a galaxy having the visible form of a spiral
also spiral nebula
spiral galaxy
spiral galaxyWebster's New World College Dictionary, Fifth Edition Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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spiral galaxy
noun
A galaxy consisting of a rotating flattened disk with a central bulge made up mostly of old stars, from which extend two or more spiral arms made up mostly of younger stars and large amounts of interstellar gas and dust.
spiral galaxy
Messier 81
THE AMERICAN HERITAGE® DICTIONARY OF THE ENGLISH LANGUAGE, FIFTH EDITION by the Editors of the American Heritage Dictionaries. Copyright © 2016, 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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"Spiral galaxy." YourDictionary. LoveToKnow. www.yourdictionary.com/spiral-galaxy.
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Spiral galaxy. (n.d.). In YourDictionary. Retrieved from https://www.yourdictionary.com/spiral-galaxy
A galaxy consisting of a rotating flattened disk with an ellipsoidal central bulge from which extend a pattern of two or more luminous spiral arms. Spiral galaxies range from large bulges with tightly wound arms (classified as Sa) to small bulges with loosely wound arms (classified as Sc and in some cases Sd). The majority of the mass of a spiral galaxy is contained in its bulge, made up mostly of old stars, while the arms are composed mostly of younger stars and large amounts of interstellar gas and dust. A spherical, relatively dust-free region known as a galactic halo surrounding a spiral galaxy may contain large amounts of dark matter. The Milky Way is a spiral galaxy.
See illustration at galaxy Compare elliptical galaxy See more at Hubble classification system
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"Spiral galaxy." YourDictionary. LoveToKnow. www.yourdictionary.com/spiral-galaxy.
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Spiral galaxy. (n.d.). In YourDictionary. Retrieved from https://www.yourdictionary.com/spiral-galaxy
English Wiktionary. Available under CC-BY-SA license.
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"Spiral galaxy." YourDictionary. LoveToKnow. www.yourdictionary.com/spiral-galaxy.
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Spiral galaxy. (n.d.). In YourDictionary. Retrieved from https://www.yourdictionary.com/spiral-galaxy
