Methane mystery on Saturn’s moon rekindles search for life on other planets
Researchers struggle to explain suspicious amounts of methane on Enceladus while a new chapter opens in the debate around the source of Venus’s phosphine. Why is it so hard to decide what counts as a sign of life?
Last year, a team of scientists suggested that phosphine in Venus’s clouds could be a sign of life – a study that has now been contested by scientists proposing how volcanoes and atmospheric chemistry could have produced the compound.1 At the same time, a different study has discovered that there’s too much methane on Saturn’s moon Enceladus to come from simple geochemical processes.2 Instead, it might be produced by microbes living in hydrothermal vents deep under the moon’s icy surface.