Sulfuric Acid on Europa and the Radiolytic Sulfur Cycle
R. W. Carlson,
1*
R. E. Johnson,
2
M. S. Anderson
1
A comparison of laboratory spectra with Galileo data
indicates that hydrated sulfuric acid is present and is a major
component of Europa's surface. In addition, this moon's visually dark
surface material, which spatially correlates with the sulfuric acid
concentration, is identified as radiolytically altered sulfur polymers.
Radiolysis of the surface by magnetospheric plasma bombardment
continuously cycles sulfur between three forms: sulfuric acid, sulfur
dioxide, and sulfur polymers, with sulfuric acid being about 50 times
as abundant as the other forms. Enhanced sulfuric acid concentrations are found in Europa's geologically young terrains, suggesting that
low-temperature, liquid sulfuric acid may influence geological processes.
1 Jet Propulsion Laboratory, California
Institute of Technology, Pasadena, CA 91109, USA.
2 Engineering Physics, School of Engineering and
Applied Sciences, University of Virginia, Charlottesville, VA
22903-2442, USA.
*
To whom correspondence should be addressed. E-mail:
rcarlson{at}lively.jpl.nasa.gov
