CBSE Class 6 Geography Chapter 1 Notes Understanding The Lesson

1. We can not see the moon and all those bright objects of the sky in the day time. It is because the very bright light of the Sun does not allow us to see all these bright objects of the sky.

2. The Sun, the moon and all those objects shining in the sky are called celestial bodies. Celestial bodies are made up of gases. Some are very big and hot. They have their own heat and light, which they emit (release) in large amounts. These celestial bodies are called stars. The Sun is a star. Countless stars are very very far from us, so we do not feel their heat or light.

3. Different groups of stars form different patterns. These are called constellations. Ursa Major or Big Bear is one such constellation. One of the most easily recognizable constellations is the small bear of Saptarishi (seven sages). It is a group of seven stars.

4. In the ancient times, people used to determine directions during the night with the help of stars. The North Star indicates the north direction. It is also called the Pole Star.

5. Some celestial bodies do not have their own heat and light. They are lit by the light of the stars. Such bodies are called planets. The Earth is a planet. Like the Earth there are eight other planets that get heat and light from the Sun. Some of them have their moons too.

6. Sun is in the centre of the solar system. It is made up of extremely hot gases. It provides pulling force that binds the solar system. The Sun is ultimate source of heat and light for the solar system. The Sun is about 150 million km away from the Earth.

7. There are eight planets in our solar system. In order of their distance from the Sun they are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

8. The easy way to memorize the name of planets in order of their distance from the Sun is: My Very Efficient Mother Just Served Us Nuts. Always remember that first ‘M’ is for Mercury.

9. All the eight planets of the solar system move around the Sun in fixed path. These paths are elongated. They are called orbits.

10. The Earth is the third nearest planet to the Sun. In size it is the fifth-largest planet. Its north and south poles are slightly flattened. This shape is described as Geoid. It has water and oxygen. Its 2/3 surface is covered by water. Its outer surface looks blue. It is, therefore, called a blue planet.

11. The moon is only one satellite of the Earth. Its diameter is only Vi that of the Earth. It is nearer to our Earth than other celestial bodies. It is about 3.84 lakh km away from us. The moon moves around the Earth in about 27 days. It has neither water nor air. It has mountains, plains and depressions on its surface.

12. Asteroids also move around the Sun. These are numerous tiny bodies which are found between the orbits of Mars and Jupiter. Scientists are of the view that asteroids are part of a planet which exploded many years back.

13. Meteoroids are small pieces of rocks which move around the Sun.

The Earth in the Solar System Class 6 CBSE Notes Important Terms

Celestial bodies: The Sun, the moon and all those objects shining in the sky are called celestial bodies. Celestial bodies are made up of gases.

Stars: Celestial bodies are called stars. The Sun is a star. In other words, the Sun and the twinkling objects that we see at night are called stars.

Galaxy: A huge system of millions of heavenly bodies and stars like the Milky Way form a galaxy.

Full moonlight: When moon appears full and looks in the form of a ball. Full moon light is also called ‘Poornima’.

New moonlight: When moon is not seen from the Earth. This night is also called ‘Amavasya’.

Constellation: Constellation is design or pattern of stars. In the sky, during the night, a group of stars form various patterns and designs.

Planet Satellites: Heavenly body that revolves around a planet in the same way as planets revolve around the Sun.

Orbit: The elliptical paths on which the planets and satellites revolve round the Sun are known as orbits.

Asteroids: There are numerous tiny bodies which revolve around the Sun. These are found between the orbits of Mars and Jupiter. These bodies are called Asteroids.

Meteoroids: The small pieces of rocks which revolve around the Sun are called meteoroids.

Pole Star: The North Star indicates the north direction. It is also called the Pole Star.

Geoid: North and south poles of the Earth are slightly flattened. This shape of Earth is described as Geoid.