Super Short Summary

Seveneves by Neal Stephenson is a hard science fiction novel in which an unexplained event shatters the Moon, making Earth uninhabitable and forcing humankind to seek survival in space. People enter a "Cloud Ark" aiming to preserve humanity until Earth stabilizes in 5,000 years, leading to a society divided into seven new races. The story spans from the catastrophic event to the eventual effort to terraform Earth. The novel includes themes such as global catastrophe and human survival.