What is the hypothesis of Snowball Earth?

The

Snowball hypothesis Earth refers to the idea that at some point during the country's history, specifically during the cryogenic period (850 to 630 million years ago), the entire surface was frozen, including the oceans. The Snowball Earth hypothesis is controversial among paleontologists, but many believe that it helps to explain the presence of glacial deposits in tropical latitudes from this period and other unusual aspects of cryogenic geological record. All scientists agree that there have been huge glacies in the cryogenic period, the disagreement is whether they have become global. This would cause rapid weathering of continental rocks, which would then absorb a large amount of atmospheric carbon dioxide. Because carbon dioxide is a greenhouse gas that plays essential in maintaining the ground in the heat would cause this exhaustion to escape the accumulation of ice. When the glaciers covered the ground, Albedo Earth (reflectivity) would increase and reflect the light energy back into space and further accelerate cooling. EventuallyThe result would be completely covered with ice, with equatorial temperatures similar to today's Antarctica.

To distract deep freezing of the snowball, a large amount of carbon dioxide would require. As silicate and carbonate rocks, normal sources of carbon dioxide would be completely covered, the gas would have to come from volcanic explosions. Over time periods in millions of years, volcanic explosions would sufficiently place in the CO2 atmosphere to start global warming. This warming would cause melting the ice around the equator, sing positive warming feedback.

Some scientists believe that the hypothesis "Slushball Earth" is more realistic than the snowball of the Earth, where there would be an area of ​​a thin ice or icy ocean around the equator. This is necessary for the active hydrological cycle and some geological bearings from the time indicate the presence of one.

Snowball Earth is nSometimes quoted as retention of multicellular life, but the truth is that we do not know whether it is true or not. The unicellular life certainly existed a billion years before the cryogen and survived, perhaps in deep hydrothermal ventilation openings and other refuge. The survival of earthly life in the Snowball Earth is sometimes cited as an argument that life could exist in the ice -covered oceans of the body of the outer solar system, such as Jovian Moon Europa.