Provides information on geologic time, including how far back the history of Earth can be traced, the reliable ways to estimate the age of geological formations on Earth, what the conditions were like in Earth's past, and more.

"In her third story, Luciana and her family are headed to Chile for winter break. Luci can't wait to see her cousins - but the reunion doesn't go as planned, and Luci feels like an outsider in her own family. Just then she receives a surprise invite from Claire Jacobs, her frenemy from astronaut training camp, to join her at the Mars habitat in the desert and watch NASA scientists at work. It's an offer too good to refuse, so Luci decides to leave...

"The Anthropocene is the current geological age, in which human activity has profoundly shaped the planet and its biodiversity. In this remarkable symphony of essays adapted and expanded from his groundbreaking podcast, John Green reviews different facets of the human-centered planet-from the QWERTY keyboard and Staphylococcus aureus to the Taco Bell breakfast menu-on a five-star scale. John Green's gift for storytelling shines throughout this artfully...