January 18, 2013
Mars Express Orbiter Snaps Image Of River-Like Formation On Surface Below
Lee Rannals for redOrbit.com — Your Universe Online
The European Space Agency's (ESA) Mars Express has offered up a high-resolution photo of a river-like structure on Mars. The spacecraft used its high-resolution stereo camera last year to snap an image of Reull Vallis on the Red Planet.
Reull Vallis is a river-like structure believed to have formed when running water flowed in the distant martian past.
The ancient river bed cuts a steep-sided channel through the Promethei Terra Highlands before it runs towards the floor of the Hellas basin.
ESA said that the structure stretches for almost a thousand miles across the martian landscape, and is flanked by a number of tributaries. In fact, one of the tributaries can be clearly seen cutting into the main valley towards the upper north side, the space agency said.
Mars Express' new images show a region of Reull Vallis where the channel is over 4 miles wide and almost a thousand feet deep.
According to ESA, the sides of Reull Vallis are sharp and steep in the images taken by Mars Express, and show parallel longitudinal features covering the floor of the channel.
"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 ESA wrote.
It said the structures formed after it was carved by liquid water during the Hesperian period, which is a time frame on Mars believed to have ended between 3.5 billion and 1.8 billion years ago.
Similar structures can be found in other surrounding craters on the Red Planet, which are believed to be rich in ice.
The tributary intersecting the main channel appears to be part of a forking of the main valley into two branches further upstream before merging back into a single main valley, according to ESA.
In the right part of the Mars Express full image, you can see the Promethei Terra Highlands with their high and soft-rounded mountains, jutting out 8,200 feet above the plains.
ESA said the region shows a resemblance to the morphology found in regions on Earth affected by glaciation.
"For example, we can see circular step-like structures on the inner walls of the sediment-filled crater in the foreground of the second perspective view," ESA said. "Planetary scientists think that these may represent former high water or glacial levels, before ice and water sublimated or evaporated away in stages at various times."
The space agency concluded that the morphology of this ancient river bed has experienced a diverse history, with analogies seen in glacial activity on Earth. These analogies help to allow planetary scientists to gain glimpses of a past on the Red Planet, which could be similar to events on Earth today.