The North Star, or Polaris, is a star that, by coincidence, happens to be located almost directly over the North Pole of the Earth. It has been used for centuries by people in the northern half of the Earth as a pointer toward north and as a measure of how far north one is from the equator (latitude). The European discoverers who sailed to the New World in the 15th and 16th centuries no doubt used this star to help them navigate. People who become lost today can use this star to help them determine which direction they should go in. However, there will come a time when we no longer have a North Star.The Earth spins around its axis, or center of rotation, one full turn every 24 hours. Think of it as a spinning top, or a gyrascope. A top or gyrascope not only spins rapidly, it also has a slow wobble-like motion in a circular pattern. So does the Earth. That is, the direction that the top of the Earth (the North Pole) points in, slowly goes around in a circular motion, like the wobble of a top. This is called precession.
It takes the Earth 26,000 years to wobble around once. As precession occurs, the alignment of what is over our North Pole changes (precession also explains the changing of "ages" - the so called "dawning of the age of Aquarius", which is actually about 600 years away). Our current North Star is about two moon diameters away from true north (the equivalent distance of twice the width of the moon as we see it), and is still getting closer. In the year 2095 it will be the nearest to true north, about one moon diameter away.
Then it will begin getting further from true north, until it can no longer be used as a North Star. For many milenia there will be no North Star. Thousands of years from now a brighter star, Vega, will come close enough to alignment with our North Pole to be used as our North Star.
In 26,000 years the earth's slow circular wobble will return it to its present position. The star we currently call the North Star will return to its alignment with the earth's North Pole. It will once again be our North Star.
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