Life, as is known, requires three main ingredients to originate, exist, evolve or function - liquid water, energy source for metabolism and the right chemical ingredients including oxygen, hydrogen, carbon, nitrogen, phosphorus and sulfur.
Cassini has found that nearly all of these ingredients are there on Enceladus, a tiny icy moon at a distance of a billion miles away from Saturn.
Jupiter's moon Europa is another so-called "ocean world" in Earth's outer solar system that is believed to harbor a sea of tidally heated water beneath its frozen crust.
WASHINGTON-NASA has announced that there may be proof of life outside of earth.
The agency announced Thursday that they've found evidence of hydrogen gas pumping into an ocean beneath the surface of Enceladus, a moon orbiting Saturn.
From these observations scientists were able to find that almost 98 percent of the gas in the plume is water, about 1 percent is hydrogen and the remaining is a mixture of other molecules including carbon dioxide, methane and ammonia.
Due to the finding, NASA directed Casini to plunge through this vapor which collected thousands of particles using instruments such as the Ion and Neutral Mass Spectrometer (INMS).
Cassini only had instruments created to investigate the outer atmosphere of another of Saturn's moons, Titan. But similar plumes have erupted less frequently on Jupiter's moon Europa, which has a similar icy shell to Enceladus, presenting potentially correlating life-fostering conditions.
Waite, who works with the Southwest Research Institute in San Antonio, Texas, said in an interview: "The next time we go back. not only picks up on the habitability story, but it starts looking for evidence for life".
"That's just going to be a tremendous opportunity to test our theories and see if there's life there", said James L. Green, director of planetary science at NASA.
The new findings, published in the USA journal Science, are an independent line of evidence that hydrothermal activity is taking place in the ocean of Enceladus, a small, icy moon a billion miles farther from the sun than Earth. The final step is the molecular hydrogen being produced, which has the chemical energy to support microbial systems in the ocean. That's what the plumes are about on Europa as well.
The hotspot will be a target area for the powerful ultraviolet camera onboard the Europa Clipper spacecraft.
Researchers using Hubble also found large plumes of gas and ice erupting on Europa, which is about the size of Earth's moon and the smallest of Jupiter's four satellites. The plume's reach was apparently 62 miles (100 kilometers) above Europa's surface. Observations from the Galileo spacecraft was used to corroborate the Hubble findings, to show that the region was unusually warm.
"Based on the data, NASA believes that it's possible for simple life such as bacteria to live on the seafloor of Enceladus, adding that they will be excited with any discovery of life". The next mission to Jupiter's moon may find a habitable environment. Sparks led the Hubble plume studies in both 2014 and 2016.
The plumes of water from icy moons with global subsurface oceans such as Enceladus and Europa, allow scientists to study the subsurface oceans without having to drill through the ice sheets covering most of the planets, and sending robotic probes into the oceans.