Beyond the Earth Notes

Beyond the Earth lies a vast and mysterious cosmos that has fascinated humanity for centuries. From the glowing stars scattered across the night sky to the distant galaxies billions of light-years away, space represents both our greatest curiosity and our greatest frontier. As technology advances, we are no longer limited to observing the universe from our planet—we are beginning to explore it first-hand. Space missions, powerful telescopes, and scientific discoveries have opened new doors to understanding how the universe works and what our place in it may be. Exploring beyond the Earth not only reveals the wonders of space, but also inspires new questions, new possibilities, and the hope of uncovering worlds yet unknown.

Astronomers

An astronomer is a scientist who studies everything in space. This includes stars, planets, moons, galaxies, comets, black holes, and the universe itself. Astronomers use telescopes, satellites, and computers to observe the sky and understand how space objects move, change, and interact. Astronomers observe stars, planets, and galaxies. They use telescopes on Earth or in space and study how the universe began and how it works. They also discover new planets or star systems and record and analyze data about space objects.

What We Can See in Space

When we look into space—either with our eyes, telescopes, or spacecraft—we can see many incredible things, including: stars , planets, comets, galaxies , asteroids and meteoroids. Stars are the huge glowing balls of gas that fill the universe however they look very small because they are very far from the earth. Sun is our star and is the nearest of all . There are many natural satellites that orbit planets. Earth has one- moon , but some planets have dozens. Planets are the worlds of different sizes, such as Mars, Jupiter, and Saturn with its famous rings. Comets are the icy objects that glow and develop long tails when they get close to the Sun. Galaxies refers to the huge collections of billions of stars, dust, and gas. The Milky Way is our galaxy. Nebulae is another thing with clouds of gas and dust where stars are born or where they explode. Apart from these , there are many artificial satellites & Space Stations. These are the machines humans have sent into orbit, like the International Space Station. Some black holes are invisible, extremely dense regions that even light cannot escape from. Asteroids & Meteoroids are the rocky objects floating in space, sometimes entering Earth’s atmosphere as “shooting stars.”

Stars and Constellations

Stars are giant balls of hot, glowing gases—mostly hydrogen and helium. They produce their own light and heat through nuclear reactions happening deep inside them. Our Sun is a star, but it is only one of the billions of stars in the universe. Stars can be different sizes, colors, and temperatures. Some are small and dim, while others are huge and incredibly bright. Constellations are patterns of stars that people long ago imagined into shapes, such as animals, humans, or objects. These patterns help us identify and map different parts of the night sky. Some well-known constellations include: Orion – the Hunter, Ursa Major – the Great Bear (includes the Big Dipper), Cassiopeia – the Queen and Scorpius – the Scorpion. Even though stars in a constellation may look close together, they are often far apart in space. Constellations help astronomers map the sky and are used for navigation by sailors and travelers. Groups of stars sometimes form patterns that look like familiar shapes. Long ago, our ancestors enjoyed watching these stars. They noticed these patterns and linked them to animals, objects, or characters from stories.

Constellations for navigation

These groups of stars that form patterns are called constellations. The stars in a constellation are often connected by imaginary lines to make the pattern easier to see. Some constellations also help find directions. The Big Dipper has two pointer stars lead directly to the North Star while Orion appears in different seasons and helps sailors tell the time of year. Southern Cross is used in the Southern Hemisphere to find south. Stars rise in the east and set in the west, just like the Sun, so their movement helped travellers know where they were heading. Even today, star navigation is still taught as a backup skill for pilots and sailors.

Apps for Identifying Stars, Constellations, and Planets

 Sky Map – A mobile app that helps you identify stars, constellations, and planets by pointing your phone at the sky. Stellarium – Available on both mobile and computer; the computer version is free and has many useful features for sky observation

 Stars and Navigation

For thousands of years, people have used stars to find their way across land and sea. Before compasses, GPS, or maps existed, sailors and travelers looked up at the night sky to guide their journeys. Certain stars and star patterns appear in the same part of the sky every night, making them reliable markers for direction.  The North Star (Polaris) is one of the most important stars for navigation is the North Star, also called Polaris. It stays almost fixed in the sky directly above the North Pole. When you face Polaris, you are facing north. This made it extremely useful for sailors in the Northern Hemisphere.

Telescope

A telescope is an instrument that helps us see objects that are far away, especially in space. It collects light and magnifies distant objects like stars, planets, and galaxies so that they appear clearer and brighter. A telescope make distant objects look closer to help the astronomers study space. It show details that the human eye cannot see and capture images of planets, stars, and other celestial objectswer52

Types of telescopes

Optical telescopes – use lenses or mirrors to gather light. Radio telescopes – detect radio waves from space and space telescopes – placed outside Earth’s atmosphere (like the Hubble Space Telescope) for clearer views

International Astronomical Union (IAU)

The International Astronomical Union (IAU) is a global organization of professional astronomers founded in 1919 and headquartered in Paris. It is the internationally recognized authority responsible for naming celestial objects such as planets, dwarf planets, stars, asteroids, and their surface features. The IAU also sets scientific standards for astronomy, including definitions, coordinate systems, and timekeeping. With more than 13,500 members from over 100 countries, the IAU works to promote and safeguard the science of astronomy through research, international collaboration, and worldwide outreach programs.

Night Sky Watching

On clear, cloudless nights, you can see many stars in the sky. But in big cities, only a few stars are visible because of light pollution, smoke, and dust. Light pollution occurs when too much artificial light shines into the sky at night. In villages or rural areas where there is less light pollution, the night sky looks much clearer, and more stars can be seen. Tall buildings and trees around your home can also block the view of the sky. Not all stars and constellations are visible everywhere or throughout the year. For example, the Pole Star cannot be seen from the southern part of Earth. To identify a star or a constellation, you must know its shape and where it appears in the sky. Pictures of constellations are useful for recognizing their patterns. You can also use sky-mapping apps on your phone, which guide you on when and where to look for specific stars or constellations.

Steps of night-Sky Watching

Choose a dark, open area with little or no artificial light. Make sure the place is safe and an adult is present. Pick a date and time depending on which stars or constellations you want to observe. A moonless, clear night is best, especially for viewing faint stars like the Pole Star. Carry a mobile app with a sky map OR printed constellation charts, magnetic compass and a notebook for drawing or writing your observations. Go to the location at the chosen time with an adult. After reaching, wait for 30 minutes to let your eyes adjust to the darkness. This helps you see faint stars more easily.

Light Pollution

Light pollution is increasing around the world, making it difficult for people to view or study stars and other objects in the night sky. To protect dark skies, some places have been declared dark sky reserves or parks, where lighting is controlled to keep the sky naturally dark for research and stargazing. Several organizations work to create awareness about light pollution and teach ways to reduce it.

Our Solar System

The Solar System is like a large family of objects in space. At its centre is the Sun, which provides Earth with light, heat, and energy. All planets, moons, asteroids, and comets revolve around the Sun, forming this vast and dynamic system.

The Sun

The Sun is a star and the closest one to Earth. It is a huge, extremely hot ball of gases that releases enormous amounts of energy. It is the main source of heat and light, making life possible on Earth. Although the Sun is almost 100 times wider than Earth, it appears small because it is very far away from us. The Sun looks larger than other stars because it is much closer. Stars in the night sky appear as tiny points of light because they are at extremely large distances. During the day, the Sun’s brightness hides these distant stars from view. The Earth is about 150 million kilometres away from the Sun. To measure such huge distances, scientists use a unit called an astronomical unit (au), which equals the average distance between the Earth and the Sun. The Sun is not only a giant ball of hot gases but also the brightest object in our sky and the primary source of light and heat. Because of its importance, many ancient cultures, including those in India, worshipped the Sun as a god. In India, the Sun is known as Surya. The Sun’s heat keeps Earth at a comfortable temperature, making life possible. Sunlight is essential for photosynthesis, the process by which plants grow. Plants form the base of the food chain and supply both food and oxygen to all living beings. The Sun also influences climate, seasons, weather, the water cycle, and winds. These natural processes are essential for maintaining life on Earth.

The Nearest Star: Proxima Centauri

Proxima Centauri is the closest star to Earth after the Sun. It is part of the Alpha Centauri star system, which is the nearest star system to our Solar System. Proxima Centauri is located at an enormous distance—about 269,000 times farther from us than the distance between the Earth and the Sun. This distance is roughly 269,000 astronomical units (au), where 1 au is the average distance between the Earth and the Sun. Because Proxima Centauri is so far away, it appears as a faint point of light in the night sky, even though it is a real star like the Sun. Despite being the nearest star after the Sun, reaching it with current spacecraft technology would take thousands of years due to the vast distance.

Planets of Our Solar System

Our Solar System has eight planets that revolve around the Sun in fixed paths called orbits. Each planet is unique in size, temperature, composition, and appearance. The planets are divided into two groups: Inner (rocky) planets and Outer (gas/ice) planets.

1. Mercury

Mercury is the closest planet to the Sun and the smallest in the Solar System. It has no atmosphere to trap heat, so its days are extremely hot and nights are freezing cold.

2. Venus

Venus is similar in size to Earth but is covered with thick clouds of poisonous gases. It is the hottest planet because its dense atmosphere traps heat. It is also called the “Morning Star” or “Evening Star” because it shines brightly.

3. Earth

Earth is the only known planet that supports life. It has water, air, and a suitable temperature for living organisms. About 71% of Earth’s surface is covered with water, and it has one natural satellite—the Moon.

4. Mars

Mars is known as the Red Planet because of its reddish soil. It is smaller than Earth and has a very thin atmosphere. Scientists believe that Mars may have once had water and could possibly support life in the future.

5. Jupiter

Jupiter is the largest planet in the Solar System and is made mostly of gases like hydrogen and helium. It has a giant storm called the Great Red Spot. Jupiter has more than 75 moons.

6. Saturn

Saturn is famous for its beautiful rings, which are made of ice and rock particles. It is the second-largest planet and is also a gas giant like Jupiter.

7. Uranus

Uranus is an ice giant with a bluish color because of methane gas in its atmosphere. It is unique because it rotates on its side, making its seasons very unusual.

8. Neptune

Neptune is the farthest planet from the Sun. It is extremely cold and windy, with strong storms. Like Uranus, it is also an ice giant.

Natural Satellites

A natural satellite is a heavenly body that orbits a planet without any human-made technology involved. These satellites are formed by nature and not created or launched by humans. The most well-known natural satellite is the Moon, which orbits Earth. Natural satellites revolve around planets due to the force of gravity. They do not produce their own light but reflect the light of the Sun. Natural satellites vary in size — some are large like Earth’s Moon, while others are very small, like the irregularly shaped moons of Mars or Jupiter. A planet can have no moons, one moon, or many moons. For example, Earth has one, Mars has two, and Jupiter has more than 90.

Examples of Natural Satellites

Earth has moon – Earth’s only natural satellite. Mars has Phobos and Deimos – Small, irregular-shaped moons. Jupiter hasGanymede, Europa, Io, Callisto, and many more (Ganymede is the largest moon in the Solar System.) Saturn hasTitan, Enceladus, Rhea, and others. Uranus & Neptune have both have multiple moons such as Triton (Neptune) and Titania (Uranus).

The Moon

The Moon is Earth’s only natural satellite and the closest celestial body to our planet. It does not have its own light; instead, it reflects the Sun’s light, which is why it appears bright in the night sky. The Moon has been observed and studied since ancient times and plays an important role in many natural processes on Earth. The Moon is about 3,84,400 km away from Earth. It is much smaller than Earth, with a diameter about one-fourth that of our planet. The Moon has no air (atmosphere), so there is no weather, wind, or sound. bIts surface is covered with craters, mountains, and plains formed by the impact of rocks from space. The Moon appears to change its shape every night. These changing shapes are called phases of the Moon.
The major phases are: New Moon, Crescent, Half Moon (First Quarter/Last Quarter), Gibbous and Full Moon. The phases occur because the Moon revolves around Earth and we see only the lighted part at different angles. The Moon takes about 27.3 days to rotate once on its axis. It also takes 27.3 days to revolve around Earth. Because both motions take the same amount of time, the same side of the Moon always faces Earth. This is why we never see the Moon’s far side from Earth. The Moon’s gravity causes tides in Earth’s oceans. It helps maintain the Earth’s tilt and stability, which affects climate. The Moon has inspired calendars, festivals, art, and scientific studies for centuries. It is the only celestial body visited by humans — astronauts first landed on the Moon during the Apollo 11 mission in 1969.

Asteroids and Comets

Asteroids are small, rocky objects that orbit the Sun. They are much smaller than planets and do not have air, water, or life. Most asteroids are found in a region called the Asteroid Belt, which lies between Mars and Jupiter. This belt contains thousands of asteroids of different sizes—some as small as pebbles and some hundreds of kilometers wide.

Characteristics of Asteroids

• Made mostly of rock and metal
• Irregular in shape (not round like planets)
• Do not produce their own light
• Leftover pieces from the early formation of the Solar System
• Sometimes called minor planets

Examples

• Ceres – the largest asteroid (also classified as a dwarf planet)
• Vesta, Pallas, Hygiea – other large asteroids

Comets

Comets are often called “dirty snowballs” because they are made of ice, dust, and frozen gases. They orbit the Sun in very long, stretched (elliptical) paths. When a comet comes near the Sun, its ice begins to melt and forms a bright glowing head and a long tail.

Characteristics of Comets

• Made of ice + dust + frozen gases
• Develop a glowing coma (cloud of gas) and a tail when near the Sun
• The tail always points away from the Sun due to solar wind
• They shine because they reflect sunlight
• Their orbits can take hundreds or thousands of years

Examples

• Halley’s Comet – the most famous comet, visible from Earth every 76 years
• Comet Hale–Bopp – one of the brightest comets in recent history

Difference Between Asteroids and Comets

Feature	Asteroids	Comets
Composition	Rock and metal	Ice, dust, and gases
Orbit	Mostly between Mars and Jupiter	Long elliptical orbits
Appearance	No tail; rocky	Bright head + long tail when near Sun
Origin	Inner Solar System	Outer Solar System (Kuiper Belt & Oort Cloud)

Galaxy

Galaxies are enormous systems made up of millions to billions of stars, along with gas, dust, and dark matter, all held together by gravity. They come in different shapes such as spiral, elliptical, and irregular galaxies. Galaxies are the basic building blocks of the universe, and each galaxy contains its own stars, planetary systems, nebulae, and other celestial objects. They constantly move and interact with each other, sometimes even merging over billions of years.

Our galaxy, the Milky Way, is a large spiral galaxy with a central bulge and long, curved arms. It contains over 100 billion stars, including our Sun. The Sun is located in one of the spiral arms called the Orion Arm. The Milky Way is about 100,000 light-years across and slowly rotates, with all stars and objects orbiting around its center, where a supermassive black hole called Sagittarius A* exists. Our entire solar system is just a tiny part of this vast galaxy, which itself is one of billions of galaxies in the universe.

The Universe

• Beyond the Milky Way Galaxy, there are countless other galaxies in outer space. Scientists study these galaxies to learn more about stars, galaxies, and the universe as a whole.
• One of the big questions scientists are trying to answer is whether there is life anywhere else in the universe. 
• So far, the search for life has focused mainly on exoplanets, which are planets that orbit stars other than our Sun, within our galaxy. 
• Although scientists have not yet found any evidence of life on these exoplanets, the search continues.

Beyond Earth Class 6th Science Chapter 12 Question Answer

Question 1. Match the column:

Column I	Column II
(i) Satellite of Earth	Venus
(ii) Red planet	Orion
(iii) Constellation	Mars
(iv) Planet which is commonly called an evening star	Moon

Answer:

Column I	Column II
(i) Satellite of Earth	(d) Moon
(ii) Red planet	(c) Mars
(iii) Constellation	(a) Orion
(iv) Planet which is commonly called an evening star	(b) Venus

Question 2. (i) Solve the following riddle:
My first alphabet is the MAN but not in CAN.
My second alphabet is in ACE also, in FAN.
My third alphabet is the RAT and not in CAT.
My fourth alphabet is in SUN but not in FUN.
Answer: MARS

(ii) Make two similar riddles by yourself.
Answer:
(a) My first alphabet is in VAN but not in PAN
My second alphabet is in EARTH and also in HEAVEN
My third alphabet is in ONE and not in TWO
My fourth alphabet is in SUN and also in FUN
My last alphabet is in STAR but not in RADAR
I am a planet that moves around the Sun.
Answer: VENUS

(b) My first alphabet is in EAT but not in BAT
My second alphabet is in FAT and also in SAT
My third alphabet is in RAT and not in MAT
My fourth alphabet is in TEN and also in NET
My fifth alphabet is in HAT but not in PAT.
I am a planet that moves round the Sun.
Answer: EARTH

Question 3. Which of the following is not a member of our solar system?
(i) Sirius
(ii) Comets
(iii) Asteroids
(iv) Pluto
Answer: (i) Sirius

Question 4. Which of the following is not a planet of the Sun?
(i) Jupiter
(ii) Pluto
(iii) Neptune
(iv) Saturn
Answer: (ii) Pluto

Question 5. Which is the brighter star, the Pole star or sirius?
Answer: Sirius is the brightest star in the night sky.

Question 6. An artist’s representation of the solar system is given in the figure. Is the order of the planets correct? If not, write the correct order in the boxes in the figure.

Answer: The correct sequence is as follows: 1,3,2,4,5,7,6,8

Question 7.A portion of night sky with stars is shown in Fig. Look carefully and identify the groups of stars that from the pattern- the Big Dipper and the Little Dipper. Draw lines to connect the stars for these patterns and label the Pole star. You may refer to Fig .12 for help.
Answer:

Question 8.
A portion of the night sky is shown in Figure. Draw lines to connect the stars for Orion and label the star Sirius. You may refer to Fig. 12.3.

Answer:

Question 9.You can see stars fading away at dawn and appearing at dusk. During the day we do not see the stars. Explain why.
Answer: During the day, the Sun’s bright light outshines the stars, making them invisible to our eyes. The atmosphere scatters Sunlight, creating the blue sky and masking the faint light of the stars.

Question 10. During a clear night try to observe the big depart 3-4 times at an interval of 2-3 hours. Also try to locate the pole star each time. Does the Big Dipper appears to move? Draw a rough sketch. to illustrate this, mentioning the time in each case.
Answer: The Big Dipper appears to move around the Pole Star due to the rotation of the Earth. Over a few hours, its position changes, making it seem as if it is rotating around the Pole Star.

Question 11.Think about the night sky and write a poem or a story on it.
Answer: Today I saw a comet while watching the night sky. I told my grandparents about this episode and to this, they reply it is a messenger of disaster like pandemic or flood.
But these are all myths and superstition, As I learned in my institution.
Appearance of a comet is a natural phenomenon. We have no reason to be afraid of this Grandma.

ADDITIONAL QUESTIONS

Multiple Choice Questions (MCQ)

Question 1. What is the main function of stars in ancient navigation?

(a) They provide heat.
(b) They help travellers find their way.
(c) They create light pollution.
(d) They are used for decoration.

Answer (b) They help travellers find their way.

Question 2. Which constellation is known as "The Hunter"?

(a) Canis Major
(b) Orion
(c) Taurus
(d) Ursa Major

Answer

(b) Orion

Question 3. What do you call the star that remains in the same position in the night sky?

(a) Sirius
(b) Polaris
(c) Betelgeuse
(d) Vega

Answer

(b) Polaris

Question 4. How many official constellations are recognized by the International Astronomical Union (IAU)?

(a) 88
(b) 100
(c) 72
(d) 50

Answer

(a) 88

Question 5. What is the closest star to Earth after the Sun?

(a) Alpha Centauri
(b) Proxima Centauri
(c) Sirius
(d) Betelgeuse

Answer

(b) Proxima Centauri

Fill in the Blanks

1. The imaginary lines that connect stars to form patterns are called _____.
2. The _____ is the star at the center of our Solar System.
3. _____ pollution makes it difficult to see stars in big cities.
4. The _____ is known as the Red Planet.
5. The _____ takes about 27 days to orbit around the Earth.

Answer

1. Constellations
2. Sun
3. Light
4. Mars
5. Moon

True or False

1. Stars do not emit their own light.
2. The Big Dipper is part of the constellation Ursa Major.
3. The Milky Way Galaxy contains only our Solar System.
4. Asteroids are mostly found between the orbits of Earth and Mars.
5. The Sun is the closest star to Earth.

Answer

1. False 2. True 3. False 4. False 5. True

Match the Following

Column A	Column B
A) Orion	1) The Red Planet
B) Mars	2) Group of Stars
C) Polaris	3) The North Stars
D) Sun	4) Center of the Solar System
E) Comet	5) Icy body with a tail

Answer

Column A	Column B
A) Orion	2) Group of Stars
B) Mars	1) The Red Planet
C) Polaris	3) The North Stars
D) Comet	5) Icy body with a tail
E) Sun	4) Center of the Solar System

One Word Answer

Question 1. What is constellation?

Answer: The pattern formed by a group of stars in the night sky is called constellation

Question 2. Which is our star ?

Answer: The Sun is our star.

Question 3. Name the planet nearest to the ‘Sun’.

Answer: Mercury

Question 4. Name the planet nearest to the Earth.

Answer: Mars

Question 5. Name the star which is nearest to the Earth other than Sun.

Answer: Proxima Centauri

Question 6. What is the other name of Orion?

Answer: Hunter

Question 7. Which star is called Morning Star or the Evening Star?

Answer: Venus

Question 8. Name the constellation in which Big Dipper lies.

Answer: Ursa Major

Question 9. Name the planet which have two moons.

Answer: Mars

Question 10. How many constellations were officially listed by the International Astronomical Union (IAU)?

Answer: 88 constellations

Question 11. Which planet has rings around it?

Answer: Saturn

Question 12. Which star is part of the Little Dipper?

Answer: Pole Star or Polaris

Question 13. Name the planet farthest from the Sun.

Answer: Neptune

Question 14. Which constellation contains the star Sirius?

Answer: Canis Major

Question 15. How many planets are there in our Solar System?

Answer: Eight

Very Short Answer Questions

Question 1. Why is the Earth called a blue planet?

Answer: From the outer space, the earth appears blue because its three- fourths surface is covered by water. It is, therefore, called a blue planet.

Question 2. What is Universe?

Answer: The Universe is a large space consisting of celestial bodies like the stars, planets, galaxy, dust and gases.

Question 3. What is the primary purpose of constellations in modern astronomy?

Answer: In modern astronomy, constellations help in identifying and locating stars and other celestial objects.

Question 4. What is meant by the ‘Solar System’?

Answer: The sun, eight planets, satellites and some other celestial bodies known as asteroids and meteoroids form the solar system.

Question 5. What is revolution?

Answer: The motion of the earth around the sun in its orbit is known as revolution.

Question 6. What is a galaxy?

Answer: A galaxy is a large system of stars, gas, and dust bound together by gravity.

Question 7. What are asteroids?

Answer: Many small objects in the solar system are rocky and irregular in shape, known as asteroids.

Question 8. Define asteroid belt.

Answer: Many asteroids revolve around the Sun between Mars and Jupiter in a region known as the asteroid belt.

Question 9. What is the shape of the Milky Way Galaxy?

Answer: Our Milky Way Galaxy is a spiral galaxy having a whitish broadband. It looks like a spinning pinwheel
when viewed from top or bottom.

Question 10. How many planets in the solar system are made of gas? Name them.

Answer: Four planets are made out of gas and they are also referred to as gas giants. They are Jupiter, Saturn, Uranus, and Neptune.

Question 11.What are the special characteristics of the Pole Star?

Answer: Pole Star does not move as other stars move and it is part of Little Dipper.

Short Answer Questions

Question 1. Why is Venus known as the Evening Star or the Morning Star?

Answer: Venus is called the Evening Star or the Morning Star because it is often visible at dawn or dusk, shining brightly either in the western sky after sunset or in the eastern sky before sunrise.

Question 2. Explain why the Pole Star is important for navigation.

Answer: The Pole Star is important for navigation because it remains nearly stationary in the sky, indicating the direction of true north. This made it a reliable point of reference for travelers and sailors before the advent of modern navigation tools.

Question 3. Why is the Sun important to our life?

Answer: Sunlight is essential for plants to grow, which provide food and oxygen to animals, including humans. The Sun is responsible for climate, seasons, weather, water cycle, winds—all of which are important for sustaining life on the Earth.

Question 4. Why are stars invisible during the day time?

Answer: Stars are far away from us compared to the Sun. So, the glare of the Sun is much more than the glare of star during the daytime. Therefore stars are not visible during the day time.

Question 5. Write any two points about the planet Mars.

Answer: (i) Mars is the red planet due to reddish soil
(ii) Mars is the fourth planet from the Sun.

Question 6. Why is the Earth called a unique planet?

Answer: The earth is a unique solar system planet because:

1. Conditions favourable to supporting life are only to be found on earth.
2. The earth is neither too hot nor too cold.
3. There are water and air in it, which are very important for our survival.

Question 7. What is the significance of the Milky Way Galaxy in our understanding of the universe?

Answer: The Milky Way Galaxy is significant because it is our home galaxy, containing our Solar System. Studying the Milky Way helps us understand the structure, formation, and evolution of galaxies, as well as the place of our Solar System within the universe.

Question 8. How do comets differ from asteroids?

Answer: Comets are composed of ice, dust, and rocky material and often have a visible coma or tail when they come close to the Sun. Asteroids, on the other hand, are made mostly of rock and metal and do not develop tails.

Question 9. Describe the importance of the Sun in the Solar System.

Answer: The Sun is crucial in the Solar System as it is the primary source of energy, providing the heat and light necessary for life on Earth. It also governs the orbits of the planets and other objects through its gravitational pull.

Long Answer Questions

Question 1. How does a planet differ from a star?

Answer

Planet	Star
The celestial bodies which revolve around the sun in certain orbit are called planets.	Stars are the celestial bodies which can emit heat and light continuously.
Planets do not twinkle in the sky.	Stars twinkle in the sky.
They do not have their own light.	They have their own light.
They revolve around the sun.	They are fixed at a point.
Planets are small as compared to stars.	They are very big in size.

Question 2. What are constellations? Explain some common constellations.

Answer: The group of stars that has a recognisable pattern is called constellation.
Some common constellations are:

1. Canis Major:It appears like a dog. It contains a star called Sirius; the brightest star in the night sky.
2. Taurus:It looks like is a bull. It contains two types of stars; a group of stars called Pleiades (Krittika). Another star in the constellation is known as Aldebaran (Rohini).
3. Orion:This constellation contains three stars in the middle which represent the belt of the hunter. It is also called the hunter. Orion contains other star (nakshatra) known as Betelgeuse (Ardra)