Friday, March 8, 2013

15 billion years ago a huge river flowed on Mars

New astonishing pictures by the European Space Agency have revealed a 1,500 km long and 7 km wide river that once ran across Mars. The agency's Mars Express imaged the striking upper part of the remnants of Reull Vallis river on Mars with its high-resolution stereo camera. 

Reull Vallis is believed to have formed when running water flowed in the distant martian past, cutting a channel through the Promethei Terra Highlands before running on towards the floor of the vast Hellas basin. This structure, which stretches for almost 1,500 km, is flanked by numerous tributaries. 

The images show a region of Reull Vallis where the channel is 7 km wide and 300 m deep. The sides of Reull Vallis are sharp and steep. These structures are believed to be caused by the passage of loose debris and ice during the “Amazonian” perio,d due to glacial flow along the channel. They were formed after it was originally carved by liquid water during the Hesperian period, which may have ended 3.5bn to 1.8bn years ago. 

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