MP3 + PDF | Professor James B. Kaler, University of Illinois at Urbana-Champaign
Even to the unaided eye, the sky displays a richness of sights. Stars of dif- ferent brightnesses and colors spangle the blackness of night. Here and there are pairs and clusters. If the right time of year, a band of white encircles the heavens, the Milky Way, bejewelled with bright stars and stamped with mys- terious voids. Binoculars and small telescopes reveal more: the Milky Way is made of countless faint stars, while double stars, clusters, and clouds of swirling gas abound. Powerful telescopes that span the spectrum of radiation, both on the ground and flying above the Earthâs atmosphere, have broken open much of the mystery of the starry sky, while at the same time enhancing its beauty. We know the Milky Way is the manifestation of our disk-shaped Galaxy of some 200 billion stars, and that its dark clouds are the starsâ hidden birthplaces. From there we can trace the flow of their lives to their deaths as burnt cinders or in powerful explosions that leave behind some of the most bizarre charac- ters to be found anywhere.