8th Class Science Stars and the Solar System Notes - Stars and the Solar System

Stars and the Solar System

·                     The stars, the planets, the moon and many other objects in the sky are called celestial objects.

·                     The moon looks different everyday when seen from a particular place. The various shapes of the bright part of the moon as seen during a month are called phases of the moon. The phases of the moon occur because we can see only that part of the moon which reflects the light of the sun towards us.

·                     Phases of moon occur due to the movement of moon around the earth.

·                     Stars emit light of their own while planets do not have their own light.

·                     Celestial bodies are generally situated very far from each other. Such large distances are expressed in light years. For example, the distance between the earth and the star named Alpha Centauri is 4.3 light years (approximately 40,000,000,000,000 km).

·                     All stars appear to move from east to west but the pole star appears to be stationary from the Earth as it is situated close to the direction of the axis of rotation of the Earth.

·                     The groups of stars that appear to form recognisable shapes are called constellations. Ursa Major, Ursa Minor. Great Bear, Orion, Cassiopeia are some well-known constellations.

·                     The solar system consists of eight planets, numerous moons, and lots of asteroids, comets and meteors.

·                     A body revolving around another body is called a satellite. Satellites are of two types - (i) natural and (ii) artificial

·                     Moon is the natural satellite of the Earth. Some other planets also have natural satellites.

·                     The satellites made by man are called artificial satellites. These artificial satellites revolve around the earth. They are used for weather forecasting, remote sensing and various other purposes.

·                     Mercury is the planet nearest to sun.

·                     The brightest planet in the night sky is Venus. It is also the hottest planet of our solar system.

·                     The largest planet of the solar system is Jupiter.

·                     Saturn is the sixth planet from the sun and the second largest planet in the solar system, after Jupiter It has a prominent ring system. It is less dense than water.