Iceberg

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https://en.wikipedia.org/wiki/Iceberg

An iceberg in the Arctic Ocean

An iceberg is a piece of freshwater ice more than 15 m long that has broken off a glacier or an ice shelf and is floating freely in open (salt) water.  Smaller chunks of floating glacially-derived ice are called "growlers" or "bergy bits". The sinking of the Titanic in 1912 led to the formation of the International Ice Patrol in 1914. Much of an iceberg is below the water's surface, which led to the expression "tip of the iceberg" to illustrate a small part of a larger unseen issue. Icebergs are considered a serious maritime hazard.

Icebergs vary considerably in size and shape. Icebergs that calve from glaciers in Greenland are often irregularly shaped while Antarctic ice shelves often produce large tabular (table top) icebergs. The largest iceberg in recent history, named B-15, was measured at nearly 300 by 40 kilometres (186 by 25 mi) in 2000. The largest iceberg on record was an Antarctic tabular iceberg measuring 335 by 97 kilometres (208 by 60 mi) sighted 240 kilometres (150 mi) west of Scott Island, in the South Pacific Ocean, by the USS Glacier on November 12, 1956. This iceberg was larger than Belgium.

Etymology

The word iceberg is a partial loan translation from the Dutch word ijsberg, literally meaning ice mountain, cognate to Danish isbjerg, German Eisberg, Low Saxon Iesbarg and Swedish isberg.

Overview

Typically about one-tenth of the volume of an iceberg is above water, which follows from Archimedes's Principle of buoyancy; the density of pure ice is about 920 kg/m³ (57 lb/cu ft), and that of seawater about 1,025 kg/m³ (64 lb/cu ft). The contour of the underwater portion can be difficult to judge by looking at the portion above the surface.

Northern edge of Iceberg B-15A in the Ross Sea, Antarctica, 29 January 2001

Iceberg size classifications according to the International Ice Patrol

Size class	Height (m)	Length (m)
Growler	<1	<5
Bergy bit	1–5	5–15
Small	5–15	15–60
Medium	15–45	60–122
Large	45–75	122–213
Very large	>75	>213

The largest icebergs recorded have been calved, or broken off, from the Ross Ice Shelf of Antarctica. Icebergs may reach a height of more than 100 metres (300 ft) above the sea surface and have mass ranging from about 100,000 tonnes up to more than 10 million tonnes. Icebergs or pieces of floating ice smaller than 5 meters above the sea surface are classified as "bergy bits"; smaller than 1 meter—"growlers". The largest known iceberg in the North Atlantic was 168 metres (551 ft) above sea level, reported by the USCG icebreaker Eastwind in 1958, making it the height of a 55-story building. These icebergs originate from the glaciers of western Greenland and may have interior temperatures of −15 to −20 °C (5 to −4 °F).

Grotto in an iceberg, photographed during the British Antarctic Expedition of 1911–1913, 5 Jan 1911

Drift

A given iceberg's trajectory through the ocean can be modelled by integrating the equation

${\displaystyle m\frac{d\overrightarrow{v}}{dt}=-mf\overrightarrow{k}\times \overrightarrow{v}+{\overrightarrow{F}}_{\text{a}}+{\overrightarrow{F}}_{\text{w}}+{\overrightarrow{F}}_{\text{r}}+{\overrightarrow{F}}_{\text{s}}+{\overrightarrow{F}}_{\text{p}},}$

where m is the iceberg mass, v the drift velocity, and the variables f, k, and F correspond to the Coriolis force, the vertical unit vector, and a given force. The subscripts a, w, r, s, and p correspond to the air drag, water drag, wave radiation force, sea ice drag, and the horizontal pressure gradient force.

Icebergs deteriorate through melting and fracturing, which changes the mass m, as well as the surface area, volume, and stability of the iceberg. Iceberg deterioration and drift, therefore, are interconnected iceberg thermodynamics, and fracturing must be considered when modelling iceberg drift.

Winds and currents may move icebergs close to coastlines, where they can become frozen into pack ice (one form of sea ice), or drift into shallow waters, where they can come into contact with the seabed, a phenomenon called seabed gouging.

Bubbles

Air trapped in snow forms bubbles as the snow is compressed to form firn and then glacial ice. Icebergs can contain up to 10% air bubbles by volume. These bubbles are released during melting, producing a fizzing sound that some may call "Bergie Seltzer". This sound results when the water-ice interface reaches compressed air bubbles trapped in the ice. As each bubble bursts it makes a "popping" sound and the acoustic properties of these bubbles can be used to study iceberg melt.

Stability

An iceberg may flip, or capsize, as it melts and breaks apart, changing the center of gravity. Capsizing can occur shortly after calving when the iceberg is young and establishing balance. Icebergs are unpredictable and can capsize anytime and without warning. Large icebergs that break off from a glacier front and flip onto the glacier face can push the entire glacier backwards momentarily, producing 'glacial earthquakes' that generate as much energy as an atomic bomb.

Color

Icebergs are generally white because they are covered in snow, but can be green, blue, yellow, black, striped, or even rainbow-colored. Seawater, algae and lack of air bubbles in the ice can create diverse colors. Sediment can create the dirty black coloration present in some icebergs.

Shape

Different shapes of icebergs

Tabular iceberg, near Brown Bluff in the Antarctic Sound off Tabarin Peninsula

In addition to size classification (Table 1), icebergs can be classified on the basis of their shapes. The two basic types of iceberg forms are tabular and non-tabular. Tabular icebergs have steep sides and a flat top, much like a plateau, with a length-to-height ratio of more than 5:1.

This type of iceberg, also known as an ice island, can be quite large, as in the case of Pobeda Ice Island. Antarctic icebergs formed by breaking off from an ice shelf, such as the Ross Ice Shelf or Filchner–Ronne Ice Shelf, are typically tabular. The largest icebergs in the world are formed this way.

Non-tabular icebergs have different shapes and include:

• Dome: An iceberg with a rounded top.
• Pinnacle: An iceberg with one or more spires.
• Wedge: An iceberg with a steep edge on one side and a slope on the opposite side.
• Dry-dock: An iceberg that has eroded to form a slot or channel.
• Blocky: An iceberg with steep, vertical sides and a flat top. It differs from tabular icebergs in that its aspect ratio, the ratio between its width and height, is small, more like that of a block than a flat sheet.

Monitoring and control

History

One of the icebergs suspected of sinking the RMS Titanic; a smudge of red paint much like the Titanic's red hull stripe was seen near its base at the waterline.

Prior to 1914 there was no system in place to track icebergs to guard ships against collisions. Despite fatal sinkings of ships by icebergs. In 1907, SS Kronprinz Wilhelm, a German liner, rammed an iceberg and suffered a crushed bow, but was still able to complete her voyage. The advent of water tight compartmentalization in ship construction led designers to declare their ships "unsinkable".

The April 1912 sinking of the Titanic, which killed more than 1,500 of its estimated 2,224 passengers and crew, discredited this claim. For the remainder of the ice season of that year, the United States Navy patrolled the waters and monitored ice movements. In November 1913, the International Conference on the Safety of Life at Sea met in London to devise a more permanent system of observing icebergs. Within three months the participating maritime nations had formed the International Ice Patrol (IIP). The goal of the IIP was to collect data on meteorology and oceanography to measure currents, ice-flow, ocean temperature, and salinity levels. They monitored iceberg dangers near the Grand Banks of Newfoundland and provided the "limits of all known ice" in that vicinity to the maritime community. The IIP published their first records in 1921, which allowed for a year-by-year comparison of iceberg movement.

Technological development

An iceberg being pushed by three U.S. Navy ships in McMurdo Sound, Antarctica

Aerial surveillance of the seas in the early 1930s allowed for the development of charter systems that could accurately detail the ocean currents and iceberg locations. In 1945, experiments tested the effectiveness of radar in detecting icebergs. A decade later, oceanographic monitoring outposts were established for the purpose of collecting data; these outposts continue to serve in environmental study. A computer was first installed on a ship for the purpose of oceanographic monitoring in 1964, which allowed for a faster evaluation of data. By the 1970s, ice-breaking ships were equipped with automatic transmissions of satellite photographs of ice in Antarctica. Systems for optical satellites had been developed but were still limited by weather conditions. In the 1980s, drifting buoys were used in Antarctic waters for oceanographic and climate research. They are equipped with sensors that measure ocean temperature and currents.

Side looking airborne radar (SLAR) made it possible to acquire images regardless of weather conditions. On November 4, 1995, Canada launched RADARSAT-1. Developed by the Canadian Space Agency, it provides images of Earth for scientific and commercial purposes. This system was the first to use synthetic aperture radar (SAR), which sends microwave energy to the ocean surface and records the reflections to track icebergs. The European Space Agency launched ENVISAT (an observation satellite that orbits the Earth's poles) on March 1, 2002. ENVISAT employs advanced synthetic aperture radar (ASAR) technology, which can detect changes in surface height accurately. The Canadian Space Agency launched RADARSAT-2 in December 2007, which uses SAR and multi-polarization modes and follows the same orbit path as RADARSAT-1.

Modern monitoring

Iceberg concentrations and size distributions are monitored worldwide by the U.S. National Ice Center (NIC), established in 1995, which produces analyses and forecasts of Arctic, Antarctic, Great Lakes and Chesapeake Bay ice conditions. More than 95% of the data used in its sea ice analyses are derived from the remote sensors on polar-orbiting satellites that survey these remote regions of the Earth.

Iceberg A22A in the South Atlantic Ocean

The NIC is the only organization that names and tracks all Antarctic Icebergs. It assigns each iceberg larger than 10 nautical miles (19 km) along at least one axis a name composed of a letter indicating its point of origin and a running number. The letters used are as follows:

A – longitude 0° to 90° W (Bellingshausen Sea, Weddell Sea)

B – longitude 90° W to 180° (Amundsen Sea, Eastern Ross Sea)

C – longitude 90° E to 180° (Western Ross Sea, Wilkes Land)

D – longitude 0° to 90° E (Amery Ice Shelf, Eastern Weddell Sea)

The Danish Meteorological Institute monitors iceberg populations around Greenland using data collected by the synthetic aperture radar (SAR) on the Sentinel-1 satellites.

Iceberg management

In Labrador and Newfoundland, iceberg management plans have been developed to protect offshore installations from impacts with icebergs.

Commercial use

In the late 2010s, a business from the UAE wanted to tow an iceberg from Antarctica to the Middle East, but the plan failed as the estimated cost of $200 million was too high. In 2019, a German company, Polewater, announced plans to tow Antarctic icebergs to places like South Africa.

Companies have used iceberg water in products such as bottled water, fizzy ice cubes and alcoholic drinks. For example, Iceberg Beer by Quidi Vidi Brewing Company is made from icebergs found around St. John's, Newfoundland. Although annual iceberg supply in Newfoundland and Labrador exceeds the total freshwater consumption of the United States, in 2016 the province introduced a tax on iceberg harvesting and imposed a limit on how much fresh water can be exported yearly.

Oceanography and ecology

Icebergs in Disko Bay

The freshwater injected into the ocean by melting icebergs can change the density of the seawater in the vicinity of the iceberg. Fresh melt water released at depth is lighter, and therefore more buoyant, than the surrounding seawater causing it to rise towards the surface. Icebergs can also act as floating breakwaters, impacting ocean waves.

Icebergs contain variable concentrations of nutrients and minerals that are released into the ocean during melting. Iceberg-derived nutrients, particularly the iron contained in sediments, can fuel blooms of phytoplankton. Samples collected from icebergs in Antarctica, Patagonia, Greenland, Svalbard, and Iceland, however, show that iron concentrations vary significantly, complicating efforts to generalize the impacts of icebergs on marine ecosystems.

Recent large icebergs

The calving of Iceberg A-38 off Filchner-Ronne Ice Shelf

Iceberg B15 calved from the Ross Ice Shelf in 2000 and initially had an area of 11,000 square kilometres (4,200 sq mi). It broke apart in November 2002. The largest remaining piece of it, Iceberg B-15A, with an area of 3,000 square kilometres (1,200 sq mi), was still the largest iceberg on Earth until it ran aground and split into several pieces October 27, 2005, an event that was observed by seismographs both on the iceberg and across Antarctica. It has been hypothesized that this breakup may also have been abetted by ocean swell generated by an Alaskan storm 6 days earlier and 13,500 kilometres (8,400 mi) away.

• 1987, Iceberg B-9, 5,390 km² (2,080 sq mi)
• 1998, Iceberg A-38, about 6,900 km² (2,700 sq mi)
• 1999, Iceberg B-17B 140 km² (54 sq mi), shipping alert issued December 2009.
• 2000, Iceberg B-15 11,000 km² (4,200 sq mi)
• 2002, Iceberg C-19, 5,500 km² (2,100 sq mi)
• 2002, Iceberg B-22, 5,490 km² (2,120 sq mi)
• 2003 broke off, Iceberg B-15A, 3,100 km² (1,200 sq mi)
• 2006, Iceberg D-16, 310 km² (120 sq mi)
• 2010, Ice sheet, 260 km² (100 sq mi), broken off of Petermann Glacier in northern Greenland on August 5, 2010, considered to be the largest Arctic iceberg since 1962. About a month later, this iceberg split into two pieces upon crashing into Joe Island in the Nares Strait next to Greenland. In June 2011, large fragments of the Petermann Ice Islands were observed off the Labrador coast.
• 2014, Iceberg B-31, 615 km² (237 sq mi), 2014
• 2017, Iceberg A-68, (Larsen C) 5,800 km² (2,200 sq mi)
• 2018, Iceberg B-46, 225 km² (87 sq mi)
• 2019, Iceberg D-28, 1,636 km² (632 sq mi)
• 2021, Iceberg A-74 from the Brunt Ice Shelf, 1,270 km² (490 sq mi)
• 2021, Iceberg A-76 from the Ronne Ice Shelf, 4,320 km² (1,670 sq mi)

In culture

One of the most prominently known icebergs in recorded history is that which sank the Titanic on 15 April 1912. Icebergs in both the northern and southern hemispheres have often been compared in size to multiples of the 59.1 square kilometres (22.8 sq mi)-area of Manhattan Island.

Exoskeleton

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https://en.wikipedia.org/wiki/Exoskeleton

Discarded exoskeleton (exuviae) of dragonfly nymph

Exoskeleton of cicada attached to a Tridax procumbens (colloquially known as the tridax daisy)

An exoskeleton (from Greek έξω éxō "outer" and σκελετός skeletós "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. Some large exoskeletons are known as "shells". Examples of exoskeletons within animals include the arthropod exoskeleton shared by chelicerates, myriapods, crustaceans, and insects, as well as the shell of certain sponges and the mollusc shell shared by snails, clams, tusk shells, chitons, and nautilus. Some animals, such as the turtle, have both an endoskeleton and an exoskeleton.

Role

Exoskeletons contain rigid and resistant components that fulfill a set of functional roles in many animals including protection, excretion, sensing, support, feeding, and acting as a barrier against desiccation in terrestrial organisms. Exoskeletons have roles in defense from pests and predator and in providing an attachment framework for musculature.

Arthropod exoskeletons contain chitin; the addition of calcium carbonate makes them harder and stronger, at the price of increased weight. Ingrowths of the arthropod exoskeleton known as apodemes serve as attachment sites for muscles. These structures are composed of chitin and are approximately six times stronger and twice the stiffness of vertebrate tendons. Similar to tendons, apodemes can stretch to store elastic energy for jumping, notably in locusts. Calcium carbonates constitute the shells of molluscs, brachiopods, and some tube-building polychaete worms. Silica forms the exoskeleton in the microscopic diatoms and radiolaria. One mollusk species, the scaly-foot gastropod, even uses the iron sulfides greigite and pyrite.

Some organisms, such as some foraminifera, agglutinate exoskeletons by sticking grains of sand and shell to their exterior. Contrary to a common misconception, echinoderms do not possess an exoskeleton and their test is always contained within a layer of living tissue.

Exoskeletons have evolved independently many times; 18 lineages evolved calcified exoskeletons alone. Further, other lineages have produced tough outer coatings, such as some mammals, that are analogous to an exoskeleton. This coating is constructed from bone in the armadillo, and hair in the pangolin. The armor of reptiles like turtles and dinosaurs like Ankylosaurs is constructed of bone; crocodiles have bony scutes and horny scales.

Growth

Main article: Ecdysis

Since exoskeletons are rigid, they present some limits to growth. Organisms with open shells can grow by adding new material to the aperture of their shell, as is the case in snails, bivalves, and other molluscans. A true exoskeleton, like that found in arthropods, must be shed (molted) when it is outgrown. A new exoskeleton is produced beneath the old one. The new skeleton is soft and pliable as the old one is shed. The animal will typically stay in a den or burrow for this time, as it is quite vulnerable during this period. Once at least partially set, the organism will plump itself up to try to expand the exoskeleton. The new exoskeleton is still capable of growing to some degree, however. In contrast, molting reptiles shed only the outer layer of skin and often exhibit indeterminate growth. These animals produce new skin and integuments throughout their life, replacing it according to growth. Arthropod growth, however, is limited by the space within its current exoskeleton. Failure to shed the exoskeleton once outgrown can result in the animal's death or prevent subadults from reaching maturity, thus preventing them from reproducing. This is the mechanism behind some insect pesticides, such as Azadirachtin.

Paleontological significance

Borings in exoskeletons can provide evidence of animal behavior. In this case, boring sponges attacked this hard clam shell after the death of the clam, producing the trace fossil Entobia.

Exoskeletons, as hard parts of organisms, are greatly useful in assisting the preservation of organisms, whose soft parts usually rot before they can be fossilized. Mineralized exoskeletons can be preserved as shell fragments. The possession of an exoskeleton permits a couple of other routes to fossilization. For instance, the strong layer can resist compaction, allowing a mold of the organism to be formed underneath the skeleton, which may later decay. Alternatively, exceptional preservation may result in chitin being mineralized, as in the Burgess Shale, or transformed to the resistant polymer keratin, which can resist decay and be recovered.

However, our dependence on fossilized skeletons also significantly limits our understanding of evolution. Only the parts of organisms that were already mineralized are usually preserved, such as the shells of molluscs. It helps that exoskeletons often contain "muscle scars", marks where muscles have been attached to the exoskeleton, which may allow the reconstruction of much of an organism's internal parts from its exoskeleton alone. The most significant limitation is that, although there are 30-plus phyla of living animals, two-thirds of these phyla have never been found as fossils, because most animal species are soft-bodied and decay before they can become fossilized.

Mineralized skeletons first appear in the fossil record shortly before the base of the Cambrian period, 550 million years ago. The evolution of a mineralized exoskeleton is considered a possible driving force of the Cambrian explosion of animal life, resulting in a diversification of predatory and defensive tactics. However, some Precambrian (Ediacaran) organisms produced tough outer shells while others, such as Cloudina, had a calcified exoskeleton. Some Cloudina shells even show evidence of predation, in the form of borings.

Evolution

Further information: Small shelly fauna

The fossil record primarily contains mineralized exoskeletons, since these are by far the most durable. Since most lineages with exoskeletons are thought to have started with a non-mineralized exoskeleton which they later mineralized, it is difficult to comment on the very early evolution of each lineage's exoskeleton. It is known, however, that in a very short course of time, just before the Cambrian period, exoskeletons made of various materials – silica, calcium phosphate, calcite, aragonite, and even glued-together mineral flakes – sprang up in a range of different environments. Most lineages adopted the form of calcium carbonate which was stable in the ocean at the time they first mineralized, and did not change from this mineral morph - even when it became less favorable.

Some Precambrian (Ediacaran) organisms produced tough but non-mineralized outer shells, while others, such as Cloudina, had a calcified exoskeleton, but mineralized skeletons did not become common until the beginning of the Cambrian period, with the rise of the "small shelly fauna". Just after the base of the Cambrian, these miniature fossils become diverse and abundant – this abruptness may be an illusion since the chemical conditions which preserved the small shells appeared at the same time. Most other shell-forming organisms appear during the Cambrian period, with the Bryozoans being the only calcifying phylum to appear later, in the Ordovician. The sudden appearance of shells has been linked to a change in ocean chemistry which made the calcium compounds of which the shells are constructed stable enough to be precipitated into a shell. However, this is unlikely to be a sufficient cause, as the main construction cost of shells is in creating the proteins and polysaccharides required for the shell's composite structure, not in the precipitation of the mineral components. Skeletonization also appeared at almost the same time that animals started burrowing to avoid predation, and one of the earliest exoskeletons was made of glued-together mineral flakes, suggesting that skeletonization was likewise a response to increased pressure from predators.

Ocean chemistry may also control which mineral shells are constructed of. Calcium carbonate has two forms, the stable calcite and the metastable aragonite, which is stable within a reasonable range of chemical environments but rapidly becomes unstable outside this range. When the oceans contain a relatively high proportion of magnesium compared to calcium, aragonite is more stable, but as the magnesium concentration drops, it becomes less stable, hence harder to incorporate into an exoskeleton, as it will tend to dissolve.

Except for the molluscs, whose shells often comprise both forms, most lineages use just one form of the mineral. The form used appears to reflect the seawater chemistry – thus which form was more easily precipitated – at the time that the lineage first evolved a calcified skeleton, and does not change thereafter. However, the relative abundance of calcite- and aragonite-using lineages does not reflect subsequent seawater chemistry – the magnesium/calcium ratio of the oceans appears to have a negligible impact on organisms' success, which is instead controlled mainly by how well they recover from mass extinctions. A recently discovered modern gastropod Chrysomallon squamiferum that lives near deep-sea hydrothermal vents illustrates the influence of both ancient and modern local chemical environments: its shell is made of aragonite, which is found in some of the earliest fossil mollusks; but it also has armor plates on the sides of its foot, and these are mineralized with the iron sulfides pyrite and greigite, which had never previously been found in any metazoan but whose ingredients are emitted in large quantities by the vents.

One true church

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https://en.wikipedia.org/wiki/One_true_church 

The expression "one true church" refers to an ecclesiological position asserting that Jesus gave his authority in the Great Commission solely to a particular visible Christian institutional church—what is commonly called a denomination. This view is maintained by the Catholic Church, the Eastern Orthodox Church, the Oriental Orthodox communion, the Assyrian Church of the East, the Ancient Church of the East, the Christian Churches/Churches of Christ, the Churches of Christ, and the Lutheran Churches, as well as certain Baptists. Each of them maintains that their own specific institutional church (denomination) exclusively represents the one and only original church. The claim to the title of the "one true church" relates to the first of the Four Marks of the Church mentioned in the Nicene Creed: "one, holy, catholic, and apostolic church". As such, it also relates to claims of both catholicity and apostolic succession: asserting inheritance of the spiritual, ecclesiastical and sacramental authority and responsibility that Jesus Christ gave to the apostles.

The concept of schism somewhat moderates the competing claims between some churches—one can potentially repair schism, since they are striving for the same goal. For example, the Catholic and Eastern Orthodox churches each regard the other as schismatic and at very least heterodox, if not heretical, yet both have held dialogues and even partaken in Councils in attempts to resolve the division that exists between them.

Many Mainline Protestants regard all baptized Christians as members of a spiritual—not institutional—"Christian Church" regardless of their differing beliefs; this belief is sometimes referred to by the theological term "invisible church". Some Anglicans of Anglo-Catholic churchmanship espouse a version of branch theory which teaches that the true Christian Church comprises Anglican, Eastern Orthodox, Old Catholic, Oriental Orthodox, Scandinavian Lutheran, Moravian, Persian, and Roman Catholic branches.

Other denominations, such as the Church of Jesus Christ of Latter-day Saints (LDS Church) also claim inheritance of the authority and responsibility that Jesus Christ conferred on the apostles. Other groups, such as Iglesia ni Cristo, believe in a last-messenger doctrine, where no such succession takes place. The Seventh-day Adventist Church regards itself to be the one true church in the sense of being a faithful remnant.

Teachings by denomination

Catholicism

Stained glass window in a Catholic church depicting St. Peter's Basilica in Rome sitting "Upon this rock," a reference to Matthew 16:18

The Roman Catholic Church teaches that Christ founded only "one true Church", and that this one true Church is the Catholic Church with the bishop of Rome (the pope) as its supreme, infallible head and locus of communion. From this follows that it regards itself as "the universal sacrament of salvation for the human race" and the "only true religion".

According to the Catechism of the Catholic Church, Catholic ecclesiology professes the Catholic Church to be the "sole Church of Christ"—i.e., the one true church defined as "one, holy, catholic, and apostolic" in the Four Marks of the Church in the Nicene Creed. The Council of Nicea (AD 325) originally formulated this teaching and ratified the Nicene Creed. The church teaches that only the Catholic Church was founded by Jesus Christ, who appointed the Twelve Apostles to continue his work as the Church's earliest bishops. Catholic belief holds that the Church "is the continuing presence of Jesus on earth", and that all duly-consecrated bishops have a lineal succession from the apostles. In particular, the Bishop of Rome (the Pope), is considered the successor to the apostle Simon Peter, from whom the Pope derives his supremacy over the Church. The 1943 papal encyclical Mystici corporis Christi further describes the Church as the Mystical Body of Christ. Thus the Catholic Church holds that "the one Church of Christ which in the Creed is professed as one, holy, catholic and apostolic ... This Church constituted and organized in the world as a society, subsists in the Catholic Church, which is governed by the successor of Peter and by the Bishops in communion with him." In Humani Generis, Pope Pius XII declared that "the Mystical Body of Christ and the Roman Catholic Church are one and the same thing." The Second Vatican Council repeated this teaching, stating in the Decree on the Eastern Churches: "The Holy Catholic Church, which is the Mystical Body of Christ, is made up of the faithful who are organically united in the Holy Spirit by the same faith, the same sacraments and the same government."

In responding to some questions regarding the doctrine of the Church concerning itself, the Vatican's Sacred Congregation for the Doctrine of the Faith stated, "Clarius dicendum esset veram Ecclesiam esse solam Ecclesiam catholicam romanam..." ("It should be said more clearly that the Roman Catholic Church alone is the true Church..") And it also clarified that the term subsistit in used in reference to the Church in the Second Vatican Council's 1964 decree Lumen gentium "indicates the full identity of the Church of Christ with the Catholic Church".

The 1215 Fourth Lateran Council declared that: "There is one universal Church of the faithful, outside of which there is absolutely no salvation", a statement of what is known as the doctrine of extra Ecclesiam nulla salus.

In the encyclical Mortalium animos of 6 January 1928, Pope Pius XI wrote that "in this one Church of Christ no man can be or remain who does not accept, recognize and obey the authority and supremacy of Peter and his legitimate successors" and quoted the statement of Lactantius: "The Catholic Church is alone in keeping the true worship. This is the fount of truth, this the house of Faith, this the temple of God: if any man enter not here, or if any man go forth from it, he is a stranger to the hope of life and salvation." Accordingly, the Second Vatican Council of 1962–1965 declared: "Whosoever, [...] knowing that the Catholic Church was made necessary by Christ, would refuse to enter or to remain in it, could not be saved. In the same document, the Council continued: "The Church recognizes that in many ways she is linked with those who, being baptized, are honored with the name of Christian, though they do not profess the faith in its entirety or do not preserve unity of communion with the successor of Peter." And in a decree on ecumenism, Unitatis redintegratio, it stated: "Catholics must gladly acknowledge and esteem the truly Christian endowments from our common heritage which are to be found among our separated brethren. It is right and salutary to recognise the riches of Christ and virtuous works in the lives of others who are bearing witness to Christ, sometimes even to the shedding of their blood. For God is always wonderful in His works and worthy of all praise."

The Catholic Church teaches that the fullness of the "means of salvation" exists only in the Catholic Church, but the church acknowledges that the Holy Spirit can make use of ecclesial communities separated from itself to "impel towards Catholic unity" and thus bring people to salvation in the Catholic Church ultimately. It teaches that anyone who is saved is saved through the Catholic Church but that people can be saved ex voto and by pre-baptismal martyrdom as well as when conditions of invincible ignorance are present, although invincible ignorance in itself is not a means of salvation.

Roman Catholic theology regards formal schismatics as outside the church, understanding by "formal schismatics" "persons who, knowing the true nature of the Church, have personally and deliberately committed the sin of schism". The situation, for instance, of those who have been brought up from childhood within a group not in communion with Rome, and who are acting in good faith and have maintained almost the entirety of the orthodox faith, differs. This nuanced view applies especially to the churches of Eastern Christianity, more particularly still to the Eastern Orthodox Church, though doctrinal impediments still remain, such as disagreement over the primacy of the Roman See, papal infallibility, the nature of Purgatory, indulgences, the Immaculate Conception, and a few other important doctrines.

Orthodoxy

The Eastern Orthodox Church (officially the Orthodox Catholic Church) identifies its confederative communion of Orthodox churches as the "One, Holy, Catholic, and Apostolic Church" of the Nicene-Constantinopolitan Creed and applies this title in conciliar and other official documents, for instance, in the Constantinople synods held in 1836 and 1838 and in correspondence with Pope Pius IX (r. 1846–1878) and with Pope Leo XIII (r. 1878–1903).

Lutheranism

...one holy Church is to continue forever. The Church is the congregation of saints, in which the Gospel is rightly taught and the Sacraments are rightly administered. — Augsburg Confession

The Lutheran Church views itself as the "main trunk of the historical Christian Tree" founded by Christ and the Apostles, holding that during the Reformation, the Church of Rome fell away. The Augsburg Confession found within the Book of Concord, a compendium of belief of the Lutheran Churches, teaches that "the faith as confessed by Luther and his followers is nothing new, but the true Catholic faith, and that their churches represent the true catholic or universal church". When the Lutherans presented the Augsburg Confession to Charles V, Holy Roman Emperor in 1530, they believe to have "showed that each article of faith and practice was true first of all to Holy Scripture, and then also to the teaching of the church fathers and the councils".

Lutheran theology therefore holds that:

There can only be one true visible Church. Of this our Catechism speaks in Question 192: "Whom do we call the true visible Church?" Answer: "The whole number of those who have, teach and confess the entire doctrine of the Word of God in all its purity, and among whom the Sacraments are duly administered according to Christ's institution." That there can be but one true visible Church, and that, therefore, one is not just as good as another stands to reason because there is only one truth, one Bible, one Word of God. Evidently that Church which teaches this truth, the whole truth, and nothing but the truth, is the true visible Church. Christ says John 8, 31. 32: "If ye continue in My Word, then are ye My disciples indeed; and ye shall know the truth, and the truth shall make you free." Again Christ says Matt. 28, 20: "Teaching them to observe all things whatsoever I have commanded you." Whatsoever He has commanded us, His Word, and nothing else, we should teach. And again, all things which He has commanded us we should teach. That, therefore is the true visible Church which does this. But that all visible Churches do not this is plain from the fact that they do not agree among themselves. If every Church would teach the whole truth and nothing but the truth as God has revealed it, there could be no difference. So, then, by calling other denominations Churches, we do not mean to say that one Church is just as good as another. Only that one is the true visible Church which teaches and confesses the entire doctrine of the Word of God in all its purity, and in whose midst the Sacraments are duly administered according to Christ's institution. Of all Churches, this can only be said of our Lutheran Church.

Laestadian Lutherans, in particular, emphasize this belief.

Baptists

Graph from The Trail of Blood, a popular Baptist book that teaches the doctrine of Baptist successionism.

Many Baptists, who uphold the doctrine of Baptist successionism (also known as Landmarkism), "argue that their history can be traced across the centuries to New Testament times" and "claim that Baptists have represented the true church" that "has been, present in every period of history". These Baptists maintain that those who held their views throughout history, including the "Montanists, Novatians, Patarenes, Bogomils, Paulicians, Arnoldists, Henricians, Albigenses, and Waldenses", were persecuted for their faith, a belief that these Baptists maintain to be "grand distinguishing mark of the true church". In the introduction of The Trail of Blood, a Baptist text that explicates the doctrine of Baptist succession, Clarence Walker states that "The history of Baptists, he discovered, was written in blood. They were the hated people of the Dark Ages. Their preachers and people were put into prison and untold numbers were put to death." J. M. Carroll, the author of the said text The Trail of Blood, also appeals to historian Johann Lorenz von Mosheim, who stated "Before the rise of Luther and Calvin, there lay secreted in almost all the countries of Europe persons who adhered tenaciously to the principles of modern Dutch Baptists." Walter B. Shurden, the founding executive director of the Center for Baptist Studies at Mercer University, writes that the theology of Landmarkism, which he states is integral of the history of the Southern Baptist Convention, upholds the ideas that "Only Baptist churches can trace their lineage in uninterrupted fashion back to the New Testament, and only Baptist churches therefore are true churches." In addition Shurden writes that Baptists who uphold successionism believe that "only a true church-that is, a Baptist church-can legitimately celebrate the ordinances of baptism and the Lord's Supper. Any celebration of these ordinances by non-Baptists is invalid."

Baptists who uphold this ecclesiology also do not characterize themselves as being a Protestant church due to their belief that "they did not descend from those churches that broke away in protest from the church of Rome. Rather, they had enjoyed a continuous historical existence from the time of the very first church in the New Testament days." These views are generally no longer widely held in the Southern Baptist Convention although they are still taught by some Southern Baptist Churches and many independent Baptist churches, Primitive Baptists (Reformed Baptists), and some "congregations affiliated with the American Baptist Association."

Anabaptists

An Amish family in Lyndonville, New York.

Amish

The Amish, as with other Anabaptist Christians, believe that "the established church became corrupt, ineffectual, and displeasing to God." The Amish believe that the true church is pure and separate from the world:

Amish fraternity is based upon the understanding of the church as a redemptive community. To express this corporateness they use the German term Gemeinde or the shorter dialect version pronounced Gemee. This concept expresses all the connotations of church, congregation, and community. The true church, they believe, had its origin in God's plan, and after the end of time the church will coexist with God through eternity. The true church is to be distinguished from the "fallen church". ... The church of God is composed of those who "have truly repented and rightly believed; who are rightly baptized ... and incorporated into the communion of saints on earth." The true church is "a chosen generation, a royal priesthood, an holy nation," and "a congregation of the righteous." The church of God is separate and completely different from the "bind perverted world." Furthermore, the church is "known by her evangelical faith, doctrine, love, and godly conversation; also by her pure walk and practice, and her observances of the true ordinances of Christ." The church must be "pure, unspotted and without blemish" (Eph. 5:27), capable of enforcing disciplinary measures to insure purity of life and separation from the world.

Holdeman Mennonites

The Holdeman Mennonites teach that their Church of God in Christ is the one true church. Anabaptist theologian Donald Kraybill writes:

Although similar in some ways to other conservative Mennonite groups, the Holdeman church teaches that they are the one true church of Christ. Their doctrine of the one true church, based on Matthew 16:18 and other Scriptures, emphasizes the succession of true doctrine, practice, and teachers through the centuries, and the authority of the church under Christ.

Quakers

As described in the tract The Glory of the True Church by Francis Howgill, the Religious Society of Friends traditionally believed that after the Apostolic Era, the "true Church fled into the wilderness" and "the false Church came into visibility". George Fox and his followers "believed that they were called to carry out the true reformation, to restore apostolic Christianity, and to make a fresh beginning". As such, "The Quaker community was the one true Church, and consequently those converted by Quaker preaching were expected to join it." Among some Quakers, there became a "shift from being the one and only True Church to being a part of the True Church" and so "marriage with non-Quakers became accepted by many in the Quaker community", though "they still had to marry within the Meeting House, as well as gain approbation."

Methodism

See also: Arminianism

Methodist preachers are known for promulgating the doctrines of the new birth and entire sanctification to the public at events such as tent revivals and camp meetings, which they believe is the reason that God raised them up into existence.

Methodists affirm belief in "the one true Church, Apostolic and Universal", viewing their Churches as constituting a "privileged branch of this true church". With regard to the position of Methodism within Christendom, the founder of the movement "John Wesley once noted that what God had achieved in the development of Methodism was no mere human endeavor but the work of God. As such it would be preserved by God so long as history remained." Calling it "the grand depositum" of the Methodist faith, Wesley specifically taught that the propagation of the doctrine of entire sanctification was the reason that God raised up the Methodists in the world.

Restorationism

A stained glass depiction of Joseph Smith's First Vision. He said that Jesus and God the Father told him that all the churches of his day were corrupt and abominable.

Restorationism is a broad category of churches, originating during the Second Great Awakening, that characterize themselves as a return to very early Christianity after the true faith was lost in a Great Apostasy. Prominent among these groups are the Christian churches and churches of Christ, the Churches of Christ (Stone-Campbell movement), the Christadelphians, and the Latter Day Saint movement (Mormonism). The idea of "restoration" was a popular theme of the time of the founding of these branches, and developed an independent expression in both. In the Stone-Campbell movement, the idea of restoration was combined with Enlightenment rationalism, "precluding emotionalism, spiritualism, or any other phenomena that could not be sustained by rational appeals to the biblical text."

Seventh-Day Adventist

The Seventh-Day Adventist Church (SDA Church) holds itself to be the one true church. It specifically teaches that "it is the 'final remnant' of His true church [spanning] the centuries". Seventh-day Adventist eschatology promulgates the idea that in the end times, there will be a "growing opposition between the 'true' church and the 'apostate' church." According to Seventh-day Adventist theology, these apostates are referred to as "Babylon", which they state is an amalgam of religions (including other Christian denominations) that worship on Sunday rather than the Lord's Sabbath, Saturday (Exodus 20:8–11). The SDA Church, in their view, "has drawn substantially on the biblical text, especially the books of Daniel and Revelation, to argue for its own status as the true remnant church which has a divine commission both to exist and to preach its apocalyptic message to the world at large."

Christian Conventions

Some small epsicopal church groups, such as the "Workers and Friends", represent themselves as nondenominational and hold all other churches to be false.

Latter Day Saint movement

Further information: Restoration (Latter Day Saints)

In 1830, Joseph Smith established the Church of Christ in the belief that it was a restoration of original Christianity. In 1831 he declared it to be "the only true and living church upon the face of the whole earth". Smith later reported in some versions of his First Vision in his teenage years, Jesus had told him that all churches that then existed "were all wrong; [and] that all their creeds were an abomination in his sight". The Latter Day Saints combined their religion with "the spirit of nineteenth-century Romanticism" and, as a result, "never sought to recover the forms and structures of the ancient church as ends in themselves" but "sought to restore the golden age, recorded in both Old Testament and New Testament, when God broke into human history and communed directly with humankind."

The predominant organization within the movement is the LDS Church, which continues to teach that it is "the only true and living church upon the face of the whole earth". The church teaches that all people who achieve the highest level of salvation must be baptized by one who holds the proper authority to perform such an ordinance; however, those who missed that opportunity in their lifetime may be included through a proxy baptism for the dead, in which a church member is baptized on their behalf inside a temple.

Most other Latter Day Saint churches claim to be the rightful continuation or successor of the church Smith established and therefore claim to be the one true church. However, the Community of Christ, the second-largest Latter Day Saint church, has recently de-emphasized this belief in favor of a position that the Community of Christ "is part of the whole body of Christ". The church's canonized Doctrine and Covenants continues to contain the declaration that the church is the "only true and living church".

Iglesia ni Cristo

The Iglesia ni Cristo (INC) a Philippine-based Christian religion, like other restorationist groups, professes that it is the one church founded by Jesus. Adherents hold that the Iglesia ni Cristo ("Church of Christ" in Tagalog) is the only true church of Jesus Christ as restored through a human instrument (sugo) Felix Manalo. The church recognizes Jesus Christ as the founder of the Christian Church. Meanwhile, its reestablishment is seen as the signal for the end of days. They believe that the church was apostatized by the 1st or 4th century due to false teachings. The INC says that this apostate church is the Roman Catholic Church.

Fear not for I am with you; I will bring your descendants from the east, And gather you from the west; I will say to the north, 'Give them up!' And to the south, 'Do not keep them back!' Bring My sons from afar, And My daughters from the ends of the earth.

— Isaiah 43:5–6

Members believe that the Iglesia ni Cristo is the fulfillment of the passage above. Based from their doctrines, "ends of the earth" pertains to the time the true church would be restored from apostasy and "east" refers to the Philippines where the "Church of Christ" would be founded. The INC teaches that its members constitute the "elect of God" and there is no salvation outside the INC. Faith alone is insufficient for salvation. The Iglesia ni Cristo says that the official name of the true church is "Church of Christ". The two passages often cited by INC to support this are Romans 16:16 "Greet one another with a holy kiss. All the churches of Christ greet you" and the George Lamsa translation of Acts 20:28: "Take heed therefore ... to feed the church of Christ which he has purchased with his blood."