Goodreads helps you keep track of books you want to read.
Start by marking “The Eternal Flame (Orthogonal Trilogy, #2)” as Want to Read:
The Eternal Flame  (Orthogonal Trilogy, #2)
Enlarge cover
Rate this book
Clear rating
Open Preview

The Eternal Flame (Orthogonal #2)

3.87  ·  Rating details ·  531 Ratings  ·  53 Reviews
Greg Egan’s The Clockwork Rocket introduced readers to an exotic universe where the laws of physics are very different from our own, where the speed of light varies in ways Einstein would never allow, and where intelligent life has evolved in unique and fascinating ways. Now Egan continues his epic tale of alien beings embarked on a desperate voyage to save their world . . ...more
Hardcover, 328 pages
Published August 26th 2012 by Night Shade Books
More Details... edit details

Friend Reviews

To see what your friends thought of this book, please sign up.

Reader Q&A

To ask other readers questions about The Eternal Flame, please sign up.

Be the first to ask a question about The Eternal Flame

Community Reviews

(showing 1-30)
filter  |  sort: default (?)  |  Rating Details
Oct 23, 2012 rated it liked it
Shelves: e-books, read-2012
3 Stars

I loved Egan's Orthagonal book one, and was really looking forward to this release, but I was left very unsatisfied. For over half this book nothing really happens other than one major "kidnapping" and page after page of analysis and discussion on the physics behind the Luxagens...diagrams and quizzes included. I love hard science fiction, and I loved the way that Egan interwove it with the action in the first book. But, in the Eternal Flame, there is no action other than you turning the
Jan 09, 2012 rated it really liked it
Shelves: sci-fi, my-collection
This book is a marvel of a meticulously detailed exploration of the implications of a universe based on a different physics to ours. Egan has clearly thought through his plot with great care as his protagonists unpick the underlying structure of their reality. The physics unfolds as all is revealed - but too neatly, too patly - it feels as though the story is merely a vehicle for the science.
The numerous physics discussions complete with graphs is rather daunting and I confess that I did not ev
I finished The Eternal Flame by Greg Egan and it was excellent; maybe not as groundbreaking as The Clockwork rocket but a top 10 of mine (kind of in my 2nd tier now at around 4-9); there was no dominant character like Yalda and the universe is now familiar, but still lots of great stuff and I am really curious where it will go in volume 3 (Mr Egan gave a hint in a comment to his blog post on FBC when asked a question by someone).

Quantum mechanics, antimatter and new biology; lots of diagrams, so
Tudor Ciocarlie
Dec 14, 2011 rated it really liked it
Even if The Orthogonal Universe remains one of the most fascinating SF creations, The Eternal Flame is not the formidable book that The Clockwork Rocket was, because of the absence of a character like Yalda and the herculean effort that the reader must make in order to relate to extraterrestrials on a ship in a strange space in a completely different universe.
Ben Lavender
Jan 18, 2015 rated it did not like it
Shelves: didn-t-finish
Didn't finish book 2.

I didn't love book 1, and I bought this one on a whim before hopping on a plane. I just can't get into it.

Physics in this world are different. Varying speeds of light, orthogonal matter, time travel. We follow this universe's Newtons, Keplers and Maxwells experiment and build the rules of physics for this new world. Throw into it a lot of consternation about a different way to breed, and our intrepid scientists are also working on how to make this biological process work bet
Jul 02, 2013 rated it really liked it  ·  review of another edition
Shelves: read-in-2013
The following will include spoilers for The Clockwork Rocket.

A universe where parts of the spectrum of light travel at different speeds. A race where mothers cannot exist. Vector diagrams. They’re overused, but I’ll use them anyway: Egan is nothing if not ambitious and audacious.

A warning: the same issues that pertained to Clockwork crop up here. It is most definitely not a book that will work for everyone. You have to fall within a fairly specific range of readers: either someone who really en
Jul 12, 2017 rated it it was amazing
Must read for everyone related to academia or remotely interested in sci-fi.
Contrary to other reviews, school-level understanding of physics, math and evolution should be enough for you to enjoy it.
Soh Kam Yung
Dec 30, 2012 rated it really liked it  ·  review of another edition
Shelves: sf-and-fantasy
A great follow-up to "The Clockwork Rocket". While that book covers the 'Newton' era of discovery (basic laws of energy, light and motion) for the universe created by Egan, this one throws in the equivalent of Einstein and Mendel over the discovery of their version of quantum theory and of reproduction.

In this book, the descendants of the people who launched The Peerless on a voyage of discovery to save their world are facing social and physical problems. Their procreation process involves the f
Dec 28, 2014 rated it it was amazing
Pleasantly surprising. I found this in the bargain bin of a used book store and since I have enjoyed some of Egan's short stories, I bought it. However, when I started reading it, I realized it was the second of a trilogy. Also, some of the reviews were less than enthusiastic about the physics (including diagrams) that were part of the storyline. Anyway, the book pretty much hooked me right at the beginning with a very intense scene. As I read, it became apparent these were far from human. For i ...more
Jun 28, 2012 rated it it was amazing
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 acti ...more
David Raz
I gave the first book four stars, and I really wanted to like this one more.
Instead, what the Orthogonal Trilogy makes me understand, and this understanding goes stronger from book to book, is that real good hard core science fiction is not only about inventing a universe and exploring the implications of what you invented. It is actually also about hiding the seems and making you forget that there is a strange universe behind it at all. In the Orthogonal Trilogy instead of the fabric, we get t
May 15, 2017 rated it it was amazing
Tw pregnancy/reproductive body horror, violent misogyny by antagonists

For better or worse, it's more of the same as the first book. I loved it, but not for everyone.
Dark Matter
Jan 12, 2014 rated it it was amazing
Shelves: science-fiction
This and more reviews, interviews etc on Dark Matter Zine, an online magazine. This review was written by Rebecca Muir for Dark Matter Zine.

The Eternal Flame is the second book in Greg Egan’s Orthogonal trilogy. Once again, he has written an amazing book. The Eternal Flame is as rich and complex as the first book, The Clockwork Rocket.

If you have not read The Clockwork Rocket, I would recommend getting hold of a copy of that first. The story in The Eternal Flame is
Mar 18, 2017 rated it really liked it
This one is a little more complex than the first book in the series, and focuses thematically on the process of scientific discovery and, maybe even more strongly, on the effects of technology on society.
May 17, 2014 rated it it was amazing
Shelves: science-fiction
I loved this book. In fact, the whole world that Egan has created is wonderful. The world is like our own, but with one simple change. In our world, the metric of spacetime looks locally like ds^2=dx^2+dy^2+dz^2-dt^2, with the speed of light set to 1 and with the space as positive convention, both of which are optional. In the world of the Orthogonal trilogy, though, spacetime looks like ds^2=dx^2+dy^2+dz^2+dt^2. This makes an amazing difference, and one that even most physicists certainly haven ...more
Jan 01, 2017 rated it really liked it
Yes, this is a worthy sequel. If you liked the first book and haven't read this, you should quit reading reviews (just be aware that if the somewhat gratuitous chapter 33 breaks the flow for you and you don't want to skip ahead, appendix 3 might help).
If you didn't read or like the first book, you're wasting your time here as this is very much a continuation.
Now that's out of the way...

One difference with the first book is that there are several POV characters and that the shifts between them ca
David Harris
Dec 09, 2012 rated it it was amazing  ·  review of another edition
This has been a hard review to write. "The Eternal Flame" is a very particular type of book, less a story than an extended physics lecture - the physics in question being different from that of our own universe, but perfectly consistent and worked out in great detail by Egan. In places it reads like "The Feynman Lectures on Physics" restated as a Socratic dialogue. I have a physics degree and found sections pretty tough going. There isn't a lot of plot, and the characters are fairly rudimentary. ...more
Apr 15, 2015 rated it really liked it  ·  review of another edition
At this point, I have lost track of the physics. I'd like to blame it on the long gap between reading this and reading the first book. I can see that they are developing their version of quantum mechanics (among other things), but I admit to skimming a lot of the explanations. That said, though, the book is still pretty good! The social commentary which was already present in The Clockwork Rocket continues.

It's surprising to me that you could use "aliens" reproducing via bifurcation to illustra
Feb 01, 2014 rated it liked it
"The Eternal Flame" is the second book in the Orthogonal Universe series by Greg Egan and it is going to restore the faith of every mathematician, physicist and experimental biologist in the intellectual curiosity of the human race. The human race will just have to go along with the joke. We need these guys. :-)

Exactly like "A Clockwork Rocket" and somewhat like his "Permutation City", the author builds a universe based on a simplified model of physics. He makes experimental physics part of the
Jun 29, 2013 rated it really liked it
This one follows directly where The Clockwork Rocket left off. Everything I said in my review of that book applies here too. But Egan's "Orthogonal" universe does get deeper and more interesting here, as the scientific and cultural revolutions progress in the way that they do. As a world-builder, Egan is really in top form here.

Most of the physics went over my head, sadly. The feeling I had in those sections reminded me of reading The Difference Engine. Being unable to process all the informatio
Jonathan Scotese
This sequel delivers more of the same. If you loved the first one you will love this one, if you have hopes that there will be less diagrams and less focus on the physics of this universe, you will be disappointed.

The book does not pick up immediately where the first left off, instead it starts several generations later. The ship has begun shifting in culture from the home planet. I'm looking forward to how much further the culture will have drifted in the third one and how the return of the shi
Yanni Cooper
Dec 10, 2012 rated it really liked it  ·  review of another edition
Are you a Schmoht Guy!? Do you have brains just oozing out left and right? Do you ever think maybe you're TOO smart? Here's a book for you. With a few tiny changes to the basic math of the universe, relativity, never an easy to understand thing in the first place, because even more wildly unfathomable. Spoilers follow: In the first book an entire mountain was launched into space, and sent away from the planet at light speed, because the way relativity works in this universe that would give the m ...more
Apr 13, 2015 added it
Book Two of the Orthogonal Trilogy explored further Greg Egan's fascinating wholly other Cosmos based on radically different physics to our own. All based on a simple change to the way space and time are related to each other. The alien people of his other World are radically different to us - e.g. child-birth causes the mother to divide into two or four male/female children, thus is a kind of death; they have eyes on the back of their heads and can extrude limbs as required; they need air for c ...more
Pontus Gagge
Sep 19, 2012 rated it really liked it
Shelves: e-books, hard-ish-sf
An interesting continuation of the trilogy, in much the same style as the first. Plotwise, it may suffer a bit from the middle book syndrome, although to be fair, the science is still the main character, and its process of being extended into the analogues of quantum mechanics and neurobiology is lovingly captured. I'm not sure if Egan will be able to fill in the gaps in the alien biology as convincingly as he does the alien physics: but for now, I'm reserving judgement, since the discovery proc ...more
Nov 30, 2014 rated it liked it
Readable, but the parts I enjoyed (the character's discovery of their world's physics & biology) felt thinned out by the political narrative. Would have liked it more as a short story or novella which cuts down the story & characters in favor of hard science meat.

To be clear, I'm not looking for a textbook without any narrative content to break up the hard science. On the contrary, IMO the best Egan works ("Permutation City" and "Diaspora") organically bring together a compelling storyli
Apr 28, 2012 rated it liked it
Not Egan's best, though his unusual approach (by which I mean teaching physics) at least saves this book from being totally bland, which is a criticism I realize not everyone will share. Egan can be an acquired taste.

The reason this is getting three instead of four stars is because this felt like a weaker book than the first in the series. The setting feels more familiar, in the sense of a pair of shoes after the novelty wears off, and there really is no single protagonist or strong plot to tie
Nov 23, 2016 rated it really liked it  ·  review of another edition
This is one of the toughest SF books I've read; it contained even more science and graphs than the first volume. Coming to grips with the physics and biology of a completely different universe from ours was daunting and figuring out how the theories involved work in our own universe is quite a challenge, especially if you're more of a humanities kind of reader. In addition to this hard science, there is enough in the novel to keep the reader interested in this strange civilization that goes thro ...more
Ronald Lett
Nov 10, 2012 rated it really liked it  ·  review of another edition
Recommends it for: Hard science fiction fans with a science degree under their belt
Shelves: science-fiction
Another satisfying romp through this strange alternate universe with positive definite spacetime metric finds the residents of the Peerless finally discovering the quantum mechanics of their world, without the aid of separate electric and magnetic fields! However, this is overshadowed by the building plot of the extreme gender-based inequality that finally explodes into the unavoidable violent confrontation between the sexes. Egan balances both sides of the tale well, but the physics side of thi ...more
Jul 17, 2015 rated it liked it
A decent, but not captivating, continuation of book 1. I found the science in this one considerably harder to follow, just smiling and nodding along instead of really thinking it through, but perhaps a real physicist would be able to appreciate it more. (On the other hand, perhaps a real physicist would immediately think it was all bogus... I found the negative/infinite temperature bits pretty suspicious.) The book also features a subplot that's a pretty transparent allegory for women's reproduc ...more
Benjamin Edwards
Dec 19, 2014 rated it it was amazing
I like generation following books. In this sequel to the clockwork rocket, we look in detail into the lives of people of the third generation of travelers. Overpopulation leads to single gender famine and infanticide. They make great technological advances in this book, some of which could destroy or save their society. Their women die in childbirth, more specifically they become their children, 4 of them. Their population threatens to exceed their carrying capacity, so the women starve themselv ...more
« previous 1 3 4 5 6 7 8 9 next »
There are no discussion topics on this book yet. Be the first to start one »
  • In the Mouth of the Whale (The Quiet War, #3)
  • The Fourth Wall (Dagmar, #3)
  • Fate of Worlds: Return from the Ringworld (Ringworld, #5)
  • Ashes of Candesce (Virga, #5)
  • Any Day Now
  • Empty Space (Empty Space Trilogy #3)
  • The Island and Other Stories
  • The Thousand Emperors
  • Slow Apocalypse
  • Bullettime
  • Castillon (Tom Swan and the Head of St George, #1)
  • Worldsoul (Worldsoul, #1)
  • Zeuglodon (Narbondo, #6)
  • Hypothetical Lizard
  • Mirror Space (Sentients of Orion, #3)
  • States of Injury: Power and Freedom in Late Modernity
  • Rapture (Bel Dame Apocrypha, #3)
  • Japan: A Reinterpretation
Greg Egan specialises in hard science fiction stories with mathematical and quantum ontology themes, including the nature of consciousness. Other themes include genetics, simulated reality, posthumanism, mind transfer, sexuality, artificial intelligence, and the superiority of rational naturalism over religion.

He is a Hugo Award winner (and has been shortlisted for the Hugos three other times), an
More about Greg Egan...

Other Books in the Series

Orthogonal (3 books)
  • The Clockwork Rocket (Orthogonal Trilogy #1)
  • The Arrows of Time (Orthogonal Trilogy, #3)

Share This Book

“Isn’t that what the Peerless is for? Anything too difficult for the home world?” 1 likes
“If you’d managed to force it open, you would have made a direct path between the interior of the Peerless and the void, which is something we try to discourage.” 1 likes
More quotes…