M51-The Whirlpool Galaxy
11 x 7 arc minutes
Canes Venatici (The Hunting Dogs)
M51 is a
large, spiral galaxy colliding with a smaller cousin. Thick dust lanes spiral
outward from M51's nucleus. One of these dust lanes partially blocks the light
from the upper third of the companion galaxy, attenuating the light and
coloring it reddish-brown. Careful inspection of the spiral arms in M51 reveals
small, bluish knots of light. Some of these features are believed to be
globular star clusters similar to our Milky Way's M13.
total mass is estimated to be about 160 billion suns, and its diameter is about
100,000 light years. Its total luminosity is about 10 billion suns.