Comments on: Ep. 137: Large Scale Structure of the Universe http://www.astronomycast.com/astronomy/cosmology/ep-137-large-scale-structure-of-the-universe/ Take a weekly facts-based journey through the cosmos with Astronomy Cast. Thu, 11 Mar 2010 05:19:48 +0000 http://wordpress.org/?v=2.9.1 hourly 1 By: Helder Velez http://www.astronomycast.com/astronomy/cosmology/ep-137-large-scale-structure-of-the-universe/comment-page-1/#comment-2353 Helder Velez Tue, 30 Jun 2009 13:03:38 +0000 http://www.astronomycast.com/?p=743#comment-2353 As Steve in NC says and no one challenge: gravity radiation spreads at c speed. All codes simulating the evolution of the universe took the Newtonian approximation of infinite c speed. I've never saw a simulation or analysis of the most simple universe: homogeneous, infinite, euclidean, not expanding, no DM, no DE. As not seen in science articles I allow myself to say that the analysis can be seen here: http://outrafisica.blogs.sapo.pt (in Portuguese lang) If you digg you will find an explanation of the 'voids' (and also of the 'observed universe') At "The biggest void in space is 1 billion lightyears across" - link in this post at http://www.newscientist.com/article/dn12546 , you can confirm that void scale "..challenges theories of large-scale structure formation in the universe." ) As Steve in NC says and no one challenge: gravity radiation spreads at c speed. None is talking of the 'matter' -> 'gravity radiation' conversion that MUST happen at all times, following GR matter/energy equivalence, except here: http://arxiv.org/abs/astro-ph/0208365 and at http://outrafisica.blogs.sapo.pt (in Portuguese lang) As Steve in NC says and no one challenge: gravity radiation spreads at c speed. I remember that GR was put forward when it was consensual that the matter has an infinite age and gravity was already 'set' in the universe. Only later was acknowledged the finite age of the matter and of the gravity, but never translated into the GR formulation. As Steve in NC says and no one challenge: gravity radiation spreads at c speed.
All codes simulating the evolution of the universe took the Newtonian approximation of infinite c speed.
I've never saw a simulation or analysis of the most simple universe:
homogeneous, infinite, euclidean, not expanding, no DM, no DE.
As not seen in science articles I allow myself to say that the analysis can be seen here: http://outrafisica.blogs.sapo.pt (in Portuguese lang)
If you digg you will find an explanation of the 'voids' (and also of the 'observed universe')
At "The biggest void in space is 1 billion lightyears across" – link in this post at http://www.newscientist.com/article/dn12546 , you can confirm that void scale "..challenges theories of large-scale structure formation in the universe." )

As Steve in NC says and no one challenge: gravity radiation spreads at c speed.
None is talking of the 'matter' -> 'gravity radiation' conversion that MUST
happen at all times, following GR matter/energy equivalence, except here:

http://arxiv.org/abs/astro-ph/0208365

and at http://outrafisica.blogs.sapo.pt (in Portuguese lang)

As Steve in NC says and no one challenge: gravity radiation spreads at c speed.
I remember that GR was put forward when it was consensual that the matter has an infinite age and gravity was already 'set' in the universe. Only later was acknowledged the finite age of the matter and of the gravity, but never translated into the GR formulation.

]]> By: FoxJudsf http://www.astronomycast.com/astronomy/cosmology/ep-137-large-scale-structure-of-the-universe/comment-page-1/#comment-2260 FoxJudsf Fri, 05 Jun 2009 23:25:11 +0000 http://www.astronomycast.com/?p=743#comment-2260 Good, interesting article, but where took information? Good, interesting article, but where took information?

]]> By: Steve in NC http://www.astronomycast.com/astronomy/cosmology/ep-137-large-scale-structure-of-the-universe/comment-page-1/#comment-2238 Steve in NC Thu, 04 Jun 2009 13:42:08 +0000 http://www.astronomycast.com/?p=743#comment-2238 Given that gravity radiates at light speed (still thought to be true I believe) how do large scale structures maintain structure? It could take a goodly percentage of their age just to propagate gravitational field changes across the structure. I've never heard a really coherent discussion about how the universe maintains structure with gravity only moving at light speed. Given that gravity radiates at light speed (still thought to be true I believe) how do large scale structures maintain structure? It could take a goodly percentage of their age just to propagate gravitational field changes across the structure. I've never heard a really coherent discussion about how the universe maintains structure with gravity only moving at light speed.

]]> By: Rich http://www.astronomycast.com/astronomy/cosmology/ep-137-large-scale-structure-of-the-universe/comment-page-1/#comment-2189 Rich Tue, 02 Jun 2009 15:44:58 +0000 http://www.astronomycast.com/?p=743#comment-2189 For additional info check out Carolyn Collins Petersen's last month Episode of The Astronomer's Universe where she talks about "The Big Picture" and the large scale structure of the Universe! http://www.universetoday.com/2009/05/01/a-stunning-look-at-the-big-picture/ For additional info check out Carolyn Collins Petersen's last month Episode of The Astronomer's Universe where she talks about "The Big Picture" and the large scale structure of the Universe! http://www.universetoday.com/2009/05/01/a-stunning-look-at-the-big-picture/

]]> By: alex http://www.astronomycast.com/astronomy/cosmology/ep-137-large-scale-structure-of-the-universe/comment-page-1/#comment-2122 alex Fri, 29 May 2009 07:59:26 +0000 http://www.astronomycast.com/?p=743#comment-2122 If the redshifting in light indicates that all objects are expanding away from us indicating the big bang and the existence of dark matter then how do galaxies and super clusters collide and subsume each other. I know gravity and three body interactions are happening but where is the expansion . This process hints at ultimately everything that can merge will and over eons the voids will get bigger. hope that makes sense cheers alex from glasgow If the redshifting in light indicates that all objects are expanding away from us indicating the big bang and the existence of dark matter then how do galaxies and super clusters collide and subsume each other. I know gravity and three body interactions are happening but where is the expansion . This process hints at ultimately everything that can merge will and over eons the voids will get bigger.

hope that makes sense

cheers

alex from glasgow

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