Mars was once a "planet of rivers" that could have easily harbored life

In a new study that transforms our understanding of the Martian landscape, researchers led by Benjamin Cardenas, assistant professor of geosciences at Penn State, have unveiled evidence suggesting that the red planet was once abundant with rivers. The research team paints a picture of a Martian past that could have harbored life.

Mars: A planet of rivers

The study indicates that numerous craters on Mars, previously overlooked in this context, may have once been active riverbeds.

“We’re finding evidence that Mars was likely a planet of rivers,” Cardenas explains, alluding to the widespread signs across the Martian surface pointing towards an aqueously abundant past.

This revelation challenges the long-standing perceptions of Mars as a largely dry and barren landscape, reinvigorating the scientific community’s pursuit to uncover the planet’s enigmatic past.

Peering into the Martian past

The cornerstone of this pioneering study is the innovative use of numerical models to simulate the erosion patterns on Mars. The research team delved into the erosion processes that have shaped the Martian surface over millennia. They discovered that the commonly found crater formations, known as bench-and-nose landforms, are likely the remnants of ancient riverbeds.

This technique marked the first instance of using a combination of satellite data, Curiosity rover images, and 3D scans of stratigraphy (rock layers deposited over millions of years) beneath the Gulf of Mexico seafloor. Combined, these data sources offer a comprehensive view of Martian geological history.

Through this intricate analysis, the team unearthed a new interpretation for these Martian crater formations, associating them with eroded river deposits.

Cardenas highlights the significance of this stratigraphic interpretation, stating, “This analysis is not a snapshot, but a record of change. What we see on Mars today is the remnants of an active geologic history, not some landscape frozen in time.”

Fluvial ridges and Mars river deposits

Previous Martian studies identified certain erosional landforms, known as fluvial ridges, as potential candidates for ancient river deposits. However, this new study broadens the scope of investigation. The team recognized signs of river deposits in bench-and-nose landforms that have never before been connected to ancient rivers.

Cardenas enthuses, “This suggests that there could be undiscovered river deposits elsewhere on the planet, and that an even larger section of the Martian sedimentary record could have been built by rivers during a habitable period of Mars history.”

Reflecting on the implications for life, he adds, “On Earth, river corridors are so important for life, chemical cycles, nutrient cycles, and sediment cycles. Everything is pointing to these rivers behaving similarly on Mars.”

Earth’s stratigraphy sheds light on Mars

In a creative twist, the research team repurposed 25-year-old scans of Earth’s stratigraphy from beneath the Gulf of Mexico, collected by oil companies, for their Martian studies. These scans, Cardenas notes, provided an “ideal comparison to Mars,” aiding in the simulation of Mars-like erosion.

The team’s simulations revealed Martian landscapes shaped into topographic benches and noses, mirroring the landforms observed by the Curiosity rover inside Gale crater, rather than the fluvial ridges previously associated with such features.

Hopeful horizon: Ancient life on Mars

This study does more than reconstruct the ancient Martian environment. It also ignites new hope for uncovering signs of past life on the red planet.

“Our research indicates that Mars could have had far more rivers than previously believed, which certainly paints a more optimistic view of ancient life on Mars,” asserts Cardenas.

The discovery, suggesting that most of the Martian landscape once possessed the right conditions for life, marks a monumental stride in planetary science, reshaping our understanding of our celestial neighbor.

The research, co-authored with Kaitlyn Stacey, a doctoral candidate in planetary geosciences at Penn State, received funding from a NASA Solar System Workings Grant, underscoring its significance in the continued exploration of our solar system.

The full study was published in the journal Geophysical Research Letters.

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