The detection of hydrogen gas in the plumes of Enceladus is suggestive that like Earth, hydrogen is pouring into the Moon's subsurface ocean from hydrothermal activity on the seafloor.
Like Jupiter's moon Europa, Enceladus is believed to be surrounded by a global watery ocean covered by thick ice.
As for Jupiter's moon Europa, the observation is less definitive and more remote, coming from the Hubble Space Telescope. During its deepest and last dive through the plume on October 28, 2015, Cassini sampled the spray's composition using the ion and neutral mass spectrometer, or INMS. "We're pushing the frontiers, we're finding new environments, we're looking in a way we never thought possible before for environments in our solar system which may harbor life today".
Enceladus is a relatively tiny 500km-world has been recently explored by Cassini, a NASA spacecraft that has spent 12 years around the ringed exploring the moons around the ringed planet. The plumes include 1 percent hydrogen and the remainder is a combination of molecules such as ammonia, carbon di oxide, and methane. This new finding is therefore an independent line of evidence supporting the theory of hydrothermal activity taking place in the ocean of Enceladus. "Now we have detected molecular hydrogen, and through a process called serpentinization, where rock becomes nutrition, we get the stuff of life".
"Life as we know it requires three primary ingredients: liquid water; a source of energy for metabolism; and the right chemical ingredients, primarily carbon, hydrogen, nitrogen, oxygen, phosphorus and sulphur".
The U.S. space agency NASA has identified a moon orbiting Saturn as a new candidate for potential life.
Detecting hydrogen "really represents a capstone finding for the mission", Spilker said.
"We now know that Enceladus has nearly all of the ingredients you would need for life here on Earth", Spilker added. The team suggests that this phenomenon is a chemical effect of interactions between the rocky core and warm water from the underground ocean of the moon.
The surface of Enceladus.
Scientists say one of Saturn's outer rings was actually formed from hydrogen rich water and ice being released from Enceladus.
Waite said a process known as methanogenesis could provide the spark for life on Enceladus.
From these observations scientists have determined that almost 98 per cent of the gas in the plume is water, about one per cent is hydrogen and the rest is a mixture of other molecules including carbon dioxide, methane and ammonia. "They use this energy to synthesize some of their complex biomolecules".
In September, the spacecraft will plunge into Saturn's upper atmosphere, delivering its last images before it disintegrates on its final descent.
Two long running Nasa missions, the Hubble Space Telescope and the Cassini mission to Saturn, are providing the evidence necessary for further scientific investigations into extraterrestrial life. The Titan flyby will set up the first of 22 passes on April 26. The Europa Clipper mission is set to launch to Europa in the 2020s. Although Europa was long suspected to have a global subsurface ocean, scientists only confirmed it previous year after directly imaging what were suspected to be plumes erupting from the surface using the Hubble Space Telescope.
If the warm spot and the plumes are, in fact, related, "it could mean water being vented from beneath the moon's icy crust is warming the surrounding surface", the statement said.
The newly imaged plume rises about 62 miles above Europa's surface, while the one observed in 2014 was estimated to be about 30 miles high.