
"What would happen if the world were ending? A catastrophic event renders the earth a ticking time bomb. In a feverish race against the inevitable, nations around the globe band together to devise an ambitious plan to ensure the survival of humanity far beyond our atmosphere, in outer space. But the complexities and unpredictability of human nature coupled with unforeseen challenges and dangers threaten the intrepid pioneers, until only a handful of survivors remain... Five thousand years later, their progeny--seven distinct races now three billion strong--embark on yet another audacious journey into the unknown... to an alien world utterly transformed by cataclysm and time: Earth"
> as a complete and utter Stephenson fanatic, even I abandonded him at Anathem.
You might want to give his later stuff a try. I think he's really improved his ability to wrap a story up, without compromising on the grand ideas.
I also liked Seveneves, but it should have ended 2/3 of the way through. There was a point that would have made for an excellent ending (which is something Stephenson famously struggles with IMO), but then he forced in another 1/3 of a book that didn't engage me and which felt like it just petered out.
https://what-if.xkcd.com/46/ - while it deals more with the Earth (which has a more molten core), its still applicable. There's still molten material ( https://science.nasa.gov/moon/composition/ ) but it's a lot deeper.
> (or blows the Moon up)
As a classic Neal Stephenson (great world building, good plot... and it ends)... Seveneves starts with:
> THE MOON BLEW UP WITHOUT WARNING AND FOR NO APPARENT reason. It was waxing, only one day short of full. The time was 05:03:12 UTC. Later it would be designated A+0.0.0, or simply Zero.
... and given the book and the "what happens"... a watch surviving (much less keeping the phase of the moon) would be impressive.
There's also the Dr. Who take ("Spoilers") https://youtu.be/pHOnGSFzd3Y