This week on Looking Up Hal reminds us that Polaris is not always the North Star.
Chances are, if there is anything you know about navigating around the night sky, it is that you can use the front two stars of the Big Dipper to find Polaris, the North Star. In the pre-GPS world, lots of navigation, from sailing ships to aircraft to even spacecraft, relied on celestial navigation to find their way home. And, for about the last 1500 years or so, Polaris has been the star everyone used. But did you know that this was not always the case?