Planet Earth

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Each planet of the Solar system is unique in its own right, yet Earth has a whole set of really unique features. First, it is the only active planet - the earthquakes and volcano eruptions constantly change its appearance.
Second, it is the only planet that boasts vast resources of liquid water: its too hot for that on Venus and too cold on Mars. The Earths atmosphere is also very unlike any other planets gaseous shells. Earth neighbors atmospheres consist mainly of carbon dioxide, while the Earths contains great amounts of oxygen and nitrogen, which form shield from the most dangerous components of solar radiation. The Earths atmosphere also protects the planet from meteorites. More so, it is this unique combination of constantly changing land surface, oceans and aerial shield that made it possible for another unique phenomenon - Life -to exist on Earth.
Grand Canyon: the stream cut through the layers of soft sandstone and limestone in Arizona (USA) into a gigantic valley. The maximum depth is 1, 9 km.
Mississippi Delta: the river Mississippi collects a great amount of sediments along its long run and then drops them in the Gulf of Mexico. This slow river leaves these sediments in the mouth, thus creating areas of new land that didnt exist before.
Each 24 hours the Earth completes a full revolution around its axis, which is inclined by 23. 5 to the vertical. This inclination is the reason why the seasons change on the Earth as it rotates around the Sun.
The central part of Earth is a metal core; its very hot - some 4000 C, and its surrounded by a shell of liquid iron that creates the magnetic field of Earth.
Outer layers form the mantle made up of rocky substances, over which are lighter substances that form the crust. The atmosphere is made of nitrogen (77%), oxygen (21%), and a mixture of water vapor and other gases.
The rotation of Earth around its axis generates forceful electrical currents in the iron core of the planet and this creates the magnetic field. This field forms a giant bubble in the near-Earth space called the magnetosphere. Magnetosphere protects Earth from the solar wind - a flow of charged particles emitted by the Sun.
These particles are trapped by the magnetic field in two huge rings - Van Allens belts. When spacecrafts travel through the Van Allens belts, the electrical equipment of the former may suffer malfunction caused by these particles.
Clashing Continents The Earth crust is made from parts called plates, which float on its surface driven by the flows in the liquid mantle. The continents lie on these plates, and so their location is subject to constant change. Some 200 million years ago, all the dry land on Earth was a single continent called Pangea by the scientists, which further split into the continents we know now. The lava rises by millimeters around the mountain ridges located on the ocean floor, and moves the continents apart. When the continents clash, as they do around ...


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