... Dark Sand Cascades on Mars . ... Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. ... NGC 1365: Majestic Spiral with Supernova . ... A cosmic grain of sand left the long and colorful trail across this all-sky view. ... As the total phase of last week's solar eclipse came to an end, sunlight streaming past the edge of the Moon created the fleeting appearance of a glistening diamond ring in the sky. ...