The Clockwork Rocket

 
 
The Clockwork Rocket
by Greg Egan

Night Shade Books

2011

 

 

Greg Egan has a reputation for writing some pretty high-concept hard science fiction. But even for Egan, Clockwork Rocket has a challenging premise. Egan imagines a universe where, among other differences, time is literally a fourth dimension of space and light of different colors travels at different speeds.

 
Yalda is a farmer's daughter who becomes something like her world's Einstein, discovering major properties of how space and time are related. Her discovery explains the mysterious rainbow streaks that've become common in the sky overhead during her lifetime, and predicts a coming danger - the streaks are bits of matter turned 90 degrees, so their 'time' is one of Yalda's world's spatial dimensions. This means that from the world's perspective, these 'Hurtlers' are moving infinitely fast, and might destroy the world unless someone can find a solution. Another planet in the same solar system is destroyed, making the threat seem all the more ominous.

 
With the help of a former student turned wealthy financier, Yalda develops a plan to turn a mountain into a generation ship. It will accelerate until it's moving at the speed of blue light (our light speed), traveling through space and toward tomorrow at the same rate, then keep accelerating until they've also turned 90 degrees to the world. No time at all will pass at home while they travel this way, meaning they can spend generations developing new science, then turn around, and come back. From the world's perspective, this journey will only take the four years needed to accelerate out, turn around, and decelerate on return.

 
Yalda and the other characters have recognizably human emotions and concerns, but biologically, they're totally different. Think of them as human-sized amoebas. They can make new limbs as needed and retract them at will, and the only way to reproduce is for a woman to divide her body into four. She ceases to exist and her children are raised by their father or a trusted friend. Yalda and the other women she hang out with all take a kind of birth control that prevents them from reproducing, letting them live to maturity and accomplish their goals.

 
Egan includes numerous lessons in the weird alternate physics of his universe, as Yalda and the others discover and explain how things work. The main plot is about the discovery of the danger, the race to build the ship, and then the challenges of bringing it up to full speed (including food crops that won't grow in zero gravity and the danger of space dust damaging the mountain). 

 
But the main obstacles aren't scientific or technological, they're political and cultural. Birth control is illegal in Yalda's home city, and women who want to delay reproduction are stigmatized and ostracized. The financier has a rich enemy who makes trouble for the project just to spite his rival. And there are the expected difficulties convincing the public of the danger from the Hurtlers and the need for their project. Rich as the financier is, the project needs workers to turn the mountain into a ship, and join the generations-long mission to save the planet. 

 
The reproductive rights of women are a major and recurring theme throughout the book, which ends when Yalda finally gives up her life to have children. Egan really humanizes his aliens, and shows great empathy for Yalda and the other women. There are two sequels, which I imagine will cover the trip out and the turn-around (2), and the trip back plus whatever they need to do to save the planet (3). This novel stands alone well enough, and the next two books are sure to get deeper into Egan's invented physics that I'm in no hurry to read them, if I ever do. But I am glad I read this one.