If one cannot rely on established teachings to provide a guiding light, then neither can we blindly adhere to the old cliché that things will simply fall into place. Denise, Eli and Adam approach middle age, startled to find that their future lives have been fixed by the cowardice and inaction of their younger years. How can we start again, Eli muses, when we have consumed all our second chances? "You chance everything, ruin  everything once again, wreck it all and still you aren't left with a fortune." Greer's protagonists pursue astronomy because, while magical and exhilarating, the universe can be defined within quantifiable terms, and its problems solved by logic and reasoning. Love remains the scientists' great mystery, no more forthcoming than an unseen comet still light years away.