Original URL: http://www.theregister.co.uk/2014/02/13/ganymede_map_helps_reveal_satellites_secrets/

Ganymede map helps reveal satellite's secrets

Old images of an ancient moon yield new cartography

By Richard Chirgwin

Posted in Science, 13th February 2014 04:54 GMT

“Google Ganymede” can only be a matter of time: a group of scientists has produced the first geological map of Ganymede, the moon of Jupiter. Ganymede map joins Earth's moon, and other Jovian moons Io and Callisto, in the select group of planetary satellites for which such maps have been produced.

The map is based on images from the Voyager and Galileo missions, and was put together by a team lead by Johns Hopkins Applied Physics Laboratory's Wes Patterson and Wheaton College's Geoffrey Collins. Voyager's images date back to 1979, while the Galileo images were taken between 1995 and 2003.

Paterson is quoted by the university as saying “By mapping all of Ganymede’s surface, we can more accurately address scientific questions regarding the formation and evolution of this truly unique moon”.

The 5,262-km-diameter Ganymede is interesting to scientists in a variety of ways: it has its own magnetosphere (the only satellite in the solar system known to possess one), and its complex geology shows two distinct ages in its formation. The oldest terrain types are dark and highly cratered, while younger regions are “marked with an extensive array of grooves and ridges”, the scientists say.

“These features record evidence of Ganymede’s internal evolution, its dynamical interactions with the other Galilean satellites, and the evolution of the small bodies that have impacted Ganymede’s surface,” they note.

The map is hosted by the US Geological Survey, here. ®