Jakarta, Beritasatu.com – NASA’s Perseverance mission continues to reveal new details about the history of Mars.
Since landing in Jezero Crater in 2021, the rover has focused on searching for evidence of ancient life by examining the remnants of a long-dried lake. This ongoing exploration highlights the potential for uncovering clues about the Red Planet’s past habitability.
For several years, scientists have been particularly interested in the Western Delta, a geological formation resembling a fan, believed to have formed from river flows billions of years ago.
Now, the latest findings from NASA’s Perseverance rover suggest the possibility of an older, hidden delta lying far beneath the Martian surface. This discovery, based on data from Perseverance’s ground-penetrating radar instrument called RIMFAX, opens new avenues in the search for signs of past life.
Peering Beneath the Surface of Mars with Perseverance
According to reports, the RIMFAX instrument works by continuously emitting radar waves into the Martian soil. As the rover moves approximately 10 centimeters, these waves bounce off different layers of rock, ice, or sediment.
These reflections are then analyzed to create a two-dimensional image of the subsurface structure, similar to ultrasound or sonar technology used on Earth. This method allows scientists to visualize layers that are not directly visible from the surface.
Between September 2023 and February 2024 – a period of roughly 250 Martian days (sols) – Perseverance traversed an area known as the Margin Unit. This region is located between the Western Delta and the crater rim and is rich in carbonate minerals.
Carbonates are of particular interest since, on Earth, these minerals are known to be excellent at preserving traces of life, including microbial fossils. This is why Jezero Crater was initially selected as Perseverance’s landing site.
A Hidden Delta That Could Rewrite Martian History
Analysis of the RIMFAX data, led by astrobiologist Emily L Cardarelli at the University of California Los Angeles, revealed a surprising finding. The rock layers beneath the Margin Unit are highly transparent to radar, allowing signals to penetrate more than 35 meters into the ground.
Accounting for the topography, the total thickness of these layers is estimated to reach 85 to 90 meters. Within this depth, scientists discovered a complex geological structure resembling a river delta.
These layers exhibit sloping and parallel patterns known as clinoforms, a characteristic feature of sediment deposits from flowing water entering a lake. The structure indicates a gradual depositional process, with heavier sediments settling at the top (topset), forming sloping layers (foreset), and eventually spreading into fine layers at the lake bottom.
The presence of these patterns provides strong evidence that the area once experienced dynamic water activity over an extended period.
Timeline of Key Perseverance Discoveries on Mars
Since 2021, Perseverance has recorded several important findings that strengthen the theory that Mars once had an environment capable of supporting life. Shortly after landing, Perseverance sent high-resolution images of a cliff named Kodiak.
Analysis showed that the layered rock structure was a river delta formed approximately 3.7 billion years ago. This discovery provided strong evidence that Jezero Crater was once a lake fed by rivers.
The following year, Perseverance began exploring the delta floor. Here, it found fine-grained sedimentary rocks containing organic material. This suggests that rivers carried material from a wide area outside the crater and slowly deposited it in the calm lake bottom.
In the area dubbed Skrinkle Haven, Perseverance discovered large boulders and coarse gravel arranged in curved patterns in 2023. This structure indicates that Mars not only had calm water flows but as well rivers with strong currents capable of moving large rocks, similar to major rivers on Earth.
While exploring the Margin Unit, the rover found evidence of large floods that occurred periodically. The rocks in this area show that water once flowed in large volumes over short periods, indicating that the ancient Martian climate was not always stable.
In the latest phase of its mission, from 2025 to early 2026, Perseverance reached the crater rim. Here, it discovered carbonate deposits that typically form in aquatic environments such as shorelines.
This discovery is significant because it shows that the interaction between water and the Martian atmosphere lasted long enough to support processes that could preserve traces of microbial life.
Is This Proof of Life on Mars?
Although this discovery of a hidden delta is promising, scientists remain cautious about drawing conclusions. Besides the river delta hypothesis, other possibilities could explain the subsurface structure.
One possibility is volcanic activity, where the observed layers could originate from ash and material from volcanic eruptions. Another hypothesis suggests the layers may be remnants of a shoreline of an ancient lake or the result of glacial activity that carried and deposited large amounts of material.
However, according to Cardarelli, the complexity and scale of the structure found are more consistent with fluvial processes, or flowing water. If true, this would be strong evidence that Mars once had a stable and long-lasting water system, a condition crucial for the potential emergence of microbial life.
The data analyzed currently covers a path of about 6.1 kilometers of Perseverance’s total journey of tens of kilometers. Much data remains unpublished, including observations from the approximately 40 kilometers the rover has traveled.
This means the discovery of the hidden delta may be just the beginning of a series of major findings in Jezero Crater on Mars.
