Post by glactus on Oct 13, 2009 6:41:15 GMT
An artist's rendering of an Europa probe
The global oceqan ocean on Jupiter's moon Europa contains about twice the liquid water of all the Earth's oceans combined. New research suggests that there may be plenty of oxygen available in that ocean to support life, a hundred times more oxygen than previously estimated.
Concentrations of oxygen would be great enough to support not only microorganisms, but also "macrofauna", that is, more complex animal-like organisms which have greater oxygen demands. The continual supply of oxygen could support roughly 3 billion kilograms of macrofauna, assuming similar oxygen demands to terrestrial fish.
The chances for life there have been uncertain, because Europa's ocean lies beneath several miles of ice, which separates it from the production of oxygen at the surface by energetic charged particles (similar to cosmic rays). Without oxygen, life could conceivably exist at hot springs in the ocean floor using exotic metabolic chemistries, based on sulfur or the production of methane. However, it is not certain whether the ocean floor actually would provide the conditions for such life.
Therefore a key question has been whether enough oxygen reaches the ocean to support the oxygen-based metabolic process that is most familiar to us. An answer comes from considering the young age of Europa's surface.
Richard Greenberg of the University of Arizona has considered three generic resurfacing processes: gradually laying fresh material on the surface; opening cracks which fill with fresh ice from below; and disrupting patches of surface in place and replacing them with fresh material.
The good news for the question of the origin of life is that there would be a delay of a couple of billion years before the first surface oxygen reached the ocean. Without that delay, the first pre-biotic chemistry and the first primitive organic structures would be disrupted by oxidation.
Credits: Image: Shaol Bartol.edu
shayol.bartol.udel.edu/~rhdt/diploma/lecture_8/hydrobot.jpg
Text: Space daily.com.
www.spacedaily.com/reports/Europa_Ocean_Contains_Enough_Oxygen_To_Support_Life_999.html