November 30, 2007

Meanwhile, on Venus...

Lately, Earth and Mars seem to get all the press, but the NASA has ignored Venus since the NASA's Magellan mission used radar to map the planet in 1994 . Venus is Earth's neighbor, on the side closer to the Sun. The planet has roughly the same mass, size, and composition as Earth. Evidence shows that Venus was once partially covered by deep oceans of water. Today, Venus is unimaginably hot, with only a little water left on its surface. How could two planets that were once so essentially alike end up so different?

This week, the European Space Agency (ESA) released eight papers in Nature magazine documenting the findings of the Venus Express mission, their unmanned probe launched in 2005. The ESA has been building their understanding of Venusian weather, which to Earthlings is astounding: above the planet's 460-degree-C surface, the Sun’s energy blasts thick sulphuric acid clouds through an atmosphere that is about 95 percent carbon dioxide.

On Earth, a small amount of atmospheric carbon dioxide warms the surface, which is tempered by vast oceans. On Venus, the thin spots of surface water are vaporizing into space under intense heat. With an atmosphere composed mainly of carbon dioxide, no oceans to cool lava that flows to its surface, and a closer proximity to the sun, Venus experiences an extreme greenhouse effect.

Venus' inhospitable conditions ruins our chances of finding any remaining record of past life there, and makes the possibility of landing an astronaut there a pipe dream. link

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