History Literature / Orthogonal

** Since DeathBySex and DeathByChildbirth always applies (for the women), men typically raise their children alone or with the help of their own fathers. Thus, women are widely (but not universally) considered unfit for childrearing.

* DeathBySex: The immediate consequence of the above.

* StoryboardingTheApocalypse: In ''The Clockwork Rocket'', once Yalda predicts that a Hurtler will destroy the planet, her student Eusebio explicitly asks her to do this. [[note]]What he really wants is a timeframe, so that he can judge whether the idea of the GenerationShip is worth pursuing, or if [[KillEmAll they're all going to die]] [[ShootTheShaggyDog too soon for it to matter]].[[/note]]

* ShootTheShaggyDog: [[KillEmAll Everyone on the ship starving to death]] due to overpopulation and insufficient crop yields (and therefore rendering the majority of the trilogy, if not the whole thing, pointless) is outright stated to be a possible ending to the second book, which provides the motivation for the biologists and horticulturists in their attempts to defy it.

A characteristically [[MohsScaleOfScienceFictionHardness Hard Science Fiction]] {{Trilogy}} by Australian author Creator/GregEgan. Consists of:

* Mohs/OneBigLie: But the Lie is such a fundamental one, and is extrapolated on such large scales, that it leads to a universe that can feel more like Mohs/ScienceInGenreOnly.

* UnfortunateNames: Mention is made of a natural philosopher from ancient times, who is very obviously this world's answer to Aristotle, who had the name of Meconio. For those readers without a medical background, ''meconium'' is [[spoiler:fetal feces]]. It is quite clear what the writer thinks of Aristotle and his anti-empirical philosophy, though since we only hear of Meconio through conservative characters who treat his word as the gospel we don't actually know whether a MisaimedFandom occurred in-universe.

** And even weirder [[note]]or, depending on your perspective, completely and utterly normal[[/note]]: Near the end of ''The Eternal Flame'', the biologist half of the EnsembleCast develops a way to [[spoiler: induce childbirth that produces only one child, does not kill the mother, renders her sterile for the purposes of traditional (fission) childbirth, ''and'' is shown to be repeatable in the final book, ''and'' can produce male children. In other words, they can more or less reproduce [[NotSoDifferent just like us]]]].

* SuspendedAnimation: Because of the universe's MinovskyPhysics, reversed TimeDilation is in effect: Traveling fast enough will essentially cause [[TimeStandsStill Time to Stand Still]] from your perspective. The GenerationShip uses this to effectively suspend their entire [[DoomedHometown Doomed Home Planet]] while they figure out a way to SaveTheWorld.

The plot follows a group of {{Shapeshifting}} StarfishAliens faced with an impending [[ApocalypseHow/ClassX3 Class X-3 Galactic Destruction Apocalypse]] (sort of; it's complicated, see the ApocalypseHow example below for details) caused by incredibly destructive {{Antimatter}} meteorites from AnotherDimension. They realize they can't do anything to save themselves with their current technology, so they build a GenerationShip to fly into that alternate dimension, where they will have [[TimeStandsStill all the time they need]] to advance their technology to the point where they will be able to return and SaveTheWorld.

* AliensNeverInventedTheWheel: Justified with electronics; because of this universe's physics, basic electronics are not completely impossible to construct, but it is highly unlikely that sentient beings would ever discover the principles that would make it work without a lot of luck or help. [[spoiler: Between the second and third books, though, they do invent "photonics", which serves pretty much the same function as electronics, except that it works by using photons instead of electrons]].
* AllThereInTheManual: Given that nearly half the trilogy consists of TechnoBabble ExpoSpeak, it's hard to believe that Egan has posted multiple essays on his website that delve even further into the workings of ''Orthogonal'''s universe -- and yet, [[http://www.gregegan.net/ORTHOGONAL/ORTHOGONAL.html here they are]].

* {{Antimatter}}: Played relatively straight and occasionally referred to by name, but usually just called "[[TitleDrop orthogonal]] matter". When interacting with matter that originated in a cluster traveling in a different direction through the time-dimension, it's important to take into account exactly which direction it was traveling. Depending on which "time direction" you approach it from, it could either be ordinary harmless matter with MerlinSickness (i.e., experiencing time backwards from your perspective), or it could be MadeOfExplodium and annihilate you in a massive explosion as soon as you touch it.
* ApocalypseHow: A [[ApocalypseHow/ClassX Class X Planetary Destruction]] is anticipated early on when the characters realize their planet is in danger from {{Antimatter}} meteorites, before the characters realize that they are actually facing a [[ApocalypseHow/ClassX3 Class X-3 Galactic Destruction]], because an entire Antimatter ''galaxy cluster'' is en route to collide with their own galaxy cluster. [[note]]It could even be considered a [[ApocalypseHow/ClassX4 Class X-4 Universal Destruction]]; depending on your perspective, clusters of matter that share an [[TitleDrop Arrow of Time]] could be considered analogous to either galaxies or universes in a multiverse. The most technically correct approach would be to make them either galaxies or [[ExactlyWhatItSaysOnTheTin galaxy clusters/superclusters]], which would make the impending disaster a Galactic Destruction.[[/note]]

* BizarreAlienPsychology: Mostly averted with some notable exceptions.

* BizarreSexualDimorphism: Mostly averted. Males and females don't look too different from each other, with a few exceptions. In fact, at one point a character witnesses an animal giving birth to a solo under unique circumstances, so there is no way to predict that the baby will be a female, as with all other solos. He realizes after the animal is born that he has no idea how to identify its gender without a co to compare them in size (the female would have been larger).
** Even when they are not solos, women are generally larger than men, justified in that the extra mass is needed to successfully split into four healthy children. As a result, women are generally stronger than men and thus do most of the manual labor. [[note]]Because of this, for most of ''The Clockwork Rocket'', before the launch of the ''Peerless'' and the subsequent retooling of societal norms, men tend to take center stage on intellectual pursuits. Educating women is widely considered a waste of time, since they have much shorter lifespans and their knowledge is not passed on when they fission. It's mentioned in passing that these gender roles were reversed at some point in the past, when it was believed that a woman's knowledge ''did'' get passed on to her children, while knowledge taught by men only went skin deep.[[/note]]

* CallASmeerpARabbit: ''Orthogonal'' takes place in a universe with entirely different laws of physics from our own, and thus predictably BizarreAlienBiology. It still uses common words like "plant" and "vole" to describe things that are roughly analogous. [[note]]Never mind that plants gain energy by emitting light rather than absorbing it, and voles are just a smaller and less evolved species of {{Shapeshifting}} [[StarfishAliens Starfish Alien]] than the protagonists.[[/note]]
* CallARabbitASmeerp: Almost entirely averted, but played relatively straight with "luxagens", which are analogous to atoms in RealLife, and [[spoiler: "photonics" in ''The Arrows of Time'', which are analogous to electronics]]. Possibly justified in that they function fundamentally differently in several ways, but in this universe, what doesn't? Possibly another (extremely mild) example: Space, as in, outer space, is ''never'' referred to as such. It is always referred to as "the void".
* ClarkesThirdLaw: Reconstructed and frequently discussed. The entire point of the ''Peerless''' journey is to have an indefinite amount of time to develop sufficiently advanced technology that will let them SaveTheWorld from the impending [[EarthShatteringKaboom Cluster-Shattering Kaboom]], even though they have no idea what kind of technology it will be, or even if the people that return will have evolved enough to no longer be recognizable as the same species as those who left. See also TheSingularity, below.

* ConvenientlyClosePlanet: Mostly averted throughout the trilogy, but there is one straight instance and one notable aversion.
** Played relatively straight with a Conveniently Close Asteroid. A large part of ''The Eternal Flame'''s plot revolves around a BigDumbObject known as [[ShapedLikeItself the Object]], a large chunk of [[TitleDrop orthogonal]] matter that drifts close enough to the ''Peerless'' for the protagonists to travel to it. The characters lampshade the trope by realizing that the Object is one of the greatest opportunities they've had since the launch, because if they lose it, they will probably never come this close to another. [-(Partially subverted in that it ''does'' take the crew of the ''Gnat'' several days to reach it.)-]
** Averted in ''The Arrows of Time''; the roundtrip journey from the ''Peerless'' to Esilio and back takes ''twelve years'' from the perspective of the travelers, but thanks to the justified TimeyWimeyBall, it only takes four years from the perspective of the ''Peerless''.

* DeathByChildbirth: Universally played straight and justified by the fact that natural childbirth consists of the mother fissioning into four children.

* DeathBySex: Universally played straight and justified by the fact that sex triggers immediate reproduction, which consists of the mother fissioning into four children.
* DepopulationBomb: Discussed by opponents of the [[spoiler: reproduction-inducing experiments]], who hypothesize that if [[spoiler: survivable single childbirth [[AlwaysFemale always results in female children]]]], it will lead to the [[{{Gendercide}} eradication of the male gender]].

* ExpositionDiagram: Even for Egan, ''Orthogonal'' has an unusual amount of these. On average, at least two or three appear in almost every chapter, especially in the second book. More or less justified in RealLife, because the near-constant TechnoBabble would be even more difficult to follow without them.

* {{Farmboy}}: Yalda in ''The Clockwork Rocket'' grew up on a farm and went into academia against her family's wishes. Several characters in ''The Eternal Flame'' are also characterized as farmers, Tamara probably being the most notable. {{Justified|Trope}} in that the GenerationShip wouldn't be able to subsist without a great deal of highly-specialized agriculture, so the science of [[InSpace space farming]] is vital to the ship's inhabitants.
* FasterThanLightTravel: Thanks to the way spacetime works, there is no universal speed limit, and achieving FTL speeds is a surprisingly simple matter. Of course, you [[TimeDilation stop moving forward through time]] and end up in AnotherDimension, but that has its own useful applications.
* FlingALightIntoTheFuture: A very unusual example. The GenerationShip's mission is to accelerate into AnotherDimension, so that, from their perspective, time will stop for the homeworld. This will allow the crew all the time they need to develop technology and science to the point where they'll be able to return and SaveTheWorld. Thus, the ship may drift through space for an indefinite amount of time, but no matter how long they have, when they return, only four years will have passed on the homeworld.
* ForScience: Defied in ''The Eternal Flame'' by the Council mainly due to not having InfiniteSupplies, and further defied by a few extremists due to ScienceIsBad, but otherwise played straight and thoroughly justified by the fact that the characters initially have no idea what they need to study in order to SaveTheWorld, so they pretty much just research anything and everything that comes to mind. The hope is that if they study enough subjects, something will lead to a revelatory breakthrough. This includes light, agriculture, biology, the fundamental building blocks of matter, and more. [[note]]Granted, some of these studies are geared more toward ensuring that they don't [[ShootTheShaggyDog all starve to death due to overpopulation before accomplishing anything meaningful]], but the trope holds.[[/note]]

* JustBeforeTheEnd: The trilogy consists entirely of an attempt to defy this trope. The GenerationShip's mission is to suspend their [[DoomedHometown Doomed Home Planet]] Just Before The End, and unsuspend it once they are able to figure out a way to avert the disaster.
* KillEmAll: Discussed. It's outright stated that everyone on the ship starving to death due to overpopulation and insufficient crop yields (and therefore [[ShootTheShaggyDog rendering the majority of the trilogy, if not the whole thing, pointless]]) is a possible ending to the second book, which provides the motivation for the biologists and horticulturists in their attempts to defy it.

* LadyLand: Discussed by opponents of the [[spoiler: reproduction-inducing experiments]], who hypothesize that if [[spoiler: survivable single childbirth always results in female children]], it will lead to the eradication of the male gender.

* MaternalDeathBlameTheChild: Surprisingly averted. Surprising, because [[spoiler: for most of the first two books]] it is universally accepted that a mother is utterly incapable of surviving childbirth -- so DeathByChildbirth ''always'' applies. This is almost universally accepted as a fact of life.

* MoreThanThreeDimensions: Played as straight as can be, and thoroughly [[JustifiedTrope Justified]]. Egan ''rewrites the laws of physics'' to create an internally-consistent universe where there really ''are'' four spatial dimensions, one of which is perceived by the protagonists as time. An (oversimplified) explanation for why time seems so different from space is that the protagonists' momentum through the dimension of time is so great that it's impossible to change trajectory without technological assistance.

* NarrativeShapeshifting: A subtle example. One application of the StarfishAliens' {{Shapeshifting}} ability is that they write by raising shaped ridges on their skin, and then dusting their skin with dye and pressing it to paper for posterity. But when characters can't hear each other, either because the environment is too noisy or because they are in the [[SpaceIsNoisy silent vacuum of space]], they can also communicate by "writing" notes on their skin for others to read.
* NoWomansLand: Discussed. When people start panicking about the prospect of {{Gendercide}} and a subsequent LadyLand, one character points out that even if the biological gender currently called "men" no longer existed, women would then fulfill all the societal roles performed by men, which would force them to redefine the gender as a concept. He ends by slyly suggesting that [[{{Gendercide}} eradicating all the men]] might actually end up creating a NoWomansLand.

* OneTrueLove: Justified by their biology: A set of cos is biologically optimized to mate with each other, and most such couples spend their lives together as a socially acceptable cross between brother/sister and husband/wife. Co-steads, non-related couples who have decided to mate, are also examples to a lesser degree. Averted on several occasions, though, including [[spoiler: Tamaro's imprisonment and near-attempted-murder of Tamara, which results in Tamara's estrangement from the entire family]] and [[spoiler: Tamara's new co-stead explicitly telling her that he will completely abandon her if he believes that she never intends to mate with him, even if she has children by another (survivable) means]].

* ParentalAbandonment: Utterly justified by the fact that DeathByChildbirth is universal for women. Discussed a few times, and [[spoiler: ultimately defied by the development of a procedure that allows women to survive childbirth]].

* ProfessorGuineaPig: Played straight at least three times.

* RapeIsASpecialKindOfEvil: Discussed a few times. Thoroughly justified by the reproductive system of the species: Sex immediately induces reproduction, and the females reproduce by fissioning into four children. Logically, this means that it is impossible to commit rape without ''also committing murder''.

* ShapeshifterModeLock: A relatively minor example. When Carlo's hand starts spasming uncontrollably during the light experiment, he tries to reabsorb it into his body, but can't. It's implied that he was just so [[BodyHorror viscerally repulsed by the phenomenon]] that he couldn't make himself absorb the hand, rather than actually being physically incapable of doing it, but it still qualifies.

* TheSingularity: Discussed. The entire point of the ''Peerless''' journey is to have an indefinite amount of time to develop sufficiently advanced technology that will let them SaveTheWorld from the impending [[EarthShatteringKaboom Cluster-Shattering Kaboom]]. Several characters wonder aloud just how much time that will actually be, and whether the returning travelers will bear any resemblance to their ancestors when they return.

* SpaceAgeStasis: A small-scale, justified, and very unusual example that lasts about three years and [[ItMakesSenseInContext Makes Much More Sense In Context]]: In ''The Arrows of Time'', when the inhabitants of the ''Peerless'' [[spoiler: construct a messaging system that allows them to send messages back in time]], it results in the inability of ''anyone'' to come up with ''any'' new technological or scientific advances. This is pretty significant when you consider that up to this point, they have progressed from technology based on clockwork and combustion engines (or the equivalent thereof) to photonics (read: electronics) and nearly-[[PerpetualMotionMachine Perpetual Motion Machines]] that are powered directly by light -- all within six generations of the launch. [[labelnote:SPOILERIFFIC note]]The lengthy explanation given for this is as follows: In this universe, time travel is relatively easy, because acceleration in space changes the direction through which you travel through time. Accelerate a ''lot'', and you'll go sideways; accelerate even more, and you'll go backwards. Continue accelerating and you'll eventually come full circle and be traveling "normally" again. But since the universe is a closed loop and time travel is just a matter of course, obviously everything has to be mutually consistent. [[StableTimeLoop Stable Time Loops]] are really no big deal -- but a StableTimeLoop containing an ontological paradox (at least, one more complex than a basic exchange of obvious or useless information), while not patently impossible, is astronomically unlikely, for the same reason that [[MonkeysOnATypewriter dumping a truckload of pebbles onto the ground is astronomically unlikely to produce the complete works of Shakespeare in Braille]]. Basically, anything that is created entirely inside of such a loop is an example of ordered complexity arising from chaos. It's ''physically possible'', it's just unbelievably improbable. Likewise, if a StableTimeLoop involved, say, a physicist receiving a message from herself in the future that explained a revelation about the curvature of spacetime, it would mean that no one had actually come up with the idea; the completed thesis simply coalesced out of the chaotic interactions of matter and energy and forces in the universe. So, since there's no reliable way to ensure that any new discoveries ''wouldn't'' be sent back in time with the messaging system (or rather, it's ''extremely improbable'' that people would ''not'' find a way to send those messages -- notice a pattern?), thus creating an ontological paradox and a StableTimeLoop, the simplest way for the universe to keep itself internally consistent is to render innovation impossible as long as the system exists.[[/labelnote]]
* SpaceIsCold: Justifiably inverted. The StarfishAliens don't seem to need to breathe, and the lack of pressure isn't an issue, so their only risk during exposure to the vacuum of space is that the lack of cooling air can cause them to overheat and die within minutes. See also SpontaneousHumanCombustion below.
* SpaceIsNoisy: Predictably (considering the author) averted, but the aversion is really only significant in that it forces an interesting use of the NarrativeShapeshifting trope. Because space cannot carry sounds, the characters must devise innovative ways of communicating while outside the ship.

* SpontaneousHumanCombustion: Life in this universe relies on chemical reactions that can and do occasionally get out of control, resulting in dangerous and spectacular instances of this trope. In fact, [[spoiler: the trilogy opens with one]].

** {{Discussed|Trope}} and implied to be played straight by the discussion: The theory of four-space, which states that the dimension of time is ''literally'' identical to any of the dimensions of space and that the universe is a [[WrapAround closed loop in all dimensions]], implies that this is the natural state of the entire universe.
** Partially deconstructed in ''The Clockwork Rocket'', when a character wonders if free will is just an illusion in such a universe, and Yalda explains her opinion of why it's not.
** Fully deconstructed in ''The Arrows of Time''. The main plot is driven by the idea of a messaging system that will allow people to send messages back in time. Cue extensive discussions about why this could not possibly lead to a TemporalParadox.

* StandardTimeUnits: Almost entirely averted, in that time (and mass, and distance) are measured in units invented for the story. However, two of those time units are days and years. It's also implied that a "flicker" is analogous to a second.

* SubspaceOrHyperspace: Not referred to by name, but orthogonal space functions like hyperspace in many ways.
* SuspendedAnimation: Uniquely inverted. Because of the universe's MinovskyPhysics, reversed TimeDilation is in effect: Traveling fast enough will essentially cause [[TimeStandsStill Time to Stand Still]] from your perspective. The GenerationShip uses this to effectively suspend their entire [[DoomedHometown Doomed Home Planet]] while they figure out a way to SaveTheWorld.

* TechnoBabble: [[TitleTheAdaptation The Book]]! Egan tones it down in the third book, though.

* ThemeTwinNaming: Universally played straight, the only exceptions being solos. Cos are named with masculine and feminine forms of the same name, always ending in 'o' for males and 'a' for females. Examples include Carlo/Carla, Addo/Ada, Tamaro/Tamara, and so on.

* TimeDilation: Justifiably inverted by the laws of physics as they apply in this universe. Traveling fast enough will cause you to be traveling through space without moving through time, which [[TimeStandsStill causes time to stop]] for the starting location. It drives the plot: By taking advantage of this phenomenon, the characters have all the time they need to figure out how to SaveTheWorld.
* TimeyWimeyBall: Might be explained away with really, really, ''really'' careful analysis and a pile of diagrams, but in practice it comes across more as a [[JustifiedTrope Justified]] example. Due to the inverted TimeDilation, the plot gets into some really convoluted time travel shenanigans.

* UntoUsASonAndDaughterAreBorn: With highly unusual exceptions, this trope is ''universally'' played straight with ''every birth''. Justified by the biology of the species; when women reproduce, they fission into two pairs of male and female twins. Rarely, one of the pairs might instead be a single female, but males are never born solo, and the solo females are, again, very rare. There are no instances in the book of ''both'' pairs being born as solo females instead, so every natural birth results in at least one pair of twins.

* YouAlreadyChangedThePast: Played with every which way from Sunday except straight -- mostly just because everybody accepts that it would be impossible, so nobody tries.
** [[DiscussedTrope Discussed]]: As mentioned on the main bullet above, as soon as the characters nail down the nature of spacetime, it's pretty much accepted that TimeTravel, while possible (and surprisingly easy), cannot actually change anything that has already happened or been confirmed to happen.
** DoubleSubversion: On Esilio, a planet with MerlinSickness, the crew of the ''Surveyor'' blow up a rock. After the explosion, they find what looks like writing etched into a newly-exposed part of the rock, which seems to be a message from the ancestors (the inhabitants of the homeworld). Because of the planet's MerlinSickness, the message must have been carved at some point in the future. The obvious assumption is that the message means the journey is successful; the ''Peerless'' makes it home, and at some point the ancestors visit Esilio and carve the message as encouragement to the travelers. But Ramiro decides that he wants to have a hand in fate, so he plans to go out and "carve" the message himself. [[spoiler: Tarquinia prevents him from doing so -- and he then realizes that ''she'' is going to carve the message. He spends most of the rest of the book under the impression that she did -- only to discover after the climax that she tried to carve it, but no matter what she tried, the message stayed there, which means that she didn't do it either. The book ends with a subtle implication that a minor character who returns to the homeworld in the epilogue is the one to go back to Esilio and carve the message.]]
** [[InvokedTrope Invoked]]: The ''Surveyor'' returns to the ''[[GenerationShip Peerless]]'' after a long absence to find that the inverted TimeCapsule messaging system (which essentially lets people send email back in time) has been built, but also [[spoiler: mysteriously stops working all at once at a known point in the future. But since no one actually knows what causes the disruption, the crew of the Surveyor realize that if nobody does anything, they are most likely consigning themselves to being hit by a meteor. On the other hand, if they attempt to sabotage the system, they are raising the probability that ''they'' will cause the disruption, which means no one will be harmed. In other words, they know they [[YouCantFightFate Can't Fight Fate]] since the universe is an absolutely StableTimeLoop, but if nobody tries to cause the disruption, then it's almost guaranteed that it's caused by a disaster such as a meteor strike; but as long as no one knows what causes the disruption and ''someone'' is trying to cause it, they are increasing the odds that the disruption has a harmless cause.]]

* CoversAlwaysLie: The cover art for each book in the trilogy depicts the GenerationShip ''Peerless'' as a sleek and sexy CoolStarship, while the actual books describe it as [[ShapedLikeItself looking exactly like what it is]]: A mountain that was hollowed out, reinforced, fitted with rockets, and blasted into space. The cover of the first book is particularly {{egregious}}, as it depicts no fewer than ''five'' such spacecraft. [[spoiler: In fact, a second, ''much'' smaller craft is constructed part of the way through ''The Eternal Flame'', but that's it for the first two books.]]

* SpeculativeFictionLGBT: Most is unusually silent on the subject of LGBT issues and characters (the trilogy instead examines issues of gender equality and women's rights), but by the end of the trilogy, the protagonists' initially two-gendered, male/female species has undergone a {{Singularity}} that has resulted in, among other things, a single-gender race that is explicitly considered neither male nor female.