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The Fabric of the Cosmos

by HawkLogic
Tags: cosmos, fabric
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HawkLogic
#1
Jul19-12, 01:30 PM
P: 12
My cosmology friend and I were watching an episode of NOVA called "The Fabric of the Cosmos" hosted by Brian Greene.

I asked if he could further explain the reference to the "fabric of the cosmos".
He said,
"Space-time has a geometry much like a piece of fabric.
Picture our universe being constantly woven, sewn, mended, and extended on a great cosmic loom.
The loom is driven by a treadle, which in turn is driven by a treadle beneath it."
I asked, "What drives that lower treadle?"

He said the funniest thing.
How do you think he replied?
Spoiler
He said, "Isn't it obvious? It's treadles all the way down."
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Naty1
#2
Jul19-12, 01:49 PM
P: 5,632
Oh my gosh!!
Referring to 'spacetime FABRIC' has heretofore been a good way unleash the wrath of some purists who don't think of space that way....who don't see spacetime as a physical entity. I know I have been pilloried here some years ago despite reasonable evidence to the contrary. I still bear 'psychological scars' [LOL]

In any case, things evolve as evidenced by the following which might well set off another group who hold the metric in unique and singular regard, and also is likely to offend cosmologists who view their realm as predominant:

It is therefore natural to think of the current accelerated expansion
of the universe as an evolution towards holographic equipartition. Treating the expansion of the universe as conceptually equivalent to the emergence of space we conclude that the emergence of space itself is being driven towards holographic equipartition.

in the overall cosmological evolution matter dominated phase is not of much significance since it again quickly gives way to the second de Sitter phase dominated by the cosmological constant. Viewed in this manner, the domain of conventional cosmology merely describes the emergence of matter degrees of freedom along with cosmic space during the time the universe is making a transition from one de Sitter phase to another.
In a way, the problem of the cosmos has now been reduced to understanding one
single number N closely related to the number of modes which cross the Hubble radius during the three phases of the evolution..
Emergent perspective of Gravity and Dark Energy
http://arxiv.org/abs/1207.0505
http://www.physicsforums.com/showthread.php?t=618397

Authors:T. Padmanabhan
(Submitted on 2 Jul 2012)
Colmarino
#3
Jan16-13, 04:33 AM
P: 2
I'm currently finishing reading Fabric of Cosmos but since this edition is back from 2004, I would really which to find which next book I should get to be sort of at pare with nowadays discussions.

marcus
#4
Jan16-13, 11:40 AM
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The Fabric of the Cosmos

Here are the cosmology best-sellers, you might look at some of the online reviews:
http://www.amazon.com/Best-Sellers-B...s/books/13449/

I've seen very favorable comment about two that are at the top of the list:

Neil Shubin
The Universe Within: Discovering the Common History of Rocks, Planets, and People

Jim Holt
Why Does the World Exist?: An Existential Detective Story
Naty1
#5
Jan17-13, 08:43 AM
P: 5,632
I'm currently finishing reading Fabric of Cosmos but since this edition is back from 2004....,
So is mine and I have not found any discrepancies regarding current discussions here.

Depending on what avenue you'd like to read, consider Leonard Susskind's THE BLACK HOLE WAR, "My battle with Stephen Hawking to make the world safe for quantum mechanics." My copy is 2008. He offers a great series of foundational discussions, no math.

THREE ROADS TO QUANTUM GRAVITY by Lee Smolin is also very interesting as he contrasts
Planck scale physics with general relativity. [2001]

The first book is more narrowly focused, the latter more general and shorter, but I found both excellent.
KenBakerMN
#6
Feb11-13, 08:29 AM
P: 11
I will hazard a guess: "It's treadles all the way down"?

Edit: D'oh! I wrote that before I mouse-overed the spoiler. Of course, that's a pun on Hawking's 'turtles' anecdote. Okay, I'm slowly catching up.


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