Fill in the Blanks
1. According to Astronomers, at least billion Galaxies are there in the Universe.
2. …………….. is made up of the Sun and the eight Planets.
3. Scientists estimated that our Solar System was formed about …………….. years ago.
4. Geocentric theory Was proposed by an Egyptian astronomer named …………….. .
5. Heliocentric theory was proposed by the Polish astronomer named …………….. .
6. Every year we celebrate …………….. as ‘World Environment Day’.
7. The solid part of the Earth is called …………….. .
