The Three-Body Problem (三体) is a Science Fiction novel and the first installment of the Remembrance of Earth's Past trilogy by Liu Cixin (the trilogy is occasionally also referred to by the title of this book). It was first serialized in 2006, published as a novel in 2008, and translated into English by Ken Liu in 2014.
In modern day China, Wang Miao is facing a problem: all the foremost physicists in his specialty, nanomaterials, are committing suicide, leaving behind extremely cryptic suicide notes. He's assigned to join a mysterious secret society that may have some answers, but keeps getting distracted by a revolutionary new MMORPG called "Three Body"...and also by the mysterious numbers that appear only in his vision, counting down to a date about fifty days away.
Many years into the past, Ye Wenjie is having a problem: though a brilliant physicist, she was branded a political dissident back during the Cultural Revolution, and was exiled to a lonely military station called Red Coast. However, Red Coast harbors goals far beyond the scopes of the earth, and Ye's personal struggles will have lasting impacts on the fate of the whole world...
The novel is succeeded by The Dark Forest.
- A webtoon adaptation of the same name
- A Chinese cartoon of the same name, by Bilibili
- Three-Body, a live-action TV adaptation, was developed by Chinese entertainment company Tencent Video and premiered in 2023.
- 3 Body Problem, an English-language miniseries, was developed by David Benioff & D.B. Weiss (Game of Thrones) and Alexander Woo (The Terror: Infamy) and is set to premiere on Netflix in 2024.
- Adaptation Expansion: The webtoon adds a considerable amount of material focusing on Shi Qiang, in particular a story arc where he and his team follow Pan Han to Italy.
- All Crimes Are Equal: On Trisolaris, "guilty of anything whatsoever" is synonymous with "due for execution".
- Anachronism Stew: In-Universe. The Fictional Video Game "Three Body" mixes and matches historical figures, locations, and technologies from various eras and locations. For example, the third time Wang logs on, he is greeted by Gregory I, Aristotle, da Vinci, and Galileo in a setting that resembles the High Middle Ages, and Aristotle attempts to burn him at the stake with a Zippo lighter. Repeatedly lampshaded by Wang, who internally comments on the anachronisms.
- And You Thought It Was a Game: The video game "Three Body" is a covert recruitment tool for the ETO.
- Artistic License – Physics:
- The sophon lockdown involves proton-sized computers obscuring all reliable data from the Earth's particle accelerators, thereby ensuring the Earth remains in a Modern Stasis so the Trisolarans can invade. The problem is that, because particle accelerators operate 24/7 for months or years straight, the sophons would need to generate so much obscurity- the equivalent of white noise- that their presence would be detected sooner or later. Rather than forcing scientists to throw up their hands and give up, this would allow them to analyze the sophons more directly. They couldn't remain hidden because, no matter how good of a computer they are, the random and probabilistic properties of the quantum world wouldn't allow them to avoid interacting with something and thus being detected. Moreover, the more time the sophons spend performing confusing behavior in order to foil their own direct examination, the less time they can spend faking data in the experiments directed at basic research.
- The book also suggests only particle accelerators are responsible for fundamental research, and that humans couldn’t build massive supercollider accelerators, Synchrotrons and Linacs, fast enough to match the Trisolaran production capacity. Even if this were true, this would still leave machines like plasma wake field accelerators functional, and this can replicate the same experiments in supercolliders for a fraction of the energy and price. Even sophons couldn't force every device on the planet into lockdown.
- Artistic License – Space:
- The Alpha Centauri system, where Trisolaris is located, is portrayed as three stars orbiting each other in chaotic, unpredictable ways. In fact, it consists of a stable binary pair of stars orbited at a great distance by a red dwarf star.note
- With an orbit that unstable, Trisolaris should have been ejected from its stars (or flung into one of them) eons ago, assuming it was ever able to form at all. This is Hand Waved in-universe, with the planet's continued existence being considered a minor miracle that will finally run out in a mere thousand years.
- Binary Suns: Trisolaris has three suns (hence the name) and orbits them in an unpredictable pattern: sometimes it's orbiting one particular star and has a stable climate (a Stable Era) and sometimes it's orbiting all three at once and has a wildly unstable climate (a Chaotic Era). The transition between one orbit and another can be traumatic due to the gravitational pull and proximity to the suns, and it's not unheard of for such transitions to completely destroy Trisolaran civilization in the process, leaving the survivors to rebuild.
- Celibate Eccentric Genius: Wei Cheng, Shen Yufei's reclusive husband, describes himself as a lazy math genius who had an eccentric way of solving problems and had no interest in women. Even his marriage to Shen Yufei was born out of convenience and a mutual desire to solve the three-body problem.
- Les Collaborateurs: The Earth-Trisolaris Organization is a terrorist group that believes humanity cannot manage its own affairs and deserves to be conquered by Trisolaris. There are two major factions in the ETO: the Redemptionists, who want to set up a Vichy Earth scenario where the Trisolarans rule over a human utopia, and the Adventists, who believe that humanity is wretched beyond repair and should be exterminated.
- Cruel Mercy: The Trisolaran operator who transmits a warning to Earth is not executed for his crime, as he expected (and is the norm for his species), but instead is kept alive so that he will be Forced to Watch when humanity is conquered by the invasion fleet. He turns up again in the epilogue of book two, dying of old age but content that he lived long enough to see Earth and Trisolaris finally make peace, at least for a while.
- Death World: Due to its chaotic orbit around three suns, Trisolaris is a nasty place. When it orbits any one sun, it goes into a Stable Era, during which conditions are actually pretty mild. However, the rest of the time it's being kicked around like a football during Chaotic Eras, where it alternates between broiling heat and freezing cold with absolutely no rhyme or reason at all. On particularly close or distant passes, temperatures may melt rock or drop to near absolute zero. Sometimes, the three suns align in a straight line with Trisolaris at one end, causing everything on the surface to literally fall into the nearest sun. Due to the eponymous three-body problem, all of this happens completely at random, and cannot be predicted at all. The only reason anything lives there at all is that native life adapted to dehydrate indefinitely and then come back when conditions got better.
- Deliberate Under-Performance: Ye Wenjie considers her quick rise through the technician ranks at Red Coast Base unusual, because she doesn't have an engineering background and the corps are supposedly comprised of the best the army has to offer. It turns out that most of them are purposefully not trying too hard in hopes that they'll be transferred out of the remote, top-secret facility.
- Despair Event Horizon: Ye Wenjie falls into despair at the end after she finds out that far from being a morally-superior civilization who can save humanity from its own madness, the Trisolarans suffer from many of the same foibles that she hates in humanity and are in many ways even worse.
- Fictional Video Game: The Three Body game is a VR game and a multiplayer civilization builder. It's set on a world where the climate swings between hospitable stable periods that are optimum for building civilizations, and chaotic periods with an incredibly unpredictable and hostile climate where days are incredibly hot and the sun doesn't always rise in the same direction or at the same time. The way the game is structured is that the goal, as far as anyone can tell, is to build up as advanced a society that they can before an ecological catastrophe inevitably kills them all and the game starts again. Figuring out the pattern of the seemingly random chaotic periods has been a long term goal of players so that they can predict and take advantage of the stable periods. Eventually, Wang (under the screen name of Copernicus) figures out that the world has three suns orbiting each other in a very chaotic pattern, and the planet the game is set on has an even more chaotic orbit, where stable periods are the brief moments where the planet is in a stable orbit of one of the suns before tangling gravity fields cause the orbit to become chaotic again. The "game" is more of a narrative of the history of Trisolaris and a recruiting tool of the Earth-Trisolaris Organization. The game was a condensed history of roughly 19 million years of the cyclical apocalypse and rebuilding of Trisolaris before they eventually had the technology to just abandon the planet.
- Good with Numbers: Wei Cheng is a child genius and mathematics who has special talent in dealing with numbers, which helps him to solve the three-body problem later.
- Homeworld Evacuation: Trisolaris is expected to be destroyed for good within a thousand years, hence their need to colonize a world outside its solar system. The fleet they're sending to invade Earth doubles as The Ark.
- Humans Advance Swiftly: One of the reasons for the Trisolarans use of the proton-sized supercomputers to spoil all particle collider research and lock humans at their current level of technology is their realisation of this. The Princeps describes their already-launched mighty conquering fleet as a funeral procession if humanity's accelerating technological advances aren't stopped.
- Inscrutable Aliens: The basis of Dark Forest theory. All civilizations in the universe destroy all other civilizations they meet because they can't establish trust. Most likely due to communication difficulty because of the extreme distance, completely different physiology, or maybe it's just not economical to deal with cultural differences and subsequent wars arising from it. The Trisolarans are unique in this regard because their homeworld is about to fall into a star and they need a new home, so they don't destroy the Earth outright.
- Insult Backfire: At the end of the book, the Trisolarans' last message to humanity is a snide "You are bugs!" In the epilogue, the human characters note that humanity has spent its entire history at war with the bugs that infest its crops, and yet those bugs are still around — implying that just because the Trisolarans are more technologically advanced, it doesn't make their victory as certain as they seem to think.
- Misanthrope Supreme: The ETO attracts quite a lot of these people, (who grow into the Adventist faction,) and it's mentioned how surprising it is just how many humans leapt at the chance to destroy their own species, including themselves and their children. Wenjie notes that this was never her intention; she honestly thought bringing a more advanced civilisation to Earth would allow humans to be saved from their own stupidity, and never foresaw that her movement to bring this about would be hijacked by humans who actually wanted their own extermination.
- Sacrificial Planet: Trisolaris used to be one of twelve planets in its system, but the other eleven fell into the suns over time due to a combination of the system's natural Gravity Screw and the suns' periodic "breathing" which caused them to de-orbit. Trisolaris itself will fall in as well inside a millennium, hence their need to find a new planet to colonize.
- Scary Dogmatic Aliens: Trisolaris society is a repeating cycle of destroyed civilizations and building up from the ashes. The result, taken from their history based on which societies were best at survival, was an authoritarian, ruthlessly utilitarian society that had no problem incinerating anybody deemed guilty of any crime or too old to be productive. Trisolarans deliberately try to cull basic animal emotion from their day to day life in favor of "calmness and numbness" since those were the best assets for societal survival in the harsh environment of Trisolaris.
- Schmuck Bait: An inverted version. The message Wenjie receives from the Trisolaran Red Coast equivalent is a sincere warning not to make any further broadcasts, lest she invite disaster on her home; however, she's sufficiently disgusted with humanity that she deliberately ignores the warning anyway.
- Science Is Good: Both zigzagged and deconstructed.
- Zigzagged: many of the characters, both heroic and villainous, are scientists, and their discoveries are merely tools that can be used for good or evil, most prominently shown with how Wang's nanofilament wire could be used both as material for a Space Elevator that the Trisolarans do NOT want built, and as a gruesome weapon that is able to slice a supertanker and its crew into ribbons.
- Deconstructed with Wenjie's assumption that this trope is absolutely true causing her to think that any civilisation that developed superior science must also have developed superior moral philosophy.
- Technology Erasure Event: The Trisolarians remotely influence technology on Earth, in particular making all particle accelerators nonfunctional, so that humans will not be capable of inventing weaponry capable of fighting against the incoming colonization fleet.
- Unusual User Interface:
- "Three Body" only supports interface via haptic (full body force-feedback) suit.
- A computer made out of 30 million people was made in the game, which the Trisolarans actually did for real, although by using their reflective skin instead of flags and hands.
- Villain Has a Point: During the Cultural Revolution, countless atrocities were committed to elevate "the common man" above such supposed elitists as academics and intellectuals. This is part of why Ye Wenjie come to despise humanity so much. However, throughout The Three-Body Problem, most of the evils we see come from one manner of "elites" or another, while the one display of human goodness that almost makes Ye Wenjie reconsider her position comes from common, uneducated people in a remote village. Also, it's explicitly noted that intellectuals are the ones who are easiest to convert to selling out their own species to the Trisolarans, while the regular working man tends to resist the notion. The implication seems to be that the Communists' failing was less in their ideals and more in not recognizing that they were, themselves, behaving in an elitist and technocratic way.
- Water Is Womanly: This trope is mentioned:"A woman should be like water, able to flow over and around anything."
- We ARE Struggling Together: Both ETO factions (Redemptionists and Adventists) spend considerable resources hunting each other. The Trisolarans engage in a bit of this as well.
- Well-Intentioned Extremist: The Redemptionists are fully aware that bringing the Trisolarans into contact with Earth is enormously dangerous for humanity, but they honestly think that contact with a greater power is humanity's best chance of being saved from its own stupidity; they explicitly use the conquest and decimation of the Mesoamericans by the Spanish as an example of something that was enormously destructive, but also caused the conquered people to discard many of their culture's most barbaric aspects.
- Woobie, Destroyer of Worlds: Played with in the case of Ye Wenjie; her life is absolutely horrific with a number of deeply personal betrayals, and yet even though her miserable life directly contributed to her world-endangering decision to invite the Trisolarans she didn't actually intend for this to be the Earth's destruction.