Scientists crack mystery of Venus’s vanished water: How electric wind blows oxygen out of the atmosp

Source: Washington Post via National Post

Scientists crack mystery of Venus’s vanished water: How electric wind blows oxygen out of the atmosphere

Ben Guarino, Washington Post | June 21, 2016 11:05 AM ET

By human standards, a descent onto Venus mirrors a fall through different circles of hell. As visitors approach, they would first pass through a thick haze of sulfuric acid. Further below are heavy metal snows that drift over Venusian mountain peaks. Finally, upon touching down, the average surface temperatures — ranging from about 400 to 500 degrees Celsius — would bake explorers like a Neapolitan pizza.

Even the gas molecules from the visitors’ steaming remains would be unwelcome on Venus, eventually blasted out into space thanks to what scientists are calling a strong “electric wind.”

If Earth was born with a twin, out of all the planets in the solar system it should have been Venus. Venus and Earth are the roughly the same size, and millions of years ago Venus possibly had Earth-like oceans. But our sunny-side sister is now arid, its Venusian air up to 100,000 times drier than Earth’s. Chemical hints are all that is left of oceans on Venus. One of the strongest clues is atmospheric deuterium, a form of hydrogen found in earthly seas, which remains on Venus like a chalk outline of long-dead bodies of water.

The lack of oxygen and other ions associated with water is puzzling. If Venus once had liquid water, its molecules should linger in the atmosphere. The grip of gravity does not simply let go, no matter how hot a planet is. Scientists previously thought that the sun, blasting Venus with a stream of particles known as solar wind, had stripped the planet of its steam.

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Read more: http://news.nationalpost.com/news/world/scientists-crack-mystery-of-venuss-vanished-water-how-electric-wind-blows-oxygen-out-of-the-atmosphere

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Source: NASA

June 20, 2016

‘Electric Wind’ Can Strip Earth-like Planets of Oceans, Atmospheres

Venus has an “electric wind” strong enough to remove the components of water from its upper atmosphere, which may have played a significant role in stripping Earth’s twin planet of its oceans, according to new results from ESA’s (European Space Agency) Venus Express mission by NASA-funded researchers.

“It’s amazing, shocking,” said Glyn Collinson, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We never dreamt an electric wind could be so powerful that it can suck oxygen right out of an atmosphere into space. This is something that has to be on the checklist when we go looking for habitable planets around other stars.” Collinson is lead author of a paper about this research published June 20, 2016, in the journal Geophysical Research Letters.

Venus is in many ways the most like Earth in terms of its size and gravity, and there’s evidence that it once had oceans worth of water in its distant past. However, with surface temperatures around 860 F (460 C), any oceans would have long since boiled away to steam and Venus is uninhabitable today. Yet Venus’ thick atmosphere, about 100 times the pressure of Earth’s, has 10,000 to 100,000 times less water than Earth’s atmosphere. Something had to remove all that steam, and the current thinking is that much of the early steam dissociated to hydrogen and oxygen: the light hydrogen escaped, while the oxygen oxidized rocks over billions of years. Also the solar wind — a million-mile-per-hour stream of electrically conducting gas blowing from the sun — could have slowly but surely eroded the remainder of an ocean’s worth of oxygen and water from Venus’ upper atmosphere.

“We found that the electric wind, which people thought was just one small cog in a big machine, is in fact this big monster that’s capable of sucking the water from Venus by itself,” said Collinson.

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Read more: http://www.nasa.gov/feature/goddard/2016/electric-wind-can-strip-earth-like-planets-of-oceans-atmospheres