Mars rover reveals a watery and possibly life-supporting past

Since its touchdown in Jezero Crater in February 2021, NASA’s Perseverance rover has steadily explored Martian rocks. From ancient volcanic deposits to layers formed by vanished lakes and river deltas, the rover's journey helps scientists piece together Mars’ hidden past.

Among the most exciting discoveries are minerals known as sulfates, found abundantly in fractures within Martian rock. These minerals hold essential clues to the planet's ancient environment and, possibly, past life.

NASA chose Jezero Crater specifically because it once held water, creating ideal conditions for life. Within Jezero lies the Shenandoah formation, a sedimentary area on the crater’s western edge, full of fine-grained rocks cemented by sulfate minerals. Understanding exactly how these sulfates formed—and when—could answer whether life ever existed on Mars.

Sulfates form when water evaporates, leaving behind minerals rich in sulfur and calcium. These minerals exist widely on Mars, making up 4% to 8% of Martian soil. They're also embedded in the planet's layered sediments and cemented within sandstones and siltstones. Past rover missions, including Opportunity and Curiosity, found similar sulfate veins. Such discoveries suggest water once flowed beneath Mars' surface.

On Earth, sulfate minerals can preserve microscopic fossils of microbes. Finding similar structures on Mars could indicate past life. Yet, to interpret these potential signs accurately, scientists must first understand the minerals' origins.

Dr. Michael Jones, a scientist from the Queensland University of Technology (QUT), emphasized their importance: “Sulphate minerals exist with different amounts of water in most regions on Mars and allow us to understand how water moved around the planet, which is key to understanding its past habitability.”

To investigate these minerals, the Perseverance rover studied two locations within the Shenandoah formation: Hogwallow Flats and Yori Pass. At these sites, rover instruments discovered significant sulfate deposits. Researchers found sulfate minerals not just scattered through the rock but concentrated in distinct veins and cavities.

Previously, it was unclear whether these veins formed at or near the surface, or deeper underground. The answer would dramatically change our understanding of Mars' watery past. To solve this puzzle, scientists developed a groundbreaking technique called X-ray Backscatter Diffraction Mapping (XBDM). This method, created by Dr. Jones and Professor Christoph Schrank at the Australian Synchrotron, was adapted for Perseverance’s onboard instruments.

XBDM maps the internal structure of minerals by bouncing X-rays off their crystals. Unlike traditional methods, it doesn't require samples to be polished or coated, making it perfect for Mars' challenging environment. Perseverance's instrument called PIXL used this method to analyze sulfate minerals in place, a task previously considered impossible on Mars.

"Our team found a way to measure the internal crystal structure of these minerals directly in the rock," Dr. Jones explained, marking a significant leap in planetary geology.

Using XBDM, scientists discovered not one but two generations of sulfate minerals in the Shenandoah formation. Each generation formed under different conditions and at different depths, revealing a complex geological past.

The first generation of sulfates crystallized just below Mars’ ancient surface. These shallow minerals suggest water was once abundant and evaporated quickly, creating ideal conditions for life at the surface. The second generation formed much deeper, at least 80 meters below ground, under higher pressure and stable chemical conditions.

These findings highlight multiple periods when Mars could have hosted life. “This discovery highlights the diversity of environments that existed in the Shenandoah formation’s history—indicating multiple potential windows when life might have been possible on Mars,” Dr. Jones said.

Understanding the timing and depth of sulfate formation is critical. Minerals formed near the surface point to environments more likely exposed to sunlight and oxygen—conditions favorable for microbial life. Deeply formed sulfates suggest water persisted underground, offering stable habitats protected from harsh surface conditions.

The variety of sulfate minerals also gives scientists clues about the ancient climate. For instance, anhydrite, a sulfate without water, was common at the sites studied. Instruments like SHERLOC and SuperCam detected this mineral clearly. The presence of anhydrite implies dry conditions following wetter periods, marking significant shifts in Mars’ climate.

To further unravel Mars’ mysteries, Perseverance collected rock cores containing sulfates from the Shenandoah formation. At Hogwallow Flats, the rover gathered cores named "Hazeltop" and "Bearwallow." At Yori Pass, the core "Kukaklek" was retrieved. These samples are now stored securely on Mars, waiting for a future mission that could bring them to Earth.

Studying these samples directly on Earth would give scientists unprecedented details about Mars' environment. Such analyses could reveal organic molecules or even microfossils preserved within the sulfate veins, confirming once and for all if Mars ever supported life.

Associate Professor David Flannery, a long-term planner for NASA’s Mars missions, underscored the significance of these findings: “Experience gained by QUT researchers exposed to the cutting edge of robotics, automation, data science, and astrobiology fields has the potential to kick start Australia’s space industry.”

Every new discovery by Perseverance pushes science closer to answering if life existed beyond Earth. The rover's sulfate mineral findings are among the most significant yet, proving Mars had multiple environments suitable for life at different depths and times.

This knowledge doesn't just teach us about Mars. It helps scientists better understand the universal conditions required for life, guiding future explorations of other worlds.

Today, teams like the QUT Planetary Surface Exploration Research Group continue exploring Mars through Perseverance. Their work, integrating robotics, chemistry, and planetary geology, positions them at the forefront of space research.

As Perseverance continues exploring Jezero crater, each rock studied and sample collected adds a piece to Mars’ complex puzzle. Someday soon, these clues could finally answer humanity's greatest question: are we alone in the universe?

Note: The article above provided above by The Brighter Side of News.

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