THE EARTH

The earth is the third planet of the eight planets that orbit the sun . It is the largest and densest rocky planet , and  the only and only one known to support life . About 70 % per cent of the Earth's surface is covered by water , which is not found in liquid form on the surface of any other planet. There are four main layers :the inner core, the outer core, the mantle, and the crust. At the heart of the planet the solid inner core has a temperature of about 4000degree celcius. The heat from this inner core causes material in the molten outer core and mantle to circulate in convection currents. It is thought that these convection currents generate the earth's magnetic field, which extends into spaces as the magnetosphere. The Earth's atmosphere help's screen out some of the harmful radiation from the sun, stops meteorites from reaching the planet's surface, and traps enough heat to prevent extremes of cold. The Earth has one natural satellite ,the Moon , which is large enough for both bodied to be considered a double-planet system