Pacman Found on Moon of Saturn

NASA's Cassini spacecraft has taken a high resolution infrared photo of Mimas, a moon of Saturn, which shows hot regions in the shape of Pacman, the popular 1980s video game character, eating a dot, as was his habit in the game.

The photo was taken on Feb 13, 2009, when Cassini made its closest flyby of Mimas.

A previous image of Mimas, taken with visible light, shows that Mimas also looks like the Star Wars movies' Death Star.

Mimas has a huge crater that is known as Herschel Crater, after William Herschel, the astronomer who discovered the moon in 1789. Herschel Crater is about 80 miles across, one third the diameter of the Mimas itself.

NASA scientists think that the enormous amount of energy that must have been released when Herschel Crater was formed several billion years ago could have caused the Pacman-like temperature pattern.

The impact that would have caused the crater to form would have used about one seventh of Mimas' gravitational energy.

The opposite side of Mimas is covered with long, canyon-like depressions, known as chasmata, that might have been the result of shock waves following the impact.

Differences in surface texture would also have contributed to temperature differences on different parts of the moon's surface.

Mimas is made mostly of water ice.

Dense ice would conduct the sun's heat away from Mimas' surface, so areas underneath dense ice would remain cold throughout the day. Powdery ice would trap the sun's heat, and warm up the surface underneath it.

The impact that caused Herschel Crater to form could have melted ice and spread water across Mimas, which could have flash-frozen later, to form a hard surface.

Mimas is the closest of Saturn's major moons, orbiting a little over 115,000 miles from Saturn. One side of Mimas always faces Saturn.

The moon is covered with impact craters; Herschel is much larger than the other craters.

Mimas was named after a Titan in Greek mythology.