The Eternal Flame: Orthogonal Book Two Paperback – August 13, 2013

I had high expectations for this book, and it totally lived up to them! The characters are all new, the problems facing them are interesting, and the science - oh god - the science is so hard, and so AWESOME! Not to spoil too much, but the inhabitants of the Peerless make great breakthroughs in both physics and biology. There is some political and social strife, sexism, etc., but it doesn't spoil this fun read. After all, big scientific progress often provokes social resistance. Some of the action is really awesome, like the voyage to the orthogonal space object, and there's even a scene where someone is rescued from being lost, floating in space! I can't wait to read the third book...

Solid continuation of the story line. Great exploration of the ramifications of the main characters' reproductive biology, though the development of the alternative went way too smoothly from a scientific/engineering point of view.

Simply the best hard core science fiction on the market today. Greg Egan realizes this alternate universe through the single change of a 'minus' to a 'plus' sign, and then, like the big bang, the rest of the universe follows from there. An awesome work on intellect and imagination. And lots of Easter eggs for the reader to figure out too.

The Clockwork Rocket and The Eternal Flame (Greg Egan) are the first two books of the Orthogonal trilogy. I haven't gotten to the third yet, and I might not, but I want to write this review while the first two are fresh in my head.So, science fiction. You might expect, from the name, that fictional science were a common thing. Actually it's not *that* rare, but Orthogonal really takes it to an extreme.The basic fictional science is an alternate version of quantum mechanics and relativity. The world's geometry is Riemannian, not Lorenzian. What that means is approximately that time is a dimension not fundamentally different from space there, while time and space are quite different here. In particular, you can make a rocket ship there, and make a certain right-angle turn, and turn one of your space dimensions into time and time into a space dimension. So time on your spaceship can pass (normally, for people on it), but no time on the world you started from will pass.Egan does work out a lot of important physics. Like: stars are rainbow streaks in the sky, smeared out in the direction of their motion. Like: emitting light *increases* energy, which means that plants radiate light and eat the energy it produces. Like: every piece of matter really wants to gain more and more and more energy until it explodes.In the Clockwork Rocket, this theory gets worked out at about the same time that a cosmological disaster starts to strike. The technology of the day is not sufficient to deal with the disaster. So they build a spaceship-cum-timeship and send it off orthogonally, to have generations pass, and in time, hopefully, invent a way to deal with the disaster.So that clockwork rocket in the title? It's a whole huge *mountain*. Whatever else I say about this book, I must praise the author's imagination. That's all cool, and first-class hard science fiction.But: a large fraction of the book is characters talking to each other figuring out the equivalent of quantum theory for their world.Now, I like quantum theory. I chew on quantum theory textbooks in my spare time, sometimes. I even occasionally understand some of it. And I often recognized or even anticipated stuff in the Orthogonal books as the Orthogonal equivalent of, say, the quantum-theoretic reason why identical fermions can't be in the same quantum state. So I'm about as close to the audience of this book as you can be without an actual degree in physics.But quantum theory makes for *really* s***ty dialog. In particular, quantum theory isn't particularly clear to say in English. It needs to be said in mathematics. The author does say it in mathematics, at length, on his web site. Some of my favorite math, too — Riemannian geometry and quaternions — and I still haven't gotten the energy together to go slog through it there. The dialog was pretty discouraging.And characters fumbling around with half a dozen alternate theories and problems … well, that *is* real science. Actually it's curst quick science if it's *only* half a dozen. Still, in the course of a chapter, the characters might easily go through a pile of alternate physics, most of it wrong. I gave up trying to follow it pretty fast. I just skimmed for things that looked familiar from real-life quantum theory.Anyways, that makes up the heart of the book, and it's, well, as tedious as anything I've read in fiction since thirty-page monologues on economic theory, say.Now, there *is* a story going on too, and it's a good enough story to keep me going for two books in the trilogy and I'm probably gonna get to book 3 too. But the author's heart is obviously in the alien physics, not in the story.*My* heart was in the alien biology. The people are semi-amorphous blob things, sprouting hands when they need them. We don't really get a clear picture of what they look like. The really interesting, and devastating, thing is the reproductive biology. Women give birth by fissioning into two baby boys and two baby girls. This kills the woman. Men exist as caretakers of the children — and they are evolutionarily tuned to be superb and devoted parents. But this really, *really* does massive and fairly horrible things to the social structure on a societal and personal level. The author does more nibble on this matter too — it's a key issue in one way in book 1, and in a very different way in book 2 — but it always feels like it's about 21st century Western-civilization people suddenly cursed with a devastating reproductive system. The aliens are very very human considering how alien they are.I really wish John Campbell had edited this trilogy. There's a real gem in there, but it needs heavy-duty cutting and polishing before its brilliance really shows.Three + five'-1 spectrum-splayed stars out of five. (Viz. it was about average for books that I think are worth finishing, but very imaginative.) Which would be phrased as 3×Future + 5×East in the Orthogonal notation.

The book goes into this universe's interesting physics in much the same way as the last - watching characters make discoveries about the nature of the world around them in ways that help drive the core of the plot. While the last book set up a lot of the grand framework - their equivalent to relativity and basic particles. This one goes in depth into the nature of matter and how it interacts with the world's version of photons.The parts dealing with biology were interesting - because it works at a higher level, it isn't so confined to the nitty gritty details of physics, and gives Egan room to play around with creating interesting ideas without the having to worry about how they follow from the laws of physics. This and the effects of living for generations in a ship with limited resources and no foreseeable end to the journey provide a good and interesting break from the physics lectures.The only annoyance was that the diagrams don't always render well on a kindle. Details that were lighter were in too pale a shade of gray. They also don't scale with font size, so when I turned up the size in low lighting, the text on the diagrams was still tiny.

I'm waiting quite impatiently for the third and final installment. This is real science fiction. This is alien biology, alternative science, and all in a universe with completely different laws of physics. I'm so glad I read it.

An excellent story, but intimately intertwined with real math for the physics of a universe that is not quite like ours. You can read the story without the physics, but if you can handle some moderately sophisticated math, this book becomes something I have never seen before. One day, when everyone can download the relevant mathematics, all science fiction will be like this.

As with the first novel in the series, there is a heavy focus on the physics of Egan's orthogonal universe, complete with numerous diagrams. But there are also interesting characters whose lives depend on figuring out the rules and implications of those physics, and who face the challenges of relationships and politics that are familiar even with a radically different biology than ours.

In the second installment of the Orthogonal trilogy, Egan delivers some true science fiction. Although the story itself is quite compelling - there are interesting (and depressing) aspects of characters and society - the core of this book is the fictional science, most of all the physics. After the first book gave us all of the classical physics, this one contains the quantum physics. We follow the characters that discover this worlds laws of nature, but the real core of the book is the actual fictional science. Just to give you an idea: this book has (among others) an appendix on quaternion algebra, which plays a central part in the story. So if you don't feel any love for physics this series, and this book in particular, is probably not a good read. But for those of us who enjoy fictional science, this book is probably unmatched (or should I say peerless) in all of literature.All of this is wrapped into a story that I found quite compelling. I won't say anything more concrete, although for those who have read part one of the trilogy, even the title is enough to give away what happens in this volume. It is a fine read in and for itself, but the real purpose of this volume two is to provide the setup for the spectacular finale of the trilogy.

There was tape on the book that I dislike

This book is not "unputdownable", because every now and again you have to put it down and ponder. The physics and maths seems right to me , as a non mathematician , and the way he leads the folk from one discovery to the other ( from antimatter to lasers to spintronics) is brilliant - why can't the textboks be writen like this ?, I finally understand why electrons need to rotate twice to get to the same position ( 4 dimensional vector addition ).There's the odd quibble - population size on the mountain space-ship must be small enough everybody knows everyone else , so the politics arising from the biology discoveries didn't ring true to the same extent, but gave the story the needed momentum .Physical resources must be limited, and a lot of precious air seems to be being used up profligately , but these are small potatoes - this is hard science fiction written by someone who takes no prisoners . Only one question - when is the nextone coming out?

This sequel maintains the momentum of the "Orthogonal" series. We are now a few generations on from the original book, and Greg Egan gives us a mixture of adventure, theoretical physics and discoveries in other areas. He generates a pervasive sense of tension, as a need to limit population growth among creatures who normally give birth by having the female split into four leads to females having to starve themselves to hold off from giving birth. How various characters try to overcome this provides one of the novel's sub-plots, along with the discovery of the Orthogonal Universe's analogue to quantum wave mechanics.Greg Egan has put a lot of thought into developing the Orthogonal Universe, and this book has certainly included several significant plot developments. I withheld a fifth star because so much of the book is made up of conversations where different scientists try to persuade their colleagues of their new ideas - these sections would probably be of interest to physicists, but rather hold up the story.So I'd recommend this book, with mild reservations, to anyone interested in real science fiction. with challenging ideas intersecting with thrills and drama.

Awesome trilogy. Sometimes the science went over my head but the characters and the narrative are totally immersive. Highly recommended.