Active Surface and Interior of Europa as a Potential Deep Habitat

Jupiter’s moon Europa may have an internal ocean of liquid water, along with the chemical compounds and energy source that life requires. Europa is covered by the solid icy shell, similar to other solid bodies in the outer solar system. The solid icy shell fractures and deforms creating cracks, ridges, and bands in relatively a recent period. Galileo spacecraft data indicates a warm interior, which means a convecting icy shell above a liquid water ocean. In addition, Hubble Space Telescope recently found a signature of active water plumes from the southern hemisphere. Here the current knowledge on the characteristic of Europa, geology, composition, interior, and surrounding environment, in the relation to the possible presence of life will be summarized. Future spacecraft exploration plans for Europa and their science objectives are also introduced. With the understanding of Europa’s potential for life, we can consider another style of habitable world hidden by the icy surface, “deep habitat,” which is different from Earth’s one, and can address the fundamental question: Are we alone in the universe?