What makes polaris the north star special

This trend continues until the traveler reaches the geographic not magnetic North Pole. At this point 90 degrees latitude , Polaris is 90 degrees above the northern horizon and appears directly overhead. Elmore further asked, "Did travelers in the past actually depend on the North Star to guide them? Thus, Polaris is a handy tool for finding the northern extent of one's position, or latitude, and was therefore heavily utilized by travelers in the pastespecially sailors.

Unfortunately, latitude alone is insufficient to pinpoint a location on the surface of the earth. Lines of constant latitude circle the earth parallel to the equator. With only latitude in hand, an individual knows just that he or she is on a particular "latitude circle.

Although many cultures succeeded in making long ocean voyages using only the stars, weather and currents, the "longitude problem" plagued sailors for millennia and remained unsolved until the invention of a clock that could keep accurate time while a ship rolled, pitched and yawed on the sea circa Furthermore, Polaris is not an absolute guide to measuring latitude on the earth for Northern Hemisphere observers. In addition to the daily hour rotation cycle, the axis of the earth precesses in a conical motion.

Thus, the projection of the earth's axis traces a circle in the northern and southern sky with a period of 26, years. The location of the North and South Celestial Pole is defined by projecting the axis of the earth onto the celestial sphere; consequently, as the axis changes position, so, too, does the "North Star.

Similarly, in 12, years the star Vega in the constellation Lyra will be the North Star. While the first show ended up being a bust, a relatively strong meteor shower was reported in Polaris is located in the constellation of Ursa Minor, the Little Bear. It sometimes also goes by the name " Stella Polaris.

Polaris, the North Star, lies at the end of the handle of the Little Dipper, whose stars are rather faint. Its four faintest stars can be blotted out with very little moonlight or street lighting. The best way to find your way to Polaris is to use the so-called "Pointer" stars in the bowl of the Big Dipper , Dubhe and Merak.

Just draw a line between these two stars and extend it out about 5 times, and you eventually will arrive in the vicinity of Polaris. Interestingly, the Big and Little Dippers are arranged so that when one is upright, the other is upside down. In addition, their handles appear to extend in opposite directions. Of course, the Big Dipper is by far the brighter of the two, appearing as a long-handled pan, while the Little Dipper resembles a dim ladle.

Polaris is located at a distance of light-years from Earth and has luminosity nearly 4, times that of our sun. Polaris shines at 2nd magnitude. On this astronomers' scale, smaller numbers represent brighter objects, with the brightest stars and planets in the night sky at around magnitude zero or even negative magnitudes.

The North Star it is a "pulsing" star, a Cepheid variable , which appears to vary in brightness ever so slightly — only one tenth of a magnitude — over a time frame of just under four days.

If you have a small telescope and train it on Polaris, you just might notice a tiny companion star called Polaris B shining at 9th magnitude with a pale bluish tint.

This companion was first sighted by Sir William Herschel in just a year later, Herschel would discover the planet Uranus. Astronomers believe that the two stars — A and B — are separated by about 2, astronomical units — one astronomical unit a. The orbital period of the two stars may number in the many thousands of years. In , by studying the spectrum of Polaris, a third companion star Polaris C was discovered. If that imaginary line — the axis — is projected into space above the north pole, it points to Earth's north celestial pole.

Polaris, located almost exactly at the north celestial pole, the center of spin, stays in the same place, while stars farther away from the north celestial pole can be seen to move in a wider circle around Polaris as viewed from Earth during its daily rotation. Polaris actually lies just a short distance away from where Earth's axis points. Polaris is located about 1 degree off to the side of the north celestial pole, so Polaris does move a little, tracing a very small arc in the night sky, around which the other visible stars make wider circles.

This picture of the night sky above Hawaii was taken by leaving the camera shutter open for a long time. The picture captures the apparent movement of the stars caused by Earth's rotation on its axis. Polaris is the star in the center of the star field; it shows essentially no movement.

Earth's axis points almost directly to Polaris, so this star is observed to show the least movement. The other stars appear to trace arcs of movement because of Earth's spin on its axis.