "region" rather than "point" or
the word I generally prefer to use, "place"?

-- Jeff, in Minneapolis

caveman1917
2013-Nov-09, 08:15 PM
Caveperson,

Can you explain why you said "region" rather than "point" or
the word I generally prefer to use, "place"?

-- Jeff, in Minneapolis

Because it doesn't have to be a point. For example, inside a rotating black hole there's a ring-shaped singularity.

Jeff Root
2013-Nov-09, 11:18 PM
I have read that before but it didn't make sense to me.
Can you say why the singularity is a ring rather than a disk?

The term "region" couldn't apply to the Big Bang sngularity,
though, could it? Certainly not a region in time, anyhow.

-- Jeff, in Minneapolis

LaurieAG
2013-Nov-10, 12:32 AM
Einsteins 1939 paper titled "On a Stationary System With Spherical Symmetry Consisting of Many Gravitating Masses" had the following comment at the end.


The essential result of this investigation is a clear understanding as to why the "Schwarzschild singularities" do not exist in physical reality. Although the theory given here treats only clusters whose particles move along circular paths it does not seem to be subject to reasonable doubt that most general cases will have analogous results. The "Schwarzschild singularity" does not appear for the reason that matter cannot be concentrated arbitrarily. And this is due to the fact that otherwise the constituting particles would reach the velocity of light. This investigation arose out of discussions the author conducted with Professor H. P. Robertson and with Drs. V. Bargmann and P. Bergmann on the mathematical and physical significance of the Schwarzschild singularity. The problem quite naturally leads to the question, answered by this paper in the negative, as to whether physical models are capable of exhibiting such a singularity

caveman1917
2013-Nov-10, 01:20 PM
I have read that before but it didn't make sense to me.
Can you say why the singularity is a ring rather than a disk?

That depends on how you mean that question. I can show you the math and you could see how you get a ring-shaped singularity rather than a disk-shaped one, but something tells me that is not what you intend with that "why" question. If you're asking if i can present you some general reasoning as to why it must be ring-shaped rather than disk-shaped then the answer is no, i cannot see anything wrong per se with a spacetime containing a disk-shaped singularity, it just doesn't happen to be the case with a rotating black hole. That doesn't mean that such an argument doesn't exist, maybe i'm overlooking something, but i wouldn't know of such an argument.


The term "region" couldn't apply to the Big Bang sngularity,
though, could it? Certainly not a region in time, anyhow.

What's in a word though? Is the point at the top of a cone a "region"? My choice of words was merely to make sure that it was clear that a singularity doesn't have to be a point, it can have other shapes too.

caveman1917
2013-Nov-10, 01:28 PM
Einsteins 1939 paper titled "On a Stationary System With Spherical Symmetry Consisting of Many Gravitating Masses" had the following comment at the end.

He made a reasoning error in that paper. What the paper shows is that inside a certain radius from a black hole there are no stable orbits, which Einstein interpreted as evidence for the non-existence of black holes, rather than just the fact that there are no stable orbits close to black holes. I think we even had a thread on that paper.

kevin1981
2013-Nov-10, 05:34 PM
The Big Bang Theory posits expansion from an infinitesimal singularity.

Does this mean all the matter in the universe once had no size?

The Big Bang Theory posits expansion from a hot dense state. The big bang theory has nothing to do with origins, but rather the evolution of the universe from that hot dense state.

I think of a singularity as a state, rather than an actual thing. A singularity is a state where we do not know what is going on.

We can not know if, all the matter in the universe once had no size. Our knowledge of what was going on breaks down.

Jeff Root
2013-Nov-10, 06:55 PM
Kevin,

I believe caveman1917 gave a pretty good definition of what a
singularity is in post #19. More generally, I'd say a singularity
is a place (not necessarily in space -- it could be in time or in
any kind of mathematical continuum) where some property or
properties of the continuum go to zero or infinity. So typically
it is a point. But as caveman **points** out, it doesn't have
to be a point. The event horizon of a black hole is a kind of
singularity, and that is a spherical surface. Chicago is a kind
of singularity of railroads, in that the railroads from the east
end there, and the railroads from the west end there. They
meet at that "point", but the tracks don't join together. It is
the zero point for going in either direction.

What caveman means by "metric space" may be exactly what
I mean by "continuum". A measurement space doesn't have
to literally be "space".

-- Jeff, in Minneapolis

publiusr
2013-Nov-10, 10:08 PM
When I think singularity, I think of Kursweil or Black Holes--another word for the "Cosmic egg" where all matter and space are lumped together was monobloc. I always loved that word.

Hornblower
2013-Nov-10, 11:53 PM
Kevin,

I believe caveman1917 gave a pretty good definition of what a
singularity is in post #19. More generally, I'd say a singularity
is a place (not necessarily in space -- it could be in time or in
any kind of mathematical continuum) where some property or
properties of the continuum go to zero or infinity. So typically
it is a point. But as caveman **points** out, it doesn't have
to be a point. The event horizon of a black hole is a kind of
singularity, and that is a spherical surface. Chicago is a kind
of singularity of railroads, in that the railroads from the east
end there, and the railroads from the west end there. They
meet at that "point", but the tracks don't join together. It is
the zero point for going in either direction.
What caveman means by "metric space" may be exactly what
I mean by "continuum". A measurement space doesn't have
to literally be "space".

-- Jeff, in Minneapolis

My bold. That is not a singularity. The fundamental conditions under which railroads can be built and operated are defined and determinate everywhere in the city. It was human policy-making to have the main lines terminate the way they do. As a matter of fact there are transfer tracks interconnecting the main lines so railroad cars can be run through without having to be unloaded.

Jeff Root
2013-Nov-11, 03:29 AM
Certainly the Chicago railroads is far from a perfect example,
but I think it is good enough for the purpose. I'm sure we can
both come up with better examples. I mainly was interested
in an example where the metric space isn't space, although I
didn't really accomplish that.

-- Jeff, in Minneapolis

Strange
2013-Nov-11, 09:34 AM
Can the north and south poles be considered analogous to singularities?

In the sense that you can't go further into the past than the big bang singularity (or further into the future than a black hole singularity) in the same way you can't go further north than the north pole...

Hornblower
2013-Nov-11, 12:41 PM
The poles are singularities in longitude, a quantity that becomes undefined at those points. These singularities are artifacts of the coordinate system and they go away if we transform to different coordinates. If I am not mistaken that can be done to facilitate navigation when near the poles. There is no physical barrier, and latitude remains explicitly defined at the pole.

Hornblower
2013-Nov-11, 02:35 PM
Certainly the Chicago railroads is far from a perfect example,
but I think it is good enough for the purpose. I'm sure we can
both come up with better examples. I mainly was interested
in an example where the metric space isn't space, although I
didn't really accomplish that.

-- Jeff, in Minneapolis

I think I am starting to see what you were trying as a thought exercise. I suppose we could create a mathematical space that is confined to railroad tracks, but I think it would be an unnecessary kludge. A Cartesian space in which all points in Chicago are explicitly defined is perfectly good for analyzing train movements and the obstacles to such movements.

In a sense I see a situation that is opposite that in post 32. Here we have physical obstacles to moving a train directly through Chicago, but there are no analytic booby traps anywhere in Chicago or anywhere else except at the poles. In post 32 we have an analytic booby trap at the pole, but no physical barrier to moving along a line that includes the pole.

Strange
2013-Nov-11, 03:44 PM
Do you think we could persuade all science journalists and writers to replace "singularity" with "analytical booby trap"?

kevin1981
2013-Nov-11, 05:50 PM
Kevin, More generally, I'd say a singularity
is a place (not necessarily in space -- it could be in time or in
any kind of mathematical continuum) where some property or
properties of the continuum go to zero or infinity.

Okay jeff, thanks. That has helped my understanding of what a singularity usually is. However, we can not extrapolate all the way back to T=0, so we do not know what went on. So, instead of saying we have infinite properties or "all matter was zero size", could we not get away with saying, in the instance of the big bang, that the singularity, is a state ?

Hornblower
2013-Nov-11, 07:03 PM
Okay jeff, thanks. That has helped my understanding of what a singularity usually is. However, we can not extrapolate all the way back to T=0, so we do not know what went on. So, instead of saying we have infinite properties or "all matter was zero size", could we not get away with saying, in the instance of the big bang, that the singularity, is a state ?

My bold. We do not say that. As I think I understand it, that is a misconception that is perpetuated by bad writing on the topic, or by misinformed word of mouth to which such bad writing is a contributing factor.

kevin1981
2013-Nov-11, 08:02 PM
Jeff wrote it.

More generally, I'd say a singularity
is a place (not necessarily in space -- it could be in time or in
any kind of mathematical continuum)where some property or
properties of the continuum go to zero or infinity.


I am not trying to argue for the sake of it, i am just trying to further me understanding. Which is at the moment, that the BB singularity is a state, where we do not know what is happening, rather than what Jeff describes it at.



Does this mean all the matter in the universe once had no size?

I also wrote it because Robert Tulip mentioned it. So i am suggesting that the BB singularity after our physics break down, is a state, rather than a place where properties go to infinity and matter may or may not have zero size.

Jeff Root
2013-Nov-12, 12:50 AM
At the moment, I see three possibilities. There are almost
certainly many others I'm not seeing.

1) The Big Bang started at a singularity. That is, it began
at a definite moment. That is the simple prediction of GR.

2) The Big Bang sort of started at a singularity. That is, we
can trace the evolution of the Universe back in time to some
moment, but the beginning before that was kinda fuzzy, and
took some time to get going.

3) The Big Bang was an event in eternal inflation, which was
going on long before the Big Bang, and maybe forever, so
there was no singularity, just an inflation.

-- Jeff, in Minneapolis

NoChoice
2013-Nov-12, 03:09 AM
The big bang is a very weak and primitive model full of ugly crutches.

A statement like this must come from someone with a very weak and primitive understanding of the big bang theory.

Clearly, you haven't thought this through.

The main question that is at the root of most people's interest in science is to gain a better understanding of this world and the core questions are (certainly for me and most people I know):
1. How did all of the universe and everything in it come to be?
2. Why?

The 2nd is not in the domain of science but the first one is.

The BB model is very weak because it is incapable to answer the question of the origin at t=0.
It is primitive because it cannot answer many questions that arise from within it. One of the most prominent being: Where is all the damn anti-matter??
It uses ugly crutches like spontaneous and unexplained sudden inflation by a huge factor (10^78 or more) in an extremely short time. That was just thrown in there to make it all fit (somewhat).

Yes, it has some predictive power but in my book any model that cannot reach back to t=0 (btw: that's what I meant when I said "back then") is entirely unsatisfactory for me.

I'm not blaming anybody for it. In fact, it is quite amazing what a primitive species like homo sapiens has accomplished in the last few hundred years.

However, the fact remains: It is entirely obvious that we haven't understood fundamental properties and processes of the universe because our models are way too primitive and incomplete and full of ugly crutches.

If you find this satisfactory be my guest. I certainly don't.

noncryptic
2013-Nov-12, 04:56 AM
The BB model is very weak because it is incapable to answer the question of the origin at t=0.

Which is why what happened at t=0 is not part of the scientific standard model.

Everything else about the "big bang model" (generally: expansion of the universe) is quite strong.


It is entirely obvious that we haven't understood fundamental properties and processes of the universe

That much is obvious.


because our models are way too primitive and incomplete

Do you mean the models being "primitive and incomplete" is the cause of our lack of fundamental understanding, or that being incomplete is an indicator of our lack of fundamental understanding? In case of the latter that seems just a different way of saying that we don't fully understand. Also, it is already known that it is not fully understood.


and full of ugly crutches.

The theories that underpin the standard model are incomplete, but not full of ugly crutches.

Beyond that, it is not exactly news nor controversial that science has not figured everything out, in other words: that the theories are not complete.



i am suggesting that the BB singularity after our physics break down, is a state...

Given that it is those 'broken physics' theories that tell us there is a singularity, how likely it is to be a correct prediction?

In hindsight i suppose that's sort of what you are saying, by calling it a "state" rather than a thing or place.

Shaula
2013-Nov-12, 06:31 AM
The BB model is very weak because it is incapable to answer the question of the origin at t=0.
This is not a weakness of the BB model, it is a weakenss of Quantum Mechanics and GR. They are where things go wrong.


It is primitive because it cannot answer many questions that arise from within it. One of the most prominent being: Where is all the damn anti-matter??
Outside the BB model. This is a weakness of the Standard Model, that there are no know strong enough CP violating processes to account for this.


It uses ugly crutches like spontaneous and unexplained sudden inflation by a huge factor (10^78 or more) in an extremely short time. That was just thrown in there to make it all fit (somewhat).
It was thrown in there to fit the data, this is how you refine a theory. Is the Standard Model ugly because it needed the Higgs, Strange quarks, third generation leptons to work properly? Did it suddenly become pretty when we found them?

You may not like it but scientifically it is the current theory for a resaon - it fits the data best. Maybe it will all be thrown out, maybe not. People do look for alternatives. And if they find one I am sure someone out there will think it is ugly.

NoChoice
2013-Nov-12, 07:03 AM
This is not a weakness of the BB model, it is a weakenss of Quantum Mechanics and GR. They are where things go wrong.

I know. Most of the math the BB model is based is derived from QM and GR. So, yes, at the end of the day it's the incompleteness of those that leads to the flaws in the BB model.



Outside the BB model. This is a weakness of the Standard Model, that there are no know strong enough CP violating processes to account for this.
Yes. See above.



It was thrown in there to fit the data, this is how you refine a theory. Is the Standard Model ugly because it needed the Higgs, Strange quarks, third generation leptons to work properly? Did it suddenly become pretty when we found them?
Yes, I find the standard model ugly. And no, I certainly do not think it has become pretty with finding more "particles". I find the particle zoo most unsatisfactory. We are clearly missing something very fundamental.
I understand the process. Those are crutches nonetheless.


You may not like it but scientifically it is the current theory for a resaon - it fits the data best. Maybe it will all be thrown out, maybe not. People do look for alternatives. And if they find one I am sure someone out there will think it is ugly.
I understand that it's the current model for a reason. I have no objection to the lack of knowledge we have. How could I?

I do object, however, to the glary-eyed adoration it receives from some who think we have pretty much nailed it except for some little math problem around the singularity issue.
The flaws are much more fundamental than that. I know (or rather strongly suspect) that you are very aware of that and so are quite a few others on this board.

And it is because I am aware of the fundamental flaws and lack of understanding we have that I am virtually certain we need a fundamentally different approach, despite the fact that the current models have a rather amazing predictive power. It almost feels like the universe is teasing us. Bloody bugger!

I believe the missing link in all this is consciousness. Unless we find a way to incorporate that in some way, we will remain stuck.

Shaula
2013-Nov-12, 07:37 AM
I believe the missing link in all this is consciousness. Unless we find a way to incorporate that in some way, we will remain stuck.
I don't see the need for a personal sense of beauty about a physical model, to be honest. But I was not in strong disagreement with you until this bit. I see no reason to believe that a universe that was around before there were any complex structures requires an emergent property of pseudo-Hebbian networks to function. Will you find the 'conciousness zoo' as ugly as the particle zoo if we find aliens?

Anyway, the point is that your criticisms are not based on science and the other parts of your objection are based on pointing out the known incompleteness of human knowledge. Neither of which are grounds to declare the BB theory as weaker than any other physical theory out there.

Hopefully I am not counted as being among those bewitched by what is, essentially, just our best model so far. It has problems and is incomplete, it may need to be adjusted or thrown out entirely. But when it is it has to be on the basis of another model being better not an appeal to aesthetics or unsupported guesswork. That way lies String theory! (could not resist)

Strange
2013-Nov-12, 09:19 AM
The BB model is very weak because it is incapable to answer the question of the origin at t=0.

That is equivalent to the standard creationist argument that evolution is wrong because we can't yet explain abiogenesis. In other words, it says nothing at all about about the value of the theory.

Strange
2013-Nov-12, 09:20 AM
I believe the missing link in all this is consciousness. Unless we find a way to incorporate that in some way, we will remain stuck.

Please don't bring your mystical experiences into it again.

NoChoice
2013-Nov-12, 10:36 AM
Please don't bring your mystical experiences into it again.

Worry not, son.

And since I am now - according to your truly amazing powers of deductive reasoning - a creationist, a biblical quote seems in order:
I won't "cast pearls before swine" - again.

tusenfem
2013-Nov-12, 11:05 AM
Worry not, son.
I won't cast pearls before swine - again.


Okay, are you continuing to be rude all the time?
infraction

Cougar
2013-Nov-12, 01:01 PM
The actual definition of a singularity is a region in a metric space where the metric tensor is singular, ie its determinant is zero, no more and no less.

That would seem to ensure, for most people anyway, that the concept of a singularity remains uncomprehended.

Strange
2013-Nov-12, 01:24 PM
And since I am now - according to your truly amazing powers of deductive reasoning - a creationist

I didn't say that. I was simply pointing out the flaw in your argument.

Cougar
2013-Nov-12, 01:25 PM
The BB model is very weak because it is incapable to answer the question of the origin at t=0.
It is primitive because it cannot answer many questions that arise from within it. One of the most prominent being: Where is all the damn anti-matter??
It uses ugly crutches like spontaneous and unexplained sudden inflation by a huge factor (10^78 or more) in an extremely short time. That was just thrown in there to make it all fit (somewhat).

Yes, it has some predictive power but in my book any model that cannot reach back to t=0 (btw: that's what I meant when I said "back then") is entirely unsatisfactory for me....

However, the fact remains: It is entirely obvious that we haven't understood fundamental properties and processes of the universe because our models are way too primitive and incomplete and full of ugly crutches.

In other words, the glass is half empty. You're generally right, of course, but your language is so hyperbolic, as in hyperbole. Instead of "the theory has its weaknesses," you say the entire theory is "very weak." The theory is quite well developed and on solid foundations, but you call it "primitive." I guess that's a relative word. Primitive to whom? An advanced alien race? Probably so.


I'm not blaming anybody for it. In fact, it is quite amazing what a primitive species like homo sapiens has accomplished in the last few hundred years.

That's what I notice. By golly, there's water in that glass. Does labeling humans as primitive really add anything to this impression?

kevin1981
2013-Nov-12, 06:44 PM
3) The Big Bang was an event in eternal inflation, which was
going on long before the Big Bang, and maybe forever, so
there was no singularity, just an inflation.

I have read about eternal inflation but did not realise that there is no need for a singularity. That is interesting, maybe there was not a singularity in the first place !

Getting back to my "singularity is a state" idea.. I think of a black hole singularity as a state, rather that a place where everything is crushed into a point, the size of an atom. It is a state, where we do not know what is going on.

niteskye
2013-Nov-12, 09:01 PM
Yes, It seems to me that a singularity is a 'state' or event that occurs at a 'place'. A 'state' is a completed point in a process or occurance and a snapshot of what is, concievably, a single moment in a much larger journey and series of states. At what point/age does a singularities 'state' stop being a 'place' in our observability. Does it achieve a point at which we can no longer 'prove' it's existsence?

NEOWatcher
2013-Nov-13, 01:51 PM
At what point/age does a singularities 'state' stop being a 'place' in our observability.
It breaks down when the mathematics of it can no longer define it.

(I hope I'm using the right terminology, it's been decades since I was proficient at my field of study)

In some cases, it is as simple as when something goes to infinity or zero in differential calculus type of computations.
In other cases, it involves issues that arise when the equations involve ordinal sets of numbers. In the case of the big bang, this involves the ordinal set of numbers that are multiples of Planck units.

pzkpfw
2013-Nov-13, 11:22 PM
Kind of just throwing this out there, but (as I didn't spot it being noted), isn't it thought that the observable Universe isn't the whole Universe?

So - when we talk about the "size" of the Universe moments after the Big Bang, we're talking about the "size" of our observable Universe at that "time", not the "size" of the "whole" Universe?

(This was pointed out to me on a long-ago thread here, and it certainly changed the way I thought about the issue.)

Jeff Root
2013-Nov-14, 03:02 AM
Different people mean different things when they talk about
"the size" of the Universe. Different people mean different
things when they talk about "the Universe". I mean different
things at different times when I talk about "the Universe".

One might mean...

- Everything observable with current techniques

- Everything observable in principle at the current time

- Everything observable in principle by a given observer
over the entire history of the Universe, past and future

- Everything ever causally connected to the observer, past
or future

- Everything involved in the Big Bang

- Everything involved in eternal inflation, including other
universes in a multiverse

- Everything, whether part of "the multiverse" or not

I might mean any of those when I say "the Universe", and
others probably have other meanings I haven't thought of.

-- Jeff, in Minneapolis

pzkpfw
2013-Nov-14, 04:14 AM
Yep, and if everyone is thinking different things, doesn't that make the discussion harder? Maybe some more rigour is needed on definitions (and answers).

noncryptic
2013-Nov-14, 05:39 AM
Yes, It seems to me that a singularity is a 'state' or event that occurs at a 'place'. A 'state' is a completed point in a process or occurance and a snapshot of what is, concievably, a single moment in a much larger journey and series of states. At what point/age does a singularities 'state' stop being a 'place' in our observability. Does it achieve a point at which we can no longer 'prove' it's existsence?

Scientifically the only way to "prove" the existence of anything is observation. But the singulatity "exists"/"is" only in metric space. Metric space is a mathematical concept, not physical spacetime.

WayneFrancis
2013-Nov-14, 09:06 AM
No because of 2 reasons. First the universe might be infinite in size or finite. If the former then it was always infinite in size when the were even spatial dimension to consider. Second if the universe is finite it is still very large. At very beginning there was only energy in the three spatial dimensions. The early universe either way had to go through a rapid inflation before the energy density was low enough to allow matter to form.

Noclevername
2013-Nov-14, 12:39 PM
No because of 2 reasons.

Which post are you saying no to?

Cougar
2013-Nov-14, 01:25 PM
But the singulatity "exists"/"is" only in metric space. Metric space is a mathematical concept, not physical spacetime.

Well, AFAIK, a metric space just means a space within which you can measure distances -- a space where the measurement of distance is well defined.

kevin1981
2013-Nov-14, 06:19 PM
Kind of just throwing this out there, but (as I didn't spot it being noted), isn't it thought that the observable Universe isn't the whole Universe?

So - when we talk about the "size" of the Universe moments after the Big Bang, we're talking about the "size" of our observable Universe at that "time", not the "size" of the "whole" Universe?


Thanks for bringing this up as i have a question i would like to ask.

I found this quote on line..


Its possible that the universe was infinite at the big bang and so it will still be infinite now. When cosmologists say the universe is expanding what they mean is the distance between galaxies is growing over time; not that the universe has a certain known size which is growing over time. When they say the universe was small at the big bang they mean the "observable universe" which does have a known size and is growing over time.

How do we explain the universe being infinite at the big bang ? Is that suggesting our big bang took place in a preceding space ? Or is it suggesting that there was nothing and then the universe became infinite in an instant. I find it hard to comprehend the latter as it had a beginning so how could it go on forever.. ?

Thanks, Kevin

Noclevername
2013-Nov-14, 06:25 PM
How do we explain the universe being infinite at the big bang ? Is that suggesting our big bang took place in a preceding space ? Or is it suggesting that there was nothing and then the universe became infinite in an instant. I find it hard to comprehend the latter as it had a beginning so how could it go on forever.. ?


I don't find an infinite universe suddenly springing from nothing to something, any harder to visualize than a finite universe suddenly springing from nothing to something. It would require everything coming into existence everywhere at once instead of only at one location. Physics is sometimes counter-intuitive that way, it works in ways we find hard to imagine.

pzkpfw
2013-Nov-14, 06:39 PM
Thanks for bringing this up as i have a question i would like to ask.

I found this quote on line..



How do we explain the universe being infinite at the big bang ? Is that suggesting our big bang took place in a preceding space ? Or is it suggesting that there was nothing and then the universe became infinite in an instant. I find it hard to comprehend the latter as it had a beginning so how could it go on forever.. ?

Thanks, Kevin

Say our current visible Universe is found to be on a streteched rubber sheet. And say we know the rest of the Universe goes on infinitely long, on infinite stretched rubber sheet.

Because we can detect the sheet is stretched we extrapolate that in the past it wasn't stretched, and we figure out that our visible Universe used to be much smaller. (And hot and dense).

Any observer in the infinite Universe can figure that their "own" piece of visible Universe used to be a very small (hot dense) bit of un-stretched rubber sheet.

So the current infinite stretched rubber sheet used to be an infinite un-stretehced rubber sheet.


And that's the distinction I was trying to make. We know our visible Universe "came from" a very very small very hot dense thing (extrapolating back beyond that is where we find the singularity). That very very small very hot dense thing was where our visible Universe "came from", and if our (entire) Universe is infinite that doesn't mean it all came from that same very very small very hot dense thing; the hot dense thing was itself infinite; a small piece of it is what is now our visible Universe - other observers in a non-overlapping visible Universe of their own would have their own origin point.

Hot dense: .....
Expanded: OOOOO

Anyway, that's how it was (more or less) explained to me.

P.S. I'm not saying this is the "truth" or the reality, it's just how I understand one concept. Whether it's "right" ... ?

pzkpfw
2013-Nov-14, 06:45 PM
I don't find an infinite universe suddenly springing from nothing to something, any harder to visualize than a finite universe suddenly springing from nothing to something. It would require everything coming into existence everywhere at once instead of only at one location. Physics is sometimes counter-intuitive that way, it works in ways we find hard to imagine.

Isn't "from nothing" a common misconception? Isn't it more: "we don't really know yet"?

Noclevername
2013-Nov-14, 06:48 PM
Isn't "from nothing" a common misconception? Isn't it more: "we don't really know yet"?

See? It is hard to understand! ;)

kevin1981
2013-Nov-14, 07:16 PM
I just thought i would mention, yes, i do understand that this is all complete speculation of one concept out of many.

pzkpfw Are you suggesting that the universe was already infinite and expanding and our own visible universe expanded from a small singularity in pre existing, expanding space ?



See? It is hard to understand! ;)

You're telling me !

pzkpfw
2013-Nov-14, 07:43 PM
I just thought i would mention, yes, i do understand that this is all complete speculation of one concept out of many.

pzkpfw Are you suggesting that the universe was already infinite and expanding and our own visible universe expanded from a small singularity in pre existing, expanding space ? ...

This concept (which I don't say is "right" or "wrong") is that the Universe was already infinite, and is still infinite. It's just much less dense now.

(Like having the entire set of integers written down (yes, it's infinite so you couldn't ...) then all the numbers get an extra space between them. You might wonder where all the "extra" paper came from, but it was already infinite. {It hurts my head. My personal "view" is different, but not scientific so I won't raise it.})

caveman1917
2013-Nov-14, 08:33 PM
I mainly was interested
in an example where the metric space isn't space, although I
didn't really accomplish that.

The space of all polynomials of degree n with the Euclidean metric would do. Say if n=2 we have the space of ax^2 + bx + c for all real triplets (a,b,c). Being denoted by triplets (a,b,c) this should remind you of Euclidean 3-space with (x,y,z), and as such we can use the same metric. Actually these spaces are isomorphic (in as much as they are vector spaces - ie including addition and scalar multiplication).

caveman1917
2013-Nov-14, 09:05 PM
That would seem to ensure, for most people anyway, that the concept of a singularity remains uncomprehended.

I would argue the opposite, looking past the "a singularity is when the math stops working" explanation is how you can comprehend what a singularity is. The math is working just fine, the problem is that a singularity (being a region/place/whatever - if you want to be strict about it call it a subset of the space - where the metric tensor becomes singular ) creates a point of geodetic incompleteness. What this means is that the evolution equations of a particle, when it reaches the singularity, do not uniquely determine the future of the particle anymore.

Perhaps a simplified analogy would help. Suppose that the position x of a particle at some time is given by the equation ax + 5 = 5 for some parameter a. A singularity would be a place where a=0 (you can even think of a as a 1x1 matrix that becomes singular at a=0). What happens now is that you can't uniquely determine x from that equation anymore, since for 0x + 5 = 5 every real number x is a solution. That doesn't mean that the math suddenly stopped working, it's doing just fine - the solution to that equation is the set of real numbers. It just doesn't give the solution you would want, a unique one, which is physically speaking a big issue - not mathematically speaking though.

* or where the metric tensor simply stops existing due to having infinite components, i forgot that case earlier, which would in our analogy be like having a be infinite.

caveman1917
2013-Nov-14, 09:14 PM
No because of 2 reasons. First the universe might be infinite in size or finite. If the former then it was always infinite in size when the were even spatial dimension to consider.

It turns out that there exist some inflation models in which the size of the universe diverges in finite time, essentially going from finite size to infinite size in finite time. Though AFAIK those are not the "standard" inflation models, and i'm not sure how exactly it would work.

caveman1917
2013-Nov-14, 09:20 PM
I suppose we could create a mathematical space that is confined to railroad tracks, but I think it would be an unnecessary kludge. A Cartesian space in which all points in Chicago are explicitly defined is perfectly good for analyzing train movements and the obstacles to such movements.

Actually a graph (http://en.wikipedia.org/wiki/Graph_%28mathematics%29) might be a very good model for railroad tracks. You could probably make that into a metric space by assigning weights to the edges according to spatial distance between nodes and then take the minimum of the sum of weights over all connections between two nodes as the metric distance.

noncryptic
2013-Nov-15, 02:46 PM
> metric space is a mathematical concept, not physical spacetime.

Well, AFAIK, a metric space just means a space within which you can measure distances -- a space where the measurement of distance is well defined.

"In mathematics, a metric space is a set where a notion of distance (called a metric) between elements of the set is defined."
http://en.wikipedia.org/wiki/Metric_space

Cougar
2013-Nov-16, 01:41 AM
What this means is that the evolution equations of a particle, when it reaches the singularity, do not uniquely determine the future of the particle anymore.

Excellent clarification. Thank you.

WayneFrancis
2013-Nov-19, 05:36 AM
Which post are you saying no to?

The OP

WayneFrancis
2013-Nov-19, 05:43 AM
T...

How do we explain the universe being infinite at the big bang ? Is that suggesting our big bang took place in a preceding space ? Or is it suggesting that there was nothing and then the universe became infinite in an instant. I find it hard to comprehend the latter as it had a beginning so how could it go on forever.. ?

Thanks, Kevin

How do you explain the universe being finite at the big bang? It would just be the existing state. If you want to travel back in "time" before the big bang and ask how can something can go from zero volume to infinite volume then you have to ask how it could go from zero volume to a finite volume. The transition seems just as puzzling.

Think of it this way ... something can have a start but go on forever. Time for instance. It can have a beginning point but still could be infinite unless you want to propose a mechanism for time to "end"

Jeff Root
2013-Nov-19, 11:53 AM
How do we explain the universe being infinite at the big bang ?
Is that suggesting our big bang took place in a preceding space ?
Or is it suggesting that there was nothing and then the universe
became infinite in an instant. I find it hard to comprehend the
latter as it had a beginning so how could it go on forever.. ?
How do you explain the universe being finite at the big bang?
It would just be the existing state. If you want to travel back
in "time" before the big bang and ask how can something can
go from zero volume to infinite volume then you have to ask
how it could go from zero volume to a finite volume.
The transition seems just as puzzling.
I have made cake go from zero volume to a cubic decimeter
and back to zero volume again.

I have made a pencil line on paper go from zero to five
centimeters long.

I have made a beam of light go from zero to 385,000 km
long, so that it reaches from Earth to the Moon.

Those are three examples of physical things that go from
zero to a finite value. I could name lots more.

Now you name a few examples of physical things that
have gone from zero to infinite value.

-- Jeff, in Minneapolis

Strange
2013-Nov-19, 12:00 PM
I have made cake go from zero volume to a cubic decimeter
and back to zero volume again.

I have made a pencil line on paper go from zero to five
centimeters long.

I have made a beam of light go from zero to 385,000 km
long, so that it reaches from Earth to the Moon.

Those are three examples of physical things that go from
zero to a finite value. I could name lots more.

Now you name a few examples of physical things that
have gone from zero to infinite value.

-- Jeff, in Minneapolis

Does anyone know the name of this logical fallacy?

Jeff Root
2013-Nov-19, 12:04 PM
If you want to travel back in "time" before the big bang
and ask how can something can go from zero volume to
infinite volume ...
There is no need to travel back in time before the Big Bang
to ask this question.

There is no need to imagine going back in time before the
Big Bang to ask this question.

There is no need to imagine that there was such a thing as
time before the Big Bang to ask this question.

Kevin asked the question, and I ask it too, without even
travelling back to a time after the Big Bang: How can
anything go from zero volume to infinite volume?

-- Jeff, in Minneapolis

Jeff Root
2013-Nov-19, 12:07 PM
Does anyone know the name of this logical fallacy?
If you think it has the form of a logical fallacy, please
say exactly why you think so. And if you can put a
name to it yourself, please do.

-- Jeff, in Minneapolis

Jeff Root
2013-Nov-19, 12:29 PM
... the universe might be infinite in size or finite.
If the former then it was always infinite in size ...


... and ask how can something can go from zero volume
to infinite volume ...
Your answer on November 14 was that an infinite
Universe was always infinite. Today your answer is
that the Universe growing to finite volume is just as
inexplicable as it growing to infinite volume.

I really want to see some examples of things that went
from zero to infinite volume, to support your contention
that it is no more surprising than something going from
zero to finite volume, which is a commonplace.

-- Jeff, in Minneapolis

NEOWatcher
2013-Nov-19, 12:38 PM
Those are three examples of physical things that go from
zero to a finite value.
Those are 3 things that were formed from material outside the object.

NoChoice
2013-Nov-19, 12:49 PM
The volume you are talking about, Jeff Root, assumes the prior existence of "space" (whatever that is exactly).

The volume WayneFrancis is talking about is space itself which has come into existence with the BB, or so goes the current lore. Since that is a miraculous event however you look at it, it doesn't seem to make much difference if it was finite space that came from "nothing" or infinite space.

I think it is safe to say that the human mind will never comprehend it because it has no concepts for it. Even if you assume that it was always already there we can't really comprehend it, can we? The human mind "demands" a beginning of some description.

Jeff Root
2013-Nov-19, 12:59 PM
Those are 3 things that were formed from material outside
the object.
Yes. But that fact isn't relevant to Kevin's question.

The question was how something infinite could come from
something which is not infinite. The fact that my examples
are of things made from other things that already existed is
relevant to the question of how anything could come from
nothing, but that isn't the question Kevin asked.

-- Jeff, in Minneapolis

Jeff Root
2013-Nov-19, 01:20 PM
The volume you are talking about, Jeff Root, assumes
the prior existence of "space" (whatever that is exactly).
The volume I was talking about in the examples I gave
assume and depend on the prior existence of space.
I made no such assumption with regard to the Big Bang.



The volume WayneFrancis is talking about is space itself
which has come into existence with the BB, or so goes the
current lore. Since that is a miraculous event however you
look at it, it doesn't seem to make much difference if it
was finite space that came from "nothing" or infinite space.
It makes an enormous difference.

Things go from not existing to existing all the time. When
those things take up volume, they grow from zero volume
to some finite volume. They never become infinite. We
don't know how the Universe got started, but it is easy to
imagine that it began from nothing, and grew. What we
see now that leads us to imagine that event is the actual
expansion of the Universe, apparently a leftover, along
with the CMBR, of the Big Bang. That beginning requires
unknown physics, but it does not require magic, nor does
it require throwing out known physics.

Something going from zero OR FINITE size to infinite size,
on the other hand, is contrary to known physics. What we
observe about how the Universe works tells us that nothing
can grow from finite size to infinite size, and this should
apply to the Universe as a whole as much as it does to any
part of the Universe.

A finite Universe growing from a finite beginning requires
new physics; an infinite Universe growing from a finite
beginning requires magic.

-- Jeff, in Minneapolis

Noclevername
2013-Nov-19, 01:34 PM
We
don't know how the Universe got started, but it is easy to
imagine that it began from nothing, and grew.

Well there's your problem. Imagination is limited, therefore magic? That's not physics, it's metaphysics.


A finite Universe growing from a finite beginning requires
new physics; an infinite Universe growing from a finite
Universe requires magic.

An infinite universe that started out infinite requires no magic, just the a different set of new physics than a finite universe that started out finite and grew larger.

NoChoice
2013-Nov-19, 01:42 PM
Things go from not existing to existing all the time.
Yes. But they don't come from "nothing". The things that come into existence in your case depend on other things that must already exist. It is basically a transformation from one form to another, based on the prior existence of forms. No energy is lost or created.

With regard to the BB it seems we have basically 2 options:

1. There "was nothing" before the BB. In that case the "cause" for the BB is - let's just say - unexplained (and pretty much unexplainable). And in that case (in terms of explanatory power) it doesn't really matter whether a finite universe comes into existence from "nothing" or an infinite one.

2. Something existed before the BB and was always already there - without a beginning. Again, something quite unexplainable with concepts that are accessible to the human mind. And again it doesn't matter whether a finite "something" was there without a beginning or an infinite something. Both are equally amazing.



Something going from zero OR FINITE size to infinite size,
on the other hand, is contrary to known physics. What we
observe about how the Universe works tells us that nothing
can grow from finite size to infinite size, and this should
apply to the Universe as a whole as much as it does to any
part of the Universe.
Indeed. However, those examples are again based on the prior existence of both things and physical laws, which is an entirely different scenario to the "origin of all things".

Strange
2013-Nov-19, 02:00 PM
If you think it has the form of a logical fallacy, please
say exactly why you think so. And if you can put a
name to it yourself, please do.

Well, it is an extension of the argument I have seen elsewhere: "the universe must be finite because you cannot show me an example of something which is infinite". I haven't been able to work out what the generic fallacy is, or even a more general example. It is just obviously wrong.

It may be more of a rhetorical fallacy than a logical one.

Jeff Root
2013-Nov-19, 02:04 PM
An infinite universe that started out infinite requires
no magic,
Yes it does. As I've pointed out numerous times, it
requires that every part of the infinite volume did the
same thing at the same time. A coincidence of truly
supernatural proportions. Physical things don't work
like that. Such an event would require magic.

I have no problem at all with the idea of an infinite
Universe, but if the Universe is infinite, then only a
finite part of it was involved in the Big Bang, because
the Big Bang occurred a finite time ago.

-- Jeff, in Minneapolis

Jeff Root
2013-Nov-19, 02:18 PM
Well, it is an extension of the argument I have seen
elsewhere: "the universe must be finite because you
cannot show me an example of something which is
infinite". I haven't been able to work out what the
generic fallacy is, or even a more general example.
It is just obviously wrong.

It may be more of a rhetorical fallacy than a logical one.
Okay. Perhaps I made it look as though that was my
argument. It wasn't. My actual argument is: Wayne
thinks it is just as puzzling that a finite Universe could
grow from a finite beginning as it is that an infinite
Universe could grow from a finite beginning. I can give
many examples of things that grow to finite size from
a finite beginning, so that is not especially puzzling to
me, and it appears that it isn't especially puzzling to
Kevin, either. If Wayne's view that the two scenarios
are equally puzzling is correct, then he ought to be able
to provide a few examples of infinite things growing
from finite beginnings, just as I provided examples of
finite things growing from finite beginnings.

-- Jeff, in Minneapolis

NEOWatcher
2013-Nov-19, 03:46 PM
Yes. But that fact isn't relevant to Kevin's question.

The question was how something infinite could come from
something which is not infinite.
Fair enough, but.
The cake analogy? I don't understand where "nothing" and "infinite" come into play.
The Pencil analogy? The line is finite because the amount of lead is finite.
The Light analogy? Now we're getting into reference frame issues, but when the light source runs out of energy, the beam stops growing in length. It travels forever, but it's duration is finite.

I'm not disputing what you are arguing because I'm not sure about the details, but I do have an issue with the analogies.

Strange
2013-Nov-19, 03:52 PM
If Wayne's view that the two scenarios
are equally puzzling is correct, then he ought to be able
to provide a few examples of infinite things growing
from finite beginnings, just as I provided examples of
finite things growing from finite beginnings.

And that is the flaw in this argument: what possible examples of infinite objects could he use? (Apart from the fact that showing some examples of hypothesis A does nothing to falsify hypothesis B.)

Jeff Root
2013-Nov-19, 05:23 PM
Fair enough, but.
The cake analogy? I don't understand where "nothing"
and "infinite" come into play.
Wayne said that the Universe going from zero volume to
finite volume is just as puzzling as the Universe going
from zero volume to infinite volume. So I gave three
examples of things that go from zero volume or zero
size to finite size, showing that it is a commonplace
occurrance.

The cake doesn't exist, then I make it, during which
process it achieves a finite size. (Then I eat it, which
makes it stop existing again, since I can't eat my cake
and have it, too.) It is an example of something which
goes from zero volume to finite volume.



The Pencil analogy? The line is finite because the
amount of lead is finite.
It is five centimeters long, as I said. because that's
how long I wanted it to be.



The Light analogy? Now we're getting into reference
frame issues, but when the light source runs out of
energy, the beam stops growing in length. It travels
forever, but it's duration is finite.
I said it is 385,000 km long, so that it reaches from
Earth to the Moon. To make it that length, I turned
the light on for a little over one second. The Moon
being in the way also limited the length.



I'm not disputing what you are arguing because I'm
not sure about the details, but I do have an issue
with the analogies.
They are supposed to be trivial examples of common
things which are seen to come into existence and
acquire a finite size, in analogy to the whole Universe
coming into existence and acquiring finite size. I then
ask Wayne to provide a few similar examples of things
which come into existence and acquire infinite size, to
demonstrate why Kevin and I both find the notion of
the Universe acquiring infinite size considerably more
puzzling than the notion of it acquiring finite size.

-- Jeff, in Minneapolis

Strange
2013-Nov-19, 05:28 PM
I then
ask Wayne to provide a few similar examples of things
which come into existence and acquire infinite size

Using an infinitely large pencil you can draw a line, starting from nothing, which is infinitely long. OK?

Jeff Root
2013-Nov-19, 05:29 PM
And that is the flaw in this argument: what possible
examples of infinite objects could he use?
None. It is an argument by demonstration. I show
that one of the two things he calls equally puzzling
is commonplace, and the other has no examples.
What he can infer from that is that the two things
are not equally puzzling.

-- Jeff, in Minneapolis

NEOWatcher
2013-Nov-19, 05:31 PM
Wayne said that the Universe going from zero volume to
finite volume is just as puzzling as the Universe going
from zero volume to infinite volume. So I gave three
examples of things that go from zero volume or zero
size to finite size, showing that it is a commonplace
occurrance.
Sorry; I got your's and Waynes comments backwards as far as what the end is.

But the beginnings still bother me. I still disagree that your analogies of things that "come into existence", unless you are positing that the universe came from something outside the universe.

Jeff Root
2013-Nov-19, 05:34 PM
Using an infinitely large pencil you can draw a line,
starting from nothing, which is infinitely long. OK?
No, it will never be finished. The line takes forever to
draw, and the Big Bang was just 13.7 billion years ago.

-- Jeff, in Minneapolis

Shaula
2013-Nov-19, 05:41 PM
No, it will never be finished. The line takes forever to
draw, and the Big Bang was just 13.7 billion years ago.

-- Jeff, in Minneapolis
No it was not. Because, and I cannot believe how often I say this to you, there is no Bang in the Big Bang model. It says, as you know, that the observable universe expanded from a hot, dense state a finite time ago. Note: observable. The wider universe is not part of this model because we do not have fundamental enough models to make any firm statements on it.

Strange
2013-Nov-19, 05:47 PM
None. It is an argument by demonstration. I show
that one of the two things he calls equally puzzling
is commonplace, and the other has no examples.

And that is what makes the argument invalid.

(Apart from the fact your examples are bogus. But this is the same old, same old. So I give up. It's not even as if I think the universe came from nothing anyway.)

Jeff Root
2013-Nov-19, 05:54 PM
But the beginnings still bother me. I still disagree
that your analogies of things that "come into existence",
unless you are positing that the universe came from
something outside the universe.
As I said, we can imagine that the Universe came into
existence with the Big Bang. That isn't the only possible
scenario, but it is a popular one. The idea is that nothing
existed, and then something existed, which evolved to
become the present-day Universe. By analogy, my cake
does not exist until I make it. Then it has finite volume.
A line I draw on paper with a pencil does not exist until
I begin to draw it. The line evolves and lengthens as I
pull the pencil across the paper, and it always has finite
length. Nothing deep about thse analogies. They don't
say anything about how the Universe came about. They
just show that something coming into existence is a very
common occurrance when the thing is finite, but rare to
the point of invisibility when it is infinite. So it makes
sense that one is much more puzzling than the other.

-- Jeff, in Minneapolis

NoChoice
2013-Nov-19, 08:58 PM
As I said, we can imagine that the Universe came into
existence with the Big Bang. That isn't the only possible
scenario, but it is a popular one. The idea is that nothing
existed, and then something existed, which evolved to
become the present-day Universe.
Can you really imagine that? I cannot and not for lack of trying.


By analogy, my cake
does not exist until I make it.

That is an entirely inapplicable analogy!
Your cake existed. Just in a different form. In your analogy you simply transform already existing matter and energy.

"Something" coming from "nothing" is a completely different scenario. Incomparably different.

mkline55
2013-Nov-19, 09:16 PM
Start with nothing or zero. Add the number one an infinite number of times.

Noclevername
2013-Nov-19, 09:28 PM
Yes it does. As I've pointed out numerous times, it
requires that every part of the infinite volume did the
same thing at the same time. A coincidence of truly
supernatural proportions. Physical things don't work
like that. Such an event would require magic.

And again and again, it's been explained to you that no coincidence is required, and why, but you just keep on rejecting it because you "can't imagine" it.


I have no problem at all with the idea of an infinite
Universe,

No offense, but you do not act as if you really understand the concept of an infinite universe. You keep on describing the universe in terms appropriate to an expanding object, not all space/time.


but if the Universe is infinite, then only a
finite part of it was involved in the Big Bang, because
the Big Bang occurred a finite time ago.


Aaaaand that's the part that demonstrates your misunderstanding.

The Big "bang" was everywhere at once. It was not actually a bang. It was just the earliest, densest and hottest point that we can model the expanding universe before our mathematical models break down! As the song says, The Whole Universe Was In A Hot Dense State...

caveman1917
2013-Nov-19, 09:50 PM
None. It is an argument by demonstration. I show
that one of the two things he calls equally puzzling
is commonplace, and the other has no examples.
What he can infer from that is that the two things
are not equally puzzling.

Or the availability and number of examples is not correlated with how puzzling the two are. We have many examples of small numbers yet no examples of large numbers (with the distinction between small and large chosen appropriately), does that make large numbers more puzzling? Once you understand addition of small numbers, don't you also understand addition of large numbers? Sure, it may be a bit more work to actually add them, but it is not more puzzling.

KABOOM
2013-Nov-19, 10:01 PM
Isn't it true that infinity is an abstract concept? In other words there nothing in the physical world that can be confirmed to be infinite in size or quantity. We can only come up with "mind exercises" such as start with the number one and add one.... forever. But infinity as a tangible physucal property has never been demonstrated. Hence to me the infinite universe is much akin to the multiverse, bothe are mathmatical concepts that can not be proven.

Noclevername
2013-Nov-19, 10:15 PM
None. It is an argument by demonstration.

It is argument by false analogy.


I show
that one of the two things he calls equally puzzling
is commonplace, and the other has no examples.

Physics is often counter-intuitive, and what is commonplace to the human-scale experience is often inapplicable.


What he can infer from that is that the two things
are not equally puzzling.

"Puzzling" is a relative term. It speaks to the individual's capacity to solve (or create) puzzles. Reality happens the way it happens, regardless of whether it puzzles us or not.

Strange
2013-Nov-19, 10:24 PM
Isn't it true that infinity is an abstract concept?

Is it any more abstract than 0 or 143.79?

We might in future have a theory that implies the universe is infinite (or not). But it won't be "proven" (because that is not how science works, generally).

Strange
2013-Nov-19, 10:25 PM
It is argument by false analogy.
Physics is often counter-intuitive, and what is commonplace to the human-scale experience is often inapplicable.
"Puzzling" is a relative term. It speaks to the individual's capacity to solve (or create) puzzles. Reality happens the way it happens, regardless of whether it puzzles us or not.

Thanks for summarizing that so well. (Better than I could.)

caveman1917
2013-Nov-19, 10:55 PM
A line I draw on paper with a pencil does not exist until
I begin to draw it. The line evolves and lengthens as I
pull the pencil across the paper, and it always has finite
length.

What if the speed at which you are drawing that line equals \sec^2(t), and thus the length of the line at each point in time being \tan(t). Does your line not go from finite size to infinite size in finite time? Yet are you not, at all times, simply drawing a piece of line at a finite speed?

Jeff Root
2013-Nov-19, 11:34 PM
As I've pointed out numerous times, it requires that
every part of the infinite volume did the same thing
at the same time. A coincidence of truly supernatural
proportions. Physical things don't work like that.
Such an event would require magic.
And again and again, it's been explained to you that
no coincidence is required, and why, but you just keep
on rejecting it because you "can't imagine" it.
No, it has been asserted again and again, but it has
not been explained.




I have no problem at all with the idea of an infinite
Universe,
No offense, but you do not act as if you really understand
the concept of an infinite universe. You keep on describing
the universe in terms appropriate to an expanding object,
not all space/time.
I am trying to include the whole range of possibilities.

As I've said before, unless I explicitly say otherwise, I
am always assuming in this thread that the Big Bang was
the origin of all spacetime, and nothing exists that was
not part of the Big Bang. According to known physics,
though, that means a finite Universe. So in a wider
context I don't make any assumption about whether the
Big Bang was the origin of all spacetime or just an event
which marked the beginning of our part of the Universe.
If you insist that we treat the Big Bang as the origin of
all spacetime, then the notion of an infinite Universe is
eliminated.




but if the Universe is infinite, then only a finite part
of it was involved in the Big Bang, because the Big
Bang occurred a finite time ago.
Aaaaand that's the part that demonstrates your
misunderstanding.

The Big "bang" was everywhere at once. It was not
actually a bang.
Can you provide evidence to support this assertion
that the Big Bang was not a bang?



It was just the earliest, densest and hottest point
that we can model the expanding universe before our
mathematical models break down! As the song says,
The Whole Universe Was In A Hot Dense State...
If the mathematical models break down, that means
they are wrong. They wouldn't break down if they
were right.

But general relativity has been found to be highly
accurate in every situation where it has been tested.
Same with quantum mechanics.

-- Jeff, in Minneapolis

Noclevername
2013-Nov-19, 11:49 PM
Can you provide evidence to support this assertion
that the Big Bang was not a bang?


...

Really? You're seriously asking that question? You know that little about BBT and the observations supporting it?

Message sent, not received. All channels, closed.

I give up. :wall: Enough swimming upstream, I'd rather let it drown.

Strange
2013-Nov-19, 11:49 PM
No, it has been asserted again and again, but it has
not been explained.

It has been repeatedly explained. Every time you get on this hobby horse.


According to known physics,
though, that means a finite Universe.

No. According to your assertions, it means a finite universe. The errors in your logic are pointed out every time you bring this up.


Can you provide evidence to support this assertion
that the Big Bang was not a bang?

Maybe you should provide evidence to support your assertion that it was.

korjik
2013-Nov-20, 12:05 AM
If the mathematical models break down, that means
they are wrong. They wouldn't break down if they
were right.

But general relativity has been found to be highly
accurate in every situation where it has been tested.
Same with quantum mechanics.

-- Jeff, in Minneapolis

Snipped by me

Jeff, by definition a mathmatical model breaks down. That is why it is called a mathmatical model. Until we know everything that will be true.

Also, you do realize that when GR and QM are tested against one another they are a little off.

120 orders of magnitude off.

So I think you may need to restate that last bit.

KlausH
2013-Nov-20, 01:07 AM
Also, you do realize that when GR and QM are tested against one another they are a little off.

120 orders of magnitude off.

So I think you may need to restate that last bit.

Seriously? 120 orders of magnitude?
I was aware of discrepancies but I didn't know of the magnitude.

Could you please elaborate on that and/or point me to a link where I can find more information on that?

korjik
2013-Nov-20, 05:29 AM
Seriously? 120 orders of magnitude?
I was aware of discrepancies but I didn't know of the magnitude.

Could you please elaborate on that and/or point me to a link where I can find more information on that?

To be honest, I dont remember what it was. I just remember that number. Not really that important to my point tho, GR and QM at their best are orders of magnitude off when they run into each other.

WayneFrancis
2013-Nov-20, 05:58 AM
I have made cake go from zero volume to a cubic decimeter
and back to zero volume again.

I have made a pencil line on paper go from zero to five
centimeters long.

I have made a beam of light go from zero to 385,000 km
long, so that it reaches from Earth to the Moon.

Those are three examples of physical things that go from
zero to a finite value. I could name lots more.

Now you name a few examples of physical things that
have gone from zero to infinite value.

-- Jeff, in Minneapolis

a photon can be created and go on for ever. Forget the fact that even if I couldn't give an example given your obvious restrictive definition it doesn't mean it isn't valid.
Time could have a start but no end. Since time is a property of our universe and our universe is what we are talking about I would say it would also be classed as physical and also can be infinite but have a starting point.

WayneFrancis
2013-Nov-20, 06:25 AM
Yes. But that fact isn't relevant to Kevin's question.

The question was how something infinite could come from
something which is not infinite. The fact that my examples
are of things made from other things that already existed is
relevant to the question of how anything could come from
nothing, but that isn't the question Kevin asked.

-- Jeff, in Minneapolis

As far as I'm aware the main stream position on the size of the universe (finite or infinite) is "we don't know" meaning we don't have evidence one way or another.
All we can say is that the universe has a lower limit to its size which, again as I understand it, orders of magnitude larger then the observable universe given the standard cosmology.

I have not seen a model that has a finite, closed unbounded universe transition into a open unbounded universe that is supported by the evidence.

My point is the big bang was an initial condition. It may be that it existed in much larger space or bulk. That our visible universe is just a small portion of that larger bulk. That larger bulk may or may not be infinite in size.
That larger bulk may or may not be expanding as our visible universe is.

Regardless the "hot dense" state that was the early universe was not conducive to matter. Ask if the "matter" in our universe "once had no size?" misses the point that before you get to zero volume matter is no longer possible.
Extrapolating back to a point in time, if there was such a concept, where the universe had zero volume, regardless of the question is it infinite or not, is extrapolating back before the big bang where we already don't have the physical laws to describe the initial conditions of the big bang.

I know your philosophical view about how the universe can't be infinite. We've had that discussion before. Most of us admit we can't know if the universe is infinite or finite at this point in time. While you seem to know better then most of the science community out there that admit they don't know. I don't want to beat that dead horse again. My point is that if the universe is infinite in size or not, at the time of the big bang there was NO MATTER. Some type of energy? Yes! A small amount of that energy would get transformed into matter? Yes! But at that point in time there was no matter. I get OCD because people that are not verse in physics get this vision in their head that it is atoms just very squished together which is not true. I have a friend that doesn't believe in the big bang and one of the reasons he uses is it would break the pauli exclusion principle and no matter how much explaining I do he won't let go of the idea of actual atoms clumped together at the time of the big bang.

WayneFrancis
2013-Nov-20, 06:31 AM
The volume I was talking about in the examples I gave
assume and depend on the prior existence of space.
I made no such assumption with regard to the Big Bang.


It makes an enormous difference.

Things go from not existing to existing all the time. When
those things take up volume, they grow from zero volume
to some finite volume. They never become infinite. We
don't know how the Universe got started, but it is easy to
imagine that it began from nothing, and grew. What we
see now that leads us to imagine that event is the actual
expansion of the Universe, apparently a leftover, along
with the CMBR, of the Big Bang. That beginning requires
unknown physics, but it does not require magic, nor does
it require throwing out known physics.

Something going from zero OR FINITE size to infinite size,
on the other hand, is contrary to known physics. What we
observe about how the Universe works tells us that nothing
can grow from finite size to infinite size, and this should
apply to the Universe as a whole as much as it does to any
part of the Universe.

A finite Universe growing from a finite beginning requires
new physics; an infinite Universe growing from a finite
beginning requires magic.

-- Jeff, in Minneapolis

How is this logical fallacy for you Jeff. Show me one physical object that perfectly models the universe.
Just because you don't like the idea of an infinite universe doesn't matter. If you're logic was sound don't you think most cosmologist would hold it instead of being agnostic on the topic?

WayneFrancis
2013-Nov-20, 06:44 AM
Okay. Perhaps I made it look as though that was my
argument. It wasn't. My actual argument is: Wayne
thinks it is just as puzzling that a finite Universe could
grow from a finite beginning as it is that an infinite
Universe could grow from a finite beginning. I can give
many examples of things that grow to finite size from
a finite beginning, so that is not especially puzzling to
me, and it appears that it isn't especially puzzling to
Kevin, either. If Wayne's view that the two scenarios
are equally puzzling is correct, then he ought to be able
to provide a few examples of infinite things growing
from finite beginnings, just as I provided examples of
finite things growing from finite beginnings.

-- Jeff, in Minneapolis

No that isn't what I said. I said it is just as puzzling if the universe had no volume an suddenly had finite volume & energy as it is if it had no volume then suddenly had infinite volume & energy.
I don't know, and happy to be shown, models that posits a finite universe transitioning into a infinite universe but I've yet to see one. If there is one or more models out there like that then my next question is how does the mainstream view these models?

Our disagreement stems from a condition we'll never be able to test where all our physical laws have already broken down so I have no issue saying that in that case an infinite universe could come from "nothing" in a state that is very similar at all parts of that universe. Saying that nothing we know in physics supports this doesn't matter as we would have lost all our physics before that point anyway. Unless you have some grand unified theory that works all the way back "before" the big bang. It is all philosophical at this point because we just don't know and we may never know. It may be impossible to ever know. Not saying we should give up on trying to figure it out...just saying.

WayneFrancis
2013-Nov-20, 06:49 AM
Fair enough, but.
The cake analogy? I don't understand where "nothing" and "infinite" come into play.
The Pencil analogy? The line is finite because the amount of lead is finite.
The Light analogy? Now we're getting into reference frame issues, but when the light source runs out of energy, the beam stops growing in length. It travels forever, but it's duration is finite.

I'm not disputing what you are arguing because I'm not sure about the details, but I do have an issue with the analogies.

And this is the problem with analogies and models. They are only at best approximations and all have their limits. The universe is what it is and what we think it should be doesn't mean a damn thing.
We may find evidence in the future that our universe is part of a larger bulk that is not like our visible universe. I can't even think of a way we could ever prove that it is infinite in size or even what portions outside our visible universe are even like. I have no problem saying that it may be homogeneous and isotropic infinitely. Just has I have no issue saying it might be closed and unbounded. Right now there is no evidence to sway me one way or the other and talking on the matter isn't science as much as it is philosophy.

WayneFrancis
2013-Nov-20, 06:52 AM
Thanks for summarizing that so well. (Better than I could.)

ditto

Shaula
2013-Nov-20, 07:11 AM
No, it has been asserted again and again, but it has
not been explained.
It has been explained as best we can over and over. You just don't like the explanations so they are quietly forgotten or dismissed.

Selfsim
2013-Nov-20, 07:39 AM
... If the mathematical models break down, that means they are wrong. They wouldn't break down if they were right. ...
They are not 'right' and they are not 'wrong'. They are incomplete.

If something was added which made them complete, they would then be inconsistent.

This has been proven.

So far, no one has shown them to be inconsistent.

Van Rijn
2013-Nov-20, 07:40 AM
Well, it is an extension of the argument I have seen elsewhere: "the universe must be finite because you cannot show me an example of something which is infinite". I haven't been able to work out what the generic fallacy is, or even a more general example. It is just obviously wrong.

It may be more of a rhetorical fallacy than a logical one.

I think it would be "appeal to ignorance" - arguing that if something is unproven then it must be false.

Van Rijn
2013-Nov-20, 07:46 AM
It's the same type of argument as "You can't prove that I'm wrong, therefore it must be true."

Noclevername
2013-Nov-20, 07:47 AM
http://en.wikipedia.org/wiki/Argument_from_ignorance

The definition is
It asserts that a proposition is true because it has not yet been proven false (or vice versa). This represents a type of false dichotomy in that it excludes a third option, which is that there is insufficient investigation and therefore insufficient information to prove the proposition satisfactorily to be either true or false.
and
In debates, appeals to ignorance are sometimes used to shift the burden of proof.

Van Rijn
2013-Nov-20, 08:15 AM
This concept (which I don't say is "right" or "wrong") is that the Universe was already infinite, and is still infinite. It's just much less dense now.

(Like having the entire set of integers written down (yes, it's infinite so you couldn't ...) then all the numbers get an extra space between them. You might wonder where all the "extra" paper came from, but it was already infinite. {It hurts my head. My personal "view" is different, but not scientific so I won't raise it.})

Yes, that's an issue where there's a lot of confusion in this type of discussion. Using the word "expansion" makes most people think of something getting larger, but "metric expansion" is NOT about an increase in the size of the universe. It's really just about density. An infinite universe could be like Hilbert's hotel (http://en.wikipedia.org/wiki/Hilbert's_paradox_of_the_Grand_Hotel), where people move to rooms further away from each other, leaving empty rooms and decreasing population density.

And if anyone wants to dismiss that as "just math," I'd point out that many theoretical breakthroughs followed the development of new math. The idea of higher dimensions, for example, used to be thought of as just an interesting bit of math that had little to do with the real world. Science is developed by studying the universe and modeling it, not by insisting on what the universe can or can't do.

Selfsim
2013-Nov-20, 08:23 AM
... And it beats me how ignorance might be present when it comes to models addressing the infinite, when caveman came up with a classic example (http://cosmoquest.org/forum/showthread.php?147215-Infinitesimal-Singularity&p=2171063#post2171063) in direct answer to Jeff's challenge(?)

Noclevername
2013-Nov-20, 08:30 AM
... And it beats me how ignorance might be present when it comes to models addressing the infinite, when caveman came up with a classic example (http://cosmoquest.org/forum/showthread.php?147215-Infinitesimal-Singularity&p=2171063#post2171063) in direct answer to Jeff's challenge(?)

http://en.wikipedia.org/wiki/Antiprocess


Antiprocess is the preemptive recognition and marginalization of undesired information by the interplay of mental defense mechanisms: the subconscious compromises information that would cause cognitive dissonance. It is often used to describe a difficulty encountered when people with sharply contrasting viewpoints are attempting (and failing) to discuss a topic.

In other words, when one is debating with another, there may be a baffling disconnect despite one's apparent understanding of the argument. Despite the apparently sufficient understanding to formulate counter-arguments, the mind of the debater does not allow him to be swayed by that knowledge.

Selfsim
2013-Nov-20, 08:34 AM
http://en.wikipedia.org/wiki/AntiprocessWas that about LiS discussions? :p :)

Noclevername
2013-Nov-20, 08:42 AM
Was that about LiS discussions? :p :)

It does have a familiar ring. A two-sided gong, if I'm not mistaken. ;)

Actually it is more common outside the ATM and CT sections than in them, because those areas have limits on how you can present arguments and for how long, and strictly define where the burden of proof lies.

KlausH
2013-Nov-20, 11:58 AM
Right now there is no evidence to sway me one way or the other and talking on the matter isn't science as much as it is philosophy.

Yes, the lines do get blurry when it comes to questions of "the origin". Just because science as we know it fails at that point doesn't make it any less interesting, not for me anyway.
The question of the origin of the universe has already fascinated me since I was a teenager and has never really left me. I doubt there is an answer and even if there is one we will most likely not be able to understand it. It seems a rather futile exercise and yet I can't help thinking about it at times.

This post summed it up quite well for me:



With regard to the BB it seems we have basically 2 options:

1. There "was nothing" before the BB. In that case the "cause" for the BB is - let's just say - unexplained (and pretty much unexplainable). And in that case (in terms of explanatory power) it doesn't really matter whether a finite universe comes into existence from "nothing" or an infinite one.

2. Something existed before the BB and was always already there - without a beginning. Again, something quite unexplainable with concepts that are accessible to the human mind. And again it doesn't matter whether a finite "something" was there without a beginning or an infinite something. Both are equally amazing.

Shaula
2013-Nov-20, 12:09 PM
A fairly simple third option would be:

3. There is a point in our spacetime that represents the 'moment' when the currently understood causal structure of spacetime was created or became applicable. Before this point it makes no sense to talk about a series of events, or even of a time axis as we understand it because the physical rules that were being obeyed were operating under a different causal set. Until we know how to formulate a physics model that is independent of causal structure and can be transformed between different causal sets we cannot understand this state

KlausH
2013-Nov-20, 12:32 PM
3. There is a point in our spacetime that represents the 'moment' when the currently understood causal structure of spacetime was created or became applicable. Before this point it makes no sense to talk about a series of events, or even of a time axis as we understand it because the physical rules that were being obeyed were operating under a different causal set. Until we know how to formulate a physics model that is independent of causal structure and can be transformed between different causal sets we cannot understand this state

Mmm. Isn't time or a sequence of events the very basis for any concept of causality? The cause causes the effect: this can only be modeled if the sequence is predictable, is it not?

Shaula
2013-Nov-20, 01:03 PM
Mmm. Isn't time or a sequence of events the very basis for any concept of causality? The cause causes the effect: this can only be modeled if the sequence is predictable, is it not?
There is some very interesting, but so far very new, work underway to establish a more general description of what we refer to as causality. Essentially the notion of causality is a shorthand for certain kinds of underlying causal structure, which can in turn be reduced to 'links' in spacetime. I.e. A causes B is actually a series of statements about the positions in spacetime of A and B and the nature of their interaction. What people are trying to do is explore different ways to link up spacetime, different causal structures. By looking at ideas like CDT (http://en.wikipedia.org/wiki/Causal_dynamical_triangulation) causailty can be seen as a property of the behaviour of the simplices used to construct spacetime, this is part of the concept behind Causal Set Theories (http://en.wikipedia.org/wiki/Causal_sets).

So I guess to answer your questions - what is being looked at is what happens when you change the members of a causal set. There are still deterministic rules and predictions, it is just not easy to express them in terms of what we would regard as sequences of events, causality.

Edit: To add, these are very speculative ideas being investigated. They are very early phase concepts. They may be totally wrong, but the interesting thing is that in proving that we may find some insights into what causality is.

Jeff Root
2013-Nov-20, 04:44 PM
It is an argument by demonstration. I show that
one of the two things he calls equally puzzling
is commonplace, and the other has no examples.
What he can infer from that is that the two things
are not equally puzzling.
Or the availability and number of examples is not
correlated with how puzzling the two are.
In this case it is. Familiarity with something common
and unfamiliarity with something that has never been
observed is the result. It is what the examples and
lack of examples demonstrate.



We have many examples of small numbers yet no
examples of large numbers (with the distinction between
small and large chosen appropriately), does that make
large numbers more puzzling?
Certainly. You participated a few days ago in an old
thread on this subject:

http://cosmoquest.org/forum/showthread.php?144291-Comprehending-numbers

Opinion there suggested that numbers greater than
four are not immediately comprehended by humans
because there was no evolutionary advantage to it,
and numbers in the thousands may not really be
comprehensible by humans at all.



Once you understand addition of small numbers, don't
you also understand addition of large numbers? Sure,
it may be a bit more work to actually add them, but it
is not more puzzling.
Understanding how to add is not the same as making
a "large" number familiar.

Kevin stated that he finds it hard to comprehend the
Universe becoming infinite in an instant.

Wayne replied, claiming that a transition from zero
volume to finite volume seems just as puzzling as a
transition from zero volume to infinite volume.

I then replied to Wayne, citing three examples of things
which go from zero size to finite size, and challenged
him to give examples of things which go from zero size
to infinite size. I showed that a transition from zero
volume to finite volume, like my cake, is very familiar
to everyone, while a transition from zero volume to
infinite volume has never been seen by anyone, ever.

I can't force anyone to agree with me that something
which has never been seen by anyone is very likely to
be more puzzling than something which is seen by
nearly everyone nearly every day, but it surprises me
and alarms me that you would argue against it.

-- Jeff, in Minneapolis

Jeff Root
2013-Nov-20, 04:47 PM
It is an argument by demonstration.
It is argument by false analogy.
I think you are wrong. Analogy is involved, and all
analogies are faulty, but the analogies are not the
argument in this case, and I believe the analogies
are not faulty in any way that makes them "false".

I presented three examples of things which go from
nonexistence to finite size: Cake that I have made,
a pencil line I have drawn, and a beam of light that
I sent to the Moon. I could present any number of
other examples.

These examples show that the transition of some
physical thing from nonexistence to finite size is
familiar to everyone.

The fact that they are analogues to a scenario of
how the Universe may have begun is not part of my
argument. They do not need to be considered as
analogous to anything, but they still show that a
transition from nonexistence to finite size is familiar
to everyone.

If you must examine the analogy aspect of the
examples, of course it is true that the substance and
energy of the cake, the line, and the light beam, and
their creation, all existed before they were created,
which is unlikely to be analogous to what happened
with the beginning of the Universe. So what? That
flaw in the analogy is completely irrelevant to the
point that a transition from zero volume to infinite
volume would be more puzzling than a transition
from zero volume to finite volume.

The flaw in the analogy is not fatal. The flaw in the
analogy doesn't even weaken the argument slightly,
because the analogy is not part of the argument.





I show that one of the two things he calls equally
puzzling is commonplace, and the other has no
examples.
Physics is often counter-intuitive, and what is
commonplace to the human-scale experience is
often inapplicable.
This is a valid criticism of the larger argument that
an infinite Universe could not result from a finite
event. The fact that the notion puzzles Kevin and
myself is not an argument that it is impossible or
unlikely. But human intuition is extremely powerful.
While it often gives wrong results, it very often
gives useful results. It is as big an error to dismiss
intuition as false as to embrace it as true.

How an infinite Universe could result from a finite
beginning is certainly puzzling. That puzzle is usually
responded to here on BAUT / CQ with the assertion
that if the Universe is infinite, it was infinite from the
beginning. Which raises the puzzle of how the Big
Bang could occur simultaneously throughout infinite
volume. It is usually responded to with the assertion
that everything participating in the Big Bang started
out in causal contact at the singularity. Which raises
the puzzle of how an infinite volume could be in
causal contact. Though you personally have instead
been asserting that it may just have been natural for
that to happen -- it's what spacetime necessarily does.
Which raises the puzzle of why spacetime necessarily
does that.

Being puzzled is generally a good sign.

-- Jeff, in Minneapolis

Jeff Root
2013-Nov-20, 04:50 PM
A line I draw on paper with a pencil does not exist until
I begin to draw it. The line evolves and lengthens as I
pull the pencil across the paper, and it always has finite
length.
What if the speed at which you are drawing that line
equals \sec^2(t), and thus the length of the
line at each point in time being \tan(t).
It took a few minutes for me to figure out that "sec"
must mean "secant". I can't visualize what you are
trying to describe here.



Does your line not go from finite size to infinite size in
finite time?
The line I drew was about 5 cm long. It took me roughly
a second to draw it. I don't know about the line you are
describing. If it is infinitely long, then it is a mathematical
concept, not a pencil line. I'll assume it is infinitely long.



Yet are you not, at all times, simply drawing a piece of
line at a finite speed?
If the line goes from finite size to infinite size in finite
time, then it very definitely is not drawn at finite speed.

However none of that is relevant. I asked Wayne for
"a few examples of physical things that have gone from
zero to infinite value." Your line is not a physical thing,
and it is not something that has ever been done or ever
will be done.

-- Jeff, in Minneapolis

Strange
2013-Nov-20, 06:08 PM
Opinion there suggested that numbers greater than
four are not immediately comprehended by humans
because there was no evolutionary advantage to it,
and numbers in the thousands may not really be
comprehensible by humans at all.

Is that an admission that your aversion to an infinite universe is purely subjective after all?


Understanding how to add is not the same as making
a "large" number familiar.

And having a scientific theory that involves an infinite universe as not the same as making the idea familiar.

It would be nice if you realised and/or admitted that this is just a personal preference/belief/prejudice and that all your analogies and "logic" are just an attempt to satisfy your emotional need.

Strange
2013-Nov-20, 06:10 PM
However none of that is relevant. I asked Wayne for
"a few examples of physical things that have gone from
zero to infinite value." Your line is not a physical thing,
and it is not something that has ever been done or ever
will be done.

So your argument comes down to, "show me something impossible and I will believe you."

pzkpfw
2013-Nov-20, 06:24 PM
... Which raises the puzzle of how the Big
Bang could occur simultaneously throughout infinite
volume. ...

We don't know much about the Universe beyond our own visible bit of it, so any puzzle based on what the "whole" Universe did * or didn't do seems a bit off.

i.e. You can't assert that the whole Universe "Big-Banged" at the same time, then call that a puzzle.


Edit: * to be clear, I get 'the "whole" Universe' from your 'throughout infinite volume'.

Selfsim
2013-Nov-20, 08:46 PM
... If it is infinitely long, then it is a mathematical concept, not a pencil line.

If the line goes from finite size to infinite size in finite time, then it very definitely is not drawn at finite speed.
However none of that is relevant. But the descriptions applied to the BB, which led to this issue of finite origins leading to infinite expanse, all originate in mathematical descriptions/concepts. The concept of 'infinity' is a mathematical concept .. line-drawing pencils are not.

Perhaps what you're saying is that a finite origin leading to an infinite expanse, does not translate from the pure maths domain/description into the physical domain, unless purely empirical evidence can be produced(?) That is a reasonable point, but saying that the math models are 'wrong' because they 'break down', (in a physical sense), is not a valid comparison either because the so-called 'break down' itself, is not supported with empirical evidence from the physical domain.

Jeff Root
2013-Nov-21, 08:48 AM
korjik,

I started composing a reply to a post of yours back on
the first page of this thread, but didn't complete it so
I haven't posted it yet. I still intend to.




If the mathematical models break down, that means
they are wrong. They wouldn't break down if they
were right.

But general relativity has been found to be highly
accurate in every situation where it has been tested.
Same with quantum mechanics.
Jeff, by definition a mathmatical model breaks down.
That is why it is called a mathmatical model.
Really? So, if something that otherwise appears to be
a mathematical model doesn't break down, it should not
be called a mathematical model?

Or is a "mathmatical model" something different from a
mathematical model?

I agree with Selfsim on this: No model is complete, and
being incomplete is not the same as being broken.



Also, you do realize that when GR and QM are tested
against one another they are a little off.
I am very aware that they conflict in certain areas.
I had that in mind as I wrote the above.



120 orders of magnitude off.

So I think you may need to restate that last bit.
I was quite uncomfortable writing that. When I said
essentially the same thing earlier in the thread, I didn't
at that time go so far as to claim that QM tests as
perfectly as GR does. I knew I was probably forgetting
something. The 120 orders of magnitude difference
between the "vacuum energy" predicted by QM and that
inferred from what is observed is certainly a big problem
that needs resolution. I didn't think of it because the
nature of "vacuum energy" is so complex, and so much
in dispute, that it isn't at all clear what the significance
of the anomaly might be. It appears to be a completely
unique situation. QM may have many other problems
(of lesser magnitude!), but I'm not aware of any. At the
moment, I would say that aside from this one really big
question about the vacuum energy anomaly, QM has
been found to be highly accurate in every situation
where it has been tested.

-- Jeff, in Minneapolis

korjik
2013-Nov-21, 02:37 PM
If you model dosent break, you either know everything or havent reached the limit of the model. All models have a limit because what you know has a limit.

caveman1917
2013-Nov-21, 10:43 PM
The line I drew was about 5 cm long. It took me roughly
a second to draw it.

Good, do you think you can do that a second time, drawing that line of 5 cm but add a 1 cm bit a bit faster than you added the first 5 cm? Do you think you can do that continuously, keeping to draw the line but going increasingly faster, yet at finite speed, as you're drawing it? Then depending on how you accelerated you have just drawn an infinite line in finite time.

Jeff Root
2013-Nov-21, 11:01 PM
The Big "bang" was everywhere at once. It was not
actually a bang.



Can you provide evidence to support this assertion
that the Big Bang was not a bang?
Really? You're seriously asking that question?
Of course. That's a mighty strange assertion, there.
The Big Bang was certainly the biggest bang ever.
As you said, it was everywhere at once.



You know that little about BBT and the observations
supporting it?
You know very well that I know about as much about the
Big Bang as you do. Saying it was not actually a bang
looks like a non sequitur. It doesn't follow from anything
else you said, it is very surprising, and it isn't supported
by evidence. Maybe it was just a flip comment that you
didn't think anyone would take literally. Is that it?

-- Jeff, in Minneapolis

Jeff Root
2013-Nov-21, 11:02 PM
Seriously? 120 orders of magnitude?
I was aware of discrepancies but I didn't know of the magnitude.

Could you please elaborate on that and/or point me to a link
where I can find more information on that?
To be honest, I dont remember what it was. I just remember
that number. Not really that important to my point tho, GR and
QM at their best are orders of magnitude off when they run
into each other.
Various different interpretations of how to calculate something
called "vacuum energy" in quantum mechanics give results that
are vastly greater than reasonable interpretations of what is
observed permit. The most widely-accepted method of deriving
the value in QM gives a figure some 120 orders of magnitude
larger than what it actually appears to be. So far there is no
adequate explanation for this enormous discrepency. It is a
major puzzle.

Aside from that one item, though, general relativity and
quantum mechanics get along well except in the most extreme
conditions, such as deep in the interior of a black hole and
the first tiny fraction of a second after the singularity of the
Big Bang. The fact that they disagree there means we don't
know what the conditions there actually are. New physics is
required to explain what is going on in those cases.

-- Jeff, in Minneapolis

Jeff Root
2013-Nov-21, 11:06 PM
I have made cake go from zero volume to a cubic decimeter
and back to zero volume again.

I have made a pencil line on paper go from zero to five
centimeters long.

I have made a beam of light go from zero to 385,000 km
long, so that it reaches from Earth to the Moon.

Those are three examples of physical things that go from
zero to a finite value. I could name lots more.

Now you name a few examples of physical things that
have gone from zero to infinite value.
a photon can be created and go on for ever.
Possibly, but it certainly hasn't happened yet. You told
Kevin that the Universe going from zero volume to finite
volume is just as puzzling as the Universe going from
zero volume to infinite volume. So I gave three examples
of things that are observed to actually go from zero
volume or zero size to finite size, showing that it is a
commonplace occurrance, and should therefore be
familiar to Kevin, to you, and to just about everyone.

A photon going on forever is not something that has ever
been observed, nor will it ever be observed. So it does
not support your contention that the Universe going from
zero volume to finite volume is just as puzzling as the
Universe going from zero volume to infinite volume.



Forget the fact that even if I couldn't give an example given
your obvious restrictive definition it doesn't mean it isn't valid.
The point is that there is something puzzliing about anything
going from zero volume to infinite volume -- an occurrance
never observed by anyone -- that is not puzzling about
something going from zero volume to finite volume -- an
occurrance that almost everyone observes daily.



Time could have a start but no end.
Certainly. It's a possibility I've been aware of for decades.



Since time is a property of our universe and our universe is
what we are talking about I would say it would also be classed
as physical and also can be infinite but have a starting point.
Yes, but nobody has observed this, so it doesn't support
your claim that the two scenarios are equally puzzling.

-- Jeff, in Minneapolis

Jeff Root
2013-Nov-21, 11:09 PM
Yes. But that fact isn't relevant to Kevin's question.

The question was how something infinite could come from
something which is not infinite. The fact that my examples
are of things made from other things that already existed is
relevant to the question of how anything could come from
nothing, but that isn't the question Kevin asked.
As far as I'm aware the main stream position on the size of the
universe (finite or infinite) is "we don't know" meaning we don't
have evidence one way or another.

All we can say is that the universe has a lower limit to its size
which, again as I understand it, orders of magnitude larger
then the observable universe given the standard cosmology.
I agree completely.



I have not seen a model that has a finite, closed unbounded
universe transition into a open unbounded universe that is
supported by the evidence.

My point is the big bang was an initial condition. It may be that
it existed in much larger space or bulk. That our visible universe
is just a small portion of that larger bulk. That larger bulk may or
may not be infinite in size.

That larger bulk may or may not be expanding as our visible
universe is.

Regardless the "hot dense" state that was the early universe was
not conducive to matter. Ask if the "matter" in our universe "once
had no size?" misses the point that before you get to zero volume
matter is no longer possible.

Extrapolating back to a point in time, if there was such a concept,
where the universe had zero volume, regardless of the question
is it infinite or not, is extrapolating back before the big bang
where we already don't have the physical laws to describe the
initial conditions of the big bang.

I know your philosophical view about how the universe can't be
infinite. We've had that discussion before. Most of us admit we
can't know if the universe is infinite or finite at this point in time.
While you seem to know better then most of the science
community out there that admit they don't know. I don't want to
beat that dead horse again.
I have never in my life expressed or held a view that the
Universe can't be infinite. I *have* said (elsewhere) that an
infinite Universe is unfathomable, but at the same time I also
said that a finite Universe is equally unfathomable.

What I have said here is that if the Universe is infinite, then
only a finite part of it was involved in the Big Bang, and if the
entire Universe was involved in the Big Bang, then the Universe
is finite. I have no idea whether it is finite or infinite.

-- Jeff, in Minneapolis

Jeff Root
2013-Nov-21, 11:11 PM
Wayne thinks it is just as puzzling that a finite Universe
could grow from a finite beginning as it is that an infinite
Universe could grow from a finite beginning. I can give
many examples of things that grow to finite size from
a finite beginning, so that is not especially puzzling to
me, and it appears that it isn't especially puzzling to
Kevin, either. If Wayne's view that the two scenarios
are equally puzzling is correct, then he ought to be able
to provide a few examples of infinite things growing
from finite beginnings, just as I provided examples of
finite things growing from finite beginnings.
No that isn't what I said. I said it is just as puzzling if the
universe had no volume an suddenly had finite volume
& energy as it is if it had no volume then suddenly had
infinite volume & energy.
You did not say anything about it being sudden:



If you want to travel back in "time" before the big bang and
ask how can something can go from zero volume to infinite
volume then you have to ask how it could go from zero volume
to a finite volume. The transition seems just as puzzling.
I accurately described what you said.

Whether it was sudden or not doesn't matter anyhow.
Either way, a transition from zero or finite size to infinite
size is something which has never been observed, while
a transition from zero or finite size to finite size is a
commonplace, contradicting your claim that the two are
equally puzzling.



I don't know, and happy to be shown, models that posits a
finite universe transitioning into a infinite universe but I've
yet to see one.
Well, there you go! I'd like to see one of those, too, but I
suspect there aren't any, because they wouldn't work.

-- Jeff, in Minneapolis

Selfsim
2013-Nov-22, 12:13 AM
Good, do you think you can do that a second time, drawing that line of 5 cm but add a 1 cm bit a bit faster than you added the first 5 cm? Do you think you can do that continuously, keeping to draw the line but going increasingly faster, yet at finite speed, as you're drawing it? Then depending on how you accelerated you have just drawn an infinite line in finite time.On pondering the sec^2 example, (not sure if you're intending the above to be a continuance of the same line of argument or not(?)), it seems that whatever time interval is used for the velocity, also applies for the distance. The distance, or line length, tan(t)+c, remains finite only if one excludes the asymptote intervals.

The asymptote t=pi/2+n*pi (n=0,1,2,3 …), is also an asymptote for the distance, tan(t)+c, as well. t is discontinuous at the above values, hence we can only look at t in intervals such as 0<=t<pi/2, pi/2<t<3pi/2, etc.

(Tan(t)+c can also approach minus infinity as well as plus infinity).

Assuming the velocity is finite, automatically excludes the behaviour of the function at these asymptotes .. this also applies to the distance function at the same asymptotes .. hence if the velocity is finite, this then implies that the distance is also finite(?)

Noclevername
2013-Nov-22, 12:30 AM
Of course. That's a mighty strange assertion, there.
The Big Bang was certainly the biggest bang ever.
As you said, it was everywhere at once.


No, no, no, no, no, no.

A "bang" is an expansion of matter and energy into space. The BB is an expansion of space itself.


You know very well that I know about as much about the
Big Bang as you do.

If that were true then why don't you get it when I say it was not a literal bang?

caveman1917
2013-Nov-22, 12:46 AM
Assuming the velocity is finite, automatically excludes the behaviour of the function at these asymptotes .. this also applies to the distance function at the same asymptotes .. hence if the velocity is finite, this then implies that the distance is also finite(?)

These functions do not have any behaviour at these asymptotes because they do not exist there, but even if they did, the limit of a function at a point does not depend on the function value at that point.

Yes, the velocity goes to infinity in finite time too.

Noclevername
2013-Nov-22, 12:53 AM
JeffRoot, let me TRY to explain it one last time.

A "bang" or explosion is a localized release of energy that causes a local spike in material pressure, which is then transferred out into its environment through existing space from a central locus. It is a conversion and transfer of energy over physical locations.

The Big Bang was an expansion of all space that caused a universal drop in pressure.

The two are not the same in any way.

You still appear, by your descriptions of the BB, to be interpreting T=0 and after as a physical explosion. This is not an accurate model.

You keep saying that you are not doing this, that you understand mainstream BB theory, but your responses and assertions say otherwise. Take some time to look at your own posts and read them as if reading someone else's work. Do more research and try to think about why we keep telling you the same things over and over.

If you still don't get the difference, then I guess there's no point in continuing.

WayneFrancis
2013-Nov-22, 02:37 AM
korjik,

...

Or is a "mathmatical model" something different from a
mathematical model?

I agree with Selfsim on this: No model is complete, and
being incomplete is not the same as being broken.

...
-- Jeff, in Minneapolis

Now you are just obfuscating the real issue with grammar nazi tactics and then using semantics which may work with some of the more casual readers.
Incomplete and broken can mean the same thing.
Incomplete is easy. Just by being a model, as you say, it isn't complete.
Being incomplete means it isn't fully functional. Let us look at a definition of broken.


bro·ken (brkn)
v.
Past participle of break.
adj.
1. Forcibly separated into two or more pieces; fractured: a broken arm; broken glass.
2. Sundered by divorce, separation, or desertion of a parent or parents: children from broken homes; a broken marriage.
3. Having been violated: a broken promise.
4.

a. Incomplete: a broken set of books.
b. Being in a state of disarray; disordered: troops fleeing in broken ranks.
5.

a. Intermittently stopping and starting; discontinuous: a broken cable transmission.
b. Varying abruptly, as in pitch: broken sobs.
c. Spoken with gaps and errors: broken English.
6. Topographically rough; uneven: broken terrain.
7.

a. Subdued totally; humbled: a broken spirit.
b. Weakened and infirm: broken health.
8. Crushed by grief: died of a broken heart.
9. Financially ruined; bankrupt.
10. Not functioning; out of order: a broken washing machine.

Oh look at that ... Incomplete. Hmmm
there I go ... I'm beating a dead horse against my own wishes.

WayneFrancis
2013-Nov-22, 02:41 AM
If you model dosent break, you either know everything or havent reached the limit of the model. All models have a limit because what you know has a limit.

I go one set further and say if your model doesn't break then you don't have a model. You have the actual thing. Say I could make a model of a human that does everything a human does then is that a model? I say no...it would be a human.

WayneFrancis
2013-Nov-22, 03:03 AM
Possibly, but it certainly hasn't happened yet.

So here come the caviats. So you are asking for something that is impossible according to your definition. Forget the fact that a photon can exist for infinity because we know of no physical laws where a photon will, by itself, just poof out of existence. But since the universe hasn't been around for an infinite amount of time yet, an impossible condition now set by you, then everything is now invalidated. Do you honestly think you are that clever that no one will see you are putting impossible constraints on this topic just to weed out thing that prove your statement wrong?



You told Kevin that the Universe going from zero volume to finite
volume is just as puzzling as the Universe going from
zero volume to infinite volume. So I gave three examples
of things that are observed to actually go from zero
volume or zero size to finite size, showing that it is a
commonplace occurrance, and should therefore be
familiar to Kevin, to you, and to just about everyone.


and you missed the most important part of my comment "THE UNIVERSE"
none of those things you talk about have the properties of the universe. The universe popping into existence is puzzling, unless you
want to step up and claim your Nobel Prize for discovering the origins of the universe. The 3 things you listed we understand where
they came from so there is no puzzle. The origins of the universe is very different but you don't seem to care about facts like that.



A photon going on forever is not something that has ever
been observed, nor will it ever be observed. So it does
not support your contention that the Universe going from
zero volume to finite volume is just as puzzling as the
Universe going from zero volume to infinite volume.


So now you want something that can only be observed and since you can't ever observe something infinite in its entirety, by definition, all things that might be infinite would be disqualified for you.



The point is that there is something puzzliing about anything
going from zero volume to infinite volume -- an occurrance
never observed by anyone -- that is not puzzling about
something going from zero volume to finite volume -- an
occurrance that almost everyone observes daily.


No the point is you are using intellectually disingenuous tactics most often employed by cranks like those that deny evolution. This speaks volumes.



Certainly. It's a possibility I've been aware of for decades.

Yes, but nobody has observed this, so it doesn't support
your claim that the two scenarios are equally puzzling.

-- Jeff, in Minneapolis

You might as well say "The dinosaurs didn't live millions of years ago because you were not there to observe it"
You arguments are getting worse with every post. Have you been studying tactics from Ken Ham?

grapes
2013-Nov-22, 03:10 AM
Either way, a transition from zero or finite size to infinite
size is something which has never been observed, while
a transition from zero or finite size to finite size is a
commonplace, contradicting your claim that the two are
equally puzzling.Just out of curiosity, what have we observed that goes from zero to finite size?

WayneFrancis
2013-Nov-22, 03:13 AM
Just out of curiosity, what have we observed that goes from zero to finite size?

Didn't you see his 3 examples! A pencil line for one. Because that is a great analogy for something like the universe! :wall:

WayneFrancis
2013-Nov-22, 03:22 AM
You did not say anything about it being sudden:



Care to explain how the universe going from zero volume to infinite volume could be anything but sudden?



I accurately described what you said.


No you are not you are twisting what I say, creating a straw man, distorting the meanings so your position seems, at first glance, more valid.



Whether it was sudden or not doesn't matter anyhow.
Either way, a transition from zero or finite size to infinite
size is something which has never been observed, while
a transition from zero or finite size to finite size is a
commonplace, contradicting your claim that the two are
equally puzzling.


So first you complain about me using the term "sudden" then you say it doesn't matter. Take out the word for all I care. It doesn't change the fact that the beginning of the universe is puzzling.
This is also where you are being no better then a creationist denying evolution. Because the beginning of the universe can never be observed you can dismiss anyone's explanation that you don't like but you don't apply the same logic to your view.



Well, there you go! I'd like to see one of those, too, but I
suspect there aren't any, because they wouldn't work.

-- Jeff, in Minneapolis

Argument from ignorance. Notice I've said to someone else saying there are models that have that transition that I'd like to see them. You just outright say they "wouldn't work" without seeing the explanation.
Very telling how you repeatedly show how, no matter what, you will not accept anything that goes against the way you have things pictured in your mind.

Selfsim
2013-Nov-22, 03:26 AM
These functions do not have any behaviour at these asymptotes because they do not exist there, but even if they did, the limit of a function at a point does not depend on the function value at that point.Surely the behaviour of a function as it approaches a limit has a distinct meaning from its value at the limit?

Yes, the velocity goes to infinity in finite time too.Err, following the logic I laid out in my prior post, leads to a conclusion of: finite velocity implies finite distance over the same time frame ..

If, on the other hand, (as you say), the velocity asymptotes to infinity and the function cannot be said to have any specific behaviour at such an asymptote, then by the same logic, I don't see how this can then be said to imply that this happens in a finite time. (Ie: if the function no longer exists there anymore(?) ) ..

Jeff Root
2013-Nov-22, 01:19 PM
Either way, a transition from zero or finite size to infinite
size is something which has never been observed, while
a transition from zero or finite size to finite size is a
commonplace, contradicting your claim that the two are
equally puzzling.
Just out of curiosity, what have we observed that
goes from zero to finite size?
As Wayne said, I gave three examples in the post
where I first raised this objection:



I have made cake go from zero volume to a cubic decimeter
and back to zero volume again.

I have made a pencil line on paper go from zero to five
centimeters long.

I have made a beam of light go from zero to 385,000 km
long, so that it reaches from Earth to the Moon.

Those are three examples of physical things that go from
zero to a finite value. I could name lots more.

Now you name a few examples of physical things that
have gone from zero to infinite value.
If the first example isn't obvious, I made the cake, then
ate it. The eating part isn't relevant, but I couldn't resist
the implied reference to not being able to eat my cake
and have it, too.

In making the cake, obviously I used ingredients and
energy which already existed. That fact is completely
irrelevant to my point.

Maybe I can make my point clear by being more explicit:
There are many ways in which the Big Bang and theories
about the Big Bang are puzzling. Kevin pointed out one.
He said he finds it hard to comprehend that "there was
nothing and then the universe became infinite in an
instant." But there are actually at least two separate
puzzles there: How the Universe could go from nothing
to something is one puzzle, and how the Universe could
become infinite is a second puzzle. Kevin clearly was
talking about the puzzle of the Universe becoming
infinite, not the puzzle of how it could go from nothing
to something. It is what I have been talking about.
Yet the majority of arguments against me have been
fixated on the puzzle of the Universe going from nothing
to something, which is irrelevant to what I'm saying.

What I'm saying is that the idea of the Universe
becoming infinite is puzzling in a way that the idea of
the Universe going from nothing to something is not.

Both ideas are puzzling, but the puzzle of how the
Universe could become infinite is on top of the puzzle
that all theories of the origin of the Universe have to
address. We have innumerable examples of things
going from nothing to something, but no example of
anything becoming infinite. So the idea of the Universe
becoming infinite is doubly puzzling -- more puzzling
than the idea of the Universe becoming finite.

This seems terribly obvious. I don't know why I have
to argue it at such absurd length.

-- Jeff, in Minneapolis

.

Jeff Root
2013-Nov-22, 01:42 PM
Noclevername,

I'll reply regarding your notion of whether the Big Bang
was a bang or not in another thread. I'm waiting for info
from an interlibrary loan. Meanwhile...



I give up. :wall: Enough swimming upstream, I'd rather
let it drown.
Is that yellow character you? What is he doing?

-- Jeff, in Minneapolis

Strange
2013-Nov-22, 02:14 PM
We have innumerable examples of things
going from nothing to something, but no example of
anything becoming infinite.

How is that relevant to anything?

And, of course, we might have one example... (not that I think we do)
There doesn't have to be another to make it true.

We only have one example of a egg-laying, duck-billed, beaver-tailed, otter-footed, venomous mammalian species. That doesn't mean it doesn't exist.

Jeff Root
2013-Nov-22, 02:59 PM
If the mathematical models break down, that means they
are wrong. They wouldn't break down if they were right.
They are not 'right' and they are not 'wrong'. They are
incomplete.
A model *can* be wrong, of course, but a model may
fail to give a correct prediction not because it is wrong
but because it is incomplete.

I can model the acceleration of an object falling due to
gravity near Earth's surface as a=9.8 m/s2 .
My model says that when I drop an object from a height
of 240 m, it should reach the ground in seven seconds.
Yet the ping pong ball I drop takes far longer than that
to reach the ground.

Is my model of Earth's gravity wrong? No, it is just
incomplete, failing to take drag into account.

Is my model broken? It is broken if you expect it to take
drag into account, but it is not broken if you do not expect
it to take drag into account.

GR predicts a singularity at T=0. QM says there can be
no such thing. Does that mean one of them is broken?
I don't expect GR to take quantum effects into account,
and I don't expect QM to take relativistic effects into
account.

I can, with considerable effort in measuring drag, add a
term to my equation for gravitational acceleration to make
it a better model for falling ping pong balls. Combining
GR and QM is far more difficult, and hasn't yet been done,
so I don't expect the standard model of cosmology to be
able to predict what happened near T=0. I don't consider
the model to be broken. I don't consider GR to be broken.
I don't consider QM to be broken. They are not wrong.
They are incomplete.



If something was added which made them complete, they
would then be inconsistent.

This has been proven.

So far, no one has shown them to be inconsistent.
I'm sure you know that GR and QM are inconsistent with
each other near the predicted singularity of the Big Bang
as well as near the predicted singularity of a black hole.
I suspect that something can be added to relieve the
inconsistency. That wouldn't make the models complete
in an absolute sense. It would just make them more
nearly complete than they are now.

-- Jeff, in Minneapolis

caveman1917
2013-Nov-22, 03:20 PM
Surely the behaviour of a function as it approaches a limit has a distinct meaning from its value at the limit?

Err, following the logic I laid out in my prior post, leads to a conclusion of: finite velocity implies finite distance over the same time frame ..

If, on the other hand, (as you say), the velocity asymptotes to infinity and the function cannot be said to have any specific behaviour at such an asymptote, then by the same logic, I don't see how this can then be said to imply that this happens in a finite time. (Ie: if the function no longer exists there anymore(?) ) ..

What you seem to be missing is that infinity is not a number, at least not in the real number system. A function cannot have the value "infinity", and that is not what it means for the universe to be infinite, that the "size function" would have the value "infinity". What it means for a universe to be infinite is that no matter which two points you choose there will always be two other points that are even further apart. Or in the case of a function, infinity is defined as the limit of a function that diverges. It doesn't matter what the function value is at the limit, what matters is what the function does before getting to the limit point. If a function diverges in finite time that means, considering that function to denote the radius of curvature of the universe, that in finite time the statement "i can choose two points such that there are no other two points that are further apart" becomes false - meaning that universe goes to infinite size in finite time. Nothing needs to have the value "infinity" here, nothing even can since that is not a value in the real number system.

But even if you were to use extensions to the real number system that do include infinity and hence do reach the value "infinity" at that point, then it would still be irrelevant what the velocity is at that point. Velocity is the rate of change of position, and the velocity at some point has no influence over the position at that point, because position is thus the time-integral of velocity and an integral over a measure-zero set is always zero, independently of the value of the function over that set (even if that value is infinite).

The only aspect that decides whether the function goes to infinity in finite time is what the function does before reaching the limit point, and over that domain everything is finite. Rather than thinking of it as the function reaching infinity, think of it as whether the function diverges.

Jeff Root
2013-Nov-22, 03:27 PM
We have innumerable examples of things going from
nothing to something, but no example of anything
becoming infinite.
How is that relevant to anything?
As I've said way too many times, it shows why the
idea of the Universe going from zero volume to infinite
volume is more puzzling than the idea of the Universe
going from zero volume to finite volume. One case
involves one puzzle, while the other case involves two
puzzles. This is only relevant to the fact that Wayne
said to Kevin that the two cases are equally puzzling.
That clearly is not true.



And, of course, we might have one example...
(not that I think we do)
There doesn't have to be another to make it true.
I never suggested anything like that.



We only have one example of a egg-laying, duck-billed,
beaver-tailed, otter-footed, venomous mammalian species.
That doesn't mean it doesn't exist.
On the contrary, we have one example of an egg-laying,
duck-billed, beaver-tailed, otter-footed, venomous
mammalian species. That means it exists.

What if we didn't have an example of an egg-laying,
duck-billed, beaver-tailed, otter-footed, venomous
mammalian species? What would we expect?

What if we didn't have an example of something physical
that goes from zero size to infinite size? Would we find
the idea puzzling? More puzzling than something physical
that goes from zero size to finite size?

-- Jeff, in Minneapolis

Strange
2013-Nov-22, 03:31 PM
As I've said way too many times, it shows why the
idea of the Universe going from zero volume to infinite
volume is more puzzling than the idea of the Universe
going from zero volume to finite volume.

I apologise. I thought you were using the lack of similar examples as proof it couldn't happen. If it just a comment on how puzzling it might appear (to some people) then my comment is moot.


What if we didn't have an example of something physical
that goes from zero size to infinite size? Would we find
the idea puzzling? More puzzling than something physical
that goes from zero size to finite size?

The two cases are equally plausible in an objective sense. I suppose I can see why you might find one more puzzling than the other.

Hornblower
2013-Nov-22, 04:48 PM
I personally find the idea that the vast amount of "stuff" of the universe as we know it once had a zero volume to be absurd. I have no first principles problem with having it in a microscopically tiny but nonzero volume, in a stupendously hot and dense state. Since the latter is the farthest back to which we can extrapolate with the perhaps misnamed Big Bang theory, I find the former to be a moot point.

Robert Tulip
2013-Nov-23, 09:51 AM
GR predicts a singularity at T=0. QM says there can be no such thing. Does that mean one of them is broken?
I'm not sure that broken is the right word, since we are talking about limit conditions. Relativity does not mean Newtonian mechanics is broken, only that its field of operation is less than classical mechanics thought.

This point Jeff has summarised regarding the conflict between GR and QM at the limit point of the origin of the universe is central to my original question, how something could have come from nothing, and how science addresses the problem of the zero size of the universe apparently implied by the singularity theory derived from GR.

My very limited understanding, speaking as a philosophy graduate rather than a physicist, is that
(i) GM implies an infinitesimal singularity, and that the universe therefore had no size, but
(ii) the impossibility of this implication is seen through QM, and
(iii) the principle of consistency means that QM and GR should be reconcilable in a theory of everything.

Is that right?

On a related point, in calculus (http://en.wikipedia.org/wiki/Calculus) integration uses the concept of infinitesimal distance to define the angle of a tangent to a curve and the area beneath the curve. So we find that the inverse of infinity, continuity, is a practical tool in mathematics. This looks a bit like division by zero to define a point, with the Zeno paradox (http://en.wikipedia.org/wiki/Zeno%27s_paradoxes) bearing comparison to the Big Bang question of why GR suggests something came from nothing.

Thanks to everyone who has posted in this thread, the discussion has been very educational.

Jeff Root
2013-Nov-23, 11:16 AM
I want to point out something that seems obvious, but is
rarely mentioned explicitly.

At its simplest, general relativity predicts a singularity at a
point in time in the past based on the assumption that the
mass-energy of the volume of expanding space is constant.
No new matter is created. Looking backward, that results in
increasing density going all the way back to T=0, at which
point the density would have been infinite. If instead the
mass-energy of the volume was increasing over time during
the earliest moments, then the density at those very early
times would not have been so high. The mass-energy of the
volume could have been increasing as fast as or faster than
the increase in volume, so that the density at the earliest
moments could be the same as or lower than the density at
later moments. If the mass-energy of the volume increased
so as to keep pace with the volume, the density could have
remained constant all the way back to T=0, so the density
would not be infinite at that point, and would not have a
value in conflict with quantum mechanics after that.

-- Jeff, in Minneapolis

.

Strange
2013-Nov-23, 01:31 PM
At its simplest, general relativity predicts a singularity at a
point in time in the past based on the assumption that the
mass-energy of the volume of expanding space is constant.
No new matter is created.

That is an interesting point. I'm not sure how that squares with the fact that (as I understand it) there is no easy way to define energy in GR and that conservation of energy may not make sense on a cosmological scale.

Jeff Root
2013-Nov-23, 02:08 PM
Right. My understanding which certainly may be wrong is
that the standard model without a nonzero cosmological
constant (dark energy) assumes that a constant amount
of stuff is present in the volume modeled. Which is why
the density is modeled as infinite at T=0. A wide variety
of different interpretations of dark energy could allow for a
reduced energy density at the earliest times, but all sorts
of other possible mechanisms not involving dark energy
could have the same effect.

I like the idea that energy is conserved on the scale of the
Universe, and that the sum of all negative gravitational
potential energy plus all kinds of positive energy is always
zero, but I have no idea whether that makes any sense
when dark energy is brought into the picture.

-- Jeff, in Minneapolis

Selfsim
2013-Nov-23, 10:02 PM
...The only aspect that decides whether the function goes to infinity in finite time is what the function does before reaching the limit point, and over that domain everything is finite. Rather than thinking of it as the function reaching infinity, think of it as whether the function diverges ... etc ...Hmm ... methinks we've reached this same point before (in past threads) ...

Let me see: I accept your point .. and I personally accept both the incompleteness and the semantic arguments.

My personal 'takeaway' from this discussion, tends to reinforce the meaning I associate with 'unknown'.

Sometimes there is little further return which comes from dwelling on things which our minds might see as being ponderable, but nontheless, remain 'unknown' in spite of the pondering efforts.

Thanks to all, for the conversation .. now its onto other things (for me) ..

Exposed
2013-Nov-24, 02:03 AM
Isn't it true that infinity is an abstract concept? In other words there nothing in the physical world that can be confirmed to be infinite in size or quantity. We can only come up with "mind exercises" such as start with the number one and add one.... forever. But infinity as a tangible physucal property has never been demonstrated. Hence to me the infinite universe is much akin to the multiverse, bothe are mathmatical concepts that can not be proven.


While not really a confirmation, the latest WMAP data cannot detect even the slightest bit of curvature in the observable universe, which if taken at face value does suggest a flat, infinite universe.

WayneFrancis
2013-Nov-25, 12:09 AM
As I've said way too many times, it shows why the
idea of the Universe going from zero volume to infinite
volume is more puzzling than the idea of the Universe
going from zero volume to finite volume. One case
involves one puzzle, while the other case involves two
puzzles. This is only relevant to the fact that Wayne
said to Kevin that the two cases are equally puzzling.
That clearly is not true.


And this is when I point out that you take your analogies WAY beyond their domain of applicability.

Your examples have been shown to be faulty. For example that a pencil line, or in my case a photon, could go from zero to infinity. But since it goes against your preconception you place arbitrary restrictions to stop them going to infinity from actually counting as evidence. Invoking the "Have you seen it?" argument is disingenuous. By your definition even something that is infinite would not pass your tests because your tests include conditions that would fail them.




On the contrary, we have one example of an egg-laying,
duck-billed, beaver-tailed, otter-footed, venomous
mammalian species. That means it exists.


And we have 1 universe that may be infinite and maybe homogeneous and isotropic across the entire, infinite, expanse. Just because you throw out any examples of something that maybe infinite doesn't mean they aren't. Take for example the stability of a proton. We do not know if they decay or not. They might be stable for an infinite amount of time. They might decay but we still haven't observed it. The observation of not seeing one decay only puts lower limits on the half-life of proton. Even if we never see on decay in a billion years it doesn't mean that they don't have a half life. But with your restrictions we can't say that they are stable because no one has ever observed a proton for an infinite amount of time.



What if we didn't have an example of an egg-laying,
duck-billed, beaver-tailed, otter-footed, venomous
mammalian species? What would we expect?


Another creationist tactic "absence of evidence is not evidence of absence" the difference between the universe and the platypus, if we've never seen it is this.
The evidence of if the universe being infinite or not.
1) We have seen no evidence one way or another
2) Various accepted models support universes of both types equally well
3) We have put lower bounds on the size of the universe but there are no current upper bounds
Basically we can say "We don't know"

The evidence for or against a platypus
1) Evolutionary evidence shows mammals descended from egg laying reptiles.
2) We have fossilised evidence of related species.
3) We know of other venomous mammals.
4) We know of other monotremes


Sure back in the late 1700s scientists were doubtful of their existence or more appropriately ignorant of their existence. When the first specimens were found their was doubt to its authenticity but then they didn't have the supporting evidence we do now. Scientist today wouldn't be as sceptical of the existence save one detail in that we've searched the habitat of such an animal exstensively. The rest of the evidence we can say "sure an animal like that could exists".

Creationist will have you believe that evolution is a lie. That transitions of species doesn't happen. Science can predict species that we haven't even found evidence of yet. For example before they where found it was theorised that there should be transitional species between land walking mammals like those of the Pakicetus and modern whales. Not only was it theorised they should exist but science predicted not only what the traits would be but also where their fossils should be found. So for a creature like a platypus, scientist would be able to point us to were they would expect such a creature to live. If at that point after extensive searching none is found we have a higher confidence that the creature probably does not exists.

This is far different from what you want. Most scientists say "We don't know and can never probably know if the universe is infinite". Because of the nature of the question we can only find evidence of the opposite that the universe is finite. But to date we have found no such example of that either. So what does that say? Much like a platypus like creature that didn't exists can we say "well we've looked really hard but can't find any evidence that it is finite ... thus it is more likely that it is infinite?" Most scientist would probably agree that is getting into philosophy.




What if we didn't have an example of something physical
that goes from zero size to infinite size? Would we find
the idea puzzling? More puzzling than something physical
that goes from zero size to finite size?

-- Jeff, in Minneapolis

And again you are pushing your examples beyond their domains of applicability. Show me another universe that goes from zero to finite size and I'll say you have evidence that our universe is more likely to be finite. Until then the models don't point one way or another for the size of the universe. The evidence only points to a lower boundary that is orders of magnitude larger then the visible universe. Much like the no evidence of a proton decaying only points to a lower bounds of the proton's half life. Until a model that supports proton decay has more supporting evidence in the domain that deals with proton decay then a model that doesn't have protons decaying, ie a model where baryon numbers are not conserved all we can say is that we don't know if protons decay. We have no evidence that they do decay and we won't know if baryon numbers are conserved unless we find evidence that they are not. So in this sense an infinite universe is much like proton decay in a way.

Jeff Root
2013-Nov-25, 01:04 AM
Your examples have been shown to be faulty. For example
that a pencil line, or in my case a photon, could go from
zero to infinity.
A pencil line or photon cannot go from zero to infinity.

But that wasn't the point. The point was that nobody has
ever observed a pencil line or photon or anything else go
to infinity.



But since it goes against your preconception you place
arbitrary restrictions to stop them going to infinity from
actually counting as evidence. Invoking the "Have you
seen it?" argument is disingenuous. By your definition
even something that is infinite would not pass your tests
because your tests include conditions that would fail them.
Wayne,

In post #77, I requested of you ...


Now you name a few examples of physical things that
have gone from zero to infinite value.
Can you tell me why I requested that of you? Can you
tell me what I was trying to do? Can you tell me what
the point was of my asking?

Follow the link and read the post again so that you see
it in context.

-- Jeff, in Minneapolis

WayneFrancis
2013-Nov-26, 03:17 AM
A pencil line or photon cannot go from zero to infinity.



The pencil line can't go from zero to infinity because the pencil has a finite resource.
The pencil line going from zero to a finite size is not puzzling because we completely understand where the pencil came from and the mechanism of making a pencil line.
The source of and the mechanism by which the universe was created is completely unknown but yet you still try to push the analogies way beyond their domain of applicability.
The photon can go from zero to infinity. The issue that a photon will probably run into something doesn't change the physics that there is no known mechanism where a photon, by itself, will pop out of existence.





But that wasn't the point. The point was that nobody has
ever observed a pencil line or photon or anything else go
to infinity.


No one has observed a brontosaurus walking around, it doesn't mean they didn't walk around 150 million years ago. This is the problem. Many of the arguments you are using are straight out of creationist play books.
no one can ever observe something infinite..they can observe a portion of something that is infinite.
You yourself have said that the universe may be infinite in size but according to your logic here since no one has observed the universe in its infinite entirety it couldn't be infinite meaning your self contradictory.




Wayne,

In post #77, I requested of you ...

Can you tell me why I requested that of you? Can you
tell me what I was trying to do? Can you tell me what
the point was of my asking?

Follow the link and read the post again so that you see
it in context.

-- Jeff, in Minneapolis

I did, it seems you want me to "realise" nothing goes from zero to infinity. The problem is I gave you examples that can go from zero to infinity. You then put constraints that automatically rule out anything that could be infinite by requiring it to be observed as infinite which is an impossible task of observation. If that isn't your reason then
1) Explain what your reason was
and
2) Explain why you put constraints you should know would rule out any example that fit the first request.

You might as well say "You can't show me anything that is black!" then say "You can't observe that because it is black and thus can't be seen because it emits no photons thus can't be seen"

So at this point here are 3 things that can be infinite.
1) a photon
2) time
and for you something physical
3) a proton.

Because at this point if baryon conservation is true there is no known mechanism for a proton to decay without outside intervention.

But I'm sure you'll find a problem with that...like no one has observed a proton for an infinite amount of time. Just because the lower bounds of a possible half-life, if there is even one, is estimated at about 6.6×1033 years.
For those following along that is
6,600,000,000,000,000,000,000,000,000,000,000 years
The age of the universe is only
14,000,000,000
so that is over 4,700,000,000,000,000,000,000 times the age of the current age of the universe
But because Jeff requires a proton to be observed for an infinite amount of time before saying that protons may have no half-life, even if there are no models that point to a half life of something stupid like 1x1033100 it still wouldn't be enough.

Jeff Root
2013-Nov-26, 06:13 AM
A pencil line or photon cannot go from zero to infinity.

The pencil line can't go from zero to infinity because
the pencil has a finite resource.
That is one reason, yes.




The pencil line going from zero to a finite size is not
puzzling because we completely understand where the
pencil came from and the mechanism of making a pencil line.
That's probably true, but mainly it isn't puzzling because
it is something that we observe frequently.




The source of and the mechanism by which the universe
was created is completely unknown but yet you still try to
push the analogies way beyond their domain of applicability.
I don't think I've pushed any analogies. The analogies I
used as examples are of no consequence. You're making
a big deal over nothing.




The photon can go from zero to infinity. The issue that
a photon will probably run into something doesn't change
the physics that there is no known mechanism where a
photon, by itself, will pop out of existence.
Oh! Interesting. I wasn't expecting that. So you don't
understand the concept of infinity. That's a really tough
thing to try to explain.

A photon can't go to infinity. There is no such place.

But those facts are irrelevant to the point I was trying
to make.

Also, in our Universe, a photon travelling through deep
space has a better than even chance of never running
into anything and being absorbed. Photons popping out
of existence hadn't occurred to me, but that idea is also
irrelevant.




But that wasn't the point. The point was that nobody
has ever observed a pencil line or photon or anything
else go to infinity.
No one has observed a brontosaurus walking around, it
doesn't mean they didn't walk around 150 million years
ago.
Ha! Right, it doesn't mean that. But ... they didn't walk
around 150 million years ago, or any other time.

The brontosaurus is no more. Somebody stuck the skull
of one dinosaur on the body of another, and called the
result "brontosaurus", but the skull and body eventually
were discovered to be different species, so the name
"brontosaurus" now refers only to a fictional critter.

But of course, people have seen lots of other four-legged
animals walk around. And people have seen fossilized
skeletons that were called "brontosaurus" not too long
ago, as well as fossilized skeletons of similar critters.
So people are pretty familiar with the idea of something
like a brontosaurus walking around.



This is the problem. Many of the arguments you are
using are straight out of creationist play books.
Not literally, but interesting if they are the same or
even just similar. I had no idea.

Is it really a problem?



no one can ever observe something infinite..
Right! You're halfway there!

You are also indicating that you *do* understand the
concept of infinity, at that.



they can observe a portion of something that is infinite.
You yourself have said that the universe may be infinite
in size but according to your logic here since no one has
observed the universe in its infinite entirety it couldn't
be infinite meaning your self contradictory.
No, you don't know what my logic is, even though I've
explained it at least a half-dozen times.




Wayne,

In post #77, I requested of you ...

Can you tell me why I requested that of you? Can you
tell me what I was trying to do? Can you tell me what
the point was of my asking?

Follow the link and read the post again so that you see
it in context.
I did, it seems you want me to "realise" nothing goes from
zero to infinity.
That's close. But not on the mark.

I wanted you to realize that nothing physical has ever
been observed to go from zero to infinite value.

The "from zero" isn't important, and the "value" isn't
important. The "physical", however, is important, and
the part about "has ever been observed" is critical.
You missed out that part, and it shows that you didn't
understand what I have been arguing.



The problem is I gave you examples that can go
from zero to infinity. You then put constraints that
automatically rule out anything that could be infinite
by requiring it to be observed as infinite which is an
impossible task of observation.
The problem is apparently reading comprehension.

I suggested to you to again read my post #77, in
which I first requested you to provide an example
of something. Here is what I asked:


Now you name a few examples of physical things that
have gone from zero to infinite value.
I didn't ask for examples of things that can go from
zero to infinite value. I didn't ask for examples of
things that might go from zero to infinite value.
I asked for examples of things that have gone
from zero to infinite value. That requirement was
in the very first request.



If that isn't your reason then
1) Explain what your reason was
and
2) Explain why you put constraints you should know
would rule out any example that fit the first request.
I put the constraints in the first request, and I did
that because the point was to demonstrate to you
that something becoming infinite is more puzzling
than something becoming finite.

What is familiar usually is not puzzling. I gave three
examples of physical things going from zero value to
finite value, showing that such a transition is familiar,
and therefore not likely to be puzzling. I knew that
you would not be able to come up with any example
of a physical thing that has gone from zero to infinite
value, showing that such a transition is unfamiliar and
therefore likely to be puzzling.

Yes, this is elementary simple. But you haven't been
getting it even after I've explained it to the point that
even I am tired of repeating myself.



So at this point here are 3 things that can be infinite.
1) a photon
2) time
and for you something physical
3) a proton.

Because at this point if baryon conservation is true
there is no known mechanism for a proton to decay
without outside intervention.
All irrelevant.

First off, I consider all three to be physical, although
many people would likely disagree about time.

Second, none of these are known to be infinite.

A photon cannot be infinitely old if the Universe is not
infinitely old.

Whether time is infinite is a completely open question.
Time certainly hasn't gone from zero to infinite value.
Starting at the Big Bang, time has gone from zero to
about 13.7 billion years.

A proton can't be infinitely old if the Universe is not
infinitely old, either. And even if protons never decay
and are never destroyed by anything, they will never
be infinitely old.

Third, all three of those examples are the same: time.



But I'm sure you'll find a problem with that...like no one
has observed a proton for an infinite amount of time.
Good prediction. Inductive logic in action.



But because Jeff requires a proton to be observed for an
infinite amount of time before saying that protons may
have no half-life, even if there are no models that point
to a half life of something stupid like 1x1033100
it still wouldn't be enough.
Partially correct, and partially not.

You can't infer anything about what I think the half-life
of protons might be from my argument here. So that
part is wrong.

The part that is correct is that it isn't enough to make
infinite protons -- or even just infinitely-long-lasting
protons -- a familiar item.

You said to Kevin that a transition from zero volume
to finite volume seems just as puzzling as a transition
from zero volume to infinite volume. I showed long
ago that that isn't so.

-- Jeff, in Minneapolis

WayneFrancis
2013-Nov-26, 06:33 AM
That is one reason, yes....
BLAH BLAH BLAH

-- Jeff, in Minneapolis

There you go. This whole post screams of exactly what I mean. You are using creationist arguments. There is a problem with that because it is more lawyer tactics then anything and very far from the scientific method. So sorry Apatosaurus, rolls eyes. The issue is you are saying because no one has seen it then it didn't exist which is the point but hand wave away. My proton example is valid. Unless you want to show a model with observations that support proton decay. But no... you hand wave away that too.

Your conditions to prove something can be infinite would require a god and since that isn't going to happen you've happily dismissed things that are infinite because we humans are not going to be around long enough.

You think your clever but you are using nothing more then semantics, hand waving and straw men and personally for me it tarnishes much of what you say even tho that is true. So feel all clever but being disingenuous is very unbecoming of you Jeff.

Shaula
2013-Nov-26, 07:20 AM
My favourite bit is that by assuming the universe has zero volume by making some form of creation event including a singularity part of your model to argue from you are arguing that the density of the universe went from an infinite value to a finite value. Apparently that makes sense but the reverse does not.

Selfsim
2013-Nov-26, 07:41 AM
Well, I'd decided to stay out of this previously because it became clear for me that Jeff's point seems quite empty (for me) ... moot almost.

I'd like to ask Jeff: Beyond what you have stated numerous times, what exactly is your overall point?
Yes unfortunately, there is a pun in this question. :p :) .. (see the thread title).

The BB Theory is a theory about the evolution of the Universe ... it isn't a theory about its origin.

The gravitational singularity is based on the idea that density is infinite at the instant of origination where r=0.

The R-W metric shows that space-time is undefined at r=0, rather than being singular. As a result, BB cosmology at r=0 and t=0 is not defined.
It simply illustrates the incompleteness of the theory.

Aside from these facts, I'll have a guess that Jeff might be attempting to demonstrate that the idea of something infinite, emerging from something finite, has less going for it than any of the other alternatives, and thus should not be considered as a mainstream view(?).. But I only offer that, as a guess as to Jeff's intention(?)

Over to you, Jeff ...

PS: Shaula beat me to it ... I concur with the point made.

Jeff Root
2013-Nov-26, 03:24 PM
Well, I'd decided to stay out of this previously because
it became clear for me that Jeff's point seems quite
empty (for me) ... moot almost.
My point was of little consequence, and very boring.



I'd like to ask Jeff: Beyond what you have stated
numerous times, what exactly is your overall point?
Nothing beyond what I stated numerous times. Wayne
said that a transition from zero volume to finite volume
seems just as puzzling as a transition from zero volume
to infinite volume. I demonstrated that that isn't so,
and the rest was arguments against it that were mostly
irrelevant to what I actually said.



The BB Theory is a theory about the evolution of the
Universe ... it isn't a theory about its origin.

The gravitational singularity is based on the idea that
density is infinite at the instant of origination where r=0.
The singularity is independent of the density, I think.
Hawking and Penrose showed in 1968 that according
to GR, the Universe had a singularity in time. When
you say "gravitational singularity", you may mean
something more than that. As you can tell from my
posts #171 and #173, I favor the idea that not all the
stuff in the Universe was present all the way back to
t=0, so the density would not have been infinite or
approaching infinite. The density could even have
increased for a while until it reached a maximum.



The R-W metric shows that space-time is undefined
at r=0, rather than being singular. As a result, BB
cosmology at r=0 and t=0 is not defined.
It simply illustrates the incompleteness of the theory.

Aside from these facts, I'll have a guess that Jeff might
be attempting to demonstrate that the idea of something
infinite, emerging from something finite, has less going
for it than any of the other alternatives, and thus should
not be considered as a mainstream view(?).. But I only
offer that, as a guess as to Jeff's intention(?)

Over to you, Jeff ...
That is a completely fair characterization.

-- Jeff, in Minneapolis

KABOOM
2013-Nov-26, 03:40 PM
While not really a confirmation, the latest WMAP data cannot detect even the slightest bit of curvature in the observable universe, which if taken at face value does suggest a flat, infinite universe.

Thanks for the response. I presume that from this arises the calculation as to the "minimum size" of the universe (to the extent that the universe is finite in size). Do you or anyone know how many times bigger than the observable universe (which I believe has a diameter of ~ 94 billion light years) the total universe would have to be to be consistent with showing no signs of curvature (i.e, it could still be curved it is just that we can't detect it because the obervable universe is too small a subset of the entire universe)? Thanks and I do understand that the answer to my question is simply a minimum.

Strange
2013-Nov-26, 03:41 PM
Nothing beyond what I stated numerous times. Wayne
said that a transition from zero volume to finite volume
seems just as puzzling as a transition from zero volume
to infinite volume. I demonstrated that that isn't so

No, you demonstrated that you think it isn't so, based on the fact you have seen some finite things but you have never seen an infinite thing. Not exactly a compelling argument.

Jeff Root
2013-Nov-26, 05:20 PM
I demonstrated that everyone sees things go from zero
to finite size every day, while nobody has ever seen
anything go from zero to infinite size, so such an occurrance
is clearly less familiar to everyone, not just me. The idea
of an occurrance of a kind that nobody has ever seen will
surely be more puzzling to everyone, including you and
Wayne, than the idea of an occurrance of a kind that you
witness daily.

If something going from zero to finite size is puzzling, it
is a puzzle shared by something going from zero to infinite
size. The puzzle of how something can go to infinite size
is in addition to that shared puzzle, so there is no way the
scenarios can be equally puzzling.

-- Jeff, in Minneapolis

Strange
2013-Nov-26, 05:29 PM
The idea
of an occurrance of a kind that nobody has ever seen will
surely be more puzzling to everyone, including you and
Wayne, than the idea of an occurrance of a kind that you
witness daily.

Nope. Another fallacy to add to the list.


The puzzle of how something can go to infinite size
is in addition to that shared puzzle

Nope. It is exactly the same puzzle. (Are there degrees of impossible, I wonder.)

Jeff Root
2013-Nov-26, 05:52 PM
The idea
of an occurrance of a kind that nobody has ever seen will
surely be more puzzling to everyone, including you and
Wayne, than the idea of an occurrance of a kind that you
witness daily.
Nope. Another fallacy to add to the list.
Would it be acceptable to you if I said "most people"
instead of "everyone, including you and Wayne" ?
Other than that, I don't see any possible fallacy.




The puzzle of how something can go to infinite size
is in addition to that shared puzzle
Nope. It is exactly the same puzzle.
They are obviously distinctly different. Can you
explain why you think they are exactly the same?



(Are there degrees of impossible, I wonder.)
What are you referring to as "impossible" here?
There are degrees of familiarity and puzzlement,
which are what I was talking about in response to
Wayne's assertion.

-- Jeff, in Minneapolis

Strange
2013-Nov-26, 06:35 PM
Would it be acceptable to you if I said "most people"
instead of "everyone, including you and Wayne" ?

Only if you have some evidence that most people agree with you. Based on the comments on this forum every time you bring this up, that doesn't seem to be the case. Has anyone agreed with you?


They are obviously distinctly different. Can you
explain why you think they are exactly the same?

The are obviously the same. (Apart from false analogies, I am happy to use the same level of evidence that you have.)

I think someone has given a mathematical justification (probably in every thread where you bring this up). I don't think I can be bothered to trawl back through 7 pages to try and find it.


What are you referring to as "impossible" here?

I was putting it in parentheses because I know it isn't your main point. But they are equally impossible and therefore equally puzzling.

KABOOM
2013-Nov-26, 08:43 PM
I demonstrated that everyone sees things go from zero
to finite size every day, while nobody has ever seen
anything go from zero to infinite size, so such an occurrance
is clearly less familiar to everyone, not just me. The idea
of an occurrance of a kind that nobody has ever seen will
surely be more puzzling to everyone, including you and
Wayne, than the idea of an occurrance of a kind that you
witness daily.

If something going from zero to finite size is puzzling, it
is a puzzle shared by something going from zero to infinite
size. The puzzle of how something can go to infinite size
is in addition to that shared puzzle, so there is no way the
scenarios can be equally puzzling.

-- Jeff, in Minneapolis

I'm a layperson, but all of your examples of "things going from zero to something finite in size" to me don't hold up because in actuality none of them start with zero. If you are starting with raw ingredients, then mix/bake and create food you simply cooked food. You started with something, not zero, but rather ingredients. Creating an image on a blank piece of paper is simply taking physical elements such as lead, ink or paint and transferring some of it onto your canvas/paper.

I struggle with the concept of an infinite universe although I also struggle as to how a finite universe could be hatched from nothing. I read Hawkins book "A universe from nothing" in which he conveyed that "phase changes" at the quantum level could in theory do such (although I confess I would feel better in grasping this concept if somehow in a blank room in a lab somewhere, phase changes could be stimulated that would effectively create matter where it didn't previously exist).

Jeff Root
2013-Nov-27, 03:10 AM
KABOOM,

What I said about the cake:



I have made cake go from zero volume to a cubic decimeter
and back to zero volume again.
If you believe the cake did not start from zero volume,
what volume do you think it had?

What I said about the pencil line:



I have made a pencil line on paper go from zero to five
centimeters long.
If you believe the pencil line did not start from zero
length, what length do you think it had?

What I said about the light beam:



I have made a beam of light go from zero to 385,000 km
long, so that it reaches from Earth to the Moon.
If you believe the light beam did not start from zero
length, what length do you think it had?

-- Jeff. in Minneapolis

tusenfem
2013-Nov-27, 07:27 AM
Okay, I think this "discussion" has reached the point of no further added value.
thread closed
(naturally, if anyone thinks this should be reopened, please report this message)