Karen Studenberg, age 12, of Eugene, Oregon, for her question:

What is beyond the Solar System?

The Solar System is our particular home in the heavens, a sort of local backyard in the endless universe. There was a time when people thought that our little Earth was the center of everything. Now we know better. And if it's too soon to plan a real voyage beyond the Solar System, at least we can let our minds imagine what such a space voyage would be like.

The sun and its family swirl around like a flattish saucer. To leave it behind, we could take off in the direction of the North Pole or the South Pole. Or we could travel outward from the equator in the direction of the other orbiting planets. In this case, we would travel some 4,000 million miles before the last of the Solar System is left behind us. On the way, we cross the orbits of Mars and giant Jupiter, ringed Saturn and Uranus, Neptune and little Pluto.

So far, we were traveling through interplanetary space. With Pluto behind us, we are really out in outer space, or interstellar space. Actually we are out among the 100 billion stars that populate our vast cart wheeling galaxy. Most likely we would prefer to make for the nearest star hoping that it too may be the parent of a planetary family. If we head in the right direction, our destination is about 27 million million miles toward the constellation Centaurus, near where we see the Southern Cross in the skies of Earth. Alpha Centauri, the sun's nearest neighbor, is a trio of three fairly close stars. We cannot say as yet whether any or all of them have planets.

If we continue our voyage toward the Milky Way, we would find more stars, closer together. However, all of them are many millions of miles apart. Now suppose we wanted to take a quick dash across the very center of the Milky Way galaxy. Even if we zoomed along at the speed of light, which is 186,000 miles per second, it would take us 100,000 years to cross from side to side.

Let's suppose we could make this impossible trip. The next step would be to leave our galaxy behind and explore the vast oceans of space that surround it. A light year is the distance that light travels in one earth year. If we take the right direction at the speed of light, after about 80,000 years we reach the Magellanic Clouds, two smallish galaxies seen in the earth's southern skies.

After traveling 100,000 or so light years across intergalactic space, we might come to the Great Nebula in Orion. This starry wonder is a sort of twin to our galaxy. If we have the time, we may find a group of other galaxies in this cosmic neighborhood. But sooner or later we would be tempted to voyage on and on through outer space.

Would we ever come to the end of the vast universe? As far as anybody knows, we would not. The universe that stretches beyond our Solar System goes on forever and ever. And in all directions, its vast oceans of space are strewn with thousands upon thousands of widely scattered, star studded galaxies. Wow!