What stars are part of the Big Dipper?

The Big Dipper is one of the biggest asterisms in the Northern Hemisphere, and it is made up of eight stars.

The Big Dipper, also known as the Plough, is a massive asterism in the constellation Ursa Major. It is one of the most familiar star shapes in the Northern Hemisphere. In the past, the Big Dipper was often used as a navigation tool.

© NASA/Donald R. Pettit

An asterism on the other hand is a pattern, or group of stars that can be seen in the night sky. They range from simple shapes of just a few stars, to collections of multiple stars covering large areas of the sky. The stars can be bright naked-eye objects, or fainter, but they are all usually all of a similar brightness.

The brighter, larger asterisms are very useful for people who are familiarizing themselves with the night sky. The Big Dipper is made up of eight stars. Seven stars are visible at a glance. However, the eighth star is only observable with the naked eye in an area with a clear sky.

The stars making up the Big Dipper are Phecda, Alioth, Merak, Megrez, Dubhe, Mizar and Alkaid. In the same line of sight as Mizar, but one light-year beyond it, is the star Alcor. Together they are known as the Horse and the Rider.

Alcor would normally be quite easy to see with the naked eye, but its proximity to Mizar renders it more difficult to resolve. Five of the stars are at the core of the Ursa Major Moving Group. While the two at the ends, Alkaid and Dubhe, are not part of the group. Instead, they are moving in the opposite direction.

It is believed that these two stars are moving down and to the right of the map. Over time, this will change the Dipper’s shape, with the bowl opening up and the handle becoming more bent. Scientists revealed that in 50 000 years, the Dipper will no longer exist as we know it. Instead, it will be re-formed into a new Dipper facing the opposite way.