Venus is our toxic twin. Its chemical makeup, size and density is similar to our world’s, although its hellish temperatures can melt lead, and its atmosphere is rife with sulfuric acid.
But it may be even more Earthlike than we knew. A paper published last week in Science Advances demonstrates that Venus might still harbor active volcanoes. If confirmed, the finding could help astronomers and planetary scientists as they search for life on other worlds.
Scientists have long debated whether 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 whether these features remained active. Then in 2010, data from Europe’s Venus Express spacecraft revealed several hot spots that suggested lava had flowed as recently as 250,000 years ago. And in 2012, the orbiter observed spikes in sulfur dioxide — a gas that smells like a struck match and is commonly produced on Earth by active volcanoes — within the Venusian atmosphere.
The evidence was tantalizing, but incomplete. “The data that are currently available for Venus cannot unequivocally provide the smoking gun,” 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 erupted into the hot, Venusian atmosphere.
To find out, the researchers heated olivine up to roughly 1,600 degrees Fahrenheit and exposed it to oxygen, which can also be found on Venus. Under such extreme conditions, the outer grains of olivine transformed into iron oxide, and very rapidly. Because olivine disappears quickly, the discovery of evidence of the mineral on the surface of Venus would signify young lava flows.
So Dr. Filiberto and his colleagues turned toward archived data from the Venus Express orbiter. They found that the lava flows previously dated at 250,000 years old actually contained olivine — proof that they were only a few years old.
“It means that Venus is a lot more like Earth than we thought,” Dr. Filiberto said.
Some scientists considered this new timeline remarkable.
“What we’re talking about now is some decent evidence that these things are not just geologically young, but young on the human scale,” said Noam Izenberg, a planetary geologist at Johns Hopkins University who was not involved in the study.
But Dr. Gregg, who praised the research as a “great example of the scientific method,” worried that the team did not look at the precise chemical makeup of the Venusian atmosphere, including sulfur, which might affect the chemical reaction. She also noted that scientists don’t actually know what the atmosphere looks like on Venus’s surface because the closest measurement was taken miles above the ground.
To confirm the findings, scientists will have to send a probe to Venus — an argument that is beginning to sound like a broken record. The last spacecraft with a primary mission of mapping the planet’s topography was NASA’s Magellan orbiter, which launched more than 30 years ago. Since then, two missions have been sent to study our sibling, but with the primary purpose of analyzing Venus’s atmosphere.
But if scientists could return to our toxic twin and prove that volcanoes are active today, they might even help test out a hypothesis that Venus is alive today, biologically speaking.
In 2018, scientists postulated that evolving patterns in the planet’s atmosphere could be explained by microbial life. And the idea isn’t too far-fetched: The high atmosphere is actually quite pleasant, with cool temperatures and low pressures. But how would you deliver nutrients into the Venusian atmosphere to help sustain those microbes?
Volcanoes, of course.
“Heat is energy, chemicals are food, so you’re basically bringing up nutrients and a good lifestyle,” Dr. Gregg said. “It’s really hard to imagine life, of any form, in the absence of volcanic activity.”