A helictite is a speleothem found in limestone caves that changes its axis from the vertical at one or more stages during its growth. They have a curving or angular form that looks as if they were grown in zero gravity and they are most likely the result of capillary forces acting on tiny water droplets, a force often strong enough at this scale to defy gravity. They are formed by biologically-mediated processes, rather than abiotic processes as scientists previoulsy thought, Helictites are, the most delicate of cave formations. They are usually made of calcite and aragonite. Forms of helictites have been described in several types, ribbon helictites, rods, hands, curly-fries and they can be easily crushed or broken by the slightest touch. Because of this, helictites are rarely seen within arms reach in tourist caves, timpanogos Cave National Monument in Utah has one of the largest collections of these formations in the world. The large numbers are in the Jenolan Caves in Australia, a remarkable suite of helictites is occurring in Asperge Cave in France.
The growth of helictites is still quite enigmatic, to this day there has been no satisfactory explanation for how they are formed. Currently, formation by capillary forces is the most likely theory, the most likely theory explains helictites as a result of capillary forces. If the helictite has a thin central tube where the water flows like it does in straws. This theory was inspired by some hollow helictites, the majority of helictites are definitely not hollow. Despite this, droplets can be drawn to the tips of existing structures and this can lead to the wandering and curling structures seen in many helictites. Another theory names the wind in the cave as main reason for the strange look, drops hanging on a stalactite are blown to one side, so the dripstone grows in that direction. If the wind changes, the direction of growth changes too, however this theory is very problematic, because wind directions change very often. The wind in caves depends on air pressure changes outside, which in turn depend on the weather, wind caves are known to experience these windy conditions.
The wind direction changes as often as the conditions outside change. A second problem with this theory is that caves with helictites have no natural entrance where wind could enter. A recent theory which is supported by observation is that a prokaryotic bacterial film provides nucleation site for mineralization process, a helictite starts its growth as a tiny stalactite
A cave pearl is a small, usually spherical, speleothem found in limestone caves. Cave pearls are formed by a concretion of calcium salts that form concentric layers around a nucleus, exposure to moving water polishes the surface of cave pearls, making them glossy, if exposed to the air, cave pearls can degrade and appear rough. A cave pearl is composed primarily of calcite, Cave pearls are generally not considered to be a type of oolite. Other minerals found in quantities in cave pearls include quartz, iron, aluminum. Cave pearls form when water dripping into a cave loses carbon dioxide, a cave pearl forms when the water is moving too vigorously to form a stalagmite. A nucleus of matter becomes coated with calcite, and the current provides a rotation to the nucleus in such a way that it is coated evenly. In this manner, concentric layers build up time, in much the same way that a biological pearl forms within a mollusc. There may be microbial action involved in the formation of cave pearls, the existence of an actual pool may not be necessary for cave pearls to form, as long as the deposit is kept wet and agitated by water dripping or trickling through.
If the cave pearl sinks to the bottom of a pool, or is otherwise in contact with moving water. Although the motion of the water often keeps cave pearls from adhering, a cave pearl forms around a nucleus of matter. The nucleus of a pearl is typically very small, such as a grain of sand. Some nuclei are made of matter, whereas others are made of calcified clay or limestone. Cave pearls are usually spherical, but can have other shapes, the reason cave pearls tend to be round is not their rotation, but rather that their growth is steady and uniform. Because a spherical shape allows the greatest amount of deposition for the smallest surface area, sometimes several cave pearls stick together to form a shape that resembles a bunch of grapes. In addition to the spherical shape, cave pearls can be cylindrical, cubical, discoid. Most cave pearls are smaller than 1 cm wide, large cave pearls grow as big as 20 cm in diameter. The worlds largest cave, Son Doong Cave in Vietnam, has cave pearls the size of baseballs, Cave pearls are relatively common in caves, but are typically present in low abundance.
The mechanism for the formation of this vast quantity of pearls has not been determined, the Rookery, in Carlsbad Caverns, New Mexico, has so many cave pearls that they were at one time handed out to visitors as souvenirs
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is widely mined and is used as a fertilizer, and as the constituent in many forms of plaster, blackboard chalk. Mohs scale of hardness, based on scratch Hardness comparison. It forms as a mineral and as a hydration product of anhydrite. The word gypsum is derived from the Greek word γύψος, because the quarries of the Montmartre district of Paris have long furnished burnt gypsum used for various purposes, this dehydrated gypsum became known as plaster of Paris. Upon addition of water, after a few tens of minutes plaster of Paris becomes regular gypsum again, causing the material to harden or set in ways that are useful for casting, Gypsum was known in Old English as spærstān, spear stone, referring to its crystalline projections. Gypsum may act as a source of sulfur for plant growth, which was discovered by J. M. Mayer, american farmers were so anxious to acquire it that a lively smuggling trade with Nova Scotia evolved, resulting in the so-called Plaster War of 1820.
In the 19th century, it was known as lime sulfate or sulfate of lime. Gypsum is moderately water-soluble and, in contrast to most other salts, it exhibits retrograde solubility, when gypsum is heated in air it loses water and converts first to calcium sulfate hemihydrate, and, if heated further, to anhydrous calcium sulfate. As for anhydrite, its solubility in saline solutions and in brines is dependent on NaCl concentration. Gypsum crystals are found to contain water and hydrogen bonding. Gypsum occurs in nature as flattened and often twinned crystals, and transparent, selenite contains no significant selenium, both substances were named for the ancient Greek word for the Moon. Selenite may occur in a silky, fibrous form, in case it is commonly called satin spar. Finally, it may be granular or quite compact, in hand-sized samples, it can be anywhere from transparent to opaque. A very fine-grained white or lightly tinted variety of gypsum, called alabaster, is prized for ornamental work of various sorts, in arid areas, gypsum can occur in a flower-like form, typically opaque, with embedded sand grains called desert rose.
It forms some of the largest crystals found in nature, up to 12 m long, Gypsum is a common mineral, with thick and extensive evaporite beds in association with sedimentary rocks. Deposits are known to occur in strata from as far back as the Archaean eon, Gypsum is deposited from lake and sea water, as well as in hot springs, from volcanic vapors, and sulfate solutions in veins. Hydrothermal anhydrite in veins is commonly hydrated to gypsum by groundwater in near-surface exposures and it is often associated with the minerals halite and sulfur
The term public domain has two senses of meaning. Anything published is out in the domain in the sense that it is available to the public. Once published and information in books is in the public domain, in the sense of intellectual property, works in the public domain are those whose exclusive intellectual property rights have expired, have been forfeited, or are inapplicable. Examples for works not covered by copyright which are therefore in the domain, are the formulae of Newtonian physics, cooking recipes. Examples for works actively dedicated into public domain by their authors are reference implementations of algorithms, NIHs ImageJ. The term is not normally applied to situations where the creator of a work retains residual rights, as rights are country-based and vary, a work may be subject to rights in one country and be in the public domain in another. Some rights depend on registrations on a basis, and the absence of registration in a particular country, if required. Although the term public domain did not come into use until the mid-18th century, the Romans had a large proprietary rights system where they defined many things that cannot be privately owned as res nullius, res communes, res publicae and res universitatis.
The term res nullius was defined as not yet appropriated. The term res communes was defined as things that could be enjoyed by mankind, such as air, sunlight. The term res publicae referred to things that were shared by all citizens, when the first early copyright law was first established in Britain with the Statute of Anne in 1710, public domain did not appear. However, similar concepts were developed by British and French jurists in the eighteenth century, instead of public domain they used terms such as publici juris or propriété publique to describe works that were not covered by copyright law. The phrase fall in the domain can be traced to mid-nineteenth century France to describe the end of copyright term. In this historical context Paul Torremans describes copyright as a coral reef of private right jutting up from the ocean of the public domain. Because copyright law is different from country to country, Pamela Samuelson has described the public domain as being different sizes at different times in different countries.
According to James Boyle this definition underlines common usage of the public domain and equates the public domain to public property. However, the usage of the public domain can be more granular. Such a definition regards work in copyright as private property subject to fair use rights, the materials that compose our cultural heritage must be free for all living to use no less than matter necessary for biological survival
Colossal Cave Adventure
Colossal Cave Adventure is a text adventure game, developed originally in 1976, by Will Crowther for the PDP-10 mainframe. The game was expanded upon in 1977, with help from Don Woods, in the game, the player controls a character through simple text commands to explore a cave rumored to be filled with wealth. Players earn predetermined points for acquiring treasure and escaping the cave alive, the concept bore out from Crowthers background as a caving enthusiast, with the games cave structured loosely around the Mammoth Cave system in Kentucky. Colossal Cave Adventure is the first known work of fiction and. Colossal Cave Adventure contributed towards the playing and roguelike genres. Adventure has the players explore a mysterious cave that is rumored to be filled with treasure. YOU ARE STANDING AT THE END OF A ROAD BEFORE A SMALL BRICK BUILDING, a SMALL STREAM FLOWS OUT OF THE BUILDING AND DOWN A GULLY. Go south YOU ARE IN A VALLEY IN THE FOREST BESIDE A STREAM TUMBLING ALONG A ROCKY BED, programs replies are typically in a humorous, conversational tone, much as a dungeon master would use in leading players in a tabletop role-playing game. A notable example is when the player dies after falling into a pit, go west YOU FELL INTO A PIT AND BROKE EVERY BONE IN YOUR BODY. YOU DONT EXPECT ME TO DO A DECENT REINCARNATION WITHOUT ANY ORANGE SMOKE, DO YOU. yes OKAY, IF YOURE SO SMART, certain actions may cause the death of the character, requiring the player to start again.
The game has a point system, whereby completing certain goals earns a number of predetermined points, the ultimate goal is to earn the maximum amount of points, which partially correlates to finding all the treasures in the game and safely leaving the cave. Will Crowther was a programmer at Bolt, Beranek & Newman and his wife Pat were experienced cavers, having previously helped to create vector map surveys of the Mammoth Cave in Kentucky in the early 1970s for the Cave Research Foundation. In addition, Crowther enjoyed playing the tabletop role-playing game Dungeons & Dragons with a group which included Eric S. Roberts and Dave Lebling. Developed over 1975 and 1976, Crowthers original game consisted of about 700 lines of FORTRAN code, with about another 700 lines of data, the data included text for 78 map locations,193 vocabulary words, travel tables, and miscellaneous messages. On the PDP-10, the loads and executes with all its game data in memory. It required about 60k words of memory, which was a significant amount for PDP-10/KA systems running with only 128k words.
Crowthers original version did not include any scorekeeping, during that time, others had found the game and it was distributed widely across the network, which had surprised Crowther on his return. Though titled in-game as Colossal Cave Adventure, its executable file was simply named ADVENT, one of those that had discovered the game was Don Woods, a graduate student at Stanford University in 1976
Don Woods (programmer)
Don Woods is an American perennial hacker and computer programmer. He is probably best known for his role in the development of the Colossal Cave Adventure game, Woods teamed with James M. Lyon while both were attending Princeton in 1972 to produce the unprecedented, excursive INTERCAL programming language. Later, he worked at the Stanford AI lab, where among other things he became the SAIL contact for, and a contributor to, the Jargon File. He co-authored The Hackers Dictionary with Mark Crispin, Raphael Finkel, after contacting the original author by the means of sending an e-mail to crowther@sitename, where sitename was every host listed on ARPANET, he heard back from William Crowther shortly afterward. Given the go-ahead, Woods proceeded to add enhancements to the Adventure game and it became very popular, especially with users of the PDP-10. Woods stocked the Kentucky cave that Crowther had written with new items, creatures. Crowthers game, which featured few supernatural elements, was transformed into a loose fantasy world featuring elements from role playing games.
Woods can thus, in a sense, be considered one of the progenitors of the genre of computer adventure games. By 1977 tapes of the game were common on the Digital user group DECUS, Don Woods web page Interview with Woods regarding Adventure Computerworld Interview with Don Woods on INTERCAL
Kentucky, officially the Commonwealth of Kentucky, is a state located in the east south-central region of the United States. Kentucky is one of four U. S. states constituted as a commonwealth, originally a part of Virginia, in 1792 Kentucky became the 15th state to join the Union. Kentucky is the 37th most extensive and the 26th most populous of the 50 United States, Kentucky is known as the Bluegrass State, a nickname based on the bluegrass found in many of its pastures due to the fertile soil. One of the regions in Kentucky is the Bluegrass Region in central Kentucky. In 1776, the counties of Virginia beyond the Appalachian Mountains became known as Kentucky County, the precise etymology of the name is uncertain, but likely based on an Iroquoian name meaning the meadow or the prairie. Kentucky is situated in the Upland South, a significant portion of eastern Kentucky is part of Appalachia. Kentucky borders seven states, from the Midwest and the Southeast, West Virginia lies to the east, Virginia to the southeast, Tennessee to the south, Missouri to the west and Indiana to the northwest, and Ohio to the north and northeast.
Only Missouri and Tennessee, both of which border eight states, touch more, Kentuckys northern border is formed by the Ohio River and its western border by the Mississippi River. The official state borders are based on the courses of the rivers as they existed when Kentucky became a state in 1792, for instance, northbound travelers on U. S.41 from Henderson, after crossing the Ohio River, will be in Kentucky for about two miles. Ellis Park, a racetrack, is located in this small piece of Kentucky. Waterworks Road is part of the land border between Indiana and Kentucky. Kentucky has a part known as Kentucky Bend, at the far west corner of the state. It exists as an exclave surrounded completely by Missouri and Tennessee, Road access to this small part of Kentucky on the Mississippi River requires a trip through Tennessee. The epicenter of the powerful 1811–12 New Madrid earthquakes was near this area, much of the outer Bluegrass is in the Eden Shale Hills area, made up of short and very narrow hills.
The Jackson Purchase and western Pennyrile are home to several bald cypress/tupelo swamps, located within the southeastern interior portion of North America, Kentucky has a climate that can best be described as a humid subtropical climate. Temperatures in Kentucky usually range from daytime summer highs of 87 °F to the low of 23 °F. The average precipitation is 46 inches a year, Kentucky experiences four distinct seasons, with substantial variations in the severity of summer and winter. The highest recorded temperature was 114 °F at Greensburg on July 28,1930 while the lowest recorded temperature was −37 °F at Shelbyville on January 19,1994, due to its location, Kentucky has a moderate humid subtropical climate, with abundant rainfall
Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power.
The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations.
In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
Fossils are the preserved remains or traces of animals and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record. The study of fossils across geological time, how they were formed, such a preserved specimen is called a fossil if it is older than some minimum age, most often the arbitrary date of 10,000 years. The observation that fossils were associated with certain rock strata led early geologists to recognize a geological timescale in the 19th century. The development of dating techniques in the early 20th century allowed geologists to determine the numerical or absolute age of the various strata. Like extant organisms, fossils vary in size from microscopic, even single bacterial cells one micrometer in diameter, to gigantic, such as dinosaurs, Fossils may consist of the marks left behind by the organism while it was alive, such as animal tracks or feces.
These types of fossil are called trace fossils, as opposed to body fossils, past life leaves some markers that cannot be seen but can be detected in the form of biochemical signals, these are known as chemofossils or biosignatures. The process of fossilization varies according to type and external conditions. Permineralization is a process of fossilization that occurs when an organism is buried, the empty spaces within an organism become filled with mineral-rich groundwater. Minerals precipitate from the groundwater, occupying the empty spaces and this process can occur in very small spaces, such as within the cell wall of a plant cell. Small scale permineralization can produce very detailed fossils, for permineralization to occur, the organism must become covered by sediment soon after death or soon after the initial decay process. The degree to which the remains are decayed when covered determines the details of the fossil, some fossils consist only of skeletal remains or teeth, other fossils contain traces of skin, feathers or even soft tissues.
This is a form of diagenesis, in some cases the original remains of the organism completely dissolve or are otherwise destroyed. The remaining organism-shaped hole in the rock is called an external mold, if this hole is filled with other minerals, it is a cast. An endocast or internal mold is formed when sediments or minerals fill the cavity of an organism. This is a form of cast and mold formation. If the chemistry is right, the organism can act as a nucleus for the precipitation of minerals such as siderite, if this happens rapidly before significant decay to the organic tissue, very fine three-dimensional morphological detail can be preserved. Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization, replacement occurs when the shell, bone or other tissue is replaced with another mineral
Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate, about 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, most cave systems are through limestone bedrock. The first geologist to distinguish limestone from dolomite was Belsazar Hacquet in 1778, like most other sedimentary rocks, most limestone is composed of grains. Most grains in limestone are skeletal fragments of organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids and these organisms secrete shells made of aragonite or calcite, and leave these shells behind when they die. Limestone often contains variable amounts of silica in the form of chert or siliceous skeletal fragment, some limestones do not consist of grains at all, and are formed completely by the chemical precipitation of calcite or aragonite, i. e. travertine.
Secondary calcite may be deposited by supersaturated meteoric waters and this produces speleothems, such as stalagmites and stalactites. Another form taken by calcite is oolitic limestone, which can be recognized by its granular appearance, the primary source of the calcite in limestone is most commonly marine organisms. Some of these organisms can construct mounds of rock known as reefs, below about 3,000 meters, water pressure and temperature conditions cause the dissolution of calcite to increase nonlinearly, so limestone typically does not form in deeper waters. Limestones may form in lacustrine and evaporite depositional environments, calcite can be dissolved or precipitated by groundwater, depending on several factors, including the water temperature, pH, and dissolved ion concentrations. Calcite exhibits a characteristic called retrograde solubility, in which it becomes less soluble in water as the temperature increases. Impurities will cause limestones to exhibit different colors, especially with weathered surfaces, Limestone may be crystalline, granular, or massive, depending on the method of formation.
Crystals of calcite, dolomite or barite may line small cavities in the rock, when conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together, or it can fill fractures. Travertine is a banded, compact variety of limestone formed along streams, particularly there are waterfalls. Calcium carbonate is deposited where evaporation of the leaves a solution supersaturated with the chemical constituents of calcite. Tufa, a porous or cellular variety of travertine, is found near waterfalls, coquina is a poorly consolidated limestone composed of pieces of coral or shells. During regional metamorphism that occurs during the building process, limestone recrystallizes into marble
Mammoth Cave National Park
Mammoth Cave National Park is a U. S. national park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. Since the 1972 unification of Mammoth Cave with the system under Flint Ridge to the north. The park was established as a park on July 1,1941. It became a World Heritage Site on October 27,1981, the parks 52,830 acres are located primarily in Edmonson County, with small areas extending eastward into Hart County and Barren County. It is centered on the Green River, with a tributary, with 405 miles of surveyed passageways Mammoth Cave is by far the worlds longest known cave system, being over twice as long as the second-longest cave system, Mexicos Sac Actun underwater cave. Mammoth Cave developed in thick Mississippian-aged limestone strata capped by a layer of sandstone and it is known to include more than 390 miles of passageway, new discoveries and connections add several miles to this figure each year. Mammoth Cave National Park was established to preserve the cave system, the epikarstic zone concentrates local flows of runoff into high-elevation springs which emerge at the edges of ridges.
It is in underlying massive limestone layers that the human-explorable caves of the region have naturally developed. The limestone layers of the column beneath the Big Clifty, in increasing order of depth below the ridgetops, are the Girkin Formation. Genevieve Limestone, and the St. Louis Limestone, for example, the large Main Cave passage seen on the Historic Tour is located at the bottom of the Girkin and the top of the Ste. Each of the layers of limestone is divided further into named geological units and subunits. One area of research involves correlating the stratigraphy with the cave survey produced by explorers. This makes it possible to produce approximate three-dimensional maps of the contours of the layer boundaries without the necessity for test wells. The upper sandstone caprock is relatively hard for water to penetrate, the sandstone caprock layer has been dissolved and eroded at many locations within the park, such as the Frozen Niagara room. At one valley bottom in the region of the park.
Known as Cedar Sink, the features a small river entering one side. Mammoth Cave is home to the endangered Kentucky cave shrimp, a sightless albino shrimp, the National Park Service offers several cave tours to visitors. Some notable features of the cave, such as Grand Avenue, Frozen Niagara, two tours, lit only by visitor-carried paraffin lamps, are popular alternatives to the electric-lit routes