Astronomy Picture of the Day . ... In 2009, during Saturn's last equinox, Saturn's thin rings threw almost no shadows onto Saturn, since the ring plane pointed directly toward the Sun. NGC 7635: The Bubble Nebula . ... One solar day on a planet is the length of time from noon to noon. ... The Comet Hartley 2 Cruise . ... Early last November, small but active Comet Hartley 2 (103/P Hartley) became the fifth comet imaged close-up by a spacecraft from planet Earth. ... Comet and CME on the Sun . ...