Aside from the fact that I am innately curious about such things, there was a bit of synchronicity involved. I am re-reading "Lucifer's Hammer", a novel by Larry Niven and Jerry Pournelle.
In that novel, the authors describe the discovery of a new comet and what happens when it (or, rather, large bits of it) impacts the Earth. Published in 1985, it described something that seems to have happened once before... about 12,900 years ago. It also describes what could happen if a similar event occurred today.
Imagine how the world might change if a large space object slammed into the Earth. All of our petty squabbles would disappear in a frenzied struggle for survival.
And the more we learn, the more possible such an event seems.