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Habitability in High Radiation Environments: The Case for Gaia at Europa

Research by Dr. John F. Cooper, Space Physics Data Facility, NASA Goddard Space Flight Center

Input of iogenic sulfur from the Jovian magnetosphere.
Input of iogenic sulfur from the Jovian magnetosphere.

Research by John F. Cooper at NASA Goddard Space Flight Center et al theorize that icy satellites with significant heat, irradiation and subsurface water sources may provide common abodes for life throughout the universe. Europa is the most accessible icy body to test this theory, which may also apply to Snowball Earth intervals of global glaciation associated with the rise of atmospheric oxygen on Earth.

Europa Global Views in Natural and Enhanced Colors
Europa Global Views in Natural and Enhanced Colors

This work expands the work of Chyba, Phillips, and Hand (2000-2001), and early work of Cooper et al. (Icarus, Jan. 2001), that radiolytic production of oxidants and simple hydrocarbons on Europa's icy surface could support evolution and survival of life within a Europan subsurface ocean. Europa's surface and geologic structures related to convection in the ice crust, tidal heating, and the underlying ocean. The effect of the brines on convection may be analogous to thermahaline circulation in the terrestrial oceans.

The detected hydrated sulfates (including briny salts and sulfuric acid hydrates) on Europa's surface can be attributed to input of iogenic sulfur from the Jovian magnetosphere and to radiolytic processing driven by extremely high energy fluxes of magnetospheric electrons and protons, and this could make a critical contribution to astrobiological habitability within Europa. Further Europa exploration may reveal the means by which how life could have survived such episodes on Earth and evolved on icy worlds and moons elsewhere in the universe.

Significance to Solar System Exploration

Various Landscapes and Features on Europa
Various Landscapes and Features on Europa

Europa may have a tell-tale beating heart, and future missions such as those utilizing high power ion propulsion and science instrument technologies proposed in the Prometheus Program would need to survive, look through, and exploit the local magnetospheric, ionospheric, and atmospheric environments to sense its physical, chemical, and electromagnetic presence.


Gaia theory could apply if material observed on the surface of Europa directly originated from or was composed of biological compounds with sufficient abundance to affect geologic processes. Other essential requirements are an oxidizing atmospheric environment at the surface, where oxidants like molecular oxygen are produced by radiation processes (mediated by photosynthetic chemistry on Earth but more directly produced by radiolysis on Europa), reservoirs of liquid water and hydrocarbons on or below the surface, other reduced materials in the interior, and the geologic processes driving chemical exchange between the chemically oxidized surface and reduced interior environments.

Last Updated: 21 January 2014

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Last Updated: 21 Jan 2014