BY CAMILLE FLAMMARION
Camille Flammarion (1842-1925): A popular French writer and lecturer onastronomy and other subjects.
This selection is from "The Wonders of the Heavens."The stars appear to be scattered at random in the heavens. On a fine starry night, when our sight rises to these heights, a great difference in their brightness is noticed, and at the same time a seeming disorder in their general arrangement. This irregular arrangement and the number of stars prevent us from giving each of them a particular name, but to recognize them and facilitate study, the heavenly sphere is divided into sections.
The astronomical knowledge or science of the ancients was very limited. They were at first contented to name the planets and a few of the most beautiful stars, and we have preserved some of the old names. They grouped together certain stars, each group being imagined to form the outlines of some animal or of some mythical1 hero, whose name was given to the group. Unless the imagination is vivid enough to create images of the figures represented, just as it sees pictures in the ever-1 Mythical: fabulous.
changing shapes of the clouds, one need not try to find in the constellations1 anything like the forms or outlines of the objects whose names they bear. The stars in each constellation are distinguished by Greek letters.
The necessity of being guided on the seas obliged man to choose in the heavens fixed points by which he could direct his course; and that need was probably the historical origin of the names of the constellations. More than three thousand years ago the constellations which we call Orion2, the Pleiades3, and the Hyades4, were mentioned by Job. Homer5, also, speaks of these constellations.
The ancients drew maps of the heavens, and from the time of Hipparchus6, a Greek astronomer who flourished about one hundred years before the Christian era, they were able to classify the stars, distinguishing them according to their brightness. It was necessary to have some method of finding a particular star easily, in the midst of the five or six thousand stars which may be seen with the naked eye on a clear night.
As the stars vary in brightness, in order to aid us in recognizing them they have been classed in order of magnitude7.
1Constellations: groups of fixed stars.
2Orion: a large, bright star, named for the fabulous hunter, Orion.
3Pleiades: a group of seven small stars, named for the seven daughters of the fabulous hero, Atlas.
4Hyades: a group of five stars, supposed by the ancients to foretell rainy weather when they rose with the sun.
5Homer: a Greek poet supposed to have lived about 1000 B.C. 6 Hipparchus: a Greek astronomer who lived about 150 B.C.
7 Magnitude: size.
The word "magnitude" is really a misnomer, as it has no relations to the dimensions of the stars; for we have been able to measure but few of these celestial bodies.
Formerly it was believed that the brightest stars were the largest, and this belief led people to rank the more brilliant stars as the larger ones. Thus, stars of the first magnitude are those which shine with the greatest brilliancy. Those of the second magnitude are less bright, and so on.