Cosmological Crisis - Flat or Round?

[pantheory]

1 hour ago, WalterP said:

On Tuesday, I wrote this.

 

The simple answer to the question, Is the universe Closed, Flat or Open? is that it's too soon to say for sure.

Our observable universe is simply too small a volume of space for us to say for sure, as of today.  It's possible that future observations may pin the answer down, but as far as I'm concerned, the jury's still out.  I tend to take what the NewsScientist says with a pinch of salt.  They have something of a reputation for sensationalizing issues and over-simplifying complex topics.   

 

Today, after skimming over articles on various science forums I noticed this.

 

 https://arxiv.org/pdf/1903.12097.pdf

 

It's extremely technical and I can't claim to understand much of it, but this section is relevant to this thread.

 

Our measurements support a value of H0 that is closer to that one found by the BAO methodology rather than the higher value from the Cepheids. Interestingly, the 8 H0−Ωm contours from γ-ray attenuation are roughly orthogonal to results from other techniques, which makes our results nicely complementary to those from other probes. In order to improve the H0 measurement we need to measure optical depths up to the largest possible energies. This is difficult with LAT because of the limited photon statistics. However, it may be possible with the future Cherenkov Telescope Array (CTA, Hinton et al. 2019). 

 

In a nutshell, this paper seems to be supporting the Flat universe of the LCDM Concordance Model.  Please note that I do not necessarily support any particular cosmological model, so all I am pointing out here is what I said on Tuesday - the jury's still out. If different measurements appear to be coming to different conclusions about the geometry of the universe, then the issue is still in a state of flux and further, better measurements are needed to settle things.

 

Thank you.

 

Walter.

 

Hi Walter,

 

I looked at your link and found it very interesting. Although some have asserted that there are ties between the Hubble constant dispute and the flat vs. curved universe dispute, I think such arguments are weak. As to your link, I found it very interesting because in my own research and related paper I also came up with the same Hubble constant of z = 68, with a large tolerance range of z ~ 8.4. The basis for this rate of expansion was type 1a supernova data up to 2014, all based upon the Hubble distance formula. Although I never believed in an expanding universe (I have a non-conventional explanation for redshifts), through many years of research and a related paper I derived a different formula to calculate cosmic distances based upon type 1a supernova data, stating that the Hubble distance formula is wrong and therefore the Hubble constant is a myth. The Hubble formula was derived from the Lorentz equations (the same as Special Relativity) based upon an expanding universe. If the universe is not expanding then this distance formula is wrong and there would be no Hubble constant. Instead it would be more like a Hubble variable.

 

Recently a research associate of mine wrote a book about this subject putting me as lead author with my permission, and putting one of my peer-reviewed, published and cited papers in the middle of the book. If you would like to see the link to the paper, the book cover and information and quotes from the book please PM me and I will send them to you.

[Joshpantera]

4 hours ago, WalterP said:

On Tuesday, I wrote this.

 

The simple answer to the question, Is the universe Closed, Flat or Open? is that it's too soon to say for sure.

Our observable universe is simply too small a volume of space for us to say for sure, as of today.  It's possible that future observations may pin the answer down, but as far as I'm concerned, the jury's still out.  I tend to take what the NewsScientist says with a pinch of salt.  They have something of a reputation for sensationalizing issues and over-simplifying complex topics.   

 

Today, after skimming over articles on various science forums I noticed this.

 

 https://arxiv.org/pdf/1903.12097.pdf

 

It's extremely technical and I can't claim to understand much of it, but this section is relevant to this thread.

 

Our measurements support a value of H0 that is closer to that one found by the BAO methodology rather than the higher value from the Cepheids. Interestingly, the 8 H0−Ωm contours from γ-ray attenuation are roughly orthogonal to results from other techniques, which makes our results nicely complementary to those from other probes. In order to improve the H0 measurement we need to measure optical depths up to the largest possible energies. This is difficult with LAT because of the limited photon statistics. However, it may be possible with the future Cherenkov Telescope Array (CTA, Hinton et al. 2019). 

 

In a nutshell, this paper seems to be supporting the Flat universe of the LCDM Concordance Model.  Please note that I do not necessarily support any particular cosmological model, so all I am pointing out here is what I said on Tuesday - the jury's still out. If different measurements appear to be coming to different conclusions about the geometry of the universe, then the issue is still in a state of flux and further, better measurements are needed to settle things.

 

Thank you.

 

Walter.

 

It seems that the OP article is conflating universe with space. Isn't it space which has been observed to be flat? Because space could be flat, infinite and eternal and extend out forever. But a universe is merely some observable region within the context of space. If there's no hard boundary, then it doesn't seem to make very much sense to see a universe as anything more than a larger sized region of star systems in space. Such as the level beyond super clusters of galaxies within the context of a flat space. 

 

I'm trying to visualize this issue. 

[WalterP]

4 hours ago, pantheory said:

 

Hi Walter,

 

I looked at your link and found it very interesting. Although some have asserted that there are ties between the Hubble constant dispute and the flat vs. curved universe dispute, I think such arguments are weak. As to your link, I found it very interesting because in my own research and related paper I also came up with the same Hubble constant of z = 68, with a large tolerance range of z ~ 8.4. The basis for this rate of expansion was type 1a supernova data up to 2014, all based upon the Hubble distance formula. Although I never believed in an expanding universe (I have a non-conventional explanation for redshifts), through many years of research and a related paper I derived a different formula to calculate cosmic distances based upon type 1a supernova data, stating that the Hubble distance formula is wrong and therefore the Hubble constant is a myth. The Hubble formula was derived from the Lorentz equations (the same as Special Relativity) based upon an expanding universe. If the universe is not expanding then this distance formula is wrong and there would be no Hubble constant. Instead it would be more like a Hubble variable.

 

Recently a research associate of mine wrote a book about this subject putting me as lead author with my permission, and putting one of my peer-reviewed, published and cited papers in the middle of the book. If you would like to see the link to the paper, the book cover and information and quotes from the book please PM me and I will send them to you.

 

That's a kind offer Pantheory, but with all due respect, I must decline.

 

My take on the current 'issues' in cosmology is that we will soon(ish) be in possession of data that will resolve them or perhaps overturn the current paradigm.  As you  know, I'm not wed to any particular theory, model or paradigm and so it's not a big deal for me to wait and see what pans out.  It's my view that the current cosmic distance ladder has too many rungs that are poorly constrained by the data.  A good reappraisal of the lowest rungs will come some time after 2021, when the last Gaia data is released.

 

https://www.cosmos.esa.int/web/gaia/release

 

I'm of the opinion that, together with such advances as the JWST, the EELT and the LSST, the Gaia data will bring a sea change in our understanding of the cosmos.  To be honest, I can't deny that I'm eagerly awaiting the mid 2020's. 

 

Thanks again.

 

Walter.

[WalterP]

1 hour ago, Joshpantera said:

 

It seems that the OP article is conflating universe with space. Isn't it space which has been observed to be flat? Because space could be flat, infinite and eternal and extend out forever. But a universe is merely some observable region within the context of space. If there's no hard boundary, then it doesn't seem to make very much sense to see a universe as anything more than a larger sized region of star systems in space. Such as the level beyond super clusters of galaxies within the context of a flat space. 

 

I'm trying to visualize this issue. 

 

Hello Josh.

 

I appreciate your confusion and I agree that these are not easy concepts to visualize.  As it happens, in the next step in the Failed Cosmology of WLC thread I was going to explain the apparent contradiction between what appear to be two very different things.  The observed flatness of space and accelerating 'opening out' of space by the cosmological constant (CC).  If you recall, early on in the thread I said that we would be covering what the CC is and how it is measured.    

 

1.  What is the Cosmological Constant?

2.  How is it measured?

3.  Why did Hawking and Penrose make these four assumptions in the first place?

 

So far we've haven't tackled these three points out of their given order.  We've covered 3, with the opacity of the CMB forcing Hawking and Penrose to make assumptions.  I posted info on the CC on Tuesday, so that's the start of us covering point 1.  Once you and Disillusioned are happy to move on to point 2, then we can cover how the CC is measured.  When we get there I can more readily explain some of the things you mentioned above.  Is that ok?

 

 

One thing I can do here and now is help with this.  "But a universe is merely some observable region within the context of space."

 

https://en.wikipedia.org/wiki/Observable_universe  The term 'observable universe' is used to apply to any region of space that any observer can see.

https://en.wikipedia.org/wiki/Universe The term 'universe' is used to apply to everything that exists, regardless of what any observers can see.

 

Josh, the former is knowable by us because it is simply the limit of how far we can see.  Whereas, the latter is unknown to us.  As I'm sure you're aware, almost all cosmology proceeds by assumption and inference and not by direct observation.  The speed of light sees to that.  Therefore, we assume and infer that space extends beyond the limit of our visual horizon.  The name we give to the observable universe and the space beyond that limit is 'the universe'.  The name we give the space within that limit is the 'observable universe'.  The two should never really be conflated or swapped over.  Doing that causes misunderstanding and confusion.

 

Space within the observable universe has been measured to be flat.  But, as I've shown in this thread, the wider universe beyond our horizon might be Flat, Closed or Open.  We just don't know for sure.  Science papers like the ones cited in this thread are all trying to discover if clues within the observable universe can tell us about the flatness or curvature of the entire universe.  My stated position is that we need much better data before we are in a position to find an answer.  

 

If you look again at the sequence of graphics I posted you can see that an entire universe can start off as a quantum-sized hypersphere that inflates to become so vast that it looks flat to any observer within it.  Those last words deserve repeating.  A sufficiently-large hyperspherical universe looks FLAT TO ANY OBSERVER WITHIN IT.   That's all my graphics can show.  No more.  

 

But the graphic you posted shows an ensemble of separate hyperspherical universes from GOD'S point of view.  From a position 'outside' (?) of 'anywhere' (?) in space and time.  None of us can ever aspire to see reality from such a viewpoint.  You see how I'm even struggling to find the right words to use?  Such images, even if they are based upon peer-reviewed science papers, are at their best, no more than educated guesses and at their worst, unbridled speculation.  I can make an educated guess if you'd like me to, but I wont indulge in unbridled speculation about things we can never observe.    

 

To recap, I'll explain about the measured flatness of the observable universe and how that relates to the entire universe in the Failed Cosmology thread.  

 

I hope this post has been of some help.

 

Thank you.

 

Walter.

 

 

[Joshpantera]

On 11/10/2019 at 7:26 PM, WalterP said:

Space within the observable universe has been measured to be flat.  But, as I've shown in this thread, the wider universe beyond our horizon might be Flat, Closed or Open.  We just don't know for sure.  Science papers like the ones cited in this thread are all trying to discover if clues within the observable universe can tell us about the flatness or curvature of the entire universe.  My stated position is that we need much better data before we are in a position to find an answer.  

 

That's where the article is conflated "space" with "universe." It reads over and over that the universe is measured to be flat. Technically it's space within the observable universe and they aren't making that clear. 

 

On 11/10/2019 at 7:26 PM, WalterP said:

But a universe is merely some observable region within the context of space. If there's no hard boundary, then it doesn't seem to make very much sense to see a universe as anything more than a larger sized region of star systems in space. Such as the level beyond super clusters of galaxies within the context of a flat space. 

 

 

By "a universe," I'm referring to the notion that there could be multiple universes and not just one. In a given universe, of multiple universes, I want to narrow down the roll of "space" within the context of a multiverse of many different universes. So this relates to the observable and entire universe in this way.

 

Is the entire universe merely "space," unbound? And the observable universe the one universe of many other universes, each other universe being observable regions space available to a fixed observer? Or are you saying that each individual universe is made up of multiple "entire universes," of huge magnitude, each universe being large beyond observation and multiple in number? 

 

Multiverse of individual observable universes? 

 

Multiverse of individual entire universes? 

 

 

[WalterP]

10 hours ago, Joshpantera said:

 

By "a universe," I'm referring to the notion that there could be multiple universes and not just one. In a given universe, of multiple universes, I want to narrow down the roll of "space" within the context of a multiverse of many different universes. So this relates to the observable and entire universe in this way.

 

Is the entire universe merely "space," unbound? And the observable universe the one universe of many other universes, each other universe being observable regions space available to a fixed observer? Or are you saying that each individual universe is made up of multiple "entire universes," of huge magnitude, each universe being large beyond observation and multiple in number? 

 

Multiverse of individual observable universes? 

 

Multiverse of individual entire universes? 

 

 

 

Josh,

 

As far as I know there are no agreed or properly defined answers to you questions.  That's because the one thing that could help us define and agree is denied to us.  Evidence.  We have no evidence, no observations, no data and no measurements to verify or falsify anything to do with what lies beyond our observable universe.  Therefore, whatever is theorized about what lies 'out there' cannot be defined or agreed upon.

 

This is why the multiverse models proposed by Max Tegmark are just as valid or invalid as those proposed by Alan Guth, Andrei Linde, Sean Carroll or Neil Turok.  Nobody knows!  

 

Even the nomenclature used by different scientists can be different and nobody can gainsay anyone else.  For example, Lee Smolin's Fecund Universe hypothesis posits the creation of new universes from black hole singularities, leading to what is a multiverse in all but name.  Yet Smolin is adamant that there is only one universe, albeit one consisting of myriads of  sub-universes, each one 'budding' off earlier ones.  It's Smolin's personal choice to assert that there is only one universe and even though other scientists can disagree with the way he uses that word, nobody can appeal to any observations or evidence to call him to account.

 

Do you see where this leaves you in your quest for definitions and answers about the multiverse?

 

 

 

I'm sorry, but while there's plenty of theories and speculation, there's nothing concrete to guide you. 

 

Thank you.

 

Walter.

[Joshpantera]

Regardless of the model or conceptualization, don't they all have in common the need for space to extend beyond the observable universe in some way. That should be within the range of an answerable question.

 

If any do not, why? And what do they propose, if not an unbound space? 

[WalterP]

12 hours ago, Joshpantera said:

Regardless of the model or conceptualization, don't they all have in common the need for space to extend beyond the observable universe in some way. That should be within the range of an answerable question.

 

If any do not, why? And what do they propose, if not an unbound space? 

 

Josh,

 

If you recall this graphic, I explained that it shows how we cannot tell the geometry of the entire universe, from looking at the curvature of space within the observable universe.  We could be in a Closed, Flat or Open universe, but the full extent of our entire universe is so vast that all three kinds will look flat to us.

 

Therefore, if the curvature is unknowable, so is the true extent.  That's all that I can reasonably say without venturing into speculation.

 

Ok Josh, you seem to want to know more about how each separate universe in the multiversal ensemble of universes relates to the others?  Is that about right?  If so, then I can acquaint you with what I know about Andrei Linde's Chaotic Eternal Inflation model, but only if it's understood that I consider it to be speculation.  Please do not conclude that what I'm about to explain is in any way right, correct, factual or true.  Nor do I support, agree with or promote it.  Are we clear on both points?  

 

 

This graphic dates from the 80's or 90's and was used by Linde to illustrate his model in an easily understood way.  It's not an actual representation of what the multiverse looks like.  A scalar energy field is represented by a flat, square multi-coloured plane and this evolves in a chaotic way.

 

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.246.4976&rep=rep1&type=pdf

 

If you scroll down to page 18 of this .pdf presentation you will find four images that show a scalar field evolving over time.  Here is what Linde has written about the scalar field.

 

Figure 2: Evolution of scalar fields φ and Φ during the process of self-reproduction of the universe.

The height of the distribution shows the value of the field φ which drives inflation. The surface is painted red, green or blue corresponding to three different minima of the potential of the field Φ. Laws of low-energy physics are different in the regions of different color. The peaks of the “mountains” correspond to places where quantum fluctuations bring the scalar fields back to the Planck density. Each of such places in a certain sense can be considered as a beginning of a new Big Bang. At the end of inflation, each such part becomes exponentially large. The universe becomes a multiverse, a huge eternally growing fractal consisting of different exponentially large locally homogeneous parts with different laws of low-energy physics operating in each of them.

 

So, the tip of each mountain peak represents the site where a new Big Bang takes and a new universe is 'born'.  The given colour and height of the peak denotes what kind of physical laws hold good in that particular universe.  Each of these universes becomes exponentially large.  Which means that anyone inhabiting them will be in the same situation as we are, unable to tell if their particular universe is Closed, Flat or Open.  It also means that just as we see our universe as being 'locally' homogeneous, so will everyone else. 

 

Nobody will be able to know anything about what is happening in the scalar field that 'birthed' their universe, nor about anything that is happening on other peaks or in other universes that have been 'birthed' by other peaks.  Each universe is entirely separate from each other.

 

Now for a question.

 

Josh, you'll see that Linde doesn't actually show any new Big Bangs happening, doesn't show any new universes emerging from the tips of the peaks and doesn't show these universes becoming exponentially large.

 

Why do you think that is?

 

Thank you.

 

Walter.

 

 

 

 

[WalterP]

Now for a question.

 

Josh, you'll see that Linde doesn't actually show any new Big Bangs happening, doesn't show any new universes emerging from the tips of the peaks and doesn't show these universes becoming exponentially large.

 

Why do you think that is?

 

Thank you.

 

Walter.

 

(Just in case you missed this, Josh.)

[Joshpantera]

6 hours ago, WalterP said:

Now for a question.

 

Josh, you'll see that Linde doesn't actually show any new Big Bangs happening, doesn't show any new universes emerging from the tips of the peaks and doesn't show these universes becoming exponentially large.

 

Why do you think that is?

 

Thank you.

 

Walter.

 

(Just in case you missed this, Josh.)

 

Because it's a finite conceptualization? 

[WalterP]

29 minutes ago, Joshpantera said:

 

Because it's a finite conceptualization? 

 

Yes.  That's quite true.  But there's also the limitation of what can be shown on a flat computer screen.

 

The flat, square multi-coloured plane that Linde uses to show the evolution of the energy field is a compressed view of a 4 dimensional volume of space, so it's already not a true representation at all.  More like a flat map of a 3 dimensional landscape, with an extra dimension still hidden, one that we cannot see.  Each peak terminates in a new universe, but these are also 4 dimensional hyperspheres too, so not only can they not be properly shown on a flat screen, but our visual cortex's can only interpret them as spheres, 3 dimensional objects.

 

Any way you cut this, our computers and our brains simply aren't up to the job of visualizing what's actually going on here.  That's the frustrating part of not being able to do the math.  Those that can are able to calculate what 4 dimensional spaces are, even if they can't visualize them.

 

Whenever I see a diagram that uses a sphere to say something about the cosmos Josh, I make sure to check if it's really a sphere or if it's a sphere that's meant to be a hypersphere.  If it's the latter, I just accept that I'll never be able to visualize it properly.  C'est la vie!

 

Thank you.

 

Walter.