Mars' “tilt streaks” revealed by NASA's Mars Reconnaissance Orbiter in 2017. These large, colorless features were previously thought to indicate the presence of flowing water. (Image credit: NASA/JPL-Caltech/University of Arizona)
A new analysis using artificial intelligence (AI) suggests that mysterious dark streaks running across the surface of Mars may not be caused by moving water.
Scientists have long believed that the streaks first spotted on the slopes and walls of Mars' craters during NASA's Viking mission in 1976 were formed by ancient water flowing across the now-waterless planet.
But an AI algorithm trained on the tilt-streak data found a different origin for the features — perhaps created by wind and dust rather than water. The findings, published May 19 in Nature Communications, could have significant implications for future Mars exploration and the search for signs of possible ancient life.
“That’s the benefit of the big data approach,” said study co-author Adomas Valantinas, a planetary scientist at Brown University, in a commentary. “It allows us to rule out some hypotheses from orbit before we send a spacecraft to study it in detail.”
The deepened lines are darker than the surrounding Martian surface and extend hundreds of meters down the slope. The shorter-lived of these features are called recurring slope lineations (RSLs) and appear regularly during warmer seasons on Mars.
This has led some planetary scientists to speculate that seasonal temperature variations could cause ice or frozen aquifers to melt or moist air to condense, causing salty water to flow down the planet's craters. If true, these regions would be of particular interest to future missions to Mars.
To study this question, the researchers trained a machine learning algorithm on verified stripe data and then analyzed 86,000 satellite images, creating a map of 500,000 stripe features.
“Once we had created this global map, we could compare it to databases and catalogs of other factors, such as temperature, wind speed, hydration levels, landslide activity, and other parameters,” Bickel explained. “We could then look for correlations across hundreds of thousands of cases to better understand the conditions under which these features form.”
Using the map, the scientists found that the streaks were most likely to occur in areas with high wind speeds and dust accumulation, suggesting that they were formed from layers of fine dust sliding down steep slopes.
Other studies have provided intriguing evidence of water and even life on Mars. If confirmed, this study could provide a basis for weeding out useful clues about the Red Planet and its false trails.
TOPICS water Life on Mars
Ben TurnerNavigate Social LinksSenior Staff Writer
Ben Turner is a staff writer for Live Science based in the UK. He covers physics and astronomy, as well as topics like technology and climate change. He studied particle physics at University College London before becoming a journalist. When he’s not writing, Ben enjoys reading, playing guitar, and chess.
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