Why does Polaris point north?
Polaris sits close to the north celestial pole, the point in the sky toward which Earth’s northern rotation axis points. As Earth turns, most stars appear to trace arcs across the sky; Polaris appears to move very little. Face it and you are looking roughly north.
Its height above the northern horizon is approximately your latitude in the Northern Hemisphere. The North Star is not generally visible from the Southern Hemisphere, so it is not a universal navigation aid.
Finding the North Star
Find the Big Dipper, part of Ursa Major. Imagine a line from the two stars at the outer edge of its bowl and extend it roughly five times their separation. The moderately bright star you encounter is Polaris, near the end of the Little Dipper’s handle. Trees, buildings, latitude and season can affect what you see.
A variable star with a changing role
Polaris changes brightness slightly and belongs to a class known as Cepheid variables. It is also part of a multiple-star system. The direction of Earth’s axis changes slowly over thousands of years, an effect called precession. Different stars can therefore serve as pole stars in different eras.
More than a landmark
Polaris is a useful starting point for learning the sky: once you know north, you can watch how stars appear to rotate around it. A phone compass or a star chart can help you check your first observations.