'Maybe they're waiting for something that only happens thousands of years later': The hidden life 'sleeping' deep beneath Earth for millions of years

A fracture in the earth's crust in the rift valley between the American and Eurasian continental plates in Iceland. .

Beneath Earth's surface lies a kingdom of undiscovered microscopic life. These "intraterrestrials" survive in some of the harshest conditions on the planet — and scientists are hunting for these microbes.

In this excerpt from "Intraterrestrials: Discovering the Strangest Life on Earth" (Princeton University Press, 2025), author Karen G. Lloyd, a microbial biogeochemist at the University of Southern California Dornsife, examines the idea of evolution among life that can survive for hundreds of thousands — if not millions — of years in a dormant state and what it might be waiting for to "wake up."