 Everyone knows that Polaris is the North Star, but did you know that this will actually change? In just 5,470 years, this star, Alderamin, will be the North Star, and in about 13,000 years, it will have changed again to the super-bright star Vega. So why does the North Star change over time? The main reason is that Earth is not quite spherical. It's actually slightly wider at the equator than it is at the poles. And this equatorial bulge interacts with the Sun and Moon's gravity to give the spinning Earth a little wobble that we call procession. The whole processional cycle for the Earth takes about 26,000 years, and in that time, many different stars will be the ones closest to the North Celestial Pole, and whichever one is closest at any given time is what we call the North Star. Polaris was closest to the North Celestial Pole in 2017, but now is getting further and further away from it every day.