That's exactly what Tommy Wallach's WE ALL LOOKED UP is. The story of Seattle teens whose lives are irrevocably changed when reports emerge of an asteroid on a fatal collision course with Earth, this novel deals not with the aftermath of the collision but with the build-up to it. (Spoiler which isn't really a spoiler: we never learn if the asteroid actually hits.)
What we do learn is how people, and especially young people, respond when their life expectancy is radically shortened by forces beyond their control. Some, predictably, give up. Others freak out. Some decide to fulfill unfulfilled dreams (singing on stage, dating a secret love). All, however, are changed by their realization of the ephemeral nature of life.
Wallach writes well, in a nicely controlled third person that jumps among his central quartet of characters: athlete Peter, who's begun to wonder whether prowess on the court is really all it's cracked up to be; photographer Eliza, whose father is dying and who fills the emptiness inside her with a series of meaningless sexual encounters; over-achiever Anita, who chafes against the life her parents have planned for her; and slacker Andy, who spends most of his time getting high with his dangerous and unpredictable friend Bobo. Watching the lives of these characters intertwine is what gives the book most of its considerable narrative drive. And it's nice to read a YA book that isn't afraid to philosophize and to touch on subjects of spirituality and ultimate purpose.
There are a few things about WE ALL LOOKED UP that are less successful. The book's second half is devoted in large part to an implausible rally-and-prison-break that seems to serve little purpose other than to generate artificial danger and thus hasten the development of romantic relationships. And the author's understanding of teenage girls is often badly off the mark, as for example in this head-scratch-worthy observation:
"Eliza was getting a distinct passive-aggressive vibe off Anita, and she had no idea why. It wasn't as if they were competing or something. Neither of them were interested in Andy, and Eliza was as bad at singing as Anita probably was at taking photos. Maybe it was inevitable--one of those rivalries that so often sprout up between girls, like mushrooms in the crevices of a forest, craning up toward whatever attention filters down through the canopy."
But Wallach is young, and one hopes he'll outgrow such sophomoric stuff. I recommend WE ALL LOOKED UP to those who want an original take on the end of the world.