M51: The Whirlpool
Galaxy in Dust and Stars
The Whirlpool Galaxy is
a classic spiral galaxy. At only 30 million light years distant
and fully 60 thousand light years across, M51, also known as NGC 5194, is
one of the brightest and most picturesque
galaxies on the sky.
The below image is a digital
combination of a ground-based image from the 0.9-meter telescope at Kitt Peak National Observatory and a
space-based image from the Hubble
Space Telescope highlighting sharp features normally too
red to be seen.
Anyone with a good pair
of binoculars,
however, can see this Whirlpool toward
the constellation of
the Hunting Dogs (Canes
Venatici. M51 is
a spiral galaxy of type Sc and
is the dominant member of a whole group of galaxies.
Astronomers speculate
that M51's spiral structure is
primarily due to its gravitational
interaction with a smaller galaxy just off the top of the image.
Image Credit: N. Scoville (Caltech), T. Rector (U. Alaska, NOAO) et al., Hubble
Heritage Team, NASA
