An oxygen atmosphere has been found on Saturn’s second largest moon, Rhea, astronomers announced Thursday.
For one thing, the 932-mile-wide (1,500-kilometer-wide), ice-covered moon is more than 932 million miles (1.5 billion kilometers) from Earth. For another, the average surface temperature is -292 degrees Fahrenheit (-180 degrees Celsius).
And at less than 62 miles (100 kilometers) thick, the newfound oxygen layer is so thin that, at Earthlike temperatures and pressure, Rhea’s entire atmosphere would fit in a single midsize building.
Still, the discovery implies that worlds with oxygen-filled air may not be so unusual in the cosmos.
Source: National Geographic
