NCERT Solutions for Class 8 Science, Chapter 17 - Stars And The Solar System

The NCERT Class 8 Science, Chapter 17 deals with our solar system and the stars. Stars are the celestial bodies that emit light of their own. Our sun is also a star. All-natural bodies visible in the sky, outside the Earth’s atmosphere, constitute the celestial bodies, e.g. stars, planets, their moons, comets, meteors, etc. The Moon is the celestial body closest to us. As you move further in this chapter you will study the solar system which is formed by the sun and the celestial bodies that revolve around it. The sun is the source of almost all energy on Earth. Later on, you will learn some other member in our solar system like asteroids (rocky planetary bits orbiting around the sun), comets (celestial bodies that revolve around the sun), meteors and meteorites (chunks of rock or particles of debris in our solar system) and satellites (a body revolving around another body). At the end of this chapter, the concept of stars and constellations will be discussed.

To know more about NCERT Solutions for Class 8, Science Chapter 17 – Stars and The Solar System, let’s look at the topics and sub-topics of this chapter :

17.1 The Moon

17.2 The Stars

17.3 Constellations

17.4 The Solar System

17.5 Some Other Members Of The Solar System

In Class 8 Science Chapter 17, you will learn-

Section 17.1 - In this section, you will study the Moon. The Moon is the celestial body closest to us. It is the only natural satellite of the Earth. It is a non-luminous body and it reflects the sunlight incident on it. Due to its revolution around the Earth, when it is at different positions in its path, the apparent disc of the Moon changes, which gives rise to its phases. The various shapes of the bright part of the moon as seen during a month are called phases of the moon. The Moon is a fascinating object for poets and story-tellers. But when astronauts landed on the moon, they found that the moon’s surface is dusty and barren. There are many craters of different sizes. It also has a large number of steep and high mountains. Some of these areas high as the highest mountains on Earth.

Section 17.2 - This section will teach you about the stars. Stars are the celestial bodies that emit light of their own. Our sun is also a star. It is convenient to express distances of stars in light-years.  A light-year is a distance covered by light in one year. Further, you will study the appearance of the stars. Star appears to move from east to west. The pole star appears to be stationary from the Earth because it is situated close to the direction of the axis of rotation of the Earth. Many of the stars that we see in the sky are much bigger than the sun. But as they are quite far away from us, they appear very small.

Section 17.3 - This section deals with the concept of constellations. Constellations were devised by ancient people to be able to recognise stars in the sky. The shapes of constellations resemble objects familiar to those people. A group of stars forming some kind of recognisable figures or patterns are known as constellations. They appear to move from east to west as Earth rotates from west to east. Orion – the Hunter, Ursa Major – the Great Bear or Saptarishi, Cassiopeia are some constellations.

Section 17.4 - You have already studied the moon, stars and constellations. Now you will study the solar system. The Sun and the celestial bodies that revolve around it form the solar system. It comprises a large number of bodies like planets, their moons, comets, asteroids, meteoroids, meteors and meteorites. These objects are held together in the solar system due to Sun’s gravitational pull. As you move further in this section you will learn the members of the solar family like the sun, the planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune).

Section 17.5 - Towards the end of this chapter, this section will brief you about some other members of the solar system – Asteroids, Comets, Meteors and Meteorites, Satellites.  Asteroids are rocky planetary bits orbiting around the sun. Comets are the celestial bodies that revolve around the sun. Meteorites are chunks of rock or particles of debris in our solar system. They are smaller than comets. When meteorites enter the Earth’s atmosphere they are called meteors. Most meteors burn up in the atmosphere. Satellites are said to be a body revolving around another body. Moon is a natural satellite of the Earth. Some planets also have natural satellites. IRS, EDUSAT, INSAR are examples of artificial satellites. They are used for weather forecasting, long-distance communication and remote sensing.

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