ALMA Reveals Jupiter’s Moon Io has been Volcanically Active for Billions of Years

Jupiter’s moon Io is the most volcanically active place in the solar system. During its 1.8-day orbit, this moon is gravitationally squeezed by Jupiter, leading to volcanic eruptions larger than any on Earth today.

Io, Europa, and Ganymede are in an orbital configuration known as a Laplace resonance: for every orbit of Ganymede (the farthest of the three from Jupiter), Europa completes exactly two orbits, and Io completes exactly four. In this configuration, the moons pull on each other gravitationally in such a way that they are forced into elliptical, rather than round, orbits. Such orbits allow Jupiter’s gravity to heat the moons’ interiors, causing Io’s volcanism and adding heat to the subsurface liquid ocean on icy Europa.

How long has Io been experiencing volcanic upheaval? In other words, how long have Jupiter’s moons been in this configuration?

To discover the answer, researchers utilized the ALMA (Atacama Large Millimeter/submillimeter Array) telescope in Chile—a telescope that is itself surrounded by volcanoes—to measure sulfur isotopes on Io.

Read the full press release from Caltech.

Print Friendly, PDF & Email

About the Author:
Jill Malusky is the News and Public Information Manager for NRAO. Prior to this, she served as Public Information Officer for the Green Bank Observatory. Before joining the SciComm universe she held leadership roles as a director in art and history museums, and as a consultant and contractor in communications and design for cultural institutions across the US. She earned her bachelor of arts in film from Wright State University (Dayton, Ohio) and her masters in anthropology (University of Manchester, England.) With the news team, Jill uses an authentic and inclusive voice to share stories about NRAO’s science and staff through a variety of press products, print and digital content, and collaborations with journalists and media creators.

More News From Atacama Large Millimeter/submillimeter Array

More News Related to ALMA