Our Solar System Go Back Explanation views 3:22 Now students find out the meaning of the following words. Look up these words in a dictionary. eg. surface, Space, Envelope, Spacecraft, Astronauts, Star. In our solar system there are total nine planets. Their names as are following. eg. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.1) Mercury: - Mercury is the closest planet to the Sun. Mercury is quite smaller than Earth. Mercury has almost no atmosphere. We can see Mercury with naked eyes just before sunrise and just after sunset, because at all other times it is masked by brightness of Sun. Introduction and Explanation Explanation of Earth Explanation Activity