Ανοιξιάτικη Τσουλήθρα. Spring Slide

Κατολισθήσεις σε μια παγωμένη πλαγιά στην επιφάνεια του Άρη, Μια λεπτομέρεια από την αρχική φωτογραφία του HiRISE.

Η Βόρεια Πολική περιοχή του Άρη καλύπτεται από στρώματα πάγου και σκόνης, που ονομάζονται "στρωσιγενείς πολικές αποθέσεις". Αυτό το μόνιμο πολικό κάλυμμα στην διάρκεια του χειμώνα καλύπτεται από ένα επιπλέον, εποχιακό αυτή την φορά, στρώμα πάγου διοξειδίου του άνθρακα. Όταν ο Ήλιος ανατέλλει την άνοιξη, οι απότομες πλαγιές αυτών των αποθέσεων είναι αυτές, που θερμαίνονται πρώτες. Ο πάγος διοξειδίου του άνθρακα εξαχνώνεται (μεταβαίνει κατ΄ευθείαν σε αέριο, από στερεό) και αποσταθεροποιεί χαλαρά κομμάτια φωλιασμένα στην απότομη πλαγιά. Υλικά, από τα χαλαρότερα στρώματα αποκόπτονται τότε και κατρακυλούν στην απότομη πλαγιά. Εδώ, μπορούμε να δούμε μια σκοτεινόχρωμη λωρίδα πλάτους περίπου ενός χιλιομέτρου, να σηματοδοτεί την πορεία αυτών των χαλαρών υλικών. Οι εικόνες του HiRISE συχνά έχουν πιάσει κατολισθήσεις την στιγμή που συμβαίνουν κατά την διάρκεια της άνοιξης, κατά μήκος της άκρης των πολικών αποθέσεων, σ' αυτή την περιοχή.

The North Polar region of Mars is capped with layers of water ice and dust, called the "polar layered deposits." This permanent polar cap is covered in the winter with a layer of seasonal carbon dioxide ice. When the sun rises in the spring, the steep edges of the polar layered deposits are the first to warm up. The dry ice sublimes (going directly from a solid to a gas) and destabilizes loose chunks perched on the steep cliff. Material from the weaker layers gets dislodged and cascades down the steep slope. Here, we can see a dark streak marking the path of that loose material, approximately 1 kilometer wide. HiRISE images often show avalanches in progress in the springtime along the edge of the polar layered deposits in this area. HiRISE is one of six instruments on NASA's Mars Reconnaissance Orbiter.

The University of Arizona, Tucson, operates the orbiter's HiRISE camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Science Mission Directorate, Washington. Image credit: NASA/JPL-Caltech/Univ. of Arizona

Lucien Clergue: Between Eros and Thanatos

Lucien Clergue made his name in the 1950s when, as a young photographer, he became close to both Jean Cocteau and Pablo Picasso both of whom supported him early in his career. He went on the establish himself as one of the most idiosyncratic and influential French photographers, combining a subtle artistic sensibility with the heat and sensuality of his native Provence.

Clergue's archive contains a vast array of imagery, but there are three strong themes that emerge female nudes, bullfighting, and Picasso and his circle. While the nudes have become iconic in the history of photography, all three subject matters are of significant, recurrent interest to Clergue, allowing him to express himself and his world.

Clergue's genius is to produce beautiful images that appeal on a sensual level, but that also engage the viewer intellectually. His photographs speak of the South of France: heat, sand, dust, art, sensuality and, in the case of bullfighting, life and death. They take us on a journey through Clergue's life and passions, while also revealing his deeper thoughts about the world and his place within it.

Clergue has said, "Three subjects are my main interest: death, life and a kind of no-man's-land in between. The death of the bulls at the bullfight, the nude female in true nature, landscape, seascape, sandscape are the essentials of my permanent research to find the beginnings of our world and ourselves."