Whether the water is over the earth?

        Human circulatory system is a closed circuit, pokotoroy continuously flowing blood, carrying oxygen and carbon dioxide, nutrients and waste products. This stream never ends, because a circle or ring, as is well known, "there is a ring at the end." By the same token arranged and water network the planet. The water in the world is in a constant cycle, and decline it in one link immediately replenished at the expense of the income from the other. The driving force of the water cycle is solar energy and gravity. Due to the water cycle all of the hydrosphere is closely united and link other parts of nature. In the most general form of the water cycle on the planet looks like. Under the action of sunlight, water evaporates from the surface of the ocean and the land and enters the atmosphere, with the evaporation from the land surface is carried out as rivers and ponds as well as soil, plants. Some of the water is returned immediately to the rain back into the ocean, and a part carried by the wind to the land where the falls as rain and snow. Once in the soil, water is partially absorbed into it, adding to reserves of soil moisture and groundwater flows partly on the surface of rivers and reservoirs, soil moisture is partially transformed into plants, which it evaporated into the atmosphere, and partly flows into the river, but at a slower rate. Rivers feeding water from surface streams and groundwater, carry water into the oceans, filling its decline. Water evaporates from its surface, again in the atmosphere, and the cycle closes. The same movement of water between all components of nature and all areas of the earth surface is constantly and continuously for many millions of years.

        I must say that the water cycle is not completely closed. Part of it getting into the upper atmosphere, is decomposed by sunlight off into space. But these minor losses constantly replenished at the expense of inflow of water from the deep layers of the earth during volcanic eruptions. Due to this volume of the hydrosphere is gradually increasing. According to some estimates 4 billion. Years ago, it was the amount of 20 million. Km3, ie, I was seven thousand times smaller than modern. In the future, the amount of water in the world, apparently, will also increase, given that the volume of water in the Earth's mantle is estimated at 20 billion. Km3 - is 15 times the volume of modern hydrosphere. By comparing the amount of water in parts of the hydrosphere with the influx of water in them and the neighboring parts of the cycle, it is possible to determine the activity of water exchange, ie, the time in which can fully upgrade the volume of water in the oceans, in the atmosphere or the soil. The slowest updated water in polar ice caps (once in 8 th. S). And most rapidly updated river water, which in all the rivers of the world changes completely in 11 days.