CTB 102 
Stars are not eternal. They're born, they live, and they die.
Their birthplaces are vast clouds of gas and dust. The best-known of these stellar nurseries is the Orion Nebula. It's home to thousands of newborn stars, and it's so bright that it's visible to the unaided eye on winter evenings.
Astronomers recently found a much farther stellar nursery that's one of the largest in the entire Milky Way galaxy -- more than 10 times bigger than the Orion Nebula.
CTB 102 is 14,000 light-years from Earth. It's in the constellation Cygnus, the swan, which floats gracefully through the glow of the Milky Way on summer nights. Look for the swan well up in the east at nightfall, with its body parallel to the horizon and its wings extending above and below.
Like the Orion Nebula, CTB 102 probably has thousands of newborn stars. But thick clouds of dust between the nebula and Earth block the visible light from its many stars. Fortunately, though, radio waves penetrate the dust. Astronomers have used radio waves to map the nebula's total extent.
They estimate that CTB 102 is about 380 light-years across. It may owe that enormous size to the very stars it's created. The hottest and most massive of these stars blow strong winds that push the gas and dust outward -- making this unseen stellar nursery one of the biggest in the galaxy.
Tomorrow: flying saucers around a distant planet.
Script by Ken Croswell, Copyright 2010