On a typical night, looking into the sky, you can see somewhere between 500 and 6000 stars, depending on how dark your night sky is. If you live in a reasonably dark area, you may be lucky enough to see a faint, diffuse band stretching across the sky, from horizon to horizon. This band, known as the Milky Way, is the plane of our home galaxy.
It was Galileo who discovered that this band consisted of an almost uncountable number of stars, after he turned his telescope to the sky. Prior to this, it was believed that the Milky Way was a ‘cloud’ that spanned the entire sky.
360-degree photographic panorama of the Milky Way. (Digital Sky LLC)
The Pale Blue Dot is a photograph of planet Earth taken in 1990 by Voyager 1 from a record distance, showing it against the vastness of space. Both the idea for taking the distant photo and the title came from scientist and astronomer Carl Sagan, who also wrote the 1994 book of the same name. In 2001, it was selected by Space.com as one of the top ten space science photos.
