Earth's twin planet Venus is a blistering planet filled with streaks of acidic clouds, a runaway greenhouse effect and a surface hot enough to melt lead.
This second planet from the sun is considered the closest semblance to our own planet because it is slightly smaller, but it's completely different.
For instance, the atmosphere of Venus consists mainly of carbon dioxide, little nitrogen and small traces of sulfur oxide and other gases. Its atmosphere is much thicker than that of Earth and can reach pressures of more than 90 times that of our planet at sea level. It is also extremely dry, with a comparative abundance of water 100 times lower.
But it wasn't always this way. Scientists believe that Venus once contained large amounts of water 4 billion years ago. However, as the planet heated up, much of the water evaporated into the atmosphere. They suspect that the planet's "electric wind" may have helped strip all the water out of the atmosphere.
"Electric Wind"
Astronomers have long been wondering whether all planets with atmospheres have an electric field generated by a layer of particles located in the ionosphere.
But so far, in every planet that they looked, they have been unable to detect it. Their theory is that the electric field is just very, very weak. They even postulate that Earth's electric field is only at a range of 1 to 2 volts.
The electric field of Venus, however, is quite enormous, says Glyn Collinson.
"It's a monster lurking in the sky," says Collinson, who is a NASA scientist and lead author of a new paper that measures Venus' electric field.
The planet's electric field is five times larger than that of Mars, Earth or Saturn's natural satellite Titan. Because it is so strong, scientists say the electric field produces its own "wind." It's very different from the gusts of air we experience, however, as it is more akin to solar wind - a stream of particles coming from the sun.
Researchers say that when molecules of water go up into the atmosphere, light from the sun separates the water into hydrogen ions that easily escape and oxygen ions that are heavier. On Venus, the electric wind is so ferocious that it can accelerate these oxygen ions and cause them to escape the atmosphere.
Co-author Professor Andrew Coates of the University College London Mullard Space Science Laboratory says the ions dragged away into space are lost forever, and that more than 100 metric tons of oxygen ions per year are actually removed from Venus.
Collinson says although they do not know why the electric field is much stronger in Venus, they think its distance to the sun, as well as the ultraviolet sunlight being double in brightness, may be affecting it.
The team used a large instrument aboard the European Space Agency's Venus Express to measure the planet's electric field. Details of the study are published in the journal Geophysical Research Letters on June 20.
