Closeup of an Io Volcano
4.08.1995

In 1979, one of NASA's Voyager spacecraft made a spectacular and unexpected discovery. Io, the innermost Galilean moon of Jupiter, was covered with volcanoes and some of them were erupting! In all, Voyager 1 observed nine volcanic eruptions during its encounter with the moon.

Io Full Face
29.10.1996

Io is a colorful place. The closest large moon of Jupiter, Io is the most volcanic moon in the Solar System with its surface being completely buried in volcanic lava every few thousand years.

Io Aurora
16.10.1998

Alluring aurora surrounding Io (eye-oh) appear as a ghostly glow while the volcanic moon orbits within Jupiter's dark shadow. Gas giant Jupiter is off to the right of this image, recorded in May by the robot Galileo spacecraft's solid state imaging camera from a distance of about 1.3 million kilometers.

Io's Sodium Cloud
28.04.1997

Io has its own cloud. Jupiter's most active moon is visible on the left of the above false-color photograph, with its left side illuminated by sunlight. But what is happening on Io's right side? Here a plume of gas from the active volcano Prometheus also reflects sunlight.

Erupting Volcanoes on Io
5.08.1996

Jupiter's moon Io has active volcanoes. The Voyager spacecraft caught several erupting when they passed the energetic moon in 1979. In the above picture, several of Io's volcanoes are visible and one is seen actually erupting.

Io Rotating
31.12.1996

Are any volcanoes on Io currently erupting? To help answer this, scientists instructed the robot spacecraft Galileo to take hourly pictures of this moon of Jupiter prior to its most recent encounter. The most obvious changes in Io are due to the changing amount of sunlight reflected from the moon to the spacecraft.

Io in True Color
15.07.2001

The strangest moon in the Solar System is bright yellow. This picture, showing Io's true colors, was taken in 1999 July by the Galileo spacecraft currently orbiting Jupiter. Io's colors derive from sulfur and molten silicate rock. The unusual surface of Io is kept very young by its system of active volcanoes.

Io in True Color
2.05.2004

The strangest moon in the Solar System is bright yellow. This picture, showing Io's true colors, was taken in 1999 July by the Galileo spacecraft that orbited Jupiter from 1995 to 2003. Io's colors derive from sulfur and molten silicate rock.

A Continuous Eruption on Jupiters Moon Io
6.06.2000

A volcano on Jupiter's moon Io has been photographed recently during an ongoing eruption. Hot glowing lava is visible on the left on this representative-color image. A glowing landscape of plateaus and valleys covered in sulfur and silicate rock surrounds the active volcano.

Jupiter, Io, and Shadow
7.12.2002

Pictured above is the innermost of Jupiter's Galilean satellites, Io, superposed in front of the gas giant planet. To the left of Io is a dark spot that is Io's own shadow. A solar eclipse would be seen from within the shadow spot on Jupiter.