spiral galaxy
a galaxy having a spiral structure.
Origin of spiral galaxy
1Words Nearby spiral galaxy
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024
How to use spiral galaxy in a sentence
This is because radio telescopes have always struggled to see the much fainter radio emission from normal spiral galaxies like our own Milky Way.
‘Dancing Ghosts’: A New, Deeper Scan of the Sky Throws Up Surprises for Astronomers | Ray Norris | August 5, 2021 | Singularity HubEMU sees almost all the spiral galaxies in the nearby universe that were previously seen only by optical and infrared telescopes.
‘Dancing Ghosts’: A New, Deeper Scan of the Sky Throws Up Surprises for Astronomers | Ray Norris | August 5, 2021 | Singularity HubAnother new Hubble image shows a large spiral galaxy that lies 490 million lightyears away.
With its latest fix, Hubble proves to be the telescope that just won’t quit | Monroe Hammond | July 20, 2021 | Popular-ScienceMany spiral galaxies, including the Milky Way, contain a central bar-shaped region densely packed with stars and surrounded by the galaxy’s pinwheeling arms.
Dark matter may slow the rotation of the Milky Way’s central bar of stars | Emily Conover | June 25, 2021 | Science NewsDifferent parts of spiral galaxies tend to host different types of stars.
Some fast radio bursts come from the spiral arms of other galaxies | Lisa Grossman | June 1, 2021 | Science News
Case in point: the spiral galaxy NGC 5548, which astronomers have been monitoring off and on for decades.
British Dictionary definitions for spiral galaxy
a galaxy consisting of an ellipsoidal nucleus of old stars from opposite sides of which arms, containing younger stars, spiral outwards around the nucleus. In a barred spiral the arms originate at the ends of a bar-shaped nucleus
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for spiral galaxy
[ spī′rəl ]
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.♦ A spiral galaxy whose central bulge has the shape of a bar from whose ends the spiral arms emanate is called a barred spiral galaxy. About a third of spiral galaxies have this straight or lozenge-shaped bar of stars, gas, and dust extending out from the nucleus. Barred spiral galaxies are classified similarly to regular spirals, from SBa (large bulge, tightly wound arms) to SBc (smaller bulge, looser arms). Astronomers believe that some elliptical galaxies containing hints of a bar and spiral might once have been barred spiral galaxies. See illustration at galaxy. Compare elliptical galaxy irregular galaxy lenticular galaxy. See more at Hubble classification system.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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