1. (c) A constellation
2. (a) Sirius
3. (a) We can see only that part of the moon which reflects light towards us.
4. Fill in the blanks.
(a) The planet which is farthest from the Sun is Neptune.
(b) The planet which appears reddish in colour is Mars.
(c) A group of stars, which appear to form a pattern in the sky is known a constellation.
(d) A celestial body that revolves around a planet is known as satellite.
(e) Shooting stars are actually not stars.
(f) Asteroids are found between the orbits of Mars and Jupiter.
6. Match the following
7. Venus appears in the western sky just after sunset.
8. Jupiter is the largest planet of the solar system.
9. The stars forming a group that has a recognizable shape is called constellation.
11. Satellites and asteroids are the objects that are the members of solar system.
12. To locate the Pole Star we should look towards the northern part of the sky and identify Ursa Major. We may look at the two stars at the end of Ursa Major. A straight line passing through these stars is imagined and is extended towards the north This line leads to a star which is not too bright. This is the Pole Star.
13. No, no star moves in sky. They appear to move from east to west, because the Earth rotates from west to east about its axis.
14. The distance of stars is so large that it cannot be expressed in terms of kilometer. That is why very large distances are expressed in another unit known as light year. One light year is the distance travelled by light in one year.
15. If the distance of a star is eight light years, it means that this distance is the distance travelled by light in one year.
If the radius of the Earth is r.
Then, radius of the Jupiter is 11r.
So, ratio of the volumes of Jupiter and Earth = 4/3 π (11r)3 /4/3 πr3 = 1331:1
So, 1331 Earth can accommodate within the Jupiter.
16. The positions of Mars and Venus should be interchanged. Similarly positions of Neptune and Uranus should be also interchanged.