Because the caves, mines, and crevasses on Earth are filled with extremophiles, NASA uses those lifeforms as a guide to its exploration of the universe. The hidden parts of the planet have to make their own way of survival. Surface life has photosynthesis, but subsurface only a tiny fraction of that energy trickles down so they process minerals from rocks. These lifeforms could be a model for another way life on Mars or Europa or somewhere else! An important aspect to consider if there is life elsewhere would be how to study the environment without contaminating it. Penny Boston, the new director of NASA’s Astrobiology Institute, is on a mission to search for evidence of other life and inspire others to do the same.