Throughout the history of astronomical studies, experts did not stop at observing the dark landslides that occurred on the Martian plains. These terrains are called slope streaks, first discovered by scientists in the 1970s. To date, every orbiter from various space agencies has data on these landslides during their respective missions.
Despite the slope streaks, the scientific community is still divided about how they originated on the red planet. Many experts believe that these dark terrains are induced by the hidden water on Mars, while others suspect that it is simply a product of dry mechanics.
Slope Streaks: Mysterious Hair Strands on Mars
This image from NASA's Mars Reconnaissance Orbiter (MRO) shows streaks forming on slopes when dust cascades downhill. The dark streak is an area of less dust compared to the brighter and reddish surroundings. What triggers these avalanches is unknown but might be related to the sudden warming of the surface.
In recent studies, it was shown that the slope streaks are likely formed due to the latter. But a new paper suggests that neither of the guesses is correct. With the help of the Mars Odyssey mission, astronomers discovered that the factor allowing these disruptions on the Martian surface is carbon dioxide frost.
The slope streaks commonly manifest in regions inside the wall of craters and the mountains and hills on Mars. Past research explained that the rocks and dust on these slopes could be easily disturbed by as simple as dust devils to larger activities such as an impact event, SciTechDaily reports.
Experts theorize carbon dioxide is one of the leading factors of dislodged rocks behind the avalanches of the red planet's surface. The latest study backed up this idea through the data collected by the Odyssey spacecraft.
Since 2001, the vehicle has been actively gathering information on Mars. To date, it is the longest-running mission deployed to the planet. Every 7 AM, the Odyssey captures images of the slope streaks from the red planet. The observation over the first activity is most effective during this time due to the natural light that the sun provides.
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Dirty Frosts
One of the most notable events related to the Martian landslides was witnessed last year. The images that the Odyssey spacecraft captured showed ghostly blue and white features from the planet's surface. When analyzed through the vessel's Thermal Emission Imaging System (THEMIS), the frost appeared wider even though the physical camera did not detect further textures.
NASA explained that due to the thin atmosphere present on Mars, which measures just one percent of Earth's cover, the sun could quickly warm these frosts that materialize overnight. And because of the lack of components from the Martian sky, the dry ice evaporates instead of being melted. This process happens just a few minutes after the sunrise on the planet.
The unusual hair-like strands on the surface are considered 'dirty frosts,' a product of a combination of dry ice first and fine grains of dust. These are more visible in images with light rather than through infrared captures. The dirty frost might also be the origin of the dark streaks that stretch to approximately 1,000 meters or 3,300 feet across Mars.
The study was published in the Journal of Geophysical Research: Planets, titled "Gardening of the Martian Regolith by Diurnal CO2 Frost and the Formation of Slope Streaks.
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