Gourt > Science > Physics > Particle > Astro Particle > Dark Matter
- This refers to the cosmological use of the term. For other uses, see Dark matter (disambiguation)
In cosmology, dark matter refers to matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation (light) to be detected directly, but whose presence may be inferred from gravitational effects on visible matter such as stars and galaxies. Dark matter explains several anomalous astronomical observations, such as anomalies in the rotational speed of galaxies (the galaxy rotation problem). Estimates of the amount of matter present in galaxies, based on gravitational effects, consistently suggest that there is far more matter than is directly observable. The existence of dark matter also resolves a number of seeming inconsistencies in the Big Bang theory, and is crucial for structure formation.
The dark matter component has vastly more mass than the "visible" component of the universe At present, the density of ordinary baryons and radiation in the universe is estimated to be equivalent to about one hydrogen atom per cubic meter of space. Only about 4% of the total energy density in the universe (as inferred from gravitational effects) can be seen directly. About 22% is thought to be composed of dark matter. The remaining 74% is thought to consist of dark energy, an even stranger component, distributed diffusely in space. baryonic dark matter) makes a contribution to dark matter, but constitutes only a small portion *" target="_blank" >[http://arxiv.org/abs/astro-ph/0002058. Determining the nature of this missing mass is one of the most important problems in modern cosmology and particle physics. Its urgency is underlined by David B. Cline in a 2003 article in Scientific American, in which he writes: "The terms . . . 'dark matter' and 'dark energy,' serve mainly as expressions of our ignorance", much as the marking of early maps with 'Terra Incognita'.
More on [ Dark matter ]
Cosmology :: Astronomy
Cosmology :: Physics
Completed Dark Matter Excavation #epicpetwars http://www.epicpetwars.com
mycatisakkk (roecky) Fri, 18 Dec 2009 04:23:53 -0000
Completed Dark Matter Excavation #epicpetwars http://www.epicpetwars.com
RT @TEDchris: Has dark matter finally been detected? http://bit.ly/6QS2lz
VeraFBirkenbihl (Vera F. Birkenbihl) Fri, 18 Dec 2009 04:22:44 -0000
RT @TEDchris: Has dark matter finally been detected? http://bit.ly/6QS2lz
RT @TEDchris: Has dark matter finally been detected? www.bit.ly/6QS2lz
globetrek (Globe Trek) Fri, 18 Dec 2009 04:21:23 -0000
RT @TEDchris: Has dark matter finally been detected? www.bit.ly/6QS2lz
RT @TEDchris: Has dark matter finally been detected? http://bit.ly/6QS2lz
canadianwild (canadianwild) Fri, 18 Dec 2009 04:19:28 -0000
RT @TEDchris: Has dark matter finally been detected? http://bit.ly/6QS2lz
Has Dark Matter finally been detected? http://bit.ly/4KdoSb
stelpavlou (Stel Pavlou) Fri, 18 Dec 2009 04:19:08 -0000
Has Dark Matter finally been detected? http://bit.ly/4KdoSb
RT @TEDchris: Has dark matter finally been detected? http://bit.ly/6QS2lz
_mattdavidson (Matt Davidson) Fri, 18 Dec 2009 04:18:41 -0000
RT @TEDchris: Has dark matter finally been detected? http://bit.ly/6QS2lz
CDMS - Cryogenic Dark Matter Search; searching for WIMPs with large germanium crystal cooled to 20 mK.
Chandra X-Ray Observatory: Dark Matter Mystery - A brief popular science type introduction to the subject.
CRESST - Cryogenic Rare Event Search with Superconducting Thermometers; a search for dark matter in the Gran Sasso laboratories.
DAMA - Experiment searching for dark matter with low activity scintillators in the Gran Sasso laboratories.
Dark Energy and the Microwave Background - Theory and measurements of sizes of fluctuations of cosmic microwave background agree with omega=1 giving a strong evidence for dark matter.
Meta Description: [ A portion of Number 479 ]
Dark Mass and the Quest for the Æther - A brief discussion on the semantics of mass, matter and weight.
Meta Description: [ The law of conservation of matter states that
matter cannot be created or destroyed. However, according to Einstein, the MASS
of that matter is linked to energy. Dark MATTER may not exist - it may just be
misunderstood MASS ]
Dark Matter (by Martin White) - Comprehensive description with links to detailed summaries, including plots, graphs and schematics.
Dark Matter Annihilation at the Galactic Center - Physics News Update.
Meta Description: [ A portion of Number 446 ]
Dark Matter as the Fundamental Particle of the Universe - An individual interpretation on the structure of the Universe.
Meta Description: [ Dark matter,The search for the origin of the universe has taken us deeper and deeper into the heart of the micro element world ]
404
Dark Matter, Cosmology, and Large-Scale Structure of the Universe - A detailed discussion of the various pieces of gravitational evidence for the existence of dark matter, the different forms it might take, and their impact on cosmological theories.
404
Dark Matter, Cosmology, and Large-Scale Structure of the Universe - A dark matter tutorial.
Discussion about Dark Matter - An informative radio transcript of two scientists talking about dark matter.
404
Is Dark Matter Theory or Fact? - From Scientific American: Ask the Experts: Physics.
Meta Description: [ Science questions and science expert answers in chemistry, physics, astronomy, mathematics, computers, environment, geology, medicine ]
LSST Observatory - Large-aperture Synoptic Survey Telescope ('Dark Matter Telescope'): proposed 8.4 m, 7 square-degree field telescope.
Mirror Matter - The concept of mirror matter is explained. Mirror matter could form a sizable fraction of the inferred dark matter.
Primer on Dark Matter - Very concise illustrated overview with links to relevant topics and sub-topics.
404
The Dark Side of the Universe - Workshop in Aspen, June 19 - July 9, 2000.
The Early History of Dark Matter - The history of the discovery of dark matter in the Universe is reviewed. Emphasis on early work by Zwicky (1933), Smith (1936), Babcock (1939) and Oort (1940).
The Picasso Project; A Dark Matter Search Experiment - The PICASSO project: A Dark Matter Search Experiment based on a Superheated Droplet Detector.
UK Dark Matter Collaboration - UK search for Galactic WIMP dark matter.
What is Dark Matter? - From the Usenet Physics FAQ.
White Dwarfs Shed Light on Dark Matter - Report (March 23/01) of astronomical evidence suggesting white dwarf stars are a potential source for dark matter. Findings also contribute to stellar evolution theory.
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