If life beyond Earth is anything like life as we know it, it’ll find a way to populate even the most improbable landscapes. Here, volcanic lakes, acid pools, desiccated basins, and subterranean caverns are no match for biology. On Mars, or the icy moon Europa? Someday, we’ll know the answer.
To really learn about how life emerges, evolves, and flourishes‚ and to improve our chances of detecting it elsewhere in the solar system—scientists look for life in Earth’s harshest environments. That means going to the extremes—to the hottest, darkest, driest, most acidic, saltiest places on the planet—and seeing what’s there.
These environments in this gallery are among the closest we can get to alien worlds without actually going there. When scientists need to test rovers destined for Mars or beyond, they trek out to the Arctic or the California desert. As engineers work through the challenges of exploring alien oceans, they take their submersibles for a frigid polar swim. In a very real way, looking for life beyond Earth sometimes means turning Earth into an alien analog.