Latest news with #NoachisTerra
Yahoo
6 days ago
- Science
- Yahoo
If aliens existed on Mars 3.7 billion years ago, they would have needed umbrellas
When you buy through links on our articles, Future and its syndication partners may earn a commission. Mars was a rainier, wetter place than planetary scientists previously thought, according to a new study of ancient, inverted river channels that span more than 9,000 miles (14,484 kilometers) in the Red Planet's southern Noachis Terra region. "Our work is a new piece of evidence that suggests that Mars was once a much more complex and active planet than it is now, which is such an exciting thing to be involved in," study leader Adam Losekoot of the U.K.'s Open University said in a statement. We've known Mars was once a wet planet ever since the Mariner 9 orbiter mission from the '70s photographed a surface covered in dried-up river channels. These channels were dated back to over 3.5 billion years ago. However, channels cut into the ground are not the only evidence for running water on Mars. When that water ran-off, or evaporated, it left sedimentary deposits. Sometimes we see these in craters that were once lakes filled with water: NASA's Curiosity rover is exploring Gale Crater, which has a central three-mile-tall (five-kilometer-tall) peak covered in sediment. Other times, these sediments were laid down on river beds. Over the eons, the sediments would have hardened, while the river channels and the land around them would have weathered and eroded away. That left the sediments, which are more resistant to erosion, sticking out as tall ridges. Geologists today call them fluvial sinuous ridges, or, more plainly, inverted channels. Now, Losekoot, who is a Ph.D. student, has led the discovery of a vast network of these channels in Noachis Terra based on images and data taken by the High Resolution Imaging Science Experiment (HiRISE) camera and the Context Camera on NASA's Mars Reconnaissance Orbiter, and the Mars Orbiter Laser Altimeter (MOLA) on the defunct Mars Global Surveyor mission. Previously, Noachis Terra had not been given due attention because it lacked the more classical river channels that form more obvious evidence of water. However, by mapping the network of inverted channels, Losekoot realized there was lots of evidence there had once been plentiful water in the region. "Studying Mars, particularly an under-explored region like Noachis Terra, is really exciting because it's an environment which has been largely unchanged for billions of years," said Losekoot. "It's a time capsule that records fundamental geological processes in a way that just isn't possible here on Earth." Some of the inverted channels appear as isolated segments that have survived the elements for billions of years. Others are more intact, forming systems that run for hundreds of miles and stand tens of yards tall. Such a widespread network of inverted channels does not suggest these channels were caused by flash floods, argues Losekoot. Rather, they seem to have formed in stable climatic conditions over a geologically significant period of time during the Noachian–Hesperian transition, which was the shift from one geological era into the next around 3.7 billion years ago. What's particularly intriguing is the most likely source of water to have formed these inverted channels is precipitation — be it rain, hail or snow. Indeed, given the size of the inverted channel network in Noachis Terra, this region of Mars may have experienced lots of rainy days in a warm and wet climate. RELATED STORIES — Carbon dioxide rivers? Ancient Mars liquid may not all have been water — Good news for life: Mars rivers flowed for long stretches long ago — Mars Had Big Rivers for Billions of Years It's more evidence that Mars was once more like Earth than the cold and barren desert it is today. Losekoot presented his findings at the Royal Astronomical Society's National Astronomy Meeting held at the University of Durham in the U.K., which ran between July 7 and July 11. Solve the daily Crossword
The Guardian
09-07-2025
- Science
- The Guardian
Discovery of ancient riverbeds suggests Mars once wetter than thought
Thousands of miles of ancient riverbeds have been discovered in the heavily cratered southern highlands of Mars, suggesting the red planet was once a far wetter world than scientists thought. Researchers spotted geological traces of nearly 10,000 miles (16,000km) of ancient watercourses, believed to be more than 3bn years old, in high resolution images of the rugged landscape captured by Mars orbiters. While some of the riverbeds are relatively short, others form networks that stretch for more than 100 miles. The widespread rivers were probably replenished by regular rain or snowfall in the region, researchers said. 'Water has been found on Mars countless times before, but what's really interesting here is that this is an area where for a long time we've thought there wasn't any evidence for water,' said Adam Losekoot, a PhD student at the Open University. 'What we found is that the area did have water and it was very distributed,' he added. 'The only water source that could have sustained these rivers over such a vast area would have to be some kind of regional precipitation.' The most dramatic signs of ancient water on Mars are the huge valley networks and canyons, thought to have been carved by water flowing across the terrain. But some areas of the planet have few valleys, leading scientists to question how wet the regions once were. One region that particularly puzzled researchers was Noachis Terra, or Land of Noah, one of the oldest landscapes on Mars. According to computer models of the ancient Martian climate, the region should have had substantial rain or snowfall, sculpting the terrain as the water flowed. Faced with a lack of evidence for ancient riverbeds, Losekoot and his colleagues turned to high-resolution images of Noachis Terra captured by instruments onboard Nasa's Mars Reconnaissance Orbiter (MRO) and Mars Global Surveyor. The images covered nearly 4m square miles of the planet's southern highlands, a land area much larger than Australia. The images revealed scores of geological features called fluvial sinuous ridges, also known as inverted channels. These form when tracks of sediment carried by ancient rivers harden over time, and are later exposed when the softer ground around them erodes. While some tracks are relatively narrow, others are more than a mile wide. 'We have lots of little ridge segments, and they are usually a couple of hundred metres wide and about 3.5km long, but there are some that are much, much larger than that,' Losekoot said. In one image from the MRO the pattern of fluvial sinuous ridges reveals a network of meandering tributaries and spots where the ancient riverbanks burst. Two rivers can be seen crossing into a crater, where water probably flowed in and filled it up before breaching the other side. The findings, to be presented on Thursday at the Royal Astronomical Society's national meeting in Durham, suggest an enduring presence of surface water in the Noachis Terra region of Mars about 3.7bn years ago. In its warmer, wetter past, the planet held vast bodies of water. Mars became the arid world we know today when its magnetic field waned, allowing the solar wind to erode its atmosphere and the water to escape into space. But some water may remain, unseen. Beyond Mars's polar ice caps, an international team reported in April, a vast reservoir of water could lie hidden deep beneath the Martian surface.
