History.

The history of rail transport began in the 6th century BC in Ancient Greece. It can be divided up into several discrete periods defined by the principal means of track material and motive power used.

Ancient systems.

Evidence indicates that there was 6 to 8.5 km long "Diolkos" paved trackway, which transported boats across the Isthmus of Corinth in Greece from around 600 BC. Wheeled vehicles pulled

Pre-steam.

Wooden rails introduced.

In 1515, Cardinal Matthäus Lang wrote a description of the Reisszug, a funicular railway at the Hohensalzburg Fortress in Austria. The line originally used wooden rails and a hemp haulage rope and was operated by human or animal power, through a treadwheel. The line still exists and is operational, although in updated form and is possibly the oldest operational railway. Wagonways (or tramways) using wooden rails, hauled by horses, started appearing in the 1550s to facilitate the transport of ore tubs to and from mines, and soon became popular in Europe. Such an operation was illustrated in Germany in 1556 by Georgius Agricola in his work De re metallica. This line used "Hund" carts with unflanged wheels running on wooden planks and a vertical pin on the truck fitting into the gap between the

Metal rails introduced.

In the late 1760s, the Coalbrookdale Company began to fix plates of cast iron to the upper surface of the wooden rails. This allowed a variation of gauge to be used. At first only balloon loops could be used for turning, but later, movable points were taken into use that allowed for switching. A system was introduced in which unflanged wheels ran on L-shaped metal plates these became known as plateways. John Curr, a Sheffield colliery manager, invented this flanged rail in 1787, though the exact date of this is disputed. The plate rail was taken up by Benjamin Outram for wagonways serving his canals, manufacturing them at his Butterley ironworks. In 1803, William Jessop opened the Surrey Iron Railway, a double track plateway, erroneously sometimes cited as world's first public railway, in south London. Meanwhile, William Jessop had earlier used a form of all-iron edge rail and flanged wheels successfully for an extension to the Charnwood Forest Canal at Nanpantan, Loughborough, Leicestershire in 1789. In 1790, Jessop and his partner Outram began to manufacture edge-rails. Jessop became a partner in the Butterley Company in 1790. The first public edgeway (thus also first public railway) built was Lake Lock Rail Road in 1796. Although the primary purpose of the line was to carry coal, it also carried passengers.  These two systems of constructing iron railways, the "L" plate-rail and the smooth edge-rail, continued to exist side by side until well into the early 19th century. The flanged wheel and

Steam power introduced.

In 1784 James Watt, a Scottish inventor and mechanical engineer, patented a design for a steam locomotive. Watt had improved the steam engine of Thomas Newcomen, hitherto used to pump water out of mines, and developed a reciprocating engine in 1769 capable of powering a wheel. This was a large stationary engine, powering cotton mills and a variety of machinery; the state of boiler technology necessitated the use of low pressure steam acting upon a vacuum in the cylinder, which required a separate condenser and an air pump. Nevertheless, as the construction of boilers

Electric power introduced.

The first known electric locomotive was built in 1837 by chemist Robert Davidson of Aberdeen in Scotland, and it was powered by galvanic cells (batteries). Thus it was also the earliest battery electric locomotive. Davidson later built a larger locomotive named "Galvani", exhibited at the Royal Scottish Society of Arts Exhibition in 1841. The seven-ton vehicle had two direct-drive reluctance motors, with fixed electromagnets acting on iron bars attached to a wooden cylinder on each axle, and simple commutators. It hauled a load of six tons at four miles per hour (6 kilometers per hour) for a distance of. It was tested on the Edinburgh and Glasgow Railway in September of the following year, but the limited power from batteries prevented its general use. It was destroyed by railway workers, who

Diesel power introduced.

Earliest recorded examples of an internal combustion engine for railway use included a prototype designed by William Dent Priestman, which was examined by Sir William Thomson in 1888 who described it as a ""[Priestman oil engine] mounted upon a truck which is worked on a temporary line of rails to show the adaptation of a petroleum engine for locomotive purposes."". In 1894, a two axle machine built by Priestman Brothers was used on the Hull Docks.  In 1906, Rudolf Diesel, Adolf Klose and the steam and diesel engine manufacturer Gebrüder Sulzer founded Diesel-Sulzer-Klose GmbH to manufacture diesel-powered locomotives. Sulzer had been manufacturing diesel engines since 1898. The Prussian State Railways ordered a diesel locomotive from the company in 1909. The world's first diesel-powered locomotive was operated in the summer of 1912 on the Winterthur–Romanshorn railway in Switzerland, but was

High-speed rail.

Although steam and diesel services reaching speeds up to 200 km/h were started before the 1960s in Europe, they were not very successful. The first electrified high-speed rail Tōkaidō Shinkansen was introduced in 1964 between Tokyo and Osaka in Japan. Since then high-speed rail transport, functioning at speeds up to and above 300 km/h, has been built in Japan, Spain, France, Germany, Italy, the

Trains.

A train is a connected series of rail vehicles that move along the track. Propulsion for the train is provided by a separate locomotive or from individual motors in self-propelled multiple units. Most trains carry a revenue load, although non-revenue cars exist for the railway's own use, such as for maintenance-of-way purposes. The engine driver (engineer in North America) controls the locomotive or other power cars, although people movers and some rapid transits are under automatic control.

Haulage.

Traditionally, trains are pulled using a locomotive. This involves one or more powered vehicles being located at the front of the train, providing sufficient tractive force to haul the weight of the full train. This arrangement remains dominant for freight trains and is often used for passenger trains. A push–pull train has the end passenger car equipped with a driver's cab so that the engine driver can remotely control the locomotive. This allows one of the locomotive-hauled train's drawbacks to be removed, since the

Motive power.

Steam locomotives are locomotives with a steam engine that provides adhesion. Coal, petroleum, or wood is burned in a firebox, boiling water in the boiler to create pressurized steam. The steam travels through the smokebox before leaving via the chimney or smoke stack. In the process, it powers a piston that transmits power directly through a connecting rod (US: main rod) and a crankpin (US: wristpin) on the driving wheel (US main driver) or to a crank on a driving axle. Steam locomotives have been phased out in most parts of the world for economical and safety reasons, although many are preserved in working order by heritage railways.  Electric locomotives draw power from a stationary source via an overhead wire or third

Passenger trains.

A passenger train travels between stations where passengers may embark and disembark. The oversight of the train is the duty of a guard/train manager/conductor. Passenger trains are part of public transport and often make up the stem of the service, with buses feeding to stations. Passenger trains provide long-distance intercity travel, daily commuter trips, or local urban transit services. They even include a diversity of vehicles, operating speeds, right-of-way requirements, and service frequency. Passenger trains usually can be divided into two operations: intercity railway and intracity transit. Whereas intercity railway involve higher speeds, longer routes, and lower

Freight train.

A freight train hauls cargo using freight cars specialized for the type of goods. Freight trains are very efficient, with economy of scale and high energy efficiency. However, their use can be reduced by lack of flexibility, if there is need of transshipment at both ends of the trip due to lack of tracks to the points of pick-up and delivery. Authorities often encourage the use of cargo rail transport due to its fame.  Container trains have become the beta type in the US for bulk haulage. Containers can easily be transshipped to other modes, such as ships

Infrastructure.

Right of way.

Railway tracks are laid upon land owned or leased by the railway company. Owing to the desirability of maintaining modest grades, rails will often be laid in circuitous routes in hilly or mountainous terrain. Route length and grade requirements

Track.

Track consists of two parallel steel rails, anchored perpendicular to members called ties (sleepers) of timber, concrete, steel, or plastic to maintain a consistent distance apart, or rail gauge. Rail gauges are usually categorized as standard gauge (used on approximately 55% of the world's existing railway lines), broad gauge, and narrow gauge. In addition to the rail gauge, the tracks will be laid to conform with a Loading gauge which defines the maximum height and width for railway vehicles and their loads

Train inspection systems.

The inspection of railway equipment is essential for the safe movement of trains. Many types of defect detectors are in use on the world's railroads.

Signalling.

Railway signalling is a system used to control railway traffic safely to prevent trains from colliding. Being guided by fixed rails which generate low friction, trains are uniquely susceptible to collision since they frequently operate at speeds that do not enable them to stop quickly or within the driver's sighting distance; road vehicles, which encounter a higher level of friction between their rubber tyres and the road surface, have much shorter braking distances. Most forms of train control involve movement authority being passed from those responsible for each section of a rail network to the

Electrification.

The electrification system provides electrical energy to the trains, so they can operate without a prime mover on board. This allows lower operating costs, but requires large capital investments along the lines. Mainline and tram systems normally have overhead wires, which

Stations.

A railway station serves as an area where passengers can board and alight from trains. A goods station is a yard which is exclusively used for loading and unloading cargo. Large passenger stations have at least one building providing conveniences for passengers, such as purchasing tickets and food. Smaller stations typically only consist of a platform. Early stations were sometimes

Operations.

Ownership.

Since the 1980s, there has been an increasing trend to split up railway companies, with companies owning the rolling stock separated from those owning the infrastructure. This is particularly true in Europe, where this arrangement is required by the European Union. This has allowed open access by any train operator to any portion of the European railway network. In the UK, the railway track is state owned, with a public controlled

Financing.

The main source of income for railway companies is from ticket revenue (for passenger transport) and shipment fees for cargo. Discounts and monthly passes are sometimes available for frequent travellers (e.g. season ticket and rail pass). Freight revenue may be sold per container slot or for a whole train. Sometimes, the shipper owns the cars and only rents the haulage. For passenger transport, advertisement income can be significant.  Governments may choose to give subsidies to rail operation, since rail transport has fewer externalities than other dominant modes of transport. If the railway company is state-owned, the state may simply provide direct subsidies in exchange for increased production. If operations have been privatized, several options are available. Some

Safety.

Trains can travel at very high speed, but they are heavy, are unable to deviate from the track and require a great distance to stop. Possible accidents include derailment (jumping the track), a collision with another train or collision with automobiles, other vehicles or pedestrians at level crossings. The last accounts for the majority of rail accidents and casualties. The most important safety measures

Maintenance.

As in any infrastructure asset, railways must keep up with periodic inspection and maintenance in order to minimize effect of infrastructure failures that can disrupt freight revenue operations and passenger services. Because passengers are considered the most "crucial cargo" and usually operate at higher speeds, steeper grades, and higher capacity/frequency, their lines are especially important. Inspection practices include track geometry cars or walking inspection. Curve maintenance especially for transit services includes gauging, fastener tightening, and rail replacement.  Rail corrugation is a common issue with transit systems due to the high number of light-axle, wheel passages which result in grinding of the wheel/rail interface. Since maintenance

Social, economical, and energetic aspects.

Energy.

Rail transport is an energy-efficient but capital-intensive means of mechanized land transport. The tracks provide smooth and hard surfaces on which the wheels of the train can roll with a relatively low level of friction being generated. Moving a vehicle on and/or through a medium (land, sea, or air) requires that it overcomes resistance to its motion caused by friction. A land vehicle's total resistance (in pounds or Newtons) is a quadratic function of the vehicle's speed:  where:  Essentially, resistance differs between vehicle's contact point and surface of roadway. Metal wheels on metal rails have a significant advantage of overcoming resistance compared to rubber-tyred wheels on any road surface (railway 0.001g at and 0.024g at ; truck 0.009g at and 0.090 at ). In terms of cargo capacity combining speed and size being moved in a day:  In terms of the horsepower to weight ratio, a slow-moving barge requires, a railway and pipeline requires, and truck requires. However, at higher speeds, a railway overcomes the barge and proves most economical.  As an example, a typical modern wagon can hold up to of freight on two four-wheel bogies. The track distributes the weight of the train evenly, allowing significantly greater loads per axle and wheel than in road transport, leading to less wear and tear on the permanent way. This can save energy compared with other forms of transport, such as road transport, which depends on the friction between rubber tyres and the road. Trains have a small frontal area in relation to the load they are carrying, which reduces air resistance and thus energy usage.  In addition, the presence of track guiding the wheels allows for very long trains to be pulled by one or a few engines and driven by a single operator, even around curves, which allows for economies of scale in both manpower and energy use; by contrast, in road transport, more than two articulations causes fishtailing and makes the vehicle unsafe.

Energy efficiency.

Considering only the energy spent to move the means of transport, and using the example of the urban area of Lisbon, electric trains seem to be on average 20 times more efficient than automobiles for transportation of passengers, if we consider energy spent per passenger-distance with similar occupation ratios. Considering an automobile with a consumption of around of fuel, the average car in Europe has an occupancy of around 1.2 passengers per automobile (occupation ratio around 24%) and that one litre of fuel amounts to about, equating to an average of per passenger-km. This compares to a modern train with an average occupancy of 20% and a consumption of about, equating to per passenger-km, 20 times less than the automobile.

Usage.

Due to these benefits, rail transport is a major form of passenger and freight transport in many countries. It is ubiquitous in Europe, with an integrated network covering virtually the whole continent. In India, China, South Korea and Japan, many millions use trains as regular transport. In North America, freight rail transport is widespread and heavily used, but intercity passenger rail transport is relatively scarce outside the Northeast Corridor, due to increased preference of other modes,

Social and economic benefits.

Modernization.

Railways are central to the formation of modernity and ideas of progress. The process of modernization in the 19th century involved a transition from a spatially oriented world to a time oriented world. Exact time was essential, and everyone had to know what the time was, resulting in clocks towers for railway stations, clocks in public places, pocket watches for railway workers and for travelers. Trains left on time (they never left early). By contrast, in the premodern era, passenger ships left when the captain had enough passengers. In the premodern era, local time was set at noon, when the sun was at its highest. Every place east to

Model of corporate management.

According to historian Henry Adams the system of railroads needed: The impact can be examined through five aspects: shipping, finance, management, careers, and popular reaction.

Transportation.

Railways contribute to social vibrancy and economic competitiveness by transporting multitudes of customers and workers to city centres and inner suburbs. Hong Kong has recognized rail as "the backbone of the public transit system" and as such developed their franchised bus system

Wartime roles and air targets.

In the 1863-70 decade the heavy use of railways in the American Civil War, and in Germany's wars against Austria and France, provided a speed of movement unheard-of in the days of horses. During much of the 20th century, rail was a key element of war plans for rapid military mobilization, allowing for the quick

Negative impacts.

Railways channel growth towards dense city agglomerations and along their arteries, as opposed to highway expansion, indicative of the U.S. transportation policy, which encourages development of suburbs at the periphery, contributing to increased vehicle miles travelled, carbon emissions, development of greenfield spaces, and depletion of natural reserves. These arrangements revalue city spaces, local taxes, housing values, and promotion of mixed use development.  The construction of the first railway of the Austro-Hungarian empire, from Vienna to Prague, came in 1837–1842 to promises of new prosperity. Construction proved more costly than anticipated, and it brought in less revenue because local industry did not have a national market. In town after town the arrival of railway angered the locals because of the noise, smell, and pollution caused by the trains and the damage to homes and the surrounding land caused by the engine's soot and fiery embers; and since most travel was very local ordinary people seldom used the new line.

Pollution.

A 2018 study found that the opening of the Beijing Metro caused a reduction

Modern rail as economic development indicator.

European development economists have argued that the existence of modern rail infrastructure is a significant

Subsidies.

Asia.

Europe.

According to the 2017 European Railway Performance Index for intensity of use, quality of service and safety performance, the top tier European national rail systems consists of Switzerland, Denmark, Finland, Germany, Austria, Sweden, and France. Performance levels reveal a positive correlation between public cost and a given railway system's performance, and also reveal differences in the value that countries receive in return for their public cost. Denmark, Finland, France, Germany, the Netherlands, Sweden, and Switzerland capture relatively high value for their money, while Luxembourg, Belgium, Latvia, Slovakia, Portugal, Romania, and Bulgaria underperform relative to the average ratio of performance to cost among European countries.

North America.

Rail transport (also known as train transport) is a means of transferring passengers and goods on wheeled vehicles running on rails, which are located on tracks. In contrast to road transport, where vehicles run on a prepared flat surface, rail vehicles (rolling stock) are directionally guided by the tracks on which they run. Tracks usually consist of steel rails, installed on ties (sleepers) set in ballast, on which the rolling stock, usually fitted with metal wheels, moves. Other variations are also possible, such as slab track. This is where the rails are fastened to a concrete foundation resting on a prepared subsurface.

Železniční doprava je kolejová doprava provozovaná na železniční dráze. Obvykle ji vykonává železniční společnost. Proti silniční dopravě se kolejová doprava vyznačuje relativně nízkou spotřebou energie na tunokilometr. Je to dáno nízkým valivým odporem soustavy kolo – kolejnice.


Naming.

Meteorites are always named for the places they were found, where practical, usually a nearby town or geographic feature. In cases where many meteorites were found in one place, the name may be followed by a number or letter (e.g., Allan Hills 84001 or Dimmitt (b)). The name designated by the Meteoritical Society is used by scientists, catalogers, and most collectors.

Fall phenomena.

Most meteoroids disintegrate when entering the Earth's atmosphere. Usually, five to ten a year are observed to fall and are subsequently recovered and made known to scientists. Few meteorites are large enough to create large impact craters. Instead, they typically arrive at the surface at their terminal velocity and, at most, create a small pit.  Large meteoroids may strike the earth with a significant fraction of their escape velocity (second cosmic velocity), leaving behind a hypervelocity impact crater. The kind of crater will depend on the size, composition, degree of fragmentation, and incoming angle of the impactor. The force of such collisions has the potential to cause widespread destruction. The most frequent hypervelocity cratering events on the Earth are caused by iron meteoroids, which are most easily able to transit the atmosphere intact. Examples of craters caused by iron meteoroids include Barringer Meteor Crater, Odessa Meteor Crater, Wabar craters, and Wolfe Creek crater; iron meteorites are found in association with all of these craters. In contrast, even relatively large stony or icy bodies like small comets or asteroids, up to millions of tons, are disrupted in the atmosphere, and do not make impact craters. Although such disruption events are uncommon, they can cause a considerable concussion to occur; the famed Tunguska event probably resulted from such an incident. Very large stony objects, hundreds of meters in diameter or more, weighing tens of millions of tons or more, can reach the surface and cause large craters but are very rare. Such events are generally so energetic that the impactor is completely destroyed, leaving no meteorites. (The very first example of a stony meteorite found in association with a large impact crater, the Morokweng crater in South Africa, was reported in May 2006.)  Several phenomena are well documented during witnessed meteorite falls too small to produce hypervelocity craters. The fireball that occurs as the meteoroid passes through the atmosphere can appear to be very bright, rivaling the sun in intensity, although most are far dimmer and may not even be noticed during the daytime. Various colors have been reported, including yellow, green, and red. Flashes and bursts of light can occur as the object breaks up. Explosions, detonations, and rumblings are often heard during meteorite falls, which can be caused by sonic booms as well as shock waves resulting from major fragmentation events. These sounds can be heard over wide areas, with a radius of a hundred or more kilometers. Whistling and hissing sounds are also sometimes heard but are poorly understood. Following the passage of the fireball, it is not unusual for a dust trail to linger in the atmosphere for several minutes.  As meteoroids are heated during atmospheric entry, their surfaces melt and experience ablation. They can be sculpted into various shapes during this process, sometimes resulting in shallow thumbprint-like indentations on their surfaces called regmaglypts. If the meteoroid maintains a fixed orientation for some time, without tumbling, it may develop a conical "nose cone" or "heat shield" shape. As it decelerates, eventually the molten surface layer solidifies into a thin fusion crust, which on most meteorites is black (on some achondrites, the fusion crust may be very light-colored). On stony meteorites, the heat-affected zone is at most a few mm deep; in iron meteorites, which are more thermally conductive, the structure of the metal may be affected by heat up to below the surface. Reports vary; some meteorites are reported to be "burning hot to the touch" upon landing, while others are alleged to have been cold enough to condense water and form a frost.  Meteoroids that experience disruption in the atmosphere may fall as meteorite showers, which can range from only a few up to thousands of separate individuals. The area over which a meteorite shower falls is known as its strewn field. Strewn fields are commonly elliptical in shape, with the major axis parallel to the direction of flight. In most cases, the largest meteorites in a shower are found farthest down-range in the strewn field.

Meteorite types.

Most meteorites are stony meteorites, classed as chondrites and achondrites. Only about 6% of meteorites are iron meteorites or a blend of rock and metal, the stony-iron meteorites. Modern classification of meteorites is complex. The review paper of Krot et al. (2007) summarizes modern meteorite taxonomy.  About 86% of the meteorites are chondrites, which are named for the small, round particles they contain. These particles, or chondrules, are composed mostly of silicate minerals that appear to have been melted while they were free-floating objects in space. Certain types of chondrites also contain small amounts of organic matter, including amino acids, and presolar grains. Chondrites are typically about 4.55 billion years old and are thought to represent material from the asteroid belt that never coalesced into large bodies. Like comets, chondritic asteroids are some of the oldest and most primitive materials in the solar system. Chondrites are often considered to be "the building blocks of the planets".  About 8% of the meteorites are achondrites (meaning they do not contain chondrules), some of which are similar to terrestrial igneous rocks. Most achondrites are also ancient rocks, and are thought to represent crustal material of differentiated planetesimals. One large family of achondrites (the HED meteorites) may have originated on the parent body of the Vesta Family, although this claim is disputed. Others derive from unidentified asteroids. Two small groups of achondrites are special, as they are younger and do not appear to come from the asteroid belt. One of these groups comes from the Moon, and includes rocks similar to those brought back to Earth by Apollo and Luna programs. The other group is almost certainly from Mars and constitutes the only materials from other planets ever recovered by humans.  About 5% of meteorites that have been seen to fall are iron meteorites composed of iron-nickel alloys, such as kamacite and/or taenite. Most iron meteorites are thought to come from the cores of planetesimals that were once molten. As with the Earth, the denser metal separated from silicate material and sank toward the center of the planetesimal, forming its core. After the planetesimal solidified, it broke up in a collision with another planetesimal. Due to the low abundance of iron meteorites in collection areas such as Antarctica, where most of the meteoric material that has fallen can be recovered, it is possible that the percentage of iron-meteorite falls is lower than 5%. This would be explained by a recovery bias; laypeople are more likely to notice and recover solid masses of metal than most other meteorite types. The abundance of iron meteorites relative to total Antarctic finds is 0.4%.  Stony-iron meteorites constitute the remaining 1%. They are a mixture of iron-nickel metal and silicate minerals. One type, called pallasites, is thought to have originated in the boundary zone above the core regions where iron meteorites originated. The other major type of stony-iron meteorites is the mesosiderites.  Tektites (from Greek "tektos", molten) are not themselves meteorites, but are rather natural glass objects up to a few centimeters in size that were formed—according to most scientists—by the impacts of large meteorites on Earth's surface. A few researchers have favored tektites originating from the Moon as volcanic ejecta, but this theory has lost much of its support over the last few decades.

Meteorite chemistry.

In March 2015, NASA scientists reported that, for the first time, complex organic compounds found in DNA and RNA, including uracil, cytosine and thymine, have been formed in the laboratory under outer space conditions, using starting chemicals, such as pyrimidine, found in meteorites. Pyrimidine and polycyclic aromatic hydrocarbons (PAHs) may have been formed in red giants or in interstellar dust and gas clouds, according to the scientists.  In January 2018, researchers found that 4.5 billion-year-old meteorites found on Earth contained liquid water along with prebiotic complex organic substances that may be ingredients for life.  In November 2019, scientists reported detecting sugar molecules in meteorites for the first time, including ribose, suggesting that chemical processes on asteroids can produce some organic compounds fundamental to life, and supporting the notion of an RNA world prior to a DNA-based origin of life on Earth.

Meteorite recovery.

Falls.

Most meteorite falls are recovered on the basis of eyewitness accounts of the fireball or the impact of the object on the ground, or both. Therefore, despite the fact that meteorites fall with virtually equal probability everywhere on Earth, verified meteorite falls tend to be concentrated in areas with high human population densities such as Europe, Japan, and northern India.  A small number of meteorite falls have been observed with automated cameras and recovered following calculation of the impact point. The first of these was the Přibram meteorite, which fell in Czechoslovakia (now the Czech Republic) in 1959. In this case, two cameras used to photograph meteors captured images of the fireball. The images were used both to determine the location of the stones on the ground and, more significantly, to calculate for the first time an accurate orbit for a recovered meteorite.  Following the Pribram fall, other nations established automated observing programs aimed at studying infalling meteorites. One of these was the "Prairie Network", operated by the Smithsonian Astrophysical Observatory from 1963 to 1975 in the midwestern US. This program also observed a meteorite fall, the "Lost City" chondrite, allowing its recovery and a calculation of its orbit. Another program in Canada, the Meteorite Observation and Recovery Project, ran from 1971 to 1985. It too recovered a single meteorite, "Innisfree", in 1977. Finally, observations by the European Fireball Network, a descendant of the original Czech program that recovered Pribram, led to the discovery and orbit calculations for the "Neuschwanstein" meteorite in 2002. NASA has an automated system that detects meteors and calculates the orbit, magnitude, ground track, and other parameters over the southeast USA, which often detects a number of events each night.

Finds.

Until the twentieth century, only a few hundred meteorite finds had ever been discovered. More than 80% of these were iron and stony-iron meteorites, which are easily distinguished from local rocks. To this day, few stony meteorites are reported each year that can be considered to be "accidental" finds. The reason there are now more than 30,000 meteorite finds in the world's collections started with the discovery by Harvey H. Nininger that meteorites are much more common on the surface of the Earth than was previously thought.

The Great Plains of the US.

Nininger's strategy was to search for meteorites in the Great Plains of the United States, where the land was largely cultivated and the soil contained few rocks. Between the late 1920s and the 1950s, he traveled across the region, educating local people about what meteorites looked like and what to do if they thought they had found one, for example, in the course of clearing a field. The result was the discovery of over 200 new meteorites, mostly stony types.  In the late 1960s, Roosevelt County, New Mexico in the Great Plains was found to be a particularly good place to find meteorites. After the discovery of a few meteorites in 1967, a public awareness campaign resulted in the finding of nearly 100 new specimens in the next few years, with many being by a single person, Ivan Wilson. In total, nearly 140 meteorites were found in the region since 1967. In the area of the finds, the ground was originally covered by a shallow, loose soil sitting atop a hardpan layer. During the dustbowl era, the loose soil was blown off, leaving any rocks and meteorites that were present stranded on the exposed surface.

Antarctica.

A few meteorites were found in Antarctica between 1912 and 1964. In 1969, the 10th Japanese Antarctic Research Expedition found nine meteorites on a blue ice field near the Yamato Mountains. With this discovery, came the realization that movement of ice sheets might act to concentrate meteorites in certain areas. After a dozen other specimens were found in the same place in 1973, a Japanese expedition was launched in 1974 dedicated to the search for meteorites. This team recovered nearly 700 meteorites.  Shortly thereafter, the United States began its own program to search for Antarctic meteorites, operating along the Transantarctic Mountains on the other side of the continent: the Antarctic Search for Meteorites (ANSMET) program. European teams, starting with a consortium called "EUROMET" in the 1990/91 season, and continuing with a program by the Italian Programma Nazionale di Ricerche in Antartide have also conducted systematic searches for Antarctic meteorites.  The Antarctic Scientific Exploration of China has conducted successful meteorite searches since 2000. A Korean program (KOREAMET) was launched in 2007 and has collected a few meteorites. The combined efforts of all of these expeditions have produced more than 23,000 classified meteorite specimens since 1974, with thousands more that have not yet been classified. For more information see the article by Harvey (2003).

Australia.

At about the same time as meteorite concentrations were being discovered in the cold desert of Antarctica, collectors discovered that many meteorites could also be found in the hot deserts of Australia. Several dozen meteorites had already been found in the Nullarbor region of Western and South Australia. Systematic searches between about 1971 and the present recovered more than 500 others, ~300 of which are currently well characterized. The meteorites can be found in this region because the land presents a flat, featureless, plain covered by limestone. In the extremely arid climate, there has been relatively little weathering or sedimentation on the surface for tens of thousands of years, allowing meteorites to accumulate without being buried or destroyed. The dark colored meteorites can then be recognized among the very different looking limestone pebbles and rocks.

The Sahara.

In 1986–87, a German team installing a network of seismic stations while prospecting for oil discovered about 65 meteorites on a flat, desert plain about southeast of Dirj (Daraj), Libya. A few years later, a desert enthusiast saw photographs of meteorites being recovered by scientists in Antarctica, and thought that he had seen similar occurrences in northern Africa. In 1989, he recovered about 100 meteorites from several distinct locations in Libya and Algeria. Over the next several years, he and others who followed found at least 400 more meteorites. The find locations were generally in regions known as regs or hamadas: flat, featureless areas covered only by small pebbles and minor amounts of sand. Dark-colored meteorites can be easily spotted in these places. In the case of several meteorite fields, such as Dar el Gani, Dhofar, and others, favorable light-colored geology consisting of basic rocks (clays, dolomites, and limestones) makes meteorites particularly easy to identify.  Although meteorites had been sold commercially and collected by hobbyists for many decades, up to the time of the Saharan finds of the late 1980s and early 1990s, most meteorites were deposited in or purchased by museums and similar institutions where they were exhibited and made available for scientific research. The sudden availability of large numbers of meteorites that could be found with relative ease in places that were readily accessible (especially compared to Antarctica), led to a rapid rise in commercial collection of meteorites. This process was accelerated when, in 1997, meteorites coming from both the Moon and Mars were found in Libya. By the late 1990s, private meteorite-collecting expeditions had been launched throughout the Sahara. Specimens of the meteorites recovered in this way are still deposited in research collections, but most of the material is sold to private collectors. These expeditions have now brought the total number of well-described meteorites found in Algeria and Libya to more than 500.

Northwest Africa.

Meteorite markets came into existence in the late 1990s, especially in Morocco. This trade was driven by Western commercialization and an increasing number of collectors. The meteorites were supplied by nomads and local people who combed the deserts looking for specimens to sell. Many thousands of meteorites have been distributed in this way, most of which lack any information about how, when, or where they were discovered. These are the so-called "Northwest Africa" meteorites. When they get classified, they are named "Northwest Africa" (abbreviated NWA) followed by a number. It is generally accepted that NWA meteorites originate in Morocco, Algeria, Western Sahara, Mali, and possibly even further afield. Nearly all of these meteorites leave Africa through Morocco. Scores of important meteorites, including Lunar and Martian ones, have been discovered and made available to science via this route. A few of the more notable meteorites recovered include Tissint and Northwest Africa 7034. Tissint was the first witnessed Martian meteorite fall in over fifty years; NWA 7034 is the oldest meteorite known to come from Mars, and is a unique water-bearing regolith breccia.

Arabian Peninsula.

In 1999, meteorite hunters discovered that the desert in southern and central Oman were also favorable for the collection of many specimens. The gravel plains in the Dhofar and Al Wusta regions of Oman, south of the sandy deserts of the Rub' al Khali, had yielded about 5,000 meteorites as of mid-2009. Included among these are a large number of lunar and Martian meteorites, making Oman a particularly important area both for scientists and collectors. Early expeditions to Oman were mainly done by commercial meteorite dealers, however international teams of Omani and European scientists have also now collected specimens.  The recovery of meteorites from Oman is currently prohibited by national law, but a number of international hunters continue to remove specimens now deemed national treasures. This new law provoked a small international incident, as its implementation preceded any public notification of such a law, resulting in the prolonged imprisonment of a large group of meteorite hunters, primarily from Russia, but whose party also consisted of members from the US as well as several other European countries.

The American Southwest.

Beginning in the mid-1960s, amateur meteorite hunters began scouring the arid areas of the southwestern United States. To date, thousands of meteorites have been recovered from the Mojave, Sonoran, Great Basin, and Chihuahuan Deserts, with many being recovered on dry lake beds. Significant finds include the three tonne Old Woman meteorite, currently on display at the Desert Discovery Center in Barstow, California, and the Franconia and Gold Basin meteorite strewn fields; hundreds of kilograms of meteorites have been recovered from each. A number of finds from the American Southwest have been submitted with false find locations, as many finders think it is unwise to publicly share that information for fear of confiscation by the federal government and competition with other hunters at published find sites. Several of the meteorites found recently are currently on display in the Griffith Observatory in Los Angeles, and at UCLA's Meteorite Gallery.

Meteorites in history.

Meteorite falls may have been the source of cultish worship. The cult in the Temple of Artemis at Ephesus, one of the Seven Wonders of the Ancient World, possibly originated with the observation and recovery of a meteorite that was understood by contemporaries to have fallen to the earth from Jupiter, the principal Roman deity. There are reports that a sacred stone was enshrined at the temple that may have been a meteorite. The Black Stone set into the wall of the Kaaba has often been presumed to be a meteorite, but the little available evidence for this is inconclusive. Although the use of the metal found in meteorites is also recorded in myths of many countries and cultures where the celestial source was often acknowledged, scientific documentation only began in the last few centuries.  The oldest known iron artifacts are nine small beads hammered from meteoritic iron. They were found in northern Egypt and have been securely dated to 3200 BC.  In the 1970s, a stone meteorite was uncovered during an archaeological dig at Danebury Iron Age hillfort, Danebury England. It was found deposited part way down in an Iron Age pit (c. 1200 BC). Since it must have been deliberately placed there, this could indicate one of the first (known) human finds of a meteorite in Europe.  Some Native Americans treated meteorites as ceremonial objects. In 1915, a iron meteorite was found in a Sinagua (c. 1100–1200 AD) burial cyst near Camp Verde, Arizona, respectfully wrapped in a feather cloth. A small pallasite was found in a pottery jar in an old burial found at Pojoaque Pueblo, New Mexico. Nininger reports several other such instances, in the Southwest US and elsewhere, such as the discovery of Native American beads of meteoric iron found in Hopewell burial mounds, and the discovery of the Winona meteorite in a Native American stone-walled crypt. Indigenous peoples often prized iron-nickel meteorites as an easy, if limited, source of iron metal. For example, the Inuit used chips of the Cape York meteorite to form cutting edges for tools and spear tips.  Two of the oldest recorded meteorite falls in Europe are the Elbogen (1400) and Ensisheim (1492) meteorites. The German physicist, Ernst Florens Chladni, was the first to publish (in 1794) the idea that meteorites might be rocks that originated not from Earth, but from space. His booklet was ""On the Origin of the Iron Masses Found by Pallas and Others Similar to it, and on Some Associated Natural Phenomena"". In this he compiled all available data on several meteorite finds and falls concluded that they must have their origins in outer space. The scientific community of the time responded with resistance and mockery. It took nearly ten years before a general acceptance of the origin of meteorites was achieved through the work of the French scientist Jean-Baptiste Biot and the British chemist, Edward Howard. Biot's study, initiated by the French Academy of Sciences, was compelled by a fall of thousands of meteorites on 26 April 1803 from the skies of L'Aigle, France.  One of the leading theories for the cause of the Cretaceous–Paleogene extinction event that included the dinosaurs is a large meteorite impact. The Chicxulub Crater has been identified as the site of this impact. There has been a lively scientific debate as to whether other major extinctions, including the ones at the end of the Permian and Triassic periods might also have been the result of large impact events, but the evidence is much less compelling than for the end Cretaceous extinction.

Fatalities.

Throughout history, many first- and second-hand reports of meteorites falling on and killing both humans and other animals abound. One example is from 1490 AD in China, which purportedly killed thousands of people. John Lewis has compiled some of these reports, and summarizes, "No one in recorded history has ever been killed by a meteorite in the presence of a meteoriticist and a medical doctor" and "reviewers who make sweeping negative conclusions usually do not cite any of the primary publications in which the eyewitnesses describe their experiences, and give no evidence of having read them". In 1888, a meteorite reportedly killed a man and left another paralyzed in Sulaymaniyah, Iraq, according to the Ottoman Empire governor, Sultan Abdul Hamid II.  The most well-known reported fatality from a meteorite impact is that of a dog killed by the fall of the Nakhla meteorite in Egypt, in 1911. This meteorite fall was identified in the 1980s as Martian in origin. A meteorite known as Valera (Venezuela 1972, see Meteorite fall) reportedly hit and killed a cow upon impact, nearly dividing the animal in two, but the fall was not reported for several decades and no evidence was preserved. There are similar unsubstantiated reports of a horse being struck and killed by a stone of the New Concord fall. Shortly after the 2007 Carancas impact event, there were rumors of a goat and lama being killed by the impact. Again, these claims could not be verified.  The first known modern case of a human hit by a space rock occurred on 30 November 1954 in Sylacauga, Alabama. A stone chondrite crashed through a roof and hit Ann Hodges in her living room after it bounced off her radio. She was badly bruised. The Hodges meteorite, or Sylacauga meteorite, is currently on exhibit at the Alabama Museum of Natural History.  Another claim was put forth by a young boy who stated that he had been hit by a small (~3-gram) stone of the Mbale meteorite fall from Uganda, and who stood to gain nothing from this assertion. The stone reportedly fell through banana leaves before striking the boy on the head, causing little to no pain, as it was small enough to have been slowed by both friction with the atmosphere as well as that with banana leaves, before striking the boy.  Several persons have since claimed to have been struck by "meteorites" but no verifiable meteorites have resulted.

Meteorite weathering.

Most meteorites date from the oldest times in the solar system and are by far the oldest material available on the planet. Despite their age, they are fairly vulnerable to terrestrial environment: water, salt, and oxygen attack the meteorites as soon they reach the ground.  The terrestrial alteration of meteorites is called weathering. In order to quantify the degree of alteration that a meteorite experienced, several qualitative weathering indices have been applied to Antarctic and desertic samples.  The most known weathering scale, used for ordinary chondrites, ranges from W0 (pristine state) to W6 (heavy alteration).

Fossil meteorites.

"Fossil" meteorites are sometimes discovered by geologists. They represent the deeply weathered remains of meteorites that fell to Earth in the remote past and were preserved in sedimentary deposits sufficiently well that they can be recognized through mineralogical and geochemical studies. One limestone quarry in Sweden has produced an anomalously large number (more than a hundred) fossil meteorites from the Ordovician, nearly all of which are deeply weathered L-chondrites that still resemble the original meteorite under a petrographic microscope, but which have had their original material almost entirely replaced by terrestrial secondary mineralization. The extraterrestrial provenance was demonstrated in part through isotopic analysis of relict spinel grains, a mineral that is common in meteorites, is insoluble in water, and is able to persist chemically unchanged in the terrestrial weathering environment. One of these fossil meteorites, dubbed Österplana 065, appears to represent a distinct type of meteorite that is "extinct" in the sense that it is no longer falling to Earth, the parent body having already been completely depleted from reservoir of Near Earth Objects.  Acfer 049, a meteorite discovered in Algeria in 1990, was shown in 2019 to have ice fossils inside it – the first direct evidence of water ice in the composition of asteroids.

Notable meteorites.

Apart from meteorites fallen onto the Earth, two tiny fragments of asteroids were found among the samples collected on the Moon; these were the Bench Crater meteorite (Apollo 12, 1969) and the Hadley Rille meteorite (Apollo 15, 1971).

A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a fireball, also known as a shooting star or falling star; astronomers call the brightest examples "bolides". Once it settles on the larger body's surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater.

Meteorit je menší kosmické těleso (původně meteoroid), které díky příznivým podmínkám dopadlo na povrch Země (popřípadě jiné planety). Pokud středně velký nebo větší meteoroid vletí do zemské atmosféry, vidíme světelný jev, který nazýváme meteor, v případě větší jasnosti bolid. Rychlost meteorů v atmosféře dosahuje obvykle od 11 do 72 km/s. Pro malá tělesa se používá označení mikrometeorit.


Early life.

Feynman was born on May 11, 1918, in Queens, New York City, to Lucille, a homemaker, and Melville Arthur Feynman, a sales manager originally from Minsk in Belarus (then part of the Russian Empire). Feynman was a late talker, and did not speak until after his third birthday. As an adult he spoke with a New York accent strong enough to be perceived as an affectation or exaggeration—so much so that his friends Wolfgang Pauli and Hans Bethe once commented that Feynman spoke like a "bum". The young Feynman was heavily influenced by his father, who encouraged him to ask questions to challenge orthodox thinking, and who was always ready to teach Feynman something new. From his mother, he gained the sense of humor that he had throughout his life. As a child, he had a talent for engineering, maintained an experimental laboratory in his home, and delighted in repairing radios. When he was in grade school, he created a home burglar alarm system while his parents were out for the day running errands.  When Richard was five his mother gave birth to a younger brother, Henry Phillips, who died at age four weeks. Four years later, Richard's sister Joan was born and the family moved to Far Rockaway, Queens. Though separated by nine years, Joan and Richard were close, and they both shared a curiosity about the world. Though their mother thought women lacked the capacity to understand such things, Richard encouraged Joan's interest in astronomy, and Joan eventually became an astrophysicist.

Religion.

Feynman's parents were both from Jewish families but not religious, and by his youth, Feynman described himself as an "avowed atheist". Many years later, in a letter to Tina Levitan, declining a request for information for her book on Jewish Nobel Prize winners, he stated, "To select, for approbation the peculiar elements that come from some supposedly Jewish heredity is to open the door to all kinds of nonsense on racial theory", adding, "at thirteen I was

Education.

Feynman attended Far Rockaway High School, a school in Far Rockaway, Queens, which was also attended by fellow Nobel laureates Burton Richter and Baruch Samuel Blumberg. Upon starting high school, Feynman was quickly promoted into a higher math class. An IQ test administered in high school estimated his IQ at 125—high but "merely respectable", according to biographer James Gleick. His sister Joan did better, allowing her to claim that she was smarter. Years later he declined to join Mensa International, saying that his IQ was too low. Physicist Steve Hsu stated of the test:  When Feynman was 15, he taught himself trigonometry, advanced algebra, infinite series, analytic geometry, and both differential and integral calculus. Before entering college, he was experimenting with and deriving mathematical topics such as the half-derivative using his own notation. He created special symbols for logarithm, sine, cosine and tangent functions so they did not look like three variables multiplied together, and for the derivative, to remove the temptation of canceling out the formula_1's. A member of the Arista Honor Society, in his last year in high school he won the New York University Math Championship. His habit of direct characterization sometimes rattled more conventional thinkers; for example, one of his questions, when learning feline anatomy, was "Do you have a map of the cat?" (referring to an anatomical chart).  Feynman applied to Columbia University but was not accepted because of their quota for the number of Jews admitted. Instead, he attended the Massachusetts Institute of Technology, where he joined the Pi Lambda Phi fraternity. Although he originally majored in mathematics, he later switched to electrical engineering, as he considered mathematics to be too abstract. Noticing that he "had gone too far", he then switched to physics, which he claimed was "somewhere in between". As an undergraduate, he published two papers

Manhattan Project.

In 1941, with World War II raging in Europe but the United States not yet at war, Feynman spent the summer working on ballistics problems at the Frankford Arsenal in Pennsylvania. After the attack on Pearl Harbor had brought the United States into the war, Feynman was recruited by Robert R. Wilson, who was working on means to produce enriched uranium for use in an atomic bomb, as part of what would become the Manhattan Project. At the time, Feynman had not earned a graduate degree. Wilson's team at Princeton was working on a device called an isotron, intended to electromagnetically separate uranium-235 from uranium-238. This was done in a quite different manner from that used by the calutron that was under development by a team under Wilson's former mentor, Ernest O. Lawrence, at the Radiation Laboratory of the University of California. On paper, the isotron was many times more efficient than the calutron, but Feynman and Paul Olum struggled to determine whether or not it was practical. Ultimately, on Lawrence's recommendation, the isotron project was abandoned.  At this juncture, in early 1943, Robert Oppenheimer was establishing the Los Alamos Laboratory, a secret laboratory on a mesa in New Mexico where atomic bombs would be designed and built. An offer was made to the Princeton team to be redeployed there. "Like a bunch of professional soldiers," Wilson later recalled, "we signed up, en masse, to go to Los Alamos." Like many other young physicists, Feynman soon fell under the spell of the charismatic Oppenheimer, who telephoned Feynman long distance from Chicago to inform him that he had found a sanatorium in Albuquerque, New Mexico, for Arline. They were among the first to depart for New Mexico, leaving on a train on March 28, 1943. The railroad supplied Arline with a wheelchair, and Feynman paid extra for a private room for her.  At Los Alamos, Feynman was assigned to Hans Bethe's Theoretical (T) Division, and impressed Bethe enough to be made a group leader. He and Bethe developed the Bethe–Feynman formula for calculating the yield of a fission bomb, which built upon previous work by Robert Serber. As a junior physicist, he was not central to the project. He administered the computation group of human computers in the theoretical division. With Stanley Frankel and Nicholas Metropolis, he assisted in establishing a system for using IBM punched cards for computation. He invented a new method of computing logarithms that he later used

Cornell.

Feynman nominally held an appointment at the University of Wisconsin–Madison as an assistant professor of physics, but was on unpaid leave during his involvement in the Manhattan Project. In 1945, he received a letter from Dean Mark Ingraham of the College of Letters and Science requesting his return to the university to teach in the coming academic year. His appointment was not extended when he did not commit to returning. In a talk given there several years later, Feynman quipped, "It's great to be back at the only university that ever had the good sense to fire me."  As early as October 30, 1943, Bethe had written to the chairman of the physics department of his university, Cornell, to recommend that Feynman be hired. On February 28, 1944, this was endorsed by Robert Bacher, also from Cornell, and one of the most senior scientists at Los Alamos. This led to an offer being made in August 1944, which Feynman accepted. Oppenheimer had also hoped to recruit Feynman to the University of California, but the head of the physics department, Raymond T. Birge, was reluctant. He made Feynman an offer in May 1945, but Feynman turned it down. Cornell matched its salary offer of $3,900 per annum. Feynman became one of the first of the Los Alamos Laboratory's group leaders to depart, leaving for Ithaca, New York, in October 1945.  Because Feynman was no longer working at the Los Alamos Laboratory, he was no longer exempt from the draft. At his induction, physical Army psychiatrists diagnosed Feynman as suffering from a mental illness and the Army gave him a 4-F exemption on mental grounds. His father died suddenly on October 8, 1946, and Feynman suffered from depression. On October 17, 1946, he wrote a letter to Arline, expressing his deep love and heartbreak. The letter was sealed and only opened after his death. "Please excuse my not mailing this," the letter concluded, "but I don't know your new address." Unable to focus on research problems, Feynman began tackling physics problems, not for utility, but for self-satisfaction. One of these involved analyzing the physics of a twirling, nutating disk as it is moving through the air, inspired by an incident in the cafeteria at Cornell when someone tossed a dinner plate in the air. He read the work of Sir William Rowan Hamilton on quaternions, and attempted unsuccessfully to use them to formulate a relativistic theory of electrons. His work during this period, which used equations of rotation to express various spinning speeds, ultimately proved important to his Nobel Prize–winning work, yet because he felt burned out and had turned his attention to less immediately practical problems, he was surprised by the offers of professorships from other renowned universities, including the Institute for Advanced Study, the University of California, Los Angeles, and the University of California, Berkeley. Feynman was not the only frustrated theoretical physicist in the early post-war years. Quantum electrodynamics suffered from infinite

Caltech years.

Personal and political life.

Feynman spent several weeks in Rio de Janeiro in July 1949. That year, the Soviet Union detonated its first atomic bomb, generating anti-communist hysteria. Fuchs was arrested as a Soviet spy in 1950 and the FBI questioned Bethe about Feynman's loyalty. Physicist David Bohm was arrested on December 4, 1950 and emigrated to Brazil in October 1951. Because of the fears of a nuclear war, a girlfriend told Feynman that he should also consider moving to South America. He had a sabbatical coming for 1951–52, and elected to spend it in Brazil, where he gave courses at the Centro Brasileiro de Pesquisas Físicas. In Brazil, Feynman was impressed with "samba" music, and learned to play a metal percussion instrument, the "frigideira". He was an

Physics.

At Caltech, Feynman investigated the physics of the superfluidity of supercooled liquid helium, where helium seems to display a complete lack of viscosity when flowing. Feynman provided a quantum-mechanical explanation for the Soviet physicist Lev Landau's theory of superfluidity. Applying the Schrödinger equation to the question showed that the superfluid was displaying quantum mechanical behavior observable on a macroscopic scale. This helped with the problem of superconductivity, but the solution eluded Feynman. It was solved with the BCS theory of superconductivity, proposed by John Bardeen, Leon Neil Cooper, and John Robert Schrieffer in 1957. Feynman, inspired by a desire to quantize the Wheeler–Feynman absorber theory of electrodynamics, laid the groundwork for the path integral formulation and

Pedagogy.

In the early 1960s, Feynman acceded to a request to "spruce up" the teaching of undergraduates at Caltech. After three years devoted to the task, he produced a series of lectures that later became "The Feynman Lectures on Physics". He wanted a picture of a drumhead sprinkled with powder to show the modes of vibration at the beginning of the book. Concerned over the connections to drugs and rock and roll that could be made from the image, the publishers changed the cover to plain red, though they included a picture of him playing drums in the foreword. "The Feynman Lectures on Physics" occupied two physicists, Robert B. Leighton and Matthew

"Surely You're Joking, Mr. Feynman!".

In the 1960s, Feynman began thinking of writing an autobiography, and he began granting interviews to historians. In the 1980s, working with Ralph Leighton (Robert Leighton's son), he recorded chapters on audio tape that Ralph transcribed. The book was published in 1985 as "Surely You're Joking, Mr. Feynman!" and became a best-seller.  Gell-Mann was upset by Feynman's account in the book of the weak interaction work, and threatened to sue, resulting in a correction being inserted in later editions. This incident was just the latest provocation in decades of bad feeling between the two scientists. Gell-Mann often expressed frustration at the attention Feynman received; he remarked: "[Feynman] was a great scientist, but he spent a great deal of his effort generating anecdotes about himself."  Feynman has been criticized

"Challenger" disaster.

When invited to join the Rogers Commission, which investigated the "Challenger" disaster, Feynman was hesitant. The nation's capital, he told his wife, was "a great big world of mystery to me, with tremendous forces". But she convinced him to go, saying he might discover something others overlooked. Because Feynman did not balk at blaming NASA for the disaster, he clashed with the politically savvy commission chairman William Rogers, a former Secretary of State. During a break in one hearing, Rogers told commission member Neil Armstrong, "Feynman is becoming a pain in the ass." During a televised hearing, Feynman demonstrated that the material used in the shuttle's O-rings became less resilient in cold weather by compressing a sample of the material in a clamp and immersing it in ice-cold water. The commission ultimately

Recognition and awards.

The first public recognition of Feynman's work came in 1954, when Lewis Strauss, the chairman of the Atomic Energy Commission (AEC) notified him that he had won the Albert Einstein Award, which was worth $15,000 and came with a gold medal. Because of Strauss's actions in stripping Oppenheimer of his security clearance, Feynman was reluctant to accept the award, but Isidor Isaac Rabi cautioned him: "You should never turn a man's generosity as a

Death.

In 1978, Feynman sought medical treatment for abdominal pains and was diagnosed with liposarcoma, a rare form of cancer. Surgeons removed a tumor the size of a football that had crushed one kidney and his spleen. Further operations were performed in October 1986 and October 1987. He was again hospitalized at the UCLA Medical Center on February 3, 1988. A ruptured duodenal ulcer caused kidney failure, and he declined to undergo the dialysis that might have prolonged his life for a few months. Watched over by his wife Gweneth, sister Joan, and cousin Frances Lewine, he died on February 15, 1988,

Popular legacy.

Aspects of Feynman's life have been portrayed in various media. Feynman was portrayed by Matthew Broderick in the 1996 biopic "Infinity". Actor Alan Alda commissioned playwright Peter Parnell to write a two-character play about a fictional day in the life of Feynman set two years before Feynman's death. The play, "QED", premiered at the Mark Taper Forum in Los Angeles in 2001 and was later presented at the Vivian Beaumont Theater on Broadway, with both presentations starring Alda as Richard Feynman. Real Time Opera premiered its opera "Feynman" at the Norfolk (CT) Chamber Music Festival in June 2005. In 2011, Feynman was the subject of a biographical graphic novel entitled simply "Feynman", written by Jim Ottaviani and illustrated by Leland Myrick. In 2013, Feynman's role on the Rogers Commission was dramatised by the BBC in "The Challenger" (US title: "The Challenger Disaster"), with William Hurt playing Feynman. In the 2016 book, "Idea Makers: Personal Perspectives on the Lives & Ideas of Some Notable People", it states that one

Bibliography.

Textbooks and lecture notes.

"The Feynman Lectures on Physics" is perhaps his most accessible work for anyone with an interest in physics, compiled from lectures to Caltech undergraduates in 1961–1964. As news of the lectures' lucidity grew, professional physicists and graduate students began to drop in to

Richard Phillips Feynman, ForMemRS (; May 11, 1918 – February 15, 1988) was an American theoretical physicist, known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of the superfluidity of supercooled liquid helium, as well as his work in particle physics for which he proposed the parton model. For contributions to the development of quantum electrodynamics, Feynman received the Nobel Prize in Physics in 1965 jointly with Julian Schwinger and Shin'ichirō Tomonaga.

Richard Phillips Feynman, čtěte [ - ričrd fajnmen] (11. května 1918 New York – 15. února 1988 Los Angeles, Kalifornie) byl americký teoretický fyzik, známý především pro svou práci na formulaci kvantové mechaniky pomocí dráhových integrálů, teorii kvantové elektrodynamiky, fyzice supratekutosti hélia při teplotě blízké absolutní nule, a fyzice částic pro kterou navrhl partonový model. Za své přispění k rozvoji kvantové elektrodynamiky obdržel v roce 1965 společně s Julianem Schwingerem a Shin'ichirō Tomonagou Nobelovu cenu za fyziku. Feynman je autorem velmi používané grafické reprezentace matematických výrazů popisujících chování subatomárních částic, které později vešly ve známost jako Feynmanovy diagramy. Podílel se na výrobě atomové bomby za druhé světové války a byl součástí Rogerovy komise pro vyšetřování katastrofy raketoplánu Challenger. Mimo práci na poli teoretické fyziky stál u vzniku odvětví zabývající se kvantovými počítači a zavádění konceptu nanotechnologie. Feynman byl také známým popularizátorem vědy. V roce 1999 ho britský časopis Physics World zařadil do top desítky největších fyziků všech dob.


Ancestry.

Hitler's father Alois Hitler Sr. (1837–1903) was the illegitimate child of Maria Anna Schicklgruber. The baptismal register did not show the name of his father, and Alois initially bore his mother's surname "Schicklgruber". In 1842, Johann Georg Hiedler married Alois's mother Maria Anna. Alois was brought up in the family of Hiedler's brother, Johann Nepomuk Hiedler. In 1876, Alois was legitimated and the baptismal record received an annotation made

Early years.

Childhood and education.

Adolf Hitler was born on 20 April 1889 in Braunau am Inn, a town in Austria-Hungary (in present-day Austria), close to the border with the German Empire. He was the fourth of six children born to Alois Hitler and his third wife, Klara Pölzl. Three of Hitler's siblings—Gustav, Ida, and Otto—died in infancy. Also living in the household were Alois's children from his second marriage: Alois Jr. (born 1882) and Angela (born 1883). When Hitler was three, the family moved to Passau, Germany. There he acquired the distinctive lower Bavarian dialect, rather than Austrian German, which marked his speech throughout his life. The family returned to Austria and settled in Leonding in 1894, and in June 1895 Alois retired to Hafeld, near Lambach, where he farmed and kept bees. Hitler attended "Volksschule" (a state-owned primary school) in nearby Fischlham.  The move to Hafeld coincided with the onset of intense father-son conflicts caused by Hitler's refusal to conform to the strict discipline of his school. His father beat him, although his mother tried to protect him. Alois Hitler's farming efforts at Hafeld ended in failure, and in 1897 the family moved to Lambach. The eight-year-old Hitler took singing lessons,

Early adulthood in Vienna and Munich.

In 1907 Hitler left Linz to live and study fine art in Vienna, financed by orphan's benefits and support from his mother. He applied for admission to the Academy of Fine Arts Vienna but was rejected twice. The director suggested Hitler should apply to the School of Architecture, but he lacked the necessary academic credentials because he had not finished secondary school.  On 21 December 1907, his mother died of breast cancer at the age of 47, when he himself was 18. In 1909 Hitler ran out of money and was forced to live a bohemian life in homeless shelters and a men's dormitory. He earned money as a casual labourer and by painting and selling watercolours of Vienna's sights. During his time in Vienna, he pursued a growing passion for architecture and music, attending ten performances of "Lohengrin", his favourite Wagner opera. It was in Vienna that Hitler first became exposed to racist rhetoric. Populists such as mayor Karl Lueger exploited the climate of virulent anti-Semitism and occasionally espoused German nationalist notions for political effect. German nationalism

World War I.

In August 1914, at the outbreak of World War I, Hitler was living in Munich and voluntarily enlisted in the Bavarian Army. According to a 1924 report by the Bavarian authorities, allowing Hitler to serve was almost certainly an administrative error, since as an Austrian citizen, he should have been returned to Austria. Posted to the Bavarian Reserve Infantry Regiment 16 (1st Company of the List Regiment), he served as a dispatch runner on the Western Front in France and Belgium, spending nearly half his time at the regimental headquarters in Fournes-en-Weppes, well behind the front lines. He was present at the First Battle of Ypres, the Battle of the Somme, the Battle of Arras, and the Battle of Passchendaele, and was wounded at the Somme. He was decorated for bravery, receiving the Iron Cross, Second Class, in 1914. On a recommendation by Lieutenant Hugo Gutmann, Hitler's Jewish superior, he received the Iron Cross, First Class on 4 August 1918, a decoration rarely awarded to one of Hitler's "Gefreiter" rank. He received the Black Wound Badge on 18 May 1918.  During his

Entry into politics.

After World War I, Hitler returned to Munich. Without formal education or career prospects, he remained in the army. In July 1919 he was appointed "Verbindungsmann" (intelligence agent) of an "Aufklärungskommando" (reconnaissance unit) of the "Reichswehr", assigned to influence other soldiers and to infiltrate the German Workers' Party (DAP). At a DAP meeting on 12 September 1919, Party Chairman Anton Drexler was impressed with Hitler's oratorical skills. He gave him a copy of his pamphlet "My Political Awakening", which contained anti-Semitic, nationalist, anti-capitalist, and anti-Marxist ideas. On the orders of his army superiors, Hitler applied to join the party, and within a week was accepted as party member 555 (the party began counting membership at 500 to give the impression they were a much larger party).  Around this time, Hitler made his earliest known recorded statement about the Jews in a letter (now known as the Gemlich letter) dated 16 September 1919 to Adolf Gemlich about the Jewish question. In the letter, Hitler argues that the aim of the government "must unshakably be the removal of the Jews altogether".  At the DAP, Hitler met Dietrich Eckart, one of the party's founders and a member of the occult Thule Society. Eckart became Hitler's mentor, exchanging ideas with him and introducing him to a wide range of Munich society. To increase its appeal, the DAP changed its name to the "Nationalsozialistische Deutsche Arbeiterpartei" (National Socialist German Workers Party; NSDAP). Hitler designed the party's banner of a swastika in a white circle on a red background.  Hitler was discharged from the army on 31 March 1920 and began working full-time for the NSDAP. The party headquarters was in Munich, a hotbed of anti-government German nationalists determined to crush Marxism and undermine the Weimar Republic. In February 1921—already highly effective at crowd manipulation—he spoke to a crowd of over 6,000. To publicise the meeting, two truckloads of party supporters drove around Munich waving swastika flags and distributing leaflets. Hitler soon gained notoriety for his rowdy polemic speeches against the Treaty of Versailles, rival politicians, and especially against Marxists and Jews. In June 1921, while Hitler and Eckart were on a fundraising trip to Berlin, a mutiny broke out within the NSDAP in Munich. Members of its executive committee wanted to merge with the rival German Socialist Party (DSP). Hitler returned to Munich on 11 July and angrily tendered his resignation. The committee members realised that the resignation of their leading public figure and speaker would mean the end of the party. Hitler announced he would rejoin on the condition that he would replace Drexler as party chairman, and that the party headquarters would remain in Munich. The committee agreed, and he rejoined the party on 26 July as member 3,680. Hitler continued to face some opposition within the NSDAP: Opponents of Hitler in the leadership had Hermann Esser expelled from the party, and they printed 3,000 copies of a pamphlet attacking Hitler as a traitor to the party. In the following days, Hitler spoke to several packed houses and defended himself and Esser, to thunderous applause. His strategy proved successful, and at a special party congress on 29 July, he was granted absolute powers as party chairman, replacing Drexler, by a vote of 533to1.  Hitler's vitriolic beer hall speeches began attracting regular audiences. A demagogue, he became adept at using populist themes, including the use of scapegoats, who were blamed for his listeners' economic hardships. Hitler used personal magnetism and an understanding of crowd psychology to his advantage while engaged in public speaking. Historians have noted the hypnotic effect of his rhetoric on large audiences, and of his eyes in small groups. Algis Budrys recalled the crowd noise and behaviour when Hitler appeared in a 1936 parade; some in the audience writhed and rolled on the ground or experienced fecal incontinence. Alfons Heck, a former member of the Hitler Youth, recalled a similar experience: Early followers included Rudolf Hess, former air force ace Hermann Göring, and army captain Ernst Röhm. Röhm became head of the Nazis' paramilitary organisation, the "Sturmabteilung" (SA, "Stormtroopers"), which protected meetings and attacked political opponents. A critical influence on Hitler's thinking during this period was the "Aufbau Vereinigung", a conspiratorial group of White Russian exiles and early National Socialists. The group, financed with funds channelled from wealthy industrialists, introduced Hitler to the idea of a Jewish conspiracy, linking international finance with Bolshevism.  The programme of the NSDAP, known colloquially as the "Nazi Party", was laid out in their 25-point programme on 24 February 1920. This did not represent a coherent ideology, but was a conglomeration of received ideas which had currency in the "völkisch" Pan-Germanic movement, such as ultranationalism, opposition to the Treaty of Versailles, distrust of capitalism, as well as some socialist ideas. For Hitler, though, the most important aspect of it was its strong anti-Semitic stance. He also perceived the programme as primarily a basis for propaganda and for attracting people to the party.

Rise to power.

Brüning administration.

The Great Depression provided a political opportunity for Hitler. Germans were ambivalent about the parliamentary republic, which faced challenges from right- and left-wing extremists. The moderate political parties were increasingly unable to stem the tide of extremism, and the German referendum of 1929 helped to elevate Nazi ideology. The elections of September 1930 resulted in the break-up of a grand coalition and its replacement with a minority cabinet. Its leader, chancellor Heinrich Brüning of the Centre Party, governed through emergency decrees from President Paul von Hindenburg. Governance by decree became the new norm and paved the way for authoritarian forms of government. The NSDAP rose from obscurity to win 18.3 per cent of the vote and 107 parliamentary seats in the 1930 election, becoming the second-largest party in parliament. Hitler made a prominent appearance at the trial of two Reichswehr officers, Lieutenants Richard Scheringer and Hanns Ludin, in late 1930. Both were charged with membership in the NSDAP, at that time illegal for Reichswehr personnel. The prosecution argued that the NSDAP was an extremist party, prompting defence lawyer Hans Frank to call on Hitler to testify.

Appointment as chancellor.

The absence of an effective government prompted two influential politicians, Franz von Papen and Alfred Hugenberg, along with several other industrialists and businessmen, to write a letter to Hindenburg. The signers urged Hindenburg to appoint Hitler as leader of a government "independent from parliamentary parties", which could turn into a movement that would "enrapture millions of people".  Hindenburg reluctantly agreed to appoint Hitler as chancellor after two further

Reichstag fire and March elections.

As chancellor, Hitler worked against attempts by the NSDAP's opponents to build a majority government. Because of the political stalemate, he asked Hindenburg to again dissolve the Reichstag, and elections were scheduled for early March. On 27 February 1933, the Reichstag building was set on fire. Göring blamed a communist plot, because Dutch communist Marinus van der Lubbe was found in incriminating circumstances inside the burning building. According to Kershaw, the consensus of nearly all historians is that van der Lubbe actually set the fire. Others, including William L. Shirer and Alan Bullock, are

Day of Potsdam and the Enabling Act.

On 21 March 1933, the new Reichstag was constituted with an opening ceremony at the Garrison Church in Potsdam. This "Day of Potsdam" was held to demonstrate unity between the Nazi movement and the old Prussian elite and military. Hitler appeared in a morning coat and humbly greeted Hindenburg.  To achieve full political control despite not having an absolute majority in parliament, Hitler's government brought the "Ermächtigungsgesetz" (Enabling Act) to a vote in the newly elected Reichstag. The Act—officially titled the "Gesetz zur Behebung der Not von Volk und Reich" ("Law to Remedy the Distress of People and Reich")—gave Hitler's cabinet the power to enact laws without the consent of the Reichstag for four years. These laws could (with certain exceptions) deviate

Dictatorship.

Having achieved full control over the legislative and executive branches of government, Hitler and his allies began to suppress the remaining opposition. The Social Democratic Party was banned and its assets seized. While many trade union delegates were in Berlin for May Day activities, SA stormtroopers demolished union offices around the country. On 2 May 1933 all trade unions were forced to dissolve and their leaders were arrested. Some were sent to concentration camps. The German Labour Front was formed as an umbrella organisation to represent all workers, administrators, and company owners, thus reflecting the concept of national socialism in the spirit of Hitler's "Volksgemeinschaft" ("people's community"). By the end

Nazi Germany.

Economy and culture.

In August 1934, Hitler appointed "Reichsbank" President Hjalmar Schacht as Minister of Economics, and in the following year, as Plenipotentiary for War Economy in charge of preparing the economy for war. Reconstruction and rearmament were financed through Mefo bills, printing money, and seizing the assets of people arrested as enemies of the State, including Jews. Unemployment fell from six million in 1932 to one million in 1936. Hitler oversaw one of the largest infrastructure improvement campaigns in German history, leading to the construction

Rearmament and new alliances.

In a meeting with German military leaders on 3 February 1933, Hitler spoke of "conquest for "Lebensraum" in the East and its ruthless Germanisation" as his ultimate foreign policy objectives. In March, Prince Bernhard Wilhelm von Bülow, secretary at the Auswärtiges Amt (Foreign Office), issued a statement of major foreign policy aims: "Anschluss" with Austria, the restoration of Germany's national borders of 1914, rejection of military restrictions under the Treaty of Versailles, the return of the former German colonies in Africa, and a German zone of influence in Eastern Europe. Hitler found Bülow's goals to be too modest. In speeches during this

World War II.

Early diplomatic successes.

Alliance with Japan.

In February 1938, on the advice of his newly appointed foreign minister, the strongly pro-Japanese Joachim von Ribbentrop, Hitler ended the Sino-German alliance with the Republic of China to instead enter into an alliance with the more modern and powerful Empire of

Austria and Czechoslovakia.

On 12 March 1938, Hitler announced the unification of Austria with Nazi Germany in the "Anschluss". Hitler then turned his attention to the ethnic German population of the Sudetenland region of Czechoslovakia. On 28–29 March 1938, Hitler held a series of secret meetings in Berlin with Konrad Henlein of the Sudeten German Party, the largest of the ethnic German parties of the Sudetenland. The men agreed that Henlein would demand increased autonomy for Sudeten Germans from the Czechoslovakian government, thus providing a pretext for German military action against Czechoslovakia. In April 1938 Henlein told the foreign minister of Hungary that "whatever the Czech government might offer, he would always raise still higher demands... he wanted to sabotage an understanding by any means because this was the only method to blow up Czechoslovakia quickly". In private, Hitler considered the Sudeten issue unimportant; his real intention was a war of conquest against Czechoslovakia.  In April Hitler ordered the OKW to prepare for "Fall Grün" (Case Green), the code name for an invasion of Czechoslovakia. As a result of intense French and British diplomatic pressure, on 5 September Czechoslovakian President Edvard Beneš unveiled the "Fourth Plan" for constitutional reorganisation

Start of World War II.

In private discussions in 1939, Hitler declared Britain the main enemy to be defeated and that Poland's obliteration was a necessary prelude for that goal. The eastern flank would be secured and land would be added to Germany's "Lebensraum". Offended by the British "guarantee" on 31 March 1939 of Polish independence, he said, "I shall brew them a devil's drink". In a speech in Wilhelmshaven for the launch of the battleship on 1 April, he threatened to denounce the Anglo-German Naval Agreement if the British continued to guarantee Polish independence, which he perceived as an "encirclement" policy. Poland was to either become a German satellite state or it would be neutralised in order to secure the Reich's eastern flank and prevent a possible British blockade. Hitler initially favoured the idea of a satellite state, but upon its rejection by the Polish government, he decided to invade and made this the main foreign policy goal of 1939. On 3 April, Hitler ordered the military to prepare for "Fall Weiss" ("Case White"), the plan for invading Poland on 25 August. In a Reichstag speech on 28 April, he renounced both the Anglo-German

Path to defeat.

On 22 June 1941, contravening the Molotov–Ribbentrop Pact of 1939, over three million Axis troops attacked the Soviet Union. This offensive (codenamed Operation Barbarossa) was intended to destroy the Soviet Union and seize its natural resources for subsequent aggression against the Western powers. The invasion conquered a huge area, including the Baltic republics, Belarus, and West Ukraine. By early August, Axis troops had advanced and won the Battle of Smolensk. Hitler ordered Army Group Centre to temporarily halt its advance to Moscow and divert its Panzer groups to aid in the encirclement of Leningrad and Kiev.

Defeat and death.

By late 1944, both the Red Army and the Western Allies were advancing into Germany. Recognising the strength and determination of the Red Army, Hitler decided to use his remaining mobile reserves against the American and British troops, which he perceived as far weaker. On 16 December, he launched the Ardennes Offensive to incite disunity among the Western Allies and perhaps convince them to join his fight against the Soviets. The offensive failed after some temporary successes. With much of Germany in ruins in January 1945, Hitler spoke on the radio: "However grave as the crisis may be at this moment, it will, despite everything, be mastered by our unalterable will." Acting on his view that Germany's military failures meant it had forfeited its right to

The Holocaust.

The Holocaust and Germany's war in the East were based on Hitler's long-standing view that the Jews were the enemy of the German people and that "Lebensraum" was needed for Germany's expansion. He focused on Eastern Europe for this expansion, aiming to defeat Poland and the Soviet Union and then removing or killing the Jews and Slavs. The "Generalplan Ost" (General Plan East) called for deporting the population of occupied Eastern Europe and the Soviet Union to West Siberia, for use as slave labour or to be murdered; the conquered territories were to be colonised by German or "Germanised" settlers. The goal was to implement this plan after the conquest of the Soviet Union, but when this failed, Hitler moved the plans forward. By January 1942, he had decided that the Jews, Slavs, and other deportees considered undesirable should be killed.  The genocide was organised and executed by Heinrich Himmler and Reinhard Heydrich. The records of the Wannsee Conference, held on 20 January 1942 and led by Heydrich, with fifteen senior Nazi officials participating, provide the clearest evidence of systematic planning for the Holocaust. On 22 February, Hitler was recorded saying, "we shall regain our health only by eliminating the Jews". Similarly, at a meeting in July 1941 with leading functionaries of the Eastern territories, Hitler said that the easiest way to quickly pacify the areas would be best achieved by "shooting everyone who even looks odd". Although no direct order from Hitler authorising the mass killings has surfaced, his public speeches, orders to his generals, and the diaries of Nazi officials demonstrate that he conceived and authorised the extermination of European Jewry. During the war, Hitler repeatedly stated his prophecy of 1939 was being fulfilled,

Leadership style.

Hitler ruled the NSDAP autocratically by asserting the "Führerprinzip" (leader principle). The principle relied on absolute obedience of all subordinates to their superiors; thus he viewed the government structure as a pyramid, with himself—the infallible leader—at the apex. Rank in the party was not determined by elections—positions were filled through appointment by those of higher rank, who demanded unquestioning obedience to the will of the leader. Hitler's leadership style was to give contradictory orders to his subordinates and to place them into positions where their duties and responsibilities overlapped with those of others, to have "the stronger one [do] the job". In this way, Hitler fostered distrust, competition, and infighting among his subordinates to consolidate and maximise his own power. His cabinet never met after 1938, and he discouraged his ministers from meeting independently. Hitler typically did not give written orders; instead he communicated verbally, or had them conveyed through his close associate, Martin Bormann. He entrusted Bormann with

Personal life.

Family.

Hitler created a public image as a celibate man without a domestic life, dedicated entirely to his political mission and the nation. He met his lover, Eva Braun, in 1929, and married her on 29 April 1945, one day before they both

Views on religion.

Hitler was born to a practising Catholic mother and an anticlerical father; after leaving home Hitler never again attended Mass or received the sacraments. Speer states that Hitler railed against the church to his political associates and though he never officially left it, he had no attachment to it. He adds that Hitler felt that in the absence of organised religion, people would turn to mysticism, which he considered regressive. According to Speer, Hitler believed that Japanese religious beliefs or Islam would have been a more suitable religion for Germans than Christianity, with its "meekness and flabbiness".  Historian John S. Conway states that Hitler was fundamentally opposed to the Christian churches. According to Bullock, Hitler did not believe in God, was anticlerical, and held Christian ethics in contempt because they contravened his preferred view

Health.

Researchers have variously suggested that Hitler suffered from irritable bowel syndrome, skin lesions, irregular heartbeat, coronary sclerosis, Parkinson's disease, syphilis, giant-cell arteritis, and tinnitus. In a report prepared for the OSS in 1943, Walter C. Langer of Harvard University described Hitler as a "neurotic psychopath". In his 1977 book "", historian Robert G. L. Waite proposes that he suffered from borderline personality disorder. Historians Henrik Eberle and Hans-Joachim Neumann consider that while he suffered from a number of illnesses including Parkinson's disease, Hitler did not experience pathological delusions and was always fully aware of, and therefore responsible for, his decisions. Theories about Hitler's medical condition are difficult to prove, and placing too much weight on them may have the effect of attributing many of the events and consequences of Nazi Germany to the possibly impaired physical health of one individual. Kershaw feels that it is better to take a broader view of German history by examining what social forces led to the Nazi dictatorship and its policies rather than to pursue narrow explanations for the Holocaust and World WarII based on only one person.  Sometime in the 1930s Hitler adopted a mainly vegetarian

Legacy.

Hitler's suicide was likened by contemporaries to a "spell" being broken. Public support for Hitler had collapsed by the time of his death and few Germans mourned his passing; Kershaw argues that most civilians and military personnel were too busy adjusting to the collapse of the country or fleeing from the fighting to take any interest. According to historian John Toland, National Socialism "burst like a bubble" without its leader.  Hitler's actions and Nazi ideology are almost universally regarded as gravely immoral; according to Kershaw, "Never in history has such ruination—physical and moral—been associated with the name of one man." Hitler's political programme brought about a world war, leaving behind a devastated and impoverished Eastern and Central Europe. Germany suffered wholesale destruction, characterised as "Stunde Null" (Zero Hour). Hitler's policies inflicted human suffering on an unprecedented scale; according to R. J. Rummel, the Nazi regime was responsible for the democidal killing of an estimated 19.3 million civilians and prisoners of war. In addition, 28.7million soldiers and civilians died as a result of military action in the European Theatre of World War II. The number of civilians killed during the Second World War was unprecedented in the history of warfare. Historians, philosophers, and politicians often use the word "evil" to describe the Nazi regime. Many European countries have criminalised both the promotion of Nazism and Holocaust denial.  Historian Friedrich Meinecke described Hitler as "one of the great examples of the singular and incalculable power of personality in historical life". English historian Hugh Trevor-Roper saw him as "among the 'terrible simplifiers' of history, the most systematic, the most historical, the most philosophical, and yet the coarsest, cruelest, least magnanimous conqueror the world has ever known". For the historian John M. Roberts, Hitler's defeat marked the end of a phase of European history dominated by Germany. In its place emerged the Cold War, a global confrontation between the Western Bloc, dominated by the United States and other NATO nations, and the Eastern Bloc, dominated by the Soviet Union. Historian Sebastian Haffner asserts that without Hitler and the displacement of the Jews, the modern nation state of Israel would not exist. He contends that without Hitler, the de-colonisation of former European spheres of influence would have been postponed. Further, Haffner claims that other than Alexander the Great, Hitler had a more significant impact than any other comparable historical figure, in that he too caused a wide range of worldwide changes in a relatively short time span.

In propaganda.

Hitler exploited documentary films and newsreels to inspire a cult of personality. He was involved and appeared

Adolf Hitler (; 20 April 1889 – 30 April 1945) was a German politician and leader of the Nazi Party ("Nationalsozialistische Deutsche Arbeiterpartei"; NSDAP). He rose to power as the chancellor of Germany in 1933 and then as "Führer" in 1934. During his dictatorship from 1933 to 1945, he initiated World War II in Europe by invading Poland on 1 September 1939. He was closely involved in military operations throughout the war and was central to the perpetration of the Holocaust.

Adolf Hitler (20. dubna 1889 Braunau am Inn – 30. dubna 1945 Berlín) byl německý nacistický politik rakouského původu, od roku 1933 do své smrti kancléř a diktátor nacistického Německa. Jako takzvaný Vůdce (německy "") byl odpovědný za zločiny nacistického režimu, zejména za vyvražďování Židů, Romů, Poláků a dalších Slovanů, a postižených. Jen při holocaustu bylo zavražděno na šest milionů Židů. Agresivní politikou zprvu dosahoval územní zisky a ústupky jiných států, roku 1939 však napadením Polska vyvolal druhou světovou válku, která si v Evropě vyžádala přibližně 40 milionů lidských životů. Ve válce Německo nakonec utrpělo drtivou porážku.