CG Board Class 8 Science Chapter 1 Solutions: Sky Vision (आकाश दर्शन) – 2026-27

Some stars which are bigger than the Sun, appear smaller to us. Why?

When objects are situated very far away from us, they appear smaller in size. Although many stars in the universe are much bigger than the Sun, the Sun is the nearest star to the Earth (about 15 crore km or 8.3 light minutes away). Other stars are situated millions of times farther away, at distances measured in light years. Due to this enormous distance, stars that are larger than the Sun appear very small to us.

One star is 3.4 light years away from the Earth. What does this mean?

A light year is a unit of distance defined as the distance travelled by light in one year at a speed of 300,000 km/s (9.46 × 10¹² km). Saying a star is 3.4 light years away means that:

1. Light emitted by that star takes 3.4 years to reach the Earth.
2. The physical distance of the star from Earth is 3.4 × 9.46 × 10¹² km = 3.2164 × 10¹³ km (32,164,000,000,000 km).

How would you find the star, which appears to be in the north?

The star that appears stationary in the north is the Pole Star (Dhruvtara). It can be found using the Ursa Major (Saptarishi) constellation:

1. Locate the saucepan-like constellation of seven stars known as Ursa Major (Saptarishi) in the night sky.
2. Identify the four stars forming the pan of the saucepan.
3. Look at the two stars at the top of the pan, known as the Indicating Stars.
4. Draw an imaginary straight line joining these two Indicating Stars and extend it towards the north direction; this line points directly to the Pole Star.

Recognize the planet according to the information given:

a) The biggest planet.

b) The planet which has life.

c) The brightest planet.

d) The red planet.

e) The first planet discovered with the telescope.

f) The planet with three rings.

g) The planet with eight satellites.

a) Jupiter (Its volume is more than the total volume of all other planets combined).

b) Earth (The only planet known to sustain life).

c) Venus (Reflects 3/4 of received sunlight due to thick clouds).

d) Mars (Appears red in color).

e) Uranus (First planet discovered with the help of a telescope).

f) Saturn (Characterized by three beautiful rings around it).

g) Neptune (Eighth planet from the Sun, having 8 satellites).

Give short notes on:

a. Those heavenly bodies that could not take the shape of a planet.

b. Those heavenly bodies which have a long shining tail.

Give the difference between meteors and meteorites.

Group of stars forming a particular shape is called _______________.

constellation / तारामंडल (Constellation)

The heavenly body which revolve round any planet is called _______.

satellite / उपग्रह (Satellite)

___________ is the coldest planet.

Neptune / वरुण (Neptune)

The ___________ star seems to be fixed at the north direction.

Pole / ध्रुव (Pole)

The shape of the _______________ constellation is like a hunter.

Orion / ओरियन / कालपुरुष (Orion)

The planet closest to the Sun is:

(a) Venus

(b) Mercury

(c) Jupiter

(d) Earth

(b) Mercury / बुध

Explanation: Mercury is the innermost planet situated closest to the Sun.

Asteroids are found in between these planets:

(a) Mars and Jupiter

(b) Saturn and Jupiter

(c) Venus and Jupiter

(d) Earth and Mars

(a) Mars and Jupiter / मंगल और बृहस्पति

Explanation: The asteroid belt revolves around the Sun in the gap between the orbits of Mars and Jupiter.

This planet does not have any natural satellite:

(a) Mars

(b) Uranus

(c) Mercury

(d) Neptune

(c) Mercury / बुध

Explanation: Mercury (as well as Venus) does not have any known natural satellite.

This is not a member of the solar system:

(a) asteroids

(b) planets

(c) satellites

(d) constellations

(d) constellations / तारामंडल

Explanation: The Solar System consists of the Sun, eight planets, their satellites, asteroids, comets, meteors, and meteorites. Constellations are distant groups of stars located outside our solar system.

This is not a constellation:

(a) Ursa Major

(b) Ursa Minor

(c) Orion

(d) Hailey

(d) Hailey / हैली

Explanation: Hailey is a famous periodic comet that appears every 76 years, whereas Ursa Major, Ursa Minor, and Orion are constellations.

Why do we find the Sun to be the biggest and the brightest star?

1. The Sun is the star closest to the Earth, situated at an average distance of about 15 crore km (150,000,000 km or 8.3 light minutes).
2. Other stars are located extremely far away from Earth, at distances of several light years (for example, the next nearest star Alpha Centauri is 4.3 light years away).
3. As observed in Activity 1, distant objects appear much smaller and fainter compared to nearby objects.

Because the Sun is tremendously closer to us than any other star, it appears as the biggest and brightest star in our sky, illuminating the daytime sky so brightly that other stars become invisible.

Why does the Pole Star appear to be stationary?

1. The Earth rotates continuously on its geographical axis from west to east, causing all stars to appear to move across the night sky from east to west.
2. The Pole Star (Dhruvtara) is located directly aligned with the rotational axis of the Earth above the North Pole.
3. Because the Pole Star lies directly on the line of Earth’s axis of rotation, its relative position does not change as the Earth spins. Consequently, it appears stationary in the northern sky throughout the night.

Draw diagrams of the positions of different stars in Ursa Major and Orion.

`

1. URSA MAJOR (SAPTARISHI / GREAT BEAR)

Saucepan / Dipper Shape with 7 Prominent Stars:

[Indicating Stars]

Star 1 ——- Star 2 (Pan Top Edge)

Star 4 ——- Star 3 (Pan Bottom Edge)

/

Star 5 *

Star 6 *

Star 7 * (Handle Tip)

Direction pointer line: Joining Star 4 -> Star 1 -> Points directly to Pole Star in North.

1. ORION (KAL PURUSH / HUNTER)

Hunter Shape with Bright Central Belt:

• (Head)

/

(Shoulder) (Shoulder)

| * | <-- [Hunter's Belt: 3 Bright Stars in a Straight Line]

/

(Foot) (Foot)

`

Explanatory Note:

• Ursa Major (Saptarishi): Consists of 7 bright stars arranged in the form of a saucepan or big ladle. Three stars form the handle of the saucepan and four stars form the pan bowl. The top two stars of the pan (Indicating Stars) form a straight line pointing toward the Pole Star.
• Orion (Kal Purush): Resembles a hunter. It contains seven or eight main bright stars forming the head, shoulders, belt, and legs of a hunter. The three stars arranged tightly in a straight line at the center represent the belt of the hunter.

Venus is not the nearest planet to the Sun. Then why is it the brightest?

1. Mercury is the nearest planet to the Sun, but Venus is the second planet from the Sun.
2. The brightness of a planet depends heavily on its ability to reflect sunlight falling upon its surface.
3. Venus possesses a very dense atmosphere composed of thick clouds that act like a giant mirror, reflecting back about three-fourths (75%) of the total sunlight received by it back into space.
4. Because of this exceptionally high reflectivity (albedo) of its thick cloud cover, Venus shines brilliantly and appears as the brightest planet in the night sky (also visible near the horizon before sunrise or after sunset as the Morning or Evening Star).

How will you recognise the Pole Star?

1. Step 1: Locate the Ursa Major (Saptarishi) constellation in the northern sky during night time.
2. Step 2: Identify the seven stars forming the saucepan shape, specifically focusing on the four stars that form the pan.
3. Step 3: Find the two stars situated at the outer edge/top of the pan, known as the Indicating Stars.
4. Step 4: Imagine a straight line joining these two Indicating Stars and extend it forward towards the north direction.
5. Step 5: This imaginary line leads directly to a bright star that stands still in the north sky; this star is the Pole Star (Dhruvtara).

Write the names of the planets as per their increasing distance from the Sun.

The eight planets of the Solar System arranged in increasing order of distance from the Sun are:

1. Mercury (Nearest planet to the Sun)
2. Venus (Second planet from the Sun)
3. Earth (Third planet from the Sun)
4. Mars (Fourth planet from the Sun)
5. Jupiter (Fifth planet from the Sun)
6. Saturn (Sixth planet from the Sun)
7. Uranus (Seventh planet from the Sun)
8. Neptune (Eighth and farthest planet from the Sun)

Spell out differences between a planet and a star?