Explanation:
What's California doing in space?
Drifting through the Orion Arm of the spiral Milky Way Galaxy,
this
cosmic cloud
by chance echoes the outline of
California
on the west coast of the
United States.
Our own Sun also lies within the Milky Way's
Orion
Arm, only about 1,500 light-years from the
California Nebula.
Also known as NGC 1499, the classic emission nebula is around 100
light-years long.
On many images, the most prominent glow of the California Nebula is
the red light characteristic of
hydrogen
atoms recombining with long
lost electrons, stripped away (ionized)
by energetic starlight.
In the
above image, however, hydrogen is colored green, while sulfur is
mapped to red and
oxygen mapped to blue.
The star most likely providing the energetic
starlight that ionizes much of the nebular gas is the bright, hot, bluish
Xi Persei,
just outside the right image edge.
A regular target for astrophotographers,
the California Nebula
can be spotted
with a wide-field telescope under a dark sky
toward the constellation of
Perseus, not far from the
Pleiades.
Videos:
APOD site review (unbiased);
Previous week's APODs set to music (can you do better?)
