Mars Express kigger ind i Mars Grand Canyon

Den seneste billedudgivelse fra ESA's Mars Express tager os over to brud i Mars-skorpen, der udgør en del af det mægtige Valles Marineris-kløftsystem.

Valles Marineris skærer på tværs af Mars ligesom Grand Canyon skærer på tværs af USA, bortset fra at sidstnævnte er minimal i sammenligning. Med en længde på 4000 km, 200 km bred og op til 7 km dyb er Valles Marineris næsten ti gange længere, 20 gange bredere og fem gange dybere end Grand Canyon. Som det største canyonsystem i solsystemet ville det spænde over afstanden fra nordspidsen af ​​Norge til sydspidsen af ​​Sicilien.

Der er en anden stor forskel mellem de to:Mens Grand Canyon blev dannet, da Colorado-floden eroderede sten, menes Valles Marineris at være dannet gennem de tektoniske plader, der driver fra hinanden.

Billedet viser to skyttegrave (eller chasma), der udgør en del af det vestlige Valles Marineris. Til venstre (syd) er den 840 km lange Ius Chasma, og til højre (nord) er den 805 km lange Tithonium Chasma. Selvom disse billeder i høj opløsning viser utrolige overfladedetaljer, er det først, når vi ser på et højdekort, at vi indser, hvor spektakulært dyb chasmataen er - op til 7 km! Med sine 4809 m ville Alpernes højeste bjerg Mont Blanc blive dværg, hvis det blev sat inde i Tithonium Chasma.

På toppen af ​​Tithonium Chasma bringer en plet mørkt sand farvekontrast til billedet. Dette sand kan være kommet fra den nærliggende vulkanske region Tharsis.

Ved siden af ​​de mørke klitter ligger to lystonede høje (den ene skåret i to af den øverste billedkant). Disse "høje" ligner mere bjerge, der rejser sig mere end 3000 meter i højden. Their surfaces have been strongly eroded by Mars' strong winds, indicating that they are made of a weaker material than the surrounding rock.

Between the two mounds we see a series of smaller bumps, as shown in the second perspective view. Investigations by Mars Express have found water-bearing sulfate minerals in this region. This suggests that these bumps may have formed when liquid that once filled the chasma evaporated, although this theory is still hotly debated.

To the lower right of the mound that we see fully (upper right in the second perspective view), we can see parallel lines and debris piles that indicate a recent landslide. This is also visible as a large purple area in the topography image below. The landslide was caused by the collapse of the canyon wall on the right, and is likely to have occurred relatively recently because it has not been strongly eroded.

The gnarly floor of Ius Chasma is equally fascinating. As tectonic plates pulled apart, they appear to have caused jagged triangles of rock to form that look like a row of shark teeth. Over time, these rock formations have collapsed and eroded.

Exploring Mars

Mars Express has been orbiting the Red Planet since 2003, imaging Mars' surface, mapping its minerals, identifying the composition and circulation of its tenuous atmosphere, probing beneath its crust, and exploring how various phenomena interact in the Martian environment.

The mission's High Resolution Stereo Camera (HRSC), responsible for these new images, has revealed much about Mars' diverse surface features, with recent images showing everything from wind-sculpted ridges and grooves through impact craters and channels that once carried liquid water to volcanoes, tectonic faults, river channels and ancient lava pools. + Udforsk yderligere

Image:Layers and fractures in Ophir Chasma, Mars