Remembrance of Earth's Past
Remembrance of Earth's Past () is a science fiction trilogy by the Chinese writer Liu Cixin, but Chinese readers generally refer to the series by the title of its first novel, "The Three-Body Problem" (). Books. Original trilogy. The books in the "Remembrance of Earth's Past" trilogy are: Science fiction concepts. Sophons. Sophons are eleven-dimensional protons generated with Trisolaran particle accelerators. Placed into the 2nd dimension, they are embedded in circuitry to create a supercomputer, and when viewed in 3 dimensional space are typically the size of a proton though they can switch  dimensions to change sizes in 3-dimensional space. They can visually record anything and thus their secondary purpose is to act as surveillance devices, beaming the information they gather back to another sophon instantaneously via quantum entanglement. Their primary purpose for their Trisolaran manufacturers is to disrupt Earth's particle accelerators, capable of straying into the paths of fired particles and scrambling the results of experiments before re-assembling, effectively blocking advancement of the science. Since they can move through three-dimensional space at the speed of light, a single sophon is capable of disrupting all of Earth's particle  accelerators. Droplets. Trisolaran space probes are covered in a strong interaction force material. Due to this material, they are stronger than any material in the solar system and thus are impervious to any physical attack. Their propulsion system is capable of moving in any direction in 3D space. Seemingly unaffected by inertia, they can make sudden impossible turns, and their primary method of attack is to simply smash through objects. Curvature Propulsion. Simplified in a demonstration as a piece of soap attached to a paper boat on water, with the soap reducing the water tension at its end, and the  water tension disparity propelling the boat. Traveling through previous paths slows the boat down due to decreased surface tension. Curvature Propulsion is a method of light speed travel that utilizes the same concept, via reducing the speed of light it is possible to drag a ship through space at light speed, while its wake is a reduced light-speed region of space. Hibernation. Humanity by the time of the Dark Forest has developed cryogenic technology, capable of preserving a human life, unaging, for hundreds of years barring certain genetic disorders. Initially, it is viewed as a sign of inequality before  it is fully developed, viewed as a way for the rich to simply skip through the centuries to eras of more advanced technology, peace, and human development. With the advent of the Trisolaran invasion, however, it becomes a near-worthless technology in terms of demand, as people prefer to die naturally in a world still free from Trisolaris rather than skip ahead to doomsday. Because of this, only researchers and certain high-value staff make use of cryogenics to skip through time. Cosmic sociology. The study of theoretical interactions between cosmic civilizations. This area of study is first proposed by  the character Ye Wenjie in conversation with future Wallfacer Luo Ji. Ye Wenjie proposes two axioms of cosmic sociology: "First: Survival is the primary need of civilization. Second: Civilization continuously grows and expands, but the total matter in the universe remains constant." After becoming a Wallfacer, Luo Ji uses the axioms provided by Ye Wenjie to invent the dark forest theory of the universe and the idea of dark forest deterrence to stop the Trisolaran invasion. Adaptations. "The Three-Body Problem" () is a postponed Chinese science fiction 3D film in-progress, adapted from "The Three-Body Problem", directed by Fanfan  Zhang, and starring Feng Shaofeng and Zhang Jingchu. A series based on the trilogy has been ordered by Netflix, with David Benioff, D. B. Weiss, and Alexander Woo set to write and executive produce. Influences. The series is described in the New Yorker as having Hobbesian underpinnings and as a metaphor for China-United States relations. Liu himself, however, has resisted such comparisons, declaring: "The whole point is to escape the real world!"