Finding life there would be a profound revelation that we are not alone in the cosmos. Furthermore, the discovery of organisms—or the lack thereof—could answer the subtler mystery of how life started on Earth. Researchers at the meeting presented two major opposing theories about how life here originated (in the ocean versus on land), and the group discussed how exploring Enceladus would inform this debate. “It would be a test of one of the ideas about the origin of life,” Porco says—specifically, the proposition that Earth’s species sprang in the sea. For example, if organisms exist in Enceladus’s ocean and presumably arose there, it would support the theory that life began on Earth in hydrothermal vents (hot, nutrient-rich, deep-sea vents on the ocean floor) rather than in patches of water on land.
Enceladus could also teach us about genesis in our solar system in other critical ways. “You’re not just searching for life, you’re searching for an understanding of the nature of that life, and how it compares to life on Earth,” says Chris McKay, a planetary scientist at NASA Ames Research Center. For instance, if we discover that creatures on Enceladus are nothing like those on Earth—if their biochemistry is completely different—then it would likely mean that the two forms of life arose separately and independently, and thus, that aliens might be likely to exist other places as well. “If life started at least twice in our solar system, then you know the universe is full of life,” McKay says. Or, if we find out that Enceladus organisms and Earth organisms are made in identical ways, it may indicate that life originated someplace else, and was carried to both worlds. If Enceladus is barren, however, it could support the theory that life needs an environment on dry land to get started, not an ocean. Regardless of what a mission to Enceladus might discover, the answer will tell us something fascinating.
revelation n. 启示；揭露
organism n. 有机体
planetary adj. 行星的
barren adj. 贫瘠的