Explanation: Orbiting above the lunar nearside on August 21, the Lunar Reconnaissance Orbiter turned to look back on a bright, Full Earth. As anticipated its Narrow Angle Camera scanned this sharp view of our fair planet, catching the shadow of the Moon racing along a path across the United States at about 1,500 miles per hour. In fact, the dark lunar shadow is centered over Hopkinsville, Kentucky at 1:25:30 Central Daylight Time. From there, the New Moon blocked the Sun high in clear skies for about 2 minutes and 40 seconds in a total solar eclipse.
Explanation: What was happening in the sky during last week’s total solar eclipse? This featured little-planet, all-sky, double time-lapse, digitally-fused composite captured celestial action during both night and day from a single location. In this 360×180 panorama, north and south are at the image bottom and top, while east and west are at the left and right edges, respectively. During four hours the night before the eclipse, star trails were captured circling the north celestial pole (bottom) as the Earth spun. During the day of the total eclipse, the Sun was captured every fifteen minutes from sunrise to sunset (top), sometimes in partial eclipse. All of these images were then digitally merged onto a single image taken exactly during the total solar eclipse. Then, the Sun’s bright corona could be seen flaring around the dark new Moon (upper left), while Venus simultaneously became easily visible (top). The tree in the middle, below the camera, is a Douglas fir. The images were taken with care and planning at Magone Lake in Oregon, USA.
Explanation: Why is Saturn partly blue? The featured picture of Saturn approximates what a human would see if hovering close to the giant ringed world. The image was taken in 2006 March by the robot Cassini spacecraft now orbiting Saturn. Here Saturn’s majestic rings appear directly only as a thin vertical line. The rings show their complex structure in the dark shadows they create on the image left. Saturn’s fountain moon Enceladus, only about 500 kilometers across, is seen as the bump in the plane of the rings. The northern hemisphere of Saturn can appear partly blue for the same reason that Earth’s skies can appear blue — molecules in the cloudless portions of both planet’s atmospheres are better at scattering blue light than red. When looking deep into Saturn’s clouds, however, the natural gold hue of Saturn’s clouds becomes dominant. It is not known why southern Saturn does not show the same blue hue — one hypothesis holds that clouds are higher there. It is also not known why Saturn’s clouds are colored gold. Next month, Cassini will end its mission with a final dramatic dive into Saturn’s atmosphere.
A Fleeting Double Eclipse of the Sun Image Credit & Copyright: Simon Tang
Explanation: Last week, for a fraction of a second, the Sun was eclipsed twice. One week ago today, many people in North America were treated to a standard, single, partial solar eclipse. Fewer people, all congregated along a narrow path, experienced the eerie daytime darkness of a total solar eclipse. A dedicated few with fast enough camera equipment, however, were able to capture a double eclipse — a simultaneous partial eclipse of the Sun by both the Moon and the International Space Station (ISS). The Earth-orbiting ISS crossed the Sun in less than a second, but to keep the ISS from appearing blurry, exposure times must be less than 1/1000th of a second. The featured image composite captured the ISS multiple times in succession as it zipped across the face of the Sun. The picture was taken in a specific color emitted by hydrogen which highlights the Sun’s chromosphere, a layer hotter and higher up than the usually photographed photosphere.