The people who study stars are called astronomers. About 1,500 years ago, there lived an astronomer in our country. His name was Aryabhatta. He studied and thought astronomy and mathematics. He was the first man to tell us that the earth is round and it rotates on its own axis.
He also told us that the moon is dark and it shines only when sunlight falls on it.
Varahamihira was another astronomer. He wrote many books. Bhasker discovered a method of finding out the motion of plants.
Sawai Jai Singh, the king of Amer was also a great lover of astronomy. He built Jantar Mantar to study the position of stars and to measure time.
Stars
Besides moon, we see a large number of stars in the sky at night. The stars are very big heavenly bodies. The stars remain fixed at one place. The stars give their own light. The stars are father away than the sun. All the stars are not alike. Some of them are bigger than the others. Some are bright while others are dim. The stars seem to twinkle because of the presence of atmosphere round the earth. Do you know why the stars look small? The stars are very far away from the earth. That is why they look small. If you see the sky carefully, we observe that some stars occur in groups. There are a number of groups of stars in sky.
Each group of stars is called a constellation. The groups of stars form some interesting shapes.
We can see a group of seven stars called saptarishi in the sky. In the north, you can see a very bright star called the pole star. The position of people star helps in finding out the north direction.
Universe: - it seems to be expanding like a balloon being blown up.
Galaxy: - the irregular luminous band of stars, gas, dusts, etc, existing in space.
Orbit:-the path of one heavenly body as it travels around another.
Solar system: - a star, its planets with their satellites.
Star: - a heavenly body that produces its own heat and light.
Eclipse: - the partial or complete hiding of one heavenly body because of the shadow of another falls on it.
Moon: - a natural body that orbits a planet.
Satellite: - any natural or man –made body that orbits a heavenly body