Cheryl Slood, age 9, of Elizabethtown, Penn.
How big are the stars?
On a clear night, we can see about 2,000 stars. We see big ones and bright ones,, small ones and dim ones. But when it comes to Judging the size of a star, we cannot quite trust our eyes. For faraway things tend to look smaller and bright things tend to dim with distance. It is no easy job to measure the size of a star, but the astronomers can tell us the true size of many of them. The stars, we are told, do come in assorted sizes. There are huge giants, little dwarfs and many medium sized stars.
Our sun is a medium sized star, It looks bigger and brighter than anything else in the sky because it is only about 92 million miles away, Our own private star is big enough to gobble up the whole world a million times and still have room for dessert. This is the volume of the sun, the amount of space it occupies, As a rule, however, the size of a star is measured by its diameter. This is a line straight through the middle from side to side.
The diameter of the earth is a little less than 8,000 miles. The diameter of the sun is 860,000 miles. And the Bunts diameter is used as a unit for measuring the size of bigger stars. If you tend to watch the skies, you have no doubt seen a star with a diameter 30 times wider than the sun, another 72 times wider and another 390 times wider. The biggest star measured so far has a diameter 2,000 times wider than that of the sun. At the other end of the scale, there are dwarf stars no bigger than our own little planet.
Find the Big Dipper and trace the arc along the handle. Carry this line on over the sky and you will come to a big red star called Arcturus, This fellow is 30 times bigger than the sun.
Find the constellation Scorpius, the Scorpion, sprawled low in the western sky. At the heart of the Scorpion is Antares, a giant red star 400 times bigger than the sun. The big red star in Taurus, the Bull, is Aldebaran, 72 times bigger than the sun.
Certain dwarf stars are much nearer than these giants, but all of them are too small for our eyes to see. However, our minds can grasp the idea of a planet‑sized star. It is harder to grasp the size of the average stars which are a million or more times as big as our world. It is almost impossible to imagine the size of some of the red giants. A space ship traveling at 1,000 miles an hour would take more than a month to travel the diameter of the sun, three years to cross Arcturus and 30 years to cross Antares,
Imagine the Solar System if the red giant Antares were to replace our medium sized sun. The big star would spread out beyond the orbit of Mercury and beyond the orbit of Venus, Our world would be inside it, for the great giant would sprawl out beyond our orbit and even farther out, beyond the orbit of Mars.