Moons of Jupiter: A Tour

link to Jovian Satellite Factsheet
link to Galileo mission to Jupiter and its Moons
link to Galileo Moons and Rings page
link to Cassini Jupiter Flyby science page
link to  3-D stereo-atlas planet tour

IO:  In Greek mythology, a young woman seduced by Zeus, who then transformed her into a heifer to protect her from his jealous wife.  Also, the closest, largest moon of Jupiter.

Io: the most volcanically active body in the solar system.  Image from Voyager I, Marcy 4, 1979.

volcanic explosion:  June 28, 1996 eruption on Io, extending about 100 kilometers (about 60 miles) into space.  The blue color of the plume is consistent with the presence of sulfur dioxide gas and "snow" condensing from the gas as the plume expands and cools. see  caption

changing face of Io : HST images show the a 200-mile diameter large yellowish-white feature near the center of Io's disk (photo on the right).  Photo on the left was taken in March 1994 -- before the spot emerged.  Each image is a composite of frames taken at near-ultraviolet, violet, and yellow wavelengths.

notes: how many craters are seen on surface of Io? how does the level of volcanic activity compare with that of Earth?

link to Galileo Images of Io

link to Lunar and Planetary Lab Io page

Io factoids: recent Io news:
Europa: In Greek mythology, a mistress of Zeus to whom he appeared as a gentle white heifer. Zeus persuaded her to take a ride on his back, and then he carried her away across the sea.  Also, the second of Jupiter's large moons.

Europa: This moon is nearly the same size as Earth's moon.  It has an ice surface about 100 km (62 mi) thick.  The streaks on the surface indicate  that the crust has been fractured.  The lack of mountains or craters on Europa's bright limb is consistent with an ice surface.  In contrast to its icy neighbors, Ganymede and Callisto, Europa has few impact craters. One possible candidate is the small feature near the center of this image with radiating rays and a bright circular interior. The relative absence of features and low topography suggests the crust is young.

high resolution image: Highest-resolution view of Europa obtained by Voyager 2 in July 1979. Smallest features that are resolvable are about 2 kilometers across. Most of the geologic features that characterize Europa are visible. Enigmatic triple bands (long dark linear features) occur in the top half of the mosaic. Wedge-shaped bands occur near the anti-jove region (left center), and cycloidal ridges occur at southern latitudes (bottom). Linear ridges a few hundred meters high are seen near the terminator. Irregularly shaped patches of relatively dark material, known as mottled terrain, are seen in the central (or equatorial) areas. The south pole is near the bottom of the mosaic. This mosaic shows Europa in approximately natural color. (from

 southern hemisphere : good view of the variety of linear tectonic features visible in the southern hemisphere. Dark, wedge-shaped bands are
visible at upper left, narrow linear dark bands are present in most areas, and curvilinear cycloidal ridges are present in the bottom half of the
image. Three small impact craters are also visible, near the bottom, top right, and along the terminator near the top of the mosaic.  (from

link to  Europa Revealed: from the Astrobiology Web

link to Galileo Images of Europa

link to Lunar and Planetary Lab Europa page

recent Europa news:

Ganymede: In Greek mythology, a beautiful Trojan boy, son of Tros and Calirrhoe. Befriended by Zeus and made cupbearer to the Olympian gods.  Also, the third and largest of Jupiter's large moons.

Ganymede:  Voyager 1, 1979.

link to Galileo Images of Ganymede

link to Lunar and Planetary Lab Europa page

recent Ganymede news:

Callisto:  In Greek mythology, a nymph, follower of Artemis. Zeus wanted to woo her, and so disguised himself as Artemis and seduced her. To hide her from his jealous wife Hera, Zeus changed Callisto into a bear.  Also, the outermost of Jupiter's large moons and the only one of the four large moons not affected by tidal heating from Jupiter.

Callisto: Voyager 2 image, July 7, 1979.  Shows ancient, heavily cratered terrain.

Callisto: close-up: Voyager 2 image.

link to Galileo Images of Callisto

link to Lunar and Planetary Lab Callisto page

recent Callisto news:

Moons of Saturn

link to Lunar and Planetary Lab Saturnian Satellites page
link to Cassini Mission homepage


link to Lunar and Planetary Lab Titan page
link to Saturnian Satellites Fact Sheet

Moons of Uranus

link to Lunar and Planetary Lab Uranian Satellites page


link to Lunar and Planetary Lab Miranda and Ariel page
link to Uranian Satellites Fact Sheet

Moons of Neptune

link to Lunar and Planetary Lab Neptunian Satellites page


link to Lunar and Planetary Lab Triton page
link to Neptunian Satellites Fact Sheet