Incipient Civilizations Rising. Then Something Stops Them. This Pattern Repeats Through the Holocene

Twenty five years ago the Younger Dryas impact hypothesis did not exist. The Holocene impacts that researchers now consider almost certain to have occurred were unknown. The Bronze Age collapse - a global civilizational catastrophe that wiped out multiple sophisticated cultures simultaneously - had not yet been seriously examined through the lens of cosmic impact. Randall’s point is direct - what has been learned in the last quarter century ups the ante on the cosmic impact threat considerably beyond what was understood when the foundational research on planet crossing orbits and impact rates was first conducted.

The pattern Randall traces through the Holocene is the one that makes the full picture so significant. Multiple times within the current geological epoch, incipient civilizations have been on the rise - developing sophistication, complexity, and the kind of organizational capacity that could have led to something enduring. And each time, something has aborted that ascendancy. The Bronze Age collapse is the most dramatic documented example - global in scale, almost certainly caused by impact or multiple impacts, followed by a cascade of secondary consequences that reset the civilizational clock across multiple regions simultaneously. The higher the number of objects in planet crossing orbits, the higher the probability that one of those resets is coming. And the last 25 years of research suggest there are considerably more such objects than anyone understood when the baseline calculations were first made.