CLASS- 6 S.S.T (भूगोल) (MEDIUM-ENGLISH)

 

CHAPTER- 1 THE EARTH IN THE SOALR SYSTEM

NOTES

1. We can see the full moon about once a month. This is the night of the full moon or Purnima. Fifteen days later, it cannot be seen. This is the night of the new moon or Amavasya.

2. Celestial bodies– The Sun, the Moon, and all the objects that shine in the sky at night are called celestial bodies.

3. Star– Some celestial bodies are large in size and hot. They are made up of gases. They have their own heat and light, which they emit in large amounts. These celestial bodies are called stars.

4. Constellation– While looking at the night sky, you can see various shapes formed by different groups of stars, such as Ursa Major (Big Bear).

5. Pole Star– It always remains at the same position in the sky. The North Star indicates the north direction.

6. Planet– Some celestial bodies do not have their own light and heat. They shine by reflecting the light of stars. Such bodies are called planets.

• A planet is called "Planet" in English. It is derived from the Greek word Planete, which means wanderer or one that moves around.

7. Solar System– The word Solar means related to the Sun. Hence, the Sun's family is called the Solar System.

The Sun is the head of our Solar family.

A) Sun– The Sun is located at the center of the Solar System. It is the only source of light and heat for the Solar System. Even though it is the closest star to us, it is still very far from us. The Sun is approximately 150 million kilometers away from Earth.

B) Planets– There are eight planets in our Solar System. In order of their distance from the Sun, the planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

• Orbit– All eight planets of the Solar System revolve around the Sun in a fixed path. These paths are elliptical in shape and are called orbits.

C) Earth– Earth is the third planet from the Sun in terms of distance. It is the fifth largest planet in the Solar System. It is slightly flattened at the poles, which is why its shape is called Geoid. The term Geoid means Earth-like shape.

• Earth is neither too hot nor too cold. It has water and air, which are essential for life. That is why Earth is the most unique planet in the Solar System.

• From space, Earth appears blue in color. About two-thirds of its surface is covered with water. That is why it is called the Blue Planet.

D) Moon– Our Earth has only one natural satellite, the Moon. Its diameter is only one-fourth of Earth's diameter.

• Neil Armstrong was the first person to set foot on the surface of the Moon on July 20, 1969.

• The Moon completes one orbit around the Earth in approximately 27 days. In the same duration, it also completes one rotation on its own axis. As a result, we can see only one side of the Moon from Earth.

E) Asteroids– Besides stars, planets, and satellites, countless small celestial bodies also orbit the Sun. These bodies are called asteroids.

F) Meteoroids– Small pieces of rock that orbit around the Sun are called meteoroids.

G) Galaxy– A galaxy is a system of millions of stars, clouds, and gases.

8. Universe – Millions of galaxies come together to form the Universe.

• Its immense vastness is extremely difficult to imagine.