An article accepted for publication in “The Planetary Science Journal” reports a study on Io, one of Jupiter’s satellites, which specifically concerns its volcanoes. A team of researchers led by astronomer Imke de Pater of the University of Berkeley, USA, used the ALMA radio telescope to examine Io’s atmosphere as it enters and leaves Jupiter’s shadow, a phenomenon called an eclipse. That’s because during an eclipse it receives no sunlight, temperatures drop to the point that only the sulfur dioxide emitted by volcanoes is warm enough not to solidify. The conclusion is that between 30% and 40% of Io’s atmosphere is generated by volcanic activity. The researchers also found that some volcanoes emit not sulfur compounds but potassium chloride.