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By NASA
In northwest Australia, the Great Sandy Desert holds great geological interest as a zone of active sand dune movement. While a variety of dune forms appear across the region, this astronaut photograph features numerous linear dunes (about 25 meters high) separated in a roughly regular fashion (0.5 to 1.5 kilometers apart).NASA On March 25, 2013, an astronaut aboard the International Space Station took this photo of the Great Sandy Desert in northwest Australia, showcasing linear dunes separated in a roughly regular fashion. When you fly over such dune fields—either in an airplane or the space station—the fire scars stand out. Where thin vegetation has been burned, the dunes appear red from the underlying sand; dunes appear darker where the vegetation remains.
Strings of narrow lakes that represent ancient rivers are also present in the region. The white feature down the center of the image is Lake Auld. The color is the result of a cemented combination of fine, clay-like sediment and salts from the evaporation of flood waters that occasionally fill the lake. Linear dunes can be seen entering Lake Auld on the east side. During flooding events, the sand of the dune noses is dispersed, becoming incorporated into the muds and salts of the lake floor sediments. During the long, intervening dry periods, sand can blow across the lake floor to build thinner, smaller dunes, visible as linear accumulations on the west side of the lake.
See more photos taken by astronauts.
Text credit: NASA/M. Justin Wilkinson
Image credit: NASA
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By European Space Agency
This new snapshot from the European Space Agency’s Mars Express deftly captures the two distinct faces of Mars: ridged and rugged versus smooth and unmarked.
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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
A Martian dust devil can be seen consuming its smaller friend in this short video made of images taken at the rim of Jezero Crater by NASA’s Perseverance Mars rover on Jan. 25, 2025. NASA/JPL-Caltech/SSI The six-wheeled explorer recently captured several Red Planet mini-twisters spinning on the rim of Jezero Crater.
A Martian dust devil can be seen consuming a smaller one in this short video made of images taken by a navigation camera aboard NASA’s Perseverance Mars rover. These swirling, sometimes towering columns of air and dust are common on Mars. The smaller dust devil’s demise was captured during an imaging experiment conducted by Perseverance’s science team to better understand the forces at play in the Martian atmosphere.
When the rover snapped these images from about 0.6 miles (1 kilometer) away, the larger dust devil was approximately 210 feet (65 meters) wide, while the smaller, trailing dust devil was roughly 16 feet (5 meters) wide. Two other dust devils can also be seen in the background at left and center. Perseverance recorded the scene Jan. 25 as it explored the western rim of Mars’ Jezero Crater at a location called “Witch Hazel Hill.”
“Convective vortices — aka dust devils — can be rather fiendish,” said Mark Lemmon, a Perseverance scientist at the Space Science Institute in Boulder, Colorado. “These mini-twisters wander the surface of Mars, picking up dust as they go and lowering the visibility in their immediate area. If two dust devils happen upon each other, they can either obliterate one another or merge, with the stronger one consuming the weaker.”
While exploring the rim of Jezero Crater on Mars, NASA’s Perseverance rover captured new images of multiple dust devils in January 2025. These captivating phenomena have been documented for decades by the agency’s Red Planet robotic explorers. NASA/JPL-Caltech/LANL/CNES/CNRS/INTA-CSIC/Space Science Institute/ISAE-Supaero/University of Arizona Science of Whirlwinds
Dust devils are formed by rising and rotating columns of warm air. Air near the planet’s surface becomes heated by contact with the warmer ground and rises through the denser, cooler air above. As other air moves along the surface to take the place of the rising warmer air, it begins to rotate. When the incoming air rises into the column, it picks up speed like a spinning ice skater bringing their arms closer to their body. The air rushing in also picks up dust, and a dust devil is born.
“Dust devils play a significant role in Martian weather patterns,” said Katie Stack Morgan, project scientist for the Perseverance rover at NASA’s Jet Propulsion Laboratory in Southern California. “Dust devil study is important because these phenomena indicate atmospheric conditions, such as prevailing wind directions and speed, and are responsible for about half the dust in the Martian atmosphere.”
NASA’s Viking 1 orbiter captured this Martian dust devil casting a shadow on Aug. 1, 1978. During the 15-second interval between the two images, the dust devil moved toward the northeast (toward the upper right) at a rate of about 59 feet (18 meters) per second. NASA/JPL-Caltech/MSSS Since landing in 2021, Perseverance has imaged whirlwinds on many occasions, including one on Sept. 27, 2021, where a swarm of dust devils danced across the floor of Jezero Crater and the rover used its SuperCam microphone to record the first sounds of a Martian dust devil.
NASA’s Viking orbiters, in the 1970s, were the first spacecraft to photograph Martian dust devils. Two decades later, the agency’s Pathfinder mission was the first to image one from the surface and even detected a dust devil passing over the lander. Twin rovers Spirit and Opportunity managed to capture their fair share of dusty whirlwinds. Curiosity, which is exploring a location called Mount Sharp in Gale Crater on the opposite side of the Red Planet as Perseverance, sees them as well.
Capturing a dust devil image or video with a spacecraft takes some luck. Scientists can’t predict when they’ll appear, so Perseverance routinely monitors in all directions for them. When scientists see them occur more frequently at a specific time of day or approach from a certain direction, they use that information to focus their monitoring to try to catch additional whirlwinds.
“If you feel bad for the little devil in our latest video, it may give you some solace to know the larger perpetrator most likely met its own end a few minutes later,” said Lemmon. “Dust devils on Mars only last about 10 minutes.”
More About Perseverance
A key objective of Perseverance’s mission on Mars is astrobiology, including caching samples that may contain signs of ancient microbial life. The rover is characterizing the planet’s geology and past climate, to help pave the way for human exploration of the Red Planet and as the first mission to collect and cache Martian rock and regolith.
NASA’s Mars Sample Return Program, in cooperation with ESA (European Space Agency), is designed to send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.
The Mars 2020 Perseverance mission is part of NASA’s Mars Exploration Program (MEP) portfolio and the agency’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.
NASA’s Jet Propulsion Laboratory, which is managed for the agency by Caltech, built and manages operations of the Perseverance rover.
For more about Perseverance:
https://science.nasa.gov/mission/mars-2020-perseverance
News Media Contacts
DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle@jpl.nasa.gov
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
2025-047
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Last Updated Apr 03, 2025 Related Terms
Perseverance (Rover) Curiosity (Rover) Jet Propulsion Laboratory Mars Mars 2020 Mars Exploration Rovers (MER) Mars Pathfinder Viking Explore More
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By NASA
NASA/JPL-Caltech/MSSS NASA’s Curiosity Mars rover captured this feather-shaped iridescent cloud just after sunset on Jan. 27, 2023. Studying the colors in iridescent clouds tells scientists something about particle size within the clouds and how they grow over time. These clouds were captured as part of a seasonal imaging campaign to study noctilucent, or “night-shining” clouds. A new campaign in January 2025 led to Curiosity capturing this video of red- and green-tinged clouds drifting through the Martian sky.
Learn more about iridescent twilight clouds on Mars.
Image credit: NASA/JPL-Caltech/MSSS
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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
It’s a new year on Mars, and while New Year’s means winter in Earth’s northern hemisphere, it’s the start of spring in the same region of the Red Planet. And that means ice is thawing, leading to all sorts of interesting things. JPL research scientist Serina Diniega explains. NASA/JPL-Caltech Instead of a winter wonderland, the Red Planet’s northern hemisphere goes through an active — even explosive — spring thaw.
While New Year’s Eve is around the corner here on Earth, Mars scientists are ahead of the game: The Red Planet completed a trip around the Sun on Nov. 12, 2024, prompting a few researchers to raise a toast.
But the Martian year, which is 687 Earth days, ends in a very different way in the planet’s northern hemisphere than it does in Earth’s northern hemisphere: While winter’s kicking in here, spring is starting there. That means temperatures are rising and ice is thinning, leading to frost avalanches crashing down cliffsides, carbon dioxide gas exploding from the ground, and powerful winds helping reshape the north pole.
“Springtime on Earth has lots of trickling as water ice gradually melts. But on Mars, everything happens with a bang,” said Serina Diniega, who studies planetary surfaces at NASA’s Jet Propulsion Laboratory in Southern California.
Mars’ wispy atmosphere doesn’t allow liquids to pool on the surface, like on Earth. Instead of melting, ice sublimates, turning directly into a gas. The sudden transition in spring means a lot of violent changes as both water ice and carbon dioxide ice — dry ice, which is much more plentiful on Mars than frozen water — weaken and break.
“You get lots of cracks and explosions instead of melting,” Diniega said. “I imagine it gets really noisy.”
Using the cameras and other sensors aboard NASA’s Mars Reconnaissance Orbiter (MRO), which launched in 2005, scientists study all this activity to improve their understanding of the forces shaping the dynamic Martian surface. Here’s some of what they track.
Frost Avalanches
In 2015, MRO’s High-Resolution Imaging Science Experiment (HiRISE) camera captured a 66-foot-wide (20-meter-wide) chunk of carbon dioxide frost in freefall. Chance observations like this are reminders of just how different Mars is from Earth, Diniega said, especially in springtime, when these surface changes are most noticeable.
Martian spring involves lots of cracking ice, which led to this 66-foot-wide (20-meter-wide) chunk of carbon dioxide frost captured in freefall by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter in 2015NASA/JPL-Caltech/University of Arizona “We’re lucky we’ve had a spacecraft like MRO observing Mars for as long as it has,” Diniega said. “Watching for almost 20 years has let us catch dramatic moments like these avalanches.”
Gas Geysers
Diniega has relied on HiRISE to study another quirk of Martian springtime: gas geysers that blast out of the surface, throwing out dark fans of sand and dust. These explosive jets form due to energetic sublimation of carbon dioxide ice. As sunlight shines through the ice, its bottom layers turn to gas, building pressure until it bursts into the air, creating those dark fans of material.
As light shines through carbon dioxide ice on Mars, it heats up its bottom layers, which, rather than melting into a liquid, turn into gas. The buildup gas eventually results in explosive geysers that toss dark fans of debris on to the surface.light shines through carbon dioxide ice on Mars But to see the best examples of the newest fans, researchers will have to wait until December 2025, when spring starts in the southern hemisphere. There, the fans are bigger and more clearly defined.
Spiders
Another difference between ice-related action in the two hemispheres: Once all the ice around some northern geysers has sublimated in summer, what’s left behind in the dirt are scour marks that, from space, look like giant spider legs. Researchers recently re-created this process in a JPL lab.
Sometimes, after carbon dioxide geysers have erupted from ice-covered areas on Mars, they leave scour marks on the surface. When the ice is all gone by summer, these long scour marks look like the legs of giant spiders.NASA/JPL-Caltech/University of Arizona Powerful Winds
For Isaac Smith of Toronto’s York University, one of the most fascinating subjects in springtime is the Texas-size ice cap at Mars’ north pole. Etched into the icy dome are swirling troughs, revealing traces of the red surface below. The effect is like a swirl of milk in a café latte.
“These things are enormous,” Smith said, noting that some are a long as California. “You can find similar troughs in Antarctica but nothing at this scale.”
As temperatures rise, powerful winds kick up that carve deep troughs into the ice cap of Mars’ north pole. Some of these troughs are as long as California, and give the Martian north pole its trademark swirls. This image was captured by NASA’s now-inactive Mars Global Surveyor.NASA/JPL-Caltech/MSSS Fast, warm wind has carved the spiral shapes over eons, and the troughs act as channels for springtime wind gusts that become more powerful as ice at the north pole starts to thaw. Just like the Santa Ana winds in Southern California or the Chinook winds in the Rocky Mountains, these gusts pick up speed and temperature as they ride down the troughs — what’s called an adiabatic process.
Wandering Dunes
The winds that carve the north pole’s troughs also reshape Mars’ sand dunes, causing sand to pile up on one side while removing sand from the other side. Over time, the process causes dunes to migrate, just as it does with dunes on Earth.
This past September, Smith coauthored a paper detailing how carbon dioxide frost settles on top of polar sand dunes during winter, freezing them in place. When the frost all thaws away in the spring, the dunes begin migrating again.
Surrounded by frost, these Martian dunes in Mars’ northern hemisphere were captured from above by NASA’s Mars Reconnaissance Orbiter using its HiRISE camera on Sept. 8, 2022. NASA/JPL-Caltech/University of Arizona Each northern spring is a little different, with variations leading to ice sublimating faster or slower, controlling the pace of all these phenomena on the surface. And these strange phenomena are just part of the seasonal changes on Mars: the southern hemisphere has its own unique activity.
More About MRO
The University of Arizona, in Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., in Boulder, Colorado. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA’s Science Mission Directorate, Washington.
For more information, visit:
https://science.nasa.gov/mission/mars-reconnaissance-orbiter
News Media Contacts
Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good@jpl.nasa.gov
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
2024-177
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Last Updated Dec 20, 2024 Related Terms
Mars Reconnaissance Orbiter (MRO) Jet Propulsion Laboratory Mars Explore More
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