Explanation:
NGC
4631 is a big beautiful spiral galaxy.
Seen edge-on, it lies
only 25 million light-years away in the well-trained northern
constellation
Canes
Venatici.
The galaxy's slightly distorted wedge shape suggests to
some a cosmic herring and to others its popular moniker,
The Whale Galaxy.
Either way,
it is similar in size to our own Milky Way.
In this
gorgeous color image, the galaxy's yellowish core, dark dust clouds,
bright blue star clusters, and red star forming regions are easy
to spot.
A companion
galaxy, the small elliptical NGC 4627, is just above the
Whale Galaxy.
Out of view, off the lower edge
of the picture lies another distorted galaxy, hockey stick-shaped
NGC 4656.
The distortions and mingling
trails
of gas and dust detected at other
wavelengths suggest that all three galaxies have had close encounters
with each other in their past.
The Whale Galaxy is also known to have spouted
a halo of hot gas glowing
in x-rays.
digg_url = 'http://apod.nasa.gov/apod/ap090502.html'; digg_skin = 'compact';
