NGC 6888, also known a the Crescent Nebula, isa cosmic bubble of interstellar gas about 25 light-years across.Created bywinds from the bright, massive star seen near the centerof this composite image, theshocked filaments of gas glowing at opticalwavelengths are represented in green and yellowish hues X-rayimage data from a portion of the nebula viewed bythe Chandra Observatory is overlaid in blue.Such isolate stellar windbubbles are not usually seen toproduc energetic x-rays, which requireheating gas to a million degrees celsius.Still, NGC 6888 seems to have accomplished thisas slow moving winds from the central star's initial transitionto a red supergiantwere overtaken and rammed by fasterwinds driven by the intense radiation from the star'sexposed inner layers Burning fuelat a prodigious rate and near the endof its stellar life, NGC 6888's central starshould ultimately go out with a bang, creating a supernovaexplosion in 100,000 years or so.NGC 6888 is about 5,000 light-years close, toward the constellatio Cygnus.
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