Page:The Music of the Spheres.djvu/22

 the north pole of the earth, and is located in the sky by the "pointers" on the bowl of the Big Dipper. Since we cannot realize the whirling of the earth on its axis which causes the heavenly bodies to appear to pass in the opposite direction, it is the same to us as if the axis of the earth continued upward to Polaris, thus causing this star to seem to stand still, while all the other stars in the course of twenty-four hours seem to whirl in fixed orbits around it.

This remarkable performance may be photographed on a clear, moonless night if a camera is properly focused on the North Star and left exposed in that position for two or three hours. The photograph thus obtained will consist of a series of circular trails around the central star. These are produced by the stars moving slowly over the plate in consequence of their changing positions,—just as if the stars instead of our own little world had really moved. This is what the ancient peoples believed and in the words of Aratus

Since the stars were always in the same order with reference to one another, it was thought that perhaps these luminaries were the heads of golden nails which made the heavenly dome secure. Thus through their apparent immovability, they acquired the name of "fixed" stars, although this fixity has long since been disproved.

The stars nearest to the North Star complete their circles above the horizon and are called circumpolar stars. The Big Dipper, the Little Dipper, Draco and the "W" of Cassiopeia are star