Ancient riverbeds suggest 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.

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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, The Guardian reported.

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 said, adding, "The only water source that could have sustained these rivers over such a vast area would have to be some kind of regional precipitation."