Are Saturn's rings transparent? The Cassini spacecraft that recently entered orbit around Saturn has confirmed that some of Saturn's rings are more transparent than others. Pictured above, Saturn's main A, B, and C rings can be seen, top to bottom, superposed against the gas giant planet. Although the B-ring across the top is opaque, Saturn's cloud tops can be clearly seen through the lower C-ring. The translucent nature of the C-ring likely indicates that it is less densely populated with ring particles than the B-ring. The above image was taken on July 30 while Cassini was over 7 million kilometers from Saturn.

What's different about this Moon? It's the terminators. In the featured image, you can't directly see any terminator -- the line that divides the light of day from the dark of night. That's because the image is a digital composite of 29 near-terminator lunar strips. Terminator regions show the longest and most prominent shadows -- shadows which, by their contrast and length, allow a flat photograph to appear three-dimensional. The original images and data were taken near the Moon by NASA's Lunar Reconnaissance Orbiter. Many of the Moon's craters stand out because of the shadows they all cast to the right. The image shows in graphic detail that the darker regions known as maria are not just darker than the rest of the Moon -- they are flatter. Dial-A-Moon: Find the phase of the Moon on your birthday.