Beyond Earth — Class 6 Science
Curiosity · Chapter 12
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5- Mathematics
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- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
Chapter summary
Key ideas & terms
- Star
- A heavenly body that shines with its own light, such as the Sun, which is the star nearest to us.
- Constellation
- A defined region of the sky that often includes a recognisable pattern of stars; the sky is divided into 88 such regions.
- Pole Star
- The star Polaris, part of the Little Dipper, which appears nearly stationary in the north and helps locate the north direction.
- Planet
- A large, nearly spherical object that revolves around the Sun; the eight planets range from Mercury to Neptune.
- Satellite
- An object that moves around a planet; the Moon is the Earth's natural satellite.
- Solar System
- The Sun together with the eight planets, their moons, and smaller objects such as asteroids and comets that move around it.
Extra questions & answers
What is a star?
A star is a heavenly body that shines with its own light; the Sun is the star nearest to us.
What is a constellation?
A constellation is a defined region of the sky that often includes a recognisable pattern of stars; the sky is divided into 88 constellations.
Why is the Pole Star important?
The Pole Star appears nearly stationary in the north direction, which helps people locate the north direction in the Northern hemisphere.
What is the Sun, and roughly how far and how big is it?
The Sun is a star — a hot ball of gases — about 100 times bigger than the Earth in diameter and about 150 million km (one astronomical unit) away, and the main source of light and heat.
What is a planet?
A planet is a large, nearly spherical object that revolves around the Sun, such as our Earth.
Name the eight planets in order of increasing distance from the Sun.
In order of increasing distance, the eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
How do the inner and outer planets differ?
The four inner planets — Mercury, Venus, Earth, and Mars — are smaller with solid rocky surfaces, while the four outer planets are much larger, mostly gas and ice, with ring-like structures.
What is a satellite, and what is the Earth's natural satellite?
A satellite is an object that moves around a planet; the Earth's natural satellite is the Moon, which takes about 27 days to revolve around the Earth.
What are asteroids and comets?
Asteroids are small rocky, irregular objects mostly revolving in a belt between Mars and Jupiter, while comets are icy-rocky objects with long tails that form as they approach the Sun.
What together forms the Solar System, and where does it lie?
The Sun, the eight planets, their moons, and smaller objects such as asteroids and comets together form the Solar System, which lies within the Milky Way Galaxy.
Let us enhance our learning
1. Match the column: (i) Satellite of Earth
(d) Moon — The Moon is the natural satellite that revolves around the Earth, completing one revolution in about
1. Match the column: (ii) Red planet
(c) Mars — Mars is called the Red Planet because its surface soil and rocks contain iron oxide which gives it a reddish appearance.
1. Match the column: (iii) Constellation
(a) Orion — Orion is a well-known constellation that looks like a hunter with three bright stars forming its belt.
1. Match the column: (iv) Planet which is commonly called an evening star
(b) Venus — Venus appears very bright in the western sky after sunset and in the eastern sky before sunrise, so it is called the Morning Star or Evening Star, though it is a planet not a star.
2. (i) Solve the following riddle. My first alphabet is in MAN but not in CAN My second alphabet is in ACE and also in FAN My third alphabet is in RAT and not in CAT My fourth alphabet is in SUN but not in FUN I am a planet that moves around the Sun.
The answer is MARS. First letter M is in MAN but not in CAN, second letter A is common to ACE and FAN, third letter R is in RAT but not in CAT, and fourth letter S is in SUN but not in FUN. MARS is the fourth planet from the Sun and is known as the Red Planet.
2. (ii) Make two similar riddles by yourself.
Riddle 1 for VENUS: My first letter is in VAN but not in CAN, my second is in EAT and also in EGG, my third is in NET but not in NOT, my fourth is in USE but not in BUS, my fifth is in SUN but not in FUN. I shine brightest after the Sun and Moon. Answer is VENUS. Riddle 2 for EARTH: My first letter is in EAT but not in AT, my second is in ART and also in ARE, my third is in RAT but not in CAT, my fourth is in TEN but not in TIN, my fifth is in HAT but not in HOT. I am the Blue Planet where life exists. Answer is EARTH.
3. Which of the following is not a member of our Solar System? (i) Sirius (ii) Comets (iii) Asteroids (iv) Pluto
(i) Sirius is not a member of our Solar System. Sirius is a star in the constellation Canis Major and is the brightest star in the night sky, located far outside the Solar System. Comets, asteroids and Pluto (a dwarf planet) all revolve around the Sun and are members of the Solar System.
4. Which of the following is not a planet of the Sun? (i) Jupiter (ii) Pluto (iii) Neptune (iv) Saturn
(ii) Pluto is not considered a planet of the Sun now. According to the International Astronomical Union definition in
5. Which is the brighter star, the Pole Star or Sirius?
Sirius is the brighter star. Sirius, in the constellation Canis Major, is the brightest star seen in the night sky, while the Pole Star (Polaris or Dhruva tara) is a much dimmer star, though it is important because it appears almost stationary in the north direction.
6. An artist’s representation of the Solar System is given in Fig. 12.12. Is the order of the planets correct? If not, write the correct order in the boxes in the figure.
No, the order shown in Fig. 12.12 is not correct. The planets are not in the correct increasing order of distance from the Sun. The correct order from the Sun outward is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. The asteroid belt lies between Mars and Jupiter.
7. A portion of night sky with stars is shown in Fig. 12.13. Look carefully and identify the groups of stars that form the patterns—the Big Dipper and the Little Dipper. Draw lines to connect the stars for these patterns and label them. Also, identify and label the Pole Star. You may refer to Fig. 12.4 for help.
In Fig. 12.13 the seven bright stars that form a shape like a ladle or a question mark is the Big Dipper, which is part of the constellation Ursa Major and also called Saptaṛṣi. The smaller, fainter ladle-shaped pattern with seven stars is the Little Dipper, which is part of Ursa Minor. The star at the tip of the Little Dipper’s handle is the Pole Star (Polaris or Dhruva tara). To find it, join the two end stars of the Big Dipper’s cup and extend the line about five times the distance between them towards the north to reach the Pole Star.
8. A portion of the night sky is shown in Fig. 12.14. Draw lines to connect the stars for Orion and label the star Sirius. You may refer to Fig. 12.3.
Orion is identified by its seven to eight bright stars forming the shape of a hunter, with three bright stars in a short straight line in the middle forming the hunter’s belt. Once that belt is found, the rest of Orion’s outline can be joined. Sirius is the very bright star located to the southeast of Orion. If you extend an imaginary line through the three belt stars of Orion towards the east, the bright star that meets that line is Sirius in Canis Major.
9. From Earth, you can see stars fading away at dawn and appearing at dusk. During the day we do not see the stars. Explain why.
Stars are present in the sky during the day as well, but we cannot see them because the Sun is extremely bright. Its light scatters in the atmosphere and makes the sky so bright that the faint light from distant stars is washed out. At dawn the sky gradually brightens so stars fade, and at dusk the sky darkens so stars become visible again. Stars shine with their own light but are much farther than the Sun, so they appear as dim points compared to the Sun’s glare.
10. During a clear night, try to observe the Big Dipper 3–4 times at an interval of 2 to 3 hours. Also try to locate the Pole Star each time. Does the Big Dipper appear to move? Draw a rough sketch to illustrate this, mentioning the time in each case.
Yes, the Big Dipper appears to move slowly around the Pole Star during the night, while the Pole Star stays almost in the same position in the north. This apparent motion is due to the rotation of the Earth on its axis. If you observe at about
11. Think about the night sky and write a poem or a story on it.
A fresh example: Night Sky — In Nubra’s dark the sky is deep, A blanket where the starlights peep, The Dipper lifts its shining ladle, Orion hunts with belt and cradle, The Pole Star holds the north so true, And Sirius sparkles bright for you, Millions of suns in Milky Way, Remind us how small we are each day. This poem uses the constellations and ideas from the chapter to express the beauty and wonder of the night sky.