The year 1976 marked a significant milestone in space exploration when NASA’s Viking mission successfully landed the first spacecraft on Mars. As the mission transmitted images from the Martian surface back to Earth, scientists observed long, dark streaks on crater walls and cliff sides. Despite ongoing debate, some researchers have suggested that these enigmatic features could be the result of water flow, but a recent study proposes an alternative explanation.

A team of planetary scientists from Brown University and the University of Bern utilized artificial intelligence to analyze the Martian streaks, concluding that they are likely caused by wind and dust rather than water flow. The findings of this study have significant implications for future Mars exploration and the ongoing search for habitable environments and life beyond Earth.

Certain slope streaks are long-lasting, while others, known as recurring slope lineae (RSL), appear and disappear in the same locations during the hottest times of the year on Mars. Although Mars is generally characterized by dry and cold conditions (with temperatures as low as -225 degrees Fahrenheit, or -153 degrees Celsius), it is theoretically possible for small amounts of water from potential ice, underground sources, or humidity to mix with sufficient salt to become liquid and flow down a slope. Given that water is essential for life on Earth, such formations could potentially represent habitable regions on Mars as well. However, some researchers argue that dry processes could also be responsible for these features.

To resolve this issue, the researchers employed an algorithm trained on a dataset of confirmed slope streak sightings, as outlined in a study published in the journal Nature Communications. The algorithm was then used to scan over 86,000 high-resolution satellite images, resulting in a comprehensive map of Martian slope streaks.

“With this global map in hand, we were able to compare it to databases and catalogs of factors such as temperature, wind speed, hydration, rock slide activity, and others,” explained Valentin Bickel, co-author of the study and a fellow at the University of Bern Center for Space and Habitability, in a statement released by Brown University. “This allowed us to look for correlations across hundreds of thousands of cases, providing valuable insights into the conditions under which these features form.”

In simple terms, the study’s findings do not support a link between slope streaks and RSLs and features indicative of liquid or frost presence. Instead, the researchers discovered that both slope streaks and RSLs tend to develop in areas with high wind speeds and dust deposition, suggesting that they are likely the result of a dry process involving the abrupt sliding of dust layers down a slope, triggered by external forces.

Rather than viewing these results as a setback in the search for extraterrestrial life, the planetary scientists emphasize that the study still holds significance for future Mars explorations. If the research had confirmed that slope streaks were caused by water, indicating potential habitability and life, NASA would have avoided the area to prevent contamination from terrestrial life, such as microbes, which could interfere with the search for Martian life.

“The advantage of this big data approach lies in its ability to help us rule out certain hypotheses from orbit before we send spacecraft to explore,” explained Adomas Valantinas, co-author of the study and a planetary scientist at Brown University specializing in Martian geology.

In an industry where the discovery of water on Mars and evidence of liquid water is a major focus, this study serves as a reminder that not every scientific breakthrough needs to be centered on extraterrestrial life.