Picked this up from the library on impulse after an article at Boing Boing made me curious about Greg Egan’s work. Not on my reading list, but I succumbed to convincing myself that I deserved an indulgent hard sci-fi treat after successfully reading a much broader range of books than my past habits have dictated.

The Newport library had several Egan novels in the stacks, and I chose which one to take home by browsing jacket flaps, and I can’t tell you the last time I did that ever. The jacket copy on Schild’s Ladder rang a bell; I recalled mention of this novel on the Wikipedia entry about false vacuum, a deliciously creepy deep-science disaster scenario. To quote that article:

A bubble of lower-energy vacuum could come to exist by chance or otherwise in our universe, and catalyze the conversion of our universe to a lower energy state in a volume expanding at nearly the speed of light, destroying all that we know without forewarning.

Yes, I could not say no to a novel from a recommended author using that as its setup.

The bubble in Schild’s Ladder, made of “novo-vacuum”, doesn’t quite follow these rules, expanding at the leisurely pace of 0.5 c. Touched off by a well-meaning scientific experiment some 20,000 years in the future, it begins to eat up a Milky Way populated by post-humans so advanced that staying ahead of the bubble’s encroaching border presents a mere inconvenience, at worst. However, nobody likes watching their homeworlds inexorably consumed, one after another, with old Earth itself on the eventual menu. So, the bulk of the story takes place centuries after the initial accident aboard a scientific vessel located right on the expanding border, matching velocities with it, tasked with studying the horrible thing and figuring out how to best cope with it.

So, that’s a setting! I enjoyed taking all that in, and I also loved the concept of what lay on the other side of the border: a separate universe whose laws essentially set up an unfathomably large cellular automaton, with pixels (or voxels, really) on the scale of Planck lengths. It’s packed end-to-end with active stuff, and most of the stuff past a certain scale of size and complexity seems inarguably alive. The story’s human characters realize with awe that our own universe — containing vast amounts of nothing at all, dusted with homeopathic quantities of matter — looks like a terribly degenerate specimen in comparison with this teeming new world.

Against this backdrop, two factions among the human scientific community squabble: one wants to destroy the bubble and guarantee our old universe’s safety, while the other wants to preserve and study the new universe. Did I find myself feeling extra sympathy for this arrangement after my brush with the game Ingress? Yes, perhaps I did.

Schild’s Latter also has some interesting speculation about the fate of sexuality and gender (and biological dimorphism at all) within a long-lived human species. As for the book’s many pages devoted to either the narration or character dialogue expounding upon applied many-worlds theories and quantum physics both real and imaginary, I must confess I largely skimmed over them. Egan’s charmingly archaic (but regularly updated) website contains pages explaining how decoherence works in quantum mechanics, insisting that it plays a role throughout the events of this book, and… I’m ready to believe him, I suppose, but I didn’t find comprehension of it necessary to enjoy the story.