Ingredients for Life at Enceladus
In 2015 NASA's Cassini spacecraft made the deepest dive ever through a plume of gas and ice spraying from the south pole of Saturn's moon Enceladus. A Cassini science instrument "sniffed" the plume and detected hydrogen.
Hunter Waite, Ion and Neutral Mass Spectrometer Team Lead, Southwest Research Institute: "The instrument acts like a human nose, analyzing the smell, so to speak, or the composition of the gases in the environment. There was a significant amount of molecular hydrogen."
What makes this hydrogen important?
Waite: "The existence of molecular hydrogen, at least within the Earth's ocean system, is a... like a food source. It's candy for microbes. They eat the hydrogen; they turn it into methane. And with our findings we
were able to not only find out that there was H2 in the system, but to examine the chemistry that's associated with that process of taking hydrogen and turning it into methane."
Cassini previously discovered there's a salty, global ocean under Enceladus' icy crust and that hot ocean water was coming into contact with a rocky sea floor.
Waite: "Here on Earth the hydrothermal systems known as white smokers have water-rock interactions that lead to the release of molecular hydrogen in a similar fashion to, apparently, what's going on at Enceladus."
Life requires three primary ingredients:
Source of energy.
Right chemical ingredients.
Waite: "This is just the final step that shows that there's molecular hydrogen being produced by these same hydrothermal processes. And that molecular hydrogen has the chemical energy to support microbial systems in the interior ocean. It's not demonstration of finding life, but it shows the potential for the existence of life in this interior ocean."