In 2005, images of a brilliant watery plume erupting from the surface of Saturn’s moon Enceladus captivated the world. The giant column of vapor, ice particles, and organic molecules spraying from the moon's south polar region suggested that there’s a liquid water ocean below Enceladus’ ice shell and confirmed the moon is geologically active. The plume also thrust Enceladus and other worlds in the outer solar system, with no atmospheres and far from the heat of the Sun, toward the top of NASA’s list of places to search for signs of life.
Scientists now are preparing for a mission to another ice-covered ocean world with possible plumes: Jupiter’s moon Europa. Scheduled to launch in 2024, NASA’s Europa Clipper spacecraft will study the moon from its deep interior to its surface to determine whether it has ingredients that make it a viable home for life.
Like Enceladus, Europa is geologically dynamic, meaning both moons generate heat inside as their solid layers stretch and flex from the gravitational tug-of-war with their host planets and neighboring moons. This, instead of heat from the Sun, keeps subsurface water from freezing on these ice-covered moons. The heat may also help produce or circulate life’s chemical building blocks at the seafloors, including carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
But that’s where the similarities end.
To read more, click here.