Big Dipper

Big Dipper changes over time

How the Big Dipper's shape will change over the next 100,000 years.

The Big Dipper is the familiar bright seven-star asterism in the constellation Ursa Major, known in Britain as the Plough. The five middle stars are all moving through space together as part of a loosely-bound group known as the Ursa Major Moving Cluster. Alkaid (Eta, leftmost star in diagram) and Dubhe (Alpha), however, are moving in their own directions, ultimately dooming the Dipper's shape.