TEXT BOOK EXERCISE
Write short answers to the following questions:
Q.1 How is that a star seldom finds another star near it?
OR
Why do the stars not come close to each other?
Ans.Millions of stars are wandering about in space. Most of these stars make their voyage in complete loneliness. An average star is over a million miles away Irom its nearest neighbour. So, it is very rare for a star to come near to another.
Q.2What happened when a wandering star came near to the sun?
Ans.when a wandering star came near the sun, it raised tides on the surtace of the sun creating such a huge amount on the surface of the sun that we can hardly imagine. With the passage of time, the mountain grew higher and higher .
Q.3 What happened as the star began to move away from the sun?
Ans. when the second star started moving away from our sun, its tidal pull had become so powertul that this mountain was torn to pieces. These pieces fell into space. They started moving around the sun. They are called planets and our earth is one of them.
Q.4 What are planets and how did they come into existence?
Ans: Planets are the heavenly bodies constantly revolving around a star of which once theywere part. The planets came into existence when a wandering star came near our sun. Due to the gravitational force of this star, a mountain was formed on the surface of the sun and it broke into pieces before the second star moved away again. These pieces began to revolve around the sun. They are called planets.
Q.5 Why is there no life on the stars?
Ans. The stars are collection of fires scattered through the space. They are too hot to allow lifeon them. Life cannot exist on other stars because it needs suitable physical conditions for its appearance.
Q.6Write a note on the beginning of life on the earth.
Ans. Life appeared when the temperature of the earth became moderate. It started in simple organisms. Their living power consisted in their being able to reproduce themselves before dying. Gradually life became more and more complex. Now human beings have their feelings and ambitions, their sense of beauty and religion.
Q.7Why is the universe, of which our earth Is a part, SO frightening? Give as manyreasons as you can.
Ans. We find the universe frightening because:
• We are unable to understand its immense distances.
• We cannot imagine the stretches of time.
•We cannot find any sign of life in the universe except on our earth .
•Our house is very little in space as compared to the total substances of the universe.
Q.8 What conditions are necessary for life on other heavenly bodies?
Ans.Life needs suitable physical conditions for its appearance. The most important is the temperature at which substances can exist in a liquid state, but these conditions do not exist anywhere in space except earth.