Jere Sue Browers, age 11, of Kearny, Nebr., fo her question:
How far apart are the stars?
In some areas of space, the stars are close together like crowded city dwellers. In other areas they are far apart, like people living on farms and ranches. Our star, the sun, might be called a country dweller, for it is in a part of the sky where the stars are very few and far apart. The nearest stars to our Solar System are about 26 million, million miles, or 4.3 light years away. A light year is one of the measuring rods we use to chart the vastness of space. It is the¬distance light travels in one year at a speed of some 186,000 miles a second.
Space stretches out in all directions. In estimating the distances between the stars we cannot take a flat area spreading out in one direction. We must take a volume of cubic space. Try to imagine a great sphere of space some 30 light years in diameter. Place our sun at the center of this sphere. On every side, space stretches for a distance of 15 light years or some 90 million, million miles. In this area of space around our sun, there are only about 50 stars.
Our part of the sky is very lonely indeed. If any of these stars have planets inhabited b y intelligent beings, these people would have to travel from four to 15 light years to visit their neighbors. In the more crowded areas of the sky, planet hoppers would have to travel less than one light year to visit a neighboring planet.
Some of the most crowded stars are in globular clusters. These are round, globe shaped areas where the stars are clustered thick and close. In a sphere of space about 100 light years across, there will b e tens of thousands of stars.
In the central area of 30 light years in diameter, there may be 50,000 stars, while in the same area around our sun, there are only 50 stars. About 100 of these globular clusters are visible through the telescope, and two of them can be seen with the naked eye in the skies south of the equator.
All the stars in our sky are part of our Galaxy, 6 vast wheel made from billions of stars. When we look at the Milky Way looping over the skys we are looking out across the flat surface of the Big Wheel. Our sun is about two thirds of the way from the hub of the wheel, out where the stars are sparsely scattered. Towards the center, the star population becomes denser.
About halfway to the hub, the star population is about ten times as dense as it is in our part of the heavens. At the center of the Galaxy, the population is perhaps a hundred times as dense as it is in our region of the sky. A star in that neighborhood might have several neighbors less than one light year away,