Gigantic Dust Towers On Mars Could Explain How The Red Planet Lost Its Water
Sprawling towers of dust can reach heights of 80 kilometres during global-scale dust storms on Mars, according to new research. Acting like a space elevator, the phenomenon might explain how water escaped from the Red Planet during its ancient past.
On Earth, storms tend to be highly localised events, but things are a bit different on Mars. About once a decade, Mars experiences a colossal dust storm that impacts the planet on a global scale. Known as planet-encircling dust events (PEDEs), these storms affect the planet’s weather for months at a time. Such a storm occurred in 2018—a massive global dust storm that enveloped the entire planet, casting it in a dull yellowish haze and putting an end to NASA’s Opportunity rover mission.
Two new research papers (here and here) led by Nicholas Heavens from Hampton University and the Space Sciences Institute looked at an odd meteorological phenomenon that happens during these planet-wide storms: massive towers of dust that rise up into the upper atmosphere, with some columns reaching heights of around 80 kilometres. The new papers, published in the Journal of the Atmospheric Sciences and JGR Planets, are providing new insights into these enigmatic dust towers and how they possibly contributed to water loss on Mars.
Heavens and his colleagues studied a pair of PEDEs, one from 2007 and the one from last year, to learn more about these dust towers, by looking at data collected by NASA’s Mars Reconnaissance Orbiter (MRO). This satellite is equipped with a specially designed instrument, the heat-sensing Mars Climate Sounder, that can penetrate through thick blankets of dust. The scientists also looked at images of the dust towers taken by the orbiter’s Mars Context Imager (MARCI).
That’s significant, because water vapour that’s trapped in the dust is coming along for the ride—some of which may actually be leaking into space. These dust towers could be acting as a transportation system for other materials and gases, including H2O vapour. Back in 2007, scientists observed that water molecules were being delivered to Mars’s upper atmosphere, and at heights where solar radiation causes the water molecules to break apart and waft into space. This is very possibly a clue as to how Mars lost all its water, which was once awash in lakes and rivers.
Looking ahead, the researchers would like to learn more about the dust towers and how they formed, and their possible role in removing water from Mars’ atmosphere.