THE NUMBER OF STARS
Reading edition
When the heavens are viewed with the naked eye, a few hundred stars may perhaps be seen—some bright, some faint. Viewed through opera glasses, many more stars may been seen; while their number is again greatly increased by the use of a telescope. The larger and more powerful the telescope employed, the greater the number of stars thus discovered in the depths of space. The interesting question thus arises: What is the total number of stars in the entire firmament? Can they be estimated? And if so, what would their approximate number be?
What we call “stars” are, of course, in practically all cases suns—often vastly larger and hotter than our own. These stars differ from one another in order of brilliance; some are brighter than others. They are accordingly classified according to their order of brilliance, and known as stars of the “First Magnitude,” of the “Second Magnitude,” etc., up to about the Seventeenth Magnitude. Any star of a given magnitude is, roughly, about two-and-a-half times as brilliant as one of the next lower order, and this variation holds throughout—each magnitude being that much greater in brilliance.
The “magnitude” of the stars varies according to their light-giving power, and also their distance from us. One of the methods adapted to measure the magnitude is to compare its brightness with an artificial star, gradually cutting-off its light by means of neutral, tinted glass until the two are equal. The color of the star must be taken into account, in such measurements, the eye being more sensitive to some colors than to others.
Now, it is an interesting and significant fact that the number of the stars decreases as their magnitude decreases; that is to say, the greatest number of stars are found of the first magnitude; a lesser number of the second; still less of the third, and so on (broadly speaking). After reaching the ninth magnitude, the number very rapidly diminishes. It has been calculated that there are about 120,000,000 stars in the first 16 or 17 magnitudes. If the proportion were maintained throughout, however, there would be more than ten times that number. Some authorities have asserted that there are, roughly, half a billion stars of varying magnitudes in the heavens.