What would be the implications if the Moon were destroyed? Well, first the fragments would create more fragments, which would eventually start falling to Earth, boiling the oceans and destroying all life on the surface. So it’s time to get underground or get into space.
Stephenson was clearly more interested in the near term effects, mostly in terms of physics and politics. The “escape from Earth” part of the book is dense and detailed, and takes up two thirds of the book. Then, it fast forwards five thousand years and races to a conclusion through what feels like a grab bag of Stephenson’s ideas for other novels.
Still, this was a thought-provoking, great read. If the last third was less satisfying, the first two-thirds made up for it.