Ursa Major, or Great Bear, the constellation in the northern skies that contains the Big Dipper, a name suggested by the shape of the figure formed by its seven brightest stars. In mid-northern latitudes Ursa Major remains above the horizon day and night the year round. It can therefore be seen on any clear night.
When a huge star collapses, it releases massive amounts of radiation in concentrated streams. If one of those streams hit Earth, it wouldn't be pretty. But where should we put "gamma-ray bursts" on our list of anxieties?
A look at the night sky at any time of year will reveal a faint band of light stretching across the sky -- our solar system's home, the Milky Way. How much do we really know about it?