Kathy Walsh, age 13, Wichita, Kansas, for her question:
How far away is M 1?
If there were a beauty contest in the heavens as seen from our earth, x‑231 would certainly be namad Miss Universe. This great beauty is a spiral nebula, a vast cartwheel of stars like the galaxy in which we live. It has often neon called our sister galaxy. If our eyes could sloe it in all its glory, we would all be out on every starry night gazing in wonder.
Sad to say, all our unaided. eyes can see of Miss Universe is a faint glow, and that only on the clearest of nights. Like most great beauties, however, our sister galaxy does not mind being photographed. In telescope pictures she shows up in all her finery.
The time to look for Miss Universe is a clear, clear night in the f a11. For the great beauty appears in the: fall constellation Andromeda. This constellation is just east of the Great Square of Pegasus. Its stars form a rough dart, around which the ancients imagined a picture of the maiden Andromeda in chains. One star is ?t her head, two at her waist, two at her hips and two at her knees. In the old pictures, her chained hand extends slightly south of the stars at her hips. The chained wrist is a pale glow which is all our eyes can see of M1, Miss Universe or, as she is often called, the Great Nebula in Andromeda.
When you see that faint glow, your eyes are looking across 805, 000 light years. Each light year is equal. to about 6 million million. miles that is 12 followed by 12 zeros. You are looking across our own star‑filled galaxy which is 100,000 light years from side to side. From the rim of our galaxy you look on outward across the vast reaches of empty space. Far away as it is, M31 is the nearest galaxy to our own.
Studies of M1 have helped us get a picture of our own galaxy. Both are made of stars, billions and billions of stars. Both are shaped in huge spirals, thickest at the center and thinning out towards the edges. We are looking towards the dense center of our galaxy when we see the star‑packed Milky Way.
Our view of Miss Universe is from the edge of the great spiral. The dense center is aglow with light which piles off towards the edges. In telescope pictures, the Great Nebula in Andromeda looks rather like a huge daisy bowing its head in the rain. is not quite as large as our galaxy. From side to side it measures 60,000 light years as compared with our galaxy's 100,000. The distance between the two sister galaxies, then, is more than eight times the width of our giant galaxy. Of course, 805,000 light years is a distance greater than our minds can grasp, 2t means that traveling at the speed of light, which is about 186,000 miles a second, we could reach Miss Universe in 805,000 years, The pale glow we see of the Great Nebula set out on its way towards us 805,000 years ago