Reconstructing the Crime

Abstract

Just what happened to the dinosaurs? In the mind’s eye, travel back to the Cretaceous period, 65 million years ago. First, land in a region of the world that will someday be called Oklahoma. You are in the era of dinosaurs, although there are no longer as many species about, worldwide, as there were ten million or so years before. In all, 23 species roam their individual parts of the planet. It is their lack of spatial diversity that will make them vulnerable to the catastrophe that is about to befall the earth. So imagine you are there, together with triceratops, stegosaurus, velociraptors, and tyrannosaurus rex. Mostly they live off the land, and some of them live off each other. On this day none of the animals on earth can possibly have any awareness that they are about to disappear. Such a luxury will only be granted to a conscious species that has learned to explore the universe. For those who survive the initial impact explosion and its immediate consequences, the coming months will mark a terrible example of one of Cuvier’s “brief periods of terror.” In rapid succession, all life will be subject to a holocaust of staggering proportion, horrendous blast waves, searing winds, showers of molten matter from the sky, earthquakes, a terrible darkness that will cut out sunlight for a year, and freezing weather that will last a decade. The ozone layer will be destroyed, and acid rain will make life intolerable for species that survived the first few months after the impact. You are there and you have been observing an odd phenomenon in the sky. For thousands of years a great comet has loomed, repeatedly lighting up the heavens with its glorious tail and then fading away to reappear a few years later. Long ago it was seen to break into fragments, each of which was a spectacular sight in its own right. Sometimes one of those fragments seemed to loom ever so close to the earth. For thousands of years, spectacular meteor showers have been seen whenever the earth passed through the tail of one of those comets, and sometimes dust drifted down into the atmosphere and disturbed the climate.