User:RitaGu/TWA/Earth







=Earth= The Earth is the third planet from the Sun. It is one of the four terrestrial planets in our Solar System. This means most of its mass is solid. The other three are Mercury, Mars, and Venus. The Earth is also called the Blue Planet, Planet Earth, and Terra.

The Earth is home to millions of species of plants and animal, including humans.

Earth is the only planet in the galaxy which is known to support life. Earth has many places that are suitable for humans to live, although some areas of the planet can be dangerous for humans or uninhabitable.

The Earth is divided into several layers which have distinct chemical and seismic properties (depths in km):

0- 40 Crust

40- 400 Upper mantle

400- 650 Transition region

650-2700 Lower mantle

2700-2890 D '' layer

2890-5150 Outer core

5150-6378 Inner core