Is Krauss looking at this right?

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I agree completely with the above.

And disagree with the above.

If the universe "must appear to be homogeneous and isotropic to an observer at all times in the future and the past", then it is consistent with my previous statement that says:

"It is not conceivable (IMHO) that we currently live a privileged period of the Universe, a period so special that allows us to observe the Universe in a different way than future generations on future planets would observe. To me, there MUST be nothing special in our position in space (cf cosmological principle) and in time: IOW there is no privilege to our position in spacetime."

Ok. You disagree with this statement:

The supposition of the cosmological principle leads to Alexander Friedmann's standard models of cosmological evolution...

It is a proven scientific fact. Does that matter? I could quote some supporting material if it does...

Friedmann equations -- Assumptions

Main article: Friedmann-Lemaître-Robertson-Walker metric

The Friedmann equations start with the simplifying assumption that the universe is spatially homogeneous and isotropic, i.e. the Cosmological Principle; empirically, this is justified on scales larger than ~100 Mpc. The Cosmological Principle implies that the metric of the universe must be of the form:

$ds^2 = {a(t)}^2 ds_3^2 - c^2dt^2$

where $\! ds_3^2$ is a three dimensional metric that must be one of a) flat space, b) a sphere of constant positive curvature or c) a hyperbolic space with constant negative curvature. The parameter $\! k$ discussed below takes the value 0, 1, -1 in these three cases respectively. It is this fact that allows us to sensibly speak of a "scale factor", $\! a(t)$.

Wikipedia -- Freidmann Equations -- Assumptions

I guess you're free to disagree. Why do you think reality follows the principle of a non-evolving universe? Is it because you like that principle, or because you prefer to imagine reality following the principle?

I mean... if your beliefs about reality are shaped by the way you prefer to imagine it even when all the evidence and facts disagree then it would hardly do any good for me to point out evidence and facts. You would just say "I disagree".

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Ok. You disagree with this statement:

It is a proven scientific fact. Does that matter? I could quote some supporting material if it does...

I guess you're free to disagree. Why do you think reality follows the principle of a non-evolving universe? Is it because you like that principle, or because you prefer to imagine reality following the principle?

I mean... if your beliefs about reality are shaped by the way you prefer to imagine it even when all the evidence and facts disagree then it would hardly do any good for me to point out evidence and facts. You would just say "I disagree".

From Wiki:

The FLRW metric starts with the assumption of homogeneity and isotropy of space. It also assumes that the spatial component of the metric can be time-dependent.

The bold part in the quote is an assumption, it is not a "proven scientific fact".

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Yes. If one assumes that the universe follows the cosmological principle then one can use the Friedmann model. The model assumes it. It is a postulate of the model.

This is the fact:

The supposition of the cosmological principle leads to Alexander Friedmann's standard models of cosmological evolution...

I'm not sure you exactly know what you're disagreeing with. It was the above quote.

Edited by Iggy
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Iggy,

OK, I think I am understanding the assumptions and the nescessary deductions and conclusions a little better.

But still this. What mechanism causes everything else to be caught in the hubble flow, so that it will be dragged out beyond our event horizon, eventually, but gives a pass, to our "local" group of galaxies, and will leave them to interact for the same "eventual" term?

Why would not the familiarity we share with the galaxy on our right and its with ours, not likewise be shared between it, and the galaxy on its right. And in this way bind together strings of galaxies, against the force of the hubble flow?

Could there not be a "tension" that exists between galaxies that would allow for strings of galaxies to hold together, while the voids between grow in size? Again, with the visual of the voids being the air and the galaxies being the soap and water, in a handful of suds.

This would allow for the observations of universal expansion, but not demand the "unhooking" of the rest of the universe, from our "island" group. There may be a larger dynamic going on, that would not require that Krauss is right.

Regards, TAR2

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Galaxies are grouped into clusters and they are separated by much greater distances, but the large scale structure do look like strings in a web.

Simulation of the large-scale structure of the cosmos. The image spans about 400 million light years across.

http://en.wikipedia.org/wiki/Galaxy#Larger-scale_structures

Large-scale structure

Sky surveys and mappings of the various wavelength bands of electromagnetic radiation (in particular 21-cm emission) have yielded much information on the content and character of the universe's structure. The organization of structure appears to follow as a hierarchical model with organization up to the scale of superclusters and filaments. Larger than this, there seems to be no continued structure, a phenomenon which has been referred to as the End of Greatness.

Walls, filaments and voids

DTFE reconstruction of the inner parts of the 2dF Galaxy Redshift Survey

The organization of structure arguably begins at the stellar level, though most cosmologists rarely address astrophysics on that scale. Stars are organized into galaxies, which in turn form clusters of galaxies and superclusters that are separated by immense voids, creating a vast foam-like structure sometimes called the "cosmic web". Prior to 1989, it was commonly assumed that virialized galaxy clusters were the largest structures in existence, and that they were distributed more or less uniformly throughout the universe in every direction. However, based on redshift survey data, in 1989 Margaret Geller and John Huchra discovered the "Great Wall", a sheet of galaxies more than 500 million light-years long and 200 million wide, but only 15 million light-years thick. The existence of this structure escaped notice for so long because it requires locating the position of galaxies in three dimensions, which involves combining location information about the galaxies with distance information from redshifts. In April 2003, another large-scale structure was discovered, the Sloan Great Wall. In August 2007, a possible supervoid was detected in the constellation Eridanus. It coincides with the 'WMAP Cold Spot', a cold region in the microwave sky that is highly improbable under the currently favored cosmological model. This supervoid could cause the cold spot, but to do so it would have to be improbably big, possibly a billion light-years across.

Another large-scale structure is the Newfound Blob, a collection of galaxies and enormous gas bubbles which measures about 200 million light years across.

In recent studies the universe appears as a collection of giant bubble-like voids separated by sheets and filaments of galaxies, with the superclusters appearing as occasional relatively dense nodes. This network is clearly visible in the 2dF Galaxy Redshift Survey. In the figure, a three dimensional reconstruction of the inner parts of the survey is shown, revealing an impressive view on the cosmic structures in the nearby universe. Several superclusters stand out, such as the Sloan Great Wall, the largest structure in the universe known to date.

http://en.wikipedia.org/wiki/Large-scale_structure_of_the_cosmos#Large-scale_structure

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Iggy,

OK, I think I am understanding the assumptions and the nescessary deductions and conclusions a little better.

But still this. What mechanism causes everything else to be caught in the hubble flow, so that it will be dragged out beyond our event horizon, eventually, but gives a pass, to our "local" group of galaxies, and will leave them to interact for the same "eventual" term?

With general relativity the attractive force of gravity falls off with the square of the distance and the repulsive term (the cosmological constant) increases proportionally with distance. The result is that things near you will want to be accelerated toward you and things further away will want to be accelerated away.

The simple answer is that the equations of gravity determine the gravitational interaction.

Why would not the familiarity we share with the galaxy on our right and its with ours, not likewise be shared between it, and the galaxy on its right. And in this way bind together strings of galaxies, against the force of the hubble flow?

If you had a string of evenly spaced galaxies you would get clumps that collapse around the most massive parts and end up with a string of clumps of galaxies where each cluster accelerates away from the others.

Like Spyman points out, the universe is going through something like that process now where small collections of matter are fighting to collapse and the larger collection which they make up are fighting to expand. The result is a bit like ripping cotton candy to pieces.

Could there not be a "tension" that exists between galaxies that would allow for strings of galaxies to hold together, while the voids between grow in size?

Tension falls off with the square of distance. The force working against tension increases linearly with distance. When forces are not in balance you have acceleration. Over smaller distances tension is the stronger force and the acceleration is toward collapse. Over larger distances tension loses and the acceleration is toward expansion.

Again, with the visual of the voids being the air and the galaxies being the soap and water, in a handful of suds.

This would allow for the observations of universal expansion, but not demand the "unhooking" of the rest of the universe, from our "island" group. There may be a larger dynamic going on, that would not require that Krauss is right.

Regards, TAR2

The further away things are the faster they're moving away from us. The large scale structure isn't being held together. The small scale structure will all collapse in on itself much like the Andromeda galaxy is doing with the Milky Way.

Edited by Iggy
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Iggy,

Makes sense, but I can't help but notice that the things that are moving away from us the fastest, are the youngest things we see. That would indicate to me, that that is what those objects were doing a very long time ago, and I am not sure how you use these observations to determine what the universe is currently doing. Could one not also make the deduction that since the objects relatively close to us, are behaving in a certain fashion, that that behavior would be more representative of what the whole universe has been doing recently, than going by the behavior of objects doing what objects did in much earlier epochs of our universe's history? Why could these facts not point to a universe whose expansion is slowing?

If you had an evenly spaced string of galaxies, and neighbors were moving toward a local center, then half the bodies we viewed, would be coming toward us, if they were on the other side of their local center, and those on our side of the local center would be moving away from us. There would be no particular reason for the centers to be moving away from each other. In fact, it seems they might tend to orbit each other, or perhaps a less local center.

Now, forgive me, I know this stuff has already been figured out. And I appreciate your patience with me, explaining what it is we have figured out, and why, but it always bothers me, that we can be so sure of what the universe is currently doing, when we can't see even what is happening on the other side of our own galaxy for several hundred

thousand years. In fact we NEVER get to see what is happening on the other side of our own Galaxy because of the central dust and possible black hole blocking our view.

I still maintain, that there is a certain "godlike" perspective, that one must take to claim to know what the universe is currently like, and what it will be like in 100million years. And this perspective is a different one, than the perspective we have when we look up into the sky. And if you have to decide to take one perspective over the other, to determine what is real, the choice is impossible, because both HAVE to be the case.

So we are informed of what the universe is doing in the here and now, and we remember it, and model it, and deduce its history and predict its future, and figure it to both be the case that we see, and the case that we know has to be the case for us to see what we see. I do not think it incorrect to see both, to know both. But I do think it incorrect to consider ones self in sole possession of the Godlike view, when such a view is so plainly impossible. And I do think it incorrect for Krauss to laugh at believers in God, when the universe is so plainly superior to our here and now view of it.

And this perhaps is my major contention with Krauss. That he claims to be the first to know how the universe ends, and he doesn't even suggest why what happens at the end of the universe, would matter.

Regards, TAR2

And if all the forces in the universe are of and in the universe and the universe CAN be understood to have first inflated, then expanded, is not the "flow" generally from faster to slower? And would this not "predict" a slowing to a stop, and possibly an eventual reversal of the flow?

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Iggy,

Makes sense, but I can't help but notice that the things that are moving away from us the fastest, are the youngest things we see. That would indicate to me, that that is what those objects were doing a very long time ago,

Not exactly. The amount of redshift is not only a function of what the galaxy was doing when it was emitted, but what space has done between the galaxy and us between emission and observation.

and I am not sure how you use these observations to determine what the universe is currently doing.

Observations have to be made at several distances in order to model the universe. The observables (things like redshift and luminosity) made at one particular distance (and equivalently from one time in the past) can't be used to solve the matter and dark energy density which is what one needs to know to order to model the past, present, and future of the universe.

Could one not also make the deduction that since the objects relatively close to us, are behaving in a certain fashion, that that behavior would be more representative of what the whole universe has been doing recently,

closer observations are more representative of recent behavior.

than going by the behavior of objects doing what objects did in much earlier epochs of our universe's history? Why could these facts not point to a universe whose expansion is slowing?

Something that is true if expansion is constant can't very well indicate deceleration.

If you had an evenly spaced string of galaxies, and neighbors were moving toward a local center, then half the bodies we viewed, would be coming toward us, if they were on the other side of their local center, and those on our side of the local center would be moving away from us. There would be no particular reason for the centers to be moving away from each other.

If you can't picture it I can offer an analogy. Imagine a long string of rubber covered with ants. Each ant is programmed to walk to the nearest ant larger than itself and it can see roughly 5 inches to accomplish that task. The string is 100 meters long and doubles in size every 5 minutes or so. You'll end up with clusters of ants accelerating away from each other. The greater the distance between clusters the greater the velocity between them.

Now, forgive me, I know this stuff has already been figured out. And I appreciate your patience with me, explaining what it is we have figured out, and why, but it always bothers me, that we can be so sure of what the universe is currently doing, when we can't see even what is happening on the other side of our own galaxy for several hundred

thousand years. In fact we NEVER get to see what is happening on the other side of our own Galaxy because of the central dust and possible black hole blocking our view.

I still maintain, that there is a certain "godlike" perspective, that one must take to claim to know what the universe is currently like, and what it will be like in 100million years. And this perspective is a different one, than the perspective we have when we look up into the sky. And if you have to decide to take one perspective over the other, to determine what is real, the choice is impossible, because both HAVE to be the case.

Our past light cone and the present instant aren't separate perspectives. They are different elements of a complete understanding that is in no way godlike.

Signal delay is not the mysterious problem it apparently seems to you. Cosmology is quite lucky to be able to peer into the past.

So we are informed of what the universe is doing in the here and now, and we remember it, and model it, and deduce its history and predict its future, and figure it to both be the case that we see, and the case that we know has to be the case for us to see what we see. I do not think it incorrect to see both, to know both. But I do think it incorrect to consider ones self in sole possession of the Godlike view, when such a view is so plainly impossible. And I do think it incorrect for Krauss to laugh at believers in God, when the universe is so plainly superior to our here and now view of it.

And this perhaps is my major contention with Krauss. That he claims to be the first to know how the universe ends, and he doesn't even suggest why what happens at the end of the universe, would matter.

Regards, TAR2

That just sounds like rhetoric to me.

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Iggy,

OK, I will try and drop the rhetoric. However the image of a universe that is currently current, and the image of a universe that is currently viewed are not similtaneously possible, because no object can retain its current status in both views.

One is happening to us now. And the others are happening now, but not to us.

It is the ones that are happening now, but not to us, that I maintain are only existant from a series of Godlike perspectives, that are not bound by the speed of light. It has to be happening now, from those godlike perspectives, for us to see it, as we do, later. And it had to have happened before, from those godlike perspectives, for us to see it now. And unfortunately it had to have been continually happening from a mindbending multitude of different godlike perspectives, for it all to wind up right here right now, at every successive moment.

The whole universe winds up right here, right now, all the time. And its been doing that from the beginning.

When you talk of modeling the universe, past, present and future, you can not be seriously considering that you are not taking several godlike perspectives, that are not bound by the speed of light.

That is, that the entire universe was in one visible and holdable state 10billion years ago, another visible and holdable state currently, and to be in yet another visible and holdable state in 100billion years. Three godlike views, that have dropped the requirement, for light to get from one place in the universe to another in the manner that it actually does, and supposes that you could somehow "see" the entire universe at once, from a minds eye, godlike perspective.

When I was thirteen, I had heard that the light of a match (given oxygen) on the moon could be seen from Earth. So I lit a match and held it to the sky (at night). That signal went out, in a half shell at the speed of light, and is "currently", from a godlike perspective, a half shell with a radius of 45 light years. Places in space 44 light years from here saw the light (so to speak) last year, and all places in that direction, 46 lightyears away will see it next year.

That thin expanding half shell of photons, currently exists in reality. It can't not exist. From a Godlike perspective.

We however can never see it again. We can not get to the places it will reach, before it reaches them. We can not signal the places to await its arrival, because any signal now, would be "behind" it and be recieved after the light of the match.

So now, that half shell of photons has a radius of 45ly. In a hundred billion years, it will have a radius of 100billion lightyears plus, and every place it would have passed in that time, would have been emitting photons back in this direction, at the time it passed, so that we are likely to always be able to see other places emitting photons. Some very many "shells" are intersecting here, now. And will always...in my estimation.

Regards, TAR2

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IMHO, I think you should leave God outside of this discussion, it only complicates explanations and muddles interpretations.

Statements like:

If a godlike perspective is an actual thing, then god exists.

make me question what you are trying to say with:

When you talk of modeling the universe, past, present and future, you can not be seriously considering that you are not taking several godlike perspectives, that are not bound by the speed of light.

We humans are capable of modeling the universe's past, present and future, and althought our models could be very wrong it is still we, the HUMANS, that make this views and imagine them, as such we can definately seriously consider that we are taking humanlike perspectives and not godlike ones.

There is no God or supernatural deities included in our scientific models of the universe.

(There might be a God or other supernatural deities but that is a different question.)

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Further more I think the thread is mixing two different but related concepts, models of how the universe evolves and the physics of a continuously accelerating expansion. The simple truth is that Krauss and current scientific cosmological models could be wrong of how the Universe will continue but our understanding of physics and nature is definitive in that a continued accelerated expansion will make the sky darker in the distant future.

I suggest that you separate your inqueries, as whether you want to learn more about current models and observations or if you want to better understand how an accelerated expansion will cause light to be too stretched out to discern from the background radiation in our galaxy.

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When I was thirteen, I had heard that the light of a match (given oxygen) on the moon could be seen from Earth. So I lit a match and held it to the sky (at night). That signal went out, in a half shell at the speed of light...

That light will never reach the galaxy UDFy-38135539 with a confirmed redshift of ~8.55 which in standard models is receding from us with ~1.5 × c.

"UDFy-38135539 (also known as "HUDF.YD3") is the Hubble Ultra Deep Field (UDF) identifier for a galaxy which has been calculated (as of October 2010) to have a light travel time of 13.1 billion years with a present proper distance of around 30 billion light-years. The galaxy is suspected to be the second most distant object yet identified after UDFj-39546284, though UDFy-38135539 is still the most distant object spectroscopically confirmed."

http://en.wikipedia.org/wiki/UDFy-38135539

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...we are likely to always be able to see other places emitting photons. // ...in my estimation.

As for your "estimation", you are of course entitled to retain your own opinion and continue to imagine a view of an universe with different laws of nature than what we have so far discovered or an universe in which the accelerated expansion will come to a stop due to some yet unknown reason.

But our current understanding of physics says that a continued accelerating expansion will make very distant light practically impossible to detect in the far future and our best models from recent measurements indicates that the expansion will continue to accelerate for an eternity.

(Note. I did read parts of this long thread at different separated occasions so I apologize in advance if I managed to miss an important point.)

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OK, I will try and drop the rhetoric. However the image of a universe that is currently current, and the image of a universe that is currently viewed are not similtaneously possible, because no object can retain its current status in both views.

"currently current" is usually called the present instant. "currently viewed" is usually called the past light cone. Both are included on a spacetime diagram. You need only learn to make one to understand how a complete understanding includes both.

When you talk of modeling the universe, past, present and future, you can not be seriously considering that you are not taking several godlike perspectives, that are not bound by the speed of light.

If I agree that modeling spacetime gives a person godlike powers would you give it a try?

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Iggy,

You taught me the spacetime diagram in another thread.

I get it. (sort of)

I am trying to look at this, from a philosophical and scientific and spiritual viewpoint.

Let's say Spyman is right, that I need to drop the Godlike perspective thing.

Where would that get me. The conclusion would be that I, as a human, have the power to model the universe, so percisely, that I can contain it, and as Krauss claims, know how it ends. That I should accept that all the powers and judgements that 100s of thousands of extremely bright and hard working, perceptive mathematical and scientific minds have the whole shooting match figured out already, and my lonely, layman attempts at grasping the reality of reality, are futile. And I should just fall in with what WE already know, and then will believe, like the rest of the gang, that we are smarter than the universe itself, and there is nothing greater than our intellects.

I don't buy it. There is no humility in it. There is no recognition of the overwhelming vastness and superiority that the universe commands over an individual, or 10 billion individuals who have never ventured out of the Sun's system. And we, as a group, have only been looking at this universe and recording our findings for the last 10 thousand years or so.

It is somewhat huberis filled, to suggest that the findings and models of the last 100 years, have brought us to the point where we feel we can claim superiority over the universe. That we know everything important there is to know about it, and can dismiss it, as a venture doomed to darkness, and believe we live in the only time that scientists would be able to know all there is to know about it.

Seems exactly wrong, to me. We, in reality, have little knowledge, and short sight, on our own, as single humans. We need each other, other humans, to know as much as we know. And together we become another organism, a team, a club, a society, a nation, a global community, that has a memory, much longer than 100 years, and vision way past the end of our nose.

Spyman seems to think that we should not talk of God. Yet he believes there is a reality, a universe that currently exists beyond our vision, that we should be concerned about, instead.

My question is, "what is the difference between believing in a reality you can not see, and believing in a consciousness you can not see?" It seems to me that both involve an understanding of, and an association with, that which is beyond our individual lives. And without this ability, we could neither consider God, nor consider a universe that exists, beyond our abilty to see it. Both are models in our heads, of that which exists outside our heads.

At no point is it reasonable to consider that the model in your head is more complete than the thing which you are modeling. That would be a completely inappropriate use of our heads.

Regards, TAR2

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Let's say Spyman is right, that I need to drop the Godlike perspective thing.

Where would that get me. The conclusion would be that I, as a human, have the power to model the universe, so percisely, that I can contain it, and as Krauss claims, know how it ends. That I should accept that all the powers and judgements that 100s of thousands of extremely bright and hard working, perceptive mathematical and scientific minds have the whole shooting match figured out already, and my lonely, layman attempts at grasping the reality of reality, are futile. And I should just fall in with what WE already know, and then will believe, like the rest of the gang, that we are smarter than the universe itself, and there is nothing greater than our intellects.

I don't buy it. There is no humility in it. There is no recognition of the overwhelming vastness and superiority that the universe commands over an individual, or 10 billion individuals who have never ventured out of the Sun's system. And we, as a group, have only been looking at this universe and recording our findings for the last 10 thousand years or so.

It is somewhat huberis filled, to suggest that the findings and models of the last 100 years, have brought us to the point where we feel we can claim superiority over the universe. That we know everything important there is to know about it, and can dismiss it, as a venture doomed to darkness, and believe we live in the only time that scientists would be able to know all there is to know about it.

Let me see if I understand...

I'll quote what Krauss said and bold the key point:

And it should put us, give us some kind of cosmic humility, which is the other thing that should be characteristic of science.

Humility: The recognition that we don't understand everything. Bill Maher talked about it last night. What pompous assholes like Rick Warren, who claim to understand everything, are antagonistic to science. We should realize that there's more we don't understand about the universe than we do. And I wanna give you an example of this.

The far future. What's gonna happen in the far future? Remeber 100 years ago we thought we lived in a static eternal universe. The amazing thing is for civilizations that live in the far future, what will they see? Well, the universe is accelerating. That means all the distant galaxies are going to be carried away from us and eventually they will move away from us faster than the speed of light. It's allowed in General Relativity.

They will disappear. The longer we wait, the less we will see. In 100 billion years any observers evolving on stars (and there will be stars just like our sun in 100 billion years)... any observers in civilizations evolving around those stars will see nothing except for our galaxy, which is exactly the picture they had in 1915.

All evidence of the Hubble expansion will disappear. Why, because we won't see the other galaxies moving apart from us. So they will have no evidence in fact of the Big Bang. They wont see the Hubble Expansion. They won't even know about dark energy. They wont know about the cosmic microwave background -- it will disappear too. It will red-shift away and it turns out for fancy reasons, this plasma in our galaxy, when the universe is 50 times its present age, the microwave background won't be able to propagate in our galaxy. All evidence of the Big Bang will have disappeared.

And those scientists will discover quantum mechanics, discover relativity, discover evolution, discover all the basic principles of science that we understand today, use the best observations they can do, with the best telescopes they will build, and they will derive a picture of the universe which is completely wrong!

They will derive a picture of the universe as being one galaxy surrounded by empty space that is static and eternal... Falsifiable science will produce the wrong answer.

You're accusing Krauss of hubris for this analysis? I think you may have missed his point.

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Spyman seems to think that we should not talk of God. Yet he believes there is a reality, a universe that currently exists beyond our vision, that we should be concerned about, instead.

Tar seems to think that we should not talk of Science. Because he believes there is a God, a supernatural that currently exists beyond our vision, that we should be concerned about, instead.

My question is, "what is the difference between believing in a reality you can not see, and believing in a consciousness you can not see?"

The obvious difference is that we actually can see and measure reality, scientific models make predictions which can be tested against the real world.

At no point is it reasonable to consider that the model in your head is more complete than the thing which you are modeling. That would be a completely inappropriate use of our heads.

At no point does scientists claim superiority over nature, in fact they persistently doubt their models and continuously test them to find flaws.

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Let me see if I understand...

I'll quote what Krauss said and bold the key point:

And it should put us, give us some kind of cosmic humility, which is the other thing that should be characteristic of science.

Humility: The recognition that we don't understand everything. Bill Maher talked about it last night. What pompous assholes like Rick Warren, who claim to understand everything, are antagonistic to science. We should realize that there's more we don't understand about the universe than we do. And I wanna give you an example of this.

The far future. What's gonna happen in the far future? Remeber 100 years ago we thought we lived in a static eternal universe. The amazing thing is for civilizations that live in the far future, what will they see? Well, the universe is accelerating. That means all the distant galaxies are going to be carried away from us and eventually they will move away from us faster than the speed of light. It's allowed in General Relativity.

They will disappear. The longer we wait, the less we will see. In 100 billion years any observers evolving on stars (and there will be stars just like our sun in 100 billion years)... any observers in civilizations evolving around those stars will see nothing except for our galaxy, which is exactly the picture they had in 1915.

All evidence of the Hubble expansion will disappear. Why, because we won't see the other galaxies moving apart from us. So they will have no evidence in fact of the Big Bang. They wont see the Hubble Expansion. They won't even know about dark energy. They wont know about the cosmic microwave background -- it will disappear too. It will red-shift away and it turns out for fancy reasons, this plasma in our galaxy, when the universe is 50 times its present age, the microwave background won't be able to propagate in our galaxy. All evidence of the Big Bang will have disappeared.

And those scientists will discover quantum mechanics, discover relativity, discover evolution, discover all the basic principles of science that we understand today, use the best observations they can do, with the best telescopes they will build, and they will derive a picture of the universe which is completely wrong!

They will derive a picture of the universe as being one galaxy surrounded by empty space that is static and eternal... Falsifiable science will produce the wrong answer.

You're accusing Krauss of hubris for this analysis? I think you may have missed his point.

I'd like to point out for the third time in this thread that indeed Krauss eplanation is a direct result of our current cosmologic model, and that the conclusion that "they will derive a picture of the universe which is completely wrong!" should ring a bell and indicate that we are wrong, and not that we are right and some people in the future will be wrong.

Edited by michel123456
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I'd like to point out for the third time in this thread that indeed Krauss eplanation is a direct result of our current cosmologic model, and that the conclusion that "they will derive a picture of the universe which is completely wrong!" should ring a bell and indicate that we are wrong, and not that we are right and some people in the future will be wrong.

So you're perfectly happy telling everyone that the universe must be eternal and infinitely old based on nothing more than your gut feeling while faulting Krauss for basing his conclusion on all the available scientific evidence?

When you base your conclusions on wish fulfillment then it probably does seem very strange what Krauss is doing. He is basing his conclusions on evidence. It's just the way scientists think. It's a fundamentally different approach.

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I'd like to point out for the third time in this thread that indeed Krauss eplanation is a direct result of our current cosmologic model, and that the conclusion that "they will derive a picture of the universe which is completely wrong!" should ring a bell and indicate that we are wrong, and not that we are right and some people in the future will be wrong.

And for the second time in this thread I'd like to point out that things change. It is not possible for everyone to be right about everything. Information is lost over time. People in the future being wrong about their picture of the universe is no more unreasonable than us being wrong about how life on earth began or what species existed.

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Let me see if I understand...

I'll quote what Krauss said and bold the key point:

You're accusing Krauss of hubris for this analysis? I think you may have missed his point.

Iggy,

You may know that I am an Atheist. I am not arguing for the God of the Bible. Not as such a God has been characterized.

I am trying to point out the similarity between the notion that such a person as Krauss has about the reality of the big scope picture, and the notion that ALL of humanity has, that such a big scope picture is true.

A religious person might talk about life after death, and a scientist would say, that is foolish, there is no mechanism for your consciousness to continue after the organism that houses it, ceases to function. Yet Krauss can put himself in the shoes of a scientist in an unknown but concievable civilization in 850 billion years, and be concerned about whether or not tthey will have the ability to know what we know. That they will be clueless to some grand knowledge that we possess and they will not know the truth of the situation. What is required in this evaluation is that there IS life and consciousness that did exist, does exist, and will exist OUTSIDE ones individual consciousnness. A situation that interestingly points out, that we know and care about this greater scope thing, that dwarfs our individual lives, our nation's life, our species life, our planet's life, and perhaps our Sun's life. And that we are in possession of this association with the greater scope, have a responsibility to it, and are completely in and of it. All the talking points of every major religion that I can think of.

And as Michel12345 points out, we may well not be in possession of ALL the information required for US to not be wrong about the complete truth the universe knows.

Regards, TAR2

And by all accounts, the universe has not yet done what it is going to do next. And there is a lot of time for the universe to do many things, between now and 840billion years from now. 100 years ago, the Earth did not have the internet. There was not such a global consciousness as we currently possess. Instant sharing of thoughts and facts. I could die tomorrow, and life will go on. There IS life after death. Consciousness greater than a single human consciousness. It is not a pretend God I am arguing for. Its the real thing.

That Krauss holds the only key, is as silly and as true as the notion that Jesus holds it.

And what the scientists in that civilization 850billion years from now will know about, is all the stuff that has not happened yet. They will have certain access to 840billion years worth of stuff that for us, and any currently existing organism, has not yet occurred. In essence, they will know much much more than us.

And my guess is, that if all they will have to work with is wavelengths of light the length of a galaxy, they would have evolved to sense such.

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I'm afraid that didn't make sense to me. A small example,

You may know that I am an Atheist... It is not a pretend God I am arguing for. Its the real thing.

I can't make sense of that. I don't think expounding on it would help.

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Tar seems to be to focused on burning Krauss for some personal reason, that he is beyond reading and understanding any explanations.

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Spyman,

I don't know Krauss. Just saw the video, and know he has a book to sell.

I am viewing him as a proxy for people who believe their model of the universe is as good as, or superior to, the universe itself. I think this to be a delusion of sorts. Not unlike one taking an image of God, an imaginary friend, whose modeled characteristics, are thought to actually exist in reality, as they exist in ones head.

What has struck me, often in my attempts to understand space time diagrams, and various cosmic concepts of proper time and such, is that what works in my mind, in terms of analogies and transforms and shifts of scale and positions and grain size, do not have to work in reality. And in most all cases, can not take all the real aspects of reality, into consideration. Like the ants on the rubberband, the model does not do the real thing any justice, and one is likely to not consider the problem correctly, attempting to simplify something that is just not simplifyable.

The major drawback in considering the universe as one thing, containable in ones mathematical model of it, is that the model must be considered as something that exists at once, where the universe does not operate in this fashion.

Consider the photons of light emitted from Alpha Centurie, last year, that are hitting our eyes today, when we look up at her (assuming we are in a position on Earth that would see her shine at night). When were those photons emitted? Do the other photons, emitted at that moment still exist? Currently? Of course, they have to exist, expanding in the spherical shell, in the same fashion as the light of my match. Each moment of Alpha's shining. Every moment of Alpha's shining, currently exists somewhere in the universe. From the very first time Alpha shined, til now. We do not have the facilities in our heads, even with all the billions of cells and synapses and arrangements of signals to model that properly. Because it is not all happening at once. There is not a viewpoint available that can see everywhere where Alpha's photons currently are. And every location in space, within a billion light years, (or however many billion years Alpha has been shining) has to be, currently experiencing photons, from Alpha Centuri.

This condition, is not approachable by considering one event at a time. Because each event exists for an eternity, afterward, at increasing distances and later times. It is not a once and done situation. Only here and now, is once and done. The whole universe operates on a different principle.

Regards, TAR2

I'm afraid that didn't make sense to me. A small example,

I can't make sense of that. I don't think expounding on it would help.

Iggy,

There are consciousnesses other than me. I don't know all of them, but I imagine they are true. And there are organizations, where people have gotten together to form greater entities, by mutual plan, purpose and effort.

These are real things, that exist, that are greater than any particular single consciousness. And each particular single consciousness, brings to the table a long history of evolution and capabilities. Each of us is all of that which came before. Not a one of us, sprang into existence of our own volition. We are beholding to nature and we are beholding to the efforts of other conscious humans, for our existance. And the universe that we are in and of is vastly superior to anything we can manage, even when we are a million strong, working on the same plan.

So there is a real "being" that we are in and of. It has all the strengths and weaknesses, capabilities and drawbacks, that we possess. We have no other source to consider, no other venue within to operate, and no other place to go. Any power and source that does not make sense, that is not evident, that is magical and impossible in nature is not true. That still leaves everything which is evident, does make sense, and is known by all of us, to be true. Which is a substantially huge and intricate, wonderfully incomprehensible body of stuff. This body of stuff is the real God, all the things which are true.

Regards, TAR2

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I am viewing him as a proxy for people who believe their model of the universe is as good as, or superior to, the universe itself.

This is why it appears to some you have a personal vendetta against Krauss. Please point out where Krauss says or implies his model of the universe is superior to the universe itself (although I have to admit I am uncertain how a model of a thing can be 'superior' to the thing itself).

How do you reconcile your view with his statement that "We should realize that there's more we don't understand about the universe than we do."? To suggest that simply describing what he believes the future to hold means he somehow thinks his model is 'superior', does indeed make it appear that you are grasping at straws to criticize him.

Edited by zapatos
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zapatos,

I suppose where I understand there is no personal vendetta at work, is that I am criticizing myself, or warning myself, against considering my own personal model in any way special or superior to the model of the universe others hold.

Anything I attempt to put together about the universe is based exactly on the measurements and observations and mathematical models that others, smarter and more hardworking than myself, have discovered, or noticed, or deduced about our universe. That, based together with my own obsevations, and my own deductions about what has to be the case. There is no super huge white bearded magical pixie moving stuff about, and answering prayers. That is not what I am arguing for the existence of. I am merely raising the point that ANY concern we might have of the view scientists will have of the universe, from the station of the Milky Way, in half a trillion years, is rather indicative, of the belief in life after death...WAY after death. And it is assuming that such scientists will be operatiing in similar fashion to how humans operate, with the same constraints, the same abilities, the same time and size scale, and the same basic way of looking at the universe, that human's have. If one is to take an objective view, such as this, and one that does not even require human Earthlings to even be involved, one is taking a Godlike stance, that would indicate belief in the existence of, and the importance of, things that will never even come close to having anything to do with an Earthling. That Krauss can care about such a view, which has no way to be verified, or observed, by anybody, but the hypothetical scientist, of his own construction, is as completely removed from anything real, as can possibly be. And to consider he is RIGHT about it, has just about as much validity or purpose, or value, as considering that the Earth is balanced on the back of a Turtle.

Suppose he is right? Should we be scared of the dark? I say no. There is plently of universe to see, for us, as long as we live. He is concerned over absolutely nothing real. If we are to go on flights of fancy, given half a trillion years, there could also be the possibiliy that consciousness the size of star systems could develop, and they could have memories that last a billion years, and they may have the patience of an Ent, or more, and be able to wait for a signal the wavelength of a universe to arrive. They might truely consider the Galaxy next door as being currently existant and be able to interact with it, over their vast lifetime, and a distance of 400,000 ly might be considered to these "scientists", just a heartbeat away. We do not know their size and scale and memory ability, and what they will consider a moment.

It is sure to be different than a human's size and scale and three second moment. Why make any assumptions at all, about what they will be able to know about, constraining them to the models held in the minds of human Earthlings, when the universe was just a babe, only 13.7 billion years old?

Regards, TAR2

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zapatos,

I suppose where I understand there is no personal vendetta at work, is that I am criticizing myself, or warning myself, against considering my own personal model in any way special or superior to the model of the universe others hold.

Anything I attempt to put together about the universe is based exactly on the measurements and observations and mathematical models that others, smarter and more hardworking than myself, have discovered, or noticed, or deduced about our universe. That, based together with my own obsevations, and my own deductions about what has to be the case. There is no super huge white bearded magical pixie moving stuff about, and answering prayers. That is not what I am arguing for the existence of. I am merely raising the point that ANY concern we might have of the view scientists will have of the universe, from the station of the Milky Way, in half a trillion years, is rather indicative, of the belief in life after death...WAY after death. And it is assuming that such scientists will be operatiing in similar fashion to how humans operate, with the same constraints, the same abilities, the same time and size scale, and the same basic way of looking at the universe, that human's have. If one is to take an objective view, such as this, and one that does not even require human Earthlings to even be involved, one is taking a Godlike stance, that would indicate belief in the existence of, and the importance of, things that will never even come close to having anything to do with an Earthling. That Krauss can care about such a view, which has no way to be verified, or observed, by anybody, but the hypothetical scientist, of his own construction, is as completely removed from anything real, as can possibly be. And to consider he is RIGHT about it, has just about as much validity or purpose, or value, as considering that the Earth is balanced on the back of a Turtle.

Suppose he is right? Should we be scared of the dark? I say no. There is plently of universe to see, for us, as long as we live. He is concerned over absolutely nothing real. If we are to go on flights of fancy, given half a trillion years, there could also be the possibiliy that consciousness the size of star systems could develop, and they could have memories that last a billion years, and they may have the patience of an Ent, or more, and be able to wait for a signal the wavelength of a galaxy to arrive. They might truely consider the Galaxy next door as being currently existant and be able to interact with it, over their vast lifetime, and a distance of 400,000 ly might be considered to these "scientists", just a heartbeat away. We do not know their size and scale and memory ability, and what they will consider a moment.

It is sure to be different than a human's size and scale and three second moment. Why make any assumptions at all, about what they will be able to know about, constraining them to the models held in the minds of human Earthlings, when the universe was just a babe, only 13.7 billion years old?

Regards, TAR2

Edited by tar
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There's not enough information to determine with much certainty that the universe will end in any particular way, or at all, there's just too many unknowns, we don't really even have physical evidence of dark energy.

Edited by EquisDeXD

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