Miscellany

Jai Ganesh · 2026-01-20 19:31:10

2476) Fractional Distillation

Gist

Fractional distillation is the most common form of separation technology used in petroleum refineries, petrochemical and chemical plants, natural gas processing and cryogenic air separation plants. In most cases, the distillation is operated at a continuous steady state.

Fractional distillation is a method to separate a liquid mixture into its parts (fractions) by heating it, relying on the components' different boiling points, especially when those boiling points are close (less than 25°C apart). It uses a fractionating column with obstacles to create multiple cycles of vaporization and condensation, allowing for a purer separation of components than simple distillation.

Summary

The various components of crude oil have different sizes, weights and boiling temperatures; so, the first step is to separate these components. Because they have different boiling temperatures, they can be separated easily by a process called fractional distillation. The steps of fractional distillation are as follows:

* You heat the mixture of two or more substances (liquids) with different boiling points to a high temperature. Heating is usually done with high pressure steam to temperatures of about 1112 degrees Fahrenheit / 600 degrees Celsius.
* The mixture boils, forming vapor (gases); most substances go into the vapor phase.
* The vapor enters the bottom of a long column (fractional distillation column) that is filled with trays or plates. The trays have many holes or bubble caps (like a loosened cap on a soda bottle) in them to allow the vapor to pass through. They increase the contact time between the vapor and the liquids in the column and help to collect liquids that form at various heights in the column. There is a temperature difference across the column (hot at the bottom, cool at the top).
* The vapor rises in the column.
* As the vapor rises through the trays in the column, it cools.
* When a substance in the vapor reaches a height where the temperature of the column is equal to that substance's boiling point, it will condense to form a liquid. (The substance with the lowest boiling point will condense at the highest point in the column; substances with higher boiling points will condense lower in the column.).
* The trays collect the various liquid fractions.
* The collected liquid fractions may pass to condensers, which cool them further, and then go to storage tanks, or they may go to other areas for further chemical processing.

Fractional distillation is useful for separating a mixture of substances with narrow differences in boiling points, and is the most important step in the refining process.

Very few of the components come out of the fractional distillation column ready for market. Many of them must be chemically processed to make other fractions. For example, only 40% of distilled crude oil is gasoline; however, gasoline is one of the major products made by oil companies. Rather than continually distilling large quantities of crude oil, oil companies chemically process some other fractions from the distillation column to make gasoline; this processing increases the yield of gasoline from each barrel of crude oil.

Details

Fractional distillation is the most common form of separation technology used in petroleum refineries, petrochemical and chemical plants, natural gas processing and cryogenic air separation plants. In most cases, the distillation is operated at a continuous steady state. New feed is always being added to the distillation column and products are always being removed. Unless the process is disturbed due to changes in feed, heat, ambient temperature, or condensing, the amount of feed being added and the amount of product being removed are normally equal. This is known as continuous, steady-state fractional distillation.

Industrial distillation is typically performed in large, vertical cylindrical columns known as "distillation or fractionation towers" or "distillation columns" with diameters ranging from about 0.65 to 6 meters (2 to 20 ft) and heights ranging from about 6 to 60 meters (20 to 197 ft) or more. The distillation towers have liquid outlets at intervals up the column which allow for the withdrawal of different fractions or products having different boiling points or boiling ranges. By increasing the temperature of the product inside the columns, the different products are separated. The "lightest" products (those with the lowest boiling point) exit from the top of the columns and the "heaviest" products (those with the highest boiling point) exit from the bottom of the column.

For example, fractional distillation is used in oil refineries to separate crude oil into useful substances (or fractions) having different hydrocarbons of different boiling points. The crude oil fractions with higher boiling points:

* have more carbon atoms
* have higher molecular weights
* are less branched-chain alkanes
* are darker in color
* are more viscous
* are more difficult to ignite and to burn

Large-scale industrial towers use reflux to achieve a more complete separation of products. Reflux refers to the portion of the condensed overhead liquid product from a distillation or fractionation tower that is returned to the upper part of the tower as shown in the schematic diagram of a typical, large-scale industrial distillation tower. Inside the tower, the reflux liquid flowing downwards provides the cooling needed to condense the vapors flowing upwards, thereby increasing the effectiveness of the distillation tower. The more reflux is provided for a given number of theoretical plates, the better the tower's separation of lower boiling materials from higher boiling materials. Alternatively, the more reflux provided for a given desired separation, the fewer theoretical plates are required.

Crude oil is separated into fractions by fractional distillation. The fractions at the top of the fractionating column have lower boiling points than the fractions at the bottom. All of the fractions are processed further in other refining units.

Fractional distillation is also used in air separation, producing liquid oxygen, liquid nitrogen, and highly concentrated argon. Distillation of chlorosilanes also enable the production of high-purity silicon for use as a semiconductor.

In industrial uses, sometimes a packing material is used in the column instead of trays, especially when low-pressure drops across the column are required, as when operating under vacuum. This packing material can either be random dumped packing (1–3 in (25–76 mm) wide) such as Raschig rings or structured sheet metal. Typical manufacturers are Koch, Sulzer, and other companies. Liquids tend to wet the surface of the packing and the vapors pass across this wetted surface, where mass transfer takes place. Unlike conventional tray distillation in which every tray represents a separate point of vapor liquid equilibrium the vapor-liquid equilibrium curve in a packed column is continuous. However, when modeling packed columns it is useful to compute several "theoretical plates" to denote the separation efficiency of the packed column concerning more traditional trays. Differently shaped packings have different surface areas and porosity. Both of these factors affect packing performance.

Design and operation of a distillation column depends on the feed and desired products. Given a simple, binary component feed, analytical methods such as the McCabe–Thiele method or the Fenske equation can be used. For a multi-component feed, simulation models are used both for design and operation.

Moreover, the efficiencies of the vapor-liquid contact devices (referred to as plates or trays) used in distillation columns are typically lower than that of a theoretical 100% efficient equilibrium stage. Hence, a distillation column needs more plates than the number of theoretical vapor-liquid equilibrium stages.

Reflux refers to the portion of the condensed overhead product that is returned to the tower. The reflux flowing downwards provides the cooling required for condensing the vapors flowing upwards. The reflux ratio, which is the ratio of the (internal) reflux to the overhead product, is conversely related to the theoretical number of stages required for efficient separation of the distillation products. Fractional distillation towers or columns are designed to achieve the required separation efficiently. The design of fractionation columns is normally made in two steps; a process design, followed by a mechanical design. The purpose of the process design is to calculate the number of required theoretical stages and stream flows including the reflux ratio, heat reflux, and other heat duties. The purpose of the mechanical design, on the other hand, is to select the tower internals, column diameter, and height. In most cases, the mechanical design of fractionation towers is not straightforward. For the efficient selection of tower internals and the accurate calculation of column height and diameter, many factors must be taken into account. Some of the factors involved in design calculations include feed load size and properties and the type of distillation column used.

The two major types of distillation columns used are tray and packing columns. Packing columns are normally used for smaller towers and loads that are corrosive or temperature-sensitive or for vacuum service where pressure drop is important. Tray columns, on the other hand, are used for larger columns with high liquid loads. They first appeared on the scene in the 1820s. In most oil refinery operations, tray columns are mainly used for the separation of petroleum fractions at different stages of oil refining.

In the oil refining industry, the design and operation of fractionation towers is still largely accomplished on an empirical basis. The calculations involved in the design of petroleum fractionation columns require in the usual practice the use of numerable charts, tables, and complex empirical equations. In recent years, however, a considerable amount of work has been done to develop efficient and reliable computer-aided design procedures for fractional distillation.

Additional Information

The inside of a fractional distilling column has sets of perforated trays. Each perforation is fitted with a bubble cap. Very hot, vaporized crude oil is pumped into the bottom of the column and rises up through the perforations. The bubble cap forces the oil vapor to bubble through liquid on the tray. This causes the vapor to cool as it flows upward and to condense into liquids. Excess liquid overflows through a pipe called a downcomer to the tray below. At various levels in the column, liquid is drawn off. The heavier products, such as straight-run heavy gas oil, are taken from the bottom part of the column and the lighter products, such as straight-run gasoline, are taken from the top. Straight-run natural gas comes out the top, and straight-run residuum comes out the bottom.

Jai Ganesh · 2026-01-21 16:44:30

2476) The Alps

The Alps

Gist

The Alps are Europe's highest and most extensive mountain range, forming a crescent across eight countries (France, Switzerland, Italy, Austria, Germany, Slovenia, Liechtenstein, Monaco), famous for Mont Blanc, Matterhorn, stunning scenery, skiing, biodiversity, and unique climate zones, originating from tectonic plate collision and providing vital water sources for Europe.

Which countries are in the Alps?

They stretch across eight countries: France, Switzerland, Italy, Monaco, Liechtenstein, Austria, Germany and Slovenia. The mountains were formed millions of years ago as two giant tectonic plates collided, creating some of the highest mountains in Europe, like the Matterhorn, Mont Blanc, and the Eiger.

Summary

The Alps are some of the highest and most extensive mountain ranges in Europe, stretching approximately 1,200 km (750 mi) across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria, Slovenia, and Hungary.

The Alpine arch extends from Nice on the western Mediterranean to Trieste on the Adriatic and Vienna at the beginning of the Pannonian Basin. The mountains were formed over tens of millions of years as the African and Eurasian tectonic plates collided. Extreme shortening caused by the event resulted in marine sedimentary rocks rising by thrusting and folding into high mountain peaks such as Mont Blanc and the Matterhorn.

Mont Blanc spans the French–Italian border, and at 4,809 m (15,778 ft) is the highest mountain in the Alps. The Alpine region area contains 82 peaks higher than 4,000 m (13,000 ft).

The altitude and size of the range affect the climate in Europe; in the mountains, precipitation levels vary greatly and climatic conditions consist of distinct zones. Wildlife such as ibex live in the higher peaks to elevations of 3,400 m (11,155 ft), and plants such as edelweiss grow in rocky areas in lower elevations as well as in higher elevations.

Evidence of human habitation in the Alps goes back to the Palaeolithic era. A mummified man ("Ötzi"), determined to be 5,000 years old, was discovered on a glacier at the Austrian–Italian border in 1991.

By the 6th century BC, the Celtic La Tène culture was well established. Hannibal notably crossed the Alps with a herd of elephants, and the Romans had settlements in the region. In 1800, Napoleon crossed one of the mountain passes with an army of 40,000. The 18th and 19th centuries saw an influx of naturalists, writers, and artists, in particular, the Romanticists, followed by the Golden Age of Alpinism as mountaineers began to ascend the peaks of the Alps.

The Alpine region has a strong cultural identity. Traditional practices such as farming, cheese making, and woodworking still thrive in Alpine villages. However, the tourist industry began to grow early in the 20th century and expanded significantly after World War II, eventually becoming the dominant industry by the end of the century.

The Winter Olympic Games have been hosted in the Swiss, French, Italian, Austrian and German Alps. As of 2010, the region is home to 14 million people and has 120 million annual visitors.

Details

Alps, a small segment of a discontinuous mountain chain that stretches from the Atlas Mountains of North Africa across southern Europe and Asia to beyond the Himalayas. The Alps extend north from the subtropical Mediterranean coast near Nice, France, to Lake Geneva before trending east-northeast to Vienna (at the Vienna Woods). There they touch the Danube River and meld with the adjacent plain. The Alps form part of France, Italy, Switzerland, Germany, Austria, Slovenia, Croatia, Bosnia and Herzegovina, Montenegro, Serbia, and Albania. Only Switzerland and Austria can be considered true Alpine countries, however. Some 750 miles (1,200 kilometres) long and more than 125 miles wide at their broadest point between Garmisch-Partenkirchen, Germany, and Verona, Italy, the Alps cover more than 80,000 square miles (207,000 square kilometres). They are the most prominent of western Europe’s physiographic regions.

Though they are not as high and extensive as other mountain systems uplifted during the Paleogene and Neogene periods (i.e., about 65 million to 2.6 million years ago)—such as the Himalayas and the Andes and Rocky mountains—they are responsible for major geographic phenomena. The Alpine crests isolate one European region from another and are the source of many of Europe’s major rivers, such as the Rhône, Rhine, Po, and numerous tributaries of the Danube. Thus, waters from the Alps ultimately reach the North, Mediterranean, Adriatic, and Black seas. Because of their arclike shape, the Alps separate the marine west-coast climates of Europe from the Mediterranean areas of France, Italy, and the Balkan region. Moreover, they create their own unique climate based on both the local differences in elevation and relief and the location of the mountains in relation to the frontal systems that cross Europe from west to east. Apart from tropical conditions, most of the other climates found on the Earth may be identified somewhere in the Alps, and contrasts are sharp.

A distinctive Alpine pastoral economy that evolved through the centuries has been modified since the 19th century by industry based on indigenous raw materials, such as the industries in the Mur and Mürz valleys of southern Austria that used iron ore from deposits near Eisenerz. Hydroelectric power development at the end of the 19th and beginning of the 20th centuries, often involving many different watersheds, led to the establishment in the lower valleys of electricity-dependent industries, manufacturing such products as aluminum, chemicals, and specialty steels. Tourism, which began in the 19th century in a modest way, became, after World War II, a mass phenomenon. Thus, the Alps are a summer and winter playground for millions of European urban dwellers and annually attract tourists from around the world. Because of this enormous human impact on a fragile physical and ecological environment, the Alps are likely the most threatened mountain system in the world.

Physical features:

Geology

The Alps emerged during the Alpine orogeny, an event that began about 65 million years ago as the Mesozoic Era was drawing to a close. A broad outline helps to clarify the main episodes of a complicated process. At the end of the Paleozoic Era, about 250 million years ago, eroded Hercynian mountains, similar to the present Massif Central in France and Bohemian Massif embracing parts of Germany, Austria, Poland, and the Czech Republic, stood where the Alps are now located. A large landmass, formed of crystalline rocks and known as Tyrrhenia, occupied what is today the western Mediterranean basin, whereas much of the rest of Europe was inundated by a vast sea. During the Mesozoic (about 250 million to 65 million years ago) Tyrrhenia was slowly leveled by the forces of erosion. The eroded materials were carried southward by river action and deposited at the bottom of a vast ocean known as the Tethys Sea, where they were slowly transformed into horizontal layers of rock composed of limestone, clay, shale, and sandstone.

About 44 million years ago, relentless and powerful pressures from the south first formed the Pyrenees and then the Alps, as the deep layers of rock that had settled into the Tethys Sea were folded around and against the crystalline bedrock and raised with the bedrock to heights approaching the present-day Himalayas. These tectonic movements lasted until 9 million years ago. Tyrrhenia sank at the beginning of the Quaternary Period, about 2.6 million years ago, but remnants of its mass, such as the rugged Estéral region west of Cannes, are still found in the western Mediterranean. Throughout the Quaternary Period, erosive forces gnawed steadily at the enormous block of newly folded and upthrust mountains, forming the general outlines of the present-day landscape.

The landscape was further modeled during the Quaternary by Alpine glaciation and by expanding ice tongues, some reaching depths of nearly 1 mile (1.6 kilometres), that filled in the valleys and overflowed onto the plains. Amphitheatre-like cirques, arête ridges, and majestic peaks such as the Matterhorn and Grossglockner were shaped from the mountaintops; the valleys were widened and deepened into general U-shapes, and immense waterfalls, like the Staubbach and Trümmelbach falls in the Lauterbrunnen Valley of the Bernese Alps, poured forth from hanging valleys hundreds of feet above the main valley floors; elongated lakes of great depth such as Lake Annecy in France, Lake Constance, bordering Switzerland, Germany, and Austria, and the lakes of the Salzkammergut in Austria filled in many of the ice-scoured valleys; and enormous quantities of sands and gravels were deposited by the melting glaciers, and landslides—following the melting of much of the ice—filled in sections of the valley floors. The hills east of Sierre in the Rhône valley are an example of this last phenomenon, and they mark the French–German language divide in this area.

When the ice left the main valleys, there was renewed river downcutting, both in the lateral and transverse valleys. The river valleys have been eroded to relatively low elevations that are well below those of the surrounding mountains. Thus, Aosta, Italy, in the Pennine Alps, and Sierre, Switzerland, look up to peaks that tower a mile and a half above them. In the valley of the Arve River near Mont Blanc, the difference in relief is more than 13,100 feet.

Glaciation therefore modified what otherwise would have been a harsher physical environment: the climate was much milder in the valleys than on the surrounding heights, settlement could be established deeper into the mountains, communication was facilitated, and soils were inherently more fertile because of morainic deposits. Vigorous glacial erosion continues in modern times. Many hundreds of square miles of Alpine glaciers, such as those in the Ortles and Adamello ranges and such deep-valley glaciers as the Aletsch Glacier near Brig, Switzerland, are still found in the Alps. The summer runoff from these ice masses is instrumental in filling the deep reservoirs used to generate hydroelectricity.

Physiography

The Alps present a great variety of elevations and shapes, ranging from the folded sediments forming the low-lying pre-Alps that border the main range everywhere except in northwestern Italy to the crystalline massifs of the inner Alps that include the Belledonne and Mont Blanc in France, the Aare and Gotthard in Switzerland, and the Tauern in Austria. From the Mediterranean to Vienna, the Alps are divided into Western, Central, and Eastern segments, each of which consists of several distinct ranges.

The Western Alps trend north from the coast through southeastern France and northwestern Italy to Lake Geneva and the Rhône valley in Switzerland. Their forms include the low-lying arid limestones of the Maritime Alps near the Mediterranean, the deep cleft of the Verdon Canyon in France, the crystalline peaks of the Mercantour Massif, and the glacier-covered dome of Mont Blanc, which at 15,771 feet (4,807 metres) is the highest peak in the Alps. Rivers from these ranges flow west into the Rhône and east into the Po.

The Central Alps occupy an area from the Great St. Bernard Pass east of Mont Blanc on the Swiss-Italian border to the region of the Splügen Pass north of Lake Como. Within this territory are such distinctive peaks as the Dufourspitze, Weisshorn, Matterhorn, and Finsteraarhorn, all 14,000 feet high. In addition, the great glacial lakes—Como and Maggiore in the south, part of the drainage system of the Po; and Thun, Brienz, and Lucerne (Vierwaldstättersee) in the north—fall within this zone.

The Eastern Alps, consisting in part of the Rätische range in Switzerland, the Dolomite Alps in Italy, the Bavarian Alps of southern Germany and western Austria, the Tauern Mountains in Austria, the Julian Alps in northeastern Italy and northern Slovenia, and the Dinaric Alps along the western edge of the Balkan Peninsula, generally have a northerly and southeasterly drainage pattern. The Inn, Lech, and Isar rivers in Germany and the Salzach and Enns in Austria flow into the Danube north of the Alps, while the Mur and Drau (Austria) and Sava (Balkan region) rivers discharge into the Danube east and southeast of the Alps. Within the Eastern Alps in Italy, Lake Garda drains into the Po, whereas the Adige, Piave, Tagliamento, and Isonzo pour into the Gulf of Venice.

Differences in relief within the Alps are considerable. The highest mountains, composed of autochthonous crystalline rocks, are found in the west in the Mont Blanc massif and also in the massif centring on Finsteraarhorn (14,022 feet) that divides the cantons of Valais and Bern. Other high chains include the crystalline rocks of the Mount Blanche nappe—which includes the Weisshorn (14,780 feet)—and the nappe of Monte Rosa Massif, sections of which mark the frontier between Switzerland and Italy. Farther to the east, Bernina Peak is the last of the giants over 13,120 feet (4,000 metres). In Austria the highest peak, the Grossglockner, reaches only 12,460 feet; Germany’s highest point, the Zugspitze in the Bavarian Alps, only 9,718 feet; and the highest point of Slovenia and the Julian Alps, Triglav, only 9,396 feet. Some of the lowest areas within the Western Alps are found at the delta of the Rhône River where the river enters Lake Geneva, 1,220 feet. In the valleys of the Eastern Alps north of Venice, elevations of only about 300 feet are common.

Climate of the Alps

The location of the Alps, as well as the great variations in their elevations and exposure, give rise to extreme differences in climate, not only among separate ranges but also within a particular range itself. Because of their central location in Europe, the Alps are affected by four main climatic influences: from the west flows the relatively mild, moist air of the Atlantic; cool or cold polar air descends from northern Europe; continental air masses, cold and dry in winter and hot in summer, dominate in the east; and, to the south, warm Mediterranean air flows northward. Daily weather is influenced by the location and passage of cyclonic storms and the direction of the accompanying winds as they pass over the mountains.

Temperature extremes and annual precipitation are related to the physiography of the Alps. The valley bottoms clearly stand out because generally they are warmer and drier than the surrounding heights. In winter nearly all precipitation above 5,000 feet is in the form of snow, and depths from 10 to 33 feet or more are common. Snow cover lasts from approximately mid-November to the end of May at the 6,600-foot level, blocking the high mountain passes; nevertheless, relatively snowless winters can occur. Mean January temperatures on the valley floors range from 23 to 39 °F (−5 to 4 °C) to as high as 46 °F (8 °C) in the mountains bordering the Mediterranean, whereas mean July temperatures range between 59 and 75 °F (15 and 24 °C). Temperature inversions are frequent, especially during autumn and winter, and the valleys often fill with fog and stagnant air for days at a time. At those times the levels above 3,300 feet can be warmer and sunnier than the low-lying valley bottoms. Winds can play a prominent role in daily weather and microclimatic conditions.

A foehn wind can last from two to three days and blows either south–north or north–south, depending on the tracking of cyclonic storms. The air mass of such a wind is cooled adiabatically as it passes upward to the mountain crests, which precipitates either rain or snow and retards the rate of cooling. When this drier air descends on the lee side, it is adiabatically warmed by compression at a constant rate and therefore has a higher temperature at the same altitude than when it began its upward flow. Snow in the affected areas disappears rapidly.

Avalanches, one of the great destructive forces of nature, are an ever-present danger during the period from late November to early June. Most follow well-defined paths, but much of the fear of avalanches is related to the difficulty of predicting where and when they will strike. Avalanches are a greater threat to human life and property in the Alps than in other mountain ranges because of the region’s relatively high population density and the tens of millions of tourists who visit each year. The development of ski resorts also has depleted many forests, which serve as natural barriers against avalanches.

Additional Information:

Geography:

The Alps are the highest and most extensive mountain range system that lie in south-central Europe. The mountain range stretches approximately 750 miles (1,200 kilometers) in a crescent shape across eight Alpine countries: France, Switzerland, Monaco, Italy, Liechtenstein, Austria, Germany, and Slovenia.

Ecology:

The Alps are an interzonal mountain system (Orobiome), or a “transition area” between Central and Mediterranean Europe. The Alps have high habitat diversity, with 200 habitats classified throughout the mountain range. This mountain range is home to a high level of biodiversity.

According to the World Wildlife Fund (WWF), there are over 4,500 species of plants, 200 bird species, 21 amphibian species, 15 reptile species, and 80 mammal species. Many of these species have made adaptations to the harsh cold conditions and high altitudes.

None of the 80 mammal species found in the Alps are “strictly” endemic, meaning they occur in the Alps and nowhere else in the world. Some of the larger carnivore species found in the Alps include the Eurasian lynx, the wolf, and the brown bear, and herbivores include the Alpine ibex, the chamois. These populations have been reduced in size or fragmented into small groups. There are also numerous rodent species found in the Alps, such as voles and marmots.

There are about 200 breeding bird species, as well as an equal number of migratory species, in the Alps. The largest bird species found in the Alps are the golden eagle and the bearded vulture. The alpine chough is the most common bird found in the region.

Of the 21 total species of amphibians, only one is endemic, Salamandra lanzai. There are fifteen reptile species present, including adders and vipers.

According to WWF, the Alps are one of the regions with the richest flora and fauna in Europe, second only to the Mediterranean. There are about 4,500 species of vascular plants, 800 species of mosses, 300 liverworts, 2500 lichens and more than 5000 fungi found in the Alps. About 8 percent of the vascular species are endemic. The variety of habitats in the Alps helps to promote the uniqueness of Alpine flora, along with the harsh environmental conditions that drive species to change and adapt.

Highest peak:

Mont Blanc is the highest peak at 15,776 feet (4,808 m). It is the second-highest and second most prominent mountain in Europe and the eleventh most prominent mountain summit in the world. The Mont Blanc massif spans across France, Italy, and Switzerland, while the summit itself lies on the border between France and Italy. There are about a hundred peaks higher than 13,000 ft (4,000 m) in the Alpine region.

Rivers:

The Alps provide lowland Europe with drinking water, irrigation, and hydroelectric power. Although the area is only about 11% of the surface area of Europe, the Alps provide up to 90% of water to lowland Europe. Major European rivers flow from the Alps, including the Rhine, the Rhône, the Inn, and the Po.

Glaciers:

The major glacierized areas in the Alps are situated along the crest of the mountain chain, with the largest glaciers often found at the highest elevations. There are smaller glaciers scattered throughout the Alps.

The Swiss Alps is known for glaciers, containing around 1,800 glaciers. The region’s glaciers include the longest glacier in the Alps: the Aletsch Glacier.

Additional Facts:

* At over 12 miles long and about a half-mile thick, the famous Aletsch valley glacier is the longest in the Alps, but due to climate change, the Aletsch is shrinking and predicted to completely melt by the end of this century.
* The Alps are Europe’s highest and most extensive mountain range.
* Mont Blanc is the highest mountain in the Alps, spanning 3 countries. Its granite ramparts distinguish it from other peaks. Mont Blanc’s ranges rose straight from the deep and are still rising, a phenomenon caused by glacial movement.
* The limestone Dolomites in Italy are half as high as Mont Blanc and were created as Africa’s collision with Europe pushed together an ancient tropical seafloor with the ancient skeletons of marine organisms into the sky.
* Humans have been living in the Alps since Paleolithic times, about 60,000 to 50,000 years ago. The Alpine region continues to have a strong cultural identity and its traditional culture of farming, cheesemaking, and woodworking still exists in Alpine villages. However, the tourism industry has been growing since the 20th century. While the region is home to 14 million people, it has 120 million annual visitors.

Jai Ganesh · 2026-01-22 22:59:01

2477) Photosysthesis

Gist

Photosynthesis is the vital process where plants, algae, and some bacteria use sunlight, water, and carbon dioxide to create their own food (glucose/sugars) and release oxygen, converting light energy into stored chemical energy, forming the base of most food webs and producing atmospheric oxygen. It involves light-dependent reactions (capturing energy in ATP/NADPH using chlorophyll) and light-independent reactions (Calvin Cycle) that use this energy to build sugars, occurring in chloroplasts.

Photosynthesis is the process where plants, algae, and some bacteria use sunlight, water, and carbon dioxide to create their own food (glucose/sugar) and release oxygen as a byproduct, converting light energy into stored chemical energy. This vital process, primarily occurring in chloroplasts, provides the energy and oxygen necessary for most life on Earth.

Summary

Photosynthesis is a system of biological processes by which photopigment-bearing autotrophic organisms, such as most plants, algae and cyanobacteria, convert light energy — typically from sunlight — into the chemical energy necessary to fuel their metabolism. The term photosynthesis usually refers to oxygenic photosynthesis, a process that releases oxygen as a byproduct of water splitting. Photosynthetic organisms store the converted chemical energy within the bonds of intracellular organic compounds (complex compounds containing carbon), typically carbohydrates like sugars (mainly glucose, fructose and sucrose), starches, phytoglycogen and cellulose. When needing to use this stored energy, an organism's cells then metabolize the organic compounds through cellular respiration. Photosynthesis plays a critical role in producing and maintaining the oxygen content of the Earth's atmosphere, and it supplies most of the biological energy necessary for complex life on Earth.

Some organisms also perform anoxygenic photosynthesis, which does not produce oxygen. Some bacteria (e.g. purple bacteria) use bacteriochlorophyll to split hydrogen sulfide as a reductant instead of water, releasing sulfur instead of oxygen, which was a dominant form of photosynthesis in the euxinic Canfield oceans during the Boring Billion. Archaea such as Halobacterium also perform a type of non-carbon-fixing anoxygenic photosynthesis, where the simpler photopigment retinal and its microbial rhodopsin derivatives are used to absorb green light and produce a proton (hydron) gradient across the cell membrane, and the subsequent ion movement powers transmembrane proton pumps to directly synthesize adenosine triphosphate (ATP), the "energy currency" of cells. Such archaeal photosynthesis might have been the earliest form of photosynthesis that evolved on Earth, as far back as the Paleoarchean, preceding that of cyanobacteria (see Purple Earth hypothesis).

While the details may differ between species, the process always begins when light energy is absorbed by the reaction centers, proteins that contain photosynthetic pigments or chromophores. In plants, these pigments are chlorophylls (a porphyrin derivative that absorbs the red and blue spectra of light, thus reflecting green) held inside chloroplasts, abundant in leaf cells. In cyanobacteria, they are embedded in the plasma membrane. In these light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, producing oxygen gas. The hydrogen freed by the splitting of water is used in the creation of two important molecules that participate in energetic processes: reduced nicotinamide adenine dinucleotide phosphate (NADPH) and ATP.

In plants, algae, and cyanobacteria, sugars are synthesized by a subsequent sequence of light-independent reactions called the Calvin cycle. In this process, atmospheric carbon dioxide is incorporated into already existing organic compounds, such as ribulose bisphosphate (RuBP). Using the ATP and NADPH produced by the light-dependent reactions, the resulting compounds are then reduced and removed to form further carbohydrates, such as glucose. In other bacteria, different mechanisms like the reverse Krebs cycle are used to achieve the same end.

The first photosynthetic organisms probably evolved early in the evolutionary history of life using reducing agents such as hydrogen or hydrogen sulfide, rather than water, as sources of electrons. Cyanobacteria appeared later; the excess oxygen they produced contributed directly to the oxygenation of the Earth, which rendered the evolution of complex life possible. The average rate of energy captured by global photosynthesis is approximately 130 terawatts, which is about eight times the total power consumption of human civilization. Photosynthetic organisms also convert around 100–115 billion tons (91–104 Pg petagrams, or billions of metric tons), of carbon into biomass per year. Photosynthesis was discovered in 1779 by Jan Ingenhousz who showed that plants need light, not just soil and water.

Details

Photosynthesis is the process by which green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds.

Importance of photosynthesis

It would be impossible to overestimate the importance of photosynthesis in the maintenance of life on Earth. The Great Oxidation Event, which began about 2.4 billion years ago and was largely driven by the photosynthetic cyanobacteria, raised atmospheric oxygen to nearly 1 percent of present levels over a span of 600 million years, paving the way for the evolution of most forms of multicellular life. Photosynthesis completely transformed Earth’s environment and biosphere. The life-giving process continues to sustain biodiversity since autotrophs are foundational to nearly every food web on the planet. If photosynthesis ceased, there would soon be little food or other organic matter on Earth. Most organisms would disappear, and in time Earth’s atmosphere would become nearly devoid of gaseous oxygen. The only organisms able to exist under such conditions would be the chemosynthetic bacteria, which can utilize the chemical energy of certain inorganic compounds and thus are not dependent on the conversion of light energy.

Energy produced by photosynthesis carried out by plants millions of years ago is responsible for the fossil fuels (i.e., coal, oil, and natural gas) that power industrial society. In past ages, green plants and small organisms that fed on plants increased faster than they were consumed, and their remains were deposited in Earth’s crust by sedimentation and other geological processes. There, protected from oxidation, these organic remains were slowly converted to fossil fuels. These fuels not only provide much of the energy used in factories, homes, and transportation but also serve as the raw material for plastics and other synthetic products. Unfortunately, modern civilization is using up in a few centuries the excess of photosynthetic production accumulated over millions of years. Consequently, the carbon dioxide that has been removed from the air to make carbohydrates in photosynthesis over millions of years is being returned at an incredibly rapid rate. The carbon dioxide concentration in Earth’s atmosphere is rising the fastest it ever has in Earth’s history, and this phenomenon—known as global warming—is expected to have major implications on Earth’s climate.

Evolution of the process

Although life and the quality of the atmosphere today depend on photosynthesis, it is likely that green plants evolved long after the first living cells. When Earth was young, electrical storms and solar radiation probably provided the energy for the synthesis of complex molecules from abundant simpler ones, such as water, ammonia, and methane. The first living cells probably evolved from these complex molecules. For example, the accidental joining (condensation) of the amino acid glycine and the fatty acid acetate may have formed complex organic molecules known as porphyrins. These molecules, in turn, may have evolved further into colored molecules called pigments—e.g., chlorophylls of green plants, bacteriochlorophyll of photosynthetic bacteria, hemin (the red pigment of blood), and cytochromes, a group of pigment molecules essential in both photosynthesis and cellular respiration.

Primitive colored cells then had to evolve mechanisms for using the light energy absorbed by their pigments. At first, the energy may have been used immediately to initiate reactions useful to the cell. As the process for using light energy continued to evolve, however, a larger part of the absorbed light energy probably was stored as chemical energy, to be used to maintain life. Green plants, with their ability to use light energy to convert carbon dioxide and water to carbohydrates and oxygen, are the culmination of this evolutionary process.

The first oxygenic (oxygen-producing) cells probably were the cyanobacteria (blue-green algae), which appeared about two billion to three billion years ago. These microscopic organisms are believed to have greatly increased the oxygen content of the atmosphere, making possible the development of aerobic (oxygen-using) organisms. Cyanophytes are prokaryotic cells; that is, they contain no distinct membrane-enclosed subcellular particles (organelles), such as nuclei and chloroplasts. Green plants, by contrast, are composed of eukaryotic cells, in which the photosynthetic apparatus is contained within membrane-bound chloroplasts. The complete genome sequences of cyanobacteria and higher plants provide evidence that the first photosynthetic eukaryotes were likely the red algae that developed when nonphotosynthetic eukaryotic cells engulfed cyanobacteria. Within the host cells, these cyanobacteria evolved into chloroplasts.

There are a number of photosynthetic bacteria that are not oxygenic (e.g., the sulfur bacteria previously discussed). The evolutionary pathway that led to these bacteria diverged from the one that resulted in oxygenic organisms. In addition to the absence of oxygen production, nonoxygenic photosynthesis differs from oxygenic photosynthesis in two other ways: light of longer wavelengths is absorbed and used by pigments called bacteriochlorophylls, and reduced compounds other than water (such as hydrogen sulfide or organic molecules) provide the electrons needed for the reduction of carbon dioxide.

Additional Information

Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.

Most life on Earth depends on photosynthesis.The process is carried out by plants, algae, and some types of bacteria, which capture energy from sunlight to produce oxygen (O2) and chemical energy stored in glucose (a sugar). Herbivores then obtain this energy by eating plants, and carnivores obtain it by eating herbivores.

The process

During photosynthesis, plants take in carbon dioxide (CO2) and water (H2O) from the air and soil. Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons. This transforms the water into oxygen and the carbon dioxide into glucose. The plant then releases the oxygen back into the air, and stores energy within the glucose molecules.

Chlorophyll

Inside the plant cell are small organelles called chloroplasts, which store the energy of sunlight. Within the thylakoid membranes of the chloroplast is a light-absorbing pigment called chlorophyll, which is responsible for giving the plant its green color. During photosynthesis, chlorophyll absorbs energy from blue- and red-light waves, and reflects green-light waves, making the plant appear green.

Light-dependent Reactions vs. Light-independent Reactions

While there are many steps behind the process of photosynthesis, it can be broken down into two major stages: light-dependent reactions and light-independent reactions. The light-dependent reaction takes place within the thylakoid membrane and requires a steady stream of sunlight, hence the name light-dependent reaction. The chlorophyll absorbs energy from the light waves, which is converted into chemical energy in the form of the molecules ATP and NADPH. The light-independent stage, also known as the Calvin cycle, takes place in the stroma, the space between the thylakoid membranes and the chloroplast membranes, and does not require light, hence the name light-independent reaction. During this stage, energy from the ATP and NADPH molecules is used to assemble carbohydrate molecules, like glucose, from carbon dioxide.

C3 and C4 Photosynthesis

Not all forms of photosynthesis are created equal, however. There are different types of photosynthesis, including C3 photosynthesis and C4 photosynthesis. C3 photosynthesis is used by the majority of plants. It involves producing a three-carbon compound called 3-phosphoglyceric acid during the Calvin Cycle, which goes on to become glucose. C4 photosynthesis, on the other hand, produces a four-carbon intermediate compound, which splits into carbon dioxide and a three-carbon compound during the Calvin Cycle. A benefit of C4 photosynthesis is that by producing higher levels of carbon, it allows plants to thrive in environments without much light or water.

Jai Ganesh · 2026-01-24 20:23:21

2478) Channel Tunnel

Channel Tunnel

Gist

The Channel Tunnel (often called the 'Chunnel' for short) is an undersea tunnel linking southern England and northern France. It is operated by the company Getlink, who also run a railway shuttle (Le Shuttle) between Folkestone and Calais, carrying passengers in cars, vans and other vehicles.

Which country owns the Channel tunnel?

To be specific, LeShuttle is operated by Getlink, the company which owns and operates the Channel Tunnel, the infrastructure connecting the UK with France. Eurostar is a customer of Getlink and runs its passenger trains through the tunnel.

How long are you underwater in the chunnel?

How long are you underwater on the Eurostar? It takes around 35 minutes for the Eurostar to cross the 23-mile underwater stretch of the Channel Tunnel.

Summary

The Channel Tunnel (French: Tunnel sous la Manche, sometimes referred to as the Chunnel) is a 50.46-kilometre (31.35-mile) railway tunnel beneath the English Channel that connects Folkestone in the United Kingdom with Coquelles in northern France. Opened in 1994, it remains the only fixed link between Great Britain and the European mainland.

The tunnel has the longest underwater section of any tunnel in the world, at 37.9 km (23.5 miles), reaching a depth of 75 m (246 ft) below sea level and runs, on average, 45 m (148 ft) below the seabed. It is the third-longest railway tunnel in the world. Although the tunnel was designed for speeds up to 200 km/h (120 mph), trains are limited to a maximum speed of 160 km/h (99 mph) for safety reasons. It connects to high-speed railway lines on either end: the LGV Nord in France and High Speed 1 in the United Kingdom.

The tunnel is operated by Getlink (formerly Eurotunnel) and is used by Eurostar high-speed passenger trains, LeShuttle services for road vehicles, and freight trains. In 2017, Eurostar trains carried 10.3 million passengers, freight trains transported 1.2 million tonnes (2.6 billion pounds) of freight, and LeShuttle trains moved 10.4 million passengers in 2.6 million cars and 51,000 coaches, and 1.6 million heavy goods vehicles carrying 21.3 million tonnes (47 billion pounds) of freight. That compares with 11.7 million passengers, 2.2 million cars, and 2.6 million heavy goods vehicles transported by sea through the Port of Dover.

Proposals for a cross-Channel tunnel date back as early as 1802, but concerns over national security delayed development. The modern project was initiated by Eurotunnel in 1988 and completed in 1994, at a final cost of £4.65 billion (equivalent to £11.7 billion in 2023). An engineering marvel, the Channel Tunnel was, at the time of its opening, by far the longest tunnel in Europe, and has only been surpassed by the Gotthard Base Tunnel in Switzerland. However, despite its engineering significance, several economic assessments have found that it has had only a limited positive economic impact on the British economy. Additionally, the tunnel has also experienced occasional service disruptions due to technical faults, fires, severe weather, and unauthorised access by migrants around Calais seeking entry to the United Kingdom.

Details

The Channel Tunnel (often called the 'Chunnel' for short) is an undersea tunnel linking southern England and northern France. It is operated by the company Getlink, who also run a railway shuttle (Le Shuttle) between Folkestone and Calais, carrying passengers in cars, vans and other vehicles.

Eurostar is a totally separate company and is Getlink’s biggest customer, running high-speed passenger services through the Channel Tunnel between London and a number of other European cities on the continent, including Paris, Brussels, Lille, Amsterdam and Rotterdam.

The Chunnel actually comprises three tunnels: two rail tunnels, used for freight and passenger trains, and a service tunnel.

How long is the Channel Tunnel?

The Channel Tunnel is 31.5 miles long or 50.45 km. That's the equivalent of 169 Eiffel Towers stacked on top of each other.

23.5 miles (37.9 km) of the Channel Tunnel is under the English Channel, making it the world's longest undersea tunnel.

What year did the Channel Tunnel open?

The idea of a tunnel under the Channel was first proposed in 1802 but construction wasn't started until 1988. It was completed in 1993, and Eurostar services started in November 1994.

What does the Eurotunnel look like underwater?

This may be a disappointing answer, but you can't actually see the sea from the Eurostar. When you go through the tunnel and look out of the window, all you can see is your reflection in the glass because it's quite dark outside. You can catch glimpses of the walls of the tunnel, of course, which are made of reinforced concrete.

Where is the Channel Tunnel?

The Channel Tunnel runs between Calais in northern France and Folkestone in south Kent. Vehicle traffic for Le Shuttle gets on in Calais and gets off in Folkestone. Calais is about three hour's drive from Paris and Folkestone is about an hour and a half's drive from London.

Our passenger-only Eurostar trains leave from St Pancras International station in London and go directly to the centre of Paris, Brussels and other Eurostar destinations in Europe.

How deep is the Channel Tunnel?

At its deepest, the tunnel is 75 metres (246 feet) below the sea level. That's the same as 107 baguettes balancing on top of each other.

The English Channel is much deeper than the tunnel, with its deepest point measuring 175 meters (574 feet) below sea level.

How was the Channel Tunnel built?

The Channel Tunnel is made of three separate tunnels running parallel to each other. One train tunnel running south (UK to France), one train tunnel running north (France to UK) and one service tunnel. All three tunnels were drilled below the seabed and link Folkestone in Kent to Coquelles in Pas-de-Calais.

However, the idea of connecting the UK and France by tunnel is much older than people think – dating back to the early 1800s when its supporters included Napoleon Bonaparte.

Work on experimental tunnels started back in 1880 at Abbot’s Cliff near Folkestone, Kent. Many of the workers used hand tools, but a state-of-the-art boring machine was also used. Work was eventually abandoned until construction on the tunnel as we now know it began again in 1988.

Frequently Asked Questions:

Thinking of hopping on Eurostar for your next European adventure? Got a couple of need-to-know questions before you book your trip? Here we’ve answered a selection of the most frequently asked questions from our customers.

Who can travel through the Channel Tunnel?

Foot passengers can travel with Eurostar, between our UK stations London St Pancras International and our stations on the continent . People who want to travel with their own vehicle or on a coach can use the Eurotunnel Le Shuttle between Folkestone and Calais. Before travelling with either Eurostar or Eurotunnel you will need to go through security, border and ticket checks before going through the Tunnel.

How much did it cost to build the Channel Tunnel?

It took just under six years and 13,000 workers to build the Channel Tunnel. The total cost came at an eye-watering £4.65 billion which would be the equivalent of £12 billion in today's money.

Why travel with Eurostar rather than drive?

* Avoid the stress of driving, with direct high-speed journeys to top destinations, from city centre to city centre.
* Great value fares with no additional costs like fuel, road tolls and parking.
* Simple connections with other rail services in Europe, allowing you to go beyond our direct destinations on a single booking.
* Travel in style on our comfortable trains, including our new, state-of-the art trains with wi-fi.

How fast does the Eurostar go?

The Eurostar travels through the Channel Tunnel at a speed of 100 miles per hour (160kph) although when the train is outside the tunnel it reaches speed of 186 miles per hour (300 kph).

Additional Information

Channel Tunnel, rail tunnel between England and France that runs beneath the English Channel. The Channel Tunnel, 50 km (31 miles) long, consists of three tunnels: two for rail traffic and a central tunnel for services and security. The tunnel runs between Folkestone, England, and Sangatte (near Calais), France, and is used for both freight and passenger traffic. Passengers can travel either by ordinary rail coach or within their own motor vehicles, which are loaded onto special railcars. Trains can travel through the tunnel at speeds as high as 160 km (100 miles) per hour; the trip takes about 35 minutes. It has the longest undersea portion of any tunnel in the world (37.8 km [23.5 miles]).

The often-considered idea of constructing a tunnel under the English Channel was revived in 1986 by the United Kingdom and France. A rail tunnel was chosen over proposals for a very long suspension bridge, a bridge-and-tunnel link, and a combined rail-and-road link, and the project was privately financed by a consortium of British and French corporations and banks; the Anglo-French company operating the tunnel is called Eurotunnel. Digging began on both sides of the Strait of Dover in 1987–88 and was completed in 1991. The tunnel was officially opened on May 6, 1994.

In 2007 the Channel Tunnel Rail Link (CTRL), also called High Speed 1, was opened to connect the Channel Tunnel with London, facilitating even greater movement of international passenger traffic between mainland Europe and the United Kingdom. The high-speed railway runs 108 km (67 miles) and crosses under the Thames. Its trains can reach speeds of up to 300 km (186 miles) per hour.

In June–July 2015 the problem of migrants—many of them from eastern Africa—sneaking aboard vehicles on trains in an attempt to immigrate to the United Kingdom reached crisis proportions. During that period at least nine individuals were killed while trying to make their way to England via the tunnel. The United Kingdom and France stepped up security measures to try to deter migrants from attempting the crossing.

Jai Ganesh · 2026-01-25 18:24:37

2479) Greenland Shark

Greenland Shark

Gist

Greenland sharks (Somniosus microcephalus) are the longest-lived vertebrates on Earth, with lifespans estimated between 250 and 500 years. A 2016 study using radiocarbon dating of eye lens proteins indicated they live at least 272 years, with some individuals estimated to be roughly 400 years old, and possibly up to 512 years.

The Greenland shark has the longest known lifespan of all vertebrate species. It is estimated that the species has a lifespan of at least 272 years, with the oldest individual estimated to be 392 ± 120 years of age.

Summary

Greenland sharks are now the longest-living vertebrates known on Earth, scientists say.

Researchers used radiocarbon dating to determine the ages of 28 of the animals, and estimated that one female was about 400 years old.

The team found that the sharks grow at just 1cm a year, and reach sexual maturity at about the age of 150.

The research is published, external in the journal Science.

Lead author Julius Nielsen, a marine biologist from the University of Copenhagen, external, said: "We had our expectations that we were dealing with an unusual animal, but I think everyone doing this research was very surprised to learn the sharks were as old as they were."

The former vertebrate record-holder was a bowhead whale estimated to be 211 years old.

But if invertebrates are brought into the longevity competition, a 507-year-old clam called Ming, external holds the title of most aged animal.

Slow swimmers

Greenland sharks are huge beasts, that can grow up to 5m in length.

They can be found, swimming slowly, throughout the cold, deep waters of the North Atlantic.

With this leisurely pace of life and sluggish growth rate, the sharks were thought to live for a long time. But until now, determining any ages was difficult.

For some fish, scientists are able to examine ear bones called otoliths, which when sectioned, show a pattern of concentric rings that scientists can count as they would the rings in a tree.

Sharks are harder, but some species, such as the Great White, have calcified tissue that grows in layers on their back bones, that can also be used to age the animals.

"But the Greenland shark is a very, very soft shark - it has no hard body parts where growth layers are deposited. So it was believed that the age could not be investigated," Mr Nielsen told the BBC.

However the team found a clever way of working out the age.

"The Greenland shark's eye lens is composed of a specialised material - and it contains proteins that are metabolically inert," explained Mr Neilson.

"Which means after the proteins have been synthesised in the body, they are not renewed any more. So we can isolate the tissue that formed when the shark was a pup, and do radiocarbon dating."

The team looked at 28 sharks, most of which had died after being caught in fishing nets as by-catch.

Using this technique, they established that the largest shark - a 5m-long female - was extremely ancient.

Because radiocarbon dating does not produce exact dates, they believe that she could have been as "young" as 272 or as old as 512. But she was most likely somewhere in the middle, so about 400 years old.

It means she was born between the years of 1501 and 1744, but her most likely date of birth was in the 17th century.

"Even with the lowest part of this uncertainty, 272 years, even if that is the maximum age, it should still be considered the longest-living vertebrate," said Mr Nielsen.

Conversely, if her age is at the upper end of the scale, she will have out-lived Ming the clam - although her age has a greater probability of lying in the middle.

Details

The Greenland shark (Somniosus microcephalus), also known as the rubiks shark or gray shark, is a large shark of the family Somniosidae ("sleeper sharks"), closely related to the Pacific and southern sleeper sharks. Inhabiting the North Atlantic and Arctic Oceans, they are notable for their exceptional longevity, although they are poorly studied due to the depth and remoteness of their natural habitat.

Greenland sharks have the longest lifespan of any known vertebrate, estimated to be between 250 and 500 years. They are among the largest extant shark species, reaching a maximum confirmed length of 6.4 m (21 ft) and weighing more than 1,000 kg (2,200 lb). They reach sexual maturity around 150 years of age and their pups are born alive after an estimated gestation period of 8 to 18 years. The shark is a generalist feeder, consuming a variety of available foods, including carrion.

Greenland shark meat is toxic to mammals due to its high levels of trimethylamine N-oxide, although a treated form of it is eaten in Iceland as a delicacy known as kæstur hákarl. Because they live deep in remote parts of the northern oceans, Greenland sharks are not considered a threat to humans. A possible attack occurred in August 1936 on two British fishermen, but the species was never identified.

Description

The Greenland shark is one of the largest known existing species of shark, with adults growing to around 4 to 5 m (13 to 16 ft). The largest confirmed specimen measured up to 6.4 metres (21 ft) long and weighed around 1,023 kilograms (2,255 lb). The all-tackle International Game Fish Association (IGFA) record for this species is 775 kg (1,709 lb). It rivals the Pacific sleeper shark (possibly up to 7 m or 23 ft long) for the largest species in the family Somniosidae. Genetic data indicate that Greenland sharks diverged from ancestral sleeper sharks in the Canadian Arctic approximately 1–2.34 million years ago during the Pleistocene epoch, likely influenced by glacial fluctuations that periodically isolated marine populations. These ecological challenges may have driven physiological and metabolic adaptations for cold, deep waters.

The Greenland shark is a thickset species, with a short, rounded snout, small eyes, and small dorsal and pectoral fins. The gill openings are very small for the species's great size. Females are typically larger than males, with males reaching maturity at a smaller size than females.

Coloration can range from pale creamy-gray to blackish-brown and the body is typically uniform in color, though whitish spots or faint dark streaks are occasionally seen on the back.

The shark is often infested by the copepod Ommatokoita elongata, a crustacean that attaches itself to the shark's eyes. The copepod may display bioluminescence, thus attracting prey for the shark in a mutualistic relationship, but this hypothesis has not been verified. These parasites can cause multiple forms of damage to the sharks' eyes, such as ulceration, mineralization, and edema of the cornea, leading to almost complete blindness. This does not seem to reduce the life expectancy or predatory ability of Greenland sharks, due to their strong reliance on smell and hearing.

The genome of the Greenland shark was published in 2024. It is 6.45 billion base pairs in length.

Dentition

The dentition of a Greenland shark:

When feeding on large carcasses, the shark employs a rolling motion of its jaw. The 48 to 52 teeth of the upper jaw are very thin and pointed, lacking serrations. These upper jaw teeth act as an anchor, while the lower jaw proceeds to cut massive chunks out of the prey.

The 48 to 52 lower teeth interlock, are broad and square in shape, and contain short, smooth cusps that point outward. Teeth in the two halves of the lower jaw are strongly pitched in opposite directions.

Physiology

Like other Elasmobranchii, Greenland sharks have high concentrations of the two nitrogenous compounds urea and trimethylamine N-oxide (TMAO) in their tissues, which increase their buoyancy and function as osmoprotectants. TMAO also counteracts the protein-destabilizing tendencies of urea and deep-water pressure. Its presence in the tissues of both elasmobranch and teleost fish has been found to increase with depth.

The blood of Greenland sharks contains three major types of hemoglobin, made up of two copies of α globin combined with two copies of three very similar β subunits. These three types show very similar oxygenation and carbonylation properties, which are unaffected by urea, an important compound in marine Elasmobranchii physiology. They display identical electronic absorption and resonance in Raman spectroscopy, indicating that their heme-pocket structures are identical or highly similar. The hemoglobins also have a lower affinity for oxygen compared to those of temperate sharks. These characteristics are believed to be adaptations to living at great depths.

When hoisted upon deck, it beats so violently with its tail, that it is dangerous to be near it, and the seamen generally dispatch it, without much loss of time. The pieces that are cut off exhibit a contraction of their muscular fibres for some time after life is extinct. It is, therefore, extremely difficult to kill, and unsafe to trust the hand within its mouth, even when the head is cut off. And, if we are to believe Crantz, this motion is to be observed three days after, if the part is trod on or struck.

— Henry William Dewhurst, The Natural History of the Order Cetacea (1834).

Additional Information

Greenland shark, (Somniosus microcephalus), member of the sleeper shark family Somniosidae (order Squaliformes, which also includes the dogfish family, Squalidae) also known for being the world’s longest-lived vertebrate. The species is primarily found in the cold-water environments of the Arctic Ocean and North Atlantic, from Baffin Bay eastward to the Barents Sea, but its range also extends southward to the North Sea and the waters adjacent to the Eastern Seaboard of the United States. Bulky, with a rounded snout, small fins relative to body size, and gray to brown coloration, Greenland sharks are similar to spiny dogfish (Squalus acanthias), except that they lack a spine in front of the second dorsal fin and usually the one on the first dorsal fin.

Natural history

The Greenland shark is one of the largest cartilaginous fishes. It can reach a length of 7 metres (23 feet) and a weight of 1,025 kg (2,260 pounds) when fully grown, but most are between 2 and 4 metres (6.5 and 13 feet). Little is known, however, about how the species reproduces. Females are thought to reach sexual maturity when they surpass the 4-metre (13-foot) mark in length, which takes approximately 150 years to achieve. They are ovoviviparous (that is, eggs are retained within the body until they hatch) and produce an average of 10 offspring at a time. The type, amount, and duration of parental care the young receive are unknown, but scientists speculate that, like other shark species, Greenland sharks are independent from birth. No other vertebrate known has a life span as long as this species, and a 2016 study that used radiocarbon dating to examine isotopes in the shark’s eye-lens nuclei suggested that the oldest Greenland sharks may be more than 500 years old. Using this technique, scientists estimated that the largest Greenland shark in the study was likely between 272 and 512 years old.

Greenland sharks are rarely encountered by humans. They are thought to prefer colder, deeper environments but may be found anywhere between the sea surface and depths of 2,200 meters (about 7,200 feet). Greenland sharks are slow-moving, typically swimming at rates of less than 3 km (about 1.9 miles) per hour.

They are carnivorous, and their diet is often made up of several different types of fishes, including smaller sharks, eels, flounders, and sculpins. Crustaceans, seabirds, and carrion—as well as terrestrial mammals (such as horses and reindeer) that likely fell through the ice—have been found in stomach analyses of the species. Greenland sharks are not considered dangerous to humans, in part because they live in regions where people do not typically swim; the only known report of a possible attack by a Greenland shark on a person dates to 1859.

Conservation status

The International Union for Conservation of Nature has classified the Greenland shark as a vulnerable species since 2020. The fish was valued historically for its liver oil; about 114 litres (30 gallons) of liver oil can be obtained from a large specimen (see also fish oil). (Although the flesh of the Greenland shark may be eaten, it is toxic unless properly cleaned and dried or repeatedly boiled prior to consumption.) They were fished commercially from the 19th century until 1960. Norway persecuted Greenland sharks during the 1970s, because they were considered to be a nuisance that threatened other fisheries. In the early 1900s as many as 30,000 Greenland sharks were caught a year. In the present day the annual take is far smaller; small-scale subsistence fisheries in the Arctic harvest fewer than 100 individuals annually, and roughly 1,200 are caught accidentally in fishing trawls.

Jai Ganesh · 2026-01-27 17:53:41

2480) Boric Acid

Gist

What is boric acid? Boric acid and its sodium borate salts are pesticides that we can find in nature and many products. Borax is one of the most common products. Boric acid and its sodium salts each combine boron with other elements in a different way.

Boric acid is a versatile compound used in medicine (antiseptic for minor issues, treating yeast infections), pest control (insecticide for ants, roaches), cosmetics, and numerous industrial applications, including fireproofing wood, manufacturing glass/ceramics, controlling nuclear fission, and as a component in lubricants and cleaners, valued for its anti-fungal, anti-bacterial, and preservative properties.

Summary

Boric acid, more specifically orthoboric acid, is a compound of boron, oxygen, and hydrogen with formula B(OH)3. It may also be called hydrogen orthoborate, trihydroxidoboron or boracic acid. It is usually encountered as colorless crystals or a white powder, that dissolves in water, and occurs in nature as the mineral sassolite. It is a weak acid that yields various borate anions and salts, and can react with alcohols to form borate esters.

Boric acid is often used as an antiseptic, insecticide, flame retardant, neutron absorber, or precursor to other boron compounds.

The term "boric acid" is also used generically for any oxyacid of boron, such as metaboric acid HBO2 and tetraboric acid H2B4O7.

Details

Boric acid exists in natural deposits as a mineral, sassolite. It is also found in hot mineral water sources. The minerals are extracted with sulfuric acid and crystalline boric acid is separated. Borates have been used since antiquity for cleaning and as food preservatives among other things. Boric acid was first registered for use in the United States as an insecticide in 1948. It has also been used as an antiseptic and was found in numerous commercial products.

Uses

Boric acid is used as a fireproofing agent for wood, as a preservative, and as an antiseptic. It is used in the manufacture of glass, pottery, enamels, glazes, cosmetics, cements, porcelain, leather, carpets, hats, soaps, artificial gems, and in tanning, printing, dyeing, painting, and photography. It is a constituent of nickel plating baths and electric condensers, and it is used for impregnating wicks and hardening steel. In laboratory procedures, boric acid is used in the preparation of buffer solutions.

Boric acid is also used as a fungicide and as an insecticide powder. Domestic use may include its application as an insecticide for crawling insects such as roaches. In medicine, it had been widely used as a disinfectant and a constituent of baby powders, antiseptics, diaper rash ointments, eye washes, gargles, and a variety of other consumer products for its mild antiseptic property. Its routine medical use, however, has fallen out of favor because of its relatively weak antiseptic action and its potential for toxicity,
although it may still be used to treat recurrent vulvovaginitis.

Additional Information:

What is Boric Acid?

Boric acid or H3BO3 is a water-soluble acidic compound that consists of Hydrogen, Boron, and Oxygen. It is a Lewis acid of Boron that is weak and monobasic in nature. Other names for Boric acid include Hydrogen Borate or Orthoboric acid. Its molar mass is 61.83 g/mol. According to the pH scale, Boric acid consists of a pH of 5.1, thus indicating that it is a weak monobasic acid.

What Are The Uses Of Boric Acid?

There are various uses of Boric acid. It is helpful as an antiseptic for minor cuts and/or burns. It is used as an anti-fungal ointment or powder and removes any foul odor of the feet by applying it inside stockings. It is also used for treating vaginal infections. Boric acid plays an effective role in pesticides and is effective against pests like rats, houseflies, math, etc. It can also be used to remove odors and dirt from kitchens and bathrooms.

Jai Ganesh · Yesterday 21:17:52

2481) New Guinea

Gist

The New Guinea bioregion, located in the Australasia realm, is the world's second largest island (after Greenland) separated from Australia by the Torres Strait. New Guinea and its surrounding islands make up the northernmost grouping of islands in Melanesia.

Summary

New Guinea is a big island north of Australia. It is the second largest island in the world. Geologically and biologically it is related to Australia. It was first surveyed by Alfred Russel Wallace in the 19th century, who noted that it was, like Australia, on the eastern side of the Wallace line. That means it is closer to Australia than to Indonesia in its flora and fauna.

On the east side of New Guinea is the country Papua New Guinea. On the west side of the island are the Indonesian provinces of Papua, Central Papua, Highland Papua, South Papua, Southwest Papua, and West Papua. These provinces together are called Western New Guinea. The Indonesian "capture" of western Papua New Guinea was a modern act by dictator Suharto of Indonesia. The Australian "capture" of the eastern half was meant to make sure the peoples of this part of Indonesia were left alone.

An early BBC David Attenborough program showed that the country was wooded with many groups of humans speaking many languages. The most notable animals still alive were the birds of paradise. Of marsupials, the quolls are notable. They are small, solitary carnivores. There are six species surviving, two in New Guinea and four in Australia. Echidnas are mammals also known as spiny anteaters.

The number of people on New Guinea is unknown. Indonesia and Papua New Guinea estimated the number around 2020. They say there are about 15 million people. However, the real number could be 23 million or more.

New Guinea is important for its nature and biology. Its largest marsupial, the Diprotodon, is now extinct. Native humans live in sparsely wooded, hilly ground in small groups which speak different languages. New Guinea has over 1000 languages. This is more languages than anywhere else in the world.

Still surviving are the birds of paradise, with marsupials, including wallabies and possums, and the egg-laying monotreme, the echidna. Other than bats and some two dozen indigenous rodents, there are no pre-human indigenous placental mammals. Pigs, several additional species of rats, and the ancestor of the New Guinea singing dog were introduced with human colonization.

Details

New Guinea (also known as Papua or historically Irian) is the world's second-largest island, with an area of 785,753 sq km (303,381 sq mi). It has the third-largest remaining rainforest globally, and the highest plant biodiversity of any island. Located in Melanesia in the southwestern Pacific Ocean, the island is separated from Australia by the 150-kilometre (81-nautical-mile; 93-mile) wide Torres Strait, though both landmasses lie on the same continental shelf, and were united during episodes of low sea level in the Pleistocene glaciations as the combined landmass of Sahul. Numerous smaller islands are located to the west and east. The island's name was given by Spanish explorer Yñigo Ortiz de Retez during his maritime expedition of 1545 because of the perceived resemblance of the indigenous peoples of the island to those in the African region of Guinea.

The eastern half of the island is the major land mass of the nation of Papua New Guinea. The western half, known as Western New Guinea, forms a part of Indonesia and is organized as the provinces of Papua, Central Papua, Highland Papua, South Papua, Southwest Papua, and West Papua. The two major cities on the island are Port Moresby and Jayapura.

Names

The island has been known by various names:

The name Papua was used to refer to parts of the island before contact with the West. Its etymology is unclear; one theory states that it derived from Tidore, the language used by the Sultanate of Tidore. An expedition by the Sultan of Tidore, together with Sahmardan, the Sangaji of Patani, and the Papuan Gurabesi, managed to conquer some areas in New Guinea, which was then reorganised to form Korano Ngaruha ("Four Kings") or Raja Ampat, Papoua Gam Sio (lit. "The Papua Nine Negeri"), and Mafor Soa Raha (lit. The Mafor "Four Soa"). The name comes from the words papo ("to unite") and ua (negation), which means "not united", i.e. an outlying possession of Tidore.

Anton Ploeg reports that the word papua is often said to be derived from the Malay word papua or pua-pua, meaning "frizzly-haired", referring to the very curly hair of the island's inhabitants. However Sollewijn Gelpke in 1993 considered this unlikely as it had been used earlier, and he instead derived it from the Biak phrase sup i babwa, which means "the land below [the sunset]", and refers to the Raja Ampat Islands.

When Portuguese and Spanish explorers arrived via the Spice Islands, they also used the name Papua. However, Westerners, beginning with Spanish explorer Yñigo Ortiz de Retez in 1545, used the name New Guinea, due to the resemblance between the indigenous peoples of the island and Africans of the Guinea region. The name is one of several toponyms sharing similar etymologies, ultimately meaning "land of the blacks" or similar meanings.

The Dutch, who arrived later under Jacob Le Maire and Willem Schouten, called it Schouten island. They later used this name only to refer to islands off the north coast of Papua proper, the Schouten Islands or Biak Island. When the Dutch colonized the main island as part of the Dutch East Indies, they called it Nieuw Guinea.

The name Irian was used in the Indonesian language to refer to the island and Indonesian province, as Irian Barat (West Irian) Province and later Irian Jaya Province. The name Irian was suggested during a tribal committee meeting in Tobati, Jayapura, formed by Soegoro Atmoprasodjo under governor J. P. van Eechoed, to decide on a new name because of the negative association of Papua. Frans Kaisiepo, the committee leader, suggested the name from Mansren Koreri myths, Iri-an from the Biak language of Biak Island, meaning "hot land" (referring to the climate), but also from Iryan which means heated process as a metaphor for a land that is entering a new era. In Serui Iri-an (lit. "land-nation") means "pillar of nation", while in Merauke Iri-an (lit. "placed higher-nation") means "rising spirit" or "to rise". The name was promoted in 1945 by Marcus Kaisiepo, brother of Frans Kaisiepo. The name was politicized later by Corinus Krey, Marthen Indey, Silas Papare, and others with the Indonesian backronym Ikut Republik Indonesia Anti Nederland ("Join the Republic of Indonesia Oppose the Netherlands"). Irian was used somewhat in 1972. The name was used until 2001, when Papua was again used for the island and the province. The name Irian, which was originally favored by natives, is now considered to be a name imposed by the Indonesian government.

Geography

New Guinea is an island to the north of the Australian mainland, south of the equator. It is isolated by the Arafura Sea to the west, and the Torres Strait and Coral Sea to the east. Sometimes considered to be the easternmost island of the Indonesian archipelago, it lies north of Australia's Top End, the Gulf of Carpentaria and Cape York Peninsula, and west of the Bismarck Archipelago and the Solomon Islands archipelago. Biologically, New Guinea may also be considered part of Australia, as there is a continuity of flora and fauna between the two countries.

Politically, the western half of the island comprises six provinces of Indonesia: Papua, Central Papua, Highland Papua, South Papua, West Papua and Southwest Papua. The eastern half forms the mainland of the country of Papua New Guinea.

The shape of New Guinea is often compared to that of a bird-of-paradise (indigenous to the island), and this results in the usual names for the two extremes of the island: the Bird's Head Peninsula in the northwest (Vogelkop in Dutch, Kepala Burung in Indonesian; also known as the Doberai Peninsula), and the Bird's Tail Peninsula in the southeast (also known as the Papuan Peninsula).

A spine of east–west mountains, the New Guinea Highlands, dominates the geography of New Guinea, stretching over 1,600 km (1,000 mi) across the island, with many mountains over 4,000 m (13,100 ft). The western half of the island contains the highest mountains in Oceania, with its highest point, Puncak Jaya, reaching an elevation of 4,884 m (16,023 ft). The tree line is around 4,000 m (13,100 ft) elevation, and the tallest peaks contain equatorial glaciers—which have been retreating since at least 1936. Various other smaller mountain ranges occur both north and west of the central ranges. Except in high elevations, most areas possess a warm humid climate throughout the year, with some seasonal variation associated with the northeast monsoon season.

Another major habitat feature is the vast southern and northern lowlands. Stretching for hundreds of kilometres, these include lowland rainforests, extensive wetlands, savanna grasslands, and some of the largest expanses of mangrove forest in the world. The southern lowlands are the site of Lorentz National Park, a UNESCO World Heritage Site. The northern lowlands are drained principally by the Mamberamo River and its tributaries on the western side, and by the Sepik on the eastern side. The more extensive southern lowlands are drained by a larger number of rivers, principally the Digul in the west and the Fly in the east. The largest island offshore, Dolak, lies near the Digul estuary, separated by a strait so narrow it has been named a "creek".

New Guinea contains many of the world's ecosystem types: glacial, alpine tundra, savanna, montane and lowland rainforest, mangroves, wetlands, lake and river ecosystems, seagrasses, and some of the richest coral reefs on the planet.

The entire length of the New Guinea Highlands system passes through New Guinea as a vast watershed. The northern rivers flow into the Pacific Ocean, the southern rivers into the Arafura Sea and the Gulf of Papua. On the north side, the largest rivers are the Mamberamo, Sepik and Ramu. Mamberamo was born from the confluence of two large inland rivers. Tariku comes from the west to the east and Taritatu from the east. These rivers meander through swamps with huge internal descents and then merge. The Mamberamo thus formed reaches the ocean by breaking through the Coastal Mountains. Mamberamo River is navigable to Marine Falls. The Sepik is a much more important river. Similarly, it collects water from a spacious pool. It is 1,100 kilometers from the Victor Emanuel Range to the estuary, making it the longest river in New Guinea. The winding, muddy, sluggish river can be navigated for 500 km. Ramu is a 650 km long river. Its lower section is navigable, but its upper flow is high-falling, fast-flowing. The energy of the river is used by a power plant near the city of Kainantu.

On the south side, the most significant rivers are Pulau, Digul, Fly, Kikori and Purari. The largest river in the western part of the island is Digul. It originates from the Star Mountains, which rise to an altitude of 4,700 m. The coastal plain is bordered by a swamp world hundreds of kilometers wide. Digul is the main transport route to the fertile hills and mountains within the island. The river Fly is born near the eastern branches of the Digul. It is named after one of the ships of the English Royal Fleet, which first sailed into the mouth of the river in 1845. The total length of the river is 1,050 km. Smaller boats can sail 900 km on the river. The estuary section, which decomposes into islands, is 70 km wide. The tide of the sea can have an effect of up to 300 kilometers. Strickland, a tributary of the Fly, reaches the Papuan Plain through wild gorges. Fly and Strickland together form the largest river in New Guinea. The many rivers flowing into the Gulf of Papua form a single delta complex. The rivers of the island are extremely rich in water due to the annual rainfall of 2,000–10,000 mm. According to a modest calculation, the New Guinea River carries about 1,500 {km}^{3}/a/(48,000 {m}^{3}/s) of water into the sea. Fly alone carries more water 238 {km}^{3}/a (7,500 {m}^{3}/s) than all the rivers in Australia combined.

Additional Information

New Guinea is an island of the eastern Malay Archipelago, in the western Pacific Ocean, north of Australia. It is bounded by the Pacific Ocean to the north, the Bismarck and Solomon seas to the east, the Coral Sea and Torres Strait to the south, and the Arafura Sea to the southwest. New Guinea is administratively divided into two parts: its western half comprises the Indonesian propinsi (or provinsi; provinces) of Papua and West Papua (collectively, formerly called Irian Jaya); and its eastern half comprises the major part of Papua New Guinea, an independent country since 1975.

New Guinea is the second largest island in the world, exceeded in size only by Greenland. It is about 1,500 miles (2,400 km) long (from northwest to southeast) and about 400 miles (650 km) wide at its widest (north to south) part. Area island, 317,150 square miles (821,400 square km). Pop. (2010) Papua and West Papua provinces including nearby islands, 3,593,803; (2011) Papua New Guinea excluding islands, 6,178,781.

Land

An unbroken chain of mountains with peaks above 13,000 feet (4,000 metres) in elevation extends across New Guinea from the northwest to the southeast, rising to 16,024 feet (4,884 metres) at Jaya Peak in western Papua province—the highest point in Indonesia. The summits of the chain are glaciated, and the mountains incorporate extinct volcanoes and elongated, fertile highland basins usually above 4,900 feet (1,490 metres) in elevation. To the north of the mountain chain is a deep structural trench occupied by the valleys of the Mamberamo, Sepik, Ramu, and Markham rivers. Fronting the north-central coastal plains of New Guinea is a series of fault-rimmed mountains that generally lie below 11,500 feet (3,500 metres). The mostly lowland Bomberai Peninsula and the more mountainous Doberai Peninsula constitute the extreme northwestern part of the island.

South of the central mountain chain is the Fly-Digul shelf, a vast swampy plain crossed by numerous rivers including the Fly, Bian, Digul, Mapi, Pulau, and Lorentz. To the southeast the Owen Stanley Range extends about 200 miles (320 km) and forms a wide peninsula, separating the Solomon Sea to the north from the Coral Sea to the south.

The climate of New Guinea is basically tropical, with mean annual maximum temperatures ranging between 86 and 90 °F (30 and 32 °C) in the lowlands; daytime temperatures in the highlands generally exceed 72 °F (22 °C) year-round. The southeast trade winds blow for about seven months each year, and rainfall on the southward-facing slopes of the central highlands frequently exceeds 300 inches (7,620 mm) annually. Consequently, the Fly-Digul shelf and bordering highlands are one of the world’s wettest places and also one of the least-inhabited. The central highlands receive rain throughout the year totaling between 100 and 160 inches (2,540 and 4,065 mm). Port Moresby on the southeastern coast receives only about 40 inches (1,000 mm) of rain per year.

New Guinea has a rich variety of plant life, including orchids, figs, and species of false beech. Mangrove swamps are found along the coastline almost everywhere. Farther inland mangroves are succeeded by nipa palms. Large stands of sago palms are found along the deltas and rivers of the southern coast. Primary lowland rainforest covers much of New Guinea up to about 3,300 feet (1,000 metres) above sea level. In the central highlands above 3,300 feet, stands of oak, beech, and pine are common. Wildlife includes many reptiles and such marsupials as the tree kangaroo and phalanger. Notable birds are the cassowary (a large, flightless bird), the spectacular birds of paradise, and parrots.

People

Almost the whole of New Guinea is occupied by speakers of Papuan languages, the original settlers of the island, who live mainly in the interior and southern sections. Papuan societies are characterized by leadership invested in local “big men” and by reciprocal gift giving. Ethnic composition is complex among the Papuans, who speak some 700 different languages. Constituting a small minority are communities of speakers of Austronesian (Melanesian) languages on the western, northern, and eastern coasts and on many of the affiliated offshore islands. There are also some Polynesians, Chinese, and Europeans. Several pidgins, such as Tok Pisin and Hiri Motu, are widely spoken; Indonesian (the official language of Indonesia) and English (the official language of Papua New Guinea) are also spoken. Although about two-thirds of Papua New Guinea’s population is Christian, traditional religious beliefs and rituals are still widely practiced.

Throughout most of the highland basins, much of the natural vegetation has been removed by the relatively intensive agriculture of the highlanders. The central highlands are the most densely populated part of the island. Swidden (slash-and-burn, or shifting) cultivation is practiced in the forested foothills to the north of the central highlands and in the grasslands of the Mamberamo and Sepik river basins, where the population is sparse. The north coast is also generally well populated.

Economy

Copper and gold are the main mineral resources of the island. One of the largest concentrations of copper in the world is at Tembagapura, about 25 miles (40 km) southwest of Mount Jaya in Papua. Another major deposit of copper has been developed just inside Papua New Guinea among the headwaters of the Fly River at Ok Tedi. Large amounts of gold also are produced at Ok Tedi. Petroleum is extracted in the Doberai Peninsula area of Papua and near Lake Kutubu in the central highlands of Papua New Guinea. Natural gas has been discovered in the Fly-Kikori area in Papua New Guinea.

The bulk of New Guinea’s population are subsistence farmers. Yams, taro, sago, and bananas are the lowland staple foods, and the sweet potato is the main highland food; pig husbandry is widespread. Cash crops in Papua New Guinea include coffee, cacao, copra, palm oil, tea, and rubber; skyjack tuna, prawns, and timber are also exported. Internal transport consists of a few secondary coastal roads, riverboats, and airways, with the latter becoming increasingly important.

History

New Guinea was possibly occupied as early as 50,000 years ago. By about 7000 bce sedentary agriculture with extensive swamp drainage and irrigation was practiced in the highland basins. The island, especially the western half, was known to Indonesian and Asian seafarers centuries before it was known to Europeans. The Portuguese in 1511 were the first Europeans to sight the island but made no landing until 1527.

The Dutch claimed the western half of the island in 1828 as part of the Dutch East Indies. In the 1870s Captain John Moresby of Great Britain surveyed the southeastern coast, and by 1884 the southeastern quadrant of New Guinea had been annexed by Great Britain. The German New Guinea Company took over administration of the northeast quadrant in the same year. The administration of British New Guinea was passed to Australia in 1904, and its name was changed to the Territory of Papua.

Following World War I, German New Guinea was taken over by Australia as a mandated territory of the League of Nations in 1921. After Japan temporarily occupied large parts of the island during the early years of World War II, Australia combined its administration of the Territory of Papua and the New Guinea mandate into the Territory of Papua and New Guinea. Also after the war, the western half of the island, then known as Irian Barat, was returned to Dutch control. Indonesia became independent in 1949, and a plebiscite was held in 1969 to decide Irian Barat’s future; as a result it was annexed to Indonesia. Papua New Guinea was granted independence within the British Commonwealth in 1975.

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