On March 2, 1979, a paper in Science ruminated on Io’s strange orbit. Because of the positions and orbits of neighboring moons, Io’s orbit is elliptical rather than circular.

ESA's Mars Express orbiter captured footage of the Mars' moon Deimos pass in front of Ganymede, Europa, Jupiter, Io and ...

Io, one of the most fascinating moons in our solar system, continues to mystify scientists with its intense volcanic activity and bizarre behavior. This moon, known for its towering volcanoes ...

At last count, Jupiter has 95 moons, but the four main ones — Ganymede, Callisto, Io and Europa — were discovered in 1610 by famed Italian astronomer Galileo Galilei.

kilometers (124 miles) of Io in February, and transmitted them to Earth during the following eight months. To approach Io, the spacecraft had to enter a region of hazardous radiation around Jupiter.