Egan takes the typical sci-fi space epic in a new direction with a universe in which normal laws of physics as we understand them simply don’t apply. Light doesn’t travel at a constant speed, instead, its velocity is dependant on its wavelength and it generates energy. In a fair approximation of spontantious generation, plants make and subsequently feed on their own light. On a small world in this alternative universe Yalda, the daughter of simple stock has the unusual opportunity of attending school, eventually rising above her humble roots to become a renowned scholar. When a barrage of meteors known as the Hurtlers threatens Yalda’s world, an ambitious and audacious plan is set into motion. A spacecraft traveling at incredible speed will embark upon a mission to find a way to save their world from annihilation. For the spacecraft’s inhabitants the journey will take lifetimes but because of the laws of physics, only a few years will have passed by the time the descendants of the original crew return. The question is, will it work?This imaginative, physics heavy read takes more effort to get into then some lighter sci-fi’s on the market but the story and characters are worth it. The alternate physics are elegantly described and make surprising sense as the laws all remain true to that particular universe. The premise of a world facing destruction by meteor bombardment is not so farfetched as to stretch credibility and Yalda’s view allows readers an intimate window into her world. Egan has done an excellent job of expanding on an interesting thought experiment and turning it into a nicely told tale.