Time viewer

Device in science fiction

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 19th century, 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. 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; Another variation involves listening to the past rather than viewing it. exotic neutrino properties in the 1956 short story "The Dead Past" by Isaac Asimov, in 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. In film, the first time viewer appeared in the 1918 film The Ghost of Slumber Mountain. 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,

In the 1938–1939 Trumpets from Oblivion series by Henry Bedford Jones, a time viewer allows scientists to discover the explanations for various myths, and 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.

The 1926 novel The Vicarion by Gardner Hunting is an early example of time viewers being used for entertainment; In the 1956 short story "The Dead Past" by Isaac Asimov, its use is suppressed by the government for this reason. In some stories, the past is changed intentionally.

Rarely, time viewers may be depicted as allowing observation of the future rather than the past. while in the 1960 The Twilight Zone episode "A Most Unusual Camera" the device only has a reach of five minutes into the future. 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.