New Image of Two of Saturn's Moons a Reminder of Their Differences

It's easy to forget how different siblings Mimas and Pandora -- two of Saturn's moons -- really are until photographed (relatively) side-by-side, as recently done by NASA's Cassini spacecraft.

Pandora is the smaller of the two: at just 50 miles (81 kilometers) across, the moon lacks sufficient gravity to pull itself into a round shape, unlike the larger Mimas. However, not to be overlooked, the runt may yet hold secrets in its elongated shape as to how it and other moons near Saturn's rings form, scientists say.

Mimas, on the other hand, measures some 246 miles (396 kilometers) across. In the picture, north on this moon is up and rotated 28 degrees to the right.

Thus far, 62 moons have been spied orbiting Saturn, though only 53 have been officially named. All told, they range from hard and rough to porous and coated in a fine blanket of ice particles. Some, including Rhea and Tethys, appear to have been formed billions of years ago, while others may have been part of larger bodies that broke up, scientists hypothesize.

Taken in blue light with Cassini's narrow-angle camera on May 14, 2013, the view was acquired at a distance of approximately 690,000 miles (1.1 million kilometers) from Mimas and has an image scale of 4 miles (7 kilometers) per pixel. Pandora was at a distance of 731,000 miles (1.2 million kilometers) when this image was taken, making the image scale on Pandora 4 miles (7 kilometers) per pixel.

The Cassini-Huygens mission represents a cooperative project by NASA, the European Space Agency (ESA) and the Italian Space Agency. Launched in 1997, the massive spacecraft is, according to the ESA, "designed to shed light on many of the unsolved mysteries arising from previous observations," including the origin of Saturn's rings and whether or not oceans exist on Titan, its largest moon.