January 6, 1999: Astronomers using the Hubble telescope have obtained the sharpest view yet of a glowing loop of gas called the Ring Nebula (M57), first cataloged more than 200 years ago by French astronomer Charles Messier.
The pictures reveal that the "Ring" is actually a cylinder of gas seen almost end-on. Such elongated shapes are common among other planetary nebulae, because thick disks of gas and dust form a waist around a dying star. This "waist" slows down the expansion of material ejected by the doomed object. The easiest escape route for this cast-off material is above and below the star. This photo reveals dark, elongated clumps of material embedded in the gas at the edge of the nebula; the dying central star is floating in a blue haze of hot gas.See the rest: