robot spacecraft Galileo, in orbit around Jupiter since 1995, swooped past the dark moon in May. The resulting pictures were the highest resolution yet obtained for a Jovian moon: objects as small as 3 meters across are discernable. The strange landscapes pictured above show areas rich in bright sharp mounds about 100 meters tall. A likely formation hypothesis holds that these hills are the result of ejecta thrown billions of years ago during a violent impact. The lower inset region apparently has undergone an epoch of relatively high ice-erosion, where dark rock has filled in some of the inter-hill regions. NASA has recently cleared Galileo to continue swooping Jupiter's moons until 2003, when it will end its journey with a spectacular dive into Jupiter's atmosphere.
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture Of the Day
Publications with keywords: Jupiter - Callisto
Publications with words: Jupiter - Callisto