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Apart from the Moon, countless stars are also found in the night sky.
Stars are celestial objects which emit heat and light on their own. They are mainly composed of hot gases, like hydrogen and helium.
The colour of the star denotes its temperature. The hottest stars appear blue, whereas the coolest stars appear red. Our Sun is a white star even though it looks yellow from Earth.
Stars at night sky
The Sun is also a star that appears so large when viewed from the Earth. It is because all the other stars are millions of times farther away than the Sun. Therefore, the other stars appear like white dots in the night sky. It takes millions of years for a star to complete its life cycle. Hence, they appear at a permanent position in the sky.
View of Sun
Visibility and movement of stars:
Because of the bright sunlight, the stars are not visible in the daytime, even if they are present. When a group of stars are observed, they appears to rise in the east in the evening and sets in the west in the early morning. It is due to the rotation of the Earth, which is from west to east. This is the reason why the stars appear to move from east to west.
Twinkling of stars:
The stars seem to twinkle at night because the light emitted by the stars enters the Earth's atmosphere in a zig-zag motion. This is due to the change in density of the space and the different layers of the atmosphere.
Twinkling stars at night
Pole star:
The pole star is situated in the direction of the Earth’s axis, and also it does not appear to move. This star is also known as Polaris or North star. It is visible only from the northern hemisphere. In the given figure, the pole star lies close to the axis of the earth. It cannot be viewed from the southern hemisphere.
Position of pole star from Earth
Sailors find the direction in the middle of the sea with the help of a pole star since it locates the north direction.
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