Page:The Music of the Spheres.djvu/220

 the bright faces of Sirius, Capella and other great stars to seem suddenly close.

This path of stars, called the Milky Way, stretches entirely around the sky, or seems to do so, because our solar system rests almost within its center—"almost" meaning within about 60,000 light years, which is comparatively close to the center of a Galaxy some 300,000 light years in diameter. If we could step off the earth and look at these stars they would appear as a gigantic wreath; as it is, we see one half of the wreath from the northern hemisphere and the other half by traveling to the southern hemisphere. At least this much of the ancient conception of the universe was correct—that our earth was situated near its center—but the idea that the sun, moon and stars whirled around it for its particular benefit, is looked upon as a vast conceit.

We now know for a certainty that our glorious Galaxy of stars is itself but an item in space, for since the recent investigations with the 60- and the 100-inch telescopes at Mount Wilson observatory with which the outer portions of the spiral nebulæ were resolved into swarms of stars, we know that there are hundreds of thousands of Galaxies separated from ours by a million light years, and from one another equally far. Probably the smaller nebulæ are even more remote. And we used to imagine that our own Galaxy floated through an infinite void of boundless space as lorn and lonely as Wordsworth's "cloud"! Then science goes still further and wonders if all these Galaxies form a part of a starry region which extends indefinitely in all directions or whether the star producing region is limited and surrounded by empty space!