Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

May 25, 1998
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M83: A Barred Spiral Galaxy
Credit: W. Keel (U. Alabama in Tuscaloosa), KPNO, 4-m Mayall Telescope

Explanation: M83 is a bright spiral galaxy that can be found with a small telescope in the constellation of Hydra. M83 is a member of the Centaurus group of galaxies, a nearby group dominated by the massive galaxy Centaurus A. It takes light about 15 million years to reach us from M83. The spiral arms are given a blue color by the many bright young stars that have recently formed there. Dark dust lanes are also visible. Stars and gas in spiral arms seem to be responding to much more mass than is visible here, implying that galaxies are predominantly composed of some sort of dark matter. Finding the nature of this dark matter remains one of the great challenges of modern science.

Tomorrow's picture: A Seemingly Square Sun

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
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&: Michigan Tech. U.