By analyzing data collected by the Cassini spacecraft in April 2010, during its flight over one of the 62 satellites of Saturn, U.S. scientists at Los Alamos National Laboratory have discovered oxygen molecules in the exosphere of Saturn’s moon Dione (pictured) – which coincidentally was discovered by Giovanni Domenico Cassini in 1684.
The presence of a thin atmosphere surrounding Dione confirms a hypothesis made after the discovery by the Hubble Space Telescope of an ozone layer in the periphery of the moon. There were some doubts about that theory, in regards to its ability to retain an atmosphere because of its low density.
However, this does not mean that there is breathable air on Dione. According to calculations by the team of Robert Tokar and Michelle Thomsen, who published their results in the scientific journal Geophysical Research Letters. Dione’s air has an oxygen concentration roughly the same as the atmosphere 480 kilometers above the Earth’s surface.
It is believed the oxygen molecules present on Dione and not related to the presence of organic life, but instead likely resulted from from the bombardment of ions produced by Saturn’s magnetic field or by solar photons from the sun. Researchers believe that one or both of these influences striking the ice that covers Dione, liberates oxygen ions.
This discovery is particularly significant because the same phenomenon may also occur on other moons surrounding Saturn – including Enceladus, where scientists hope to find an ocean under its thick layer of ice where a form of life comparable to that found in Antarctica may have developed.
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