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Closed Universe
Closed UniverseWithin standard Big Bang cosmology essentially only three futures are available for the physical universe. The universe is either open, which means it will continue to expand at an ever increasing rate; or it is flat, which means it will only expand at a rate just sufficient to avoid collapse; or it is closed, which means the universe will expand to a maximum size and then collapse in upon itself. The total mass-density of the universe determines which scenario will be realized. At a critical mass-density, the universe is flat. If the mass-density is higher than the critical level, the universe is closed. Certain astronomical measurements suggest that the universe is very nearly flat, and yet estimates of mass-density are far below the critical level. This has led scientists to suspect that there is a great deal of matter as yet undetected. Whether there is enough of this unseen dark matter to cause the recollapse of the universe is a still unresolved question. See also Big Bang Theory; Big Crunch Theory; Cosmology, Physical Aspects mark worthing |
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WORTHING, MARK. "Closed Universe." Encyclopedia of Science and Religion. 2003. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. WORTHING, MARK. "Closed Universe." Encyclopedia of Science and Religion. 2003. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1G2-3404200096.html WORTHING, MARK. "Closed Universe." Encyclopedia of Science and Religion. 2003. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3404200096.html |
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closed universe
closed universe A universe which is finite in size, has a finite lifetime, and in which space is positively curved. A Friedmann universe with density greater than the critical density is an example. See also curvature of spacetime.
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"closed universe." A Dictionary of Astronomy. 1997. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. "closed universe." A Dictionary of Astronomy. 1997. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O80-closeduniverse.html "closed universe." A Dictionary of Astronomy. 1997. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-closeduniverse.html |
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