NCERT Solutions Science Chapter 17 Stars and the Solar System for Class 8th
Chapter 17 of the NCERT Science textbook for Class 8, titled “Stars and the Solar System,” explores the various celestial bodies and phenomena that make up our universe. It begins by explaining what stars are, their composition, and how they generate light and heat through nuclear fusion. The chapter highlights the importance of constellations, grouping stars into recognizable patterns that help in navigation and timekeeping.
The Solar System is then introduced, detailing the Sun as the central star and its gravitational influence on the planets, moons, asteroids, and comets. Each planet is described with unique characteristics, such as size, distance from the Sun, and atmospheric conditions. The chapter also touches on the concepts of satellites, both natural and artificial, explaining their roles and functions.
NCERT Solutions Science Chapter 17 Stars and the Solar System
Choose the correct answer in Questions 1-3.
Question 1.
Which of the following is NOT a member of the solar system?
(a) An asteroid
(b) A satellite
(c) A constellation
(d) A comet
Answer:
(c) A constellation
Question 2.
Which of the following is NOT a planet of the sun?
(a) Sirius
(b) Mercury
(c) Saturn
(d) Earth
Answer:
(a) Sirius
Question 3.
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.
Answer:
(a) we can see only that part of the moon which reflects light towards us.
Question 4.
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 ______
(e) Shooting stars are actually not _____
(f) Asteroids are found between the orbits of and ______
Answer:
(a) Neptune
(b) Mars
(c) constellation
(d) satellite
(e) stars
(f) Mars, Jupiter
Question 5.
Mark the following statements 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.
Answer:
(a) False
(b) True
(c) False
(d) True
(e) False
(f) False
Question 6.
Match items in column A with one or more items in column B.
Answer:
(i) (e) (g)
(ii) (a)
(iii) (c) (f)
(iv) (d)
Question 7.
In which part of the sky can you find Venus if it is visible as an evening star?
Answer:
In west side of the sky.
Question 8.
Name the largest planet of the solar system.
Answer:
Jupiter
Question 9.
What is a constellation? Name any two constellations.
Answer:
A group of stars which has a recognizable shape is called a constellation.
Example: Ursa Major, Orion
Question 10.
Draw sketches to show the relative positions of prominent stars in
(i) Ursa Major and
(ii) Orion
Answer:
(i) Ursa Major
(ii) Orion
Question 11.
Name two objects other than planets which are members of the solar system.
Answer:
Comets and asteroids.
Question 12.
Explain how you can locate the Pole star with the help of Ursa Major.
Answer:
Pole star can be located with the help of two stars at the end of Ursa Major. Imagine a straight line passing through these stars. Extend the imaginary line in North direction. This line is about five times the distance between two stars. A star is seen in this direction which is called Pole star.
Question 13.
Do all the stars in the sky move? Explain.
Answer:
No, all the stars do not move in the sky. Due to the rotation of the Earth on its own axis stars seem to move in the sky.
Question 14.
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?
Answer:
The stars are very far away from the Earth and it is not convenient to express such distances in kilo¬metres. Thus, such large distances are expressed in unit known as light year.
If we say that a star is eight light years away from Earth, it means that the light from star will reach the Earth in eight years.
Question 15.
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?
Answer:
Let the radius of Earth be r units.
Question 16.
Boojho made the following sketch (Fig. 17.6) of the solar system. Is the sketch correct or not, correct it.
Answer:
No, the sketch made by Boojho is not correct. The correct sketch is given below:
