Virginia Cameron age 11, of Scarborough one_., Canada., for her question:
About how big is a star?
Anyone can see that the stars strewn across the velvety night sky come in assorted sizes. But the sky is full of tricks that fool our eyes and things are not always what they appear to be. A star may seem big and bright only because it happens to be very close to us.
Of all the stars we see, the glorious sun certainly seems to be the biggest and the brightest by far. But astronomers know better. Our sung they tell use, is just a medium star medium in size and brightness. It seems such a whopper because it is onl about 93 million miles away. Our second nearest star is some 27 million times farther out in space.
And distance makes things seem smaller. This is true on the earthy where distant mountains peep up like molehills on the horizon. It is true in the heavens where nearby stars may look bigger than small, dim stars that actually are distant giants. Our eyes cannot distinguish the assorted sizes of the stars. Astronomers figure their measurements from data gathered by telescopes and other delicate probing instruments..
The volume of a heavenly body is its size or the space it occupies. The volume of the sun is more than a million times greater than the volume of the earth. If it were hollows l million plus another l/3 million earth sized planets could be stuffed inside it. The sun may seem to be a whopping heavenly body to us, but it is merely a medium sized member of the starry galaxy.
There are dwarf stars no bigger then the earth and the other planets that orbit the sun. There are giant stars that make our sun look like a pigmy. The dwarfs even the close ones are too small for our eyes to seep and most of the giants are too far away to show us their immense sizes.
Some stars are 40 times bigger and some are 400 times bigger than the sun. The diameter of the largest known star is estimated to be 2,000 times greater than the width of the sun. Suppose this monster were to replace our sun at the center of the solar system. It would engulf all the inner planets and spread out beyond the orbit of Jupiter its glowing rim would reach to about halfway between the orbits of Saturn and Uranus.
Such a star is big enough to swallow most of our solar system. But its gases are so thin that chances area we might not know that it had swallowed our world. The little dwarf stars however, are made of heavy, condensed materials. A thimbleful of dwarf star material might equal the weight of a truckful of the earth's rocks.