Volcanic sulfur gases may have warmed ancient Mars enough to support life, new study suggests
By isabelle // 2025-09-12
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  • New research suggests ancient Martian volcanoes released sulfur gases that warmed the planet enough for liquid water and possible microbial life.
  • NASA’s Curiosity rover recently discovered pure sulfur on Mars, supporting the study’s claim that volcanic activity created life-friendly conditions.
  • Computer models show reduced sulfur compounds like hydrogen sulfide and sulfur hexafluoride may have formed a heat-trapping atmosphere.
  • Martian meteorites contain reduced sulfur, hinting at a past where volcanic eruptions shaped a warmer, wetter climate.
  • The findings challenge old assumptions and suggest Mars may have once hosted ecosystems similar to Earth’s early hydrothermal life.
For decades, scientists have debated whether Mars was ever warm enough to host liquid water... and possibly life. Now, a groundbreaking study from the University of Texas at Austin suggests that volcanic eruptions billions of years ago may have released sulfur gases that created a greenhouse effect, making the Red Planet far more hospitable than previously believed. The research, published in Science Advances, challenges previous assumptions about Mars’ early atmosphere. Instead of sulfur dioxide (SO₂) dominating volcanic emissions, the team’s computer simulations indicate that reduced sulfur compounds such as hydrogen sulfide (H₂S) and sulfur hexafluoride (SF₆) were likely far more abundant. These gases, particularly SF₆, are extremely potent at trapping heat, potentially raising temperatures enough to allow liquid water to persist.

A warmer, wetter Mars?

Lead author Lucia Bellino, a doctoral student at UT’s Jackson School of Geosciences, explained that these reactive sulfur gases could have formed a hazy atmosphere, much like Earth’s early volcanic environments. "The presence of reduced sulfur may have induced a hazy environment which led to the formation of greenhouse gases, such as SF₆, that trap heat and liquid water," Bellino said. She noted that similar conditions on Earth support microbial life in hydrothermal systems, raising the possibility that Mars once had comparable ecosystems. The study’s findings align with a surprising discovery made by NASA’s Curiosity rover in May 2024, when it crushed a rock and exposed pure elemental sulfur—a first for Martian exploration. "We were very excited to see the news from NASA and a large outcrop of elemental sulfur," said Chenguang Sun, Bellino’s advisor. "One of the key takeaways from our research is that as S₂ was emitted, it would precipitate as elemental sulfur. When we started working on this project, there were no such known observations."

Volcanic activity as a life-supporting mechanism

The researchers used data from Martian meteorites and ran more than 40 simulations to model how sulfur cycled through Mars’ crust and atmosphere. Their work suggests that sulfur frequently shifted between different chemical states, which could have created dynamic environmental conditions. While the Martian surface today is rich in oxidized sulfur (bound to oxygen), the meteorites contain reduced sulfur, hinting at a past where volcanic activity played a key role in shaping the planet’s climate. This isn’t the first time scientists have proposed that Mars’ volcanic history could have supported life. A separate study led by Texas A&M researcher Michael Tice analyzed rocks in Jezero Crater, where NASA’s Perseverance rover is currently exploring. Tice’s team found mineral-rich volcanic rocks that suggest prolonged volcanic activity, which "could have provided a sustained source for different compounds used by life."

What are the implications for future exploration?

The UT Austin team plans to expand their research to investigate how volcanic activity might have contributed to water sources on early Mars. They also hope climate modelers will use their findings to estimate just how warm the planet’s ancient atmosphere could have been and whether microbial life might have thrived there. For now, the study adds compelling weight to the idea that Mars was once a far more dynamic world—one where volcanoes didn’t just reshape the landscape, but may have also set the stage for life.

A reminder of Earth’s own volcanic origins

This research underscores a critical truth: the conditions that make a planet habitable are often far more complex than we assume. Just as Earth’s early atmosphere was shaped by volcanic activity, Mars may have followed a similar path. The difference? On Earth, life took hold. On Mars, the window may have closed too soon. But if these findings hold, they could rewrite our understanding of where and how life might exist beyond our planet. Sources for this article include: Phys.org Space.com LiveScience.com
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