Planet Earth and the calendar year

The Earth is the third planet from the Sun, a slightly flattened ball. From space it looks blue and white because oceans and clouds cover much of it, so it is called the “blue marble”. The Earth is covered by a solid crust (lithosphere), and its inside is very hot. The crust is made of big plates that move slowly; where plates collide earthquakes happen. The water shell is the hydrosphere: the World Ocean has 5 oceans (Pacific, Atlantic, Indian, Arctic, Southern). The land parts are continents: Eurasia, Africa, North America, South America, Australia and Antarctica. The highest mountain is Everest (about 8849 m) and the deepest place is the Mariana Trench (about 11 km). The air shell, the atmosphere, surrounds the Earth and protects us from meteorites and harmful rays.