New research suggests that there’s less oxygen on the icy surface of Jupiter’s moon Europa than previously thought — and that could affect what, if any, life lurks in Europa’s subsurface ocean.
Even with little or no oxygen, microbes can still roam the oceans thought to exist miles beneath Europa’s frozen crust. As for what else, “who knows”, the Nasa scientist Kevin Hand, who was not involved in the study published Monday in Nature Astronomy.
More work is needed to confirm these findings, which contradict earlier telescope observations of condensed oxygen in Europa’s ice, which indicate a higher oxygen concentration, Hand said.
The new study is based on data collected by Nasa’s Juno spacecraft during a particularly close flyby of Europa in 2022 – a distance of just 219 miles (353 km).
An American-European team calculated that between 13 and 39 pounds (6 and 18 kg) of oxygen is produced on Europa’s surface every second.
Previous estimates had a much wider spread, with as much as 2,245 pounds (1,100 kilograms) of oxygen being produced per second. So “unless Europa’s oxygen production was significantly higher in the past”, the new measurements provide “a narrower range to support habitability”, the researchers wrote.
This oxygen is formed along with hydrogen as Jupiter’s radiation explodes Europa’s global shell of frozen water.
Lead author James Szalay of Princeton University said Juno’s flyby was the first time a spacecraft had “directly sniffed” Europa’s environment. “We couldn’t wait to peek behind the curtain of its complex environment,” he said in an email.
Although it was “a significantly narrower range than we previously thought, there is still a lot we can learn”, Szalay said.
It is unknown how much oxygen escapes into the moon’s atmosphere, how much remains in the ice and how much may find its way into the subsurface ocean.
Nasa plans to launch the Europa Clipper this fall. The spacecraft will make dozens of close flybys of Europa – almost the size of our moon – as it orbits the giant gas planet.
