DescripcióSlope Streaks in Acheron Fossae on Mars.jpg
English: What creates these picturesque dark streaks on Mars? No one knows for sure. A leading hypothesis is that streaks like these are caused by fine grained sand sliding down the banks of troughs and craters. Pictured above, dark sand appears to have flowed hundreds of meters down the slopes of Acheron Fossae. The sand appears to flow like a liquid around boulders, and, for some reason, lightens significantly over time. This sand flow process is one of several which can rapidly change the surface of Mars, with other processes including dust devils, dust storms, and the freezing and melting of areas of ice. Acheron Fossae is a 700 kilometre long trough in the Diacria quadrangle of Mars.
The above image was taken by the HiRise camera on board the Mars Reconnaissance Orbiter which has been orbiting Mars since 2006. Local Mars time: 3:25 PM. Latitude (centered): 37.3 °. Longitude (East): 229.1 °
Range to target site: 290.4 km. Original image scale range: 58.1 cm/pixel (with 2 x 2 binning) so objects ~174 cm across are resolved. Map projected scale: 50 cm/pixel and north is up. Map projection: EQUIRECTANGULAR. Emission angle: 0.9 °. Phase angle: 51.8 °. Solar incidence angle:. 51 °, with the Sun about 39 ° above the horizon . Solar longitude: 144.7 °, Northern Summer.
El lloc web de la NASA disposa d'un gran nombre d'imatges de l'Agència Espacial Russa, o soviètica, i d'altres agències no nord-americanes. Aquestes imatges no són necessàriament en el domini públic.
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