Information AboutUniverse |
| CATEGORIES ABOUT UNIVERSE | |
| universe | |
| environmentsuniverse | |
| environments | |
| physical cosmology | |
| nature | |
| astronomical dynamical systems | |
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The Universe is defined as the summation of all particles and energy that exist and the Space-time in which all events occur. Based on observations of the portion of the Universe that is Observable , physicists attempt to describe the whole of space-time, including all Matter and Energy and events which occur, as a single system corresponding to a Mathematical Model . The generally accepted Scientific Theory which describes the origin and evolution of the Universe is Big Bang Cosmology , which describes the Expansion Of Space from an extremely hot and dense state of unknown characteristics. The Universe underwent a rapid period of Cosmic Inflation that flattened out nearly all initial irregularities in the energy density; thereafter the universe expanded and became steadily cooler and less dense. Minor variations in the distribution of mass resulted in hierarchical segregation of the features that are found in the current universe; such as Clusters and Supercluster s of Galaxies . There are more than one hundred billion (1011) galaxies in the Universe,1 each containing hundreds of billions of stars, with each star containing about 1057 Atoms of hydrogen. ETYMOLOGY The word "universe" is derived from the Old French ''univers'', from Latin ''universa'', which combines ''uni''- (the combining form of ''unus'', or "one") with ''versus'' (perfect passive participle of ''vertere'', or "turn"). The word, therefore, means "all turned into one" or "revolving as one". NAME OF OUR UNIVERSE In the same way that '' The Moon '' refers to our ( Earth 's) moon, ''the Universe'' is used by some cosmologists to refer to our Universe. In this article, ''the Universe'' is equivalent to ''our observable Universe''. Theoretical and Observational Cosmologists vary in their usage of the term ''the Universe'' to mean either this whole system or just a part of this system. JSTOR: One Universe or Many? As used by observational cosmologists, ''the Universe'' most frequently refers to the finite part of space-time. The Universe is directly observable by making Observation s using Telescope s and other detectors, and by using the methods of theoretical and empirical Physics for studying its components. Physical cosmologists assume that the observable part of ( Comoving ) space (also called ''our universe'') corresponds to a part of a model of the whole of space, and usually not to the whole space. They use the term ''the Universe'' ambiguously to mean either the observable part of space, the observable part of space-time, or the entire space-time. In order to clarify terminology, George Ellis , U. Kirchner and W.R. Stoeger recommend using the term ''the Universe'' for the theoretical model of all of the connected space-time in which we live, ''universe domain'' for the observable universe or a similar part of the same space-time, ''universe'' for a general space-time (either our own ''Universe'' or another one disconnected from our own), ''multiverse'' for a Set of disconnected space-times, and ''multi-domain universe'' to refer to a model of the whole of a single connected space-time in the sense of Chaotic Inflation models. OBSERVABLE PORTION See Also: Observable universe |
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