Nidor is a fictional planet, the setting for two science fiction books of the 1950s, The Shrouded Planet and The Dawning Light, written by Robert Silverberg and Randall Garrett. They were originally published in serial form in Astounding Science Fiction, under the pseudonym Robert Randall.
Nidor's star is a massive, blue-white giant, which it orbits at a great distance, completing a revolution in about three thousand years. Even so, the planet is warmer than Earth, with a mean temperature in excess of 40 degrees Celsius. The planet is mostly covered by ocean, with a single continent inhabited by humanoids, the Nidorians, who have an agrarian culture somewhat like late medieval or early Renaissance Europe.
The planet was invented to meet certain requirements of the authors, notably that it be permanently enveloped in clouds so the Nidorians would have no concept of an external universe. They took no account of what is now known about giant stars, which is that their lives are too short—less than 100 million years—for planets to form, let alone for intelligent humanoids to evolve. The author Poul Anderson, in a later story, imagined a planet circling such as star but originating around another star, from which it was captured by the giant star, sidestepping the stellar lifetime issue.
A few basic calculations, assuming that stellar luminosity increases as the fourth power of the mass, while for a given orbital period the orbit radius increases as the cube root of the star's mass, indicates that Nidor probably orbits a star of about 16 solar masses, at a distance of about 500 AU, if the amount of heat and light it receives is about the same as Earth's, or perhaps 5% more.
There is no Nidorian solar "year" analogous to an Earth solar year. The year is instead an artificial construct based on 16 periods of 16 days. 16 years is a Cycle. The storyline begins in the 240th Cycle of Nidor.
As mentioned above, Nidor has one continent, with low mountains and many rivers, as befits a rainy climate. Some distance from the continent are the outlying Bronze Islands, named for the copper and zinc mined there. These islands were carefully placed to ensure a rich seafaring tradition, ensuring that travel by river and sea is an important part of the culture. They also provide an opportunity to introduce culturally eccentric individuals to the otherwise homogeneous Nidorian social matrix.
For the purposes of the storyline, the planet needed to be as Earth-like as possible. Therefore the atmosphere is breathable by humans, containing oxygen in the right amount along with another inert gas, probably nitrogen, saturated with water vapor, about 2% by volume, and with no toxic components. Given the high temperature and the preponderance of ocean, there would be no icecaps, nor any natural ice or snow. There is consistent rainfall, mostly at night. The rainfall brings much erosion, ensuring that the single landmass has no mountains higher than 1000 metres.
Plant and animal life is similar to that of Earth, at least on land. There are tree- and shrub-like plants, and the ubiquitous peych-bean which is the staple of life, providing food, textiles and animal fodder. There are insect-like creatures, particularly the hugl, which is a major pest that can form plagues like locusts. There are domesticated quadrupedal animals such as the deest, different breeds of which are used as draft animals or racing mounts, much like the horse. The deest walks on three toes instead of a single hoof like a horse.
Sea life is not well-described. There is mention of carnivorous flying sea-lizards.
The Nidorians 
Nidorians are very human-like, except for the distribution of hair, which is short, fine, and covers the whole body. They are similar in size to humans and there are both male and female Nidorians, with social and biological roles exactly analogous to those of humans. Clothing tends to be light, if worn at all, consisting of shorts and a singlet or vest. Clothing is a mark of social role and standing rather than a way of keeping warm and dry.
Society and religion 
There is no separation between religion and society on Nidor. The Nidorians see themselves as the Chosen people, the descendants of those who survived the Great Cataclysm which wiped out all others. They were led to safety by a prophet, and given Law and Scripture to follow. These dictate all aspects of life, maintaining a stable tradition for thousands of years, or hundreds of Cycles. Nidorians believe that departing from the Way of the Ancestors will bring about another Cataclysm as punishment.
The society is a hierarchical, patriarchal, clan-based theocracy. There is a Holy City, Gelusar, containing the Great Temple. The deity is the Great Light, i.e. the Sun, which is visible through the perpetual clouds as a glow. A Lesser Light, evidently a moon, shines, or rather glows, at night. The light from the Sun is powerful enough, when focussed by a lens, to set alight a mound of herbs used in a Temple ceremony.
The highest authority is the High Council of Elders, with 16 members, one from each clan. Succession to and within the High Council is rigidly based on seniority. Respect for elders is so entrenched in society that even young people may be addressed as Aged One as a term of respect. The Elders are called Grandfather as a title. There are formulas for greeting someone, saying goodbye, and apologizing to an elder (elders never have to apologize to younger Nidorians). A farewell might be "May you walk in the Way of our Ancestors" with the ritual reply "May the Great Light illumine your mind as he does the world".
The most important item in Nidorian life, after religion, is the cultivation of the staple crop, the peych-bean which provides food, textiles, fuel, fermented drink, and animal fodder. Said cultivation is naturally governed by Law, Scripture and tradition. So successful is this system that famines and gluts are rare, and prices have been stable as far as anyone can remember.
Law and order 
Order is kept by Peacemen, lightly armed police who mostly have little to do. The bank which is robbed in The Dawning Light has a single guard who is mostly a figure of fun, overweight and waddling around. The main crime is blasphemy, often punished by mobs armed with stones. Other criminals, once apprehended, are simply restrained by burly Peacemen and put up for trial by the local Elders.
As order breaks down in the stories, tools are used as weapons. Later there are basic firearms using cartridges and gunpowder.
Public works 
Each major function of society has an official in charge, known as the Uncle. Thus there is the Uncle of Public Works, the Uncle of Public Peace etc. The Uncle has the right to recruit any able-bodied man to help with a task, as in the story of Kiv pGanz Brajjyd, who hears of work on the bridge he must cross to get to Gelusar. He realizes that he will be recruited if he goes that way, delaying his arrival in the city.
The calendar 
The Nidorian calendar consists of 16-day periods, called 1st, 2nd, etc., up to 16 in the Nidorian year. Thus one year is 256 days. There is no solar year. There are many days of feasting and commemoration with attendant religious obligations. Dates may be quoted relative to a well-known feast.
16 Nidorian years, each named for a clan, constitutes a Cycle. The first year in each Cycle is Yorgen, and the first day of the first period of Yorgen is Cycle Day, in commemoration of the Great Cataclysm and the salvation of the 16 families led by Bel-rogas Yorgen.
The final component of a date is the Cycle number, which stands at 240 and higher in the stories. Thus the stories begin after 239 Cycles, or 3824 Nidorian years from the beginning of the calendar.
Place names 
Such place names as are mentioned follow a logical scheme. Apart from the city of Holy Gelusar, the names are geographically derived, mostly from the names of rivers. The suffix -cor means the mouth of a river, from which are derived the names of the large port cities Tammulcor and Vashcor. Gelusar is upriver from Tammulcor. The river Vash flows through the provinces named Pelvash and Thryvash.
There is brisk trade in peych, its products and the materiel needed to cultivate it. There is a single currency, the weight, based on a standard amount of the metal cobalt. Coins made of cobalt are used, but there is also paper scrip backed by reserves of cobalt. The currency is carefully controlled by the High Council of Elders, who replace lost coinage and issue notes only according to the reserves of metal.
A "man-weight" is about 80,000 weights, making a weight roughly equivalent to 1 gram, assuming 80 kg individuals. In The Dawning Light 8 million weights are stolen from a bank, amounting to 100 manweights of cobalt. For comparison, a US nickel coin is exactly 5 g of copper-nickel alloy. Thus a 1-weight coin would be small indeed.
There are bronze coins denominated in pieces, with 12 pieces being 1 weight. All coins have a triangular hole in the middle and are carried threaded on wire or fiber. The authors even describe the inscriptions on the coins: the price side has the number showing the value, and the prayers side has an inscribed saying. Nidorians, like Earthmen, toss a coin from time to time for a bet, or to break a deadlock. Instead of "Heads or tails?" the Nidorian call is "Price or prayers?" The triangular hole in the coins symbolises the opening in the ceiling of the Great Temple through which the Great Light shines.
Clan organization 
Nidorian tradition tells that 16 families, led by a Bel-rogas Yorgen, escaped the Cataclysm to reach Nidor. The 16 families became the 16 clans. Clan names include Yorgen, Brajjyd, Sesom and Gormek. An individual will identify him- or herself with a given name, a patronymic, and a clan name. Married Nidorian women can add a spousal name. Spousal names and patronymics are formed by prefixing the husband or father's given name. The spousal name iKiv indicates "wife of Kiv" while the patronymics peKiv and geKiv indicate "son of Kiv" and "daughter of Kiv" respectively.
Nidorians practice marriage and tend to live in nuclear families. According to custom, marriage is forbidden between two members of the same clan. However since the outlying Bronze Islands are populated entirely by the clan Gormek, it is difficult to see how the custom can hold there. Bronze Islanders are either sailors or miners, and both are regarded as unreliable by the rest of society. Childbearing outside marriage, or any other violation of the strict moral codes, will likely result in death by stoning.
Professions are passed down within a family, with other children being encouraged to join the priesthood, or become physicians. There are no law or politics professions, except for the priesthood itself.
Clan names 
In approximate order of importance to the storyline, the names are:
- (two others not named)