American scientists have measured two isotopes of sulfur in the atmosphere of Jupiter's moon Io, indicating that volcanic activity has been present on this moon for billions of years since its formation. The findings were published in the journal Science on the 18th.
Io: A Volcanically Active World
Io, a moon of Jupiter, stands out as the most volcanically active body in the solar system, with eruptions spewing plumes of sulfur compounds. Astronomers attribute this phenomenon to tidal heating, but whether this activity persists indefinitely or if Io has experienced periods of calm remains uncertain.
In a recent study led by Katherine de Kleer and her colleagues at Caltech, researchers analyzed the ratio of two sulfur isotopes in Io's atmosphere to unveil its volcanic history.
The team explains that Io continuously emits both isotopes as volcanic gases. As Io orbits Jupiter, its upper atmosphere, rich in lighter sulfur atoms, escapes into space, altering the isotopic ratio.
Utilizing observations from the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, the researchers measured the isotopic ratio in Io's atmosphere. Their findings suggest that Io's volcanic activity has persisted for 2.5 to 4 billion years.
According to Lionel Wilson from Lancaster University, if Io has been erupting for billions of years, it implies that its deeper geological layers have undergone multiple recycling events. Scientists can sample erupting materials to gain insights into Io's deeper composition, such as the chemical makeup of its mantle.
