Dark Energy

In Physical cosmology, Astronomy and Celestial mechanics, dark Energy is a hypothetical form of Energy that permeates all of space and tends to increase the rate of expansion of the Universe. Dark energy is the most popular way to explain recent observations and experiments that the Universe appears to be expanding at an accelerating rate. In the Standard model of cosmology, dark Energy currently accounts for 74 of the total mass-energy of the universe.

Two proposed forms for dark energy are the Cosmological constant, a constant Energy density filling space homogeneously, and scalar fields such as quintessence or moduli, dynamic quantities whose energy Density can vary in time and space. Contributions from scalar fields that are constant in space are usually also included in the Cosmological constant. The Cosmological constant is physically equivalent to Vacuum Energy. Scalar fields which do change in space can be difficult to distinguish from a cosmological constant because the change may be extremely slow.

High-precision measurements of the expansion of the universe are required to understand how the expansion rate changes over time. In General relativity, the evolution of the expansion rate is parameterized by the cosmological equation of state . Measuring the equation of state of dark energy is one of the biggest efforts in Observational cosmology today.

1. Dark Energy - Introduction - This site is intended for students age 14 and up, and for anyone interested in learning about our universe.
2. HubbleSite - Hubble Discoveries - Dark Energy - Search all of HubbleSite
3. physicsworld.com - physicsworld.com - news, views and information for the global physics community from Institute of Physics Publishing
4. Dark Energy, Dark Matter - NASA Science - What is dark energy? More is unknown than is known we know how much there is, and we know some of its properties other than that, dark energy is a mystery but an

1. 2010-09-06T14:15:46Z : What is Dark Energy? - Associated Content - In April 1990, when the Hubble Space Telescope HST was launched into orbit, scientist had high hopes that the telescope would help them map out the visible universe however, few were really prepared for ... (Associated Content)
2. 2010-09-09T03:20:49Z : Homeowner struggles in quest for energy savings - Orlando Sentinel - Two months after University Acres resident Charlie Piper launched a fight with her homeowners association for an energy-efficient white roof, her house remains covered by the same old, dark-gray shingles ... (Orlando Sentinel)
3. 2010-09-07T10:11:12Z : Cinnafilm Descends on IBC with Dark Energy 2.0 and Plug-ins for Rhozet - The four months between NAB and IBC are usually reserved for putting the finishing touches on products announced at NAB and readied for sale at IBC. Certainly, this was no different for Cinnafilm in spite of its ... (PR Inside)
4. 2010-09-01T16:59:11Z : Void that is truly empty solves dark energy puzzle - New Scientist - EMPTY space may really be empty. Though quantum theory suggests that a vacuum should be fizzing with particle activity, it turns out that this paradoxical picture of nothingness may not be needed. A calmer view of ... (New Scientist)

1. 2010-09-09T05:02:53Z : Adam Drummond, TheAdamDrummond - Yeah its midnight and I'm still full of energy after laying in my dark room for an hour. Now I'm bored so I'm going running.
2. 2010-09-09T04:54:09Z : enrique servin, Kike_Gavilan - RT @CraftLass RT @b0yle "More than 70% of the universe is made of nothing" RT @AstroPHYPapers: Frontiers of Dark Energy bit.ly/a5X3Fc
3. 2010-09-09T04:23:15Z : Astrophysics Papers, AstroPHYPapers - Unification of Dark Matter and Dark Energy in a Modified Entropic Force Model. arxiv.org/abs/1009.1506
4. 2010-09-09T03:39:02Z : ☊ディージェイ❥ファンキー★フレッシュ™, DJ_PHUNKYPHRESH - RT @technon_yousuke: シュリケーン！！【mix】Shur-i-kan presents Dark Energy Radio Show March 2010　 soundcloud.com/shurikan/ dark - energy -radio-show-march-2010