Martian treasure trove! NASA’s Curiosity Rover finds “strange, unexpected” crystals on Mars
Left: Yellow sulfur crystals discovered after NASA’s Curiosity rover (right) drove over and broke open a rock.
In the barren landscape of Mars, NASA’s intrepid explorer Curiosity has stumbled upon a series of unexpected discoveries that are redefining our understanding of the Red Planet’s geologic history. From pure sulfur crystals to evidence of massive floods, these finds paint a picture of a Mars that was once far more dynamic and water-rich than previously thought.
On May 30, 2024, Curiosity made a groundbreaking discovery as it rolled across the Martian terrain. As its wheels crushed what appeared to be an ordinary rock, scientists on Earth were stunned to see something entirely new glistening on the fractured surface: bright yellow sulfur crystals. This is the first time pure, elemental sulfur has been found on Mars, a discovery that left researchers both excited and “stunned.”
“Finding a field of rocks made of pure sulfur is like finding an oasis in the desert,” said Dr. Ashwin Vasavada, Curiosity’s project scientist at NASA’s Jet Propulsion Laboratory, in a statement. “It shouldn’t be there, so now we have to explain it. Discovering strange and unexpected things is what makes planetary exploration so exciting.”
What is elemental sulfur?
Elemental sulfur is sulfur in its pure form, not combined with other elements. While most people associate sulfur with the smell of rotten eggs, that smell actually comes from hydrogen sulfide gas. Pure sulfur is odorless and usually forms under very specific conditions, which makes its presence on Mars particularly intriguing to scientists.
This sulfurous surprise is just one of several discoveries Curiosity made while exploring the Gediz Vallis Channel, a winding gully in the side of Mount Sharp. This 3-mile-high mountain has been the rover’s stomping ground since 2014, with each layer of rock representing a different chapter in Mars’ history.
The channel itself, discovered from orbit years before Curiosity’s launch, was one of the main reasons scientists sent the rover to this particular region. They believed it might hold clues to Mars’ watery past, and Curiosity’s recent findings have not disappointed them.
As the rover traveled along the channel, it encountered large piles of debris rising from the ground. At first, scientists weren’t sure if these formations were the result of past flooding or landslides, but Curiosity’s close-up investigations have revealed that both processes likely played a role in creating this dramatic landscape.
Some of the debris piles contain rounded stones similar to those found in Earth’s riverbeds, suggesting they were carried and shaped by flowing water. Others are filled with more angular stones, suggesting dry avalanches were their source. This mix of water-worn and freshly broken stones paints a picture of a dynamic, changing Mars.
“This was not a quiet time on Mars,” explains Becky Williams, a scientist at the Planetary Science Institute and deputy principal investigator for Curiosity’s Mastcam. “There was exciting activity here. We’re observing several currents along the channel, including high-energy tides and rock-rich currents.”
Further evidence of water’s influence is the white “halo” that has been bleached into some of the rocks. These markings, reminiscent of those found on Earth when groundwater seeps into fractured rock, suggest that water continued to play a role in shaping the landscape long after the floods and avalanches had subsided.
To better understand this complex geological history, the Curiosity team set out to collect a rock sample from the channel. On June 18, they successfully attempted to drill into a large rock nicknamed “Mammoth Lakes.” This was the rover’s 41st drilling operation on Mars.
The pulverized rock sample was carefully placed into instruments inside Curiosity’s body for detailed analysis. Scientists hope this sample will provide important information about the materials that make up the channel and provide further insight into Mars’ past.
These recent discoveries continue to challenge and expand our understanding of Mars’ history. In particular, the presence of pure sulfur crystals raises exciting questions about the chemical processes that once took place on the planet’s surface. Sulfur, a key element in many biological processes on Earth, could potentially provide clues to the habitability of ancient Mars.
As Curiosity continues its journey through the Gediz-Vallis Channel, scientists eagerly await what other surprises lie ahead. Each new discovery brings us closer to unlocking the secrets of Mars’ past and understanding the potential for life beyond Earth.
The Curiosity mission, managed by NASA’s Jet Propulsion Laboratory under the Science Mission Directorate, has been exploring Mars since it landed in 2012. Its main goal is to study the planet’s geology and climate, and to determine whether Mars could have ever hosted microbial life. Discoveries like these sulfur crystals and evidence of ancient flooding not only contribute to that goal, but also pave the way for future exploration of the Red Planet.
