Jupiter’s moon Io may have been torn by violent volcanic eruptions for billions of years – iPon

Jupiter’s moon Io has been continuously shaped by volcanic activity for billions of years, which, according to a new study, may have been going on since the beginning of the entire 4.57 billion-year history of the Solar System. THE Science The results, published in the April 18 issue, may have implications for the search for extraterrestrial life and for understanding volcanically active moons and planets, including Earth.

Io is the most volcanically active place in the Solar System, with hundreds of volcanoes on its surface. This makes it difficult to study the moon’s past. The surface of the moon is constantly shaped by the liquid lava and ash that erupts and settles from volcanoes, thus covering up the physical evidence of its past. The volcanic activity is based on the fact that Io’s orbit around Jupiter is synchronized with the orbits of two neighboring moons, Europa and Ganymede. Due to the gravitational interactions between them, Io’s orbit has become elliptical, and the interior of the moon is compressed from time to time, causing friction and heating.

When Io’s volcanoes erupt, they shoot sulfur-rich gases into the atmosphere. Researchers were able to use this sulfur as a tracer to study Io’s long-term evolution, explains Katherine de Kleer, a planetary scientist at CalTech in Pasadena and co-author of the study.

In the Solar System, the ratio between the two sulfur isotopes — sulfur-32 and the slightly heavier sulfur-34 — is relatively constant, says de Kleer. Using the Chilean radio telescope ALMA, the researcher and his colleagues measured the sulfur emissions of Io’s atmosphere and calculated the ratio between the two isotopes.

Their observations revealed that Io has lost 94-99% of the sulfur it originally had. In the upper atmosphere, the ratio of sulfur isotopes shifts slightly toward the lighter version, and these sulfur-32-rich gases leave the atmosphere at a rate of about a ton per second, de Kleer says. Over billions of years, this has led to Io’s overall sulfur composition becoming heavier. Extrapolating from the current rate of loss of lighter sulfur, the researchers calculated that volcanoes may have been active for most of Io’s history.

The research also confirms models that Io, Europa and Ganymede have been performing the same orbital dance since the birth of the Solar System or shortly thereafter as they do today. This raises the possibility that similar warming effects may have been occurring under the ice crust in Europe for a long time, says de Kleer. Europa is a very promising candidate in the Solar System for finding life outside of Earth, and if this effect has persisted for billions of years, it further increases the likelihood that life could indeed have developed on the moon.

Io is extremely hot, with lava much hotter than what is currently typical on Earth, but we think this magma composition dominated early Earth history, when large lava flows formed in short periods of time, says de Kleer. The volcanism of Io can thus offer a window into the early history of the Earth.