Graham Hancock my behind.
The Cycle of Cosmic Catastrophes:
Flood, Fire, and Famine
in the History of Civilization
by Richard Firestone,
Allen West, and
Simon Warwick-Smith
I kow that the YDHT did not originate with Hancock, but with FIrestone, et al. I have known about the YDHT since its inception (2007) but the bit about the bollides falling for some 21 years was new to me. I will have to go back and find the original source on the bollides falling for that amount of time.