· Get a Cloudy Nights T-Shirt · Submit a Review / Article Click here if you are having trouble logging into the forums Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User You are not logged in. [Login] Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar Speciality Forums >> Science! Astronomy & Space Exploration, and Others Previous   Index   Next   Threaded   Pages: 1 shawnhar Carpal Tunnel Reged: 06/25/10 Loc: Knoxville, TN Dark Energy Expansion in the Past - Question       #5601852 - 01/02/13 07:57 PM Edit   Reply   Quote Quick Reply   So my understanding is Dark Energy is causing the Universe to expand more rapidly as we move forward in time. My undertanding of the big bang is that it expanded faster than light in the beginning and then slowed down. My dumb logic says there must have been less dark energy in the past or the further you go back the slower things get, is that wrong? Was there some "hump" which once passed, would allow the expansion to speed up? Or has it always been expanding more rapidly than before? Is it possible dark energy is "leaking" into our space or being created now? Also, have there been any studies to determine if there is a correlation between the variations in the CMB and Dark Energy? Edited by shawnhar (01/02/13 08:14 PM) Post Extras:       Dave Mitsky Postmaster Reged: 04/08/02 Loc: PA, USA, Planet Earth Re: Dark Energy Expansion in the Past - Question [Re: shawnhar]       #5603073 - 01/03/13 02:00 PM Edit   Reply   Quote Quick Reply   According to what I've read, the effect of gravity on cosmological expansion became progressively weaker and that of dark energy grew progressively stronger as the universe evolved. The time at which dark energy began to dominate varies from 5 to 7 billion years ago, depending upon the source. At that point, the slowing of expansion due to gravity was overcome by the repulsive effect of dark energy. http://hetdex.org/dark_energy/dark_matter.php http://fire.biol.wwu.edu/trent/alles/Cosmic_Evolution.pdf (page 27) http://imgsrc.hubblesite.org/hu/db/images/hs-2001-09-g-full_jpg.jpg http://www.sciencenews.org/view/access/id/43609/description/COSMIC_TUG-OF-WAR Regarding your final question, browse http://kipac.stanford.edu/collab/research/highlights/tidbits2010/actsz Dave Mitsky Post Extras:       Carl Coker member Reged: 07/30/12 Loc: Ohio Re: Dark Energy Expansion in the Past - Question [Re: Dave Mitsky]       #5603148 - 01/03/13 02:41 PM Edit   Reply   Quote Quick Reply   Dave has it right. Since the total amount of matter and radiation has remained the same since the Big Bang, they necessarily dilute as the universe gets larger. Dark energy, so far as we can tell, does not do so; or, if it does (i.e., it is not actually a cosmological constant), it does so much more slowly than matter and radiation. Because of this, it eventually comes to dominate over the gravitational influence of matter and radiation. Post Extras:       Kon Dealer professor emeritus Reged: 01/05/11 Loc: Cambridge UK Re: Dark Energy Expansion in the Past - Question [Re: Carl Coker]       #5603447 - 01/03/13 06:05 PM Edit   Reply   Quote Quick Reply   So we are going out in a big "rip", rather than a big "crunch" Post Extras:       shawnhar Carpal Tunnel Reged: 06/25/10 Loc: Knoxville, TN Re: Dark Energy Expansion in the Past - Question [Re: Kon Dealer]       #5603501 - 01/03/13 06:42 PM Edit   Reply   Quote Quick Reply   Thanks for the awesome reading Dave! So there was a hump, cool. One of those articles seems to indicate there was no dark energy right after inflation, but there was lots of dark matter, that seems rather weird. I wonder if the clumping/collapse of hydrogen and other elements somehow spawned the dark energy. I love the fact that we don't know much about it. Post Extras:       sirchz super member Reged: 09/21/09 Re: Dark Energy Expansion in the Past - Question [Re: shawnhar]       #5604631 - 01/04/13 11:50 AM Edit   Reply   Quote Quick Reply   Here is a nice talk about dark energy. http://www-personal.umich.edu/~huterer/EPO/adler.pdf Post Extras:       Pages: 1 Previous   Index   Next   Threaded   Extra information 0 registered and 14 anonymous users are browsing this forum. 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