This cutaway view of Saturn's moon Enceladus is an artist's rendering that depicts possible hydrothermal activity that may be taking place on and under the seafloor of the moon's subsurface ocean, based on recently published results from NASA's Cassini mission. Hydrothermal activity is a process where seawater infiltrates and reacts with a rocky crust, emerging as a heated, mineral-laden solution. Researchers think microscopic grains of rock detected in the Saturn system most likely form when hot water containing dissolved minerals from the moon's rocky interior travels upward, coming into contact with cooler water. Gravity science measurements from Cassini also suggest Enceladus' rocky core is quite porous, which would allow water from the ocean to percolate into the interior. This would provide a huge surface area where rock and water could interact.