Robby
03-07-2008, 06:42 AM
http://antwrp.gsfc.nasa.gov/apod/image/0803/HolmesNGC1499_heden800.jpg (http://antwrp.gsfc.nasa.gov/apod/image/0803/HolmesNGC1499_heden.jpg)
Comet over California
Credit & Copyright (http://antwrp.gsfc.nasa.gov/apod/lib/ about_apod.html#srapply): P-M Hedén (http://www.clearskies.se/) (Clear Skies (http://www.clearskies.se/), TWAN (http://www.twanight.org/))
Explanation: Still gracing northern skies, a fading Comet Holmes lies at the top edge of this colorful skyview (http://www.clearskies.se/Comet%20Holmes%20&%20NGC1499.htm), recorded on March 4. The reddish emission nebula below it is NGC 1499, also known as the California Nebula (http://antwrp.gsfc.nasa.gov/apod/ap050310.html) for its resemblance to the outline of the state on the US west coast. Of course, the two cosmic clouds by chance lie along nearly the same line-of-sight and so only appear to be close together and of similar size. The California Nebula is actually about 100 light-years long and 1,500 light-years away, drifting through the Orion Arm of our spiral Milky Way Galaxy. Comet Holmes (http://antwrp.gsfc.nasa.gov/apod/ap080205.html) is about 20 light-seconds (http://www.haydenplanetarium.org/universe/duguide/ app_light_travel_time_dista.php) in diameter, sweeping through our solar system a mere 25 light-minutes (http://www.haydenplanetarium.org/universe/duguide/ app_light_travel_time_dista.php) away, beyond the orbit of Mars. The molecules of the comet's gaseous coma (http://www.windows.ucar.edu/tour/ link=/comets/coma.html&edu=high) fluoresce (http://www.ifa.hawaii.edu/faculty/jewitt/ spectral-excitation.html) in sunlight. The California Nebula's glow is characteristic of hydrogen atoms recombining with long lost (http://antwrp.gsfc.nasa.gov/apod/lib/lament.html) electrons, originally stripped away (ionized (http://csep10.phys.utk.edu/astr162/lect/light/ ionization.html)) by ultraviolet starlight. Providing the energetic starlight is Xi Persei (http://en.wikipedia.org/wiki/Perseus_constellation), the prominent star below the nebula.
(Via NASA (http://antwrp.gsfc.nasa.gov/apod/ap080307.html))
Comet over California
Credit & Copyright (http://antwrp.gsfc.nasa.gov/apod/lib/ about_apod.html#srapply): P-M Hedén (http://www.clearskies.se/) (Clear Skies (http://www.clearskies.se/), TWAN (http://www.twanight.org/))
Explanation: Still gracing northern skies, a fading Comet Holmes lies at the top edge of this colorful skyview (http://www.clearskies.se/Comet%20Holmes%20&%20NGC1499.htm), recorded on March 4. The reddish emission nebula below it is NGC 1499, also known as the California Nebula (http://antwrp.gsfc.nasa.gov/apod/ap050310.html) for its resemblance to the outline of the state on the US west coast. Of course, the two cosmic clouds by chance lie along nearly the same line-of-sight and so only appear to be close together and of similar size. The California Nebula is actually about 100 light-years long and 1,500 light-years away, drifting through the Orion Arm of our spiral Milky Way Galaxy. Comet Holmes (http://antwrp.gsfc.nasa.gov/apod/ap080205.html) is about 20 light-seconds (http://www.haydenplanetarium.org/universe/duguide/ app_light_travel_time_dista.php) in diameter, sweeping through our solar system a mere 25 light-minutes (http://www.haydenplanetarium.org/universe/duguide/ app_light_travel_time_dista.php) away, beyond the orbit of Mars. The molecules of the comet's gaseous coma (http://www.windows.ucar.edu/tour/ link=/comets/coma.html&edu=high) fluoresce (http://www.ifa.hawaii.edu/faculty/jewitt/ spectral-excitation.html) in sunlight. The California Nebula's glow is characteristic of hydrogen atoms recombining with long lost (http://antwrp.gsfc.nasa.gov/apod/lib/lament.html) electrons, originally stripped away (ionized (http://csep10.phys.utk.edu/astr162/lect/light/ ionization.html)) by ultraviolet starlight. Providing the energetic starlight is Xi Persei (http://en.wikipedia.org/wiki/Perseus_constellation), the prominent star below the nebula.
(Via NASA (http://antwrp.gsfc.nasa.gov/apod/ap080307.html))