Friday, March 7, 2008

3.9 APOD Comet over California


Guess what? Comet Holmes is still freaking in the sky! Who knew. It's fading, but apparently visible in the northern skies. On March 4th, it was in the same area as the red emission nebula the California Nebula. The cool thing I found about this picture is that the two objects appear to be about the sameish size, but Comet Holmes is only 25 light minutes away and 20 light seconds in diameter, whereas the California Nebula is about 100 light years long and 1500 light years away. The bright star is Xi Persei. The color of the California Nebula comes from hydrogen atoms recombining with "long lost" electrons that were originally ionized by UV star light.

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