question_answer 3)

1.(b) What is meant by the "solar system"? (c) Name all the planets according to their distance from the sun. (d) Why is the Earth called a unique planet? (e) Why do we see only one side of the moon always? (f) What is the universe?

Answer:

(b).The sun and nine planets which revolve around make a family of sun or solar system. There are 44 satellites in solar system. (c) The planets according to their distance from the sun are : Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. (d) The earth is a small member of the Solar System. It is the fifth in size of nine major planets and third in distance. But it has unique poosition in Solar System. (e)The moon revolves round me earth in about 27 days and 8 hours. It takes exactly the same time in completing one rotation about its axis. As such we always see only one side oof the moon while the other side always remains away from us. (f)The Universe is the whole body of stars, planets, satellites and gases. It is endless. Stars are huge bodies of glowing gases e.g. sun. Planets and satellites do not have heat and light of their own. They are lit by the light of the stars.