Jim Sheridan, age i3, of Omaha, Neb., for his question:
Which galaxy is nearest to our Milky Way?
Our Milky Way is a vast pin wheeling system of stars called a galaxy. Beyond the Milky Way are billions of other galaxies, some smaller and some perhaps larger than our own. Some of them Seem t0 be y0iiriger and leas well developed than our Big Pinwheel. The nearest galaxy similar to our own is called the Great Nebula in Andromeda.
There are a number of star clusters just outside the central core of our Milky Way. There are also two small star systems at a distance of about 100, 000 light years. They are the hazy Magellan Clouds, which can be seen in the sky from the Southern Hemisphere. The Clouds, however, are irregular star systems and so close to our Milky Way that it is hard to think of them as separate galaxies.
The closest galaxy, which can compare with our Milky Way, is in another part of the sky. It can be spotted without a telescope in Andromeda, a constellation of fall and early winter. What We See as a dim, oval shaped blurs is the Great Spiral Nebula in Andromeda, a pin wheeling system of stars very like our Milky Way? Astronomers, in fact, have learned a great deal about our Milky Way by studying this sister galaxy of ours.
The big telescopes have given us dazzling pictures of our sister galaxy. It is a flat disk of whirling stars with trailing arms spiraling out from its star crowded center. We do not see it as a circle because we have an edge on view of the spinning saucer. The vast nebula has been photographed in sections and the parts assembled to present a portrait of one of the most dazzling beauties in the heavens.
The star crowded nucleus is radiant with golden light. It is a close up of the hazy blur we see without a telescope, and we are told its golden radiance comes from old and cooler stars. The swirling arms are tinted with hazy blue. Here the stars are thinner and shrouded in trailing clouds of gas and cosmic dust. These stars are younger and they are whopping furnaces blazing with blue white heat.
Our sister galaxy may be somewhat larger than our Milky Way, and it is estimated to lie at a distance of perhaps i.5 million light years. In one light year, there are about 6 million ordinary miles.
Astronomers must study our Milky Way from a remote planet in the vast system, far from its center. Our position is inside the flat wheel, and our vita w is directly across its star crowded center. Astronomers have a better view of the Great Nebula in Andromeda, and this has shown them what to look for in our own galaxy. With the help of this blueprint, they have been able to trace the shape of our Milky Way.