On Earth, some organisms like it hot, some like it cold, and others feel at home only among the scalding acid jets of an undersea volcano.

That latter group — an ancient and eclectic bunch known as extremophiles — thrives in conditions that would kill your average Earthling. Members of the group tend to be microscopic in scale, and they include radiation-resistant tardigrades, pressure-loving prokaryotes at the bottom of the Mariana Trench and the acid-slurping bacteria that make Yellowstone’s Grand Prismatic Spring so colorful.