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Dark matter

Beyond the Standard Model Standard Model Hierarchy problem Dark matter Cosmological constant problem Strong CP problem Neutrino oscillation Technicolor Kaluza–Klein theory Grand Unified Theory Theory of everything String theory Superfluid vacuum theory MSSM Superstring theory Supergravity String theory Loop quantum gravity Causal dynamical triangulation Causal fermion systems Causal sets Canonical quantum gravity Superfluid vacuum theory Gran Sasso INO LHC SNO Super-K Tevatron NO?A v t e Part of a series on Physical cosmology Big Bang Universe Age of the universe Chronology of the universe Inflation Nucleosynthesis Backgrounds Gravitational wave (GWB) Microwave (CMB) Neutrino (CNB) Expansion Future Hubble's law Redshift Metric expansion of space FLRW metric Friedmann equations Future of an expanding universe Ultimate fate of the universe Components Structure Lambda-CDM model Dark energy Dark matter Shape of the universe Galaxy filament Galaxy formation Large quasar group Large-scale structure Reionization Structure formation BOOMERanG Cosmic Background Explorer (COBE) Illustris project Planck space observatory Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey ("2dF") Wilkinson Microwave Anisotropy Probe (WMAP) Aaronson Alfvén Alpher Bharadwaj Copernicus de Sitter Dicke Ehlers Einstein Ellis Friedman Galileo Gamow Guth Hawking Hubble Lemaître Mather Newton Penrose Penzias Rubin Schmidt Smoot Suntzeff Sunyaev Tolman Wilson Zel'dovich List of cosmologists Discovery of cosmic microwave background radiation History of the Big Bang theory Religious interpretations of the Big Bang theory Timeline of cosmological theories  Category Astronomy portal v t e Estimated distribution of matter and energy in the universe, today (top) and when the CMB was released (bottom) Dark matter is a kind of matter hypothesized in astronomy and cosmology to account for gravitational effects that appear to be the result of invisible mass. Dark matter cannot be seen directly with telescopes; evidently it neither emits nor absorbs light or other electromagnetic radiation at any significant level. It is otherwise hypothesized to simply be matter that is not reactant to light. Instead, the existence and properties of dark matter are inferred from its gravitational effects on visible matter, radiation, and the large-scale structure of the universe. According to the Planck mission team, and based on the standard model of cosmology, the total mass–energy of the known universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy. Thus, dark matter is estimated to constitute 84.5% of the total matter in the universe, while dark energy plus dark matter constitute 95.1% of the total content of the universe.Astrophysicists hypothesized dark matter because of discrepancies between the mass of large astronomical objects determined from their gravitational effects and the mass calculated from the "luminous matter" they contain: stars, gas, and dust. Although based upon flawed or inadequate evidence, dark matter was postulated by Jan Oort in 1932 to account for the orbital velocities of stars in the Milky Way and by Fritz Zwicky in 1933 to account for evidence of "missing mass" in the orbital velocities of galaxies in clusters. Adequate evidence from galaxy rotation curves was discovered by Horace W. Babcock in 1939, but was not attributed to dark matter. The first to postulate dark matter based upon robust evidence was Vera Rubin in the 1960s–1970s, using galaxy rotation curves. Subsequently, many other observations have indicated the presence of dark matter in the universe, including gravitational lensing of background objects by galaxy clusters such as the Bullet Cluster, the temperature distribution of hot gas in galaxies and clusters of galaxies, and more recently the pattern of anisotropies in the cosmic microwave background. According to consensus among cosmologists, dark matter is composed primarily of a not yet characterized type of subatomic particle.The search for this particle, by a variety of means, is one of the major efforts in particle physics today.Although the existence of dark matter is generally accepted by the mainstream scientific community, some alternative theories of gravity have been proposed, such as MOND and TeVeS, which try to account for the anomalous observations without requiring additional matter. ^ Trimble, V. (1987). "Existence and nature of dark matter in the universe". Annual Review of Astronomy and Astrophysics 25: 425–472. Bibcode:1987ARA&A..25..425T. doi:10.1146/annurev.aa.25.090187.002233.  ^ Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; et al. (Planck Collaboration) (22 March 2013). "Planck 2013 results. I. Overview of products and scientific results – Table 9". Astronomy and Astrophysics 1303: 5062. arXiv:1303.5062. Bibcode:2013arXiv1303.5062P.  ^ Francis, Matthew (22 March 2013). "First Planck results: the Universe is still weird and interesting". Arstechnica.  ^ "Planck captures portrait of the young Universe, revealing earliest light". University of Cambridge. 21 March 2013. Retrieved 21 March 2013.  ^ Sean Carroll, Ph.D., Cal Tech, 2007, The Teaching Company, Dark Matter, Dark Energy: The Dark Side of the Universe, Guidebook Part 2 page 46, Accessed Oct. 7, 2013, "...dark matter: An invisible, essentially collisionless component of matter that makes up about 25 percent of the energy density of the universe... it's a different kind of particle... something not yet observed in the laboratory..." ^ First observational evidence of dark matter. Darkmatterphysics.com. Retrieved on 6 August 2013. ^ Cite error: The named reference Rubin1970 was invoked but never defined (see the help page). ^ Copi, C. J.; Schramm, D. N.; Turner, M. S. (1995). "Big-Bang Nucleosynthesis and the Baryon Density of the Universe". Science 267 (5195): 192–199. arXiv:astro-ph/9407006. Bibcode:1995Sci...267..192C. doi:10.1126/science.7809624. PMID 7809624.  ^ Bergstrom, L. (2000). "Non-baryonic dark matter: Observational evidence and detection methods". Reports on Progress in Physics 63 (5): 793–841. arXiv:hep-ph/0002126. Bibcode:2000RPPh...63..793B. doi:10.1088/0034-4885/63/5/2r3.  ^ Bertone, G.; Hooper, D.; Silk, J. (2005). "Particle dark matter: Evidence, candidates and constraints". Physics Reports 405 (5–6): 279–390. arXiv:hep-ph/0404175. Bibcode:2005PhR...405..279B. doi:10.1016/j.physrep.2004.08.031.
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