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Voyager 1 View of Callisto Main Content
NASA Center: Jet Propulsion Laboratory
Image # : PIA-02253
Date : 03/06/1979

Title

Voyager 1 View of Callisto

Full Description

Voyager 1 took this picture of Callisto during Voyager's approach to Jupiter's outer large satellite in 1979. Both Galileo and Marius discovered Callisto in 1610. In Greek mythology, Callisto was a nymph loved by Zeus and thus hated by Hera. Hera turned her into a bear, which Zeus placed in the heavens as the constellation Ursa Major. Voyager was 350,000 kilometers from Callisto and took this picture that shows features about seven kilometers wide across the surface. Callisto is a little smaller than Ganymede (Callisto is about the size of Mercury) and it seems that it is composed of a mixture of ice and rock (about 40 percent ice and 60 percent rock and iron). The darker color of Callisto (about half as reflective as Ganymede but still twice as bright as the Moon) implies that the upper surface is "dirty ice" or water- rich rock frozen on Callisto's cold surface (approximately -243 Fahrenheit degrees at the equator). Callisto's atmosphere is mostly carbon dioxide. Far more craters appear on the surface of Callisto than on the surface of Ganymede, leading scientists to believe that Callisto is the oldest of the Galilean satellites. Callisto could date back as far as four billion years ago and has remained relatively unchanged in the history of space.

Keywords

Callisto Jupiter Voyager Ursa Major JPL Grand Tour

Subject Category

Voyager-Galileo, Jupiters Moons,

Reference Numbers

  • Center: JPL
  • Center Number: PIA-02253
  • GRIN DataBase Number: GPN-2003-000004

Source Information

  • Creator/Photographer: NASA
  • Original Source: Digital

Image Information ( Copyright Notification )

ResolutionFormatWidth
(Pixels)		Height
(Pixels)		Size
(KBytes)
Thumbnail JPEG 100 100 8
Small JPEG 800 800 190
Medium JPEG 1667 1667 512
Large JPEG 3333 3333 1,384

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