Water vapor on Jupiter's moon Europa confirmed once and for all
With growing suspicions of a huge salty ocean hiding beneath its frosty shell, Jupiter’s moon Europa is increasingly seen as one of the more likely bodies to harbor life in our solar system. Surface plumes that appear to eject water into space have played a huge role in shaping this perception of late, and scientists at NASA have now directly confirmed water vapor within them for the very first time.
Data collected from different space missions over last few decades has seen the scientific community grow more and more emboldened by the possibility of life on Europa. This included the Galileo probe’s measurements of an irregular magnetic field in the late 90s and early 2000s, which were seen as indicative of a sloshy, conductive liquid beneath the surface.
Then in 2012, the Hubble Space Telescope revealed evidence of water vapor over Europa’s south pole, which scientists believed to be the result of plumes carrying material from beneath its surface out into space.
Another 2016 study strengthened this hypothesis, by using the transiting techniques we rely on to hunt exoplanets to show plumes erupting from the surface. A re-examination of Galileo data last year, meanwhile, found strong evidence that probe passed right over the top of them in 1997.
All of this points to the strong possibility that Europa harbors some water, somewhere, and now NASA has removed all doubt. This first definitive evidence comes via the W. M. Keck Observatory in Hawaii, where an international team of researchers tapped spectrograph data to analyze the chemical composition of Europa’s atmosphere.
More specifically, the team was searching for certain frequencies of infrared light that pertain to certain types of molecules. In doing so, for the first time ever, it uncovered the direct evidence of water vapor above Europa.
“Essential chemical elements (carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur) and sources of energy, two of three requirements for life, are found all over the solar system. But the third — liquid water — is somewhat hard to find beyond Earth,” said Lucas Paganini, a NASA planetary scientist who led the water detection investigation. “While scientists have not yet detected liquid water directly, we’ve found the next best thing: water in vapor form.”
Paganini’s team found these spurts of water erupting from the surface to be infrequent, occurring only once during 17 nights of observations. But when it did erupt, it did so with full force, releasing 2,360 kilograms per second – enough water to fill an Olympic-size swimming pool in minutes.
While scientists now strongly believe there to be a subsurface ocean on Europa, another possible source of the water vapor could be shallow pools of melted water not all that far beneath the surface.
NASA’s recently confirmed Clipper mission to Europa will help to fill in some of these blanks. The unmanned probe is being developed for an intense study of the moon, to survey its surface, atmosphere, interior, and likely subsurface ocean. The spacecraft is expected to launch around 2025.
The video below provides an overview of the latest Europa discovery.