Sky Children

A giant Hubble mosaic of the Crab
 Nebula, a supernova remnant.

       Did you ever try to count the sky's children; those nebulae, stars and planets which make the great, blue spaces above us so brilliant on a clear, cold, wintry night?

       The astronomers, the people who study the heavens and all the things there, tell us that we may see five thousand without the aid of a telescope, and that this number is but a handful compared to the vast numbers shown by photographs of the entire sky taken through a large telescope in an observatory.

       Some are so small and so far away that they appear as mere wisps of vapor floating in the air; some are much nearer and hang like lanterns against a blue ceiling, while others like our own Sun, are near enough for us to feel the heat produced as the light given off by the gases passes through the restless air about our own planet.

       What fun to watch a fire! First the coal or wood gives off gases, then bursts into flame. As we look we see that the flame changes from white to red, and then dies down completely. A somewhat similar change takes place among the stars.

       Whirling, swinging masses of gas which are moving through space form a Nebula. If we were able to follow its movements for a long, long time we might see some of the greenish-white curls twist about each other and other curls join those. For in some such way a baby star is formed. It has a thicker mass than the rest of the nebula and gradually pulls other loose particles to itself. Then its light becomes bright and we say, ''See how that star sparkles!" The twinkle is due to the fact that the vibration of the atmosphere breaks up the light and makes it oscillate or sparkle.

       When a star is at its hottest stage it is bluish-white. Then its intensity begins to lessen and it glows with a steady, golden-yellow color. Our own Sun is at this stage now. The swirling of its carbon, hydrogen, calcium, magnesium and iron gases causes great tongues of flame to extend out from the star. From these come the warm rays of light and heat which make it possible for us to live on the Earth. Do you know that it takes that light about eight minutes to travel from the Sun to the Earth?

       If you see a star with the colors of orange-red or red, that star is beginning to get old. Little by little the light will become fainter until the star is dark, or a planet. Just as our Earth and her six sister-planets revolve about the Sun, so those dark masses continue to turn about some other strong central star rushing on out there in space, unlighted except as they reflect the light of other stars.

       The power of pulling in stray bits of material, in time, results in a mass large enough to attract and hold gases such as carbon-dioxide, nitrogen and water-vapor.

       This is a very important step in the building of a land on which plants and people are to live. The gases form an atmosphere, that all-enclosing envelope of air that surrounds the Earth. The water-vapor changes into rain, which tumbles down the sides of the great volcanic masses cutting deep valleys and filling in the hollows. Soon the crust is covered with soil, the warm rays of a sun shine upon the surface and the planet becomes a beautiful land.

       We think our Sun an immense body. So it is when compared with objects about us, but to an observer on some other planet revolving about some other sun, our Sun would appear as a tiny point of light only, for there are thousands of stars larger and more brilliant.

       Look out a window that faces to the south on some clear, cold night. The most noticeable feature will be the constellation known as Orion. Of all star groups, this is the largest, the most interesting, and the most beautiful. It may be seen by boys and girls in every part of the Earth.

       Orion, according to the Grecian legend, was a famous hunter whose death was caused by the sting of a scorpion. After death both giant and scorpion were placed in the sky. To find this mighty giant, look, first, for three bright stars in a straight line, each star equally distant from the other. This is Orion's Belt. To the right is Betelgeuse on the giant's shoulder. It is a famous orange-red star. The bright blue star in the left ankle is called Rigel and is the brightest star in the group. Hanging from the right side of the Belt is his sword. This contains the Great Nebula, which is bat-shaped and the most marvelous thing of its kind in our sky.

       To the left of the slanting Belt is Sirius in the mouth of Canis Major, the hunter's favorite dog. Sirius is bright blue. Who has not noticed this great, twinkling mass of light? It is so near, so friendly, and so brilliant, and gives thirty times, as much light as our Sun.

       Other noted groups to be observed in the winter sky are Leo, the lion, crouching in the east; the Great Bear or Big Dipper treading in a circle around the North Star, and the Heavenly Twins in the Milky Way. All are children of the sky. Cornell.

The Milky Way as viewed from La Silla Observatory