We cannot live at all without the sun. The sun gives us light and heat, and without it there could be no life. If the sun went out, it would always be night and we should be in dense darkness. If the sun went out, the cold would be intense, and the earth would be covered all over with ice and snow, as it is at the North Pole. If the sun went out, all plants and animals and men would die. No wonder in old times people worshipped the sun!
And yet we could not bear the sun all the time. If the sun remained in the sky always and there was never any night, the earth would become so hot that we could not live on it. But we see the sun only part of the day, and for the rest of twenty-four hours, it is hidden from us. We see it rise in the east, and the night comes to an end; it climbs up the sky, until at noon it is right over our heads; and then it sinks down in the west, and sets and the night comes again. It, therefore, looks as if the sun is always moving round the earth; and, in old times, people believed that the earth was standing still and the sun was going round it. But we know that this was a mistake. When we are travelling in a train, it looks as though the trees and telegraph poles are running backward past us: but we know they are really standing still, while we are moving forward in the train. So it is with the sun and the earth. The sun does not move; but the earth on which we live is always turning round on itself like a spinning ball, and it is our movement that makes the sun seems to move.
What is the sun? It is a huge mass of flaming gas, so big that it could easily swallow up hundreds of earth-like ours. It looks small because it is so far away-ninety-three million miles! The stars we see in the sky at night are really suns, some of them much bigger than our sun, but they are so much farther away from that they seem to be only little points of light. So the sun is really a small star, and the stars are big suns.
A few of the stars we see in the sky are really bodies like our earth and, like the earth, go round the sun. So the sun is like the father of a family, with its children (called the planets) moving round it.