Frank Cce Everyday Science Solutions for Class 8 Science Chapter 17 Stars And The Solar System are provided here with simple step-by-step explanations. These solutions for Stars And The Solar System are extremely popular among class 8 students for Science Stars And The Solar System Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Frank Cce Everyday Science Book of class 8 Science Chapter 17 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Frank Cce Everyday Science Solutions. All Frank Cce Everyday Science Solutions for class 8 Science are prepared by experts and are 100% accurate.

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(a) astronomy
Astronomy is the science of studying the universe.

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(a) Ursa Minor

Pole Star is a part of Ursa Minor.

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(c) Asteroids

Large number of rocks that lie between the orbits of Mars and Jupiter are called asteroids.

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(a) Venus

Venus is called the morning star.

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(b) stars
Stars have their own light.

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(b) 9.46 × 1012 km
One light year is equal to 9.46 × 1012 km.

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(c) Hydrogen and helium
Hydrogen and helium are the two main gases present on the Sun.

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Question B.8:

The brightest planet in the sky is
(a) Venus
(b) Mars
(c) Mercury
(d) Jupiter

Answer:

(a) Venus
Venus is the brightest planet in the sky.

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(a) Saturn
Saturn is the second largest planet in the solar system.

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(a) Orion
The shape of Orion is like the body of a hunter.

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1. The Great Bear Constellation is also known as the Ursa Major.
2. The Halley's comet can be seen from the earth every 76 years.
3. The first satellite put up by India was Aryabhatta .
4. Stars emit their own light.
5. The sun is the nearest star to the earth .
6. Light year is the unit of distance.
7. The unburnt part of a meteor which reaches the earth is called meteorite.
8. A group of stars which resembles an animal or some other known object is called a constellation.
9. The orbit of Pluto is not in the same plane as that of other planets.

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Column A Column B
1. Red planet (g) Mars
2. Ring of gases (e) Saturn
3. Galaxy (a) Milky way
4. Pole star (d) Ursa Minor
5. Orion (f) Hunter constellation



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Question 1:

The radius of Jupiter is 11 times the radius of the earth. Calculate the ratio of the volumes of Jupiter and the earth.
How many earth can Jupiter accommodate?

Answer:

 Let radius of the Jupitor be r,. According to the question:r,=11 r Volume of the material with radius r=43πr3Volume of Earth, V=43πr3Volume of Jupitor, V,=43πr,3                          V,=43π(11r)3Ratio of volumes = 43π(11r)343πr3=1331:1 

Thus, Jupitor can accommodate 1331 Earths in it.

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The moon cannot be used for communication because of the following reasons:
1. The time taken by the moon to revolve around the earth is not equal to the rotation time of the earth on its axis.
2. The distance between the earth and moon is very large; therefore, a communication signal would take around 2.7 seconds to reach the moon and return. Most forms of communication require a lesser delay than this to function.
3. The moon is very far from the earth; therefore, it is very difficult to maintain a communication station there.

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Question 3:

Light travels with a speed of 3 × 108 m/s in vacuum. Sunlight takes 8.3 minutes to reach the earth. Calculate the distance between the earth and the sun.

Answer:

 Given:  Speed of light =3×108 m/s Time taken by light to reach the earth=8.3 minutes      8.3 minutes=8.3×60 s                        =498 sSpeed=DistanceTimeDistance =Speed × TimeDistance =3×108 m/s ×498 s                =1494 ×108 mThus, the distance between the sun and the earth is (1494×108) m.

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The phases of moon occur because of the relative positions of the earth and the moon with respect to the sun. As the moon revolves around the earth and earth, around the sun, the sun illuminates different parts of moon, which are visible from the earth.

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No, we cannot light fire on Moon because it has no atmosphere (oxygen). For combustion, supply of oxygen is essential.

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Any sound needs a medium to propagate. We cannot hear the sound of a meteor falling on the moon because there is vacuum between the earth and the moon, through which sound cannot propagate.

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Meteoroids are small metallic or rocky bodies that travel across the space. When they enter the earth's atmosphere, they start burning due to friction produced because of resistance provided by the atmosphere. These burning meteoroids are called meteors. There is no atmosphere on the moon; therefore, we cannot see a meteor falling on the moon.

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Life cannot exist on the moon because:

1. The moon has no atmosphere; therefore, oxygen and carbon dioxide are not present there. The presence of these gases is necessary for existence of life.

2. Due to the absence of atmosphere, climate on the moon is not suitable for life. Temperature becomes too low when sunlight does not fall on the moon and extremely high when light falls no it.

3. Water is essential for life to exist, but it is not available on the moon.

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Saturn is made up of gases and its density is less than water. Any material with density less than water floats in water; hence, Saturn will float in water.

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Question 10:

Suppose a star is 100 light years away form earth and explodes. It is highly unlikely that you are able to see the explosion. Explain your answer.

Answer:

One light year is the distance travelled by light in a year. So, if a star, 100 light years away from the Earth, explodes, it is highly unlikely for us to see the explosion, as the light from the site of explosion will reach the earth only after 100 years, thus, the explosion will be visible on earth only after 100 years.

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1. False
Mercury is the hottest planet of the solar system.

2. False
Sun emits its own light.

3. False
Galaxy is the vast collection of stars but not all of them have a recognisable shape.

4. True

5. False
The Halley's comet  appears in the sky after a cycle of 76 years.

6. False
Pole star is not the nearest star to the solar system. Proxima centauri  is the nearest star to our solar system.

7. True

8. False
Meteorite is a part of meteor that reaches the Earth's surface, whereas meteors do not reach the Earth's surface.

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Our solar system belongs to the Milky Way Galaxy.

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Jupiter is the largest planet of the solar system.

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INSAT-1B and INSAT-1C are the artificial satellites that are used in weather forecasting.

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The sun is the brightest known star.
Note: Next to sun, the star that appears brightest from the earth is, Sirius.

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Light year is a unit of distance. One light-year is defined as the distance travelled by light in vacuum in one year.

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The sun is the nearest star to the earth.

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Mercury is the nearest planet to the sun.

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The moon is the only natural satellite of the earth.

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Pole star, also called Polaris, is the brightest star of Ursa Minor constellation (present at the end of the handle of Ursa Minor). It is aligned with the Earth's axis of rotation and therefore its apparent position remains fixed in the sky. For this reason, it is used by sailors for navigation purpose as an indicator of geographical north pole.

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 Venus is visible as an evening star in the west.

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No, the stars in the sky do not move. The earth rotates from west to east on its axis. Hence, all the stars in the sky (except the Pole star) appear to move from east to west. With reference to the earth, the pole star does not appear to move because it is located in the north direction above the earth's axis of rotation. It appears stationary.



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The direction of Pole star in Ursa Major can be guessed with the help of pointer stars. Pointer stars point towards the direction of Pole star, as shown in the diagram.

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A group of stars that forms a recognisable figure or shape is called constellation. A constellations resemble shapes of some animals or humans.

Three types of constellations are:
1. Ursa Major
2. Orion
3. Scorpio

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Stars are the luminous objects which consist of large masses of hydrogen and appear as a lighting object in the sky.
Examples of stars are the Sun, Pole star, etc.

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Comets are the heavenly bodies, usually spherical in shape. They develop tails when they come near the sun. Comets become visible when they are close the earth.

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Meteors Meteorites
When meteoroids enter the earth's atmosphere, they start burning due to friction generated by atmosphere. These meteoroids are called meteors. Meteorites are the remains of meteors that do not burn completely in the atmosphere.
They do strike the earth's surface. They crash on the earth's surface.

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Light year a unit of distance. One light year is equal to the distance travelled by light in one year. Mathematically, one light year equals, 9.4605284 × 1015 meters.

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Stars are hot bodies consisting of large masses of hot gases such as hydrogen and helium. Due to high temperature, they emit large amount of energy in the form of light and heat. As they are far from the earth, their heat does not reach us.

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Stars     Planets Satellites
Stars remain stationary but they appear to move in the sky due to the rotation of the earth. Planets revolve around the sun in a fixed orbit. Satellites revolve around the planets.
Stars emit their own light. Planets do not emit their own light. They just reflect the light of the sun. Satellites do not emit light at all.
They twinkle in the sky. They do not twinkle in the sky. They do not twinkle in the sky.

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Our solar system consists of the sun and all the planets that revolve around the sun. It also consists of the moon, asteroids, comets, minor planets, dust and gases.

The sun is a perfect sphere with a diameter of about 13,84,000 km. It is made up of hot gases like hydrogen and helium and has a temperature of 6000° C. Its centre is very hot with the temperature of 14 x 106 °C. It is the closest star to the earth.

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A group of stars forming some kind of recognisable figure or pattern is known as a  constellations.
There are 88 constellations in the sky. Some constellations form shapes resembling some animal or human being. For example, Orion constellation forms the shape of a hunter, Scorpio constellation looks like a scorpion.

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Question C.4:

Do comets always maintain the same mass? Explain your answer.

Answer:

No, comets do not always maintain the same mass. Comets keep moving around the sun. When they come near the sun, some of their material melts down and vaporises, forming a tail of gases that cause loss of mass.

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Star Planet
They emit their own light. They just reflect the light from sun falling on them.
They twinkle in the sky. They do not twinkle in the sky.
They remain fixed in the sky but appear to move because of the rotation of the earth. They revolve around the sun in fixed orbits.
They do not have satellites.  They have satellites that revolve around them.

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Stars   Planets Satellites
Stars remain stationary but they appear to move in the sky due to rotation of the earth. Planets revolve around the Sun in fixed orbits. Satellites revolve around the planets.
Stars emit their own light. Planets do not emit their own light. They just reflect the light of the Sun. Satellites also do not emit light. They reflect the light of sun falling on them.
They twinkle in the sky. They do not twinkle in the sky. They do not twinkle in the sky.

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A group of stars forming some kind of recognisable figure or pattern is known as a constellations.
There are 88 constellations in the sky. Some constellations form shapes resembling some animal or human being. For example, Orion constellation forms the shape of a hunter, Scorpio constellation looks like a scorpion.

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Satellites are the objects (artificial or natural) that revolve around a planet. Artificial satellites are used for the communication process.
 

Natural satellite Artificial satellite
A natural satellite is a celestial body that revolves around a planet. The satellites that are constructed by human beings and launched from the earth into its orbit, are called artificial satellites.
 Moon is a natural satellite to the Earth. Sputnik-I is an example of an artificial satellite. It was the first satellite to be launched from earth.
 
Artificial satellites are useful to us in the following ways:
1) They help in telecommunication.
2) They help in television and radio signal transmission.
3) They help us study and forecast weather.
4) They help in locating minerals and studying the agricultural yield on the earth.
5) They help scientists to understand the universe by collecting various information from space.

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Question C.9:

Does the surface of Moon look like the surface of the Earth? Describe it.

Answer:

No, the surface of the moon does not look like the surface of the earth. There are differences between their surfaces.
Due to the lack of atmosphere, meteoroids keep falling on the moon's surface; hence, its surface has many craters. Tectonic plates are absent on the moon surface, which makes its surface much different from the earth.

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Question C.10:

Draw diagrams of various constellations and mention the month of their appearance.

Answer:

The Scorpio constellation appears during the summer season.


Ursa Major or Great Bear is a constellation that appears during the summer season.


The Cassiopeia constellation appears during the winter season.

The Orion constellation appears during the winter season.



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