Venus is our toxic twin. Its chemical composition, size and density are similar to those of our world, although its hellish temperatures can melt lead and its atmosphere is full of sulfuric acid.
But it may be even more Earth-like than we knew. A paper published last week in Science Advances demonstrates that Venus could still harbor active volcanoes. If confirmed, the discovery could help astronomers and planetary scientists in their search for life on other worlds.
Scientists have long wondered if Venus might be volcanically active. In the early 1990s, cloud-penetrating radar on the Magellan orbiter revealed a surface studded with volcano-like mountains. But no one knew if these features remained active. Then, in 2010, data from the European spacecraft Venus Express revealed several hotspots suggesting that lava had flowed just 250,000 years ago. And in 2012, the orbiter observed spikes of sulfur dioxide — a gas that smells like a match and is commonly produced on Earth by active volcanoes — in the Venusian atmosphere.
The evidence was enticing, but incomplete. “The data currently available for Venus cannot provide unequivocal compelling evidence,” said Tracy Gregg, a geologist at the University at Buffalo.
So Justin Filiberto, a planetary scientist at the Lunar and Planetary Institute in Houston, decided to take another look. His team experimented with crystals of olivine, a green mineral commonly found in volcanic rock. Specifically, they wanted to see how the mineral might change once it erupts in Venus’ hot atmosphere.
To find out, the researchers heated the olivine to around 1,600 degrees Fahrenheit and exposed it to oxygen, which is also found on Venus. Under these extreme conditions, the outer grains of olivine turned into iron oxide, and very quickly. Because olivine is rapidly disappearing, finding evidence of the mineral on the surface of Venus would mean young lava flows.
Dr. Filiberto and his colleagues therefore turned to archived data from the Venus Express orbiter. They discovered that lava flows dating back 250,000 years actually contained olivine, proof that they were only a few years old.
“This means that Venus looks a lot more like Earth than we thought,” said Dr Filiberto.
Some scientists have deemed this new timeline remarkable.
“What we’re talking about now is decent evidence that these things are not just geologically young, but young on a human scale,” said Noam Izenberg, a planetary geologist at Johns Hopkins University who was not involved in the survey. the study.
But Dr Gregg, who hailed the research as a “great example of scientific method”, worried the team had not looked at the precise chemical composition of Venus’ atmosphere, including sulfur, which could affect the reaction. chemical. She also noted that scientists aren’t quite sure what the atmosphere looks like on the surface of Venus, as the closest measurement was taken miles above the ground.
To confirm the results, scientists will have to send a probe to Venus – an argument that is starting to sound like a broken record. The last spacecraft with the primary mission of mapping the planet’s topography was NASA’s Magellan orbiter, launched more than 30 years ago. Since then, two missions have been sent to study our brother, but with the main purpose of analyzing the atmosphere of Venus.
But if scientists could go back to our toxic twin and prove that volcanoes are active today, they might even help test a hypothesis that Venus is biologically alive today.
In 2018, scientists postulated that changing patterns in the planet’s atmosphere could be explained by microbial life. And the idea isn’t far-fetched: the upper atmosphere is actually quite pleasant, with cool temperatures and low pressures. But how would you bring nutrients into the Venusian atmosphere to help sustain these microbes?
Volcanoes, of course.
“Heat is energy, chemicals are food, so you’re basically providing nutrients and a good way of life,” Dr Gregg said. “It’s really hard to imagine life, in any form, in the absence of volcanic activity.”