What is the Big Dipper?
The Big Dipper is a pattern of seven bright stars shaped like a ladle or saucepan. It is part of the constellation Ursa Major, the Great Bear, and is visible all year from much of the Northern Hemisphere.
The Big Dipper's four stars form a bowl, and three stars form a curved handle. Because it is not an official constellation, astronomers call it an asterism. In the United Kingdom and Ireland, it is often called the Plough, and in other places it is known as the Saucepan or the Great Wagon.
The two stars on the outer edge of the bowl, Dubhe and Merak, point toward Polaris, the North Star. Following the curve of the handle leads to the bright orange star Arcturus, a trick remembered by the phrase arc to Arcturus.
A changing shape
Five of the Big Dipper's stars move together through space as part of a group called the Ursa Major Moving Group. Over tens of thousands of years, the stars' movements will slowly change the Dipper's shape. In about 100,000 years, it will look quite different.
Did You Know?
Mizar, the middle star in the handle, has a faint companion called Alcor. Being able to see both was once used as a test of good eyesight.