What’s this fast-moving wave of darkness creeping across Mars?
Observations by the Mars Express orbiter reveal rapid changes on the Red Planet’s surface from windblown volcanic ash
By Joseph Howlett edited by Lee Billings
ESA/DLR/FU Berlin
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Volcanic ash is creeping across the surface of Mars with startling speed.
The European Space Agency’s (ESA’s) Mars Express mission just released a stunning orbital image showing surprising changes within Mars’s Utopia Planitia basin, which is thought to be the site of a now vanished sea. Captured by Mars Express’s High Resolution Stereo Camera (HRSC), the image shows two abutting landscapes of light and darkness, the former made from Mars’s modern-day rusted sands and the latter colored by volcanic minerals from the planet’s deep past.
ESA/DLR/FU Berlin
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A side-by-side comparison with views of the same patch recorded by NASA’s Viking orbiters in 1976 reveals a striking spread of that dark coloration. Visible changes to the Martian surface are more often marked by millions of years, not by dozens of them. This wouldn’t be the first time observers have witnessed strange waves of darkness spreading on Mars.
According to planetary scientists, this time the explanation must be the world’s strong winds. Either by blowing around surface deposits of volcanic ash from ancient eruptions or by sweeping away overlying sediments to reveal otherwise-hidden igneous rock, the winds have managed to blur the boundary between yin and yang since the last shot was taken.
The new picture also captures shadowy fractures and pits that hint at large volumes of water ice still buried beneath the surface, as well as numerous impact craters surrounded by the detritus of their own explosive formation.
Launched in 2003, ESA’s Mars Express orbiter still provides fresh views of Earth’s neighbor more than 20 years later, with each new image representing another clue in the enduring mystery of the Red Planet’s long-lost, more Earth-like past.
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