Which star is the North Star?
Have you looked up at the stars lately? I so enjoy stars... endless possibilities. I'm a dreamer. I know a few constellations, a few stars... though I wish I had paid more attention in Ujay's astronomy class in college. Living in the northern hemisphere, most people can find the big dipper, but the little dipper is probably the more important know to know because it is home to the North Star, known as Polaris.
The reason Polaris is so important is because the axis of Earth is pointed almost directly at it... *currently*... but I'll get back to that point. During the course of the night, Polaris does not rise or set, but remains in very nearly the same spot above the northern horizon year-round while the other stars circle around it (I have a time-lapse of the stars using Polaris as my center point and it turned out pretty cool).
Polaris is located in the constellation of Ursa Minor, (the Little Bear, or the Little Dipper). It sometimes also goes by the name "Stella Polaris." There are seven stars making up the constellation. Polaris, the North Star, lies at the end of the handle of the Little Dipper, whose stars are rather faint, making it more difficult to see. Its four faintest stars can be blotted out with very little moonlight or street lighting. The best way to find Polaris is to use the "Pointer" stars (Dubhe and Merak) making up the front of the bowl of the Big Dipper. Draw a line between these two stars and extend it out about 5 times their distance from each other, and you eventually will arrive near Polaris.
According to space.com, "exactly where you see Polaris in your northern sky depends on your latitude. From New York it's 41 degrees above the northern horizon, which also corresponds to the latitude of New York. Since 10 degrees is roughly equal to your clenched fist held at arm's length, from New York Polaris would appear to stand about "four fists" above the northern horizon. At the North Pole, you would find it overhead. At the equator, Polaris would appear to sit right on the horizon. So if you travel to the north, the North Star climbs progressively higher the farther north you go. When you head south, the star drops lower and ultimately disappears once you cross the equator and head into the Southern Hemisphere."
It should also be noted: Polaris is more accurate than a compass. A compass shows you the direction of the strongest magnetic force for a particular spot and for your particular time. But even Polaris isn't positioned exactly due north but standing about 0.7 degree which separates Polaris from directly north – the North Celestial Pole.
Let's get back to that *current* part. When measured over centuries, Polaris has not always been our North Star. The earth's axis wobbles a bit, so the north celestial pole shifts as the centuries go by. Polaris is actually still moving closer to the north celestial pole until March 24, 2100, when it will be as close to it as it ever will come. As for this "wobble", it takes about 25,800 years for the Earth's axis to complete a single wobble, different stars have become the North Star at different times. For example, the star Thuban in the constellation of Draco, the Dragon, was the North Star around the year 2600 B.C., during the age of the Pyramid builders of ancient Egypt. The brightest Guardian, Kochab, was the North Star at the time of Plato, around 400 B.C.
And around the year A.D. 14,000, Earth's axis will point close to the star Vega -- one of the brightest stars in the sky -- surely making the move easy for the title "North Star".
All that being said, I'm still a fan of Betelgeuse, the red star in the constellation, Orion's Belt. Do you have a favorite star?