Seth is a surveyor, along with his friend Theo, a leech-like creature running through his skull who tells Seth what lies to his left and right. Theo, in turn, relies on Seth for mobility, and for ordinary vision looking forwards and backwards. Like everyone else in their world, they are symbionts, depending on each other to survive. In the universe containing Seth’s world, light cannot travel in … cannot travel in all directions: there is a “dark cone” to the north and south. Seth can only face to the east (or the west, if he tips his head backwards). If he starts to turn to the north or south, his body stretches out across the landscape, and to rotate as far as north-north-east is every bit as impossible as accelerating to the speed of light.
Every living thing in Seth’s world is in a state of perpetual migration as they follow the sun’s shifting orbit and the narrow habitable zone it creates. Cities are being constantly disassembled at one edge and rebuilt at the other, with surveyors mapping safe routes ahead.
But when Seth and Theo join an expedition to the edge of the habitable zone, they discover a terrifying threat: a fissure in the surface of the world, so deep and wide that no one can perceive its limits. As the habitable zone continues to move, the migration will soon be blocked by this unbridgeable void, and the expedition has only one option to save its city from annihilation: descend into the unknown.
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Very interesting. Mind bending.
Greg Egan probably writes some of the hardest hard SF I have ever read. Like Clockwork Rocket, this one is set in a universe where someone made a sign error in the formula to measure distances. In our universe, the “distance” between any two events is the sum of the physical directions minus the difference in time. In Clockwork Rocket he added time instead of subtracting it, and here, he subtracts a physical dimension instead of adding it.
The result is that light will not travel parallel to the pole of the world. Here that would look like a big black spot to the north or south when you are on the equator, and darkness looking up or down if you were in the arctic or on Antarctica. But that rule makes the world a different shape than ours too, and “weird” things happen if you turn towards or away from that “dark direction”. Surprisingly, you can move that direction, and sound travels that way too, you just can’t look there.
So the adventure is on, the characters run into a problem that forces them on a wild trip that ends up taking them from the equator to one of the poles, where all sorts of problems, while similar, have dramatically different consequences for the characters. And speaking of characters, like Clockwork Rocket, the author has a very different, alien form of life in mind for his story, but the two books are also dramatically different from each other too.
I found it to be an interesting book to read, but I did have problems trying to keep the directions straight, even though he did use north/south/east/west this time instead of made up names like in the other book. I think my problem was that one direction was just so dramatically different than the others, unlike the other book and our world where all the physical directions follow the same rules. It is definitely not for everyone, but should be good for anyone willing to put in some effort to explore a place where the physics is consistent, but incredibly different than ours even though the change in the math to make it that way is very small.
In a world where the dominant inhabitants are a symbiosis of two life forms and in which the laws of physics are very twisted, life can take place on both the vertical and the horizontal. There were times when I had to stop reading just to try and comprehend the landscape topography.
This is the first Greg Egan book that I have read, and it may be the most unusual Sci Fi book that I have ever read. It’s going to be fun exploring his other works!
This was a flat out wired book. I enjoyed it
rather strange, but entertaining, tale
The author takes you into a universe different from our own with only 2 spacial directions and 2 time directions. Greg Egan spins a tale in a mind blowing universe and you get to experience what changes in reality can do.
Hard sci-fi based on non-Euclidean space-time. Classic Egan.
Normally a terrific writer, he launches this time into such a twisted mathematical reality that every other page requires your deciding that, well, you’ll learn about thus LATER.” But you never do. A math physics puzzle, maybe, but not up to his par as a novel.
Once you get your head around the physics and geometry of this world, the storyline just sucks you in.