Jupiter's moon Europa produces so much oxygen a day that is enough for 1 million people

Jupiter's system serves as a kind of scaled-down version of the Solar System, attracting scientists and particularly astrobiologists. Beneath the ice covering the surface of Jupiter's large moons, global oceans with extraterrestrial biological life may be hidden. The NASA spacecraft Galileo previously detected the production of oxygen on Jupiter's moon Europa. A recent study from the Juno probe further strengthened the belief among scientists that Europa's ocean might contain oxygen.

Data from Galileo more than 20 years ago showed a significant variation in estimates of the amount of oxygen produced by Europa's icy shell. The moon's surface could release anywhere from a few kilograms to tons of oxygen per second. Oxygen on Europa is generated through the bombardment of its surface by charged particles from Jupiter, as this moon is located in the center of the gas giant's radiation belts. Radiation breaks down the water molecule (ice on the moon's surface) into hydrogen and oxygen. Probes' sensors capture ions of these elements and determine the intensity of their flows.

The Jovian Auroral Distributions Experiment (JADE) instrument on board the modern Juno probe collected data on charged particles near Europa during a flyby at an altitude of 354 km on September 29, 2022. As noted by the authors in a recent article in the journal Nature Astronomy, the analysis revealed the production of oxygen on Europa at a rate of 12 kg per second. This amount is sufficient to provide oxygen for one million people to breathe for a day. It's important to note that the instruments cannot directly detect the oxygen; the estimate is based on the registration of particles of atomic hydrogen.

"When NASA's Galileo mission flew over Europa, it opened our eyes to the complex and dynamic interaction between Europa and its environment. Juno provided a new opportunity to directly measure the composition of charged particles emitted from Europa's atmosphere, and we were eager to take another look behind the curtain of this captivating watery world," wrote the study's authors. "However, what we did not understand is how Juno's observations would place strict constraints on the amount of oxygen produced on Europa's icy surface."

The production of oxygen is one of many nuances that the NASA Europa Clipper mission will explore when it arrives in Jupiter's system in 2030 (the probe's launch is expected in October 2024). The probe will be equipped with sophisticated instrumentation comprising nine scientific instruments, allowing researchers to determine if conditions on Europa could support life. Even now, it is becoming clear that some oxygen reaches the subsurface ocean, where biological life may exist. However, Juno has not exhausted its scientific potential, and although its main scientific mission is complete, the spacecraft will continue to serve as a valuable source of knowledge for scientists.