Venus Could Have Active Volcanoes

Venus Could Have Active Volcanoes
<em>Volcanic peak Idunn Mons, created using data from Venus Express.</em> (Image: NASA)

Laboratory experiments have uncovered evidence that Venus might still be volcanically active.

Earth is the only planet with known active volcanoes (though Jupiter’s moon Io is quite volcanically active). As for Venus, a spacecraft called the Venus Express orbited the planet from 2006 to 2014 and took data, but directly observing volcanic activity on the surface is difficult because of its thick atmosphere. A new lab experiment demonstrated that one of that spacecraft’s observations could be explained by days-old volcanic activity altering rocks called olivine.

Scientists previously found evidence of volcanoes and lava flows on Venus’s surface, but they couldn’t figure out the age of these flows. Generally, scientists study the composition of a planet’s surface based on the different wavelengths of light that it emits and reflects. But in the case of Venus, they have fewer emission lines to work with due to the atmosphere’s carbon dioxide absorbing some of the light. Fully characterising the minerals on Venus’s surface requires computer simulations as well as understanding how chemical reactions, like the gassy atmosphere interacting with surface minerals after an eruption, can affect the signals that Venus Express observed.

A previously published study by the same authors measured the properties of olivine, a mineral thought to exist on Venus’s surface, including the amount and wavelengths of light it reflected after it was oxidized in a blast furnace at 600 and 900 degrees Celsius. After a month of oxidation, the olivine developed a rusty coat of hematite, changing the wavelengths of light it reflected.

This is important because Venus Express results seemed to record the signature of olivine, according to the paper published last week in Science Advances. But if olivine quickly oxidizes under the hot Venusian atmosphere, then the olivine that Venus Express observed might be only a few months old. Volcanoes might have brought olivine to the surface of the planet just days before the Venus Express observations. This evidence, combined with occasional spikes in atmospheric sulphur dioxide that both Venus Express and the Pioneer Venus Orbiter recorded, makes a stronger case for present-day volcanism on Venus.

This research isn’t direct evidence of volcanism on the planet’s surface, of course. But it’s motivation for another mission to our understudied neighbour, which might be able to answer that question for sure—though only if our technology can handle the planet’s terrifying atmosphere.