Dancing helps galaxies lose weight!Byline: ANI Washington, July 30 (ANI): In an interesting new research, astronomers have determined that dwarf spheroidal galaxies Dwarf spheroidal galaxy (dSph) is a term in astronomy applied to the nine low luminosity dwarf elliptical galaxies that are companions to the Milky Way and to the similar systems that are companions to the Andromeda Galaxy M31. , which contain few stars relative to their total mass, are formed by indulging in a cosmic dance. Dwarf spheroidal galaxies appear to be made mostly of dark matter - a mysterious substance detectable only by its gravitational grav·i·ta·tion n. 1. Physics a. The natural phenomenon of attraction between physical objects with mass or energy. b. The act or process of moving under the influence of this attraction. 2. influence, which outweighs normal matter by a factor of five to one in the universe as a whole. Astronomers have found it difficult to explain the origin of dwarf spheroidal galaxies. Previous theories require that dwarf spheroidals orbit near large galaxies like the Milky Way Milky Way, the galaxy of which the sun and solar system are a part, seen as a broad band of light arching across the night sky from horizon to horizon; if not blocked by the horizon, it would be seen as a circle around the entire sky. , but this does not explain how dwarfs that have been observed in the outskirts of the "Local Group" of galaxies could have formed. "These systems are 'elves' of the early universe, and understanding how they formed is a principal goal of modern cosmology," said lead author Elena D'Onghia of the Harvard-Smithsonian Center for Astrophysics The Harvard-Smithsonian Center for Astrophysics (CfA) is located in Cambridge, Massachusetts. It consists of the Harvard College Observatory and the Smithsonian Astrophysical Observatory. The Center is located at 60 Garden Street. (CfA). D'Onghia and her colleagues used computer simulations to examine two scenarios for the formation of dwarf spheroidals. While the first scenario features an encounter between two dwarf galaxies far from giants like the Milky Way, with the dwarf spheroidal spheroidal /sphe·roi·dal/ (sfer-oi´d'l) resembling a sphere. spheroidal resembling a sphere. later accreted into the Milky Way, the second scenario simulates an encounter between a dwarf galaxy and the forming Milky Way in the early universe. The team found that the galactic encounters excite a gravitational process which they term "resonant stripping," leading to the removal of stars from the smaller dwarf over the course of the interaction and transforming it into a dwarf spheroidal. "Like in a cosmic dance, the encounter triggers a gravitational resonance that strips stars and gas from the dwarf galaxy, producing long visible tails and bridges of stars," explained D'Onghia. "This mechanism explains the most important characteristic of dwarf spheroidals, which is that they are dark-matter dominated," added co-author Gurtina Besla. The long streams of stars pulled off by gravitational interactions should be detectable. For example, the recently discovered bridge of stars between Leo IV Leo IV, Byzantine emperor Leo IV (Leo the Khazar), d. 780, Byzantine emperor (775–80), son and successor of Constantine V. He owed his nickname to his mother, a Khazar princess. Leo tempered the iconoclastic excesses of his father's reign. and Leo V Leo V, Byzantine emperor Leo V (Leo the Armenian), d. 820, Byzantine emperor (813–20), successor of Michael I. A former general, Leo successfully defended (813) Constantinople against the Bulgars and concluded a 30-year truce with them. , two nearby dwarf spheroidal galaxies, may have resulted from resonant stripping. (ANI) Copyright 2009 Asian News International The Asian News International (ANI) agency provides multimedia news to China and 50 bureaus in India. It covers virtually all of South Asia since its foundation and presently claims, on its official website, to be the leading South Asia-wide news agency. (ANI) - All Rights Reserved. Provided by Syndigate.info an Albawaba.com company |
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