New images reveal that vast and magnificent river once flowed on Mars

Kayakers might drool when they see 3D images released this week by the European Space Agency, as they reveal that a vast and magnificent river once flowed through what is known as the Reull Vallis region. The riverbed is 932 miles long and it’s believed to have been formed in the distant past, when rushing water carved a deep channel through the Promethei Terra Highlands in the Reull Vallis.

All images are courtesy of the European Space Agency

Borrowing from a popular 1992 fly-fishing movie, the ESA titled its Thursday website post: “Reull Vallis: A River Ran Through It.”

The new images, captured by the ESA’s Mars Express Team, show a portion of riverbed that measures 4.3 miles wide and nearly 1,000 feet deep.

They also reveal a tributary cutting into the main glacial-carved valley.

Of the Reull Vallis riverbed, the ESA states on its website:

This sinuous structure, which stretches for almost 1,500 km across the Martian landscape, is flanked by numerous tributaries, one of which can be clearly seen cutting in to the main valley towards the upper (north) side.

The sides of Reull Vallis are particularly sharp and steep in these images, with parallel longitudinal features covering the floor of the channel itself. These structures are believed to be caused by the passage of loose debris and ice during the ‘Amazonian’ period (which continues to this day) due to glacial flow along the channel.

The structures were formed long after it was originally carved by liquid water during the Hesperian period, which is believed to have ended between 3.5 billion and 1.8 billion years ago.

The Promethei Terra Highlands also feature rounded mountains that tower about 8,000 feet above the flat plains (see bottom image).

Reporting on the new images, Jesus Diaz of Gizmodo writes: “Together with all the data gathered by NASA and ESA robots and probes, it looks very much as though Mars suffered the same geological process we had here on our little blue planet. The researchers think that Reull Vallis is just like any glacial valley on Earth–like the one you can see in Yosemite, but without trees and tourists.”