Cassini Spacecraft Detects Oxygen Around Saturn’s Moon: NASA
NASA’s Cassini spacecraft has detected molecular oxygen ions around Saturn’s moon Dione, according to a NASA press release Friday. Scientists posit that this discovery confirms the presence of a very thin atmosphere. In fact, scientists reveal that the oxygen ions around Saturn’s moon are extremely exiguous (one for every 11 cubic centimeters of space or approximately 2,550 per cubic foot). This fact highlights the thinness of Dione’s atmosphere.
For a comparison that might make more sense to the average reader, scientists believe that the atmosphere at Dione’s surface would only be as dense as Earth’s atmosphere 300 miles above the surface. The Cassini spacecraft’s detection of oxygen around Saturn’s moon is revealed in detail in a recent issue of the journal Geophysical Research Letters.
“We now know that Dione, in addition to Saturn’s rings and the moon Rhea, is a source of oxygen molecules,” said Robert Tokar, a Cassini team member based at Los Alamos National Laboratory and the lead author of the paper, in a NASA press release. “This shows that molecular oxygen is actually common in the Saturn system and reinforces that it can come from a process that doesn’t involve life,” Mr. Tokar added.
Scientists believe that Dione’s oxygen comes from either solar photons or energetic particles from space assaulting the moon’s water ice surface and freeing oxygen molecules. Despite this reasoning, scientists will continue to examine data from the Cassini spacecraft to see if the presence of oxygen around Saturn’s moon can be explained by geological processes or other events.
“Scientists weren’t even sure Dione would be big enough to hang on to an exosphere, but this new research shows that Dione is even more interesting than we previously thought,” said Amanda Hendrix, a Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory who was not directly involved in the study, in a NASA press release. “Scientists are now digging through Cassini data on Dione to look at this moon in more detail,” Ms. Hendrix added.