Venus is one of the most inhospitable environments in our solar system, with surface temperatures hot enough to melt lead and atmospheric pressure nearly 100 times greater than Earth’s. Yet its surface may preserve clues to a time when the planet looked much more like Earth.
Scientists are investigating whether Venus was once much wetter and potentially even had water on its surface.
Sara Taeko Port, a postdoctoral researcher in the UT San Antonio Department of Physics and Astronomy, is collaborating with NASA and Arizona
State University (ASU) to investigate whether minerals on Venus could preserve evidence of that wetter past and provide new insights into the planet’s volcanic activity.
“One of the exciting things we identified is that Venus’ extreme atmosphere doesn’t necessarily erase all evidence of its past,” Port said. “Fluorine in the atmosphere can help stabilize minerals that may have originally formed when water was more abundant. If we find these fluorine-bearing minerals on Venus, they could give us clues about Venus’ past surficial water.”
The research was funded by NASA’s Glenn Research Center.
Simulating one of the solar system’s harshest environments
For the last decade, Port has been investigating how minerals react under Venus-like conditions.
Her latest research exposed six rock-forming minerals to conditions closely simulating the surface of Venus for 60 consecutive days in an atmosphere including nine gasses.
The experiments were conducted using the Glenn Extreme Environment Rig (GEER), the most comprehensive Venus simulation chamber in the world, located at NASA Glenn Research Center. The 811-liter chamber recreates Venus’ intense heat, pressure and atmospheric chemistry. Researchers then used advanced analytical instruments at ASU to examine how the minerals responded to this extreme environment.
The results showed that Venus’ atmosphere can dramatically alter surface minerals, but some of those transformations may preserve evidence of the planet’s past.
Hydrogen fluoride in the atmosphere reacted with water-bearing minerals, transforming them into fluorine-bearing micas that remain stable under Venus’ extreme surface conditions. If future spacecraft detect these minerals on Venus, their presence could provide evidence that water-bearing minerals existed earlier in the planet’s history.
Researchers also observed the formation of magnesite, a magnesium carbonate, through interactions between the water-rich mineral brucite and carbon dioxide. The finding provides another potential mineralogical clue to Venus’ ancient water and carbon dioxide cycles.
Evidence of a volcanically active Venus
The experiments also offered insight into Venus’ present-day conditions. Sulfur-bearing minerals formed on nearly all of the samples, demonstrating how strongly the atmosphere’s sulfur dioxide reacts with fresh surface material. Those reactions would continuously strip sulfur dioxide and hydrogen fluoride out of the atmosphere.
Maintaining the gases at their observed atmospheric levels suggests a continuing source of replenishment, potentially including volcanic degassing and the exposure of fresh volcanic material at the surface.
Preparing for future missions to Venus
The findings come as NASA and the European Space Agency prepare several missions to Venus, including NASA’s DAVINCI and VERITAS missions and ESA’s EnVision mission. The minerals identified in Port’s research could give scientists specific targets to look for and help them interpret what those missions discover.
Understanding rocky planets beyond our solar system
Maitrayee Bose, associate professor in the School of Earth and Space Exploration at ASU, has collaborated with Port for several years. The two coauthored a recent study, “New Insights into Venus’s Volatile Cycles Revealed by the Formation of Magnesite and Fluoro–Micas,” published in the Planetary Science Journal. Their work examining Venus-like conditions could also help scientists better understand rocky planets beyond our solar system.
“Venus and Earth likely started with many of the same basic ingredients, yet today they are dramatically different planets,” Bose said. “Understanding how Venus’ surface and atmosphere have interacted over geologic time can help us reconstruct how Venus evolved, why it became so different from Earth, and what that tells us about the evolution of rocky planets beyond our solar system.”
