The Solar System (Class 8)

The Solar System 

Q. Write a short note on each:

I) Sun

  • The sun is at the centre of solar system. It is the nearest star from us.
  • Like all the stars the sun produces energy by transforming hydrogen into helium. Through a series of complex nuclear reactions, two hydrogen protons combine to form a helium atom. This reaction produces an enormous amount of energy. Hence, the Sun is the main source of heat and light for all the planets.
  • The diameter of sun is 109 times the diameter the diameter of Earth. In volume it is 1.3 million times bigger than earth.
  • Gravitational pull of the sun is 28 times the gravity of the Earth. A body weighing 1 kg on the Earth will weigh 28 Kg on the Sun.
  • The sun rotates on its axis as the earth does. The sun completes one rotation in about 25 days. It also revolves around the centre of galaxy once in 225 million years.

II) Mercury (Budh)

  • It is nearest planet to the Sun and the smallest planet present in our solar system.
  • It is very difficult to observe it, as most of the time it is hidden in the glare of the Sun.
  • Mercury has no satellite of its own.

III) Venus (Shukra)

  • It is nearest planet to Earth and it is the brightest planet visible in the night sky.
  • It is also called a morning or an evening star, although it is not a star.
  • Venus rotates on its axis from east to west.
  • Venus has no moon or satellite of its own.
  • A day of Venus is longer than its year.

     IV) Earth (Prithvi)

  • It is the only planet in the solar system on which life exists. Some special environmental conditions are responsible for the existence and continuation of life on the Earth. These include just the right distance from the Sun, so that it has the right temperature range, the presence of water and suitable atmosphere and a blanket of ozone.
  • Earth appears blue green due to the reflection of light from water and landmass on its surface.
  • The axis of rotation of the Earth is not perpendicular to the plane of its orbit. The tilt is responsible for the change of seasons on the Earth. 
  • It has only one moon or satellite of its own.

V) Mars (Mangal)

  • It looks somewhat reddish and, so, it is also known as the red planet.
  • Mars has two small natural satellites.

VI) Jupiter (Brihaspati)

  • It is the largest planet of the solar system. It rotates very rapidly on its axis.
  • Jupiter has a number of natural satellites (79 satellites) and also has faint rings around it.
  • It is about 1300 times larger than that of earth and its mass about 318 times than that of our Earth

VII) Saturn (Shani)

  • It is yellowish colored planet.
  • There are beautiful rings around this planet, which are not observed in any other planets.
  • It is the least dense among all the planets. Its density is less than that of water.
  • It is a planet with maximum natural satellites (82 satellites).

VIII) Uranus 

  • Uranus also rotates from east to west. 
  • It is the one of outermost planet of the solar system. 
  • The most distinctive feature of Uranus is that it has highly tilted rotational axis.
  • It has 27 natural satellites.

IX) Neptune 

  • It is the outermost planet of the solar system that means farthest planet from Sun.
  • It is the coldest planet.
  • It has 14 natural satellites.

 

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