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Charon (moon)

Charon ( or  ), or (134340) Pluto I, is the largest of the five known natural satellites of the dwarf planet Pluto. It has a mean radius of 606 km. Charon is the sixth-largest known trans-Neptunian object after Pluto, Eris, Haumea, Makemake, and Gonggong. It was discovered in 1978 at the United States Naval Observatory in Washington, D.C., using photographic plates taken at the United States Naval Observatory Flagstaff Station (NOFS).

With half the diameter and one-eighth the mass of Pluto, Charon is a very large moon in comparison to its parent body. Its gravitational influence is such that the barycenter of the Plutonian system lies outside Pluto, and the two bodies are tidally locked to each other. The dwarf planet systems Pluto–Charon and Eris–Dysnomia are the only known examples of mutual tidal locking in the Solar System, though it is likely that –Vanth is another.

The reddish-brown cap of the north pole of Charon is composed of tholins, organic macromolecules that may be essential ingredients of life. These tholins were produced from methane, nitrogen, and related gases which may have been released by cryovolcanic eruptions on the moon, or may have been transferred over 19,000 km from the atmosphere of Pluto to the orbiting moon.

The New Horizons spacecraft is the only probe that has visited the Pluto system. It approached Charon to within 27000 km in 2015.

Discovery

Charon was discovered by United States Naval Observatory astronomer James Christy, using the 61 in telescope at United States Naval Observatory Flagstaff Station (NOFS). On June 22, 1978, he had been examining highly magnified images of Pluto on photographic plates taken with the telescope two months prior. Christy noticed that a slight elongation appeared periodically. The bulge was confirmed on plates dating back to April 29, 1965. Subsequent observations of Pluto determined that the bulge was due to a smaller accompanying body. The periodicity of the bulge corresponded to Pluto's rotation period, which was previously known from Pluto's light curve. This indicated a synchronous orbit, which strongly suggested that the bulge effect was real and not spurious. This resulted in reassessments of Pluto's size, mass, and other physical characteristics because the calculated mass and albedo of the Pluto–Charon system had previously been attributed to Pluto alone. The International Astronomical Union formally announced Christy's discovery to the world on July 7, 1978.

Doubts about Charon's existence were erased when it and Pluto entered a five-year period of mutual eclipses and transits between 1985 and 1990. This occurs when the Pluto–Charon orbital plane is edge-on as seen from Earth, which only happens at two intervals in Pluto's 248-year orbital period. It was fortuitous that one of these intervals happened to occur soon after Charon's discovery.

Name
Charon was first given the temporary designation S/1978 P 1, after its discovery, following the then recently instituted convention. On June 24, 1978, Christy first suggested the name Charon as a scientific-sounding version of his wife Charlene's nickname, "Char". Although colleagues at the Naval Observatory proposed Persephone, Christy stuck with Charon after discovering that it was serendipitously the name of an appropriate mythological figure: Charon (Χάρων) is the ferryman of the dead, closely associated with the god Pluto. The IAU officially adopted the name in late 1985, and it was announced on January 3, 1986.

Coincidentally, nearly four decades before Charon's discovery, science fiction author Edmond Hamilton had invented three moons of Pluto for his 1940 novel Calling Captain Future and named them Charon, Styx, and Cerberus; Styx and Kerberos are the two smallest Plutonian moons, and were named in 2013.

There is minor debate over the preferred pronunciation of the name. The mythological figure is pronounced with a sound, and this is often followed for the moon as well. However, Christy himself pronounced the initial $2,452,600.5$ as a sound, as he had named the moon after his wife Charlene. Many English-speaking astronomers follow the classical convention, but others follow Christy's,  and that is the prescribed pronunciation at NASA and of the New Horizons team.

Orbit
Charon and Pluto orbit each other every 6.387 days. The two objects are gravitationally locked to one another, so each keeps the same face towards the other. This is a case of mutual tidal locking, as compared to that of the Earth and the Moon, where the Moon always shows the same face to Earth, but not vice versa. The average distance between Charon and Pluto is 19570 km. The discovery of Charon allowed astronomers to calculate accurately the mass of the Plutonian system, and mutual occultations revealed their sizes. However, neither indicated the two bodies' individual masses. Those could only be estimated, until the discovery of Pluto's outer moons in late 2005. Details in the orbits of the outer moons then revealed that Charon has approximately 12% of the mass of Pluto.

Formation
Simulation work published in 2005 by Robin Canup suggested that Charon could have been formed by a collision around 4.5 billion years ago, much like Earth and the Moon. In this model, a large Kuiper belt object struck Pluto at high velocity, destroying itself and blasting off much of Pluto's outer mantle, and Charon coalesced from the debris. However, such an impact should result in an icier Charon and rockier Pluto than scientists have found. It is now thought that Pluto and Charon might have been two bodies that collided before going into orbit around each other. The collision would have been violent enough to boil off volatile ices like methane but not violent enough to have destroyed either body. The very similar density of Pluto and Charon implies that the parent bodies were not fully differentiated when the impact occurred.

Physical characteristics
Charon's diameter is 1212 km, just over half that of Pluto. Larger than the dwarf planet Ceres, it is the twelfth-largest natural satellite in the Solar System. Charon is even similar in size to Uranus's moons Umbriel and Ariel. Charon's slow rotation means that there should be little flattening or tidal distortion if Charon is sufficiently massive to be in hydrostatic equilibrium. Any deviation from a perfect sphere is too small to have been detected by observations by the New Horizons mission. This is in contrast to Iapetus, a Saturnian moon similar in size to Charon but with a pronounced oblateness dating to early in its history. The lack of such oblateness in Charon could mean that it is currently in hydrostatic equilibrium, or simply that its orbit approached its current one early in its history, when it was still warm.

Based on mass updates from observations made by New Horizons the mass ratio of Charon to Pluto is 0.1218:1. This is much larger than the Moon to the Earth: 0.0123:1. Because of the high mass ratio, the barycenter is outside of the radius of Pluto, and the Pluto–Charon system has been referred to as a dwarf double planet. With four smaller satellites in orbit about the two larger worlds, the Pluto–Charon system has been considered in studies of the orbital stability of circumbinary planets.

Internal structure
Charon's volume and mass allow calculation of its density, $19,595.764$, from which it can be determined that Charon is slightly less dense than Pluto and suggesting a composition of 55% rock to 45% ice (± 5%), whereas Pluto is about 70% rock. The difference is considerably lower than that of most suspected collisional satellites.

Following the New Horizons flyby, numerous discovered features on Charon's surface strongly indicated that Charon is differentiated, and may even have had a subsurface ocean early in its history. The past resurfacing observed on Charon's surface indicated that Charon's ancient subsurface ocean may have fed large-scale cryoeruptions on the surface, erasing many older features. As a result, two broad competing views on the nature of Charon's interior arose: the so-called hot start model, where Charon's formation is rapid and involves a violent impact with Pluto, and the cold start model, where Charon's formation is more gradual and involves a less violent impact with Pluto.

According to the hot start model, Charon accreted rapidly (within ~$17,181$ years) from the circumplanetary disc, resulting from a highly-disruptive giant impact scenario. This rapid time scale prevents the heat from accretion from radiating away during the formation process, leading to the partial melting of Charon's outer layers. However, Charon's crust failed to reach a melt fraction where complete differentiation occurs, leading to the crust retaining part of its silicate content upon freezing. A liquid subsurface ocean forms during or soon after Charon's accretion and persists for approximately 2 billion years before freezing, possibly driving cryovolcanic resurfacing of Vulcan Planitia. Radiogenic heat from Charon's core could then melt a second subsurface ocean composed of a eutectic water-ammonia mixture before it too freezes, possibly driving the formation of Kubrick Mons and other similar features. These freezing cycles could increase Charon's size by >20 km, leading to the formation of the complex tectonic features observed in Serenity Chasma and Oz Terra.

In contrast, the cold start model argues that a large subsurface ocean early in Charon's history is not necessary to explain Charon's surface features, and instead proposes that Charon may have been homogeneous and more porous at formation. According to the cold start model, as Charon's interior begins to warm due to radiogenic heating and heating from serpentinization, a phase of contraction begins, largely driven by compaction in Charon's interior. Approximately 100-200 million years after formation, enough heat builds up to where a subsurface ocean melts, leading to rapid differentiation, further contraction, and the hydration of core rocks. Despite this melting, a pristine crust of amorphous water ice on Charon remains. After this period, differentiation continues, but the core can no longer absorb more water, and thus freezing at the base of Charon's mantle begins. This freezing drives a period of expansion until Charon's core becomes warm enough to begin compaction, starting a final period of contraction. Serenity Chasma may have formed from the expansion episode, whilst the final contraction episode may have given rise to the arcuate ridges observed in Mordor Macula.

Surface
Unlike Pluto's surface, which is composed of nitrogen and methane ices, Charon's surface appears to be dominated by the less volatile water ice.

In 2007, observations by the Gemini Observatory detected patches of ammonia hydrates and water crystals on the surface of Charon that suggested the presence of active cryogeysers and cryovolcanoes. The fact that the ice was still in crystalline form suggested it may have been deposited recently, as it was expected that solar radiation would have degraded it to an amorphous state after roughly thirty thousand years. However, following new data from the New Horizons flyby, no active cryovolcanoes or geysers were detected. Later research has also called into question the cryovolcanic origin for the crystalline water ice and ammonia features, with some researchers instead proposing that ammonia may be replenished passively from underground material.

Photometric mapping of Charon's surface shows a latitudinal trend in albedo, with a bright equatorial band and darker poles. The north polar region is dominated by a very large dark area informally dubbed "Mordor" by the New Horizons team. The favored explanation for this feature is that it is formed by condensation of gases that escaped from Pluto's atmosphere. In winter, the temperature is −258 °C, and these gases, which include nitrogen, carbon monoxide, and methane, condense into their solid forms; when these ices are subjected to solar radiation, they chemically react to form various reddish tholins. Later, when the area is again heated by the Sun as Charon's seasons change, the temperature at the pole rises to −213 °C, resulting in the volatiles sublimating and escaping Charon, leaving only the tholins behind. Over millions of years, the residual tholin builds up thick layers, obscuring the icy crust. In addition to Mordor, New Horizons found evidence of extensive past geology that suggests that Charon is probably differentiated; in particular, the southern hemisphere has fewer craters than the northern and is considerably less rugged, suggesting that a massive resurfacing event—perhaps prompted by the partial or complete freezing of an internal ocean—occurred at some point in the past and removed many of the earlier craters.

Charon has a system of extensive grabens and scarps, such as Serenity Chasma, which extend as an equatorial belt for at least 1000 km. Argo Chasma potentially reaches as deep as 9 km, with cliffs that may rival Verona Rupes on Miranda for the title of the tallest cliff in the Solar System.

Hypothesized exosphere
In contrast to Pluto, Charon has no significant atmosphere. There has been speculation about an extremely exosphere surrounding the moon contributing to the formation of dark regions such as Mordor Macula. The strong seasons experienced by Pluto and Charon could provide brief periods of exosphere formation as methane sublimates on Charon, interspersed by centuries of dormancy.

Pluto does have a thin but significant atmosphere, and under some conditions Charon's gravitation may pull some of Pluto's upper atmosphere, specifically nitrogen, from Pluto's ice formations, toward Charon's surface. The nitrogen is mostly caught in the combined center of gravity between the two bodies before reaching Charon, but any gas that does reach Charon is held closely against the surface. The gas is mostly made up of ions of nitrogen, but the amounts are negligible compared to the total of Pluto's atmosphere.

The many spectral signatures of ice formations on the surface of Charon have led some to believe that the ice formations could supply an atmosphere, but atmosphere supplying formations have not been confirmed yet. Many scientists theorize that these ice formations could be concealed out of direct sight, either in deep craters or beneath Charon's surface. Similar to how Pluto transfers atmosphere to Charon, Charon's relatively low gravity, due to its low mass, causes any atmosphere that might be present to rapidly escape the surface into space. Even through stellar occultation, which is used to probe the atmosphere of stellar bodies, scientists cannot confirm an existing atmosphere; this was tested in 1986 while attempting to perform stellar occultation testing on Pluto. Charon also acts as a protector for Pluto's atmosphere, blocking the solar wind that would normally collide with Pluto and damage its atmosphere. Since Charon blocks these solar winds, its own atmosphere is diminished, instead of Pluto's. This effect is also a serious potential explanation for Charon's lack of atmosphere; when it begins to accumulate, the solar winds shut it down. Although, it is still possible for Charon to have an atmosphere. As previously stated, Pluto transfers some of its atmospheric gas to Charon, from where it tends to escape into space. Assuming Charon's density is 1.71 g/cm3, which is the rough estimate we currently have, it would have a surface gravity of 0.6 of Pluto's. It also has a higher mean molecular weight than Pluto and a lower exobase surface temperature, so that the gases in its atmosphere would not escape as rapidly from Charon as they do from Pluto.

There has been significant proof of CO2 gas and H2O vapor on the surface of Charon, but these vapors are not sufficient for a viable atmosphere due to their low vapor pressures. Pluto's surface has abundant ice formations, but these are volatile, as they are made up of volatile substances like methane. These volatile ice structures cause a good deal of geological activity, keeping its atmosphere constant, while Charon's ice structures are mainly made up of water and carbon dioxide, much less volatile substances that can stay dormant and not affect the atmosphere much.

Observation and exploration
Since the first blurred images of the moon (1), images showing Pluto and Charon resolved into separate disks were taken for the first time by the Hubble Space Telescope in the 1990s (2). The telescope was responsible for the best, yet low-quality images of the moon. In 1994, the clearest picture of the Pluto–Charon system showed two distinct and well-defined disks (3). The image was taken by Hubble's Faint Object Camera (FOC) when the system was 4.4 billion kilometers (2.6 billion miles) away from Earth Later, the development of adaptive optics made it possible to resolve Pluto and Charon into separate disks using ground-based telescopes. Although ground-based observation is very challenging, a group of amateur astronomers in Italy used a 14-inch telescope in 2008 to successfully resolve Charon in an image of Pluto.

In June 2015, the New Horizons spacecraft captured consecutive images of the Pluto–Charon system as it approached it. The images were put together in an animation. It was the best image of Charon to that date (4). In July 2015, the New Horizons spacecraft made its closest approach to the Pluto system. It is the only spacecraft to date to have visited and studied Charon. Charon's discoverer James Christy and the children of Clyde Tombaugh were guests at the Johns Hopkins Applied Physics Laboratory during the New Horizons closest approach.

Classification
The center of mass (barycenter) of the Pluto–Charon system lies outside either body. Because neither object truly orbits the other, and Charon has 12.2% of the mass of Pluto, it has been argued that Charon should be considered to be part of a binary planet with Pluto. The International Astronomical Union (IAU) states that Charon is a satellite of Pluto, but the idea that Charon might be classified as a dwarf planet in its own right may be considered at a later date.

In a draft proposal for the 2006 redefinition of the term, the IAU proposed that a planet is defined as a body that orbits the Sun that is large enough for gravitational forces to render the object (nearly) spherical. Under this proposal, Charon would have been classified as a planet, because the draft explicitly defined a planetary satellite as one in which the barycenter lies within the major body. In the final definition, Pluto was reclassified as a dwarf planet, but a formal definition of a planetary satellite was not decided upon. Charon is not in the list of dwarf planets currently recognized by the IAU. Had the draft proposal been accepted, even the Moon would hypothetically be classified as a planet in billions of years when the tidal acceleration that is gradually moving the Moon away from Earth takes it far enough away that the center of mass of the system no longer lies within Earth.

The other moons of Pluto – Nix, Hydra, Kerberos, and Styx –  orbit the same barycenter but they are not large enough to be spherical and they are simply considered to be satellites of Pluto (or of Pluto–Charon).

title: Charon (moon)


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Kirkwood gap

Kirkwood Gaps.svg showing the four most prominent Kirkwood gaps and a possible division into inner, middle and outer main-belt asteroids:

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A Kirkwood gap is a gap or dip in the distribution of the semi-major axes (or equivalently of the orbital periods) of the orbits of main-belt asteroids. They correspond to the locations of orbital resonances with Jupiter.

For example, there are very few asteroids with semimajor axis near 2.50 AU, period 3.95 years, which would make three orbits for each orbit of Jupiter (hence, called the 3:1 orbital resonance). Other orbital resonances correspond to orbital periods whose lengths are simple fractions of Jupiter's. The weaker resonances lead only to a depletion of asteroids, while spikes in the histogram are often due to the presence of a prominent asteroid family (see List of asteroid families).

The gaps were first noticed in 1866 by Daniel Kirkwood, who also correctly explained their origin in the orbital resonances with Jupiter while a professor at Jefferson College in Canonsburg, Pennsylvania.

Most of the Kirkwood gaps are depleted, unlike the mean-motion resonances (MMR) of Neptune or Jupiter's 3:2 resonance, that retain objects captured during the giant planet migration of the Nice model. The loss of objects from the Kirkwood gaps is due to the overlapping of the ν5 and ν6 secular resonances within the mean-motion resonances. The orbital elements of the asteroids vary chaotically as a result and evolve onto planet-crossing orbits within a few million years. The 2:1 MMR has a few relatively stable islands within the resonance, however. These islands are depleted due to slow diffusion onto less stable orbits. This process, which has been linked to Jupiter and Saturn being near a 5:2 resonance, may have been more rapid when Jupiter's and Saturn's orbits were closer together.

More recently, a relatively small number of asteroids have been found to possess high eccentricity orbits which do lie within the Kirkwood gaps. Examples include the Alinda and Griqua groups. These orbits slowly increase their eccentricity on a timescale of tens of millions of years, and will eventually break out of the resonance due to close encounters with a major planet. This is why asteroids are rarely found in the Kirkwood gaps.

Main gaps
The most prominent Kirkwood gaps are located at mean orbital radii of:
 * 1.780 AU (5:1 resonance)
 * 2.065 AU (4:1 resonance)
 * 2.502 AU (3:1 resonance), home to the Alinda group of asteroids
 * 2.825 AU (5:2 resonance)
 * 2.958 AU (7:3 resonance)
 * 3.279 AU (2:1 resonance), Hecuba gap, home to the Griqua group of asteroids.
 * 3.972 AU (3:2 resonance), home to the Hilda asteroids.
 * 4.296 AU (4:3 resonance), home to the Thule group of asteroids.

Weaker and/or narrower gaps are also found at:
 * 1.909 AU (9:2 resonance)
 * 2.258 AU (7:2 resonance)
 * 2.332 AU (10:3 resonance)
 * 2.706 AU (8:3 resonance)
 * 3.031 AU (9:4 resonance)
 * 3.077 AU (11:5 resonance)
 * 3.474 AU (11:6 resonance)
 * 3.517 AU (9:5 resonance)
 * 3.584 AU (7:4 resonance), home to the Cybele asteroids
 * 3.702 AU (5:3 resonance).

Asteroid zones
The gaps are not seen in a simple snapshot of the locations of the asteroids at any one time because asteroid orbits are elliptical, and many asteroids still cross through the radii corresponding to the gaps. The actual spatial density of asteroids in these gaps does not differ significantly from the neighboring regions.

The main gaps occur at the 3:1, 5:2, 7:3, and 2:1 mean-motion resonances with Jupiter. An asteroid in the 3:1 Kirkwood gap would orbit the Sun three times for each Jovian orbit, for instance. Weaker resonances occur at other semi-major axis values, with fewer asteroids found than nearby. (For example, an 8:3 resonance for asteroids with a semi-major axis of 2.71 AU).

The main or core population of the asteroid belt may be divided into the inner and outer zones, separated by the 3:1 Kirkwood gap at 2.5 AU, and the outer zone may be further divided into middle and outer zones by the 5:2 gap at 2.82 AU:

 * 4:1 resonance (2.06 AU)
 * Zone I population (inner zone)
 * 3:1 resonance (2.5 AU)
 * Zone II population (middle zone)
 * 5:2 resonance gap (2.82 AU)
 * Zone III population (outer zone)
 * 2:1 resonance gap (3.28 AU)

4 Vesta is the largest asteroid in the inner zone, 1 Ceres and 2 Pallas in the middle zone, and 10 Hygiea in the outer zone. 87 Sylvia is probably the largest Main Belt asteroid beyond the outer zone.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Kirkwood gap


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Tom Swift

Tom Swift is the main character of six series of American juvenile science fiction and adventure novels that emphasize science, invention, and technology. Inaugurated in 1910, the sequence of series comprises more than 100 volumes. The first Tom Swift – later, Tom Swift Sr. – was created by Edward Stratemeyer, the founder of the Stratemeyer Syndicate, a book packaging firm. Tom's adventures have been written by various ghostwriters, beginning with Howard Garis. Most of the books are credited to the collective pseudonym "Victor Appleton". The 33 volumes of the second series use the pseudonym Victor Appleton II for the author. For this series, and some later ones, the main character is "Tom Swift Jr." New titles have been published again from 2019 after a gap of about ten years, roughly the time that has passed before every resumption. Most of the series emphasized Tom's inventions. The books generally describe the effects of science and technology as wholly beneficial, and the role of the inventor in society as admirable and heroic.

Translated into many languages, the books have sold more than 30 million copies worldwide. Tom Swift has also been the subject of a board game and several attempted adaptations into other media.

Tom Swift has been cited as an inspiration by various scientists and inventors, including aircraft designer Kelly Johnson.

Inventions

In his various incarnations, Tom Swift, usually a teenager, is inventive and science-minded, "Swift by name and swift by nature." Tom is portrayed as a natural genius. In the earlier series, he is said to have had little formal education, the character modeled originally after such inventors as Henry Ford, Thomas Edison, aviation pioneer Glenn Curtiss and Alberto Santos-Dumont. For most of the six series, each book concerns Tom's latest invention, and its role either in solving a problem or mystery, or in assisting Tom in feats of exploration or rescue. Often Tom must protect his new invention from villains "intent on stealing Tom's thunder or preventing his success," but Tom is always successful in the end.

Many of Tom Swift's fictional inventions describe actual technological developments or predate technologies now considered commonplace. Tom Swift Among the Diamond Makers (1911) was based on Charles Parsons's attempts to synthesize diamonds using electric current. Tom Swift and His Photo Telephone was published in 1912. Sending photographs by telephone was not fully developed until 1925. Tom Swift and His Wizard Camera (1912) features a portable movie camera, not invented until 1923. Tom Swift and His Electric Locomotive (1922) was published two years before the Central Railroad of New Jersey began using the first diesel electric locomotive. The house on wheels that Tom invents for 1929's Tom Swift and His House on Wheels pre-dated the first house trailer by a year. Tom Swift and His Diving Seacopter (1952) features a flying submarine similar to one planned by the United States Department of Defense four years later in 1956. Other inventions of Tom's have not happened, such as the device for silencing airplane engines that he invents in Tom Swift and His Magnetic Silencer (1941).

Authorship
The character of Tom Swift was conceived about 1910 by Edward Stratemeyer, founder of the Stratemeyer Syndicate, a book-packaging business, although the name "Tom Swift" was first used in 1903 by Stratemeyer in Shorthand Tom the Reporter; Or, the Exploits of a Bright Boy. Stratemeyer invented the series to capitalize on the market for children's science adventures. The Syndicate's authors created the Tom Swift stories by first preparing an outline with the plot elements, followed by drafting and editing the detailed manuscript. The books were published using the house pseudonym "Victor Appleton". Howard Garis wrote most of the volumes of the original series; Stratemeyer's daughter, Harriet Stratemeyer Adams, wrote the last three volumes. The first Tom Swift series ended in 1941.

In 1954, Harriet Adams created the Tom Swift, Jr. series, which was published using the pseudonym "Victor Appleton II" as author. The main character Tom Swift, Junior, was described as the son of the original Tom Swift. Most of the stories were outlined and plotted by Adams. The texts were written by various writers, among them William Dougherty, John Almquist, Richard Sklar, James Duncan Lawrence, Tom Mulvey and Richard McKenna. The Tom Swift, Jr., series ended in 1971.

A third series was begun in 1981 and lasted until 1984. The rights to the Tom Swift character, along with the Stratemeyer Syndicate, were sold in 1984 to publishers Simon & Schuster. They hired New York City book packaging business Mega-Books to produce further series. Simon & Schuster has published three more Tom Swift series: one from 1991 to 1993;Tom Swift, Young Inventor from 2006 to 2007; and Tom Swift Inventors Academy from 2019 to present—eight volumes as of Depth Perception (March 2022).

Series
The longest-running series of books to feature Tom Swift is the first, which consists of 40 volumes. Tom's son (Tom Swift Jr.) was also the name of the protagonist of the 33 volumes of the Tom Swift Jr. Adventures, the 11 volumes of the third Tom Swift series, the 13 volumes of the fourth, and a half-dozen more for the most recent series, Tom Swift, Young Inventor, for a total of 103 volumes for all the series. In addition to publication in the United States, Tom Swift books have been published extensively in England, and translated into Norwegian, French, Icelandic, and Finnish.

Original series (1910–1941)
In the original series, Tom Swift lives in fictional Shopton, New York. He is the son of Barton Swift, the founder of the Swift Construction Company. Tom's mother is deceased, but the housekeeper, Mrs. Baggert, functions as a surrogate mother. Tom usually shares his adventures with close friend Ned Newton, who eventually becomes the Swift Construction Company's financial manager. For most of the series, Tom dates Mary Nestor. It has been suggested that his eventual marriage to Mary led to the series' demise, as young boys found a married man harder to identify with than a young, single one; however, after the 1929 marriage the series continued for 12 more years and eight further volumes. Regularly appearing characters include Wakefield Damon, an older man, whose dialogue is characterized by frequent use of such whimsical expressions as "Bless my brakeshoes!" and "Bless my vest buttons!"

The original Tom Swift has been claimed to represent the early 20th-century conception of inventors. Tom has no formal education after high school; according to critic Robert Von der Osten, Tom's ability to invent is presented as "somehow innate". Tom is not a theorist but a tinkerer and, later, an experimenter who, with his research team, finds practical applications for others' research; Tom does not so much methodically develop and perfect inventions as find them by trial and error.

Tom's inventions are not at first innovative. In the first two books of the series, he fixes a motorcycle and a boat, and in the third book he develops an airship, but only with the help of a balloonist. Tom is also at times unsure of himself, asking his elders for help; as Von der Osten puts it, "the early Tom Swift is more dependent on his father and other adults at first and is much more hesitant in his actions. When his airship bangs into a tower, Tom is uncharacteristically nonplussed and needs support." However, as the series progresses, Tom's inventions "show an increasingly independent genius as he develops devices, such as an electric rifle and a photo telephone, further removed from the scientific norm". Some of Tom's inventions are improvements of then-current technologies, while other inventions were not in development at the time the books were published, but have since been developed.

Second series (1954–1971)
In this series, presented as an extension and continuation of the first, the Tom Swift of the original series is now the CEO of Swift Enterprises, a four-mile-square enclosed facility where inventions are conceived and manufactured. Tom's son, Tom Swift Jr., is now the primary inventive genius of the family. Stratemeyer Syndicate employee Andrew Svenson described the new series as based "on scientific fact and probability, whereas the old Toms were in the main adventure stories mixed with pseudo-science". Three PhDs in science were hired as consultants to the series to ensure scientific accuracy. The younger Tom does not tinker with motorcycles; his inventions and adventures extend from deep within the Earth (in Tom Swift and His Atomic Earth Blaster [1954]) to the bottom of the ocean (in Tom Swift and His Diving Seacopter [1956]) to the Moon (in Tom Swift in the Race to the Moon [1958]) and, eventually, the outer Solar System (in Tom Swift and His Cosmotron Express [1970]). Later volumes of the series increasingly emphasized the extraterrestrial "space friends", as they are termed throughout the series. The beings appear as early as the first volume of the series, Tom Swift and His Flying Lab (1954). The Tom Swift Jr., Adventures were less commercially successful than the first series, selling 6 million copies total, compared with sales of 14 million copies for the first series.

In contrast to the earlier series, many of Tom Jr.'s inventions are designed to operate in space, and his "genius is unequivocally original as he constructs nuclear-powered flying labs, establishes outposts in space, or designs ways to sail in space on cosmic rays". Unlike his father, Tom Jr. is not just a tinkerer; he relies on scientific and mathematical theories, and, according to critic Robert Von der Osten, "science [in the books] is, in fact, understood to be a set of theories that are developed based on experimentation and scientific discussion. Rather than being opposed to technological advances, such a theoretical understanding becomes essential to invention."

Tom Swift Jr.'s Cold War-era adventures and inventions are often motivated by patriotism, as Tom repeatedly defeats the evil agents of the fictional nations "Kranjovia" and "Brungaria", the latter a place that critic Francis Molson describes as "a vaguely Eastern European country, which is strongly opposed to the Swifts and the U.S. Hence, the Swifts' opposition to and competition with the Brungarians is both personal and patriotic."

Third series (1981–1984)
The third Tom Swift series differs from the first two in that the setting is primarily outer space, although Swift Enterprises (located now in New Mexico) is occasionally mentioned. Tom Swift explores the universe in the starship Exedra, using a faster-than-light drive he has reverse-engineered from an alien space probe. He is aided by Benjamin Franklin Walking Eagle, a Native American who is Tom's co-pilot, best friend, and an expert computer technician, and Anita Thorwald, a former rival of Tom's who now works with him as a technician and whose right leg has been rebuilt to contain a miniature computer.

This series maintains only an occasional and vague continuity with the two previous series. Tom is called the son of "the great Tom Swift" and said to be "already an important and active contributor to the family business, the giant multimillion-dollar scientific-industrial complex known as Swift Enterprises". However, as critic Francis Molson indicates, it is not explained whether this Tom Swift is the grandson of the famous Tom Swift of the first series or still the Tom Swift Jr. of the second.

The Tom Swift of this third series is less of an inventor than his predecessors, and his inventions are rarely the main feature of the plot. Still, according to Molson, "Tom the inventor is not ignored. Perhaps the most impressive of his inventions and the one essential to the series as a whole is the robot he designs and builds, Aristotle, which becomes a winning and likeable character in its own right." The books are slower-paced than the Tom Swift Jr. adventures of the second series, and include realistic, colloquial dialogue. Each volume begins where the last one ended, and the technology is plausible and accurate.

Fourth series (1991–1993)
The fourth series featuring Tom Swift (again a "Jr.") is set mostly on Earth (with occasional voyages to the Moon); Swift Enterprises is now located in California. In the first book, The Black Dragon, it's mentioned that Tom is the son of Tom Swift Sr. and Mary Nestor. The books deal with what Richard Pyle describes as "modern and futuristic concepts" and, as in the third series, feature an ethnically diverse cast of characters.

Like the Tom Swift Jr. series, the series portrays Tom as a scientist as well as an inventor whose inventions depend on a knowledge of theory. The series differs from previous versions of the character, however, in that Tom's inventive genius is portrayed as problematic and sometimes dangerous. As Robert Von der Osten argues, Tom's inventions for this series often have unexpected and negative repercussions.

a device to create a miniature black hole which casts him into an alternative universe; a device that trains muscles but also distorts the mind of the user; and a genetic process which, combined with the effect of his black hole, results in a terrifying devolution. Genius here begins to recapitulate earlier myths of the mad scientist whose technological and scientific ambitions are so out of harmony with nature and contemporary science that the results are usually unfortunate.

The series features more violence than previous series; in The Negative Zone, Tom blows up a motel room to escape the authorities.

There was a derivative of this series featuring Tom Swift and the Hardy Boys called A Hardy Boys & Tom Swift Ultra Thriller that was published from 1992 to 1993, and only had 2 volumes released. Both books dealt with science fictional topics (time travel and aliens landing on earth).

Fifth series (2006–2007)
The fifth series, Tom Swift, Young Inventor, returns Tom Swift to Shopton, New York, with Tom as the son of Tom Swift and Mary Nestor, the names of characters of the original Tom Swift series. The series features inventions that are close to current technology "rather than ultra-futuristic". In several of the books, Tom's antagonist is The Road Back (TRB), an anti-technology terrorist organization. Tom's personal nemesis is Andy Foger, teenage son of his father's former business partner who now owns a competing (and ethically dubious) high-technology company.

Sixth series (2019-2022)
A sixth series, Tom Swift Inventors' Academy, published by Simon and Schuster, debuted in July 2019 with #1 The Drone Pursuit and #2 The Sonic Breach. A total of eight books were published, concluding with #8 Depth Perception in March 2022.

Other media
Parker Brothers produced a Tom Swift board game in 1966, although it was never widely distributed, and the character has appeared in one television show. Various Tom Swift radio programs, television series, and movies were planned and even written, but were either never produced or not released.

Cancelled films
As early as 1914, Edward Stratemeyer proposed making a Tom Swift movie, but no such movie was made. A Tom Swift radio series was proposed in 1946. Two scripts were written, but, for unknown reasons, the series was never produced. Twentieth Century Fox planned a Tom Swift feature movie in 1968, to be directed by Gene Kelly. A script was written and approved, and filming was to have begun during 1969. However, the project was canceled owing to the poor reception of the movies Doctor Dolittle and Star!; a $500,000 airship that had been built as a prop was rumored to have been sold to a midwest amusement park. Yet another movie was planned in 1974, but, again, was cancelled.

Television
Scripts were written for a proposed television series involving both Tom Swift Jr. and his father, the hero of the original book series. A television pilot show for a series to be called The Adventures of Tom Swift was filmed in 1958, featuring Gary Vinson. However, legal problems prevented the pilot's distribution, and it was never broadcast; no copies of the pilot are known to exist, though the pilot script is available. In 1977, Glen A. Larson wrote an unproduced television pilot show entitled "TS, I Love You: The Further Adventures of Tom Swift". This series was to be combined with a Nancy Drew series, a Hardy Boys series, and a Dana Girls series. Nancy Drew and the Hardy Boys were eventually combined into a one-hour program The Hardy Boys/Nancy Drew Mysteries with alternating episodes.

A Tom Swift media project finally came to fruition in 1983 when Willie Aames appeared as Tom Swift along with Lori Loughlin as Linda Craig in a television special, The Tom Swift and Linda Craig Mystery Hour, which was broadcast on July 3. It was a ratings failure. In 2007, digital studio Worldwide Biggies acquired movie rights to Tom Swift and announced plans to release a feature film and video game, followed by a television series. As of 2015, these plans had not come to fruition.

Tom Swift appeared in the episode "The Celestial Visitor" from the second season of The CW's Nancy Drew with Tian Richards portraying the character as a black, gay, billionaire inventor. The episode is a backdoor pilot for a spin-off project titled Tom Swift, in development at The CW. In August 2021, Tom Swift was ordered straight-to-series and premiered on May 31, 2022 on The CW. In February 2022, Ashleigh Murray joined the cast as Zenzi Fullington. Due to poor ratings, the series was cancelled on June 30 that year.

Depiction of race
Tom Swift and His Electric Rifle (published 1911) depicts Africans as brutish, uncivilized animals, and the white protagonist as their paternal savior. "In the book, as in America today, the black people are rendered as either passive, simple and childlike, or animalistic and capable of unimaginable violence. They are described in the book at various points as 'hideous in their savagery, wearing only the loin cloth, and with their kinky hair stuck full of sticks', and as 'wild, savage and ferocious ... like little red apes'."

Cultural influence

The Tom Swift books have been credited with assisting the success of American science fiction and with establishing the edisonade (stories focusing on brilliant scientists and inventors) as a basic cultural myth. Tom Swift's adventures have been popular since the character's inception in 1910: by 1914, 150,000 copies a year were being sold and a 1929 study found the series to be second in popularity only to the Bible for boys in their early teens. By 2009, Tom Swift books had sold more than 30 million copies worldwide. The success of Tom Swift also paved the way for other Stratemeyer creations, such as The Hardy Boys and Nancy Drew.

The series' writing style, which was sometimes adverb heavy, suggested a name for a type of adverbial pun promulgated during the 1950s and 1960s, a type of wellerism known as "Tom Swifties". Originally this kind of pun was called a "Tom Swiftly" in reference to the adverbial usage. Over time, it has come to be called a "Tom Swifty". Some examples are I lost my crutches,' said Tom lamely", and I'll take the prisoner downstairs', said Tom condescendingly."

Tom Swift's fictional inventions have apparently inspired several actual inventions, among them Lee Felsenstein's "Tom Swift Terminal", which "drove the creation of an early personal computer known as the Sol", and the taser. The name "taser" was originally "TSER", for "Tom Swift Electric Rifle". The invention was named for the central device in the story Tom Swift and His Electric Rifle (1911); according to inventor Jack Cover, "an 'A' was added because we got tired of answering the phone 'TSER'."

A number of scientists, inventors, and science fiction writers have also credited Tom Swift with inspiring them, including Ray Kurzweil, Robert A. Heinlein, and Isaac Asimov. Gone with the Wind author Margaret Mitchell was also known to have read the first series as a child. Filmmaker George Lucas shows the 16-year-old Indiana Jones reading a Tom Swift novel — and the author Edward Stratemeyer himself appearing as a character — in the episode Spring Break Adventure of the television series Young Indiana Jones.

The Tom Swift Jr. series was also a source of inspiration to many. Scientist and television presenter Bill Nye said the books helped "make me who I am", and they inspired him to launch his own young adult series. Microsoft founders Paul Allen and Bill Gates also read the books as children, as did co-founder of competing company Apple, Steve Wozniak. Wozniak, who cited the series as his inspiration to become a scientist, said the books made him feel "that engineers can save the world from all sorts of conflict and evil".

title: Tom Swift


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Valve Corporation

Valve Corporation, also known as Valve Software, is an American video game developer, publisher, and digital distribution company headquartered in Bellevue, Washington. It is the developer of the software distribution platform Steam and the game franchises Half-Life, Counter-Strike, Portal, Day of Defeat, Team Fortress, Left 4 Dead and Dota.

Valve was founded in 1996 by the former Microsoft employees Gabe Newell and Mike Harrington. Their debut game, the first-person shooter (FPS) Half-Life (1998), was a critical and commercial success and had a lasting influence on the FPS genre. Harrington left in 2000. In 2003, Valve launched Steam, followed by Half-Life 2 (2004), the episodic sequels Half-Life 2: Episode One (2006) and Episode Two (2007), the multiplayer games Team Fortress 2 (2007) and Left 4 Dead (2008), the puzzle games Portal (2007) and Portal 2 (2011) and the multiplayer online battle arena game Dota 2 (2013).

In the 2010s, Valve released fewer games and experimented with hardware and virtual reality (VR). They entered the hardware market in 2015 with the Steam Machine, a line of gaming computers, which sold poorly, and released the HTC Vive and Valve Index VR headsets. They returned to the Half-Life series in 2020 with Half-Life: Alyx, their flagship VR game. In 2022, Valve released the Steam Deck, a portable gaming system.

Valve uses a flat structure, whereby employees decide what to work on themselves. They develop games through playtesting and iteration, describing game design as a kind of experimental psychology. By 2012, Valve employed around 250 people and was reportedly worth over US$3 billion. Most of Valve's revenue comes from Steam, which controlled over half of the digital PC games market in 2011 and generated an estimated $3.4 billion in 2017.

Founding and Half-Life (1996–2003)
Valve was founded in 1996 by former Microsoft employees Gabe Newell and Mike Harrington. Newell had spent the prior 13 years at Microsoft developing Windows, including the Windows 95 port of Doom. Wanting to move onto a new venture using their shared wealth, Newell and Harrington founded Valve, L.L.C. in Kirkland, Washington, about five miles from the Microsoft campus in Redmond, on August 24, 1996, Newell's wedding day. In a break from industry style of the time, Newell did not want a company name that suggested "testosterone-gorged muscles and the 'extreme' of anything". Alternative names considered by Newell and Harrington include Hollow Box, Fruitfly Ensemble and Rhino Scar.

Valve's first game was Half-Life, a first-person shooter (FPS) with elements of horror. The development was aided by access to the Quake engine by id Software; Valve modified this engine into their GoldSrc engine. After struggling to find a publisher, Valve eventually signed with Sierra On-Line. Half-Life was released in November 1998 and was a critical and commercial success. With its realism, scripted sequences and seamless narrative, it had a lasting influence; according to IGN in 2014, the history of the FPS genre "breaks down pretty cleanly into pre-Half-Life and post-Half-Life eras".

Valve enlisted Gearbox Software to develop three expansions for Half-Life: Opposing Force (1999), Blue Shift (2001) and Decay (2001). In 1998, Valve acquired TF Software, a group that had made the popular Team Fortress mod for Quake, and remade it for GoldSrc as Team Fortress Classic in 1999. Valve released the software development kit (SDK) for the GoldSrc engine, facilitating numerous user-created mods. They acquired the developers of one popular mod, Counter-Strike, to create a standalone Counter-Strike game. Happy with Valve's success, Harrington left in 2000.

Source, Steam, and Half-Life 2 (2003–2010)
In 2003, Valve moved to Bellevue, Washington, and reincorporated as Valve Corporation. In 2010, the office moved to a larger location in Bellevue. In 2016, Valve signed a nine-floor lease in the Lincoln Square complex in downtown Bellevue, doubling the size of its offices.

Valve began developing Half-Life 2 six months after the release of the first Half-Life, using its new in-house engine, Source. With advanced physics systems and an increased focus on story and characters, it received critical acclaim upon its release in 2004. By 2011, it had sold 12 million copies. In 2002, Valve launched Steam, a digital storefront and delivery platform. Steam initially offered only Valve games, and was mandatory to install Half-Life 2, but became a publisher of third-party games. As Valve became its own publisher via Steam, it transitioned to a flat organization; outside of executive management, Valve does not have bosses, and the company uses an open allocation system, allowing employees to move between departments at will.

After having taken years to develop Half-Life 2, Valve moved to episodic development, planning to release shorter games more frequently. Half-Life 2: Episode One, the first in a planned trilogy of episodic Half-Life 2 sequels, was released in 2006. Episode Two followed in 2007, alongside the multiplayer game Team Fortress 2 and the puzzle game Portal, developed from the student project Narbacular Drop.

In January 2008, Valve announced the acquisition of Turtle Rock Studios, which was renamed Valve South. Turtle Rock developed Left 4 Dead and Left 4 Dead 2 while associated with Valve. Turtle Rock Studios later spun out of Valve again in March 2010.

Forbes estimated that Valve had grossed $70 million in 2005. Screen Digest analyst Ed Barton estimated Valve's 2010 revenue to be in the "high hundreds of millions of dollars". As of 2011, Valve had an estimated worth of $2 to 4 billion and employed 250 people; according to Newell, this made it more profitable per employee than Google or Apple. Most of Valve's revenue comes from Steam, which controlled 50 to 70% of the market for downloaded PC games in 2011.

Transition to services (2010–2014)
In 2009, Valve hired IceFrog, the developer of Defense of the Ancients, a Warcraft III mod. IceFrog led the development of a sequel not associated with the Warcraft elements, Dota 2, released in 2013. Alongside Dota 2 in 2011, Valve started The International, an annual esports tournament for Dota 2 with a prize pool supported by Valve and funds from microtransactions from battle passes purchased by players. Valve released Portal 2 in April 2011. As with the original Portal, Valve employed a Digipen student team to help develop it; the team behind Tag: The Power of Paint implemented the new gel gameplay.

In December 2012, Valve acquired Star Filled Studios, a two-person studio, to open a San Francisco office. Valve ended the operation in August 2013 when they decided it had little benefit. At the 2013 D.I.C.E. Summit, Newell announced that he and the film director J. J. Abrams were collaborating to produce a Half-Life or Portal film, as well as a possible game.

In the 2010s, Valve released fewer games and invested in hardware development. Newell intended to make Valve more like Nintendo, which develops games in tandem with hardware, allowing them to create innovative games such as Super Mario 64. Valve initially focused on augmented reality, but in 2013 Newell laid off many staff to focus on virtual reality (VR). In 2015, Valve released the Steam Machine, a line of gaming computers, which sold poorly.

Media commentators speculated that Valve's transition to service provider with Steam, which generated an estimated $3.4 billion in 2017, had driven it away from game development. Valve canceled games including numerous Half-Life projects (including Episode Three), Left 4 Dead 3, a Soulslike game, and a voxel-based game, A.R.T.I. Additional VR projects included SimTrek, developed by members of the Kerbal Space Program development team, and a new VR device, Vader, that was determined to be too costly for consumers. According to the designer Robin Walker, the abundance of projects that failed to gain traction, with no shared vision, damaged morale. Many players grew frustrated in anticipation of a new Half-Life game.

Source 2, virtual reality and Half-Life: Alyx (2015–present)
Valve announced the Source 2 engine in March 2015 and ported Dota 2 to it that September. That year, Valve collaborated with the electronics company HTC to develop the HTC Vive, a VR headset released in 2016. Valve experimented with VR games, and in 2016 released The Lab, a collection of VR minigames.

Valve recognized that many players wanted a more ambitious VR AAA game, and began exploring the development of a major VR game. They developed several prototypes, with three further VR projects under development by 2017. Finding that the portal systems of their puzzle series Portal were disorienting in VR, they settled on Half-Life. Walker said that Half-Life 3 had been a "terrifyingly daunting prospect", and the team saw VR as a way to return to the series.

Full development of a VR Half-Life game started around late 2016, with the largest team in Valve's history. Valve acquired the 3D audio software developer Impulsonic in January 2017. In April 2018, Valve acquired the independent developer Campo Santo, known for the 2016 adventure game Firewatch. Campo Santo planned to develop its own games under Valve, though they initially helped develop Half-Life: Alyx.

In November 2018, Valve released Artifact, a digital collectible card game based on Dota 2, with design by Richard Garfield, the creator of Magic: The Gathering. Artifact had unusual pay-for mechanics to acquire new cards, and did not draw a large playerbase, losing 95% of players months after release. In April 2021, Valve abandoned efforts to reboot the project, saying they had not found enough interested players to justify development. In June 2019, Valve released its second-generation VR hardware, the Valve Index. They also released Dota Underlords into early access, an auto battler based on a Dota 2 community-created mode Dota Auto Chess.

In March 2020, Valve released Half-Life: Alyx, a VR game. It received acclaim and was described as VR's first killer app. Newell said in January 2021 that the success of Alyx created desire within the company to develop more games, and that several were under development. Valve collaborated with Netflix for Dota: Dragon's Blood, an animated television series based on Dota, which premiered in March 2021. In February 2022, Valve released the Steam Deck, a portable game system that runs on SteamOS. In March 2023, Valve announced Counter-Strike 2. It is expected to feature major technical improvements.

Structure
Initially, Valve used a hierarchical structure more typical of other development firms, driven by the nature of physical game releases through publishers that required tasks to be completed by deadlines. However, as Valve became its own publisher via Steam, it found the hierarchal structure was hindering progress.

After completing Half-Life 2, Valve transitioned to a flat organization; outside of executive management, Valve does not have bosses, and uses an open allocation system. Valve's marketing manager, Doug Lombardi, said: "Nobody writes a design doc and hands it to somebody and says, 'you go build this'. It's the teams that are coming up with the ideas and pushing in the directions that they want to take the product." This approach allows employees to work on whatever interests them, but requires them to take ownership of their product and mistakes they may make, according to Newell. Newell recognized that this structure works well for some but that "there are plenty of great developers for whom this is a terrible place to work".

Although Valve has no bosses, some employees hold more influence due to seniority or relationships. De facto project leads became "centralized conduits" for organization and sharing information, and decisions are made collectively. Valve uses an "Overwatch" process to gather feedback from senior members, which teams may use or ignore.

The success of Steam means that Valve is not dependent on the success of its games. The lack of organization structure has led to project cancellations, as it can be difficult to convince other employees to work on them. In 2020, Valve acknowledged that this made it difficult to gather momentum and had slowed their output during the 2010s. Their VR projects and Half-Life: Alyx became a turning point, setting short-term studio-wide goals to focus the company. According to Walker, "We sort of had to collectively admit we were wrong on the premise that you will be happiest if you work on something you personally want to work on the most."

In January 2023, People Make Games released a report on Valve's corporate structure and culture, based on interviews with several current and former employees. They found that Valve's flat structure and stack-ranking compensation system created a poor release record and a lack of employee diversity.

As part of Wolfire Games' lawsuit over Steam policies, case documents revealed details related to Valve's employee structure. Starting with 60 employees in 2003, the company grew to around 350 employees around 2012 and remained around this number through 2021. Up through 2010, the employees were categorized in three areas, adminstration, game development, and Steam development; in 2011, a new hardware development category was added.

Valve time
Valve time is an industry term used jokingly with game releases from Valve, used to acknowledge the difference between the "promised" date for released content stated by Valve and to the "actual" release date; "Valve Time" includes delays but also includes some content that was released earlier than expected. Valve itself has fully acknowledged the term, including tracking known discrepancies between ideal and actual releases on their public development wiki and using it in announcements about such delays. Valve ascribes delays to their mentality of team-driven initiatives over corporate deadlines.

Playtesting
Valve playtests its games extensively, starting from the beginning of development, and iterates based on the results. Its website states: "We believe that all game designers are, in a sense, experimental psychologists." The Valve writer Chet Faliszek said he initially blamed testers when they failed to engage with designs as expected, but changed his mind when multiple testers had the same problem: "By the third or fourth time, all of a sudden you're realizing, 'I'm an idiot. This is pretty obvious this doesn't work. It's not their fault, it's our fault.'" He gave an example from the development of Left 4 Dead, wherein a texture change caused every tester to miss a ladder and become stuck.

Walker said playtesting helped Valve maximize the experience for players. For example, when something "incredibly cool" occurs by chance during a playtest, the developers attempt to have it occur for every player. Newell contrasted this approach to that of Warren Spector, whose open-ended games are designed to be replayed with different outcomes: "You spend all of this time to build stuff that most players will never ever ever see ... If only one per cent of your customers see this cool thing that takes five per cent of your development budget, that's not a good use of resources."

Games
Valve is the main developer and publisher of the single-player Half-Life and Portal games and the multiplayer games Counter-Strike, Team Fortress 2, Dota 2, Day of Defeat, and Artifact. Valve also published the multiplayer game Left 4 Dead and developed and published Left 4 Dead 2. Unreleased and canceled Valve games include the fantasy role-playing game Prospero and numerous Half-Life projects, including Episode Three. Valve worked with Arkane Studios on The Crossing, which was canceled in May 2009.

Steam
Valve announced Steam, its digital distribution service, at the 2002 Game Developers Conference. It was launched in September 2003 and was first used to deliver patches and other updates to Valve's online games.

On August 1, 2012, Valve announced revisions to the Steam Subscriber Agreement (SSA) to prohibit class action lawsuits by users against the service provider. By July 2014, there were over 3,400 games available on Steam, with over 150 million registered accounts by January 2018.

Alongside these changes to the SSA, the company also declared publicly the incorporation of Valve S.a.r.l., a subsidiary based in Luxembourg. Valve set up a physical office in Luxembourg Kirchberg. According to Valve's project manager Mike Dunkle, the location was chosen for eCommerce capabilities and infrastructure, talent acquisition, tax advantages and central geographic location – most major partners are accessible, 50% within driving distance.

Valve S.a.r.l. was used to sell games to UK users to avoid paying the full 20% value-added tax (VAT). The tax loophole was expected to close on January 1, 2015. In December 2015, the French consumer group UFC Que Choisir initiated a lawsuit against Valve for several of their Steam policies that conflict or run afoul of French law. One of the reasons was for using the tax loophole. Valve S.a.r.l. ceased business on January 1, 2017, with the main company taking over EU sales again. In August 2017, Valve announced that Steam had reached over 67 million monthly and 33 million daily active users on the platform.

Steam Machine
Newell has been critical of the direction that Microsoft has taken with making Windows a closed architecture similar to Apple's products, and has stated that he believes that the changes made in Windows 8 are "a catastrophe for everyone in the [personal computer] space". Newell identified the open-source Linux platform as an ideal platform for Steam and said the only thing holding back its adoption is the lack of games.

In 2012, Valve announced that they were working on a console/PC hybrid for the living room, dubbed by media as the "Steam Box". A precursor to such a unit is SteamOS, a freely available Linux-based operating system that builds upon the Steam client functionality that includes media services, live streaming across home networks, game sharing within families, and parental controls. SteamOS was officially announced in September 2013 as the first of several announcements related to the Steam Machine platform as well as their unique game controller. In May 2014, Valve announced that the company's own SteamOS-powered Steam Machine would be delayed until 2015 due to problems with the game controller. In 2015, Alienware, ZOTAC, and CyberPowerPC launched their versions of the Steam Machine. By June 2016, fewer than half a million had been sold. While the Steam Machine line has been effectively canceled, Valve continued to manufacture and sell Steam Controllers until late November 2019, and publishes both mobile apps and software for the Steam Link, allowing in-home streaming.

Valve Index and virtual reality
At the Game Developers Conference in March 2015, Valve and Taiwanese electronics company HTC unveiled SteamVR and the HTC Vive—a virtual reality platform and a virtual reality headset. The platform would be distinguished by its "Lighthouse" motion tracking system, where sensors on the headset and its included motion controllers read the position of two base station devices mounted in the play area. This would allow for "room-scale" VR experiences, where the player would not be required to remain in a stationary position in front of a camera and would be able to freely walk around the space.

In November 2017, Microsoft added beta support for the SteamVR service for Windows Mixed Reality headsets. In June 2019, Valve released their own VR headset, known as the Valve Index, positioned as a higher-end device with wider field of view and higher refresh rate. They were accompanied by updated motion controllers, which are strapped against the user's palms and have sensors for detecting input pressure and individual fingers.

Steam Deck
Announced in July 2021, the Steam Deck is a hybrid game console similar to the Nintendo Switch. It is primarily a handheld device that supports playing of Steam games, but through a separate dock unit, the console can output to an external monitor and use external power, networking, and USB accessories connected to the dock. The hardware is based on customized AMD Zen 2 and RDNA 2 chipsets. Units started shipping in February 2022.

PowerPlay
PowerPlay was a technological initiative headed by Valve and Cisco Systems to decrease the latency for online games, announced in January 2000. It was described as a set of protocols and deployment standards at the router level to improve performance. It was claimed that a player with 1000 ms ping was able to play against another player on a LAN connection with no noticeable disadvantage. Initially the protocol was to be released with PowerPlay 1.0 focusing on quality of service (QoS) and later a revision, PowerPlay 2.0 that would focus on functionality. Cisco and Valve intended to deliver a single dial-up service in Q1 2000 in the United States with a 30-day free trial with a bundled copy of Team Fortress modified to support PowerPlay.

The standard was to involve purchasing PowerPlay approved Cisco hardware and infrastructure that had adequate bandwidth and QoS standards that prioritize PowerPlay gaming packets at all others' expense. Newell conceded that Internet service providers (ISPs) would bear the brunt of this expense: "The ISPs are going to need to spend a fair amount of money to be compliant with PowerPlay. But how they get that back is up to them. Some will have a tiered service, and some will just try to recoup their investment through reduced customer churn and customer acquisition." Despite never deploying the dial-up plan featuring PowerPlay 1.0, Valve announced in January 2001 that the standard had indeed been finalized. 12 months after its announcement, PowerPlay was abandoned.

Pipeline
In July 2013, Valve announced Pipeline, an intern project consisting of ten high school students working together to learn how to create video game content. Pipeline serves to discuss and answer questions that teenagers often ask about the video game industry, and see if it is possible to train a group of teenagers with minimal work experience to work for a company like Valve. The latter purpose breaks Valve's tradition of employing experienced developers, as the company is not good at "teaching people straight out of school".

Valve Corporation v. Vivendi Universal Games
Between 2002 and 2005, Valve was involved in a complex legal dispute with its publisher, Vivendi Universal Games (under Vivendi's brand Sierra Entertainment). Valve had entered into a publishing agreement with Sierra to release Half-Life and subsequent games in 1997, with the contract giving Sierra some intellectual property (IP) rights to Valve's games. After Valve began development of Half-Life 2, it agreed a new contract with Sierra in 2001, removing these rights from Sierra and giving Valve some rights for digital distribution. Internally, Valve started work on Steam as a means to digitally distribute these games, and first revealed this project at the March 2002 Game Developers Conference.

By August 2002, Valve had found that Sierra was distributing copies of their games to Internet cafes against the terms of their contracts and filed a lawsuit against Sierra and Vivendi. In addition to claims of copyright infringement, Valve asserted that Sierra breached contract by withholding royalties and delaying the release of Counter-Strike: Condition Zero until after the holiday season. Vivendi and Sierra countersued, stating that Valve had misrepresented their position in the revised 2001 contract since they had been working on Steam at that point as a means to circumvent the publishing agreement. Vivendi sought intellectual property rights to Half-Life and a ruling preventing Valve from using Steam to distribute Half-Life 2.

On November 29, 2004, Judge Thomas Samuel Zilly of the U.S. District Court for the Western District of Washington ruled in favor of Valve. The ruling stated that Vivendi Universal and its affiliates (including Sierra) were not authorized to distribute Valve games, either directly or indirectly, through cyber cafés to end users for pay-to-play activities pursuant to the parties' publishing agreement. In addition, Judge Zilly ruled that Valve could recover copyright damages for infringements without regard to the publishing agreement's limitation of liability clause. Valve posted on the Steam website that the companies had come to a settlement in court on April 29, 2005. Electronic Arts announced on July 18, 2005, that they would partner with Valve in a multi-year deal to distribute their games, replacing Vivendi Universal. As a result of the trial, the arbitrator also awarded Valve $2,391,932.

Valve Corporation v. Activision Blizzard
In April 2009, Valve sued Activision Blizzard, which acquired Sierra Entertainment after a merger with its parent company, Vivendi Universal Games. Activision had allegedly refused to honor the Valve v. Vivendi arbitration agreement. Activision had only paid Valve $1,967,796 of the $2,391,932 award, refusing to pay the remaining $424,136, claiming it had overpaid that sum in the past years.

Dota intellectual property ownership
Defense of the Ancients (DotA) was a landmark mod first released in 2003 that created the basis of the genre of multiplayer online battle arena (MOBA). It was originally developed by Kyle Sommer (who goes by the alias Eul) within Blizzard Entertainment's Warcraft III: Reign of Chaos via its world editor, and spawned several similar efforts, notably DotA-Allstars. While there had been several that contributed to DotA-Allstars, the project was managed primarily by Steve "Guinsoo" Feak, and later by "IceFrog". IceFrog was eventually hired by Valve in 2009, with the rights to the DotA intellectual property being sold to Valve the following year. Eul was also hired into Valve by 2010. Valve then subsequently filed trademarks towards a sequel to DotA, titled Dota 2. DotA-Allstars, LLC, a group of former contributors to the DotA-Allstars project, filed an opposing trademark in August 2010 to contest Valve's claim it owned the property rights.

DotA-Allstars, LLC was eventually acquired by Blizzard to start development of Blizzard All-Stars. Blizzard took over the trademark challenge. The United States Patent & Trademark Office initially ruled in Valve's favor. By this point, Riot Games had hired Guinsoo to help develop their own MOBA, League of Legends. As with IceFrog, Feak transferred his rights to the Dota property to Riot, who in turn sold those to Blizzard. Blizzard filed a lawsuit against Valve to challenge Valve's ownership, pitting the rights assigned through IceFrog to Guinsoo at odds. The case Blizzard Entertainment v. Valve Corporation was settled out of court in May 2012; Valve retained the right to use Dota commercially, while Blizzard reserved the right for fans to use Dota non-commercially. Blizzard changed the names of its own projects to remove the Dota term, and renamed Blizzard All-Stars as Heroes of the Storm. Valve's Dota 2 was released in 2013.

In 2014, mobile developers Lilith and released their games Dota Legends and Heroes Charge, respectively. Both were influenced by Dota and the sequels. In 2017, Valve and Blizzard took joint action against these companies, citing copyright issues related to the Dota names. argued that the Dota games were a collective work and could not be copyrighted by anyone in particular, but the presiding judge, Charles R. Breyer, felt that, due to the trio's actions as maintainers of the Dota mods, they had a rightful copyright claim to this. Separately, Lilith and argued that Eul had, in a forum post from September 2004, assigned an open-source copyright license to Dota, which would make Valve and Blizzard's copyright claims void. The case was later heard by a jury.

ACCC v. Valve Corporation
The Australian Competition & Consumer Commission (ACCC) announced it was taking action against Valve in 2014. On March 29, 2016, Valve was found guilty of breaching Australian consumer law because:
 * Valve claimed consumers were not entitled to a refund for digitally downloaded games purchased from Valve via the Steam website or Steam Client (in any circumstances);
 * Valve had excluded statutory guarantees and/or warranties that goods would be of acceptable quality; and
 * Valve had restricted or modified statutory guarantees and/or warranties of acceptable quality.

During the prosecution of this case, Valve implemented a refund policy for Steam purchases, but the case still reviewed Valve's actions prior to the onset of the lawsuit. The court overseeing the case sided with the ACCC in assigning a A$3 million (about US$2.1 million) fine against Valve in December 2016, as well as requiring Valve to inform Australian consumers of their rights when purchasing games from Steam. Valve appealed the court's determination that it "engaged in misleading or deceptive conduct and made false or misleading representations about consumer guarantees", as well as seeking to appeal the fine, but the Australian higher courts rejected the appeals in December 2017. In January 2018, Valve filed for a "special leave" of the court's decision, appealing to the High Court of Australia. The High Court dismissed this claim in April 2018, asserting that Valve still was liable under Australian law since it sold products directly to its citizens.

UFC Que Choisir v. Valve Corporation
Consumer rights group UFC Que Choisir, based in France, filed a lawsuit against Valve in December 2015, claiming users should be able to resell their software. The High Court of Paris ruled in favor of UFC Que Choisir in September 2019, stating that Valve must allow the resale of Steam games. Valve stated it will appeal the decision.

Skins gambling
Valve was named as a defendant in two lawsuits in June and July 2016 related to third-party gambling sites that use the Steamworks API to allow betting with the virtual currency of cosmetic weapon replacement textures, better known as "skins", from Counter-Strike: Global Offensive, which through these sites can be converted from or to real-world money. Both suits assert Valve aiding in underaged gambling. Valve subsequently stated it has no commercial ties with these sites, and that it would demand these sites cease their use of the Steamworks API as they violate the authorized use policies. In October 2016, the Washington State Gambling Commission required Valve to stop the use of virtual skins for gambling on Steam, stating they would face legal repercussions if they failed to co-operate. On October 17, 2016, Valve sent a letter to the Washington State Gambling Commission stating that they had "no business relationship with such gambling sites", asserting that they come into existence, operate, and go out of existence without their knowledge and consent, adding that they were not aware of any such law that Steam or any of their games were violating.

Anti-competitive practices
In February 2017, the European Commission began investigating Valve and five other publishers—Bandai Namco Entertainment, Capcom, Focus Home Interactive, Koch Media and ZeniMax Media—for anti-competitive practices, specifically the use of geo-blocking through the Steam storefront and Steam product keys to prevent access to software to citizens of certain countries. Such practices would be against the Digital Single Market initiative by the European Union. While the other five companies named are in stages of settling with the EU as of August 2019, Valve has stated it plans to fight the charges, asserting that geo-blocking affects less than 3% of its games, and that it had turned off such geo-blocking within the EU in 2015.

In January 2021, five gamers filed a proposed class-action antitrust lawsuit in California against Valve, alleging that the company "abuses the Steam platform's market power" by requiring game developers and publishers to enter into a 'most favored nation' agreement with Valve, restricting their ability to sell games for less on other platforms and thereby preventing price competition.

In May 2021, Wolfire Games filed a proposed class-action antitrust lawsuit against Valve, alleging that the company exerts monopoly power over the PC gaming market and uses its "gatekeeper role" to "wield extreme power over publishers of PC Desktop Games" and to extract "an extraordinarily high cut from nearly every sale that passes through its store." Although a motion by Valve to dismiss the original lawsuit was granted in November 2021, Wolfire was allowed to file a revised complaint, and in May 2022 US District Court Judge John C. Coughenour ruled that that lawsuit could proceed, finding that Wolfire's allegations were "sufficient to plausibly allege unlawful conduct."

In June 2024, Vicki Shotbolt, a children's digital rights activist, filed a lawsuit with the Competition Appeal Tribunal in the UK that accuses Valve of "rigging the market" for PC games, alleging that Valve used its market dominance to overcharge 14 million people in the UK and seeking damages of £22 to £44 per affected customer, or £656 million in total.

Discrimination lawsuit
In 2016, a former employee filed a suit against Valve alleging poor working conditions and harassment. The jury ruled in favor of Valve in 2017.

title: Valve Corporation


text:
Gesso

Gesso ('chalk', from the gypsum, from γύψος), also known as "glue gesso" or "Italian gesso", is a white paint mixture used to coat rigid surfaces such as wooden painting panels or masonite as a permanent absorbent primer substrate for painting. It consists of a binder mixed with chalk, gypsum, pigment, or any combination of these.

Gesso is used in painting as a preparation for any number of substrates such as wood panels, canvas and sculpture as a base for paint and other materials that are applied over it.

Characteristics
The colour of gesso is usually white or off-white. Its absorbency makes it work with all painting media, including water-based media, different types of tempera and oil paint.

Mixing and applying it is a craft in itself, as it is usually applied in ten or more extremely thin layers. The hide glue mixture used to make the traditional gesso is rather brittle and susceptible to cracking, thus making it suitable for rigid surfaces only.

When painting, there are several advantages to using gesso. It provides a strong foundation for the paint to adhere to, prevents the paint from soaking into the surface, and can also be used to achieve a desired texture or surface finish. Furthermore, gesso can help to extend the life of a painting by acting as a barrier to protect it from moisture, dust, and UV rays.

Composition

Gesso is traditionally a mix of an animal glue binder (usually rabbit-skin glue), chalk, and white pigment.

For priming flexible canvas, an emulsion of gesso and linseed oil, also called "half-chalk ground", is used.

Acrylic gesso is a mixture of white pigment and some kind of filler (chalk, silica, etc.) and acrylic resin dispersed in water. It produces a soft, flexible non-absorbent surface that is technically not gesso (although it is commonly called that by its manufacturers). It can contain calcium carbonate (CaCO3) to increase the absorbency of the primer coat as well as titanium dioxide or "titanium white" as a whitening agent. It is sold premixed for both sizing and priming panels and flexible canvas for painting. Art supply manufacturers market canvases pre-primed with acrylic gesso. Acrylic gesso can be colored, either commercially by replacing the titanium white with another pigment, such as carbon black, or by the artist directly, with the addition of an acrylic paint. Acrylic gesso can be odorous, due to the presence of ammonia or formaldehyde, which are added in small amounts as preservatives. Acrylic gesso's non-absorbent acrylic polymer base makes it incompatible with media that require an absorbent substrate, such as egg tempera. The Painter's Handbook notes a problem with using oil paints over an acrylic gesso ground instead of a traditional oil ground, citing a mismatch in flexibility that over time could cause the oil paint to delaminate.

Uses
Gesso is used by sculptors to prepare the shape of a final sculpture (fused bronze) or directly as a material for sculpting. Gesso can also be used as a layer between sculpted wood and gold leaf. In this case, a layer of refined and coloured clay called 'bole' is used to cover the gesso before applying the gold. Bole is usually red in colour.

It is also used as a base on three-dimensional surfaces for the application of paint or gold leaf.

title: Gesso


text:
User:Psychofish

Hello.

Some pages I seem to have edited at some point:
 * Architecture
 * Final Fantasy (and other Video games)
 * The Simpsons
 * and other randomness.

New stuff.
 * Telegraph Avenue
 * Coyote Ugly

Photos
I like photography. I take a lot of photos of things which aren't getting used all that much, so contributing them to Wikipedia seems like a good use for them. I will try to keep a list of my photos here...

 * Mission San Jose in Fremont, California
 * The Getty Center
 * Coyote Ugly Saloon

title: User:Psychofish


text:
User talk:Psychofish

Hello there, welcome to the 'pedia! I hope you like the place and decide to stay. If you need any questions answered about the project then check out Help or drop me a line. Cheers! --maveric149

AfD nomination of Pill Hill, California
Pill Hill, California, an article you created, has been nominated for deletion. We appreciate your contributions. However, an editor does not feel that Pill Hill, California satisfies Wikipedia's criteria for inclusion and has explained why in the nomination space (see also "What Wikipedia is not" and the Wikipedia deletion policy). Your opinions on the matter are welcome; please participate in the discussion by adding your comments at Articles for deletion/Pill Hill, California and please be sure to sign your comments with four tildes ( ~ ). You are free to edit the content of Pill Hill, California during the discussion but should not remove the articles for deletion template from the top of the article; such removal will not end the deletion discussion. Thank you. szyslak 11:37, 9 November 2007 (UTC)
 * Oh hey, I noticed you've been here since 2002! That easily makes you one of Wikipedia's longest-serving editors, even though you only edit once every two or three years. Amazing, isn't it? szyslak  12:08, 9 November 2007 (UTC)

Final Fantasy/Final Fantasy Tactics listed at Redirects for discussion
An editor has asked for a discussion to address the redirect Final Fantasy/Final Fantasy Tactics. Since you had some involvement with the Final Fantasy/Final Fantasy Tactics redirect, you might want to participate in the redirect discussion if you have not already done so. ZXCVBNM (TALK) 03:10, 15 April 2018 (UTC)

title: User talk:Psychofish