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Long, dark 'streaks' spotted on Mars aren't what scientists thought

2025-06-04 20:16:00 英文原文

作者:Ben TurnerSocial Links NavigationSenior Staff Writer

An aerial image of the surface of Mars showing dark streaks across the terrain
Martian "slope streaks" spotted by NASA's Mars Reconnaissance Orbiter in 2017. Scientists previously thought these large, discolored features may be signs of running water. (Image credit: NASA/JPL-Caltech/University of Arizona)

Mysterious dark streaks flowing across Mars's surface may not be the result of running water after all, a new artificial intelligence (AI) analysis suggests.

The streaks, first observed running along Mars's cliffsides and crater walls by NASA's Viking mission in 1976, were long thought by scientists to have formed as a result of the flow of ancient water across the now mostly desiccated planet's surface.

But an AI algorithm trained on slope streak observations has revealed a different origin for the streaks — likely being formed from wind and dust, not water. The findings, published May 19 in the journal Nature Communications, could have important implications for where humans choose to explore Mars, and the places they search for evidence of possible ancient life.

"That's the advantage of this big data approach," study co-author Adomas Valantinas, a planetary scientist at Brown University, said in a statement. "It helps us to rule out some hypotheses from orbit before we send spacecraft to explore."

The sinewy lines are darker than the surrounding Martian ground and extend for hundreds of meters downhill. The shorter-lived of these features are called recurring slope lineae (RSL), and regularly spring up during Mars's warmer spells.

This led some planetary scientists to suggest that seasonal temperature fluctuations could be causing ice or frozen aquifers to melt, or humid air to condense, sending streams of salty water trickling down the planet's craters. If this were true, it would make these regions of particular interest to future Mars missions.

Related: Curiosity rover finds largest carbon chains on Mars from 3.7 billion-year-old rock

To investigate this, the scientists behind the study trained a machine learning algorithm on confirmed streak sightings before making it scan through 86,000 satellite images to create a map of 500,000 streak features.

"Once we had this global map, we could compare it to databases and catalogs of other things like temperature, wind speed, hydration, rock slide activity and other factors." Bickel said. "Then we could look for correlations over hundreds of thousands of cases to better understand the conditions under which these features form."

Using the map, the scientists found the streaks were most likely to form in places where wind speed and dust deposition was high, suggesting that they came from layers of fine dust sliding off steep slopes.

Other studies have pointed to tantalizing evidence of water and even life on Mars. If the study findings hold up, they could serve as a guide to sift between the Red Planet's useful leads and its red herrings.

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Ben Turner is a U.K. based staff writer at Live Science. He covers physics and astronomy, among other topics like tech and climate change. He graduated from University College London with a degree in particle physics before training as a journalist. When he's not writing, Ben enjoys reading literature, playing the guitar and embarrassing himself with chess.

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摘要

Mysterious dark streaks on Mars, initially thought to indicate the presence of flowing water, may instead be caused by wind and dust according to a new AI analysis published in Nature Communications. The study used machine learning algorithms trained on slope streak observations to analyze 86,000 satellite images, finding that the streaks form more frequently where wind speeds are high and dust deposition is heavy, suggesting they result from dust sliding off steep slopes rather than water flow. This could impact future Mars exploration strategies and life detection efforts.

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