California Institute of Technology | 2015 Oct 27
[img3="The puzzling, fascinating surface of Jupiter's icy moon Europa looms large in images taken by NASA's Galileo spacecraft. (Credit: NASA/JPL-Caltech/SETI Institute)"]http://www.jpl.nasa.gov/spaceimages/ima ... 048_ip.jpg[/img3][hr][/hr]Jupiter’s moon Europa is believed to possess a large salty ocean beneath its icy exterior, and that ocean, scientists say, has the potential to harbor life. Indeed, a mission recently suggested by NASA would visit the icy moon’s surface to search for compounds that might be indicative of life. But where is the best place to look? New research by Caltech graduate student Patrick Fischer; Mike Brown, the Richard and Barbara Rosenberg Professor and Professor of Planetary Astronomy; and Kevin Hand, an astrobiologist and planetary scientist at JPL, suggests that it might be within the scarred, jumbled areas that make up Europa’s so-called “chaos terrain.”
“We have known for a long time that Europa’s fresh icy surface, which is covered with cracks and ridges and transform faults, is the external signature of a vast internal salty ocean,” Brown says. The areas of chaos terrain show signatures of vast ice plates that have broken apart, shifted position, and been refrozen. These regions are of particular interest, because water from the oceans below may have risen to the surface through the cracks and left deposits there.
“Directly sampling Europa’s ocean represents a major technological challenge and is likely far in the future,” Fischer says. “But if we can sample deposits left behind in the chaos areas, it could reveal much about the composition and dynamics of the ocean below.” That ocean is thought to be as deep as 100 kilometers. ...
In a search for such deposits, the researchers took a new look at data from observations made in 2011 at the W. M. Keck Observatory in Hawaii using the OSIRIS spectrograph. Spectrographs break down light into its component parts and then measure their frequencies. Each chemical element has unique light-absorbing characteristics, called spectral or absorption bands. The spectral patterns resulting from light absorption at particular wavelengths can be used to identify the chemical composition of Europa's surface minerals by observing reflected sunlight. ...
Spatially Resolved Spectroscopy of Europa: The Distinct Spectrum of Large-scale Chaos
- Patrick D. Fischer, Michael E. Brown, Kevin P. Hand
arXiv.org > astro-ph > arXiv:1510.07372 > 26 Oct 2015
http://asterisk.apod.com/viewtopic.php?t=30854
