‘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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