But what if it were ending two years from now? Would people keep going to work? Would kids go to school? If they did, what would you teach them? If everyone learned that the world would end two days from now, there would be global panic, plus a big dose of hedonism. The other thing that struck me is the way the book pushes you to think big and long-term. But if you’re the sort of reader who doesn’t care how such a thing might work, you will find yourself skimming parts of Seveneves. There’s a long but clever passage about a woman who flies from Earth into orbit in a glider while wearing a suit made of intelligent fabric. You’ll learn the difference between fuel and propellant. You’ll learn all about how orbits work and what it takes to connect two spacecraft in different orbits. Stephenson tells you not just what happens, but how it happens. Everything adheres to physical laws, so unlike Star Wars, no one travels anywhere near the speed of light. Seveneves belongs in the subgenre of hard science fiction, which means it emphasizes scientific accuracy. One is Stephenson’s writing on technology. So I will just touch on two things that really struck me. The book has so many cool ideas, memorable characters, and good storylines that I can’t cover them all. The world unites on a plan to get as many spacecraft as possible into orbit, where a few select people can ride out this Hard Rain and keep humanity going. “The moon blew up without warning and for no apparent reason.” People figure out that in two years, chunks of the moon will rain down on Earth in a cataclysmic meteor shower, wiping out every living thing and leaving the planet uninhabitable for thousands of years.

This isn’t a spoiler-it’s the first sentence of the book. The plot of Seveneves gets going when the moon blows up without warning and for no apparent reason.

Seven eves