- Mars had lakes on its surface billions of years ago, scientists believe. But was this liquid water on Mars open to the air, with waves, or were the lakes covered in ice?
- The Mars rover Curiosity has found evidence for ripples on lakes in Gale crater. As on Earth, the ripples must have been driven by winds.
- So the lakes weren’t covered in ice, this evidence suggests. If so, conditions must have been warm enough on Mars for ice-free lakes, which, this study suggests, existed on Mars for longer then previously thought.
Were lakes on Mars frozen solid?
We know that lakes existed on Mars’ surface billions of years ago. But scientists have debated whether the lakes were open to the air or covered by a layer of ice. Now, researchers in the U.S., U.K. and France have released a new study showing that at least some Martian lakes must have been ice-free. The researchers said on January 15, 2025, that NASA’s Curiosity rover on Mars has now examined layers in rock outcrops in Gale crater. The ancient rocks show evidence of wind-driven ripples on former Martian lakes or ponds.
The researchers published their peer-reviewed findings in Science Advances, also on January 15.
Researchers from @Caltech have identified ancient wave ripples on Mars, indicating the presence of long-gone, ice-free ponds and lakes.
These ripples, discovered by NASA's Curiosity rover in the Gale Crater region, are small undulations formed by wind-driven water, suggesting… pic.twitter.com/1XiGVqozZz
— Erika ? (@ExploreCosmos_) January 16, 2025
Wind-blown ripples on ancient Mars lakes
Evidence of ripples on lakes or other bodies of water can be preserved in rock layers. The Curiosity rover has found such evidence in Gale crater on Mars. The mission team estimates these rocks to be about 3.7 billion years old. That’s nearly as old as our sun; its estimated age is 4.5 billion years. So the rocks are very old. And Curiosity – which has been exploring Gale crater on Mars since 2012 – first found the two sets of ripples in 2022. The first set, at the Prow rock outcrop, is in a region that once contained wind-blown sand dunes. The second set is nearby, in the Amapari Marker Band rock outcrop.
Interestingly, the Amapari Marker Band ripples formed a bit later in Mars’ history than the Prow ripples. The scientists said this means that conditions for their formation – i.e. for liquid water – were suitable at multiple times.
In addition, these ripples formed during a period of Mars’ past when the planet was becoming drier and losing its water. Or at least that’s what scientists thought. This new evidence would suggest that Mars was able to hold on to its water at least a bit longer than previously estimated. Lead author Claire Mondro at the California Institute of Technology (Caltech) in California said:
Extending the length of time that liquid water was present extends the possibilities for microbial habitability later into Mars’ history.
The ripples were small, only about 0.2 inches (6 millimeters) high and spaced less than 2 inches (4 to 5 centimeters) apart. This suggests the lake was shallow, less than 6.5 feet (2 meters) deep.
Ice-free lakes and ponds
The findings are significant for a couple of reasons. Not only do they show that – as has previous evidence from Curiosity – that there were lakes and ponds in Gale crater, but that they were ice-free. Some climate models for Mars’ past suggest that any lakes on Mars probably were covered by ice. But the new study suggests otherwise. Mondro said:
The shape of the ripples could only have been formed under water that was open to the atmosphere and acted upon by wind.
This is important, because it means conditions must have been warm enough for lakes to exist without a covering of ice. As the paper stated:
Symmetrical wave ripples identified with NASA’s Curiosity rover in ancient lake deposits at Gale crater provide a key paleoclimate constraint for early Mars. At the time of ripple formation, climate conditions must have supported ice-free liquid water on the surface of Mars. Their presence suggests formation in a shallow-water (<2 meters) setting that was open to the atmosphere, which requires atmospheric conditions that allow stable surface water.
Previous evidence for ripples
The Opportunity rover in Meridiani Planum also discovered evidence for water ripples after its mission began in 2004. It wasn’t clear, however, whether that water actually formed standing lakes or ponds. Now, the confirmation from Curiosity for ripples on ice-free lakes is an important discovery. John Grotzinger at Caltech, former project scientist for Curiosity, explained:
The discovery of wave ripples is an important advance for Mars paleoclimate science. We have been searching for these features since the Opportunity and Spirit landers began their missions in 2004. Earlier missions, beginning with Opportunity in 2004, discovered ripples formed by water flowing across the surface of ancient Mars, but it was uncertain if that water ever pooled to form lakes or shallow seas. The Curiosity rover discovered evidence for long-lived ancient lakes in 2014, and now 10 years later Curiosity has discovered ancient lakes that were free of ice, offering an important insight into the planet’s early climate.
Since the lakes were warm enough to not freeze over, could there have been any microbes swimming in them? We don’t know, but it’s an exciting possibility to contemplate!
Bottom line: At least some ancient lakes on Mars were ice-free. NASA’s Curiosity rover discovered evidence for small wind-blown ripples on the former lakes in Gale crater.
Source: Wave ripples formed in ancient, ice-free lakes in Gale crater, Mars
Read more: Ancient Mars lake was larger than any on Earth
Read more: Did this Mars rock once lie along an ancient lakeshore?
The post Lakes on Mars had ripples! They must have been ice-free first appeared on EarthSky.
from EarthSky https://ift.tt/JfA35XV
- Mars had lakes on its surface billions of years ago, scientists believe. But was this liquid water on Mars open to the air, with waves, or were the lakes covered in ice?
- The Mars rover Curiosity has found evidence for ripples on lakes in Gale crater. As on Earth, the ripples must have been driven by winds.
- So the lakes weren’t covered in ice, this evidence suggests. If so, conditions must have been warm enough on Mars for ice-free lakes, which, this study suggests, existed on Mars for longer then previously thought.
Were lakes on Mars frozen solid?
We know that lakes existed on Mars’ surface billions of years ago. But scientists have debated whether the lakes were open to the air or covered by a layer of ice. Now, researchers in the U.S., U.K. and France have released a new study showing that at least some Martian lakes must have been ice-free. The researchers said on January 15, 2025, that NASA’s Curiosity rover on Mars has now examined layers in rock outcrops in Gale crater. The ancient rocks show evidence of wind-driven ripples on former Martian lakes or ponds.
The researchers published their peer-reviewed findings in Science Advances, also on January 15.
Researchers from @Caltech have identified ancient wave ripples on Mars, indicating the presence of long-gone, ice-free ponds and lakes.
These ripples, discovered by NASA's Curiosity rover in the Gale Crater region, are small undulations formed by wind-driven water, suggesting… pic.twitter.com/1XiGVqozZz
— Erika ? (@ExploreCosmos_) January 16, 2025
Wind-blown ripples on ancient Mars lakes
Evidence of ripples on lakes or other bodies of water can be preserved in rock layers. The Curiosity rover has found such evidence in Gale crater on Mars. The mission team estimates these rocks to be about 3.7 billion years old. That’s nearly as old as our sun; its estimated age is 4.5 billion years. So the rocks are very old. And Curiosity – which has been exploring Gale crater on Mars since 2012 – first found the two sets of ripples in 2022. The first set, at the Prow rock outcrop, is in a region that once contained wind-blown sand dunes. The second set is nearby, in the Amapari Marker Band rock outcrop.
Interestingly, the Amapari Marker Band ripples formed a bit later in Mars’ history than the Prow ripples. The scientists said this means that conditions for their formation – i.e. for liquid water – were suitable at multiple times.
In addition, these ripples formed during a period of Mars’ past when the planet was becoming drier and losing its water. Or at least that’s what scientists thought. This new evidence would suggest that Mars was able to hold on to its water at least a bit longer than previously estimated. Lead author Claire Mondro at the California Institute of Technology (Caltech) in California said:
Extending the length of time that liquid water was present extends the possibilities for microbial habitability later into Mars’ history.
The ripples were small, only about 0.2 inches (6 millimeters) high and spaced less than 2 inches (4 to 5 centimeters) apart. This suggests the lake was shallow, less than 6.5 feet (2 meters) deep.
Ice-free lakes and ponds
The findings are significant for a couple of reasons. Not only do they show that – as has previous evidence from Curiosity – that there were lakes and ponds in Gale crater, but that they were ice-free. Some climate models for Mars’ past suggest that any lakes on Mars probably were covered by ice. But the new study suggests otherwise. Mondro said:
The shape of the ripples could only have been formed under water that was open to the atmosphere and acted upon by wind.
This is important, because it means conditions must have been warm enough for lakes to exist without a covering of ice. As the paper stated:
Symmetrical wave ripples identified with NASA’s Curiosity rover in ancient lake deposits at Gale crater provide a key paleoclimate constraint for early Mars. At the time of ripple formation, climate conditions must have supported ice-free liquid water on the surface of Mars. Their presence suggests formation in a shallow-water (<2 meters) setting that was open to the atmosphere, which requires atmospheric conditions that allow stable surface water.
Previous evidence for ripples
The Opportunity rover in Meridiani Planum also discovered evidence for water ripples after its mission began in 2004. It wasn’t clear, however, whether that water actually formed standing lakes or ponds. Now, the confirmation from Curiosity for ripples on ice-free lakes is an important discovery. John Grotzinger at Caltech, former project scientist for Curiosity, explained:
The discovery of wave ripples is an important advance for Mars paleoclimate science. We have been searching for these features since the Opportunity and Spirit landers began their missions in 2004. Earlier missions, beginning with Opportunity in 2004, discovered ripples formed by water flowing across the surface of ancient Mars, but it was uncertain if that water ever pooled to form lakes or shallow seas. The Curiosity rover discovered evidence for long-lived ancient lakes in 2014, and now 10 years later Curiosity has discovered ancient lakes that were free of ice, offering an important insight into the planet’s early climate.
Since the lakes were warm enough to not freeze over, could there have been any microbes swimming in them? We don’t know, but it’s an exciting possibility to contemplate!
Bottom line: At least some ancient lakes on Mars were ice-free. NASA’s Curiosity rover discovered evidence for small wind-blown ripples on the former lakes in Gale crater.
Source: Wave ripples formed in ancient, ice-free lakes in Gale crater, Mars
Read more: Ancient Mars lake was larger than any on Earth
Read more: Did this Mars rock once lie along an ancient lakeshore?
The post Lakes on Mars had ripples! They must have been ice-free first appeared on EarthSky.
from EarthSky https://ift.tt/JfA35XV
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