Feb. 26, 2012 - Outermost of Jupiter's four Galilean satellites: This photo of Callisto, outermost of Jupiter's four Galilean satellites was taken a few minutes after midnight (RSt) Feb 26, by Voyager 1. The distance of Gallisto was 4.98 million mile. The hemispher in this picture shows a fairly uniform surface dotted with brighter spots that are up to several hundred kilometers across.

- Image ID: E130RC

Feb. 26, 2012 - Outermost of Jupiter's four Galilean satellites: This photo of Callisto, outermost of Jupiter's four Galilean satellites was taken a few minutes after midnight (RSt) Feb 26, by Voyager 1. The distance of Gallisto was 4.98 million mile. The hemispher in this picture shows a fairly uniform surface dotted with brighter spots that are up to several hundred kilometers across.

Keystone Press / Alamy Stock Photo

Image ID: E130RC