But we can gain some idea of the magnitude of the stars when we consider the distance to arrive at, which is a most difficult task, for figures seem scarcely long enough to count the millions of miles, and no instrument can detect the parallax. Even supposing the parallax to be a very small fraction of a degree we should get a result equalling trillions of miles. No. 61 in Cygni was at one time continually observed by Professor Bessel, and he found that its distance—and it is the nearest star—is sixty-two and a half trillions of miles.
Fig. 611.—The Southern Cross.
Let us consider what this means. Light comes to us from the sun (91,000,000 of miles) in about eight minutes, and travels at the rate of something like 186,000 miles in a second. But even at that astounding rate the light from the star called 61 Cygni took ten years to reach the earth; and there are stars whose light has never yet reached the earth, although the gleam may have been travelling at 186,000 miles a second for thousands of years. And we may presume that though we still see the light of stars, some of them may be dead, but the light left is still progressing to us through space.
So we must conclude that some stars which look large, as do Vega and Sirius for instance, must be enormous “suns,” a great deal larger than our sun, and the stars are each the centre of invisible systems just as our sun is the centre of the “solar” system. Vega is a tremendous star, and shines with her own light as do all other visible stars; for reflected light, so very visible in the moon, which is close to us, would be quite invisible at such tremendous distances. So we must call these stars “suns,” and may add an apparently astonishing fact, that our own sun is merely one of the stars in the Galaxy, or “Milky Way”!
CHAPTER XLI.
THE STARS—(continued).
DOUBLE AND MULTIPLE STARS—COLOURED AND VARIABLE STARS—CLUSTERS, GROUPS, AND NEBULÆ—THE GALAXY, OR MILKY WAY—HOW TO FIND OUT THE PRINCIPAL STARS.