I've thought a lot about how Seveneves could be adapted, and man ... it's going to be a tough thing to pull off. A movie trilogy might be able to cover half of it. Were I to do it myself, I'd probably go for a three-season TV series, with each season being one of the parts of the novel. I have no doubt that there's a ton that can be cut from an adaptation, but I'd be hard pressed to cut much, personally. I'm very bearish on any potential adaptation to a single film, as much as I'd love to see one happen.