3rd Class Science Solar System Solar Systems

Solar Systems

Category : 3rd Class


This lesson -will help you to: -

  • learn about the solar system
  • know about planets and their unique features
  • learn about our planet Earth and Moon



Solar System

  • The Solar System is made up of the Sun, planets, moons, comets, asteroids, meteoroids minor planets, dust and gas.
  • Everything in the Solar System orbits or revolves around the Sun. The Sun is so large, that its powerful gravity attracts all the other objects in the Solar System towards it.
  • The Sun is the largest object in the solar system.


The sun is in the Centre of the Solar System. It is huge and made up of extremely hot gases. The sun is the main source of heat and light for the solar system. The sun is the nearest star. It is about 150 million km away from the earth.




  • There are now officially only eight planets in our solar system. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Now, Pluto is no longer planet of our solar system.
  • While Mercury is the closest planet to the Sun, Neptune is the farthest planet from the sun.
  • Amongst all planets, Jupiter is the heaviest planet of the solar system.
  • The smallest planet in the Solar System is Mercury. Mercury is only 38% the diameter of Earth.



  • Earth is also known as watery planet, because 70% of its surface is covered by water. The earth's atmosphere scatters the light & creates a blue effect, so it is also called Blue Planet. It is the only planet having life.
  • Earth orbits the Sun once in about 365i Earth days. This is also known as revolution. Due to revolution we experience different seasons.
  • Earth also rotates on its own axis. This is called rotation. It takes 24 hours to complete one rotation and it creates day and night.
  • Earth is the only planet that has an atmosphere containing 21% oxygen. On earth we have liquid water on its surface. It is the only planet in the solar system that has life. Earth has got one natural satellite i.e. Moon. When viewed from space earth seems blue because of the presence of water in it.
  • Due to gravity, the layer of gases known as atmosphere remains attached to it and prevents too much heat or UV rays from Sun reaching earth. Earth reflects about l/3rd of sunlight it receives.


Historical Preview

  • Earlier it was assumed that earth is the solar system. However, astronomers such as Nicolaus Copernicus, Galileo Galilei, Johannes Kepler and Isaac Newton helped develop a new model that explained the movement of the planets with the Sun at the center of the solar System.


Misconcept / Concept

Misconcept: The Solar system only includes the Sun, planets, and moon.

Concept: The Solar System is made up of the Sun, planets, moons, comets, asteroids, meteorites, minor planets, dust and gas.

Misconcept: On full moon day, we can see the moon completely.

Concept: The phases of the Moon are caused by shadows cast on its surface by shadows cast on its surface by shadows cast on its surface by Earth or by other objects in the solar System. We only see one face of the moon.



  • Moon is the only natural satellite of the Earth. It looks bigger to us as it is very close to us.
  • The moon has no atmosphere, so there is huge difference between day and night temperature. As there is no atmosphere, there is no weather, no rain, no wind or clouds on moon.
  • Moon also does not have its own light. It shines due to Sun's light.
  • There is no water on moon's surface.


Did you Know?

  • Moon’s gravity is 1/6th of Earth, so our weight on moon would be 1/6th of our weight on the earth.
  • The Moon is the only celestial body other than Earth on which humans have set foot. Neil Armstrong became the first person to walk on the moon as the commander of the American mission Apollo 11 on 21 July 1969.


Funny Tricks:

  • If you have problems remembering the names of planets in their correct order, just remember this sentence “My very Educated Mother Just Served Us Nuts.” To summarize planets in correct order—Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
  • The Solar system is made up of the Sun, planets, asteroids, moons, comets. It can be remembered as SPAMC or with a statement like “So, please answer my call.”


Amazing Facts

  • The Solar System was formed around 4.6 billion years ago.
  • If you will shout in space, even if someone is right next to you, they wouldn’t be able to hear you, as there is no air to carry your message.
  • Galileo was the first scientist to look at night sky through a telescope.

Other Topics

Notes - Solar Systems
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