In the constellation Hydra can be found a
spectacular face-on spiral galaxy. This is M83, the Southern
Pinwheel Galaxy. It earned its name from the distinct pinwheel
shape of its long spiral arms. Color photographs of this galaxy
reveal a wide range of colors from the yellow central core of
old stars to the blue spiral arms of young stars. Several red
knots can also be seen. These are gaseous nebulae where active
star formation is taking place. Dark lanes of dust are also
visible throughout the galaxy's disk. M83 is situated about 15
million light-years from Earth. It is receding from us at around
337 km/sec. This galaxy has been the site of six supernovae,
which is more than any other Messier galaxy. It was also the
first galaxy to be discovered beyond the local group.
