The night sky it is the outer space it is our universe it is called the Milky Way. There are 8 planets in our solar system the biggest is Jupiter, and the smallest is Mercury. Pluto is the dwarf planet not really a planet but it is Earth is the planet we live in and it has atmosphere which has 21% of Oxygen and 78% nitrogen. That makes us live without those we cannot live, we also have approximately 100 billion stars in our Milky Way galaxy  .