Add this to the list of reasons Venus is a blistering hellscape: Not only is the surface hot enough to melt lead, not only will the sulphuric acid rainstorms burn gaping holes in your partially-melted spaceship, it also has a monstrous electric wind that appears to have helped strip all the water out of the atmosphere. Good luck gardening in your cloud city.

Artist’s concept of Venus’ electric field. Image: NASA

Scientists have long suspected that all planets with an atmosphere also have an electric field, generated by a layer of charged particles in the upper atmosphere called the ionosphere. But so far, on every planet where we’ve looked, including our own, we’ve been unable to detect it. The working theory is that these electric fields are very, very weak — Earth’s is thought to be in the range of one to two volts.

Venus is different. “Venus’ electric field is enormous — it’s a monster lurking in the sky,” said Glyn Collinson, lead author on a study published yesterday in Geophysical Research Letters which used data collected by the ESA’s Venus Express mission to measure that electric field for the very first time.

Venus’ electric field is at least five times larger than that of Earth, Mars or Saturn’s moon Titan. It’s so strong, in fact, that it produces its own “wind”, which is less like the gusty gales we’re familiar with on Earth and more akin to the solar wind, a stream of charged particles emanating from the sun.

This discovery could help explain why Venus contains a minute fraction of Earth’s water, despite being formed from similar starting materials. When sunlight hits molecules of water vapour in the atmosphere, the jolt of energy causes them to break apart into ions of hydrogen and oxygen. On Venus, the electric wind is strong enough to accelerate those oxygen ions to atmospheric escape velocities.

“If we want to strip the atmosphere, we need to overcome gravity,” Collinson said. Now, we have mechanism for doing exactly that independently of the solar wind, which is typically implicated in atmospheric stripping.

“If you’re able to switch off the solar wind, Venus would still be losing heavy ions and oxygen,” he continued. “That said, the solar wind really helps, and the two interplay together.”

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Do you understand this? I don’t.

The Sun has an electric field, because of the thermionic effect, but it’s remarkably small. The heat tends to preferentially expel electrons rather than protons from the Sun because the electrons are lighted in weight. This is the same effect that causes a heated cathode to be positive in charge. But the resulting electric charge difference drags those electrons back largely negating the effect.

Planets lose gases because of two primary mechanisms. The largest effect is that of sputtering caused by protons and alpha particles in the solar wind. The Earth’s magnetic field partially protects the Earth from this, but not entirely. The second mechanism is called the Jeans mechanism, and is identical to the thermionic effect, heat expels electrons and atomic nuclei from the atmosphere but mostly electrons leading to a slight positive electric charge.

Earth has a magnetic field that partially protects against sputtering. Venus has no such protection. On the other hand, Earth’s magnetic field heats up the ionosphere increasing the atmosphere loss due to the Jeans effect. On Venus there is no ionosphere and the uppermost part of the atmosphere is much colder than Earth’s so there is less Jeans effect and a smaller electric charge.

So Venus ought to have a smaller electric field than Earth and the quoted article makes no sense. Especially when it comes to talking about stripping water out of the atmosphere.

Unless they’re talking about the lower atmosphere, and even there most of the charge in Earth’s lower atmosphere comes from the triboelectric effect associated with hailstones and lightning. Venus also has lightning, but I don’t understand where the electric charge comes from, does Venus have hailstones? The lightning on Venus was detected in 2007 by the Venus Express spacecraft.
http://www.nasa.gov/vision/universe/solarsystem/venus-20071128.html

If the electric charge associated with lightning is 5 volts as opposed to 2 volts on Earth then the amount of lightning would be two to three times more intense, hardly terrifying.