Publication Date:
2015-03-13
Description:
Detection of sodium-salt-rich ice grains emitted from the plume of the Saturnian moon Enceladus suggests that the grains formed as frozen droplets from a liquid water reservoir that is, or has been, in contact with rock. Gravitational field measurements suggest a regional south polar subsurface ocean of about 10 kilometres thickness located beneath an ice crust 30 to 40 kilometres thick. These findings imply rock-water interactions in regions surrounding the core of Enceladus. The resulting chemical 'footprints' are expected to be preserved in the liquid and subsequently transported upwards to the near-surface plume sources, where they eventually would be ejected and could be measured by a spacecraft. Here we report an analysis of silicon-rich, nanometre-sized dust particles (so-called stream particles) that stand out from the water-ice-dominated objects characteristic of Saturn. We interpret these grains as nanometre-sized SiO2 (silica) particles, initially embedded in icy grains emitted from Enceladus' subsurface waters and released by sputter erosion in Saturn's E ring. The composition and the limited size range (2 to 8 nanometres in radius) of stream particles indicate ongoing high-temperature (〉90 degrees C) hydrothermal reactions associated with global-scale geothermal activity that quickly transports hydrothermal products from the ocean floor at a depth of at least 40 kilometres up to the plume of Enceladus.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hsu, Hsiang-Wen -- Postberg, Frank -- Sekine, Yasuhito -- Shibuya, Takazo -- Kempf, Sascha -- Horanyi, Mihaly -- Juhasz, Antal -- Altobelli, Nicolas -- Suzuki, Katsuhiko -- Masaki, Yuka -- Kuwatani, Tatsu -- Tachibana, Shogo -- Sirono, Sin-iti -- Moragas-Klostermeyer, Georg -- Srama, Ralf -- England -- Nature. 2015 Mar 12;519(7542):207-10. doi: 10.1038/nature14262.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA. ; 1] Institut fur Geowissenschaften, Universitat Heidelberg, 69120 Heidelberg, Germany [2] Institut fur Raumfahrtsysteme, Universitat Stuttgart, 70569 Stuttgart, Germany. ; Department of Complexity Science and Engineering, University of Tokyo, Kashiwa 277-8561, Japan. ; Laboratory of Ocean-Earth Life Evolution Research, JAMSTEC, Yokosuka 237-0061, Japan. ; 1] Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA [2] Institute for Particle and Nuclear Physics, Wigner RCP, 1121 Budapest, Hungary. ; European Space Agency, ESAC, E-28691 Madrid, Spain. ; Research and Development Center for Submarine Resources, JAMSTEC, Yokosuka 237-0061, Japan. ; Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan. ; Department of Natural History Sciences, Hokkaido University, Sapporo 060-0810, Japan. ; Graduate School of Environmental Sciences, Nagoya University, Nagoya 464-8601, Japan. ; Institut fur Raumfahrtsysteme, Universitat Stuttgart, 70569 Stuttgart, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25762281" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
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Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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