Star-Clouds, Star-Clusters, and Star-Streams

In the preceding chapter we have seen something of the strangely
complicated structure of the Galaxy, or Milky Way. We now proceed to
study more comprehensively that garlanded ``Pathway of the Gods.''

Judged by the eye alone, the Milky Way is one of the most delicately
beautiful phenomena in the entire realm of nature -- a shimmer of
silvery gauze stretched across the sky; but studied in the light of
its revelations, it is the most stupendous object presented to human
ken. Let us consider, first, its appearance to ordinary vision. Its
apparent position in the sky shifts according to the season. On a
serene, cloudless summer evening, in the absence of the moon, whose
light obscures it, one sees the Galaxy spanning the heavens from north
to southeast of the zenith like a phosphorescent arch. In early spring
it forms a similar but, upon the whole, less brilliant arch west of
the zenith. Between spring and summer it lies like a long, faint,
twilight band along the northern horizon. At the beginning of winter
it again forms an arch, this time spanning the sky from east to west,
a little north of the zenith. These are its positions as viewed from
the mean latitude of the United States. Even the beginner in
star-gazing does not have to watch it throughout the year in order to
be convinced that it is, in reality, a great circle, extending
entirely around the celestial sphere. We appear to be situated near
its center, but its periphery is evidently far away in the depths of
space.

Although to the casual observer it seems but a delicate scarf of
light, brighter in some places than in others, but hazy and indefinite