We know surprisingly very little about the moons which orbit the outer planets in our solar system. Only a few of our probes have made it out that far and their instruments were dated by today’s standards.
We do know that Saturn’s moon Titan has a thick atmosphere made mostly out of Nitrogen, like Earth’s. Unfortunately, Titan doesn’t have much in the way of Oxygen in its atmosphere. But what about the other moons, could any of them have a breathable atmosphere?
Saturn’s Moon Rhea
The Cassini space probe launched in 1997 has been studying the moons of the outer planets for over a decade. It has discovered that Saturn’s icy moon Rhea has a minimal oxygen and carbon dioxide atmosphere that is similar to Earth’s. Better yet, the carbon dioxide suggests that there might be life, and that humans could possibly breathe the air.
Oxygen it seems, is much more abundant than we ever suspected, specifically on moons that seem to be completely frozen solid. Recently, researchers found evidence of oxygen on Jupiter’s moons Europa and Ganymede, and now this finding on Rhea. In fact, because the region of space surrounding Saturn’s rings is oxygen rich, it’s thought even more of the icy moons within the gas giant’s magnetosphere likely have small atmospheres of their own.
A Little Help From Saturn
According to new data from the Cassini probe, the moon’s thin atmosphere is kept up by the constant chemical decomposition of ice water on the surface of Rhea. It’s likely that Saturn’s fierce magnetosphere continuously irradiates the ice water, causing chemical reactions which helps to maintain the atmosphere.
Researchers suspect a lot of Rhea’s oxygen isn’t actually free right now, but is instead trapped inside Rhea’s frozen oceans. While you could never walk around on the surface of Rhea without a space suit, it would be an ideal candidate as a ‘gas station’ for astronauts to replenish water and oxygen for any extended long mission trips.
While the presence oxygen is relatively easy to understand, the carbon dioxide is even more intriguing. The gas is likely created by reactions between organic molecules and oxidants down on the moon’s surface. That seems rather shockingly Earth-like, or at least like the Earth of a few billion years ago.
This is just further proof that the building blocks and basic prerequisites of life exist all throughout the solar system, even if it was apparently only on Earth where conditions were ‘just right’ for it to actually lead to something fantastic.