In diameter, spirals range from about 10,000 to over 300,000 light-years, and in mass from about one billion to 500 billion solar masses. Spiral structure can apparently exist only in disk galaxies above a certain size and, although spirals represent 80% of the bright galaxies in regions outside of rich clusters, there are no spirals with masses as low as those of many irregular galaxies and dwarf ellipticals.
Our own Milky Way Galaxy, together with the nearby Andromeda Galaxy, are both large spiral galaxies. Other relatively close and well known spirals include the Triangulum Galaxy, the Whirlpool Galaxy, the Sunflower Galaxy, the Black Eye Galaxy, the Sombrero Galaxy, M74, M81, and M101.
Related entry galaxy classification
Related category GALAXIES
Home • About • Copyright © The Worlds of David Darling • Encyclopedia of Alternative Energy • Contact