Colloquium – Christopher Glein – The Enceladus-Exoplanet Connection: How Molecular Hydrogen on Ocean Worlds Could Support Life

Speaker: Christopher Glein (Southwest Research Institute)

Title: The Enceladus-Exoplanet Connection: How Molecular Hydrogen on Ocean Worlds Could Support Life

Abstract:

Saturn’s moon Enceladus has a subsurface ocean that erupts into space, forming a plume. We sampled the plume using the Cassini spacecraft and found that it contains materials that can fuel methane formation, namely CO₂ and H₂. Methane was also found. The amount of H₂ is far above the equilibrium abundance, indicating a source of chemical energy. This is the first time that evidence was found of a source of chemical energy from an extraterrestrial ocean. More recently, the James Webb Space Telescope detected CO₂, H₂, and CH₄ in the atmosphere of the sub-Neptune exoplanet K2-18 b. It was proposed that this temperate planet might have a liquid water ocean. If it does, I have found that methanogenesis would be favorable to drive metabolism there. This may represent the identification of a source of chemical energy far beyond our cosmic shoreline. These findings suggest the arrival of a new strategy in the search for habitable environments – follow the energy after water!

Host: Patrick R. LeClair