Hello everyone let’s start with chapter number one of geography the earth as a planet. students in the earlier days it was believed that the earth  was the center of the universe. do you believe it and all the heavenly bodies of the universe we’re moving around it however today it is an accepted fact that Earth is one of the eight planets that moves around the Sun. the Sun is one of the many stars in the universe clusters and start forming a narrow band in the sky are called as galaxies. The word cluster means a group of similar things all occurring closely together and galaxies is formed by clusters of billions of stars the Sun and it’s planets together from the solar system in the solar system is the part of the Milky Way galaxy now let’s gather information about the Sun as a star. The sun like all the stars is a hot ball of gas. the diameter of the sun measures 13 lakh ninety two thousand kilometers and students believe me the diameter of the sun is hundred and ten times larger than that of the earth even the volume of the Sun is 1.3 million times larger than that of our planet earth. the outer layers exert great pressure towards it core or the innermost layer this is because of the huge size of the Sun. Nuclear fusion takes place here due to the great heat nuclear fusion is nothing but a nuclear reaction in which two or more atomic nuclear collided at a very great speed  and they join to form a new type of atomic nucleus in the case of Sun the nuclear fusion process turns the hydrogen gas into helium gas and therefore releasing large amount of energy this process occurs in the innermost part of the Sun that is the core of the Sun. the energy which is really is in all direction is in the form of electromagnetic waves these include infrared rays ultraviolet rays as well as radio waves there are larger dark spots on the surface of the sun for example the one which you see highlighted on the screen they  appear dark because they are cooler and they have lower temperature than the surface of the sun these dark spots are called as the sun spots. a typical galaxy may contain one lakh million stars the Milky Way galaxy the galaxy to which our sun our solar system belongs to is called as our galaxy or we also call it as the home galaxy now let’s get that information about difference between the planet and star. the stars like the Sun radiates heat as well as light planets have no light of their own this stars are large burning masses which are located very far away from us the planets are solid bodies nearer to us. The star moment is very slow in comparison to the planets all the planets revolve around their stars in a fixed path and this path we normally call it as orbit. The stars make large clusters which we call s galaxies a typical galaxy we already know contains more than one lakh million starts the Milky Way to which our son belongs to is called as our galaxy or the home galaxy. Planets do not make any such clusters.