... South Polar Vortex Discovered on Titan . ... The above natural-color image shows the light-colored feature. The vortex was found on images taken last month when the robotic Cassini spacecraft flew by the unusual atmosphere-shrouded moon of Saturn. ... How fast is lightning? ... A Hole in Mars . ... The hole was discovered by chance on images of the dusty slopes of Mars' Pavonis Mons volcano taken by the HiRISE instrument aboard the robotic Mars Reconnaissance Orbiter currently circling Mars. ...