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.
Our knowledge of space changes all the time as new discoveries are made. But some ideas about the universe have never really held water – including the one that everything is made of frozen H2O.
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?