Whirlpool Galaxy (M51)
A detailed view of the Whirlpool galaxy's spiral arms and dust clouds, which are the birth sites of massive and luminous stars.
At only 30 million light years distant and 60 000 light years across, also called M51 or NGC 5194, is one of the brightest and most picturesque galaxies in the sky. Anyone with a good pair of binoculars can see this Whirlpool near the constellation of Canes Venatici.
Astronomers speculate that M51's spiral structure is primarily due to its gravitational interaction with a smaller, nearby companion galaxy, NGC 5195, just off the top of this image.
The companion's gravitational influence is triggering star formation in the Whirlpool, as seen by the numerous clusters of bright young stars, highlighted in red.
Last update: 9 March 2004