Ah! I should straighten the Wick first. Here goes nuthin...

I have to leave anyway to watch the Tata Steel chess competition (very strong field inc. Hou Yifan & Magnus Carlsen, amongst others) - brb to catch up...

newolder wrote:I recall it has something to do with an extra dimension to space and I've asked in the past (unless I'm mis-remembering) how it differs from the Randall Sundrum model of 1999. Here's a quote from a recent essay on dimensions that may prove useful as a catch-up:

...
In 1999, Lisa Randall (the first woman to get tenure at Harvard as a theoretical physicist) and Raman Sundrum (an Indian-American particle theorist) proposed that there might be an additional dimension on the cosmological scale, the scale described by general relativity. According to their ‘brane’ theory – ‘brane’ being short for ‘membrane’ – what we normally call our Universe might be embedded in a vastly bigger five-dimensional space, a kind of super-universe. Within this super-space, ours might be just one of a whole array of co-existing universes, each a separate 4D bubble within a wider arena of 5D space.
...

From Margaret Wertheim at aeon.

I admit that, when put this way, there isn't that much difference between this and my cosmology. What puts me off is that big bangs are supposed to be the result of collisions between these branes, rather than (as I think) the aftermath of the collapse of a massive body, just as forms a black hole in this universe.

DavidMcC wrote:rather than (as I think) the aftermath of the collapse of a massive body, just as forms a black hole in this universe.

The collapse of a massive body forming a black hole is a very attractive proposition.

However, thet mass is still present in our cosmos, as can be demonstrated by observing objects in our cosmos orbiting around black holes. This is attractive indeed.

DavidMcC wrote:...
I admit that, when put this way, there isn't that much difference between this and my cosmology. What puts me off is that big bangs are supposed to be the result of collisions between these branes, rather than (as I think) the aftermath of the collapse of a massive body, just as forms a black hole in this universe.

Where does the matter for the “massive body” originate, in your idea? The colliding branes in ekpyrotic S&T et al are matter free.

Cito di Pense wrote:

DavidMcC wrote:rather than (as I think) the aftermath of the collapse of a massive body, just as forms a black hole in this universe.

The collapse of a massive body forming a black hole is a very attractive proposition.

However, thet mass is still present in our cosmos, as can be demonstrated by observing objects in our cosmos orbiting around black holes. This is attractive indeed.

The mass is still there, as a form of dark matter (or very dark matter, if you prefer!) in our universe (or whichever is the parent to the BH). Thus, we are living inside a very big black hole (or at least in the space created by it's formation).

Like the pun on "very attractive". It fits your style.

newolder wrote:

DavidMcC wrote:...
I admit that, when put this way, there isn't that much difference between this and my cosmology. What puts me off is that big bangs are supposed to be the result of collisions between these branes, rather than (as I think) the aftermath of the collapse of a massive body, just as forms a black hole in this universe.

Where does the matter for the “massive body” originate, in your idea? The colliding branes in ekpyrotic S&T et al are matter free.

In loop quantum gravity, matter as observed in a given universe) is an excited state of space in that universe, and is formed when the space is formed. Thus, this appears to be a point of divergence between my (Smolin-inspired) cosmology and ekpyrotic cosmology.

DavidMcC wrote:...
In loop quantum gravity, matter as observed in a given universe) is an excited state of space in that universe, and is formed when the space is formed. Thus, this appears to be a point of divergence between my (Smolin-inspired) cosmology and ekpyrotic cosmology.

Do you have a source for that interesting claim? From the loop quantum gravity wikipedia section, "Gravitons, string theory, supersymmetry, extra dimensions in LQG":

Loop Quantum Gravity has nothing to say about the matter(fermions) in the universe.

So, is there somewhere we can find an explicit statement of what this cosmology is and what its predictions are?

newolder wrote:

DavidMcC wrote:...
In loop quantum gravity, matter as observed in a given universe) is an excited state of space in that universe, and is formed when the space is formed. Thus, this appears to be a point of divergence between my (Smolin-inspired) cosmology and ekpyrotic cosmology.

Do you have a source for that interesting claim? From the loop quantum gravity wikipedia section, "Gravitons, string theory, supersymmetry, extra dimensions in LQG":

Loop Quantum Gravity has nothing to say about the matter(fermions) in the universe.

You need to read Lee Smolin on quantum loop gravity, not wikipedia, which is not good on this particular subject. There is no basis to assume gravitons per se exist. Also the brane theory is not obviously correct, based as it is on two mathematicians being stuck in a traffic jam, on their way to a conference, I believe!

This site is once again becoming an embarrassment to a rationalist scientist like me.

DavidMcC wrote:...
You need to read Lee Smolin on quantum loop gravity, not wikipedia, which is not good on this particular subject. ...

If it is difficult to attribute and quote the relevant section(s), I'll pass, thanks.

newolder wrote:

DavidMcC wrote:...
You need to read Lee Smolin on quantum loop gravity, not wikipedia, which is not good on this particular subject. ...

If it is difficult to attribute and quote the relevant section(s), I'll pass, thanks.

I'm not asking you to do that, just find what he wrote about LQG, up to the point when he declared that he must be wrong, but for spurious reasons (relating to the number of generations of universes being assumed (incorrectly, IMO) to be so large that there would be some kind of natural selection acting on them, by analogy with biological NS (which, of course DOES involve a very large number of generations).

So, where are we up to? It doesn't seem that a direct statement of the hypothesis will be forthcoming, but what I can see so far is:

• This cosmology is essentially a brane cosmology, but without branes.
• Collapsing black holes (in a higher dimension?) represent big bang events.
• The cosmology does not admit a mathematical description.

At least two questions occur to me:
(i) What predictions does this hypothesis make?
(ii) How are those predictions derived from the hypothesis?

Edit: typo

LucidFlight wrote:

DavidMcC wrote:... Science is not served well by arguing on the basis that "the great and the good" know best. It is served by science-based challenges to the established views. Havinf said that, I was not posting my cosmology merely to be different, but because I believe it is a better cosmology than the rest.

Have you had your cosmology published and peer reviewed?

No. LF, I haven't. Partly because I do not want to go to so much trouble and expense, as I am retired, and wasn't a professional cosmologist even before I retired. I thought it was best to post it first on the original Richard Dawkins site, then here, quite a few years ago. Back then, it didn't generate the bizarre conversations that it has in recent days.

DavidMcC wrote:

newolder wrote:

DavidMcC wrote:...
You need to read Lee Smolin on quantum loop gravity, not wikipedia, which is not good on this particular subject. ...

If it is difficult to attribute and quote the relevant section(s), I'll pass, thanks.

I'm not asking you to do that,

That's the first correct thing you've posted.
However, I am asking you to find, post and attribute the relevant info.

just find what he wrote about LQG, up to the point when he declared that he must be wrong, but for spurious reasons (relating to the number of generations of universes being assumed (incorrectly, IMO) to be so large that there would be some kind of natural selection acting on them, by analogy with biological NS (which, of course DOES involve a very large number of generations).

Bracketting error, logic fail, bait and switch - all noted.

Why are you ignoring Thommo's posts in this topic?

DavidMcC wrote:

LucidFlight wrote:

DavidMcC wrote:... Science is not served well by arguing on the basis that "the great and the good" know best. It is served by science-based challenges to the established views. Havinf said that, I was not posting my cosmology merely to be different, but because I believe it is a better cosmology than the rest.

Have you had your cosmology published and peer reviewed?

No. LF, I haven't. Partly because I do not want to go to so much trouble and expense, as I am retired, and wasn't a professional cosmologist even before I retired. I thought it was best to post it first on the original Richard Dawkins site, then here, quite a few years ago. Back then, it didn't generate the bizarre conversations that it has in recent days.

Ah, fair enough. That's understandable.

Yes, I see you posted this:
http://www.rationalskepticism.org/post1 ... l#p1211883

Very interesting reading. Certainly worth revisiting by many of the posters here.

LucidFlight wrote:Ah, fair enough. That's understandable.

Yes, I see you posted this:
http://www.rationalskepticism.org/post1 ... l#p1211883

Very interesting reading. Certainly worth revisiting by many of the posters here.

That's great, thanks for finding that, I'll give it a look later.

Edit: Well, I've read it, and it is far more coherent than I expected. I'm not sure it's sufficiently well quantified to really even discuss whether there are reasons to think it's right, but nonetheless it does start to clear up what David's driving at here.

It may also provide a clue as to what the "logical inconsistencies" David attributes to Hawking are supposed to be:

It is important to realise that this cosmology makes a black hole (BH) synonymous with a universe (even though it might not make a very interesting one, if it does not have enough energy to make BHs of its own). I therefore reject Hawking's argument that clocks stop as they approach the event horizon of a black hole. As I thought was well known, they only appear to do so to an observer watching them from outside the BH's event horizon, relying on photons from the clock. If you were travelling with the clock, time would not seem to stop, and the clock would get to cross the event horizon. If it did not, a black hole could not grow, and everything it "feeds" on would be forever orbiting it, never falling in. Thus, the "stopping" is observer frame-dependent Unfortunately, Hawking appears, in one of his TV programs, to tie his atheism to this clock-stopping idea.

So, great find LF, thank you.

Thommo wrote:So, where are we up to? It doesn't seem that a direct statement of the hypothesis will be forthcoming,

That's because I stated it in detail years ago, on this site (pp 6&7 in the LQG thread in he Physics forum).

...but what I can see so far is:

• This cosmology is essentially a brane cosmology, but without branes.
• Collapsing black holes (in a higher dimension?) represent big bang events.

Yes, but I refer to the higher dimensions as "mother universes", because it is a more appropriate term to my hyposthesis.

The cosmology does not admit a mathematical description.

At least two questions occur to me:
(i) What predictions does this hypothesis make?
(ii) How are those predictions derived from the hypothesis?

Edit: typo

I admit that its potential predictions have already been observed (and are therefore what I called "postdictions"). Sorry about that, but at least it is possible that someone would come up with new predictions on its basis -indeed, that is one reason why I posted it in the first place. Of course that would requre that someone actually reads it! On the other hand, some of the observations I based it on could be considered superfluous to the hypothesis, and might have been predictions had I been in time.

Thommo wrote:

LucidFlight wrote:Ah, fair enough. That's understandable.

Yes, I see you posted this:
http://www.rationalskepticism.org/post1 ... l#p1211883

Very interesting reading. Certainly worth revisiting by many of the posters here.

That's great, thanks for finding that, I'll give it a look later.

Edit: Well, I've read it, and it is far more coherent than I expected. I'm not sure it's sufficiently well quantified to really even discuss whether there are reasons to think it's right, but nonetheless it does start to clear up what David's driving at here.

It may also provide a clue as to what the "logical inconsistencies" David attributes to Hawking are supposed to be:

It is important to realise that this cosmology makes a black hole (BH) synonymous with a universe (even though it might not make a very interesting one, if it does not have enough energy to make BHs of its own). I therefore reject Hawking's argument that clocks stop as they approach the event horizon of a black hole. As I thought was well known, they only appear to do so to an observer watching them from outside the BH's event horizon, relying on photons from the clock. If you were travelling with the clock, time would not seem to stop, and the clock would get to cross the event horizon. If it did not, a black hole could not grow, and everything it "feeds" on would be forever orbiting it, never falling in. Thus, the "stopping" is observer frame-dependent Unfortunately, Hawking appears, in one of his TV programs, to tie his atheism to this clock-stopping idea.

So, great find LF, thank you.

Sorry I didn't post the link myself, but I got fed up years ago with doing just that!

More on the stopping of clocks at event horizons.
Obviously, it is the same phenomenon as the red-shifting of photons that come near the event horizon to be pulled into it - an outside observer only sees it approach, and get more and more red-shifted. (EDIT: I'm sure Hawking realized that, but science reporters might not have.) The phenomenon is related to the effect of climbing up a strong gravitational potential gradient, as occurs near an event horizon.
Also, the "logical inconsistencies" in Hawking were not so much about clock-stopping (it's only apparent to the remote observer, the clock keeps going as far as it is concerned), but also about his big bang coming from nothing, because that is a violation of the principle of conservation of total energy, one of the principles I attempt to maintain in my multiverse.