Stars and the Solar System
The stars, the planets, the moon and many other objects in the sky are called celestial objects. Moon is the brightest object in the night sky. Moon revolves around the earth and is the natural satellite of the earth.
There are various shapes of the bright part of the moon which can be seen during a month. We see only that portion of the moon from where the sunlight gets reflected towards us. The size of the illuminated part of the moon visible from the earth keeps on changing every day which leads to phases of moon. On observing the closure view of the moon, it is found that the moon’s surface is dusty and barren.
Stars are the celestial objects that have light of their own. The distance between a star and the earth is measures in light years. Stars appear to move from east to west while the pole star appears stationary when seen from the earth.
Some of the stars are categorised into groups to from a recognisable shape. These groups of stars that appear to form recognisable shapes are called constellations.
The sun is also a star and life source to earth. The eight planets and the sun together constitute our solar system. The gravitational attraction between the sun and these planets keep them revolving around it. The definite path in which planets revolve around the sun is called an orbit. There are some other objects in our solar system which are asteroids, comets, meteors and meteorites and artificial satellites.
Artificial satellites are man-made satellites which are launched from the earth. Artificial satellites revolve around the earth much closer than the moon. Artificial satellites are used for weather forecasting, transmitting television and radio signals, telecommunication and remote sensing.