SPACE/COSMOS
‘Serendipitous’ discovery of Martian ripple marks reveals an ancient sandstorm
New research in Geology uses images from the Curiosity rover to decode the planet’s atmosphere at a time when the surface was potentially habitable
image:
Fig 1: A closer view of the supercritical climbing wind ripples that provide direct evidence of a sandstorm, roughly three and a half billion years ago.
view moreCredit: NASA/JPL-Caltech/MSSS
The search for life on Mars involves the efforts of scientists from many different disciplines. An important aspect of that search is to study Martian sedimentary rocks for information about the planet’s environment when it is likely that the surface environment hosted abundant water and therefore more habitable, around three to four billion years ago. Now, new research published in the journal Geology shows evidence of an intense sandstorm that swept through Mars’ Gale crater over three billion years ago.
“Everybody knows that the wind blew on Mars. There was an atmosphere, so it must have moved, forming breezes and gusts, and so there must have been storms, too. But this is the first definitive evidence that we've found of such a sandstorm,” says Steven Banham, a planetary geologist at Imperial College London and lead author of the new study. “While it does not contribute to proving existence of life on Mars, it helps paint a rich picture of the ancient surface environment.”
The finding comes from the discovery of ripple structures by Banham and a team of scientists working with the Curiosity rover. These windblown sedimentary structures were formed in a desert environment, and resemble millimeter-thick “crinkly” laminations, says Banham. Wind ripple strata like this are rarely found on Earth and have never before been observed on Mars. They can only be formed when sustained winds move large amounts of loose sand. While most sedimentary structures preserved in desert rocks on Earth or Mars record longer-term trends from seasonal winds to several thousands of years, supercritical climbing wind ripples document evidence of storms that lasted only minutes to hours.
“The thing that absolutely amazes me, is you just think that on a Tuesday afternoon, sometime, maybe 3.6 billion or so years ago, there was a sandstorm that rolled into Gale crater,” says Banham. “It would be like one of those scenes in [the movie] Dune where there's a sandstorm happening and these ripple structures would be forming as a result. Then maybe the next day, the wind returns to normal, and it's just another sunny day in Gale crater. But that sandstorm happened, and we have the physical evidence for it here.”
The discovery involved a degree of luck. As the Curiosity rover navigates the Martian surface, a rotating team of scientists monitor its camera and other instruments. Banham and his colleagues, including Linda Kah from the University of Tennessee and Joel Davis from Imperial College London, noticed unusual features in a black and white panorama taken at the end of each drive. The team decided to target them with higher-resolution MASTCAM cameras. Upon closer inspection, they realized they were looking at unique ripples.
“This was very serendipitous. We weren't really looking for these deposits, and then lo and behold, we drove around the corner and found them,” says Banham. “We were lucky that we had just the right people on shift that recognized them.”
Direct evidence of the pressure and composition of the martian atmosphere over 3.5 billion years ago is hard to come by, but scientists know that the current martian atmosphere isn’t dense enough to move sand with wind on this scale. This research provides insight into the ancient conditions and suggests they were much higher and likely closer to that of Earth than they are currently.
“These deposits in themselves indicate that the atmosphere was denser at the time than it is now, to form these structures,” says Banham
Going forward, Banham hopes for similar serendipitous discoveries. One of the most exciting possibilities is to find rain impact marks. “People have been looking for those since Pathfinder and the MER rovers, and nobody's seen them,” says Banham, referring to the first Martian landings in the late 1990s and early 2000s. “It must have rained, as we’ve seen evidence of rivers and lake deposits. But we've not got that definitive evidence of rain until we see rain impacts. That would be magic if we found those.”
Citation: Banham, S., et al., 2026, An ancient sandstorm recorded by supercritical climbing wind ripple strata in Gale crater, Mars; Geology: https://doi.org/10.1130/G54158.1
About the Geological Society of America
The Geological Society of America (GSA) is a global professional society with more than 18,000 members across over 100 countries. As a leading voice for the geosciences, GSA advances the understanding of Earth's dynamic processes and fosters collaboration among scientists, educators, and policymakers. GSA publishes Geology, the top-ranked “geology” journal, along with a diverse portfolio of scholarly journals, books, and conference proceedings—several of which rank among Amazon’s top 100 best-selling geology titles.
A wide view of the area where the Mars Science Laboratory science team discovered evidence of an ancient sandstorm.
Credit
NASA/JPL-Caltech
Journal
Geology
Article Title
An ancient sandstorm recorded by supercritical climbing wind ripple strata in Gale crater, Mars
Providing the Artemis mission with solar radiation forecasts
The University of Michigan will participate in a demonstration of new technologies that could warn NASA of solar particle radiation hazards up to 24 hours in advance
University of Michigan
Key takeaways
NASA will monitor University of Michigan Engineering's solar particle forecasts during the Artemis II mission to maintain situational awareness of impending harmful radiation released during solar flares and eruptions, which could create conditions in which astronauts take safety precautions.
The warnings will come from a machine-learning model using satellite images of the sun and corona to forecast solar particle storms up to 24 hours in advance.
The researchers also developed a physics-based model that will estimate the severity of hazardous radiation created by solar flares or eruptions, and NASA has devoted high-performance computing resources to run it.
In the Artemis II mission, NASA will test out a pair of new solar radiation forecasts, developed at University of Michigan Engineering, designed to protect astronauts venturing away from Earth. The mission launched Wednesday.
The forecasts will provide warnings of harmful solar radiation released by solar flares and eruptions up to 24 hours in advance. NASA's Space Radiation Analysis Group, or SRAG, is examining how new solar particle forecasting technologies might provide a faster response to changing space weather conditions during the Artemis missions, which will mostly fly outside the natural shielding provided by the Earth's magnetic field.
Artemis II is also launching during the most active period of the sun's 11-year cycle in sunspot count, when eruptions are more common. An energetic solar flare, which is sometimes a precursor to particle storms, occurred just this week.
The harmful radiation comes from protons, the positively-charged particles inside the cores of all atoms. Protons freely fly through the solar wind, the stream of electrically conductive gas that emanates from the sun, and they become especially dangerous when accelerated by the shock waves from solar flares and eruptions. The particles can travel near the speed of light and reach Earth minutes after a solar eruption.
If they hit an astronaut, their high energies could cause DNA strand breaks or cellular damage that may lead to an increased risk of developing cancer in the long-term. At very high doses, associated with only the very rare top 5% of all solar particle events, effects like nausea might be possible without sufficient shielding. However, the Orion vehicle was built to provide significant shielding for the Artemis astronauts that will keep them well below those harmful dose levels.
In the event of bad space weather, the Artemis crew is trained to reconfigure their cabin to reduce radiation exposure, according to a NASA statement. By removing stowed equipment from storage bays and securing it along areas of the cabin, the crew will add a thicker barrier between themselves and the harmful particles. With the extra shielding, the crew can go about their business.
Keeping an eye on the sun
SRAG console operators monitoring radiation sensors in the Orion spacecraft will alert Mission Control to let the crew know if they suddenly need to rearrange the cabin. To potentially provide more prep time, Michigan Engineering's machine-learning model forecasts the chance of dangerous solar radiation, similar to the hourly percent chance of rain in a conventional weather forecast. Each day of the mission, it will calculate the probability of harmful radiation in a demonstration of the feasibility of this new technology.
The model makes its predictions using satellite images of the sun and corona. Those pictures are snapped by two spacecraft: the Solar Dynamics Observatory, or SDO, which photographs the entire sun and its magnetic field in visible and UV light, and the Solar and Heliospheric Observatory, or SOHO, which photographs the sun's corona and takes readings of the corona's particles and chemical elements.
"We are looking at the sun 24/7, specifically the magnetic evolution of the sun and events such as flares and eruptions, to see if any extra energy will be released," said Lulu Zhao, U-M assistant professor of climate and space sciences and engineering and the principal investigator of the CLEAR Center, which NASA funded to develop the forecasting tools.
The machine-learning model was trained using a catalog of photos compiled from data collected since the launch of each instrument—2010 for SDO and 1995 for SOHO. From the photos, the model learned to identify what the sun looks like right before a particle storm. But the model only calculates the probability of a dangerous particle storm. It doesn't provide any details on the storm, or how long it will last.
To provide those details, the researchers also developed a physics-based model that estimates when solar flares and eruptions will trigger a particle storm at Earth and the moon, and for how long hazardous levels of radiation will stick around. The model's predictions are more sophisticated than existing solar particle storm models because it simulates solar energetic particles in the corona, where particle acceleration starts and is strongest.
The new capability comes from a model of the solar corona, published by U-M scientists in 2014. There is only one reliable alternative to model the sun's corona, but it's too slow for operational forecasts.
The physics-based model will also constantly run throughout the mission, but it needs to be updated by a human whenever the sun erupts. NASA's Moon to Mars office will upload measurements of solar eruption speeds to a database. The U-M model will automatically take the new measurements to estimate radiation exposure.
"We asked NASA to reserve 3,000 processing units on their supercomputer for us during the mission, so the model can run as quickly as possible whenever there is an eruption," Zhao said. "We can't afford delays because the harmful particles can reach Earth so quickly."
Written by Derek Smith
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