20 – In the World of Stars
Q 1.
Fill in the blanks with appropriate word given in brackets :
(1)
When seen from a great distance, the sky seems to be touching the ground along
a
circle.
This circle is called the ………………..
(2)
The ......................... is used while defining the zodiac signs.
(3)
Classified according to seasons, one season will have…………….. nakshatras.
(4)
The rising of the sun in the east and its setting in the west is the………….... motion of the sun
Ans. (1) horizon (2) ecliptic (3) nine (4)
apparent
Q. 2.
Answer the following:
(1) A
star rises at 8 pm tonight, at what time will it rise after a month? Why?
Ans.
The stars rise 4 minutes early every next day. Therefore, after a month it will
be 120 minutes or 2 hours earlier than tonight. Thus, the star will rise at 6
pm after a month.
(2)
What is meant by 'the sun enters nakshatra'? It is said that in rainy season
sun enters Mrug nakshatra. What does it mean?
Ans.
As the earth changes its position due to its revolution, a different
constellation or raashi appears behind the sun every 13° 20'. But this is
expressed as if sun has entered a particular raashi. So, when we say sun has
entered Mrug nakshatra, actually Mrug constellation is behind the sun.
(3)
What is a constellation?
Ans. A
group of stars occupying a small portion of celestial sphere is called a
constellation. Some of these stars appear to form certain animal or human
figures and objects. These constellations are known by the brightest star
present in it.
(4)
Write a paragraph on birth and lifecycle of a star using figure on page 201.
Ans.
The stars are born out of nebulae which are the clouds of hydrogen gas and dust
particles. In the nebulae there are particles that are attracted towards one
another due to the force of gravity. This makes contractions in the clouds
resulting into denser and spherical bodies. At the same time, at the core of
clouds the pressure of the gas increases. This causes rise in the temperature
to tremendous extent. The energy is generated due to this condition. This
spherical cloud of hydrogen is called a 'star'.
The
processes such as contraction, expansion, rise in temperature, etc. bring about
changes in the nature of the star eventually. These changes are very gradual
and spread over a very long period of time. They constitute the lifecycle of
stars. Astronomers identify these different forms of the stars at various
stages during their lifecycle. They are then named with some identity.
(5) Is it wrong to say that planets, stars and
nakshatras affect human life? why?
Ans.
Distant stars, planets, comets or any constellation do not have any influence
on human life. In the age of scientific and technological progress, man has
stepped over the moon. Soon in this century man will step on the Mars too.
Therefore, unless it is scientifically proved, we cannot say that stars,
planets and celestial bodies have impact on human life.
