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Explanation: How far away is spiral galaxy NGC 4921? Although presently estimated to be about 320 million light years distant, a more precise determination could be coupled with its known recession speed to help humanity better calibrate the expansion rate of the entire visible universe. Toward this goal, this image was taken by the Hubble Space Telescope in order to help identify key stellar distance markers know as Cepheid variable stars. Since NGC 4921 is a member of the Coma Cluster of Galaxies, refining its distance would also allow a better distance determination to one of the largest nearby clusters in the local universe. The magnificent spiral NGC 4921 has been informally dubbed anemic because of its low rate of star formation and low surface brightness. The remarkably sharp image was made with Hubble's Advanced Camera for Surveys, currently in need of repair. Visible in the image are, from the center, a bright nucleus, a bright central bar, a prominent ring of dark dust, blue clusters of recently formed stars, several smaller companion galaxies, unrelated galaxies in the far distant universe, and unrelated stars in our Milky Way Galaxy.
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: spiral galaxy
Publications with words: spiral galaxy
See also:
- APOD: 2025 August 28 Á Galaxies, Stars, and Dust
- APOD: 2025 August 22 Á A Tale of Two Nebulae
- APOD: 2025 August 19 Á Giant Galaxies in Pavo
- APOD: 2025 August 18 Á NGC 1309: A Useful Spiral Galaxy
- APOD: 2025 July 4 Á NGC 6946 and NGC 6939
- APOD: 2025 June 30 Á NGC 4651: The Umbrella Galaxy
- APOD: 2025 June 19 Á NGC 3521: Galaxy in a Bubble