Our Universe
We have all seen stars twinkling at night. Thousands and thousands of them are seen on a clear and cloudless night. They are millions and millions of kilometres away from us.
The sun is the nearest star which is 1,43 800 kilometres away. Many of the stars have their own system of planets moving around them just as there are planets around the sun. For a long time man has been observing stars and has found interesting things about them.
Apart from the stars there are other bodies in the sky which give out steady light. They are the planets. Planets do not produce any light of their own but they only reflect the sunlight.
Earth is one of the planets circling round the sun. The sun with all its planets form the solar system. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus Neptune and Pluto. Mercury is the nearest planet to the sun while Pluto is farthest away. The earth is the third planet from the sun.
Apart from planets, there are moons, moving around the planets. Like the planets the moons also reflect only the sunlight. Our earth has one moon. Saturn has nine moons and Jupiter has twelve moons.
The earth was once a large ball of burning gases. This hot cloud of gases spun around for many million years. It became slowly cooler and it hardened. It slowly became fit enough for lives to grow and flourish. The molten metals and gases are still lying in the centre of the earth. When they are able to exercise pressure to come out we have the volcanoes.
Earth is the third planet from the sun, rotating itself and moving around the sun what is known as its orbit. So also every planet has its own orbit around the sun. The earth moves around the sun at a speed of 96,000 kilometers per hour. The earth’s crest is made up of rocks.
The earth’s axis is slightly tilted. Seasons are caused by this tilting of the earth’s axis and the revolution of the earth round the sun. Seasons affect the lives of plants, animals and men.
