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Celestial bodies: Objects present ¡n sky or outer space.

D. Proxima Centauri 

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 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.

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.

D. Constellations 

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

Far away the sky seems to be touching the ground. The line at which they meet is called horizon.

1. Stars rise and set 4 minutes earlier every day. If star rises at 8 pm tonight, it will rise at 7:56 pm tomorrow.

2. It will rise at 5:24 pm after a month.

3. The sun and the moon are seen to move from the west to the east against the background of stars.

4. The sun moves through one degree every day and the moon through 12 to 13 degrees.

5. This happens due to the motion of the earth around the sun and the moon around the earth which affects the duration of the stars and shortens its time period.

A nakshatra is known from the brightest star that it contains. The brightest star is called the yogatara.

The moon completes one revolution around the earth in approximately 27 days. The portion celestial sphere traversed by the moon in one day is called a nakshatra.

The different constituents of our solar system are as follows :

1. Sun as a star. 

2. Eight planets, namely, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune; of which Mercury, Venus, Earth and Mars are made up of rocks and minerals, while Jupiter, Saturn, Uranus and Neptune are made up of gases.

3. Natural satellites of some planets revolving around the respective planets. 

4. Asteroids located between Mars and Jupiter. 

5. Comets made up of ice, dust and gases.

6. Meteors and meteoroids.

(i) Light takes about 8 minutes to reach us from the Sun while it takes about 1 second to reach us from the moon.

(ii) The larger the mass of a star, the faster is its evolution.

(iii) The number of fuels used in the life of a star depends on its mass.

(i) Our galaxy is called the Milky Way and Mandakini.

(ii) For measuring large distances, the light year is used as a unit.

(iii) The speed of light is 300000 km/s.

A system of billions of stars, their planetary systems and interstellar clouds of gas and dust held together by gravitational attraction is called a galaxy.

(i) Milky way is a spiral galaxy.

(ii) Stars are gigantic spheres of hot gas.

(iii) The masses of other stars are measured relative to the mass of the Sun.

(i) There are about 100 billion stars in our galaxy.

(ii) The end stage of the Sun will be a white dwarf.

(iii) Stars are born out of interstellar clouds

The ecliptic has been imagined to divided into 12 equal parts. Each part subtends 30 degrees at the centre of the celestial sphere. Each of these part is called a raashi or zodiac sign.

A group of stars occupying a small portion of the celestial sphere is called a constellation.

No. Sun is not the only star present in the Milky Way. There are lakhs of stars in the Milky Way, some of them being many times bigger than our sun. Some of them have their own planetary systems with a great diversity in colour, brightness, as well as size.

27 nakshatras. Each nakshatra is divided in padas or charan. Every nakshatra has 4 padas. These 27 nakshatra complete the entire circle of 360° of zodiac.

The zodiac comprises of 360°.

27 nakshtras: Ashwini, Bharani, Krittika, Rohini, Mrigashirasha, Ardra, Punarvasu, Pushya, Ashlesha, Magha, PurvaPhalguni, Uttara Phalguni, Hasta, Chitra, Swati, Vishakha, Anuradha, Jyeshtha, Mula, Purva Ashadha, Uttara Ashadha, Abhijit, Shravana, Dhanishtha, Shatabhishta, Purva Bhadrapada, Uttara Bhadrapada, Revati

1. Science has proved that the constituents of the solar system e.g. planets, satellites and comets as also distant stars and constellations do not have any influence on human life.

2. Man has stepped on the moon and will conquer Mars in the 21^st century.

3. Hence, in this age of science, holding on to beliefs which have been proved wrong by numerous scientific tests, is an unnecessary waste of time and energy.

4. It is important to consider all these issues with a scientific frame of mind.

Our country launched Chandrayan -1 (Satellite to moon) on 22nd October 2008 to know about the moon. 

The objectives of Chandrayan -1 are:

1. To check the possibility of finding water on the moon. 

2. Finding out the elements of matter on moon. 

3. To search for Helium – 3. 

4. To make 3 – dimensional atlas of the moon.

5. To study about the evolution of the solar system.

Now India is one of the six countries which have sent satellites to the moon.

The changes in appearance of moon are called phases of the moon.

Yes, the stars are moving.

The black spots on moon are creators of different size which on seeing from earth appear as black spots during full moon day.

1. The sun is the nearest star to us. 

2. It is continuously emitting huge amounts of heat and light and other electromagnetic radiations. 

3. The sun is the source of almost all energy on the earth.

4. In fact, the sun is the main source of heat and light for all planets of our solar system.

1. The big steady bodies shining more brightly than stars in the clear sky are called planets. 

2. They are not self luminous like stars. They appear brightly because they just act like mirrors and reflecting the sun light and heat falling on them.

1. When meteor enters the atmosphere of the earth at high speeds, these are heated up. 

2. The heat produced is so high and the meteors start glowing and eventually evaporated within a short period of time. 

3. The growing meteor bursts leaving behind a streaks of light. Therefore they are called shooting stars.

1. At night, when the sky is clear and the moon is not visible we may sometimes see bright streaks of the light in the sky. 

2. These are commonly known as shooting stars. 

3. They are not stars, they are meteors. 

4. A meteor is a small object that occasionally enters the earth’s atmosphere. 

5. It has a very high speed. 

6. The friction due to atmosphere heats it up. 

7. It glows and evaporates quickly.

8. That is why the bright streak lasts for a very short time. 

9. Some meteors are large and so they can reach the earth before they evaporate completely.

Meteors: Meteors are usually small objects that occasionally enter the earth's atmosphere.

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.

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) 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.

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

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.

Galaxy: A group of stars that contain millions of stars is called galaxies.

A group of stars which contains millions of stars are called galaxy. Our sun belongs to Milky way galaxy.

Millions of galaxies together makes our universe.

Correct option is C) Earth

Solar system: The sun and the celestial bodies which revolve around it form the solar system.

Correct option is A) Dakshinayanam
 

From December 21 to till June 21 the sun appears to shift northward. From June 21 to December 21 the sun appears to shift southward. (Basing on this information we have to give the answer suppose you have read the lesson in the month of February the sun is moving towards north direction).

Planets: The planets look like stars but they do riot have the light of their own.

Correct option is C) Meteorite

The earth’s tilt is constant 23.5 degree perpendicular. The earth position relative to sun changes, not the tilt itself during orbit. The sun is moving towards north throughout summer because the north pole is tilted 23.5 degree towards sun and we are in northern hemisphere. During the winter the south pole is tilted 23.5 degree so the sun appear to travel towards south

(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.

Correct option is D) Both A & B

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.

Every planet has two types of motion. 

1. Revolution motion: Moving around the sun. 

2. Rotation motion: Moving around an axis passing through it.