Strong ’electric wind’ strips planets of oceans and 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 the planet of its oceans, according to a new study by NASA and UCL researchers. "It's amazing and shocking," said Dr Glyn Collinson, previously at UCL Mullard Space Science Laboratory and now a scientist at NASA's Goddard Space Flight Center. "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 definitely has to be on the checklist when we go looking for habitable planets around other stars." The study, published today in the journal Geophysical Research Letters , discovered that Venus' electric field is so strong that it can accelerate the heavy electrically charged component of water - oxygen - to speeds fast enough to escape the planet's gravity. When water molecules rise into the upper atmosphere, sunlight breaks the water into hydrogen ions which are fast and escape easily, and heavier oxygen ions which are carried away by the electric field. Co-author, Professor Andrew Coates of UCL MSSL, who leads the electron spectrometer team, said, "We've been studying the electrons flowing away from Titan and Mars as well as from Venus, and the ions they drag away to space to be lost forever. We found that over 100 metric tons per year escapes from Venus by this mechanism - significant over billions of years.