Water on Venus
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Venus is a burning-desert world hidden under bitter clouds of sulfuric acid and carbon dioxide. It may once have been awash with oceans of near-boiling water.
For hundreds of millions of years, most of the water on Venus was liquid near the boiling point. But the water finally dried up, according to scientists at NASA's Ames Research Center in Mountain View, California, south of San Francisco.
In what they call a moist-greenhouse or wet-greenhouse effect, the water on Venus was able to remain liquid for a few hundred million years because planet temperatures actually were cooler than Earth scientists once thought, and because of the proportion of carbon dioxide to water vapor in the atmosphere of Venus.
Venusian seas dried up slowly as hydrogen eventually escaped into space. Oxygen formed compounds with other elements and was incorporated into the planet's crust.
Scientists say liquid water seems essential to life. The Ames researchers said the oceans of Venus might still have been liquid at 200 to 300 degrees Fahrenheit because of intense pressure. But that may have been too hot for life to begin. If not, it may not have lasted long enough for life to begin.
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