Stars and the solar system Worksheet-7

Stars and the solar system Worksheet-7

 

  1. What are meteorites?

 

  1. What is artificial satellite?

 

  1. What are comets?

 

  1. Differentiate between stars and planets.

 

  1. Why can we not hear any sound on the moon?

 

  1. What do you know about the phases of moon? Why do phases of the moon occur?

 

  1. What is the sun? Name the next nearest star. What is the distance of sun from the earth? Write the unit of the large distances.

 

  1. What are constellations? Explain some common constellations.

 

  1. What is Pole star?

 

  1. Explain the solar system.

 

  1. Explain the following terms:

(a) Asteroids     (b) Comets

(c) Meteors       (d) Meteorites.

 

  1. What are planets? Explain them.

 

Answer:

  1. Meteorites are bits of the solar system that have fallen to the Earth Some meteors are so large that do not completely evaporate before reaching the earth. These are called meteorites.

 

  1. A man made satellite which is orbiting the earth is called artificial satellite.

 

  1. Comets are the member of our solar system. They revolve around the sun in highly elliptical orbit as a bright head a with a long tail.

 

  1. Stars Planets

(i) Stars twinkle in the sky.

(ii) They are fixed at a point.

(iii) They have their own light.

(iv) They are very big in size. (i) Planets do not twinkle in the sky.

(ii) They revolves around the sun.

(iii) They have no light of their own.

(iv) Planets are smaller as compare to star.

 

  1. Moon is natural Satellite of earth. It revolves around the earth. There is no air on the surface of the moon. Sound waves need medium to travel. Without medium it cannot travel from one place to other. So we do not hear any sound on the surface of the moon.

 

  1. The various shapes of the bright part of the moon as seen during a month are called phases of moon. The moon does not produce its own light. Whereas the sun and other stars do. We see the moon because the sunlight falling on it is reflected towards us, we therefore see only that part of the moon, from which the light of the sun is reflected towards us. The moon revolves around the earth so its position changes every day. The moon appears different at different positions. So the phases of moon occur.

 

  1. Sun is the nearest star from the earth. It also emits light like the other stars. The next nearest star is Alpha Centaury. The sun is nearly 150 million km away from the earth. Such large distances are expressed in another unit called light year. The distance traveled by light in one year is called light year. The speed of light is about 300000 km per second. Thus the distance of the sun may be said to be about 8 light minutes.

 

  1. The groups of stars that has a recognizable shape is called constellation. Some common constellation are:

(i) Ursa Major: It appears during summer time in the early part of the night. It is also known as Big Dipper or Great Bear or the Saptrashi. There are seven prominent stars in this constellation. It appears like a big ladle or a question mark.

(ii) Orion: This constellation can be seen during winter in the late evenings. It has seven or eight bright stars. Orion is also called the hunter.

(iii) cassiopeia: It is the most common or 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.

 

  1. The star in the sky which appears stationary and does not move like other stars is called pole star. It is situated above the north pole of the earth.

 

  1. 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 attraction between the sun and these objects keeps them revolving around it. Our earth is also a planet which revolves around the sun. It is also a member of solar system. There are seven other planets that revolve around the sun. The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

 

  1. (a) Asteroids: There is a 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 small objects are called asteroids.

(b) Comets: Comets are also small bodies which revolve around the sun in highly elliptical orbits. They become visible from the earth only when they come close to the sun. They are characterized with a small head followed by long tail.

(c) Meteors: Very small stone like objects are called meteors. They are commonly known as shooting stars, although they are not stars. The meteors occasionally enter the earth's atmosphere. Due to friction they heats up. they glow and evaporate quickly.

(d) Meteorites: The portion of meteor which does not burn during its fall through the earth's atmosphere and hits the ground is called a meteorite.

 

  1. The celestial bodies which revolve around the sun in a certain orbit are called planets. There are following eight planets:

(i) Mercury: The planet mercury is nearest to the sun. It is smallest planet of solar system. It has no satellite of its own.

(ii) Venus: Venus is earth's nearest planetary neighbor. It is the brightest planet in the night sky. Venus has no moon or satellite of its own.

(iii) Earth: It is the third planet.

The earth is only planet in the solar system on which life is known to exist. Earth appears blue green due to the reflection of light from water and landmass. It has only one moon.

(iv) Mars: The fourth planet is Mars. It is called the red planet. Mars has two small satellite.

(v) Jupiter: It is the largest planet of solar system. It is so large that about 1300 earths can be placed inside this giant planet. It has a large number of satellites.

(vi) Saturn: Beyond Jupiter is Saturn, which appears yellowish in colour. It contains beautiful rings which are not visible with naked eyes.

(vii) Uranus: It is the seventh planet. It is second outermost planet.

(viii) Neptune: The outermost planet is called Neptune.