STARS AND THE SOLAR SYSTEM

Explain with a diagram how you can locate pole star with the
help of the constellation Great Bear (Ursa Major).

Suppose the distance between earth and sun becomes half of its
present distance. What is likely to happen to life?

Suppose the moon emits light of its own. Would it still have
phases? Justify your answer.

Paheli saw the moon through a glass window at 8:00 p.m. She
marked the position of the moon on the glass pane. She got up
at 4 a.m. in the morning. Will the moon be visible at the same
position?

Why does the moon change its shape daily?

Meteors are not visible during the daytime. Explain the reason.

Meteors are not visible during the daytime. Explain the reason.

A star is ten light years away from the earth. Suppose it brightens
up suddenly today. After how much time shall we see this change?

John saw full moon on a particular day. After how many days
will he be able to see the full moon again?

State whether the following statements are ‘True’ or ‘False’.
(a) The planet nearest to us is Jupiter.
(b) All the stars are at the same distance from us.
(c) The planets do not emit light of their own.
(d) The planets keep changing their position with respect to stars.
(e) The planet Venus appears in the eastern sky before sunrise.
(f) The plane in which the earth revolves around the sun is called
equatorial plane of earth.

Paheli and Boojho observe a bright object in the night sky which
was not twinkling. Paheli says, it is a star and Boojho says it is a
planet. Who is correct?

Do stars emit light only during night?

Boojho made the following sketch (Fig. 17.29) of the solar system. Is the sketch correct? If not, correct it.

Fig. 17.29

The radius of Jupiter is 11 times the radius of the Earth. Calculate the ratio of the volumes of Jupiter and the Earth. How many Earths can Jupiter accommodate?

Why is the distance between stars expressed in light years? What do you understand by the statement that a star is eight light years away from the Earth?

Do all the stars in the sky move? Explain.

Explain how you can locate the Pole Star with the help of Ursa Major.

Name two objects other than planets which are members of the solar system.

Draw sketches to show the relative position of prominent stars in (a) Ursa Major and (b) Orion

What is a constellation? Name any two constellations.

Name the largest planet of the solar system.

In which part of the sky can you find Venus if it is visible as an evening star?

Match items in column A with one or more items in column B.

Mark the following statement as true (T) or false (F).

(a) Pole star is a member of the solar system. ( )

(b) Mercury is the smallest planet of the solar system. ( )

(c) Uranus is the farthest planet in the solar system. ( )

(d) INSAT is an artificial satellite. ( )

(e) There are nine planets in the solar system. ( )

(f) Constellation Orion can be seen only with a telescope. ( )

Fill in the blanks:

(a) The planet which is farthest from the sun is _________.

(b) The planet which appears reddish in colour is _________.

(c) A group of stars that appear to form a pattern in the sky is known as a __ _________.

(d) A celestial body that revolves around a planet is known as a_________.

(e) Shooting stars are actually not _________.

(f) Asteroids are found between the orbits of ________ __ and _________.

Phases of the moon occur because

(a) we can see only that part of the moon which reflects light towards us.

(b) our distance from the moon keeps changing.

(c) the shadow of the Earth covers only a part of the moon's surface.

(d) the thickness of the moon's atmosphere is not constant.

Which of the following is NOT a planet of the sun?

(a) Sirius

(b) Mercury

(c) Saturn

(d) Earth

Which of the following is NOT a member of the solar system?

(a) An asteroid

(b) A satellite

(c) A constellation

(d) A comet