Jupiter’s moons have had active volcanoes since their inception – DW – 04/18/2024

Io, one of Jupiter’s moons, is the most volcanically active place in the solar system. Now new observations and measurements of isotopes present in its atmosphere show that it has been volcanically active throughout its life, about 4.5 billion years.

This is the main conclusion of two studies carried out by researchers from the California Institute of Technology (Caltech) in the US, for which they used the ALMA (Atacama Large Millimeter/submillimeter Array) telescope in Chile to observe gases in the atmosphere. Io’s tense atmosphere.

Io, Europa, and Ganymede, Jupiter’s other moons, are in an orbital configuration known as Laplace resonance: for every orbit of Ganymede (the farthest of the three from Jupiter), Europa makes exactly two orbits, and Io makes four.

In this configuration, satellites are gravitationally attracted in a way that forces them into elliptical rather than circular orbits. These orbits allow Jupiter’s gravity to heat the moons’ interiors, causing Io’s volcanism and adding heat to icy Europa’s underground liquid ocean.

To determine how long this has been the case, two new studies published in the journals Science and JGR-Planets measured, among other things, sulfur isotopes in Io’s atmosphere, determining that the moons have been engaged in this resonant dance for millennia. .millions of years.

Io, in eternal transformation

On Earth, traces of past events are found in fossils and craters, but Io – due to enormous volcanic activity – is in perpetual transformation, so its surface is only about a million years old, while the Moon itself is about 4.5 billion years old. old.

Hence the need to analyze, find out your past, the chemicals in its atmosphere.

The surface isn’t the only constantly changing feature: Io’s atmosphere is also being deflected into space at a rate of 1 ton per second due to collisions with charged particles in Jupiter’s magnetic field.

Life

Because the lightest sulfur isotope, sulfur-32, is most abundant in the upper atmosphere where these collisions occur, this isotope is disproportionately depleted compared to its heavier counterpart. Knowing how much light sulfur is missing could provide clues about how long the Moon has been volcanic.

From meteorites that are remnants of the early solar system, researchers determined that the solar system formed with a ratio of approximately 23 sulfur-32 atoms for every sulfur-34 atom. If Io had remained unchanged since its formation, it would have the same proportion today.

However, new measurements show that Io has lost between 94 and 99 percent of its original sulfur, meaning the Moon has been volcanically active for billions of years, losing sulfur into space all the while.

“Isotopes of sulfur and chlorine indicate that Io was volcanically active during the 4.57 billion year history of the solar system,” Science magazine summarizes.

Moreover, the duration of Io’s volcanism indicates that it entered orbital resonance with Europa and Ganymede shortly after its formation, confirming the model’s predictions over the past 20 years.

the(EFE, Science)