Stars And The Solar System

Moon and the stars are the celestial objects which we can see easily in the night sky.

Alpha Centauri is the star which is closest to the Earth after the Sun. It is at a distance of about 40,000,000,000,000 km from the Earth.

The pole star is the star which remains fixed at the same place in the sky in the North.

Light year is the unit used to express distance between the various celestial bodies. Light year is the distance travelled by light in one year. The speed of light is 300,000 km per second. For example, the Sun is nearly 150,000,000 Km i.e. 150 million Km away from the Earth. The distance of the Sun from the Earth may be said to be about 8 light minutes.

The distance between the Earth and stars and the distance between the stars is very large. The stars are millions of times farther away than the Sun. the Sun is nearly 150,000,000 Km i.e. 150 million Km away from the Earth. It is inconvenient to express these distances in kilometres. Therefore, these large distances are expressed in light years. For example, the distance of the Sun from the Earth may be said to be about 8 light minutes.

The distance between the Earth and stars and the distance between the stars is very large. It is inconvenient to express these distances in kilometres. Therefore, these large distances are expressed in light years.

1 light year= 9.46 × 10¹² Km. Now, a star is 8 light years away from the Earth. It means the distance between the star and the Earth is equal to the distance travelled by light in eight years.

Therefore, the star is located 8 × 9.46 × 10¹² Km = 75.68 × 10¹² Km away from the Earth.

Ursa Major is the constellation which reminds us of a large ladle or a question mark in the night sky. It is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark. There are three stars in the handle of the ladle and four in its bowl.

The constellation Orion is visible during winter in the late evenings. It also has seven or eight bright stars. It is also called the Hunter. The three middle stars represent the belt of the hunter. The four bright stars appear to be arranged in the form of a quadrilateral.

Ursa Major can be seen during summer time in the early part of the night. It has seven prominent stars.

Ursa Major constellation is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark.

(a) Cassiopeia is another prominent constellation in the northern sky. It is visible during winter in the early part of the night. It looks like a distorted letter W or M.

(b) Leo Major is visible in the northern hemisphere around the spring. It is easily identifiable through may. Its brightest star is Regulus. Its most prominent pattern of stars is a backwards question mark called the Sickle. You can use the Pointer stars of the Big Dipper to find Leo Major.

Jupiter is the biggest planet of the Solar system. It is so large that about 1300 earths can be placed inside this giant planet.

Mercury is the smallest planet of the Solar system. It is nearest to the Sun.

The Sun and the celestial bodies which revolve around it form the solar system. It consists of large number of bodies such as planets, comets, asteroids and meteors. The Gravitational force keeps the members of the Solar System bound to the Sun.

The Sun is the nearest star which is continuously emitting huge amount of heat and light. Hence, the Sun appears to be bigger and brighter than all the planets. The Sun is the source of almost all the energy on the Earth.

The Sun is the nearest star which is continuously emitting huge amount of heat and light. The Sun is the source of almost all the energy on the Earth.

The Sun is the star having a system of planets with one planet called Earth with life on it. The Earth is the only planet on the solar system on which the life is known to exist.

Saturn is the planet having a well-developed system of rings around it. These rings are not visible with the naked eye. They can be observed with a small telescope.

Mercury and Venus are the planets which lie between the Sun and the Earth. Mercury is the smallest planet and is very close to the Sun. Venus is the nearest planet to the Earth and is the brightest planet of the Solar System.

When seen from a space-ship or Moon, the Earth appears blue-green in colour. It is due to the reflection of light from the water and landmass on its surface.

(a) Mercury is the planet nearest to the Sun. It is the smallest planet of our Solar System.

(b) Neptune is the farthest planet from the Sun. It is the fourth largest planet in the Solar System.

Uranus and Neptune have been discovered with the help of telescope. These are the outermost planets of the solar system. They can be seen only with the help of large telescopes

Mercury and Venus shows phases like the Moon. They have the orbits which are smaller than the Earth and exhibit the full range of phases like the moon.

Earth is the only planet of the Solar System having life on it. The special environment conditions are responsible for the existence and the continuation of life on the Earth. These conditions include the right distance from the Sun, so it has the right temperature, the presence of water, suitable atmosphere and a blanket of ozone.

Mars appears slightly reddish in colour and is also called the red planet. It has two small natural satellites.

Mars is known as the red planet. It appears slightly reddish in colour due to the presence of iron oxide on its surface.

Venus appears in the eastern sky before sunrise. It is known as morning star. Sometimes, it appears in the western sky just after sunset. It is known as Evening star.

Saturn has rings around it which makes it unique in the Solar System. These rings can be observed with a small telescope and cannot be seen with the naked eye. Saturn also has a large number of satellites.

Mercury and Venus can be seen as ‘Morning Star’ and ‘Evening Star’.

The celestial body which revolves around a planet is known as a Satellite. Moon is a natural satellite of the Earth.

Mars and Jupiter have asteroids between them. These planets have a large gap between the orbits. This gap is occupied by a large number of small objects that revolve around the Sun called the asteroids.

Asteroids and Comets are the two objects other than planets which are members of the Solar System.

Comets are the member of the Solar System which appears in the sky like a bright ball of light with a long glowing tail. The length of the tail grows in size as it approaches the sun.

Meteor is seen as a bright streak of light coming down the night sky. A meteor is usually a small object that occasionally enters the Earth’s atmosphere.

Asteroids are the celestial objects which are also called minor planets. Asteroids can only be seen through large telescopes.

Moon is the natural satellite of the Earth. Aryabhatta was the first Indian artificial satellite of the Earth.

ISRO also known as Indian Space Research Organisation is the agency responsible for the development of space science programs in India.

Aryabhatta was the first artificial satellite launched by India.

Artificial satellites are used for forecasting weather, transmitting television and radio signals. They are also used for telecommunication and remote sensing.

INSAT stands for the Indian National Satellite System. It is a series of multipurpose geo-stationary satellites launched by ISRO to satisfy the telecommunications, broadcasting, meteorology, and search and rescue operations.

IRS stands for Indian Remote Sensing satellite program.

(a) Ursa Major can be seen during summer time in the early part of the night. It has seven prominent stars.

(b) Cassiopeia is another prominent constellation in the northern sky. It is visible during winter in the early part of the night. It looks like a distorted letter W or M.

(a) This statement is False.

Orion is clearly visible in the night sky from November to February.

(b) This statement is False.

Pole star is a name of Polaris in the constellation Ursa Minor, after its property of being the naked-eye star closest to the Earth's celestial north pole.

(c) This statement is True.

Mercury is the planet nearest to the Sun. It is the smallest planet of our Solar System.

(d) This statement is False.

Neptune is the farthest planet in the Solar System.

(e) This statement is False.

There are eight planets in the Solar System. In 2006, the International Astronomical Union (IAU) adopted a new definition of a planet. Pluto does not fit this definition. It is no longer a planet of the solar system.

(f) This statement is True.

Comets are the members of the Solar System. They revolve around the Sun in highly elliptical orbits.

(g) This statement is True.

Artificial satellites are man-made. They are launched from the Earth.

(a) The correct answer is ………... twinkle.

Stars twinkle because we are able to see them through the thick layers of turbulent atmosphere.

(b) The correct answer is ……. star and …...constellation.

The constellation Orion is visible during winter in the late evenings. It also has seven or eight bright stars.

(c) The correct answer is …… constellation.

The stars forming a group that has a recognisable shape is called a constellation. We can easily identify them in the night sky.

(d) The correct answer is ……. Sirius.

Sirius is a star system and the brightest star in the Earth's night sky.

(e) The correct answer is …… Pole.

Ursa Major can be seen during summer time in the early part of the night. It has seven prominent stars.

(f) The correct answer is ……. Sirius and ……Pole.

Orion is clearly visible in the night sky from November to February. The pole star is the star which remains fixed at the same place in the sky in the North.

(g) The correct answer is ……. Neptune.

Neptune is the farthest planet from the Sun. It is the fourth largest planet in the Solar System.

(h) The correct answer is ……… Mars.

Mars appears slightly reddish in colour and is also called the red planet. It has two small natural satellites.

(i) The correct answer is …... asteroids.

Asteroids are the celestial objects which are also called minor planets. Asteroids can only be seen through large telescopes.

(j) The correct answer is …... Mars and …... Jupiter.

Asteroids are the celestial objects which are also called minor planets. Asteroids can only be seen through large telescopes.

(k) The correct answer is ……. Stars.

Meteors are commonly known as shooting stars, although they are not stars. A meteor is usually a small object that occasionally enters the earth’s atmosphere.

(l) The correct answer is …… satellite.

A body revolving around another body is called a satellite. Moon is the natural satellite of the Earth. Some planets also have natural satellites.

(m) The correct answer is …. meteor.

Meteors are commonly known as shooting stars, although they are not stars. A meteor is usually a small object that occasionally enters the earth’s atmosphere.

(n) The correct answer is …... artificial.

Artificial satellites are man-made. They are launched from the Earth.

The stars, the planets, the moon and many other objects in the sky are called celestial objects. The moon is the brightest object in the night sky. Stars are celestial bodies that emit light of their own. Our sun is also a star. Moon is the natural satellite of the Earth. The Sun and the celestial bodies which revolve around it form the solar system. These celestial bodies include the planets, comets, asteroids and meteors.

Stars are 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. Stars appear 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. Some groups of stars appear to form recognizable groups known as constellation. The Sun is the star nearest to the Earth. It is the source of almost all energy on the Earth. The Sun is the main source of heat and light for all the planets.

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. The Pole Star is not visible from the southern hemisphere. Some of the northern constellations like Ursa Major may also not be visible from some points in the southern hemisphere.

The stars appear to move in the sky. It appears because of the motion of the Earth. Earth is spinning around its own axis and also moves around the Sun. As a result, the stars also appear to move from east to west. A star which rises in the east in the evening, sets in the west in the early morning. All the stars do not appear to move. For example, pole star does not appear to move because it is situated in the direction of earth’s axis.

The stars forming a group that has a recognisable shape is called a constellation. We can easily identify them in the night sky. Ursa Major and Orion are the examples of the constellations. Ursa Major is the constellation which reminds us of a large ladle or a question mark in the night sky. It is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark. The constellation Orion is visible during winter in the late evenings. It also has seven or eight bright stars. It is also called the Hunter. The three middle stars represent the belt of the hunter. The four bright stars appear to be arranged in the form of a quadrilateral.

Sunlight travels at the speed of light. Light emitted from the surface of the Sun has to travel across the vacuum of space to reach our eyes. It takes an average of 8 minutes and 20 seconds for the sunlight to travel from the Sun to the Earth.

The next nearest star to Earth is 'Proxima Centauri'. It is 4.24 light years from the Sun. Its light will take 4.24 years to reach us.

The Sun and the celestial bodies which revolve around it form the Solar System. It consists of large number of bodies such as planets, comets, asteroids and meteors. The Gravitational force keeps the members of the Solar System bound to the Sun. The Sun is the star having a system of planets with one planet called Earth with life on it. Comets are the member of the Solar System which appears in the sky like a bright ball of light with a long glowing tail. Asteroids are the celestial objects which are also called minor planets. Asteroids can only be seen through large telescopes. Meteors are commonly known as shooting stars, although they are not stars. A meteor is usually a small object that occasionally enters the earth’s atmosphere.

Planets are the members of the Solar System. They look like stars but they do not have light of their own. They reflect the sunlight that fall on them. They keep changing their positions with respect to the stars. A planet revolves around the Sun in a definite path. This path is called an orbit. The time taken by a planet to complete one revolution is called its period of revolution. As the distance of the planet increases from the Sun, the period of revolution increases. A planet also rotates on its axis besides revolving around the Sun. The time taken by the planet to complete one rotation is called its period of rotation. Some planets have moons or satellites revolving around them.

The Sun and the celestial bodies which revolve around it form the Solar System. The Gravitational force keeps the members of the Solar System bound to the Sun. The Earth is a planet. It is the member of the Solar system. The eight planets in their order of their increasing distance from the Sun are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

There are eight planets in the Solar System. The first four planets, Mercury, Venus, Earth and Mars are much nearer the Sun than the other four planets. They are called the inner planets. The inner planets have very few moons. The planets outside the orbit of Mars, namely Jupiter, Saturn, Uranus and Neptune are much farther off than the inner planets. They are called the outer planets. They have a ring system around them. The outer planets have large number of moons. The outer planets can be seen only with the help of large telescopes.

Mercury is the nearest planet to the Sun. It is the smallest planet of our Solar System. It is very close to the Sun which makes it very difficult to observe. This is because most of the time it hidden in the glare of the Sun. However, it can be observed just before sunrise or just after sunset, near the horizon. Mercury has no satellite of its own.

Planets are the members of the Solar System. They look like stars but they do not have light of their own. They reflect the sunlight that fall on them. Whereas the stars emit light of their own. The Sun is also a star.

Earth is the only planet of the Solar System having life on it. The special environment conditions are responsible for the existence and the continuation of life on the Earth. These conditions include the right distance from the Sun, so it has the right temperature, the presence of water, suitable atmosphere and a blanket of ozone.

(a) The Earth rotates on its axis taking approximately 24 hours to complete one rotation. Rotation of Earth causes the day night cycle which also creates a corresponding cycle of temperature and humidity.

(b) The plane in which the Earth revolves round the Sun is called the orbital plane of the Earth. The axis of rotation of the Earth is not perpendicular to the plane of its orbit. These two planes are inclined to each other at an angle of 23.5° This tilt is responsible for the change of seasons on the Earth.

Any celestial body revolving around another celestial body is called its satellite. The Earth is the satellite of the Sun because it revolves around the Sun. The bodies revolving around the planets are considered as satellites of the planet. Moon is the natural satellite of Earth.

Moon is the natural satellite of Earth. It revolves around the Earth. The moon completes one rotation on its axis as it completes one revolution around the Earth. The moon does not produce its own light. We are able to see the moon because the sunlight falling on it gets reflected towards us. Therefore, we are able to see only that part of moon, from which the light of the Sun is reflected towards us.

(a) Ursa Major constellation is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark.

(b) Cassiopeia is another prominent constellation in the northern sky. It is visible during winter in the early part of the night. It looks like a distorted letter W or M.

(c) The constellation Orion is has seven or eight bright stars. It is also called the Hunter. The three middle stars represent the belt of the hunter. The four bright stars appear to be arranged in the form of a quadrilateral.

(d) Leo Major appears to have the shape of a big lion. It is visible in the northern hemisphere around the spring. It is easily identifiable through may. Its brightest star is Regulus. Its most prominent pattern of stars is a backwards question mark called the Sickle.

There is a large gap in between the orbits of Mars and Jupiter. This gap is occupied by a large number of small objects that revolve around the Sun. These are called asteroids. Asteroids are the celestial objects which are also called minor planets. Asteroids can only be seen through large telescopes.

Natural satellites are formed by nature. Moon is the natural satellite of the Earth. Following are the differences between the Moon and the artificial satellites of the Earth:

Artificial satellites are manmade and are launched from the Earth. They revolve around the Earth much closer than earth’s natural satellite, the moon. They have many practical applications. They are used for forecasting weather, transmitting television and radio signals. They are also used for telecommunication and remote sensing. INSAT, IRS, Kalpana-1, EDUSAT are artificial satellites.

Artificial satellites are manmade and are launched from the Earth. They revolve around the Earth much closer than earth’s natural satellite, the moon. They have many practical applications. Following are the uses of artificial satellites:

● They are used for forecasting weather.

● They are used for transmitting television and radio signals.

● They are also used for telecommunication and remote sensing.

● They help in scientific research.

● They are used in Global positioning system (GPS).

Light year is the unit used to express distance between the various celestial bodies. Light year is the distance travelled by light in one year. The speed of light is 300,000 km per second. For example, the Sun is nearly 150,000,000 Km i.e. 150 million Km away from the Earth. The distance of the Sun from the Earth may be said to be about 8 light minutes. 1 light year= 9.46 × 10¹² Km.

Comets are the member of the Solar System which appears in the sky like a bright ball of light with a long glowing tail. The length of the tail grows in size as it approaches the sun. The tail of a comet is always directed away from the sun. They revolve around the Sun in highly elliptical orbits. The period of revolution of comets around the Sun is usually very long. Many comets are known to appear periodically. Halley’s comet appears after nearly every 76 years. It was last seen in 1986.

Comets are the member of the Solar System. They revolve around the Sun in highly elliptical orbits. The period of revolution of comets around the Sun is usually very long. Comets appear periodically. Comets are visible to us in the sky like a bright ball of light with a long glowing tail. The length of the tail grows in size as it approaches the sun. The tail of a comet is always directed away from the sun.

Comets are the member of the Solar System. They revolve around the Sun in highly elliptical orbits. Comets appear periodically. Comets are visible to us in the sky like a bright ball of light with a long glowing tail. The length of the tail grows in size as it approaches the sun. The tail of a comet is always directed away from the sun.

Meteor is seen as a bright streak of light coming down the night sky. A meteor is usually a small object that occasionally enters the Earth’s atmosphere with very high speed. The friction due to the atmosphere heats it up and it glows and evaporates quickly. As a result, the bright streak lasts for a very short time. These are commonly known as shooting stars.

Stars are celestial bodies that emit light of their own. Our sun is also a star. The stars appear to move from east to west. A star which rises in the east in the evening, sets in the west in the early morning. Meteors are commonly known as shooting stars. Meteor is seen as a bright streak of light coming down the night sky. It is usually a small object that occasionally enters the Earth’s atmosphere with very high speed.

Meteorites are the large meteors which can reach the Earth before they evaporate completely. Meteorites help scientists in investigating the nature of the material from which the solar system was formed.

Meteor is seen as a bright streak of light coming down the night sky. A meteor is usually a small object that occasionally enters the Earth’s atmosphere with very high speed. The friction due to the atmosphere heats it up and it glows and evaporates quickly. As a result, the bright streak lasts for a very short time. These are commonly known as shooting stars. Meteorites are the large meteors which can reach the Earth before they evaporate completely. Meteorites help scientists in investigating the nature of the material from which the solar system was formed.

A meteoroid is a small chunk of rock or iron that travels through space. When it enters the Earth’s atmosphere, it makes a bright trail and is called a meteor. Meteor is seen as a bright streak of light coming down the night sky. A meteor is usually a small object that occasionally enters the Earth’s atmosphere with very high speed. The friction due to the atmosphere heats it up and it glows and evaporates quickly. As a result, the bright streak lasts for a very short time. These are commonly known as shooting stars. Meteors are the part of the Solar System.

Ursa Major is the constellation which reminds us of a large ladle or a question mark in the night sky. It is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark.

Following is the diagram of Ursa Major constellation:

The constellation Orion is visible during winter in the late evenings. It also has seven or eight bright stars. It is also called the Hunter. The three middle stars represent the belt of the hunter. The four bright stars appear to be arranged in the form of a quadrilateral.

Following is the diagram of Orion and Ursa Major:

Cassiopeia is another prominent constellation in the northern sky. It is visible during winter in the early part of the night. It looks like a distorted letter W or M.

Leo Major appears to have the shape of a big lion. It is visible in the northern hemisphere around the spring. It is easily identifiable through may. Its brightest star is Regulus. Its most prominent pattern of stars is a backwards question mark called the Sickle

Ursa Major has seven prominent stars. Pole star can be located with the help of Ursa Major. It is located by drawing an imaginary line passing through the two stars at the end of Ursa Major. This imaginary line is extended towards the North direction, which is about five times the distance between the two lines. This line will lead to a star which is not too bright. This star is Pole star.

Sirius is the brightest star in the sky. It is located close to the Orion constellation. An imaginary line is drawn passing through the three middle stars of Orion. By looking along this line towards the east, will lead to a very bright star. This bright star is Sirius.

There is a change in the shape of moon every day. There are days when the shape of moon appears perfectly round. Also, there are days when the moon cannot be seen at all even if the sky is clear. The day on which the whole disc of the moon is visible is called the full Moon day. Every night, the size of the bright part of the moon appears to become thinner and thinner. On the fifteenth day, the moon is not visible. This day is called the new Moon day. The next day, only a small portion of the moon appears in the sky. This is known as the crescent moon. Then again, the moon grows larger every day. On the fifteenth day once again we get a full view of the moon. After fifteen days, the full moon changes into a new Moon.

The different shapes of the bright part of the moon as seen during a month are called the phases of the moon. Moon is the natural satellite of the Earth. It revolves around the Earth. It completes one rotation on its axis as it completes one revolution around the Earth. The moon does not have light of its own. We are able to see the moon because the sunlight falling on its surface gets reflected towards us. We, therefore, see only that part of the moon, from which the light of the Sun is reflected towards us. The size of the illuminated part of the moon visible from the Earth increases each day after the new moon day. After the full moon day, the sunlit part of the moon visible from the Earth decreases in size every day. This process leads to the phases of the Moon.

Sirius is the brightest star in the sky. It is located close to the Orion constellation.

Ursa Major is the constellation which reminds us of a large ladle or a question mark in the night sky. It is also known as the Big Dipper, the Great Bear or the Saptarshi.

The stars forming a group that has a recognisable shape is called a constellation. For example, Ursa Major is a constellation.

Moon is the natural satellite of the Earth. It revolves around the Earth.

The size of the illuminated part of the moon visible from the Earth increases each day after the new moon day. After the full moon day, the sunlit part of the moon visible from the Earth decreases in size every day. This process leads to the phases of the Moon.

The stars forming a group that has a recognisable shape is called a constellation. For example, Ursa Major is a constellation.

The next nearest star to Earth is 'Proxima Centauri'. It is 4.24 light years from the Sun. Its light will take 4.24 years to reach us.

Light year is the unit used to express distance between the various celestial bodies. Light year is the distance travelled by light in one year.

The constellation Orion is visible during winter in the late evenings. It also has seven or eight bright stars. It is also called the Hunter. Cassiopeia is another prominent constellation in the northern sky. It is visible during winter in the early part of the night.

Sirius is the brightest star in the sky. It is located close to the Orion constellation.

There is a large gap in between the orbits of Mars and Jupiter. This gap is occupied by a large number of small objects that revolve around the Sun. These are called asteroids.

Jupiter is the biggest planet of the Solar system. It is so large that about 1300 earths can be placed inside this giant planet.

Saturn is the planet having a well-developed system of rings around it. These rings are not visible with the naked eye. They can be observed with a small telescope.

Ursa Major is the constellation which reminds us of a large ladle or a question mark in the night sky.

Mercury is the smallest planet of the Solar system. It is nearest to the Sun.

The moon does not have light of its own. We are able to see the moon because the sunlight falling on its surface gets reflected towards us.

Mercury and Venus shows phases like the Moon. They have the orbits which are smaller than the Earth and exhibit the full range of phases like the moon.

Venus is the hottest planet of the solar system. It is the second planet from the Sun and has a temperature that is maintained at 462 degrees Celsius.

Ursa Major can be seen during summer time in the early part of the night. It has seven prominent stars. Leo Major is visible in the northern hemisphere around the spring. It is easily identifiable through may.

ISRO is also known as Indian Space Research Organisation is the agency responsible for the development of space science programs in India.

The Indian Space Research Organisation is the space agency of the Government of India headquartered in the city of Bengaluru

(a) The general name for the group of stars like X is a constellation. The stars forming a group that has a recognisable shape is called a constellation. We can easily identify them in the night sky. Ursa Major and Orion are the examples of the constellations.

(b) X is the Ursa Major constellation. It is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark. There are three stars in the handle of the ladle and four in its bowl.

(c) Constellations is a group of stars forming a group that has a recognizable shape. Yes, Ursa Major is a part of our Solar System.

(d) There are seven prominent stars in the Ursa Major constellation. It appears like a big ladle or a question mark. There are three stars in the handle of the ladle and four in its bowl.

(e) Pole star can be located with the help of Ursa Major. It is located by drawing an imaginary line passing through the two stars at the end of Ursa Major. This imaginary line is extended towards the North direction, which is about five times the distance between the two lines. This line will lead to a star which is not too bright. This star is Pole star.

The stars appears to move from east to the west direction in the sky.

The stars appear to move in the sky. It appears because of the motion of the Earth. Earth is spinning around its own axis and also moves around the Sun. As a result, the stars also appear to move from east to west. A star which rises in the east in the evening, sets in the west in the early morning. All the stars do not appear to move. For example, pole star does not appear to move because it is situated in the direction of earth’s axis.

The constellation A is Cassiopeia. It is the prominent constellation in the northern sky. It is visible during winter in the early part of the night. It looks like a distorted letter W or M.

The constellation B is Ursa Major. It is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark. There are three stars in the handle of the ladle and four in its bowl.

The constellation C is Orion. The constellation Orion is visible during winter in the late evenings. It also has seven or eight bright stars. It is also called the Hunter. The three middle stars represent the belt of the hunter. The four bright stars appear to be arranged in the form of a quadrilateral.

The constellation D is Leo Major. Leo Major appears to have the shape of a big lion. It is visible in the northern hemisphere around the spring. It is easily identifiable through may. Its brightest star is Regulus.

(a) The constellation Orion is visible during winter in the late evenings. It also has seven or eight bright stars. It is also called the Hunter. Sirius is the brightest star in the sky. It is located close to the Orion constellation. An imaginary line is drawn passing through the three middle stars of Orion. By looking along this line towards the east, will lead to a very bright star. This bright star is Sirius.

(b) The constellation Ursa Major is also known as the Big Dipper, the Great Bear or the Saptarshi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark. Pole star can be located with the help of Ursa Major. It is located by drawing an imaginary line passing through the two stars at the end of Ursa Major. This imaginary line is extended towards the North direction, which is about five times the distance between the two lines. This line will lead to a star which is not too bright. This star is Pole star.

(i) Inner planets - (e) Earth and (g) Mars

There are eight planets in the Solar System. The first four planets, Mercury, Venus, Earth and Mars are much nearer the Sun than the other four planets. They are called the inner planets. The inner planets have very few moons.

(ii) Outer planets - (a) Saturn

The planets outside the orbit of Mars, namely Jupiter, Saturn, Uranus and Neptune are much farther off than the inner planets. They are called the outer planets. They have a ring system around them. The outer planets have large number of moons. The outer planets can be seen only with the help of large telescopes.

(iii) Constellation - (c)Great Bear and (f) Orion

The stars forming a group that has a recognisable shape is called a constellation. We can easily identify them in the night sky. Ursa Major and Orion are the examples of the constellations.

(iv) Satellite of the Earth - (d) Moon

Moon is the natural satellite of the Earth. It revolves around the Earth.