It was nearly the size of Mars, and that collision may have been what created our moon. An even bigger one hit billions of years ago. Ok, yes, I know that the catastrophic crash landing of the bolide, a seven-miles-across piece of galactic detritus, most likely an asteroid, that struck 66.043 million years ago, give or take, was not the biggest bad-parking-job in Earth’s history. Riley with Jet – image from The Museum of the Earth K-Pg (pronounced Kay Pee Gee – maybe think of it as KFC with much bigger bones, where everything is overcooked?) marks the boundary between before and after Earth’s own Big Bang, manifested today by a specific layer of stone in the geologic record.
This is a story about two things, Earth’s Big Bang and evolution. Virtually no environment was left untouched by the extinction, an event so severe that the oceans themselves almost reverted to a soup of single-celled organisms. The loss of the dinosaurs was just the tip of the ecological iceberg. This was the closest the world has ever come to having its Restart button pressed, a threat so intense that-if not for some fortunate happenstances-it might have returned Earth to a home for single-celled blobs and not much else. A chunk of space debris that likely measured more than seven miles across slammed into the planet and kicked off the worst-case scenario for the dinosaurs and all other life on Earth. Suddenly, inescapably, life was thrown into a horrible conflagration that reshaped the course of evolution. But no matter what we call it, the scars in the stone tell the same story.
That title was later revised according to the rules of geological arcana to the Cretaceous-Paleogene mass extinction, shorted to K-Pg. For years, it was called the Cretaceous-Tertiary, or K-T, mass extinction that marked the end of the Age of Reptiles and the beginning of the third, Tertiary age of life on Earth. Sometimes it’s called the end-Cretaceous mass extinction.
0 kommentar(er)
