for the martians


Oxygen atmosphere found

around Saturn’s moon Rhea.

The 2 March 2010 Rhea flyby trajectory and simulated oxygen atmosphere distribution. Inset: Predicted oxygen density (yellow) compared to the INMS measurement (white) during the flyby. Image © Science/AAAS

 

Universe Today:

In March of this year, the Cassini spacecraft made a close flyby of Rhea and recorded data showing a thin atmosphere made up of oxygen and carbon dioxide.

The source of the oxygen is not really a surprise: Rhea’s density of 1.233 times that of liquid water suggests that Rhea is three quarters ice and one quarter rock. The moon’s tenuous atmosphere is maintained by the ongoing chemical decomposition of ice water on the moon’s surface by irradiation from Saturn’s magnetosphere.

Oxygen has also recently been detected in the atmospheres of two of Jupiter’s moons, Europaand Ganymede. Since oxygen is a main component of the atmosphere surrounding Saturn’s rings, astronomers think there could be similar atmospheres around other icy moons that orbit inside Saturn’s magnetosphere.

The scientists said the oxygen appears to rise to an atmosphere when Saturn’s magnetic field rotates over Rhea. Energetic particles trapped in the planet‘s magnetic field pepper the moon’s water-ice surface. They cause chemical reactions that decompose the surface and release oxygen.

Releasing oxygen through surface irradiation could help generate conditions favorable for life at an icy body other than Rhea that has liquid water under the surface, Teolis said. If the oxygen and carbon dioxide from the surface could somehow get transported down to a sub-surface ocean, that would provide a much more hospitable environment for more complex compounds and life to form.

Universe Today

More oxygen in the universe? Say it isn’t so. Only time will tell if the moon could be eligible for living conditions by humans in the future, when Earth’s resources run low or Earth orbits to close to the sun