Important Questions for CBSE Class 8 Science Chapter 17 - Stars and The Solar System

Very Short Answer Questions: 1 Marks

1. Which one of the following is a star? 

a. Sun 

b. Moon 

c. Earth 

d. Venus

Ans: a. Sun 

2. _______________ is a constellation which looks like a distorted letter W or M. 

a. Orion 

b. Great Bear 

c. Cassiopeia 

d. Leo major

Ans: c. Cassiopeia 

3. Which one of the following is a natural satellite of the earth? 

a. Venus 

b. Mercury 

c. Sun 

d. Moon

Ans: d. Moon

4. Which one of the following statements is false about Uranus? 

a. Uranus is the innermost planet of the solar system. 

b. Uranus also rotates from east to west. 

c. Uranus has a highly tilted rotation axis. 

d. Uranus can be seen only with the help of large telescopes.

Ans: a. Uranus is the innermost planet of the solar system. 

5. Artificial satellites are used for _________________. 

a. weather forecasting 

b. remote sensing 

c. transmitting radio signals 

d. all of these

Ans: d. All of these

6. __________ is the source of almost all energy on the Earth. 

a. Satellites 

b. Stars 

c. Sun 

d. Moon

Ans: c. Sun 

7. The gap between the orbit of mars and Jupiter is ______________. 

a. meteorite 

b. meteor 

c. asteroid 

d. comet

Ans: c. asteroid 

8. The study of celestial objects and associated phenomena is called ____________.

Ans: Astronomy.

9. After the full moon day, the sunlit part of the moon is visible from the Earth ___________ in size every day.

Ans: Decreases

10. Which is the brightest star in the sky?

Ans: Sirius

11. What is the distance of the Sun from the Earth?

Ans: 8 Light Minutes

12. Stars appear to move from ____________ to __________.

Ans: East to West

13. Define constellations.

Ans: The group/cluster of star forming a particular shape is called a constellation

14. _____________ is another prominent constellation in the northern sky.

Ans: Cassiopeia

15. What helped our ancestors to devise calendars and almanacs?

Ans: Passage of sun, star, planet and moon.

16. Name the planet which is denser than water.

Ans: Saturn

17. What is a satellite?

Ans: Any celestial body revolving around a plant is called its satellite.

18. It is convenient to express the distances of stars in _______________.

Ans: Light Years

19. _______________landed on the moon for the first time.

Ans: Neil Armstrong

20. Name the comet which appears after every 76 years?

Ans: Halley’s Comet.

21. Which planet is also known as Brihaspati?

Ans: Jupiter

22. Plant which takes the longest to go around the sun?

Ans: Neptune

Short Answer Questions: 3 Marks

23. Identify the constellations given below.

Ans: a. Great Bear b. Cassiopeia c. Orion

24. Write a short note on Ursa Major.

Ans: Ursa Major is one of the constellations seen in the night sky. It is also known as Big Dipper, The Great Bear or Saptarishi. This constellation consists of seven prominent stars. This constellation helps to locate the Pole star. 

25. Why do you think phases of the moon are important in our social life?

Ans: The phases of the moon are significant in our social lives since most Indian festivals are held in accordance with the moon's phases. Diwali, for example, falls on the new moon day, whereas Budh Poornima and Guru Nanak's birthday fall on the full moon day. On the thirteenth night of the waning moon, Maha Shivratri is observed. Eid Ul-Fitr is celebrated on the day after the crescent moon is seen. Not just the festivals, many people in ayurveda relate the phases of the moon with human health.

26. Briefly describe the surface of the moon.

Ans: The moon's surface is dusty and barren. There are several craters of various sizes. There are several steep and high mountains in the area. Some of them are as tall as the world's highest mountains.

27. Define the following terms. 

a. Orbit: A planet has a definite path in which it revolves around the Sun. This path is called an orbit.

b. Period of revolution: The time taken by a planet to complete one revolution is called its period of revolution.

28. Correct the following statements. 

a. The moon has different layers of atmosphere and has no water. 

Ans: The moon has no atmosphere as well as no water.

b. Stars do not emit light of their own.

Ans: Stars emit their own light and shine bright in the night sky.

29. Why does the pole star appear to be stationary from the Earth?

Ans: From every location on the planet, the pole stars appear to be stationary. This is due to the fact that it is located on a line parallel to the earth's axis of rotation. Pole star is located in the north. Hence when we see the pole star straight above us, and it appears to be stationary.

30. Write a short note on comets.

Ans: Comets are one of the members of our solar system. They have tremendously elliptic orbits around the Sun. Their time of revolution around the Sun, on the other hand, is usually quite long. A comet is characterised by a luminous head and a long tail. As it gets closer to the sun, the length of the tail lengthens. A comet's tail is always pointed away from the sun.

31. What do you know about ‘Mangalyaan’?

Ans: ISRO launched India's first interplanetary mission, Mangalyaan. After Roscosmos, NASA, and the European Space Agency, India became the first Asian country and the fourth in the world to reach the planet. On September 24, 2014, it was successfully deployed into a Mars orbit. With this, India became the first country in the world to accomplish this goal on its first try.

32. Give any four examples of artificial satellites.

Ans: Some of the Indian artificial satellites are as follows:

1. IRS-1B (1991)

2. INSAT-2DT (1992)

3.  INSAT-2A (1992)

4. Mars Orbiter Mission (2013)

5. Chandrayaan-2 (2019)

33. Explain the arrangement of stars in the Orion constellation.

Ans: Orion is a well-known constellation that can be seen all throughout the world because it is placed on the celestial equator. It consists of seven bright stars. Hunter is another name for Orion. Three stars in the middle form a belt and four bright stars appear to be in a quadrilateral formation.

34. Write the names of eight planets in their order of distance from the Sun.

Ans: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

35. What are asteroids, meteors and meteorites?

Ans: 

Asteroids: A huge number of tiny objects that spin around the Sun occupy the space between Mars and Jupiter's orbits, which is known as the asteroid belt.

Meteors and Meteorites: A meteor is a tiny object that reaches the earth's atmosphere on rare occasions. It has a very fast speed at the time of entering the earth. The friction caused by the atmosphere causes it to heat up. It shines brightly and quickly dissipates. Some meteors are large enough to reach Earth before entirely dissipating. A meteorite is a body that lands on the Earth. It gives a large surrounding area.

Long Answer Questions: 5 Marks

36. Explain the phases of the Moon.

Ans: The full moon day is the day when the entire disc of the moon is visible. Every night following that, the size of the bright section of the moon appears to get smaller and smaller. The moon is not visible on the fifteenth day. The ‘new moon day' is celebrated on this day. The day after the new moon, only a small part of the moon is visible in the sky. This is known as the crescent moon. The moon slowly gets bigger every day. We obtain another full view of the moon on the fifteenth day. The various shapes of the bright part of the moon as seen during a month are called phases of the moon.

37. Sketch a simple diagram of positions of the moon in its orbit and its corresponding phases.

Ans: 

38. Demonstrate an activity to show that a pole star can be located with the help of Ursa Major.

Ans: This activity should be performed on a clear moonless night during summer at about 9.00 pm.

• Look towards the northern part of the sky and identify Ursa Major.

• Look at the two stars at the end of Ursa Major.

• Imagine a straight line passing through these stars.

• Extend this imaginary line towards the north direction.

• This line will lead to a star which is shining bright. This is the Pole Star

39. What is a solar system? Explain characteristics of any two planets in the solar system.

Ans: The Sun, eight planets and their moons, comets, asteroids, meteoroids, and dwarf planets make up a solar system, which revolves around it. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune are the eight planets that revolve around the Sun in given order. Between Mars and Jupiter, an asteroid belt exists. These planets revolve around the Sun in an elliptical orbit.

Characteristics of Earth:

• It is the third planet in the solar system.

• It is also known as a blue plant due to the presence of water.

• It revolves around the sun for 365 days and 4 hours.

• It rotates around its own axis in 24 hours.

• It has one natural satellite known as the moon.

Characteristics of Mars:

• It is the fourth planet in the solar system.

• It is also known as the red planet due to the presence of red dust.

• Mars is much colder than earth.

• Its diameter is approximately half of earth’s diameter.

• Mars has two natural satellites known as Phobos and Deimos.