Tue Apr 19, 2016 STAR COMPARISONS

In our Milky Way galaxy alone there are an estimated 200 billion stars. They vary in mass and size. Some, like the red supergiant star Betelgeuse, which can be found in the constellation Orion over in the western sky this evening, are as large as the span of the inner solar system. Others, like the blue giant Rigel, also in Orion, are many times hotter and more massive than the sun. Then there are white dwarf stars like the companion star to Sirius in the southwest - only the size of the earth. Smaller still are neutron stars, just a few miles in diameter. And what about black holes, mere pinpoints of super-dense matter. From red and blue giants to yellow suns, white dwarfs, neutron stars and black holes, from solitary suns to multiple star systems, and great globular clusters, each star is unique, possessing within it the secret of its own creation and demise.