Scientists studying data garnered from studying Venus have found that an “electric wind” may have been a key culprit in the theft of that planet’s now-nonexistent oceans. That same “electric wind” is believed to have also torn away water components from the atmosphere and left the thick envelope that currently surrounds the Solar System’s hottest world, contributing to the depletion of the oceans.
Phys.org reported June 20 that NASA researchers, using data from the European Space Agency (ESA)’s Venus Express mission along with computer models, have found that the electric field around the second planet is five times stronger than that around Earth. Venus’ thick band of clouds are 100 times more pressurized than Earth’s atmosphere, which contributes to the planet’s average surface temperature of 860 degrees Fahrenheit (460 degrees Celsius). Added to the force of the solar wind streaming in from the Sun, scientists have long believed that Venus, very much considered at one time to be a twin of Earth, had lost most of its water (even that thick atmosphere has from 10,000 to 100,000 times less water than Earth’s) through a combination of solar winds from the Sun stripping water-combinant atoms from the atmosphere, the process of the electric field depleting some of the components, and the overall greenhouse effect. Now, however, research indicates that the “electric wind” is far more powerful than originally thought, making it more involved in the depletion of water on Venus.
Glyn Collinson, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, noted that the results of the research could point a redefining of the exoplanet habitability in the search for Earth-like worlds orbiting other stars. He said:
“It’s amazing, shocking. 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 further explained that the “electric wind” wasn’t a simple piece of the overall water-depletion process, but in actuality was the “big monster that’s capable of sucking the water from Venus by itself.”
In the data gathered by the ESA’s Venus Express mission, it was found that in the upper atmosphere of Venus, the hydrogen and oxygen ions were not being stripped from the atmosphere at the same rate as occurs on Earth. They were moving out and escaping Venus’ gravity at five times the speed as hydrogen detected escaping Earth. The electric field, it was determined, was aiding in accelerating the escape of hydrogen due to its greater strength. Thus was the water-depletion process sped up, and, given its closer proximity to the Sun and its streaming solarwinds, allowed for the stripping of necessary components essential to the formation of water. Collinson described oxygen ions on Venus as an “unfortunate” winners of a “terrible, terrible lottery,” where said ions and their “ion friends will be dragged off kicking and screaming into space by an invisible hand, and nothing can save you.”
Venus’ electric field was discovered using an electron spectrometer on the ESA’s Venus Express. It is still unknown just how strong the field might actually be, but then the limits of the strength of Earth’s electric field has yet to be determined as well. Scientists having a working theory that Venus’ closeness to the Sun and its being bombarded with heavier doses of ultraviolet light could be major contributing factors to the electric field’s (and, by extension, the electric wind’s) strength.
Andrew Coates, head of the electron spectrometer team at University College London in the U.K., said that studies are being conducted monitoring the escape of electrons from the atmosphere’s of not just Venus, but also Mars and the Saturnian moon Titan. (In fact, last year, data from the Cassini probe revealed hydrocarbon leakage from Titan’s upper atmosphere around its polar regions, a process similar to Earth’s.) “The new result here,” he said, “shows that the electric field powering this escape is surprisingly strong at Venus compared to the other objects. This will help us understand how this universal process works.”
This information will, as Collinson has noted, be used to further enhance the parameters by which astronomers search for habitable exoplanets. The electric wind data will help to better outline both the size and locations of habitable zones around distant stars. Given that the search for alien life as we know it is dependent upon the availability of water, the existence of higher doses of ultraviolet light or detecting a strong electric wind could help in determining whether or not a certain exoplanet might be habitable or not.
Alex Glocer of NASA Goddard, a co-author on the paper, which was published in the journal Geophysical Research Letters, said of the study’s use with regard to the search for habitable alien worlds, “Even a weak electric wind could still play a role in water and atmospheric loss at any planet. It could act like a conveyor belt, moving ions higher in the ionosphere where other effects from the solar wind could carry them away.”
[Image by Shutterstock]