Top 5 Coolest Things The Curiosity Rover Has Found On Mars

Mars is the only planet populated exclusively by robots. That fact is the rather mind-boggling result of what easily qualifies as humanity's greatest-ever technological achievement — building and launching space-faring machines that can operate 140 million miles from Earth. In August 2012, NASA's Curiosity rover joined that lineage when it touched down in Mars' Gale Crater, a basin created from a meteor impact 3.7 billion years ago. The crater features a mountain at its center, Mount Sharp, just one of the oddities that led to it being chosen as the landing spot for Curiosity.

Originally expected to survive for two years on the surface of the Red Planet, Curiosity is still active and in remarkably good shape. Its durability can be attributed to its stellar engineering and technical capabilities. It's equipped with 10 scientific instruments, including a laser-firing ChemCam that vaporizes materials for spectrographic analysis, a Sample Analysis at Mars (SAM) suite for detecting organic molecules, and a high-resolution camera system for capturing detailed images of the Martian surface.

During Curiosity's decade-plus lifetime, the little rover-that-could has put that instrument suite to incredible use, helping scientists make some insanely cool discoveries about Mars and its history that have transformed our understanding of the planet. Evidence of ancient lakes, organic molecules in Martian rocks, and seasonal shifts in atmospheric methane are just some of its groundbreaking contributions to the scientific record. Here, we take a look at Curiosity's top 5 coolest discoveries and what they mean for the future of humanity's understanding and continued exploration of the Red Planet.

Perhaps the top candidate for Curiosity's most exciting and potentially transformational discoveries came in 2018 when the rover detected complex organic molecules preserved in ancient Martian rock. Using its Sample Analysis at Mars (SAM) instrument suite, Curiosity analyzed mudstone (a kind of sedimentary rock) samples from Gale Crater, revealing the presence of organic compounds like thiophenes and benzene as well as small carbon chains.

These kinds of molecules are the building blocks of life. However, their presence doesn't automatically mean the Red Planet actually harbored any. They could be traces of interactions between the sun's ultraviolet light and carbon dioxide in the Martian atmosphere, which would have produced such organics that then fell to the surface.

Still, the find is nothing short of momentous. If Mars ever harbored life, these organic compounds would be a crucial part of its history. The compounds' discovery is so important that Charles Malespin and Amy Mcadam, SAM's principal and deputy investigators at NASA's Goddard Space Flight Center in Maryland (where Curiosity was designed and built), believe that they are Curiosity's most significant find to date.

In 2023, Curiosity made a stunning discovery in Gale Crater: wave-rippled textures preserved in the Martian rock. The rover happened upon these in an area known as the "Marker Band," a strip of distinctly-colored rock on Mount Sharp, the mountain at the crater's center. The ripples are an indication of ancient water activity from billions of years ago caused by waves moving across the surface of a shallow lake. What makes the finding particularly unique is that these ripples exist in a region scientists expected to be dry.

A January 2025 research paper in Science Advances provided a more detailed analysis of the origin of these ripples. Its authors argue that the small waves that resulted in these patterns occurred in ice-free, open-water conditions around 3.7 billion years ago (if you're curious, you can also learn about the exciting secret Martian ice could be hiding). This means that at some point, Mars' atmosphere must have featured the conditions needed for supporting liquid water on its surface — another condition critical for the potential development of life. The waves' pattern indicates that they were shaped by wind-driven waves, not unlike those on the lakes and seas on Earth.

The discovery adds to our knowledge of the hydrological processes in Gale Crater, which is hypothesized to feature drainage networks and depositing systems that filled the crater over millions of years. With this new find, it appears that Mars featured a hydrological cycle on its surface at some point in its history.

On May 30, 2024, Curiosity drove over a rock on the Martian surface, splitting it open in the process. Scientists quickly noticed something odd about the rock's contents — they were made of pure sulfur crystals. And while the region Curiosity had been exploring was known to contain sulfur-based minerals like sulfate, elemental sulfur crystals were not something researchers thought they'd stumble across. If you're wondering how the rover managed to split the rock open, it's worth remembering that Curiosity weighs around 2,000 pounds and is roughly the size of a small SUV at 10 feet in length, 9 feet wide, and around 7 feet tall.

"I think it's the strangest find of the whole mission and the most unexpected," Curiosity scientist Ashwin Vasavada at the NASA Jet Propulsion Lab told CNN of the discovery. Perhaps just as strangely, Curiosity identified a whole field of rocks similar in appearance to the one it crushed, indicating that the elemental sulfur might be quite common in the area. However, the sulfur shouldn't be there, meaning scientists are now working to explain its presence. 

One of the reasons NASA scientists were inspired to look back at Curiosity's path, thus enabling them to see the crushed rock, was the experience of one of the rover's predecessors, the Spirit rover. Before ending its mission in 2010, Spirit had broken a wheel while conducting investigations and was forced to drag the wheel along as it continued its mission. This dragging stirred up white soil — silica, a material that indicates steam vents might have existed on the planet. The discovery, Vasavada says, serves as a reminder for researchers to investigate what rover activity might uncover by accident. 

One of the things Curiosity is helping us learn about the Red Planet is the composition of its atmosphere. In 2003, scientists observed large plumes of methane being emitted from the planet's surface. Since Curiosity arrived in 2012, it has continued to detect methane in the atmosphere above Gale Crater using its Sample Analysis at Mars (SAM) tunable laser spectrometer. The twist is that the methane is behaving in unpredictable ways, showing up at night and even changing with the seasons. To make matters stranger, Curiosity detected the largest methane readings in its history on the planet in 2019. However, the European Space Agency's Exo Mars Trace Gas Orbiter has detected no methane in the planet's atmosphere, meaning it's not getting trapped there either.

The origin of the methane remains a mystery, with researchers thinking it could be the result of water-rock chemistry but simultaneously being unable to rule out a biological origin story similar to the sources responsible for methane's presence on Earth. In 2024, researchers published a paper in the Journal of Geophysical Research: Planets hypothesizing that the gas might be locked under solid salt in the Martian soil that gets heated during warmer times of the day and warmer seasons, loosening the seal and allowing the methane to leak out.

Ironically, Curiosity itself might be contributing to these methane releases. The paper's authors suggest that these salt seals might crack under the weight and pressure of the 2,000-pound rover as it moves across the landscape. This would explain why methane is only being detected in Gale Crater — Curiosity's landing site and home. But considering the fact that Curiosity's instrument suite is busy taking soil samples and that gas detection is a highly resource-intensive activity for the rover, the planet's methane mystery has yet to be solved.

Today, Mars is a dry planet, but several lines of evidence point to it having a watery (and likely warmer) past billions of years ago. Fascinatingly, it appears that Mars' transition from having an Earth-like climate hosting surface water bodies to the arid desert world it is today likely wasn't a linear process. Rather, the truth about Martian climate change is more complicated. While exploring the hills of Mount Sharp in Gale Crater in recent years, Curiosity has stumbled upon evidence of water coming and going in distinct phases instead of slowly disappearing: shallow lakes, mud cracks, and debris flows all offer strong clues to such a cyclical history.

For much of 2024, Curiosity explored the Gediz Vallis channel, a winding valley-like landscape that researchers think could have been carved out by an ancient river. The valley's story is made more complex by the fact that it was later filled with rocky debris, which could be the result of debris flows (fast-moving, muddy landslides) or some other process. Either way, the debris in the valley will help scientists get a glimpse into the kind of material that sits far up on Mount Sharp, where Curiosity will never be able to reach.

"If the channel or the debris pile were formed by liquid water, that's really interesting," Curiosity project scientist Ashwin Vasavada told NASA's Jet Propulsion Laboratory about the valley. "It would mean that fairly late in the story of Mount Sharp — after a long dry period — water came back, and in a big way." (Mars' wet history goes past that though – an unassuming rock found in Indiana even helped prove there was water on Mars.)