In science fiction, a time viewer, temporal viewer, or chronoscope is a device that allows another point in time to be observed.The concept has appeared since the late 1800s, constituting a significant yet relatively obscure subgenre of time travel fiction and appearing in various media including literature, cinema, and television. Stories usually explain the technology by referencing cutting-edge science, though sometimes invoking the supernatural instead. Most commonly only the past can be observed, though occasionally time viewers capable of showing the future appear; these devices are sometimes limited in terms of what information about the future can be obtained. Other variations on the concept include being able to listen to the past but not view it.
One reason authors may choose to write about time viewers rather than time machines is to circumvent the issue of temporal paradoxes. Recurring applications include studying history, solving crimes, and entertainment in the form of displaying historic events to an audience. Because the past includes events as recently as the previous second, privacy may be compromised by such devices; several stories explore the implications thereof. Other stories examine the effects of being observed by onlookers further into the future. An unanticipated influence on past events is a common motif in stories about time viewers, and exploiting this side-effect appears in some stories.
In its most basic form, a time viewer is a device that only allows the observation of the past. : 97 Unlike with a time machine, the user is not transported from one moment in time to another. Under the strictest definition it cannot alter the past; : 97 however, the unexpected discovery that the device does indeed affect the past is a common motif. : 99 Variations on the concept where the future rather than the past is observed are more uncommon but nevertheless appear in multiple works. : 128 Another variation involves listening to the past rather than viewing it. : 97–98
In-universe justifications for the ability to observe the past vary, typically corresponding to contemporary scientific developments; : 98 time viewers exploit impressions on the aether in the 1926 novel The Vicarion by Gardner Hunting, : 58 exotic neutrino properties in the 1956 short story "The Dead Past" by Isaac Asimov, : 104–105 and wormholes in the 2000 novel The Light of Other Days by Stephen Baxter and Arthur C. Clarke. : 158–159 A common explanation involves the finite speed of light and astronomical distances; this method appears in the 1935 short story "The Space Lens" by Donald A. Wollheim, among others. A variation that appears in the 1966 short story "Light of Other Days" by Bob Shaw (later included in the 1972 fix-up novel Other Days, Other Eyes ) is using slow glass whose high refractive index means light takes years to pass through it. : 105 : 127–128 Supernatural explanations also occur in works like the 1925 short story "A View From a Hill" by M. R. James, where a pair of binoculars are enchanted to show the past, and the 1976 short story "Balsamo's Mirror" by L. Sprague de Camp, where the titular mirror allows a present-day person to view the world through the eyes of one from the past. : 100
The earliest known example of a fully fledged time viewer in fiction appears in the 1883 short story "L'historioscope" by Eugène Mouton in the form of an electrical telescope, though it was prefigured by a couple of proto-variations on the concept; : 251 In film, the first time viewer appeared in the 1918 film The Ghost of Slumber Mountain . The concept has appeared regularly in works of fiction ever since, creating a sub-genre within time travel fiction, but remained comparatively obscure. : 97 : 57–58 : 71 : 532–533in the 1872 work Recits de l'infini (which later turned into the 1887 novel Lumen ) by Camille Flammarion a spirit accomplishes the same effect by travelling faster than light, and the titular device in the 1873 short story "The Automaton Ear" by Florence McLandburgh enables listening to the past.
Science fiction author Stephen Baxter identifies several different ways time viewers are used in fiction. The most basic premise is of the time viewer as simply a "neat gadget", with a common variation being something going wrong, typically the past being unintentionally altered. Changing the past on purpose is another recurring application. According to Baxter, the wider implications of the existence of time viewers are sometimes explored in hard science fiction by performing what's known as a PEST (Political, Economic, Social, and Technical) analysis. : 98–99, 101
Several authors consider time viewers to be inherently more plausible than time machines. Science fiction author Damien Broderick says that "using a time viewer is in essence no more absurd than watching a movie made 50 years ago" since the past cannot be affected by it. : 71 Baxter similarly says that time viewers are more extrapolation than fantasy, comparing them to archaeological research. : 97 For this reason, science writer Paul J. Nahin and physicist Stephen Webb say that a benefit for writers is being able to write time travel stories without needing to consider the possibility of time paradoxes; : 128 : 57–58 Nahin nevertheless notes that interacting with the past via a time machine, or even affecting it, does not necessarily cause paradoxes. : 57
Time viewers are sometimes used to observe moments in history that are similarly popular destinations for time travel in fiction, one example being the crucifixion of Jesus in the 1904 novel Around a Distant Star by Jean Delaire. : 534 In the 1956 short story "The Dead Past" by Isaac Asimov, a historian is excited to use a time viewer to study ancient Carthage, only to find out that the device is limited to viewing the most recent 120 years, : 127 and a historian uses a time viewer to read the contents of the Library of Alexandria in the 1980 short story "One Time in Alexandria" by Donald Franson. : 283
In the 1938–1939 Trumpets from Oblivion series by Henry Bedford-Jones, a time viewer allows scientists to discover the explanations for various myths, : 103 : 127 Revealing the truth about historical events also appears in the 1953 novel Childhood's End by Arthur C. Clarke, where alien invaders show humanity that our religions are false. : 102–103and two war veterans use a time viewer to create historical films in order to dispel public misconceptions about the American Revolution and the American Civil War in the 1947 novelette "E for Effort" by T. L. Sherred.
Astronomy is similarly studied in the 1969 novel Macroscope by Piers Anthony and the 1999 short story "Hatching the Phoenix" by Frederik Pohl. In the former the formation of the Solar System is studied, while in the latter observations are made of a world that has since been destroyed by a supernova. : 160Scientists in the 2000 novel The Light of Other Days by Stephen Baxter and Arthur C. Clarke use time viewer technology to study the entire history of life on Earth.
An early instance of a time viewer being used to solve crimes is the 1926 novel The Vicarion by Gardner Hunting, as events leading up to a crime can be uncovered in reverse after the fact. : 101–102 Later examples include the 1948 short story "Private Eye" by Henry Kuttner and C. L. Moore (writing jointly as "Lewis Padgett"), which revolves around a man planning a murder in such a way that the use of a time viewer by the authorities would not reveal his guilt, : 103–104 and the 2006 film Déjà Vu , where the device shows events with a four-day delay which cannot be adjusted and there is consequently only one opportunity to view any given event.
The 1926 novel The Vicarion by Gardner Hunting is an early example of time viewers being used for entertainment; : 101–102 This theme recurs in the 1947 novelette "E for Effort" by T. L. Sherred, though in that story the public is unaware that the films are not conventional movie productions. : 127in the story, moments from history are shown in movie theaters to great public interest. Baxter compares the in-story effects on society, where "mass addiction to this vibrant spectacle quickly overtakes the public", to the later real-world advent of the television.
A number of works explore the implications of being capable of remotely viewing the recent past—potentially as recent as less than a second ago—on privacy. : 101–102, 104–105 : 127–128 : 266 In the 1956 short story "The Dead Past" by Isaac Asimov, its use is suppressed by the government for this reason. : 104–105 : 127 In the 1972 fix-up novel Other Days, Other Eyes by Bob Shaw, particles of the slow glass that captures images are spread all over to enable mass surveillance. The 1976 short story "I See You" by Damon Knight posits that the complete loss of privacy resulting from universal access to a time viewer would usher in a utopia free from deceit and embarrassment. : 104
Espionage applications appeared early; in the 1926 short story "The Time Eliminator" by pseudonymous author "Kaw", the United States government uses a time viewer to spy on a meeting of foreign leaders. : 101 The realization that it can be put to this use triggers war to ensure that it does not in the 1947 novelette "E for Effort" by T. L. Sherred. : 103
The implication that just as we are watching the past, people in the future are surely watching us is explored in the 1951 short story "Operation Peep" by John Wyndham. In order to regain privacy, people eventually resort to shining bright lights to effectively blind the future onlookers. : 102 In the 1953 short story "The Parasite" by Arthur C. Clarke, the realization that he is constantly being watched by a future being eventually drives a man to suicide. : 102 The intensity of observation from the future is measured in the 1981 short story "The Final Days" by David Langford to gauge an individual's importance to the world of the future.
Several stories reveal that the time viewer can not only observe the past but influence it. : 99 In the 1951 short story "The Biography Project" by H. L. Gold, being constantly watched drives Isaac Newton insane. : 99 In the satirical 1948 short story "The Brooklyn Project" by William Tenn, the scientists in charge insist that the past is immutable even as they and their surroundings undergo drastic changes, because from their new perspective those alterations have always been in place. : 99 : 205
In some stories, the past is changed intentionally. : 99 Humorous depictions include the 1972 short story "The Greatest Television Show on Earth" by J. G. Ballard, where a TV company hires additional people as soldiers to make the Battle of Waterloo live up to viewers' expectations, and the 1967 novel The Technicolor Time Machine by Harry Harrison, which implies that the Viking settlement of Vinland only happened because Hollywood wanted to make a movie about it. : 99 A more serious treatment appears in the 1996 novel Pastwatch: The Redemption of Christopher Columbus by Orson Scott Card: : 99 after discovering that the past has previously been tampered with, a team of future scientists seek to undo the harm caused by Christopher Columbus's voyages to the New World, even though it would mean their timeline would be obliterated. : 187–188 : 258–261 : 54
Rarely, time viewers may be depicted as allowing observation of the future rather than the past. : 128 Stephen Webb argues that viewing the future has more in common with fantasy and fortune-telling than with science fiction, : 128 and David Langford notes in The Encyclopedia of Science Fiction that the possibility of viewing the future has implications for the question of free will versus determinism.
Devices capable of viewing the future have been portrayed in various ways. In the 1922 short story "The Prophetic Camera" by Lance Sieveking, the titular camera can take pictures an adjustable amount of time into the future, : 685 while in the 1960 The Twilight Zone episode "A Most Unusual Camera" the device only has a reach of five minutes into the future. : 60 In the 1955 novel The Pleasures of a Futuroscope by Lord Dunsany, the device reveals a future nuclear holocaust. In the 1924 short film The Fugitive Futurist a gambler is offered to buy a future-viewing device which he intends to use to find out which horses to bet on, though the device turns out to be fake. The chronoscope in the 1936 short story "Elimination" by John W. Campbell can show both the past and all possible futures. : 60
Future-viewing devices are occasionally limited in what they are able to show rather than being general-purpose. : 128 Another is the instantaneous "Dirac communicator" introduced in the 1954 short story "Beep" by James Blish which due to the lack of a speed-of-light delay can send messages to the past. : 148–150One example is the device in the 1939 short story "Life-Line" by Robert A. Heinlein which can determine an individual's moment of death by measuring the reflection from the future end of that person's world line; a similar device that reveals the manner but not time of death appears in the 2010 anthology Machine of Death: A Collection of Stories About People Who Know How They Will Die by Ryan North, Matthew Bennardo, and David Malki.
An ansible is a category of fictional devices or technology capable of near-instantaneous or faster-than-light communication. It can send and receive messages to and from a corresponding device over any distance or obstacle whatsoever with no delay, even between star systems. As a name for such a device, the word "ansible" first appeared in a 1966 novel by Ursula K. Le Guin. Since that time, the term has been broadly used in the works of numerous science fiction authors, across a variety of settings and continuities. A related term is ultrawave.
Mars, the fourth planet from the Sun, has appeared as a setting in works of fiction since at least the mid-1600s. Trends in the planet's portrayal have largely been influenced by advances in planetary science. It became the most popular celestial object in fiction in the late 1800s, when it became clear that there was no life on the Moon. The predominant genre depicting Mars at the time was utopian fiction. Around the same time, the mistaken belief that there are canals on Mars emerged and made its way into fiction, popularized by Percival Lowell's speculations of an ancient civilization having constructed them. The War of the Worlds, H. G. Wells's novel about an alien invasion of Earth by sinister Martians, was published in 1897 and went on to have a major influence on the science fiction genre.
The Encyclopedia of Science Fiction (SFE) is an English language reference work on science fiction, first published in 1979. It has won the Hugo, Locus and British SF Awards. Two print editions appeared in 1979 and 1993. A third, continuously revised, edition was published online from 2011; a change of web host was announced as the launch of a fourth edition in 2021.
The Moon has appeared in fiction as a setting since at least classical antiquity. Throughout most of literary history, a significant portion of works depicting lunar voyages has been satirical in nature. From the late 1800s onwards, science fiction has successively focused largely on the themes of life on the Moon, first Moon landings, and lunar colonization.
Time travel is a common theme in fiction, mainly since the late 19th century, and has been depicted in a variety of media, such as literature, television, film, and advertisements.
Fictional depictions of Mercury, the innermost planet of the Solar System, have gone through three distinct phases. Before much was known about the planet, it received scant attention. Later, when it was incorrectly believed that it was tidally locked with the Sun creating a permanent dayside and nightside, stories mainly focused on the conditions of the two sides and the narrow region of permanent twilight between. Since that misconception was dispelled in 1965, the planet has again received less attention from fiction writers, and stories have largely concentrated on the harsh environmental conditions that come from the planet's proximity to the Sun.
Jupiter, the largest planet in the Solar System, has appeared in works of fiction across several centuries. The way the planet has been depicted has evolved as more has become known about its composition; it was initially portrayed as being entirely solid, later as having a high-pressure atmosphere with a solid surface underneath, and finally as being entirely gaseous. It was a popular setting during the pulp era of science fiction. Life on the planet has variously been depicted as identical to humans, larger versions of humans, and non-human. Non-human life on Jupiter has been portrayed as primitive in some works and more advanced than humans in others.
Saturn has made appearances in fiction since the 1752 novel Micromégas by Voltaire. In the earliest depictions, it was portrayed as having a solid surface rather than its actual gaseous composition. In many of these works, the planet is inhabited by aliens that are usually portrayed as being more advanced than humans. In modern science fiction, the Saturnian atmosphere sometimes hosts floating settlements. The planet is occasionally visited by humans and its rings are sometimes mined for resources.
Pluto has appeared in fiction as a setting since shortly after its 1930 discovery, albeit infrequently. It was initially comparatively popular as it was newly discovered and thought to be the outermost object of the Solar System and made more fictional appearances than either Uranus or Neptune, though still far fewer than other planets. Alien life, sometimes intelligent life and occasionally an entire ecosphere, is a common motif in fictional depictions of Pluto. Human settlement appears only sporadically, but it is often either the starting or finishing point for a tour of the Solar System. It has variously been depicted as an originally extrasolar planet, the remnants of a destroyed planet, or entirely artificial. Its moon Charon has also appeared in a handful of works.
Asteroids have appeared in fiction since the 1800s, the first one—Ceres—having been discovered in 1801. A theory to explain the existence of the asteroid belt that was popular in the 1800s was that it consists of the remnants of a planet predicted by the Titius–Bode law to exist between Mars and Jupiter that had somehow been destroyed, and this was reflected in early science fiction works such as Robert Cromie's 1895 novel The Crack of Doom; several works of the 1950s reused this idea to warn of the dangers of nuclear weapons. Early works also tended to depict the asteroid belt as a region that must be navigated carefully lest one's spaceship should collide with one of the asteroids, one example being Isaac Asimov's 1939 short story "Marooned off Vesta"; later works mostly recognize that the individual asteroids are very far apart and accordingly pose little danger to spacecraft, the Star Wars films being an exception to this general rule. A concept of more enduring popularity is that of asteroid mining, featured in early works such as Clifford D. Simak's 1932 short story "The Asteroid of Gold"—where asteroids were often the setting of a space version of the Klondike Gold Rush—as well as more modern works like Ben Bova's 2001 novel The Precipice. Another use humans have found for asteroids in fiction is turning them into space stations or habitats, often by hollowing them out, as in Robert A. Heinlein's 1939 short story "Misfit". Impact events or threats thereof are depicted in numerous works such as Arthur C. Clarke's 1993 novel The Hammer of God, and in the 1985 novel Footfall by Larry Niven and Jerry Pournelle they are outright weaponized.
The Loch Ness Monster is a creature from folklore that has appeared in popular culture in various genres since at least 1934. It is most often depicted as a relict dinosaur or similar, but other explanations for its existence such as being a shapeshifter or from outer space also appear. It is only occasionally portrayed as threatening, despite its name.
Neptune has appeared in fiction since shortly after its 1846 discovery, albeit infrequently. It initially made appearances indirectly—e.g. through its inhabitants—rather than as a setting. The earliest stories set on Neptune itself portrayed it as a rocky planet rather than as having its actual gaseous composition; later works rectified this error. Extraterrestrial life on Neptune is uncommon in fiction, though the exceptions have ranged from humanoids to gaseous lifeforms. Neptune's largest moon Triton has also appeared in fiction, especially in the late 20th century onwards.
Uranus has been used as a setting in works of fiction since shortly after its 1781 discovery, albeit infrequently. The earliest depictions portrayed it as having a solid surface, whereas later stories portrayed it more accurately as a gaseous planet. Its moons have also appeared in a handful of works. Both the planet and its moons have experienced a slight trend of increased representation in fiction over time.
Pantropy is a hypothetical process of space habitation or space colonization in which, rather than terraforming other planets or building space habitats suitable for human habitation, humans are modified to be able to thrive in the existing environment. The term was coined by science fiction author James Blish, who wrote a series of short stories based on the idea.
Black holes, objects whose gravity is so strong that nothing including light can escape them, have been depicted in fiction since before the term was coined by John Archibald Wheeler in the late 1960s. Black holes have been depicted with varying degrees of accuracy to the scientific understanding of them. Because what lies beyond the event horizon is unknown and by definition unobservable from outside, authors have been free to employ artistic license when depicting the interiors of black holes.
Immortality is a common theme in fiction. The concept has been depicted since the Epic of Gilgamesh, the oldest known work of fiction. Originally appearing in the domain of mythology, it has later become a recurring element in the genres of horror, science fiction, and fantasy. For most of literary history, the dominant perspective has been that the desire for immortality is misguided, albeit strong; among the posited drawbacks are ennui, loneliness, and social stagnation. This view was challenged in the 20th century by writers such as George Bernard Shaw and Roger Zelazny. Immortality is commonly obtained either from supernatural entities or objects such as the Fountain of Youth or through biological or technological means such as brain transplants.
Supernovae have been featured in works of fiction. While a nova is strictly speaking a different type of astronomical event, science fiction writers often use the terms interchangeably and refer to stars "going nova" without further clarification; this can at least partially be explained by the earliest science fiction works featuring these phenomena predating the introduction of the term "supernova" as a separate class of event in 1934. Since these stellar explosions release enormous amounts of energy, some stories propose using them as a power source for extremely energy-intense processes, such as time travel in the Doctor Who serial The Three Doctors from 1972. For the same reason, inducing them is occasionally portrayed as a potential weapon, for instance in the 1966 novel The Solarians by Norman Spinrad.
Comets have appeared in numerous works of fiction. One of the earliest such works is Edgar Allan Poe's 1839 short story "The Conversation of Eiros and Charmion", wherein the Earth's atmosphere is lost to a comet, with catastrophic results. Destruction is also caused by impact events in works such as the 1977 novel Lucifer's Hammer by Larry Niven and Jerry Pournelle, and the impact of Comet Shoemaker–Levy 9 on Jupiter in 1994 was satirized by Terry Pratchett in his 1998 Discworld novel The Last Continent. Looming threats posed by comets are depicted in many works including Dennis Wheatley's 1939 novel Sixty Days to Live and the 1998 film Deep Impact. Conversely, H. G. Wells' 1906 novel In the Days of the Comet provides a rare example of positive effects arising from Earth encountering a comet, the gases in the comet's tail altering the atmosphere in a way that transforms human character for the better.
Jane Palmer is an author and illustrator of speculative fiction from the United Kingdom. In addition to novels, she writes short stories and children's picture books.
The Sun has appeared as a setting in fiction since at least classical antiquity, but for a long time it received relatively sporadic attention. Many of the early depictions viewed it as an essentially Earth-like and thus potentially habitable body—a once-common belief about celestial objects in general known as the plurality of worlds—and depicted various kinds of solar inhabitants. As more became known about the Sun through advances in astronomy, in particular its temperature, solar inhabitants fell out of favour save for the occasional more exotic alien lifeforms. Instead, many stories focused on the eventual death of the Sun and the havoc it would wreak upon life on Earth. Before it was understood that the Sun is powered by nuclear fusion, the prevailing assumption among writers was that combustion was the source of its heat and light, and it was expected to run out of fuel relatively soon. Even after the true source of the Sun's energy was discovered in the 1920s, the dimming or extinction of the Sun remained a recurring theme in disaster stories, with occasional attempts at averting disaster by reigniting the Sun. Another common way for the Sun to cause destruction is by exploding, and other mechanisms such as solar flares also appear on occasion.
"The Brooklyn Project" however is one of my favorite time travel stories. Despite warnings that changes wrought in the past would be undetectable because people in the present would assume they had always been the case, an experiment leads to the replacement of humanity by intelligent amoebas.