As it passed the orbit of Mars, the spacecraft picked up a pair of craters in the planet’s surface that are part of the Valles Marineris, a system of canyons known as the Grand Canyon of Mars.
However, the Martian Grand Canyon makes the Earth version look like an ant canyon.
Approximately 4,000 kilometers (2,485 miles) long and 200 miles wide, Valles Marineris is about 10 times longer and 20 times wider than the wide valley system found in North America. Earth doesn’t have anything close to comparing it to Valles Marineris, which makes this feature hugely intriguing to planetary scientists.
The tomograms by Mars Express include two-part sections, Ius on the left and Tithonium on the right. Careful study of the details of these amazing natural structures can help scientists understand Mars’ geology and geological history.
For example, Mars now appears to be tectonically extinct, as its crust has merged into one separate layer that encases the planet’s interior. This is in contrast to Earth, where its crust is divided into plates that can move around it, with a whole host of consequences.
Scientists believe that Valles Marineris formed again when Mars had plate tectonics. Recent research has suggested that the valley system may have formed as a result of fault widening between the plates, long ago. This makes Valles Marineris really fun.
Images from Mars Express make the valley appear relatively shallow, but the Chasmas are incredibly large; The full resolution version is about 25 kilometers per pixel. Ius Chasma stretches for a total length of 840 km, and Tithonium Chasma is 805 km long.
The probe is also equipped with 3D imaging capabilities, which reveal, in this image, that the canyon reaches as deep as possible – about 7 kilometers, five times deeper than the Grand Canyon.
There are several notable features that the images reveal in the two spaces. Within Ius, a row of jagged mountains likely formed when the two tectonic plates separated. As it was some time ago, these mountains were greatly eroded.
Tethonium is partially colored in darker tones in the upper part of the image. This may have come from the nearby volcanic region of Tharsis to the west of chasma. Paler mounds arise from within this dark sand; These are actually mountains with a height of more than 3 kilometers.
However, the mountaintops have been washed away by erosion. This indicates that the material the mountain is made of is weaker and weaker than the surrounding rock.
This rock is not impregnable either. In the lower right of the more visible mountains, features suggest a recent landslide of the valley wall to the right.
Interestingly, Mars Express has detected sulfate-bearing minerals in some traits within Tithonium Chasma. This has been interpreted as evidence that Chasma was (at least partially) filled with water.
The evidence is far from conclusive, but recent discoveries of hydrogen at Chasma suggest that much of the water may be bound to minerals below the surface.
As with most Mars science, it is difficult to draw conclusions with any certainty, because we are forced – for the moment, at least – to study it from a distance. But identifying areas of interest can help plan for future Mars missions, both manned and unmanned; Sending a rover to Valles Marineris is sure to help scientists answer some of the burning questions that have arisen.
Pictures like this are scientifically useful because they help formulate and sometimes answer these questions. But they’re also amazingly gorgeous.
The photos have been published on the ESA website.