Tony Quon, age 10, of Victoria, B.C., for his question:

Which star is nearest to our sun?

The space between the stars is so vast that we cannot measure it in ordinary miles. A million miles is such a little distance in the skies it takes us nowhere at all. So the distances between us and the stars are usually measured in light years:

A light year is the distance which light travels in one year and the speed of light is about 186,000 miles a second. One light year is equal to more than six million, million miles. The nearest star is 4.3 light years away. To reach it we would have to travel about 26 million, million miles, That is 26 followed by twelve.

The size of the stars and the vastness of spats` are difficult facts for our minds to grasp. Sometimes it helps to understand something very big if we first shrink it down to something very small. This mental exercise loosens up the old thinking machine.

If our sun were hollow, a million earth sized planets could get inside it and still have plenty of room to romp around. Just for fun, let's scale the big sun down to the size of the dot at the end of this sentence. On the same scale, its nearest neighbor would also be a dot  about five miles away. The stars are actually very big, but they are far, far apart in the vast oceans of space,

We cannot measure star distances from the sun because we are almost 93 million miles away. True, this is a very short hop in sky distances and it does not make much difference whether we are seeking the star nearest to us or t o the sun. It will be the same star, though we measure its distance from the earth, .

The nearest neighbor to us and the sun is most likely in the constellation Centaurus, the Centaur. Alpha Centaurs, the brightest star in this group, is really a double star  two stars very close together. We know that Alpha Centaurs is 4.3 light years from us. But there is a dimmer star in the same group which may be even closer. Its name is Proxima.  There may be other dim stars in 'the sky which are closer still. But so far as we know now, the stars closest to us and our sun are Alpha Centaurs and Proxima,

The constellation Centauris is seen in the sky south of the equator. So we cannot go out tonight and look at our next door neighbors in the heavens. The nearest star seen north of the equator is Sirius, the Dog Star. This brilliant star is 8.6 light years away  more than 50 million, million miles.

Let's imagine that we could travel at the speed of light. If we stayed on courses we could reach either Alpha Centaurs or Proxima in about four years and four months. It would take us more than eight and a half years to reach the brilliant Dog Star.