A monument to a lost era, carved by forces that no longer operate
Three and a half billion years ago, catastrophic floods burst from beneath the Martian surface and carved a wound into the planet that time has never fully healed. New imagery from the European Space Agency's Mars Express spacecraft has brought Shalbatana Vallis — a 1,300-kilometer channel etched into the Martian equatorial region — into sharper focus than ever before, revealing a landscape that speaks of a world once warm, wet, and violently alive. The valley, pointing like an accusation toward the lowland plains of Chryse Planitia, lends weight to the theory that Mars once harbored a vast ocean, and quietly deepens the oldest question we ask of other worlds: could life have found a foothold there?
- Groundwater trapped under immense pressure erupted through the Martian crust 3.5 billion years ago, carving a channel 10 kilometers wide and 500 meters deep across a landscape that still bears the scar.
- Mars Express's High Resolution Stereo Camera has returned the clearest images yet of Shalbatana Vallis, forcing scientists to reckon with the full complexity of a terrain shaped by floods, volcanic ash, collapsing ice, and ancient lava flows.
- The valley sits at a planetary crossroads — the boundary between Mars's cratered southern highlands and its smoother northern lowlands — and its waters appear to have drained toward Chryse Planitia, a region many researchers believe once held a vast ocean.
- Researchers at Freie Universität Berlin and the DLR Institute in Berlin are processing three-dimensional perspective views of the valley, slowly translating geological violence into a coherent narrative of planetary transformation.
- The emerging picture repositions Mars not as a world that was always barren, but as one that lost something — warmth, water, and perhaps the conditions for life — and understanding that loss has become one of planetary science's most urgent pursuits.
Three and a half billion years ago, groundwater trapped beneath the Martian surface burst upward with catastrophic force, carving a channel across the planet that remains visible today. That channel is Shalbatana Vallis — roughly 1,300 kilometers long, about the length of Italy — and the European Space Agency's Mars Express spacecraft has just returned its clearest images of it yet.
The valley is a study in geological violence. Ten kilometers wide and plunging 500 meters deep, it winds from the highlands of Xanthe Terra southward toward the plains of Chryse Planitia, curving across the Martian equator like a river frozen in place. Sediments have partially filled what was once an even more dramatic chasm, but the latest imagery from Mars Express's High Resolution Stereo Camera reveals the northern section in unprecedented detail — not just the main channel, but the fractured, layered terrain surrounding it.
What makes Shalbatana Vallis particularly significant is its place within a larger story. It belongs to a network of outflow channels marking the boundary between Mars's heavily cratered southern highlands and its smoother northern lowlands — and all of them seem to point toward Chryse Planitia, one of the planet's lowest regions. Many scientists believe that water flowing through these channels once accumulated there, forming a vast ancient ocean. If so, Shalbatana Vallis is not merely a geological feature — it is evidence of a lost sea.
The surrounding terrain adds further texture to the narrative. Patches of chaotic collapsed ground suggest that underground ice once melted and caused the surface above to buckle and shift. Dark smears of volcanic ash, redistributed by Martian winds over millions of years, mark the valley's wider sections. Impact craters at various stages of erosion dot the landscape, alongside ancient lava flows and isolated mesa remnants of older surfaces worn gradually away.
The images were processed at the DLR Institute of Space Research in Berlin and analyzed by researchers at Freie Universität Berlin, who constructed three-dimensional perspective views that reveal the valley's true structure. Mars Express, orbiting the planet since 2003, has spent more than two decades building this kind of geological portrait — one that increasingly depicts a Mars that was once warmer, wetter, and far more dynamic than the cold, dry world we observe today. Shalbatana Vallis stands as a monument to that lost era, and understanding how Mars made the journey from potentially habitable to its current state remains one of the defining questions of planetary science.
Three and a half billion years ago, something catastrophic happened beneath the Martian surface. Groundwater, trapped underground under immense pressure, suddenly burst upward and rushed across the landscape with such force that it carved a scar into the planet that remains visible today. That scar is Shalbatana Vallis, a channel stretching roughly 1,300 kilometers across Mars—about the length of Italy—and the European Space Agency's Mars Express spacecraft has just captured its clearest images yet, revealing a landscape that tells the story of a planet far wetter and more dynamic than Mars appears now.
The valley itself is a study in geological violence. Ten kilometers wide and plunging 500 meters deep, Shalbatana Vallis winds from the highlands of Xanthe Terra in the south toward the plains of Chryse Planitia in the north, curving across the Martian equator like a river that froze in place billions of years ago. But the channel is not as deep as it once was. Over eons, sediments and debris have accumulated in its depths, partially filling what was once an even more dramatic chasm. The latest images from Mars Express's High Resolution Stereo Camera show the northern section of the valley in unprecedented detail, revealing not just the main channel but the complex terrain surrounding it—a landscape that scientists are still learning to read.
What makes Shalbatana Vallis particularly significant is what surrounds it. The valley is part of a network of outflow channels that mark a fundamental boundary on Mars: the transition between the heavily cratered southern highlands and the smoother northern lowlands. This is not random geology. The channels all seem to point toward Chryse Planitia, one of the lowest regions on the planet. Many scientists now believe that during Mars's warmer, wetter past, water flowing through these channels accumulated in Chryse Planitia and formed a vast ocean. If that theory is correct, then Shalbatana Vallis is not just a geological feature—it is evidence of a lost sea.
The terrain surrounding the valley tells additional stories. Scattered throughout the region are patches of chaotic terrain, a jumbled landscape of broken blocks, ridges, and rocky mounds that looks as though the ground itself had a violent argument with itself. Scientists believe these formations developed when underground ice melted, causing the surface above to collapse and shift. Dark patches visible in the valley's wider sections appear to be volcanic ash, redistributed by Martian winds over millions of years. Impact craters dot the landscape—some still sharp-edged, others worn down by time, still others partially buried beneath accumulated material. Much of the surrounding terrain shows the wrinkled, folded appearance of ancient lava flows that cooled and contracted over billions of years. Isolated hills called mesas rise from the plains, remnants of older surfaces that have gradually eroded away.
The images come from Mars Express, a spacecraft that has been orbiting Mars since 2003 and has spent more than two decades mapping the planet's surface in color and three dimensions at a level of detail that was unimaginable when the mission launched. The High Resolution Stereo Camera aboard the spacecraft, developed and operated by the German Aerospace Center, has become one of the most important tools for understanding Mars's geological history. The latest images of Shalbatana Vallis were processed at the DLR Institute of Space Research in Berlin and analyzed by researchers at Freie Universität Berlin, who created the three-dimensional perspective views that reveal the valley's true structure.
What emerges from these images is a portrait of a planet that was once fundamentally different from what we see today. The evidence of massive floods, the network of outflow channels, the presence of chaotic terrain and volcanic activity, the suggestion of an ancient ocean in Chryse Planitia—all of it points toward a Mars that was warmer, wetter, and geologically more active than the cold, dry world we observe now. Shalbatana Vallis is a monument to that lost era, carved by forces that no longer operate on the Martian surface. Understanding how and why Mars changed from a potentially habitable world to its current state remains one of the central questions in planetary science, and images like these bring us closer to an answer.
Notable Quotes
Scientists believe Shalbatana Vallis formed around 3.5 billion years ago when massive amounts of groundwater burst upward from beneath Mars's surface, with those powerful floods rapidly eroding the landscape and carving deep channels as the water rushed downhill.— Mars Express research team
The Hearth Conversation Another angle on the story
Why does a valley carved billions of years ago matter to us now?
Because it's evidence that Mars was once fundamentally different. If water flowed through Shalbatana Vallis in such volume that it carved a channel ten kilometers wide and half a kilometer deep, that tells us something about the planet's climate and atmosphere at that time. It wasn't the frozen desert we see today.
You mention a possible ancient ocean in Chryse Planitia. How confident are scientists about that?
It's a working theory, not proven fact. But the geography is suggestive. All these major outflow channels seem to terminate in Chryse Planitia, which is one of the lowest regions on Mars. Water would naturally flow downhill and collect there. Whether it actually formed a persistent ocean is still being debated.
The images show volcanic ash and impact craters alongside the flood channels. Does that mean all this happened at the same time?
Not necessarily. Mars has a long geological history. The floods carved the valley around 3.5 billion years ago, but the volcanic activity and impacts could have occurred at different times. What we're seeing is a palimpsest—multiple geological events layered on top of each other over billions of years.
What does the chaotic terrain tell us?
It's a signature of underground ice melting. When subsurface ice thaws, the ground above loses support and collapses, creating that jumbled, broken landscape. It suggests there was once enough heat and water on Mars to destabilize frozen ground—another sign of a warmer past.
Mars Express has been orbiting for over twenty years. Are we still learning new things from it?
Absolutely. The camera technology has improved, the processing techniques have become more sophisticated, and we keep finding new details in old data. Plus, each new image adds to our understanding of how these geological features relate to each other across the planet.