green, and red. Some are single, but others are held together in pairs
or groups by the force of gravitation. From their immense distance they
appear fixed to us, but in reality they are flying in all directions at
enormous velocities. Alpha, of the constellation Cygnus, for example, is
coming towards us at a speed of 500 million leagues per annum, and some
move a great deal faster. Most of them probably have planets circling
round them in different stages of growth, but these are invisible to us.
Here and there amongst them we find luminous patches or 'nebulæ,' which
prove to be either clusters of stars or stupendous clouds of glowing
gases. Our sun is a solitary blue star on the verge of the Milky Way, 20
billion miles from Alpha Centauri his next-door neighbour. He is
travelling in a straight line towards the constellation Hercules at the
rate of 20,000 miles an hour, much quicker than a rifle bullet; and,
nevertheless, he will take more than a million years to cover the
distance. Eight large or major planets, with their satellites, and a
flock of minor planets or planetoids, are revolving round him as their
common centre and luminary at various distances, but all in the same
direction. The orbits, or paths, about the sun are ovals or ellipses,
almost circular, of which the sun occupies one focus, and they are so
nearly in one plane, or at one level, that if seen from the sun, they
would appear to wander along a narrow belt of the heavens, called the
zodiac, which extends a few degrees on each side of the Elliptic or
apparent course of the sun against the stars. The planets are all
globes, more or less flat at the poles, like an orange, and each is
turning and swaying on its axis, thus exposing every part to the light
and warmth of the sun. They are divided by the planetoids into an inner
and an outer band. The inner four are Mercury, Venus, the Earth, and
Mars; the outer four are Jupiter, Saturn, Uranus, and Neptune. Moreover,
a number of comets and swarms of meteoric stones or meteorites are
circulating round the sun in eccentric paths, which cross those of the