Earth is the third planet from the Sun. The age of the Earth, astronomers, - of 4.54 billion years.
Around the Sun the Earth makes its way at a speed of 30 kilometers per second. People taking part in this movement, you don't feel it. To our planet could fly out of the Solar system and explore in the infinite space, it is necessary to give the speed a little more than 42 kilometers per second. This difference in 12 kilometers per second and protects the Earth from catastrophe that could befall her.
Around the Sun the Earth moves in its orbit, having a form somewhat flattened circle - ellipse. The land in the summer (for the Northern hemisphere) is from the Sun at a distance of 152 million kilometers, and in winter up to 147 million kilometers. We are at noon closer to the Sun in the period from January to July, and from July to January, on the contrary.
The earth consists of a metal core (inside, solid, and liquid), viscous mantle and crust. The mantle makes up 67% of the total Land mass and about 83% of the total Land. The thickness of the crust varies from 6 km under the ocean, up to 30-50 km on the continents.
The Structure Of The Earth
The earth is not a perfectly rigid body. Its surface, like the ocean, experiencing the ebb and flow of the tides under the influence of the Sun and moon. Different parts of the planet are in motion: the rise, fall and even "travel" in the horizontal direction.
His attraction to the Earth holds the surrounding atmosphere, which consists mainly of nitrogen, oxygen, small amounts of impurities (hydrogen, carbon dioxide and others). A characteristic feature of our planet is the abundance of water. Seas and oceans are about 70% of the earth's surface. Water and water vapor plays an important role in the course of geophysical and biological processes on Earth. Liquid water, necessary for the existence of the known forms of life, is no longer on the same planet in the Solar system.
View of Earth from space
The land surrounds the magnetic field, acting as a trap for charged particles coming from outer space. Far beyond the atmosphere of our planet is surrounded by clouds of high-energy particles, forming a field of radiation that protect the globe from the cruel cosmic rays, harmful to all living things.
The planet with the same illumination, temperature and approximately the same size as our Earth, in the Universe occur infrequently. But the universe is so vast that, by conservative estimates, one of our Galaxy there are 10 of thousands of planets resembling Earth. Scientists do not exclude the possibility that some of them life exists.