Illustration from NASA: An artist's rendering of how scientists theorise water interacts with rock in the ocean on Saturn's ice moon, Enceladus.
The discovery was made using NASA's Cassini spacecraft which is nearing the end of a 13-year mission exploring Saturn and its 62 orbiting moons. The existence of water in Europa increases the expectations of finding alien life in a nearby environment, joining Enceladus, one of Saturn's moons which may also harbor life.
The hydrogen was detected during a 2015 flyby when NASA's Cassini spacecraft raced through plumes of vapor spewing from cracks at the moon's south pole, scientists said.
The National Aeronautics and Space Administration (NASA) has announced they have new evidence for the most likely places to find life beyond Earth and those places are closer than you may think. Either way the implications are profound.
"This is the closest we've come, so far, to identifying a place with some of the ingredients needed for a habitable environment", said NASA administrator Thomas Zurbuchen.
"With this finding, Cassini has shown that Enceladus - a small, icy moon a billion miles farther from the sun than Earth - has almost all of these ingredients for habitability", NASA said in a statement announcing the findings. Another paper published recently focuses on Jupiter's moon, Europa, and its subsurface ocean. Searching for hydrogen was a key goal of Cassini's final and closest dive through the plumes. Research bears out that hot water is reacting chemically with rock on the moon's seafloor, producing molecular hydrogen.
Scientists agree that life requires liquid water, a source of energy for metabolic activities, and a coherent combination of chemicals, these primarily being carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur.
This June 28, 2009 image provided by NASA, taken by the global Cassini spacecraft, shows Enceladus, one of Saturn's moons. Details of the discovery were published in the journal Science today.
The Juno spacecraft is in orbit around Jupiter, but the mission has been designed in such a way that Juno does not go anywhere near Europa, to avoid contaminating the icy moon in case it had life.
Cassini mission researchers looked into the results from images taken, which found plumes. A possible plume of material has also been spotted erupting from the surface of Europa a year ago, in the same place that one was spotted by Hubble in 2014.
Through the study what surfaced up is that the moon has hydrogen for ecosystems. This is because the rocky core of the icy Saturn moon is believed to have similar chemical properties to meteorites, which contain both sulfur and phosphorus. The team concluded that as long as the seawater has a certain level of acidity, it is replete with hydrogen and carbon dioxide, providing a lot of food for microbes, Waite says.
There are believed to be oceans on three of the moons of Jupiter, including Ganymede, Callisto and Europa. Scientists discovered via these samples that the plume consisted of 98% water, roughly 1% of hydrogen, and a mixture of other molecules like carbon dioxide, methane, and ammonia.
The chemical elements found on Enceladus, when combined on earth, suggest life is around.
The Europa Clipper will be equipped with a powerful ultraviolet imaging system that will be able to make close-up, high-resolution observations that should reveal the nature of the presumed plumes and whether they represent water escaping through the surface cracks. Observations from the Galileo spacecraft was used to corroborate the Hubble findings, to show that the region was unusually warm. Here's more info on that mission and Europa as a whole.