Paul Johnson, scientist at the Jet Propulsion Laboratory, presented his research from his terrestrial laboratory designed to foretell the photochemistry of plantary ices.

Johnson_2011_2Paul's talk was well attended, clearly there is wide interest in the icy worlds of the outer solar system. Paul pointed out there is significant astrobiological interest due mostly to the evidence of liquid water beneath the surfaces of a number of Jovian and Saturnian satellites, especially Europa (a moon of Jupiter).

The surfaces of these bodies are illuminated by a variety of energetic sources including electrons and protons besides solar photons. These particles penetrate the surface and contribute to its chemistry.

Paul's work, funded by NASA, is intended to help answer the question, "If compounds of biological origin, such as amino acids, are present in the surface ice layer, can they be detected as evidence of biological activity?"

His review of his recent experiments at JPL strongly indicate that the survival of amino acids in ice near the surface of Europa is unlikely beyond tens of years—not geological time scales. Thus, if we are to expect to be able to detect amino acids with flybys or surface probes of Europa, there has to be a mechanism to constantly replenish them, for example continual deposits from space or from deep eruptions below the surface ice. 

Paul also encouraged students to apply for JPL summer interships for opportunities to contribute to projects such as his.

Thank you, Paul, for a great visit!