Darkover is the planet that gives its name to the Darkover series of science fiction - fantasy novels and short stories by Marion Zimmer Bradley and others published since 1958. According to the novels, Darkover is the only habitable planet of seven orbiting a fictional red giant star called Cottman.
123-405: Bradley describes Cottman's Star as a red giant , around which seven planets orbit. Among these, Cottman IV, known to its inhabitants as Darkover, is the only habitable planet. The three inner planets and two outer planets are not habitable. Cottman V is an ice planet that while not toxic to humans, cannot naturally support a self-sustaining human population. Like Cottman V, Darkover
246-471: A chieri gives one to his human lover so she can call on him if necessary. A matrix stone can be attuned to one person, who will always carry it with him and cannot lose it because he always knows where it is. If it is forcibly removed from him, he may go into shock and die. As related in The Bloody Sun , a small matrix stone can be attuned to a person and used as a lock on a box, and only the person to whom
369-456: A protoplanetary disk and powered mainly by the conversion of gravitational energy. The period of gravitational contraction lasts about 10 million years for a star like the sun, up to 100 million years for a red dwarf. Early stars of less than 2 M ☉ are called T Tauri stars , while those with greater mass are Herbig Ae/Be stars . These newly formed stars emit jets of gas along their axis of rotation, which may reduce
492-467: A stellar wind of particles that causes a continual outflow of gas into space. For most stars, the mass lost is negligible. The Sun loses 10 M ☉ every year, or about 0.01% of its total mass over its entire lifespan. However, very massive stars can lose 10 to 10 M ☉ each year, significantly affecting their evolution. Stars that begin with more than 50 M ☉ can lose over half their total mass while on
615-464: A "screen" by placing several jewels within glass in a pattern that they determine on an ad hoc basis, depending on the purpose of the screen. This can magnify telepathic powers even more. A screen cannot be managed by a single matrix user. The geological survey conducted The Bloody Sun is accomplished by making and using such a screen; in Sharra's Exile and Two To Conquer , a screen is used to teleport
738-520: A Tower for training advances through degrees of competence: first Monitor, then levels of Mechanic. Each degree requires an oath to do no harm and not abuse laran . First, a trainee learns to set up "barriers" to keep his thoughts from being read against his will, and to keep from "broadcasting" his thoughts and feelings. The next stage of training involves learning how to read one's own physiological symptoms such as heartbeat, respiration and body temperature, and (with permission) to read those of others. Once
861-546: A blue crystal that Jeff wears as a matrix. He is mistaken by several Darkovan natives for a member of the Comyn aristocracy. Jeff tries staring into his matrix crystal and hears voices saying that he must find his way, unaided. Defying orders, he follows his instincts into the Old Town. He arrives at the Alton townhouse and meets Kennard Alton, Taniquel, and Auster. They tell him he has passed
984-484: A brief period of carbon fusion before the core becomes degenerate. During the AGB phase, stars undergo thermal pulses due to instabilities in the core of the star. In these thermal pulses, the luminosity of the star varies and matter is ejected from the star's atmosphere, ultimately forming a planetary nebula. As much as 50 to 70% of a star's mass can be ejected in this mass loss process. Because energy transport in an AGB star
1107-491: A burst of electron capture and inverse beta decay . The shockwave formed by this sudden collapse causes the rest of the star to explode in a supernova. Supernovae become so bright that they may briefly outshine the star's entire home galaxy. When they occur within the Milky Way, supernovae have historically been observed by naked-eye observers as "new stars" where none seemingly existed before. A supernova explosion blows away
1230-410: A continuous image due to the effect of refraction from sublunary material, citing his observation of the conjunction of Jupiter and Mars on 500 AH (1106/1107 AD) as evidence. Early European astronomers such as Tycho Brahe identified new stars in the night sky (later termed novae ), suggesting that the heavens were not immutable. In 1584, Giordano Bruno suggested that the stars were like
1353-557: A counterforce. Bradley noted that most of the fan fiction she received was inspired by the Renunciates, and that she had met individuals who had taken Renunciate-style names or were attempting to live in women's communes inspired by the Renunciate guildhouses. A Renunciate takes an oath, and thereafter is known only by her first name and the name of her mother, with the connecting word "n'ha", meaning "daughter of". The woman who administers
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#17328559994081476-440: A difference between " fixed stars ", whose position on the celestial sphere does not change, and "wandering stars" ( planets ), which move noticeably relative to the fixed stars over days or weeks. Many ancient astronomers believed that the stars were permanently affixed to a heavenly sphere and that they were immutable. By convention, astronomers grouped prominent stars into asterisms and constellations and used them to track
1599-714: A few years. This results in a Comyn adult having "foster-brothers" and "foster-sisters". One example of this is Regis Hastur and Lew Alton. Regis lived at Armida during part of his childhood. The Comyn families are: Commoners are the population of Darkover that are not members of a Comyn clan or family. In general, they are portrayed as less educated than the Comyn, hard-working, shrewd and honorable, although some are members of bandit gangs. Some of them are fairly wealthy, owning lands and raising crops or animals, or having successful businesses, such as tailoring and dressmaking, leatherworking and other crafts, milling and cheesemaking, or inn-keeping. They form their own councils and petition
1722-659: A focus and a way to magnify laran . Bradley's fictional world is populated with an intelligent species, the Chieri , already ancient and in decline when the human colonists arrive. As the series developed, she introduced three other sapient native species—the Trailmen, the Forge-Folk, and the Catmen—as well as two genetically engineered sapient species—the Cralmac and Kyrri. One additional species
1845-522: A genetic basis for the development of laran on Darkover, noting that the original population of the colony derived overwhelmingly from north-west Europe (the Scottish highlands, Ireland and the Basque country) where a belief in supernatural abilities such as the second sight is common, and red hair is common as well. A matrix jewel or "starstone" provides a focus and a way to magnify laran . In Darkover Landfall ,
1968-531: A man locks up his market stall, and the yet unnamed narrator, a Terran woman in Darkovan clothing, thinks he is prosperous, because "he can afford a Terran metal lock". Since some men carry swords, and most men and many women carry knives, presumably made of iron, this seems to be somewhat contradictory. Perhaps it is the Terran craftsmanship and technology, not the metal, that makes the lock valuable. In The Bloody Sun ,
2091-471: A mechanic, notices that the hinge on a door is beginning to rust, and, taking out his matrix, he stops it. Greater skill is required to perform tasks such as refining metals or causing rain to fight a forest fire. Despite all the things that can be done with laran , it is not wise to use it for everything; in The Bloody Sun Rannirl, a Level 2 Mechanic, repairs a leaky roof at Arilinn by climbing onto
2214-477: A mining survey faster and better than the Terrans. In the introduction to Free Amazons of Darkover , Bradley wrote that her Renunciates have become "the most attractive and controversial of my creations". The Guild of Oath-Bound Renunciates, called Free Amazons and com'hi letzii in earlier books, are women who have opted out of Darkover's traditional gender-based roles , including marriage, obligations to clan, and
2337-517: A mountain-dwelling bird-like race, of questionable intelligence, who are susceptible to the effects of "ghost winds". Though they are mentioned as a background element in many of the books, the Ya-men are a critical plot element in Two to Conquer , The Winds of Darkover , and Cynthia McQuillin's The Forest from The Keeper's Price . In A Darkover Retrospective , Bradley says, "... I have no idea what
2460-509: A much larger gravitationally bound structure, such as a star cluster or a galaxy. The word "star" ultimately derives from the Proto-Indo-European root "h₂stḗr" also meaning star, but further analyzable as h₂eh₁s- ("to burn", also the source of the word "ash") + -tēr (agentive suffix). Compare Latin stella , Greek aster , German Stern . Some scholars believe the word is a borrowing from Akkadian " istar " ( Venus ). "Star"
2583-539: A net release of energy. Some massive stars, particularly luminous blue variables , are very unstable to the extent that they violently shed their mass into space in events supernova impostors , becoming significantly brighter in the process. Eta Carinae is known for having underwent a supernova impostor event, the Great Eruption, in the 19th century. As a star's core shrinks, the intensity of radiation from that surface increases, creating such radiation pressure on
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#17328559994082706-476: A part of the Empire. Hastur states that the decision of the Comyn was to preserve the Darkovan way of life and not become another satellite state of the Empire. Valdrin counters that Terran technology needs to be adopted since Darkover's matrix technology has been declining and Terran technology can replace it, or Darkover might sink into another Age of Chaos. This is a major plot point, as Arilinn Tower then engages to do
2829-527: A person from another star system. In Sharra's Exile , the Keeper Ashara explains that matrix mechanics , that is, the scientific use of laran amplified by matrix stones, is the first of the non-causal sciences. The Towers are the centers of the use of laran and schools for those who are learning to use their laran . A designated person is always on duty ("in the relays") to exchange news and requests for help telepathically with other Towers. At least once,
2952-463: A series of star maps and applied Greek letters as designations to the stars in each constellation. Later a numbering system based on the star's right ascension was invented and added to John Flamsteed 's star catalogue in his book "Historia coelestis Britannica" (the 1712 edition), whereby this numbering system came to be called Flamsteed designation or Flamsteed numbering . The internationally recognized authority for naming celestial bodies
3075-601: A set of nominal solar values (defined as SI constants, without uncertainties) which can be used for quoting stellar parameters: The solar mass M ☉ was not explicitly defined by the IAU due to the large relative uncertainty ( 10 ) of the Newtonian constant of gravitation G . Since the product of the Newtonian constant of gravitation and solar mass together ( G M ☉ ) has been determined to much greater precision,
3198-499: A star begins with gravitational instability within a molecular cloud, caused by regions of higher density—often triggered by compression of clouds by radiation from massive stars, expanding bubbles in the interstellar medium, the collision of different molecular clouds, or the collision of galaxies (as in a starburst galaxy ). When a region reaches a sufficient density of matter to satisfy the criteria for Jeans instability , it begins to collapse under its own gravitational force. As
3321-434: A star of more than 9 solar masses expands to form first a blue supergiant and then a red supergiant . Particularly massive stars (exceeding 40 solar masses, like Alnilam , the central blue supergiant of Orion's Belt ) do not become red supergiants due to high mass loss. These may instead evolve to a Wolf–Rayet star , characterised by spectra dominated by emission lines of elements heavier than hydrogen, which have reached
3444-576: A test for laran . Kennard tells Jeff that his mother's name was Cleindori and his father was Terran; that after she was murdered, Jeff was put in the orphanage for his own safety, but he had been sent to Earth before his relations could reclaim him. Jeff meets Elorie of Arilinn and the other members of Arilinn Tower. Kennard explains the basics of Darkovan society and Tower functioning. The tower circle accepts Jeff, except for Auster, who remains hostile. Jeff remains for training. The tower performs some mining experiments, only to have their claims jumped by
3567-407: A white dwarf is no longer a plasma. Eventually, white dwarfs fade into black dwarfs over a very long period of time. In massive stars, fusion continues until the iron core has grown so large (more than 1.4 M ☉ ) that it can no longer support its own mass. This core will suddenly collapse as its electrons are driven into its protons, forming neutrons, neutrinos , and gamma rays in
3690-454: Is a planet stuck in a permanent ice age . Only one small equatorial strip of its single small continent is warm enough to support limited agriculture, fishing, and livestock. Similar in size to Earth, Darkover has a lower gravity due to its relative lack of metals; it also has a higher percentage of oxygen in the atmosphere. The planet's period of rotation is 28 hours. One Darkover year is roughly equal to fifteen Earth months. Darkover's weather
3813-598: Is a servant in the Alton townhouse in Thendara. Although the Kyrri can understand human speech, they do not speak themselves, and in Sharra's Exile Regis Hastur wonders how the message he gave one would be delivered. The Trailmen are described as social herbivores who dwell in arboreal communities and live in extended family clans. Unattached females form bands of ronin who wander the forests attacking travelers. These Trailmen-human cause
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3936-467: Is affected by two major forces: The planet is dominated by polar icecaps and glaciers that cover most of its surface. The habitable area, just a few degrees north of the equator, joins the northern polar icecap on its northern and eastern side. Glaciers and impassible mountains (The Wall Around the World) prevent travel outside of the habitable lands. Darkover's nominally temperate continental zone, which borders
4059-518: Is also frequently mentioned, the Ya-men, but Bradley leaves ambiguous the question of whether these creatures are sapient or not. The Catmen are the primary antagonists in The Spell Sword and feature in a number of the short stories. In The Spell Sword , Bradley describes them as carrying short, curved swords, capable of coordinating attacks against the humans, and able to use laran and starstones. The Catmen also featured prominently in several of
4182-420: Is cognate (shares the same root) with the following words: asterisk , asteroid , astral , constellation , Esther . Historically, stars have been important to civilizations throughout the world. They have been part of religious practices, divination rituals, mythology , used for celestial navigation and orientation, to mark the passage of seasons, and to define calendars. Early astronomers recognized
4305-679: Is far from finished. They go to the spaceport for safety. Jeff and Elorie marry, but are unable to leave Darkover for legal reasons. Elorie uses her Keeper's training to probe Jeff's memories of the death of his mother. He discovers that he is the son, not of Jefferson Kerwin, but of Lewis-Arnad Lanart-Alton. Kennard is his uncle. He also realises that Auster and Ragan are twins, the true children of Jefferson Kerwin, by Cassilda Lanart-Ridenow. The couple seeks help from Dyan Ardais, Elorie's half brother, to obtain an audience with Lord Hastur. Hastur admits that he should have done more to protect Cleindori, and her father, Damon Ridenow, saying he will not make
4428-409: Is primarily by convection , this ejected material is enriched with the fusion products dredged up from the core. Therefore, the planetary nebula is enriched with elements like carbon and oxygen. Ultimately, the planetary nebula disperses, enriching the general interstellar medium. Therefore, future generations of stars are made of the "star stuff" from past stars. During their helium-burning phase,
4551-450: Is that twins often have differing amounts of the family gifts. One twin usually has more of the gifts than does the other twin. Walter Breen cites Christopher Gibson for the observation that comyn is derived from the Gaelic word, comhionnan, meaning equal, and appears to refer to the communal origins of Darkover. A Comyn family frequently fosters a child from another Comyn family, at least for
4674-555: Is the International Astronomical Union (IAU). The International Astronomical Union maintains the Working Group on Star Names (WGSN) which catalogs and standardizes proper names for stars. A number of private companies sell names of stars which are not recognized by the IAU, professional astronomers, or the amateur astronomy community. The British Library calls this an unregulated commercial enterprise , and
4797-485: Is the Orion Nebula . Most stars form in groups of dozens to hundreds of thousands of stars. Massive stars in these groups may powerfully illuminate those clouds, ionizing the hydrogen, and creating H II regions . Such feedback effects, from star formation, may ultimately disrupt the cloud and prevent further star formation. All stars spend the majority of their existence as main sequence stars , fueled primarily by
4920-578: Is the Sun . Many other stars are visible to the naked eye at night ; their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms , and many of the brightest stars have proper names . Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations . The observable universe contains an estimated 10 to 10 stars. Only about 4,000 of these stars are visible to
5043-599: Is the Darkovan word for telepathic talent and the talents associated with it: telekinesis, precognition, a "sixth sense", empathy, teleportation, and others. It is the distinguishing feature of the people of Darkover. Although it appears mostly in Comyn, others may have it. It appears mostly in people who have red hair, and generally manifests itself at the time of puberty. Elorie Ardais, in The Bloody Sun , Chapter 7, says, "Everyone alive has some small degree of laran ". Damon Ridenow, in The Spell Sword , Chapter 6, reflects on
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5166-454: The Algol paradox , where the most-evolved star in a system is the least massive. The Bloody Sun The Bloody Sun is a science fantasy novel by American writer Marion Zimmer Bradley , part of her Darkover series. It was first published by Ace Books in 1964. The novel was substantially rewritten, expanded, and republished under the same title in 1979; Bradley's short story "To Keep
5289-698: The Comyn . In Star of Danger , the Chieri who aids Kennard Alton and Larry Montray, tells them that the Chieri share common ancestors with the Trailmen and the Kyrri , though not with the Terrans. The Chieri feature prominently in The World Wreckers , The Planet Savers , Star of Danger , and in the long-lived, half-human/half-Chieri characters, Robert Kadarin and Thyra Scott, who appear in The Heritage of Hastur and Sharra's Exile . The Cralmac are semi-intelligent beings, artificially bred by humans during
5412-685: The M87 and M100 galaxies of the Virgo Cluster , as well as luminous stars in some other relatively nearby galaxies. With the aid of gravitational lensing , a single star (named Icarus ) has been observed at 9 billion light-years away. The concept of a constellation was known to exist during the Babylonian period. Ancient sky watchers imagined that prominent arrangements of stars formed patterns, and they associated these with particular aspects of nature or their myths. Twelve of these formations lay along
5535-559: The New York City Department of Consumer and Worker Protection issued a violation against one such star-naming company for engaging in a deceptive trade practice. Although stellar parameters can be expressed in SI units or Gaussian units , it is often most convenient to express mass , luminosity , and radii in solar units, based on the characteristics of the Sun. In 2015, the IAU defined
5658-456: The angular momentum of the collapsing star and result in small patches of nebulosity known as Herbig–Haro objects . These jets, in combination with radiation from nearby massive stars, may help to drive away the surrounding cloud from which the star was formed. Early in their development, T Tauri stars follow the Hayashi track —they contract and decrease in luminosity while remaining at roughly
5781-632: The interstellar medium . These elements are then recycled into new stars. Astronomers can determine stellar properties—including mass, age, metallicity (chemical composition), variability , distance , and motion through space —by carrying out observations of a star's apparent brightness , spectrum , and changes in its position in the sky over time. Stars can form orbital systems with other astronomical objects, as in planetary systems and star systems with two or more stars. When two such stars orbit closely, their gravitational interaction can significantly impact their evolution. Stars can form part of
5904-449: The photographic magnitude . The development of the photoelectric photometer allowed precise measurements of magnitude at multiple wavelength intervals. In 1921 Albert A. Michelson made the first measurements of a stellar diameter using an interferometer on the Hooker telescope at Mount Wilson Observatory . Important theoretical work on the physical structure of stars occurred during
6027-575: The 11th century, the Persian polymath scholar Abu Rayhan Biruni described the Milky Way galaxy as a multitude of fragments having the properties of nebulous stars, and gave the latitudes of various stars during a lunar eclipse in 1019. According to Josep Puig, the Andalusian astronomer Ibn Bajjah proposed that the Milky Way was made up of many stars that almost touched one another and appeared to be
6150-472: The 2015 IAU nominal constants will remain the same SI values as they remain useful measures for quoting stellar parameters. Large lengths, such as the radius of a giant star or the semi-major axis of a binary star system, are often expressed in terms of the astronomical unit —approximately equal to the mean distance between the Earth and the Sun (150 million km or approximately 93 million miles). In 2012,
6273-562: The Ages of Chaos, from Trailmen altered with human DNA. They usually feature in the Darkovan novels as the servants of laranzu'in working in the towers, with the explanation that theirs is the only touch humans in the hyper-sensitive state of the matrix worker can bear. The Cralmac feature prominently in Patricia B. Cirone's Victory's Cost from Towers of Darkover . The Forge-Folk are not particularly well defined, though they are described as about
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#17328559994086396-533: The Aldarans. Austur believes it to be a Terran trick. They form a circle to identify the spy. It turns out to be Ragan, the weaselly man Jeff met his first night in the Trade City. Jeff claims vengeance, but the attempt to capture Ragan fails. Jeff decides to leave Arilinn, and Elorie, who has fallen in love with him, decides to go with him. The other members of the tower react with horror, indicating that Cleindori's work
6519-592: The Comyn for changes in policy or for assistance. In The Bloody Sun , Chapter 9, a group of Darkovans calling themselves the Pan-Darkovan Syndicate meets with Danvan Hastur and the members of the Arilinn Tower, and raises objections to the decision of the Comyn to limit trade and imports from the Terran Empire. Their spokesperson, Valdrin of Carthon, says they want some of the advantages that come with being
6642-413: The IAU defined the astronomical constant to be an exact length in meters: 149,597,870,700 m. Stars condense from regions of space of higher matter density, yet those regions are less dense than within a vacuum chamber . These regions—known as molecular clouds —consist mostly of hydrogen, with about 23 to 28 percent helium and a few percent heavier elements. One example of such a star-forming region
6765-413: The IAU defined the nominal solar mass parameter to be: The nominal solar mass parameter can be combined with the most recent (2014) CODATA estimate of the Newtonian constant of gravitation G to derive the solar mass to be approximately 1.9885 × 10 kg . Although the exact values for the luminosity, radius, mass parameter, and mass may vary slightly in the future due to observational uncertainties,
6888-583: The Oath" was included in this edition and all subsequent reprintings. The expanded rewrite retains the basic plot structure but is more closely connected to several other Darkover books, especially The Forbidden Tower . It also changes the identity of one of Kerwin's parents, although the later book Exile's Song uses his textually original parentage as background information. Damon Ridenow learns that Leonie Hastur, Keeper of Arilinn, has died. His daughter, Cleindori (a nickname, meaning "Golden Bell"; her real name
7011-622: The Priestesses of Avarra, a cloistered order that offered medical and other care to women, primarily abused women. Towards the end of Two to Conquer , Carlina di Asturien comes to believe that the two guilds need to work together for the benefit of all women on Darkover. Bradley acknowledged a Patricia Matthews fan story as the origin of the Sisterhood of the Sword, and described the Priesthood of Avarra as
7134-728: The Snows, a monastery founded by Father Valentine following a tragic event in Darkover Landfall . Storn is a castle (located on Storn Heights) and the Storn family was important in Stormqueen! and The Winds of Darkover . Shainsa is the chief of the Dry Towns and figures significantly in The Shattered Chain . The name Neskaya is derived from "New Skye", the first settlement, near the place where
7257-491: The Solar System, Isaac Newton suggested that the stars were equally distributed in every direction, an idea prompted by the theologian Richard Bentley . The Italian astronomer Geminiano Montanari recorded observing variations in luminosity of the star Algol in 1667. Edmond Halley published the first measurements of the proper motion of a pair of nearby "fixed" stars, demonstrating that they had changed positions since
7380-481: The Speakman map that illustrates this article. Thorsten Renk's attempt at mapping Darkover based on the descriptions of journeys provided in several of the books (starting with Darkover Landfall and ending with The Heritage of Hastur ) produced a third map that does not match the others. Renk says that Bradley appears to have a mental model when she writes, but not a map in the ordinary sense. Some cities or locations on
7503-439: The Sun enters the helium burning phase, it will expand to a maximum radius of roughly 1 astronomical unit (150 million kilometres), 250 times its present size, and lose 30% of its current mass. As the hydrogen-burning shell produces more helium, the core increases in mass and temperature. In a red giant of up to 2.25 M ☉ , the mass of the helium core becomes degenerate prior to helium fusion . Finally, when
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#17328559994087626-449: The Sun, and may have other planets , possibly even Earth-like, in orbit around them, an idea that had been suggested earlier by the ancient Greek philosophers , Democritus and Epicurus , and by medieval Islamic cosmologists such as Fakhr al-Din al-Razi . By the following century, the idea of the stars being the same as the Sun was reaching a consensus among astronomers. To explain why these stars exerted no net gravitational pull on
7749-467: The Terrans wonder how news travels so fast on Darkover. Towers are, in theory, independent of any caste discrimination or political influence. Each Tower should have a Keeper, a person to direct both Tower policy and the power of the laran users when they gather together in rapport to work. The Keeper of Arilinn is considered the second most-powerful person on Darkover, after the Hastur regent. One who goes to
7872-622: The Tower was destroyed, but its burnt rubble and a small chapel, the Rhu Fead , remain; Arilinn; Dalereuth; and Neskaya. Thendara is the location of the Comyn Castle and its Tower, which was destroyed in Exile's Song , as well as the main Terran spaceport and administrative offices. Another Terran spaceport is at Caer Donn. Nevarsin is a retreat and a center of learning administered by the monks of St. Valentine of
7995-537: The Ya-Men were — or are — like. I only know that they are very terrible indeed, with plumes and talons and shrill yelping cries ..." This is a conscious decision; she thinks that monsters should not be described in too much detail, lest they lose their horror. Comyn is the term used for aristocratic members of Darkover society who are gifted with the psychic abilities commonly called laran. Comyn women may be referred to as Comynara, especially by commoners. The Comyn are
8118-402: The assistance of Terran surveys), but the effort, at first successful, is abandoned. The most important mineral on Darkover is the matrix stone or starstone, a jewel that the first colonists discover in Darkover Landfall . It has a deep blue color, and large ones are rare. Its composition is not known by anyone, and in fact it is theorized by some that it is a form of life. This jewel provides
8241-495: The band of the ecliptic and these became the basis of astrology . Many of the more prominent individual stars were given names, particularly with Arabic or Latin designations. As well as certain constellations and the Sun itself, individual stars have their own myths . To the Ancient Greeks , some "stars", known as planets (Greek πλανήτης (planētēs), meaning "wanderer"), represented various important deities, from which
8364-496: The chemical composition of the stellar atmosphere to be determined. With the exception of rare events such as supernovae and supernova impostors , individual stars have primarily been observed in the Local Group , and especially in the visible part of the Milky Way (as demonstrated by the detailed star catalogues available for the Milky Way galaxy) and its satellites. Individual stars such as Cepheid variables have been observed in
8487-408: The cloud collapses, individual conglomerations of dense dust and gas form " Bok globules ". As a globule collapses and the density increases, the gravitational energy converts into heat and the temperature rises. When the protostellar cloud has approximately reached the stable condition of hydrostatic equilibrium , a protostar forms at the core. These pre-main-sequence stars are often surrounded by
8610-612: The cloud into multiple stars distributes some of that angular momentum. The primordial binaries transfer some angular momentum by gravitational interactions during close encounters with other stars in young stellar clusters. These interactions tend to split apart more widely separated (soft) binaries while causing hard binaries to become more tightly bound. This produces the separation of binaries into their two observed populations distributions. Stars spend about 90% of their lifetimes fusing hydrogen into helium in high-temperature-and-pressure reactions in their cores. Such stars are said to be on
8733-544: The conclusion of The Winds of Darkover , and are mentioned in several of the Sharra stories. The Kyrri are humanoid bipeds with grey or silver fur, simian faces and glowing green (or dark) eyes. Perhaps they are the result of genetic engineering during the Ages of Chaos , or they may be a native species from the pre-history of Darkover. In Sharra's Exile , Book Two, Chapter 5, Regis Hastur speculates that even tower workers do not know
8856-507: The continent's far western side is another mountain range called "The Hellers" and a high elevation cold desert plateau called "The Dry Towns". Multiple conflicting attempts to map Darkover exist, including one in The Heritage of Hastur (1975) which Bradley repudiated in a fan newsletter in 1978, saying, "The map in HH was fortunately inaccurate enough to be ignored". In any event, it does not match
8979-400: The core. The blown-off outer layers of dying stars include heavy elements, which may be recycled during the formation of new stars. These heavy elements allow the formation of rocky planets. The outflow from supernovae and the stellar wind of large stars play an important part in shaping the interstellar medium. Binary stars ' evolution may significantly differ from that of single stars of
9102-475: The cross-species transmission of a 48-year cyclic illness known as Trailmen's Fever, which is mild in Trailmen and often fatal in humans. The Chieri call the Trailmen a word that means "The Little Brothers Who Are Not Wise". The Trailmen feature prominently in the novels, The Planet Savers and Star of Danger , and in Diana L. Paxson's short story, The Place Between , from Snows of Darkover . The Ya-men are
9225-417: The direction of the Milky Way core . His son John Herschel repeated this study in the southern hemisphere and found a corresponding increase in the same direction. In addition to his other accomplishments, William Herschel is noted for his discovery that some stars do not merely lie along the same line of sight, but are physical companions that form binary star systems. The science of stellar spectroscopy
9348-405: The end of the star's life, fusion continues along a series of onion-layer shells within a massive star. Each shell fuses a different element, with the outermost shell fusing hydrogen; the next shell fusing helium, and so forth. The final stage occurs when a massive star begins producing iron. Since iron nuclei are more tightly bound than any heavier nuclei, any fusion beyond iron does not produce
9471-463: The expectation of male protection. In later books, "Free Amazons" is considered to be a misnomer and insulting or opprobrious, but the Renunciates themselves are tolerant of those who use "Free Amazons" out of ignorance. The origins of this guild during the Hundred Kingdoms era are described in Two to Conquer as the merger between the Sisterhood of the Sword, a military -mercenary guild, and
9594-517: The first decades of the twentieth century. In 1913, the Hertzsprung-Russell diagram was developed, propelling the astrophysical study of stars. Successful models were developed to explain the interiors of stars and stellar evolution. Cecilia Payne-Gaposchkin first proposed that stars were made primarily of hydrogen and helium in her 1925 PhD thesis. The spectra of stars were further understood through advances in quantum physics . This allowed
9717-437: The main sequence and are called dwarf stars. Starting at zero-age main sequence, the proportion of helium in a star's core will steadily increase, the rate of nuclear fusion at the core will slowly increase, as will the star's temperature and luminosity. The Sun, for example, is estimated to have increased in luminosity by about 40% since it reached the main sequence 4.6 billion ( 4.6 × 10 ) years ago. Every star generates
9840-677: The main sequence. The time a star spends on the main sequence depends primarily on the amount of fuel it has and the rate at which it fuses it. The Sun is expected to live 10 billion ( 10 ) years. Massive stars consume their fuel very rapidly and are short-lived. Low mass stars consume their fuel very slowly. Stars less massive than 0.25 M ☉ , called red dwarfs , are able to fuse nearly all of their mass while stars of about 1 M ☉ can only fuse about 10% of their mass. The combination of their slow fuel-consumption and relatively large usable fuel supply allows low mass stars to last about one trillion ( 10 × 10 ) years;
9963-412: The main sequence. Besides mass, the elements heavier than helium can play a significant role in the evolution of stars. Astronomers label all elements heavier than helium "metals", and call the chemical concentration of these elements in a star, its metallicity . A star's metallicity can influence the time the star takes to burn its fuel, and controls the formation of its magnetic fields, which affects
10086-819: The map are associated with the seven Domains: Hastur with the Hasturs; Armida with the Altons; Ardais with the Ardais; Serrais with the Ridenow; and Aldaran with the Aldarans. In Traitor's Sun , Chapter 3, the Domain of Elhalyn is described as stretching "from the west side of the Lake of Hali to the Sea of Dalereuth"; this is not on the map, nor is the Aillard Domain. Other names on the map are Towers: Hali, where
10209-458: The matrix stone is attuned will be able to open the box. Most persons with laran have a matrix stone that they carry in a small bag or pouch made of silk or leather, which are "insulators". Usually, the pouch is worn around the neck as a pendant. In general, the larger the stone, the more it can amplify the user's laran . Matrix stones can be used to power aircraft or make a person invisible ( The Bloody Sun ). Trained matrix mechanics can create
10332-458: The matrix workers at Ariliin agree to do a geological survey using their powers, to forestall a survey that otherwise would be done by the Terrans. They are to search for "tin, copper, silver, iron, tungsten" and for "fuels, for sulfur, hydrocarbons, chemicals". The purpose is to prevent Terrans and their "infernal machines" from spreading across Darkover. They succeed in locating mineral deposits and marking them on maps (ironically, maps created using
10455-456: The most extreme of 0.08 M ☉ will last for about 12 trillion years. Red dwarfs become hotter and more luminous as they accumulate helium. When they eventually run out of hydrogen, they contract into a white dwarf and decline in temperature. Since the lifespan of such stars is greater than the current age of the universe (13.8 billion years), no stars under about 0.85 M ☉ are expected to have moved off
10578-445: The motions of the planets and the inferred position of the Sun. The motion of the Sun against the background stars (and the horizon) was used to create calendars , which could be used to regulate agricultural practices. The Gregorian calendar , currently used nearly everywhere in the world, is a solar calendar based on the angle of the Earth's rotational axis relative to its local star, the Sun. The oldest accurately dated star chart
10701-442: The naked eye—all within the Milky Way galaxy . A star's life begins with the gravitational collapse of a gaseous nebula of material largely comprising hydrogen , helium, and trace heavier elements. Its total mass mainly determines its evolution and eventual fate. A star shines for most of its active life due to the thermonuclear fusion of hydrogen into helium in its core. This process releases energy that traverses
10824-479: The names of the planets Mercury , Venus , Mars , Jupiter and Saturn were taken. ( Uranus and Neptune were Greek and Roman gods , but neither planet was known in Antiquity because of their low brightness. Their names were assigned by later astronomers.) Circa 1600, the names of the constellations were used to name the stars in the corresponding regions of the sky. The German astronomer Johann Bayer created
10947-403: The nuclear fusion of hydrogen into helium within their cores. However, stars of different masses have markedly different properties at various stages of their development. The ultimate fate of more massive stars differs from that of less massive stars, as do their luminosities and the impact they have on their environment. Accordingly, astronomers often group stars by their mass: The formation of
11070-420: The oath is called her "oath-mother". Magdalene Lorne takes the name Margali n'ha Ysabet: Margali is a Darkovan version of her Terran name, Magdalene (she is also called Magda), and her mother's name was Elizabeth. Camilla, born Elorie Lindir, takes the name Camilla n'ha Kyria, because her mother was Kyria Aillard. Had she been legitimate or acknowledged as nedestro , her name might have been Elorie Hastur. Laran
11193-466: The odd fact that Andrew Carr, a Terran, has laran , and can telepathically be in touch with Callista when he and Callista's twin sister cannot: In the telepath caste, it was often the accident of possessing laran , the specific telepath Gift, which determined how close a relationship would come. Caste, family, social position, all these became irrelevant compared to that one compelling fact; one had, or one did not, that inborn power, and in consequence one
11316-452: The open water of the planet's ocean, is nevertheless subject to severe winter weather, and warm days in summer are rare. The temperate portion of the continent is dominated by evergreen forests that grow in the mountain foothills. These trees contain a flammable resin which contributes to frequent forest fires during the warmer months. Further, southwest from the forests are Darkover's highlands, plains, salt marshes and arable river valleys. On
11439-413: The original colonizing ship crashed. Darkover's metal resources are scarce. Gold and silver are known but not in any quantity, and the most valuable metal is copper. Wealthy women have "butterfly clasps" for their hair made of copper; poorer women make do with something fashioned of leather and wood. Iron is more common, but very valuable because it is used for swords and horseshoes. In City of Sorcery ,
11562-507: The origins of the Kyrri . Kyrri generate a bioelectric field and sometimes give painful but non-lethal electric shocks when excited or threatened. The Kyrri appear in The Bloody Sun , Star of Danger , and The Sword of Aldones , and also in Sharra's Exile , the replacement for the latter book. They are used primarily as servants in the Towers because they can pass through the barriers that non-telepathic humans cannot. In The Bloody Sun , one
11685-417: The outer convective envelope collapses and the star then moves to the horizontal branch. After a star has fused the helium of its core, it begins fusing helium along a shell surrounding the hot carbon core. The star then follows an evolutionary path called the asymptotic giant branch (AGB) that parallels the other described red-giant phase, but with a higher luminosity. The more massive AGB stars may undergo
11808-404: The outer shell of gas that it will push those layers away, forming a planetary nebula. If what remains after the outer atmosphere has been shed is less than roughly 1.4 M ☉ , it shrinks to a relatively tiny object about the size of Earth, known as a white dwarf . White dwarfs lack the mass for further gravitational compression to take place. The electron-degenerate matter inside
11931-640: The positions of the stars. They built the first large observatory research institutes, mainly to produce Zij star catalogues. Among these, the Book of Fixed Stars (964) was written by the Persian astronomer Abd al-Rahman al-Sufi , who observed a number of stars, star clusters (including the Omicron Velorum and Brocchi's Clusters ) and galaxies (including the Andromeda Galaxy ). According to A. Zahoor, in
12054-403: The problem of deriving an orbit of binary stars from telescope observations was made by Felix Savary in 1827. The twentieth century saw increasingly rapid advances in the scientific study of stars. The photograph became a valuable astronomical tool. Karl Schwarzschild discovered that the color of a star and, hence, its temperature, could be determined by comparing the visual magnitude against
12177-497: The proper motion of the star Sirius and inferred a hidden companion. Edward Pickering discovered the first spectroscopic binary in 1899 when he observed the periodic splitting of the spectral lines of the star Mizar in a 104-day period. Detailed observations of many binary star systems were collected by astronomers such as Friedrich Georg Wilhelm von Struve and S. W. Burnham , allowing the masses of stars to be determined from computation of orbital elements . The first solution to
12300-438: The roof with materials and tools. The highest degree is Keeper, but generally women are trained for this arduous position from a young age. Not many young women want to undergo this. A Keeper is the center of a group of laran workers, who accepts the energy ("energons") that they generate and directs it. Star A star is a luminous spheroid of plasma held together by self-gravity . The nearest star to Earth
12423-485: The same height and build as the Trailmen. Walter Breen's The Darkover Concordance describes them as a cross between humans and non-humans, who speak an ancient variant of the Hellers dialect. They are Darkover's primary miners and metalworkers. The Forge Folk worship the Sharra matrix , and appear to be the only creatures on Darkover capable of handling Sharra without causing catastrophe. The Forge-Folk feature prominently in
12546-461: The same mass. For example, when any star expands to become a red giant, it may overflow its Roche lobe , the surrounding region where material is gravitationally bound to it; if stars in a binary system are close enough, some of that material may overflow to the other star, yielding phenomena including contact binaries , common-envelope binaries, cataclysmic variables , blue stragglers , and type Ia supernovae . Mass transfer leads to cases such as
12669-405: The same mistake with Elorie. He listens to her story. Unable to contact Arilinn to warn them about the threat posed by the unsuspected link between Auster and Ragan, Jeff and Elorie ride to Arilinn. They are able to exclude Ragan from the circle and complete their task. Elorie is injured, but survives. Jeff tells the circle that the experience proves Cleindori was right – that matrix mechanics are
12792-451: The same temperature. Less massive T Tauri stars follow this track to the main sequence, while more massive stars turn onto the Henyey track . Most stars are observed to be members of binary star systems, and the properties of those binaries are the result of the conditions in which they formed. A gas cloud must lose its angular momentum in order to collapse and form a star. The fragmentation of
12915-449: The seven Domains. Each Comyn family controls part of Darkover's landmass, known as a Domain, but strategic inter-marriage and feudal land issues result in fluctuating domain borders. Each Comyn family has a gift — a family-specific laran power, though in reality, not every member of the family has the family gift. Also, a member of a family may have another family's gift, in whole or in part. The gifts may skip generations. Of particular note
13038-581: The short stories, including David Heydt's I'm a Big Cat Now from Towers of Darkover ; Linda Frankel and Paula Crunk's Blood Hunt from The Other Side of the Mirror ; and Judith Sampson's To Serve Kihar from Domains of Darkover . The Chieri are a race of six-fingered, tall, telepathic humanoids who have no permanent gender. Extremely long-lived, with life-spans reaching into the tens of thousands of years, they are described as gray or golden-eyed and with long, silvery-white hair. They will change sexes as
13161-431: The situation warrants for mating purposes. The World Wreckers describes the Chieri as the last, dying remnants of a space-traveling people whose abilities have dwindled with their fertility and ambition. Chieri and humans are similar biologically and are able to interbreed. These hybrids exhibit some of the Chieri characteristics of coloring and physiology. They also have psychic gifts, and their descendants become
13284-445: The star's interior and radiates into outer space . At the end of a star's lifetime as a fusor , its core becomes a stellar remnant : a white dwarf , a neutron star , or—if it is sufficiently massive—a black hole . Stellar nucleosynthesis in stars or their remnants creates almost all naturally occurring chemical elements heavier than lithium . Stellar mass loss or supernova explosions return chemically enriched material to
13407-500: The star's outer layers, leaving a remnant such as the Crab Nebula. The core is compressed into a neutron star , which sometimes manifests itself as a pulsar or X-ray burster . In the case of the largest stars, the remnant is a black hole greater than 4 M ☉ . In a neutron star the matter is in a state known as neutron-degenerate matter , with a more exotic form of degenerate matter, QCD matter , possibly present in
13530-400: The strength of its stellar wind. Older, population II stars have substantially less metallicity than the younger, population I stars due to the composition of the molecular clouds from which they formed. Over time, such clouds become increasingly enriched in heavier elements as older stars die and shed portions of their atmospheres . As stars of at least 0.4 M ☉ exhaust
13653-485: The supply of hydrogen at their core, they start to fuse hydrogen in a shell surrounding the helium core. The outer layers of the star expand and cool greatly as they transition into a red giant . In some cases, they will fuse heavier elements at the core or in shells around the core. As the stars expand, they throw part of their mass, enriched with those heavier elements, into the interstellar environment, to be recycled later as new stars. In about 5 billion years, when
13776-468: The surface due to strong convection and intense mass loss, or from stripping of the outer layers. When helium is exhausted at the core of a massive star, the core contracts and the temperature and pressure rises enough to fuse carbon (see Carbon-burning process ). This process continues, with the successive stages being fueled by neon (see neon-burning process ), oxygen (see oxygen-burning process ), and silicon (see silicon-burning process ). Near
13899-611: The surviving laran-gifted families of Darkover who are ruling at the time of recontact with the Terran Empire. It is suggested in Darkover Landfall that they are the descendants of human-chieri pairings, who have learned to use native matrix stones to focus their laran powers. The Comyn, however, have their own mythology, recited in the Ballad of Hastur and Cassilda : they are the descendants of Hastur, son of Aldones, Lord of Light, who fell to earth, fell in love with Cassilda, and (perhaps) became mortal. Cassilda bore Hastur seven sons who founded
14022-455: The temperature increases sufficiently, core helium fusion begins explosively in what is called a helium flash , and the star rapidly shrinks in radius, increases its surface temperature, and moves to the horizontal branch of the HR diagram. For more massive stars, helium core fusion starts before the core becomes degenerate, and the star spends some time in the red clump , slowly burning helium, before
14145-400: The time of the ancient Greek astronomers Ptolemy and Hipparchus. William Herschel was the first astronomer to attempt to determine the distribution of stars in the sky. During the 1780s, he established a series of gauges in 600 directions and counted the stars observed along each line of sight. From this, he deduced that the number of stars steadily increased toward one side of the sky, in
14268-691: The trainee is proficient at this, he is qualified to "monitor" other laran workers to ensure that they are not in danger when working, and takes the Monitor's Oath, with the approval of the members of the Tower. A person who is deemed morally or otherwise unfit to work with laran will not be allowed to take the oath and will be expelled from the tower without any more training. This apparently happened to Dyan Ardais. A matrix Mechanic learns to manipulate matter and energy using his laran and matrix stone, and to make and use tools that focus and augment laran. In The Bloody Sun Jeff Kerwin, just beginning his training as
14391-477: Was Dorilys Aillard, daughter of Jaelle n'ha Melora) arrived with Kennard Alton in tow. She has decided to go to Arilinn to train as their Keeper. Ridenow objects, but can't talk her out of her decision. About forty years later, Jefferson Andrew Kerwin, age 29, arrives on Darkover. He knows that he was born there, and spent his first ten years in the Spaceman's Orphanage. In the Trade City, he meets Ragan, who identifies
14514-435: Was developed by Annie J. Cannon during the early 1900s. The first direct measurement of the distance to a star ( 61 Cygni at 11.4 light-years ) was made in 1838 by Friedrich Bessel using the parallax technique. Parallax measurements demonstrated the vast separation of the stars in the heavens. Observation of double stars gained increasing importance during the 19th century. In 1834, Friedrich Bessel observed changes in
14637-419: Was pioneered by Joseph von Fraunhofer and Angelo Secchi . By comparing the spectra of stars such as Sirius to the Sun, they found differences in the strength and number of their absorption lines —the dark lines in stellar spectra caused by the atmosphere's absorption of specific frequencies. In 1865, Secchi began classifying stars into spectral types . The modern version of the stellar classification scheme
14760-436: Was stranger or kinfolk. By that criterion alone, the most important one on Darkover, Andrew Carr was one of them, and the fact that he was an Earthman was a small random fact without any real importance. Being telepathically connected to another is called being "in rapport". Elizabeth Mackintosh, a character in the novel Rediscovery , suggests the Darkovan language appears to be derived from old Terran languages. She proposes
14883-586: Was the SN 1006 supernova, which was observed in 1006 and written about by the Egyptian astronomer Ali ibn Ridwan and several Chinese astronomers. The SN 1054 supernova, which gave birth to the Crab Nebula , was also observed by Chinese and Islamic astronomers. Medieval Islamic astronomers gave Arabic names to many stars that are still used today and they invented numerous astronomical instruments that could compute
15006-603: Was the result of ancient Egyptian astronomy in 1534 BC. The earliest known star catalogues were compiled by the ancient Babylonian astronomers of Mesopotamia in the late 2nd millennium BC, during the Kassite Period ( c. 1531 BC – c. 1155 BC ). The first star catalogue in Greek astronomy was created by Aristillus in approximately 300 BC, with the help of Timocharis . The star catalog of Hipparchus (2nd century BC) included 1,020 stars, and
15129-480: Was used to assemble Ptolemy 's star catalogue. Hipparchus is known for the discovery of the first recorded nova (new star). Many of the constellations and star names in use today derive from Greek astronomy. Despite the apparent immutability of the heavens, Chinese astronomers were aware that new stars could appear. In 185 AD, they were the first to observe and write about a supernova , now known as SN 185 . The brightest stellar event in recorded history
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