Trisolaran

Trisolarans are a species native to Trisolaris, the only planet in the Alpha Centauri System. They intend to invade Earth as a substitute for their endangered homeworld, and due to this their civilization as a whole acts as the main antagonist of The Three-Body Problem and its sequels.

Anatomy and Physiology
No Trisolarans are ever seen at any point in the Remembrance of Earth's Past series. Consequently, most of their physical traits, including their size and general appearance, are unknown. However, they are known to have an ability to completely dehydrate their bodies to deal with Trisolaris' chaotic and hostile climate. In this state, they can survive for centuries or more, but cannot think or act. Additionally, it is known that they communicate via patterns of visible light produced directly by their brain as it thinks. This renders speech and thought synonymous for Trisolarans, and they cannot lie to each other. Members of a previous Trisolaran civilization had reflective skin, though it is not known if their modern successors have the same trait.

Additionally, a number of other traits can be inferred. During the run-up to their arrival on Earth, they sought to preserve Earth's cities, implying that they are around the same size as humans. They also intended to inhabit Earth without modifying its atmosphere and biosphere, implying that they can use the same air and food as Earth life forms.

Diet
The diet of Trisolarans is not known. However, they are known to practice agriculture, which implies an omnivorous or herbivorous diet.

Reproduction and Life Cycle
Trisolarans have two sexes, although it is not clear if these sexes can be defined as male or female. To reproduce, two Trisolarans of opposite sex physically merge together, and then separate into three to five offspring. These offspring share some of their parent's memories and personality traits, and as such do not really go through a "childhood" stage of development. Trisolarans have a lifespan of 70-80 Earth years, not counting time spent in dehydration, although their world's harsh environment and government ensure that they do not generally live this long.

Homeworld
Trisolarans are native to the planet of Trisolaris, the only planet in the Alpha Centauri system. Trisolaris is a terrestrial planet with an erratic orbit around all three suns, resulting in a wildly unstable climate.

Orbit
Unlike the real Alpha Centauri system, the stars of the Trisolaris system are subject to the "three-body problem," meaning that their orbits around each other follow no mathematically predictable pattern and the distances between them vary wildly. Consequently, Trisolaris itself is tossed between the three stars like a football, with no consistent "days" or "years."

Atmosphere & Climate
Trisolaris' climate varies wildly depending on its location in its solar system, with no rhyme or reason. During so-called Stable Eras, the planet is in a stable orbit around one star, and it generally has a habitable Earth-like climate. During Chaotic Eras, during which it roams wildly throughout the system, its climate reaches uninhabitable extremes. Its atmosphere may freeze into snow, or its surface may turn molten. The atmosphere appears to consist mainly of nitrogen and oxygen, much like that of Earth.

Technology
Trisolarans possess technology far more advanced than that of Earth. They are capable of precisely manipulating individual subatomic particles and even of altering physical constants within set regions of space. However, they are still bound by certain physical laws, and cannot surpass the speed of light.

Sophons
Sophons are a type of sentient probe created by Trisolaris, made from single protons. To create a sophon, a proton is "unfolded" into two dimensions and engraved with circuitry that uses the strong interaction rather than electromagnetism. The resulting sophon is self-aware, capable of movement at near light speed, and able to perceive its surroundings on both the macro and micro scale. Each sophon is quantum-entangled with one other sophon, enabling instant communication between Earth and the Trisolaran Fleet. They serve primarily as nigh-omnipresent surveillance devices, and also sabotage particle accelerator experiments in order to hinder humanity's development of physics.

Droplets
Droplets are unmanned, teardrop-shaped probes, and the first Trisolaran spacecraft encountered by humanity. They are made of metal modified with an effect that extends the strong interaction to ranges similar to those of chemical bonds. The resulting substance is perfectly smooth and mirrored. Additionally, it is impossibly hard and durable, allowing a droplet to crash into targets at hundreds of kilometers per second with no harm to itself. Because of this property, droplets are often used as weapons, both against spaceships and ground targets. They are propelled by a "propulsion halo" nearly as hot as the Sun's core, which is most likely propelled by matter-antimatter annihilation.