Astronomy
Extremophiles in Earth's Deep Biosphere and Implications for Extraterrestrial Life
Quick fact
Some microbes in Earth's deep biosphere can survive for millions of years without sunlight, using only chemical energy from rocks and water. They live kilometers below the surface, in conditions once thought to be sterile, and their existence has changed how scientists search for life on other planets.
Why this is interesting
You've probably heard that life needs sunlight, but what if I told you that most of Earth's living organisms—by sheer numbers—have never seen a single ray of it? Buried deep in rocks and sediment, they thrive in darkness, heat, and pressure that would kill a human instantly. How is that possible?