text stringlengths 151 4.06k |
|---|
By the end of May, drafts were formally presented. In mid-June, the main Tripartite negotiations started. The discussion was focused on potential guarantees to central and east European countries should a German aggression arise. The USSR proposed to consider that a political turn towards Germany by the Baltic states would constitute an "indirect aggression" towards the Soviet Union. Britain opposed such proposals, because they feared the Soviets' proposed language could justify a Soviet intervention in Finland and the Baltic states, or push those countries to seek closer relations with Germany. The discussion about a definition of "indirect aggression" became one of the sticking points between the parties, and by mid-July, the tripartite political negotiations effectively stalled, while the parties agreed to start negotiations on a military agreement, which the Soviets insisted must be entered into simultaneously with any political agreement. |
From April–July, Soviet and German officials made statements regarding the potential for the beginning of political negotiations, while no actual negotiations took place during that time period. The ensuing discussion of a potential political deal between Germany and the Soviet Union had to be channeled into the framework of economic negotiations between the two countries, because close military and diplomatic connections, as was the case before the mid-1930s, had afterward been largely severed. In May, Stalin replaced his Foreign Minister Maxim Litvinov, who was regarded as pro-western and who was also Jewish, with Vyacheslav Molotov, allowing the Soviet Union more latitude in discussions with more parties, not only with Britain and France. |
At the same time, British, French, and Soviet negotiators scheduled three-party talks on military matters to occur in Moscow in August 1939, aiming to define what the agreement would specify should be the reaction of the three powers to a German attack. The tripartite military talks, started in mid-August, hit a sticking point regarding the passage of Soviet troops through Poland if Germans attacked, and the parties waited as British and French officials overseas pressured Polish officials to agree to such terms. Polish officials refused to allow Soviet troops into Polish territory if Germany attacked; as Polish foreign minister Józef Beck pointed out, they feared that once the Red Army entered their territories, it might never leave. |
On August 19, the 1939 German–Soviet Commercial Agreement was finally signed. On 21 August, the Soviets suspended Tripartite military talks, citing other reasons. That same day, Stalin received assurance that Germany would approve secret protocols to the proposed non-aggression pact that would place half of Poland (border along the Vistula river), Latvia, Estonia, Finland, and Bessarabia in the Soviets' sphere of influence. That night, Stalin replied that the Soviets were willing to sign the pact and that he would receive Ribbentrop on 23 August. |
On 22 August, one day after the talks broke down with France and Britain, Moscow revealed that Ribbentrop would visit Stalin the next day. This happened while the Soviets were still negotiating with the British and French missions in Moscow. With the Western nations unwilling to accede to Soviet demands, Stalin instead entered a secret Nazi–Soviet pact. On 24 August a 10-year non-aggression pact was signed with provisions that included: consultation, arbitration if either party disagreed, neutrality if either went to war against a third power, no membership of a group "which is directly or indirectly aimed at the other". |
Most notably, there was also a secret protocol to the pact, revealed only after Germany's defeat in 1945, although hints about its provisions were leaked much earlier, e.g., to influence Lithuania. According to said protocol Romania, Poland, Lithuania, Latvia, Estonia and Finland were divided into German and Soviet "spheres of influence". In the north, Finland, Estonia and Latvia were assigned to the Soviet sphere. Poland was to be partitioned in the event of its "political rearrangement"—the areas east of the Pisa, Narev, Vistula and San rivers going to the Soviet Union while Germany would occupy the west. Lithuania, adjacent to East Prussia, would be in the German sphere of influence, although a second secret protocol agreed to in September 1939 reassigned the majority of Lithuania to the USSR. According to the secret protocol, Lithuania would be granted the city of Vilnius – its historical capital, which was under Polish control during the inter-war period. Another clause of the treaty was that Germany would not interfere with the Soviet Union's actions towards Bessarabia, then part of Romania; as the result, Bessarabia was joined to the Moldovan ASSR, and become the Moldovan SSR under control of Moscow. |
On 24 August, Pravda and Izvestia carried news of the non-secret portions of the Pact, complete with the now infamous front-page picture of Molotov signing the treaty, with a smiling Stalin looking on. The news was met with utter shock and surprise by government leaders and media worldwide, most of whom were aware only of the British–French–Soviet negotiations that had taken place for months. The Molotov–Ribbentrop Pact was received with shock by Nazi Germany's allies, notably Japan, by the Comintern and foreign communist parties, and by Jewish communities all around the world. So, that day, German diplomat Hans von Herwarth, whose grandmother was Jewish, informed Guido Relli, an Italian diplomat, and American chargé d'affaires Charles Bohlen on the secret protocol regarding vital interests in the countries' allotted "spheres of influence", without revealing the annexation rights for "territorial and political rearrangement". |
Soviet propaganda and representatives went to great lengths to minimize the importance of the fact that they had opposed and fought against the Nazis in various ways for a decade prior to signing the Pact. Upon signing the pact, Molotov tried to reassure the Germans of his good intentions by commenting to journalists that "fascism is a matter of taste". For its part, Nazi Germany also did a public volte-face regarding its virulent opposition to the Soviet Union, though Hitler still viewed an attack on the Soviet Union as "inevitable".[citation needed] |
The day after the Pact was signed, the French and British military negotiation delegation urgently requested a meeting with Soviet military negotiator Kliment Voroshilov. On August 25, Voroshilov told them "[i]n view of the changed political situation, no useful purpose can be served in continuing the conversation." That day, Hitler told the British ambassador to Berlin that the pact with the Soviets prevented Germany from facing a two front war, changing the strategic situation from that in World War I, and that Britain should accept his demands regarding Poland. |
On 1 September, Germany invaded Poland from the west. Within the first few days of the invasion, Germany began conducting massacres of Polish and Jewish civilians and POWs. These executions took place in over 30 towns and villages in the first month of German occupation. The Luftwaffe also took part by strafing fleeing civilian refugees on roads and carrying out a bombing campaign. The Soviet Union assisted German air forces by allowing them to use signals broadcast by the Soviet radio station at Minsk allegedly "for urgent aeronautical experiments". |
On 21 September, the Soviets and Germans signed a formal agreement coordinating military movements in Poland, including the "purging" of saboteurs. A joint German–Soviet parade was held in Lvov and Brest-Litovsk, while the countries commanders met in the latter location. Stalin had decided in August that he was going to liquidate the Polish state, and a German–Soviet meeting in September addressed the future structure of the "Polish region". Soviet authorities immediately started a campaign of Sovietization of the newly acquired areas. The Soviets organized staged elections, the result of which was to become a legitimization of Soviet annexation of eastern Poland. |
Eleven days after the Soviet invasion of the Polish Kresy, the secret protocol of the Molotov–Ribbentrop Pact was modified by the German–Soviet Treaty of Friendship, Cooperation and Demarcation,) allotting Germany a larger part of Poland and transferring Lithuania's territory (with the exception of left bank of river Scheschupe, the "Lithuanian Strip") from the envisioned German sphere to the Soviets. On 28 September 1939, the Soviet Union and German Reich issued a joint declaration in which they declared: |
After the Baltic states were forced to accept treaties, Stalin turned his sights on Finland, confident that Finnish capitulation could be attained without great effort. The Soviets demanded territories on the Karelian Isthmus, the islands of the Gulf of Finland and a military base near the Finnish capital Helsinki, which Finland rejected. The Soviets staged the shelling of Mainila and used it as a pretext to withdraw from the non-aggression pact. The Red Army attacked in November 1939. Simultaneously, Stalin set up a puppet government in the Finnish Democratic Republic.[clarification needed] The leader of the Leningrad Military District Andrei Zhdanov commissioned a celebratory piece from Dmitri Shostakovich, entitled "Suite on Finnish Themes" to be performed as the marching bands of the Red Army would be parading through Helsinki. After Finnish defenses surprisingly held out for over three months while inflicting stiff losses on Soviet forces, the Soviets settled for an interim peace. Finland ceded southeastern areas of Karelia (10% of Finnish territory), which resulted in approximately 422,000 Karelians (12% of Finland's population) losing their homes. Soviet official casualty counts in the war exceeded 200,000, although Soviet Premier Nikita Khrushchev later claimed the casualties may have been one million. |
In mid-June 1940, when international attention was focused on the German invasion of France, Soviet NKVD troops raided border posts in Lithuania, Estonia and Latvia. State administrations were liquidated and replaced by Soviet cadres, in which 34,250 Latvians, 75,000 Lithuanians and almost 60,000 Estonians were deported or killed. Elections were held with single pro-Soviet candidates listed for many positions, with resulting peoples assemblies immediately requesting admission into the USSR, which was granted by the Soviet Union. The USSR annexed the whole of Lithuania, including the Scheschupe area, which was to be given to Germany. |
Finally, on 26 June, four days after France sued for an armistice with the Third Reich, the Soviet Union issued an ultimatum demanding Bessarabia and, unexpectedly, Northern Bukovina from Romania. Two days later, the Romanians caved to the Soviet demands and the Soviets occupied the territory. The Hertza region was initially not requested by the USSR but was later occupied by force after the Romanians agreed to the initial Soviet demands. The subsequent waves of deportations began in Bessarabia and Northern Bukovina. |
Elimination of Polish elites and intelligentia was part of Generalplan Ost. The Intelligenzaktion, a plan to eliminate the Polish intelligentsia, Poland's 'leadership class', took place soon after the German invasion of Poland, lasting from fall of 1939 till spring of 1940. As the result of this operation in 10 regional actions about 60,000 Polish nobles, teachers, social workers, priests, judges and political activists were killed. It was continued in May 1940 when Germany launched AB-Aktion, More than 16,000 members of the intelligentsia were murdered in Operation Tannenberg alone. |
Although Germany used forced labourers in most occupied countries, Poles and other Slavs were viewed as inferior by Nazi propaganda, thus, better suited for such duties. Between 1 and 2.5 million Polish citizens were transported to the Reich for forced labour, against their will. All Polish males were required to perform forced labour. While ethnic Poles were subject to selective persecution, all ethnic Jews were targeted by the Reich. In the winter of 1939–40, about 100,000 Jews were thus deported to Poland. They were initially gathered into massive urban ghettos, such as 380,000 held in the Warsaw Ghetto, where large numbers died under the harsh conditions therein, including 43,000 in the Warsaw Ghetto alone. Poles and ethnic Jews were imprisoned in nearly every camp of the extensive concentration camp system in German-occupied Poland and the Reich. In Auschwitz, which began operating on 14 June 1940, 1.1 million people died. |
On 10 January 1941, Germany and the Soviet Union signed an agreement settling several ongoing issues. Secret protocols in the new agreement modified the "Secret Additional Protocols" of the German–Soviet Boundary and Friendship Treaty, ceding the Lithuanian Strip to the Soviet Union in exchange for 7.5 million dollars (31.5 million Reichsmark). The agreement formally set the border between Germany and the Soviet Union between the Igorka river and the Baltic Sea. It also extended trade regulation of the 1940 German–Soviet Commercial Agreement until August 1, 1942, increased deliveries above the levels of year one of that agreement, settled trading rights in the Baltics and Bessarabia, calculated the compensation for German property interests in the Baltic States now occupied by the Soviets and other issues. It also covered the migration to Germany within two and a half months of ethnic Germans and German citizens in Soviet-held Baltic territories, and the migration to the Soviet Union of Baltic and "White Russian" "nationals" in German-held territories. |
Before the pact's announcement, Communists in the West denied that such a treaty would be signed. Future member of the Hollywood Ten Herbert Biberman denounced rumors as "Fascist propaganda". Earl Browder, head of the Communist Party USA, stated that "there is as much chance of agreement as of Earl Browder being elected president of the Chamber of Commerce." Beginning in September 1939, the Soviet Comintern suspended all anti-Nazi and anti-fascist propaganda, explaining that the war in Europe was a matter of capitalist states attacking each other for imperialist purposes. Western Communists acted accordingly; while before they supported protecting collective security, now they denounced Britain and France going to war. |
When anti-German demonstrations erupted in Prague, Czechoslovakia, the Comintern ordered the Czech Communist Party to employ all of its strength to paralyze "chauvinist elements." Moscow soon forced the Communist Parties of France and Great Britain to adopt an anti-war position. On 7 September, Stalin called Georgi Dimitrov,[clarification needed] and the latter sketched a new Comintern line on the war. The new line—which stated that the war was unjust and imperialist—was approved by the secretariat of the Communist International on 9 September. Thus, the various western Communist parties now had to oppose the war, and to vote against war credits. Although the French Communists had unanimously voted in Parliament for war credits on 2 September and on 19 September declared their "unshakeable will" to defend the country, on 27 September the Comintern formally instructed the party to condemn the war as imperialist. By 1 October the French Communists advocated listening to German peace proposals, and Communist leader Maurice Thorez deserted from the French Army on 4 October and fled to Russia. Other Communists also deserted from the army. |
The Communist Party of Germany featured similar attitudes. In Die Welt, a communist newspaper published in Stockholm[e] the exiled communist leader Walter Ulbricht opposed the allies (Britain representing "the most reactionary force in the world") and argued: "The German government declared itself ready for friendly relations with the Soviet Union, whereas the English–French war bloc desires a war against the socialist Soviet Union. The Soviet people and the working people of Germany have an interest in preventing the English war plan." |
When a joint German–Soviet peace initiative was rejected by Britain and France on 28 September 1939, Soviet foreign policy became critical of the Allies and more pro-German in turn. During the fifth session of the Supreme Soviet on 31 October 1939 Molotov analysed the international situation thus giving the direction for Communist propaganda. According to Molotov Germany had a legitimate interest in regaining its position as a great power and the Allies had started an aggressive war in order to maintain the Versailles system. |
Molotov declared in his report entitled "On the Foreign Policy of the Soviet Union" (31 October 1939) held on the fifth (extraordinary) session of the Supreme Soviet, that the Western "ruling circles" disguise their intentions with the pretext of defending democracy against Hitlerism, declaring "their aim in war with Germany is nothing more, nothing less than extermination of Hitlerism. [...] There is absolutely no justification for this kind of war. The ideology of Hitlerism, just like any other ideological system, can be accepted or rejected, this is a matter of political views. But everyone grasps, that an ideology can not be exterminated by force, must not be finished off with a war." |
Germany and the Soviet Union entered an intricate trade pact on February 11, 1940, that was over four times larger than the one the two countries had signed in August 1939. The trade pact helped Germany to surmount a British blockade of Germany. In the first year, Germany received one million tons of cereals, half a million tons of wheat, 900,000 tons of oil, 100,000 tons of cotton, 500,000 tons of phosphates and considerable amounts of other vital raw materials, along with the transit of one million tons of soybeans from Manchuria.[citation needed] These and other supplies were being transported through Soviet and occupied Polish territories. The Soviets were to receive a naval cruiser, the plans to the battleship Bismarck, heavy naval guns, other naval gear and thirty of Germany's latest warplanes, including the Me-109 and Me-110 fighters and Ju-88 bomber. The Soviets would also receive oil and electric equipment, locomotives, turbines, generators, diesel engines, ships, machine tools and samples of German artillery, tanks, explosives, chemical-warfare equipment and other items. |
The Soviets also helped Germany to avoid British naval blockades by providing a submarine base, Basis Nord, in the northern Soviet Union near Murmansk. This also provided a refueling and maintenance location, and a takeoff point for raids and attacks on shipping. In addition, the Soviets provided Germany with access to the Northern Sea Route for both cargo ships and raiders (though only the commerce raider Komet used the route before the German invasion), which forced Britain to protect sea lanes in both the Atlantic and the Pacific. |
The Finnish and Baltic invasions began a deterioration of relations between the Soviets and Germany. Stalin's invasions were a severe irritant to Berlin, as the intent to accomplish these was not communicated to the Germans beforehand, and prompted concern that Stalin was seeking to form an anti-German bloc. Molotov's reassurances to the Germans, and the Germans' mistrust, intensified. On June 16, as the Soviets invaded Lithuania, but before they had invaded Latvia and Estonia, Ribbentrop instructed his staff "to submit a report as soon as possible as to whether in the Baltic States a tendency to seek support from the Reich can be observed or whether an attempt was made to form a bloc." |
In August 1940, the Soviet Union briefly suspended its deliveries under their commercial agreement after their relations were strained following disagreement over policy in Romania, the Soviet war with Finland, Germany falling behind in its deliveries of goods under the pact and with Stalin worried that Hitler's war with the West might end quickly after France signed an armistice. The suspension created significant resource problems for Germany. By the end of August, relations improved again as the countries had redrawn the Hungarian and Romanian borders, settled some Bulgarian claims and Stalin was again convinced that Germany would face a long war in the west with Britain's improvement in its air battle with Germany and the execution of an agreement between the United States and Britain regarding destroyers and bases. However, in late August, Germany arranged its own occupation of Romania, targeting oil fields. The move raised tensions with the Soviets, who responded that Germany was supposed to have consulted with the Soviet Union under Article III of the Molotov–Ribbentrop Pact. |
After Germany entered a Tripartite Pact with Japan and Italy, Ribbentrop wrote to Stalin, inviting Molotov to Berlin for negotiations aimed to create a 'continental bloc' of Germany, Italy, Japan and the USSR that would oppose Britain and the USA. Stalin sent Molotov to Berlin to negotiate the terms for the Soviet Union to join the Axis and potentially enjoy the spoils of the pact. After negotiations during November 1940 on where to extend the USSR's sphere of influence, Hitler broke off talks and continued planning for the eventual attempts to invade the Soviet Union. |
In an effort to demonstrate peaceful intentions toward Germany, on 13 April 1941, the Soviets signed a neutrality pact with Axis power Japan. While Stalin had little faith in Japan's commitment to neutrality, he felt that the pact was important for its political symbolism, to reinforce a public affection for Germany. Stalin felt that there was a growing split in German circles about whether Germany should initiate a war with the Soviet Union. Stalin did not know that Hitler had been secretly discussing an invasion of the Soviet Union since summer 1940, and that Hitler had ordered his military in late 1940 to prepare for war in the east regardless of the parties' talks of a potential Soviet entry as a fourth Axis Power. |
Nazi Germany terminated the Molotov–Ribbentrop Pact at 03:15 on 22 June 1941 by launching a massive attack on the Soviet positions in eastern Poland which marked the beginning of the invasion of the Soviet Union known as Operation Barbarossa. Stalin had ignored several warnings that Germany was likely to invade, and ordered no 'full-scale' mobilization of forces although the mobilization was ongoing. After the launch of the invasion, the territories gained by the Soviet Union as a result of the Molotov–Ribbentrop Pact were lost in a matter of weeks. Within six months, the Soviet military had suffered 4.3 million casualties, and Germany had captured three million Soviet prisoners. The lucrative export of Soviet raw materials to Nazi Germany over the course of the Nazi–Soviet economic relations (1934–41) continued uninterrupted until the outbreak of hostilities. The Soviet exports in several key areas enabled Germany to maintain its stocks of rubber and grain from the first day of the invasion until October 1941. |
The German original of the secret protocols was presumably destroyed in the bombing of Germany, but in late 1943, Ribbentrop had ordered that the most secret records of the German Foreign Office from 1933 on, amounting to some 9,800 pages, be microfilmed. When the various departments of the Foreign Office in Berlin were evacuated to Thuringia at the end of the war, Karl von Loesch, a civil servant who had worked for the chief interpreter Paul Otto Schmidt, was entrusted with these microfilm copies. He eventually received orders to destroy the secret documents but decided to bury the metal container with the microfilms as a personal insurance for his future well-being. In May 1945, von Loesch approached the British Lt. Col. Robert C. Thomson with the request to transmit a personal letter to Duncan Sandys, Churchill's son-in-law. In the letter, von Loesch revealed that he had knowledge of the documents' whereabouts but expected preferential treatment in return. Colonel Thomson and his American counterpart Ralph Collins agreed to transfer von Loesch to Marburg in the American zone if he would produce the microfilms. The microfilms contained a copy of the Non-Aggression Treaty as well as the Secret Protocol. Both documents were discovered as part of the microfilmed records in August 1945 by the State Department employee Wendell B. Blancke, head of a special unit called "Exploitation German Archives" (EGA). |
The treaty was published in the United States for the first time by the St. Louis Post-Dispatch on May 22, 1946, in Britain by the Manchester Guardian. It was also part of an official State Department publication, Nazi–Soviet Relations 1939–1941, edited by Raymond J. Sontag and James S. Beddie in January 1948. The decision to publish the key documents on German–Soviet relations, including the treaty and protocol, had been taken already in spring 1947. Sontag and Beddie prepared the collection throughout the summer of 1947. In November 1947, President Truman personally approved the publication but it was held back in view of the Foreign Ministers Conference in London scheduled for December. Since negotiations at that conference did not prove constructive from an American point of view, the document edition was sent to press. The documents made headlines worldwide. State Department officials counted it as a success: "The Soviet Government was caught flat-footed in what was the first effective blow from our side in a clear-cut propaganda war." |
In response to the publication of the secret protocols and other secret German–Soviet relations documents in the State Department edition Nazi–Soviet Relations (1948), Stalin published Falsifiers of History, which included the claim that, during the Pact's operation, Stalin rejected Hitler's claim to share in a division of the world, without mentioning the Soviet offer to join the Axis. That version persisted, without exception, in historical studies, official accounts, memoirs and textbooks published in the Soviet Union until the Soviet Union's dissolution. |
For decades, it was the official policy of the Soviet Union to deny the existence of the secret protocol to the Soviet–German Pact. At the behest of Mikhail Gorbachev, Alexander Nikolaevich Yakovlev headed a commission investigating the existence of such a protocol. In December 1989, the commission concluded that the protocol had existed and revealed its findings to the Congress of People's Deputies of the Soviet Union. As a result, the Congress passed the declaration confirming the existence of the secret protocols, condemning and denouncing them. Both successor-states of the pact parties have declared the secret protocols to be invalid from the moment they were signed. The Federal Republic of Germany declared this on September 1, 1989 and the Soviet Union on December 24, 1989, following an examination of the microfilmed copy of the German originals. |
Regarding the timing of German rapprochement, many historians agree that the dismissal of Maxim Litvinov, whose Jewish ethnicity was viewed unfavorably by Nazi Germany, removed an obstacle to negotiations with Germany. Stalin immediately directed Molotov to "purge the ministry of Jews." Given Litvinov's prior attempts to create an anti-fascist coalition, association with the doctrine of collective security with France and Britain, and pro-Western orientation by the standards of the Kremlin, his dismissal indicated the existence of a Soviet option of rapprochement with Germany.[f] Likewise, Molotov's appointment served as a signal to Germany that the USSR was open to offers. The dismissal also signaled to France and Britain the existence of a potential negotiation option with Germany. One British official wrote that Litvinov's disappearance also meant the loss of an admirable technician or shock-absorber, while Molotov's "modus operandi" was "more truly Bolshevik than diplomatic or cosmopolitan." Carr argued that the Soviet Union's replacement of Foreign Minister Litvinov with Molotov on May 3, 1939 indicated not an irrevocable shift towards alignment with Germany, but rather was Stalin's way of engaging in hard bargaining with the British and the French by appointing a proverbial hard man, namely Molotov, to the Foreign Commissariat. Historian Albert Resis stated that the Litvinov dismissal gave the Soviets freedom to pursue faster-paced German negotiations, but that they did not abandon British–French talks. Derek Watson argued that Molotov could get the best deal with Britain and France because he was not encumbered with the baggage of collective security and could negotiate with Germany. Geoffrey Roberts argued that Litvinov's dismissal helped the Soviets with British–French talks, because Litvinov doubted or maybe even opposed such discussions. |
Edward Hallett Carr, a frequent defender of Soviet policy, stated: "In return for 'non-intervention' Stalin secured a breathing space of immunity from German attack."[page needed] According to Carr, the "bastion" created by means of the Pact, "was and could only be, a line of defense against potential German attack."[page needed] According to Carr, an important advantage was that "if Soviet Russia had eventually to fight Hitler, the Western Powers would already be involved."[page needed] However, during the last decades, this view has been disputed. Historian Werner Maser stated that "the claim that the Soviet Union was at the time threatened by Hitler, as Stalin supposed ... is a legend, to whose creators Stalin himself belonged. In Maser's view, "neither Germany nor Japan were in a situation [of] invading the USSR even with the least perspective [sic] of success," and this could not have been unknown to Stalin. Carr further stated that, for a long time, the primary motive of Stalin's sudden change of course was assumed to be the fear of German aggressive intentions. |
Some critics of Stalin's policy, such as the popular writer Viktor Suvorov, claim that Stalin's primary motive for signing the Soviet–German non-aggression treaty was his calculation that such a pact could result in a conflict between the capitalist countries of Western Europe.[citation needed] This idea is supported by Albert L. Weeks.[page needed] Claims by Suvorov that Stalin planned to invade Germany in 1941 are debated by historians with, for example, David Glantz opposing such claims, while Mikhail Meltyukhov supports them.[citation needed] The authors of The Black Book of Communism consider the pact a crime against peace and a "conspiracy to conduct war of aggression." |
A capacitor (originally known as a condenser) is a passive two-terminal electrical component used to store electrical energy temporarily in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors (plates) separated by a dielectric (i.e. an insulator that can store energy by becoming polarized). The conductors can be thin films, foils or sintered beads of metal or conductive electrolyte, etc. The nonconducting dielectric acts to increase the capacitor's charge capacity. Materials commonly used as dielectrics include glass, ceramic, plastic film, air, vacuum, paper, mica, and oxide layers. Capacitors are widely used as parts of electrical circuits in many common electrical devices. Unlike a resistor, an ideal capacitor does not dissipate energy. Instead, a capacitor stores energy in the form of an electrostatic field between its plates. |
When there is a potential difference across the conductors (e.g., when a capacitor is attached across a battery), an electric field develops across the dielectric, causing positive charge +Q to collect on one plate and negative charge −Q to collect on the other plate. If a battery has been attached to a capacitor for a sufficient amount of time, no current can flow through the capacitor. However, if a time-varying voltage is applied across the leads of the capacitor, a displacement current can flow. |
In October 1745, Ewald Georg von Kleist of Pomerania, Germany, found that charge could be stored by connecting a high-voltage electrostatic generator by a wire to a volume of water in a hand-held glass jar. Von Kleist's hand and the water acted as conductors, and the jar as a dielectric (although details of the mechanism were incorrectly identified at the time). Von Kleist found that touching the wire resulted in a powerful spark, much more painful than that obtained from an electrostatic machine. The following year, the Dutch physicist Pieter van Musschenbroek invented a similar capacitor, which was named the Leyden jar, after the University of Leiden where he worked. He also was impressed by the power of the shock he received, writing, "I would not take a second shock for the kingdom of France." |
Daniel Gralath was the first to combine several jars in parallel into a "battery" to increase the charge storage capacity. Benjamin Franklin investigated the Leyden jar and came to the conclusion that the charge was stored on the glass, not in the water as others had assumed. He also adopted the term "battery", (denoting the increasing of power with a row of similar units as in a battery of cannon), subsequently applied to clusters of electrochemical cells. Leyden jars were later made by coating the inside and outside of jars with metal foil, leaving a space at the mouth to prevent arcing between the foils.[citation needed] The earliest unit of capacitance was the jar, equivalent to about 1.11 nanofarads. |
Since the beginning of the study of electricity non conductive materials like glass, porcelain, paper and mica have been used as insulators. These materials some decades later were also well-suited for further use as the dielectric for the first capacitors. Paper capacitors made by sandwiching a strip of impregnated paper between strips of metal, and rolling the result into a cylinder were commonly used in the late 19century; their manufacture started in 1876, and they were used from the early 20th century as decoupling capacitors in telecommunications (telephony). |
Charles Pollak (born Karol Pollak), the inventor of the first electrolytic capacitors, found out that the oxide layer on an aluminum anode remained stable in a neutral or alkaline electrolyte, even when the power was switched off. In 1896 he filed a patent for an "Electric liquid capacitor with aluminum electrodes." Solid electrolyte tantalum capacitors were invented by Bell Laboratories in the early 1950s as a miniaturized and more reliable low-voltage support capacitor to complement their newly invented transistor. |
Last but not least the electric double-layer capacitor (now Supercapacitors) were invented. In 1957 H. Becker developed a "Low voltage electrolytic capacitor with porous carbon electrodes". He believed that the energy was stored as a charge in the carbon pores used in his capacitor as in the pores of the etched foils of electrolytic capacitors. Because the double layer mechanism was not known by him at the time, he wrote in the patent: "It is not known exactly what is taking place in the component if it is used for energy storage, but it leads to an extremely high capacity.". |
A capacitor consists of two conductors separated by a non-conductive region. The non-conductive region is called the dielectric. In simpler terms, the dielectric is just an electrical insulator. Examples of dielectric media are glass, air, paper, vacuum, and even a semiconductor depletion region chemically identical to the conductors. A capacitor is assumed to be self-contained and isolated, with no net electric charge and no influence from any external electric field. The conductors thus hold equal and opposite charges on their facing surfaces, and the dielectric develops an electric field. In SI units, a capacitance of one farad means that one coulomb of charge on each conductor causes a voltage of one volt across the device. |
The current I(t) through any component in an electric circuit is defined as the rate of flow of a charge Q(t) passing through it, but actual charges—electrons—cannot pass through the dielectric layer of a capacitor. Rather, one electron accumulates on the negative plate for each one that leaves the positive plate, resulting in an electron depletion and consequent positive charge on one electrode that is equal and opposite to the accumulated negative charge on the other. Thus the charge on the electrodes is equal to the integral of the current as well as proportional to the voltage, as discussed above. As with any antiderivative, a constant of integration is added to represent the initial voltage V(t0). This is the integral form of the capacitor equation: |
The simplest model capacitor consists of two thin parallel conductive plates separated by a dielectric with permittivity ε . This model may also be used to make qualitative predictions for other device geometries. The plates are considered to extend uniformly over an area A and a charge density ±ρ = ±Q/A exists on their surface. Assuming that the length and width of the plates are much greater than their separation d, the electric field near the centre of the device will be uniform with the magnitude E = ρ/ε. The voltage is defined as the line integral of the electric field between the plates |
The maximum energy is a function of dielectric volume, permittivity, and dielectric strength. Changing the plate area and the separation between the plates while maintaining the same volume causes no change of the maximum amount of energy that the capacitor can store, so long as the distance between plates remains much smaller than both the length and width of the plates. In addition, these equations assume that the electric field is entirely concentrated in the dielectric between the plates. In reality there are fringing fields outside the dielectric, for example between the sides of the capacitor plates, which will increase the effective capacitance of the capacitor. This is sometimes called parasitic capacitance. For some simple capacitor geometries this additional capacitance term can be calculated analytically. It becomes negligibly small when the ratios of plate width to separation and length to separation are large. |
Capacitors deviate from the ideal capacitor equation in a number of ways. Some of these, such as leakage current and parasitic effects are linear, or can be assumed to be linear, and can be dealt with by adding virtual components to the equivalent circuit of the capacitor. The usual methods of network analysis can then be applied. In other cases, such as with breakdown voltage, the effect is non-linear and normal (i.e., linear) network analysis cannot be used, the effect must be dealt with separately. There is yet another group, which may be linear but invalidate the assumption in the analysis that capacitance is a constant. Such an example is temperature dependence. Finally, combined parasitic effects such as inherent inductance, resistance, or dielectric losses can exhibit non-uniform behavior at variable frequencies of operation. |
For air dielectric capacitors the breakdown field strength is of the order 2 to 5 MV/m; for mica the breakdown is 100 to 300 MV/m; for oil, 15 to 25 MV/m; it can be much less when other materials are used for the dielectric. The dielectric is used in very thin layers and so absolute breakdown voltage of capacitors is limited. Typical ratings for capacitors used for general electronics applications range from a few volts to 1 kV. As the voltage increases, the dielectric must be thicker, making high-voltage capacitors larger per capacitance than those rated for lower voltages. The breakdown voltage is critically affected by factors such as the geometry of the capacitor conductive parts; sharp edges or points increase the electric field strength at that point and can lead to a local breakdown. Once this starts to happen, the breakdown quickly tracks through the dielectric until it reaches the opposite plate, leaving carbon behind and causing a short (or relatively low resistance) circuit. The results can be explosive as the short in the capacitor draws current from the surrounding circuitry and dissipates the energy. |
Ripple current is the AC component of an applied source (often a switched-mode power supply) whose frequency may be constant or varying. Ripple current causes heat to be generated within the capacitor due to the dielectric losses caused by the changing field strength together with the current flow across the slightly resistive supply lines or the electrolyte in the capacitor. The equivalent series resistance (ESR) is the amount of internal series resistance one would add to a perfect capacitor to model this. Some types of capacitors, primarily tantalum and aluminum electrolytic capacitors, as well as some film capacitors have a specified rating value for maximum ripple current. |
The capacitance of certain capacitors decreases as the component ages. In ceramic capacitors, this is caused by degradation of the dielectric. The type of dielectric, ambient operating and storage temperatures are the most significant aging factors, while the operating voltage has a smaller effect. The aging process may be reversed by heating the component above the Curie point. Aging is fastest near the beginning of life of the component, and the device stabilizes over time. Electrolytic capacitors age as the electrolyte evaporates. In contrast with ceramic capacitors, this occurs towards the end of life of the component. |
Capacitors, especially ceramic capacitors, and older designs such as paper capacitors, can absorb sound waves resulting in a microphonic effect. Vibration moves the plates, causing the capacitance to vary, in turn inducing AC current. Some dielectrics also generate piezoelectricity. The resulting interference is especially problematic in audio applications, potentially causing feedback or unintended recording. In the reverse microphonic effect, the varying electric field between the capacitor plates exerts a physical force, moving them as a speaker. This can generate audible sound, but drains energy and stresses the dielectric and the electrolyte, if any. |
In DC circuits and pulsed circuits, current and voltage reversal are affected by the damping of the system. Voltage reversal is encountered in RLC circuits that are under-damped. The current and voltage reverse direction, forming a harmonic oscillator between the inductance and capacitance. The current and voltage will tend to oscillate and may reverse direction several times, with each peak being lower than the previous, until the system reaches an equilibrium. This is often referred to as ringing. In comparison, critically damped or over-damped systems usually do not experience a voltage reversal. Reversal is also encountered in AC circuits, where the peak current will be equal in each direction. |
For maximum life, capacitors usually need to be able to handle the maximum amount of reversal that a system will experience. An AC circuit will experience 100% voltage reversal, while under-damped DC circuits will experience less than 100%. Reversal creates excess electric fields in the dielectric, causes excess heating of both the dielectric and the conductors, and can dramatically shorten the life expectancy of the capacitor. Reversal ratings will often affect the design considerations for the capacitor, from the choice of dielectric materials and voltage ratings to the types of internal connections used. |
Capacitors made with any type of dielectric material will show some level of "dielectric absorption" or "soakage". On discharging a capacitor and disconnecting it, after a short time it may develop a voltage due to hysteresis in the dielectric. This effect can be objectionable in applications such as precision sample and hold circuits or timing circuits. The level of absorption depends on many factors, from design considerations to charging time, since the absorption is a time-dependent process. However, the primary factor is the type of dielectric material. Capacitors such as tantalum electrolytic or polysulfone film exhibit very high absorption, while polystyrene or Teflon allow very small levels of absorption. In some capacitors where dangerous voltages and energies exist, such as in flashtubes, television sets, and defibrillators, the dielectric absorption can recharge the capacitor to hazardous voltages after it has been shorted or discharged. Any capacitor containing over 10 joules of energy is generally considered hazardous, while 50 joules or higher is potentially lethal. A capacitor may regain anywhere from 0.01 to 20% of its original charge over a period of several minutes, allowing a seemingly safe capacitor to become surprisingly dangerous. |
Leakage is equivalent to a resistor in parallel with the capacitor. Constant exposure to heat can cause dielectric breakdown and excessive leakage, a problem often seen in older vacuum tube circuits, particularly where oiled paper and foil capacitors were used. In many vacuum tube circuits, interstage coupling capacitors are used to conduct a varying signal from the plate of one tube to the grid circuit of the next stage. A leaky capacitor can cause the grid circuit voltage to be raised from its normal bias setting, causing excessive current or signal distortion in the downstream tube. In power amplifiers this can cause the plates to glow red, or current limiting resistors to overheat, even fail. Similar considerations apply to component fabricated solid-state (transistor) amplifiers, but owing to lower heat production and the use of modern polyester dielectric barriers this once-common problem has become relatively rare. |
Most types of capacitor include a dielectric spacer, which increases their capacitance. These dielectrics are most often insulators. However, low capacitance devices are available with a vacuum between their plates, which allows extremely high voltage operation and low losses. Variable capacitors with their plates open to the atmosphere were commonly used in radio tuning circuits. Later designs use polymer foil dielectric between the moving and stationary plates, with no significant air space between them. |
Several solid dielectrics are available, including paper, plastic, glass, mica and ceramic materials. Paper was used extensively in older devices and offers relatively high voltage performance. However, it is susceptible to water absorption, and has been largely replaced by plastic film capacitors. Plastics offer better stability and ageing performance, which makes them useful in timer circuits, although they may be limited to low operating temperatures and frequencies. Ceramic capacitors are generally small, cheap and useful for high frequency applications, although their capacitance varies strongly with voltage and they age poorly. They are broadly categorized as class 1 dielectrics, which have predictable variation of capacitance with temperature or class 2 dielectrics, which can operate at higher voltage. Glass and mica capacitors are extremely reliable, stable and tolerant to high temperatures and voltages, but are too expensive for most mainstream applications. Electrolytic capacitors and supercapacitors are used to store small and larger amounts of energy, respectively, ceramic capacitors are often used in resonators, and parasitic capacitance occurs in circuits wherever the simple conductor-insulator-conductor structure is formed unintentionally by the configuration of the circuit layout. |
Electrolytic capacitors use an aluminum or tantalum plate with an oxide dielectric layer. The second electrode is a liquid electrolyte, connected to the circuit by another foil plate. Electrolytic capacitors offer very high capacitance but suffer from poor tolerances, high instability, gradual loss of capacitance especially when subjected to heat, and high leakage current. Poor quality capacitors may leak electrolyte, which is harmful to printed circuit boards. The conductivity of the electrolyte drops at low temperatures, which increases equivalent series resistance. While widely used for power-supply conditioning, poor high-frequency characteristics make them unsuitable for many applications. Electrolytic capacitors will self-degrade if unused for a period (around a year), and when full power is applied may short circuit, permanently damaging the capacitor and usually blowing a fuse or causing failure of rectifier diodes (for instance, in older equipment, arcing in rectifier tubes). They can be restored before use (and damage) by gradually applying the operating voltage, often done on antique vacuum tube equipment over a period of 30 minutes by using a variable transformer to supply AC power. Unfortunately, the use of this technique may be less satisfactory for some solid state equipment, which may be damaged by operation below its normal power range, requiring that the power supply first be isolated from the consuming circuits. Such remedies may not be applicable to modern high-frequency power supplies as these produce full output voltage even with reduced input. |
Several other types of capacitor are available for specialist applications. Supercapacitors store large amounts of energy. Supercapacitors made from carbon aerogel, carbon nanotubes, or highly porous electrode materials, offer extremely high capacitance (up to 5 kF as of 2010[update]) and can be used in some applications instead of rechargeable batteries. Alternating current capacitors are specifically designed to work on line (mains) voltage AC power circuits. They are commonly used in electric motor circuits and are often designed to handle large currents, so they tend to be physically large. They are usually ruggedly packaged, often in metal cases that can be easily grounded/earthed. They also are designed with direct current breakdown voltages of at least five times the maximum AC voltage. |
If a capacitor is driven with a time-varying voltage that changes rapidly enough, at some frequency the polarization of the dielectric cannot follow the voltage. As an example of the origin of this mechanism, the internal microscopic dipoles contributing to the dielectric constant cannot move instantly, and so as frequency of an applied alternating voltage increases, the dipole response is limited and the dielectric constant diminishes. A changing dielectric constant with frequency is referred to as dielectric dispersion, and is governed by dielectric relaxation processes, such as Debye relaxation. Under transient conditions, the displacement field can be expressed as (see electric susceptibility): |
where a single prime denotes the real part and a double prime the imaginary part, Z(ω) is the complex impedance with the dielectric present, Ccmplx(ω) is the so-called complex capacitance with the dielectric present, and C0 is the capacitance without the dielectric. (Measurement "without the dielectric" in principle means measurement in free space, an unattainable goal inasmuch as even the quantum vacuum is predicted to exhibit nonideal behavior, such as dichroism. For practical purposes, when measurement errors are taken into account, often a measurement in terrestrial vacuum, or simply a calculation of C0, is sufficiently accurate.) |
The arrangement of plates and dielectric has many variations depending on the desired ratings of the capacitor. For small values of capacitance (microfarads and less), ceramic disks use metallic coatings, with wire leads bonded to the coating. Larger values can be made by multiple stacks of plates and disks. Larger value capacitors usually use a metal foil or metal film layer deposited on the surface of a dielectric film to make the plates, and a dielectric film of impregnated paper or plastic – these are rolled up to save space. To reduce the series resistance and inductance for long plates, the plates and dielectric are staggered so that connection is made at the common edge of the rolled-up plates, not at the ends of the foil or metalized film strips that comprise the plates. |
Capacitors may have their connecting leads arranged in many configurations, for example axially or radially. "Axial" means that the leads are on a common axis, typically the axis of the capacitor's cylindrical body – the leads extend from opposite ends. Radial leads might more accurately be referred to as tandem; they are rarely actually aligned along radii of the body's circle, so the term is inexact, although universal. The leads (until bent) are usually in planes parallel to that of the flat body of the capacitor, and extend in the same direction; they are often parallel as manufactured. |
Small, cheap discoidal ceramic capacitors have existed since the 1930s, and remain in widespread use. Since the 1980s, surface mount packages for capacitors have been widely used. These packages are extremely small and lack connecting leads, allowing them to be soldered directly onto the surface of printed circuit boards. Surface mount components avoid undesirable high-frequency effects due to the leads and simplify automated assembly, although manual handling is made difficult due to their small size. |
Mechanically controlled variable capacitors allow the plate spacing to be adjusted, for example by rotating or sliding a set of movable plates into alignment with a set of stationary plates. Low cost variable capacitors squeeze together alternating layers of aluminum and plastic with a screw. Electrical control of capacitance is achievable with varactors (or varicaps), which are reverse-biased semiconductor diodes whose depletion region width varies with applied voltage. They are used in phase-locked loops, amongst other applications. |
Most capacitors have numbers printed on their bodies to indicate their electrical characteristics. Larger capacitors like electrolytics usually display the actual capacitance together with the unit (for example, 220 μF). Smaller capacitors like ceramics, however, use a shorthand consisting of three numeric digits and a letter, where the digits indicate the capacitance in pF (calculated as XY × 10Z for digits XYZ) and the letter indicates the tolerance (J, K or M for ±5%, ±10% and ±20% respectively). |
Capacitors are connected in parallel with the power circuits of most electronic devices and larger systems (such as factories) to shunt away and conceal current fluctuations from the primary power source to provide a "clean" power supply for signal or control circuits. Audio equipment, for example, uses several capacitors in this way, to shunt away power line hum before it gets into the signal circuitry. The capacitors act as a local reserve for the DC power source, and bypass AC currents from the power supply. This is used in car audio applications, when a stiffening capacitor compensates for the inductance and resistance of the leads to the lead-acid car battery. |
In electric power distribution, capacitors are used for power factor correction. Such capacitors often come as three capacitors connected as a three phase load. Usually, the values of these capacitors are given not in farads but rather as a reactive power in volt-amperes reactive (var). The purpose is to counteract inductive loading from devices like electric motors and transmission lines to make the load appear to be mostly resistive. Individual motor or lamp loads may have capacitors for power factor correction, or larger sets of capacitors (usually with automatic switching devices) may be installed at a load center within a building or in a large utility substation. |
When an inductive circuit is opened, the current through the inductance collapses quickly, creating a large voltage across the open circuit of the switch or relay. If the inductance is large enough, the energy will generate a spark, causing the contact points to oxidize, deteriorate, or sometimes weld together, or destroying a solid-state switch. A snubber capacitor across the newly opened circuit creates a path for this impulse to bypass the contact points, thereby preserving their life; these were commonly found in contact breaker ignition systems, for instance. Similarly, in smaller scale circuits, the spark may not be enough to damage the switch but will still radiate undesirable radio frequency interference (RFI), which a filter capacitor absorbs. Snubber capacitors are usually employed with a low-value resistor in series, to dissipate energy and minimize RFI. Such resistor-capacitor combinations are available in a single package. |
In single phase squirrel cage motors, the primary winding within the motor housing is not capable of starting a rotational motion on the rotor, but is capable of sustaining one. To start the motor, a secondary "start" winding has a series non-polarized starting capacitor to introduce a lead in the sinusoidal current. When the secondary (start) winding is placed at an angle with respect to the primary (run) winding, a rotating electric field is created. The force of the rotational field is not constant, but is sufficient to start the rotor spinning. When the rotor comes close to operating speed, a centrifugal switch (or current-sensitive relay in series with the main winding) disconnects the capacitor. The start capacitor is typically mounted to the side of the motor housing. These are called capacitor-start motors, that have relatively high starting torque. Typically they can have up-to four times as much starting torque than a split-phase motor and are used on applications such as compressors, pressure washers and any small device requiring high starting torques. |
Capacitors may retain a charge long after power is removed from a circuit; this charge can cause dangerous or even potentially fatal shocks or damage connected equipment. For example, even a seemingly innocuous device such as a disposable-camera flash unit, powered by a 1.5 volt AA battery, has a capacitor which may contain over 15 joules of energy and be charged to over 300 volts. This is easily capable of delivering a shock. Service procedures for electronic devices usually include instructions to discharge large or high-voltage capacitors, for instance using a Brinkley stick. Capacitors may also have built-in discharge resistors to dissipate stored energy to a safe level within a few seconds after power is removed. High-voltage capacitors are stored with the terminals shorted, as protection from potentially dangerous voltages due to dielectric absorption or from transient voltages the capacitor may pick up from static charges or passing weather events. |
Capacitors may catastrophically fail when subjected to voltages or currents beyond their rating, or as they reach their normal end of life. Dielectric or metal interconnection failures may create arcing that vaporizes the dielectric fluid, resulting in case bulging, rupture, or even an explosion. Capacitors used in RF or sustained high-current applications can overheat, especially in the center of the capacitor rolls. Capacitors used within high-energy capacitor banks can violently explode when a short in one capacitor causes sudden dumping of energy stored in the rest of the bank into the failing unit. High voltage vacuum capacitors can generate soft X-rays even during normal operation. Proper containment, fusing, and preventive maintenance can help to minimize these hazards. |
The history of science is the study of the development of science and scientific knowledge, including both the natural sciences and social sciences. (The history of the arts and humanities is termed as the history of scholarship.) Science is a body of empirical, theoretical, and practical knowledge about the natural world, produced by scientists who emphasize the observation, explanation, and prediction of real world phenomena. Historiography of science, in contrast, often draws on the historical methods of both intellectual history and social history. |
The English word scientist is relatively recent—first coined by William Whewell in the 19th century. Previously, people investigating nature called themselves natural philosophers. While empirical investigations of the natural world have been described since classical antiquity (for example, by Thales, Aristotle, and others), and scientific methods have been employed since the Middle Ages (for example, by Ibn al-Haytham, and Roger Bacon), the dawn of modern science is often traced back to the early modern period and in particular to the scientific revolution that took place in 16th- and 17th-century Europe. Scientific methods are considered to be so fundamental to modern science that some consider earlier inquiries into nature to be pre-scientific. Traditionally, historians of science have defined science sufficiently broadly to include those inquiries. |
From the 18th century through late 20th century, the history of science, especially of the physical and biological sciences, was often presented in a progressive narrative in which true theories replaced false beliefs. More recent historical interpretations, such as those of Thomas Kuhn, tend to portray the history of science in different terms, such as that of competing paradigms or conceptual systems in a wider matrix that includes intellectual, cultural, economic and political themes outside of science. |
The development of writing enabled knowledge to be stored and communicated across generations with much greater fidelity. Combined with the development of agriculture, which allowed for a surplus of food, it became possible for early civilizations to develop, because more time and effort could be devoted to tasks (other than food production) than hunter-gatherers or early subsistence farmers had available. This surplus allowed a community to support individuals who did things other than work towards bare survival. These other tasks included systematic studies of nature, study of written information gathered and recorded by others, and often of adding to that body of information. |
Ancient Egypt made significant advances in astronomy, mathematics and medicine. Their development of geometry was a necessary outgrowth of surveying to preserve the layout and ownership of farmland, which was flooded annually by the Nile river. The 3-4-5 right triangle and other rules of thumb were used to build rectilinear structures, and the post and lintel architecture of Egypt. Egypt was also a center of alchemy research for much of the Mediterranean.The Edwin Smith papyrus is one of the first medical documents still extant, and perhaps the earliest document that attempts to describe and analyse the brain: it might be seen as the very beginnings of modern neuroscience. However, while Egyptian medicine had some effective practices, it was not without its ineffective and sometimes harmful practices. Medical historians believe that ancient Egyptian pharmacology, for example, was largely ineffective. Nevertheless, it applies the following components to the treatment of disease: examination, diagnosis, treatment, and prognosis, which display strong parallels to the basic empirical method of science and according to G. E. R. Lloyd played a significant role in the development of this methodology. The Ebers papyrus (c. 1550 BC) also contains evidence of traditional empiricism. |
From their beginnings in Sumer (now Iraq) around 3500 BC, the Mesopotamian people began to attempt to record some observations of the world with numerical data. But their observations and measurements were seemingly taken for purposes other than for elucidating scientific laws. A concrete instance of Pythagoras' law was recorded, as early as the 18th century BC: the Mesopotamian cuneiform tablet Plimpton 322 records a number of Pythagorean triplets (3,4,5) (5,12,13). ..., dated 1900 BC, possibly millennia before Pythagoras, but an abstract formulation of the Pythagorean theorem was not. |
In Babylonian astronomy, records of the motions of the stars, planets, and the moon are left on thousands of clay tablets created by scribes. Even today, astronomical periods identified by Mesopotamian proto-scientists are still widely used in Western calendars such as the solar year and the lunar month. Using these data they developed arithmetical methods to compute the changing length of daylight in the course of the year and to predict the appearances and disappearances of the Moon and planets and eclipses of the Sun and Moon. Only a few astronomers' names are known, such as that of Kidinnu, a Chaldean astronomer and mathematician. Kiddinu's value for the solar year is in use for today's calendars. Babylonian astronomy was "the first and highly successful attempt at giving a refined mathematical description of astronomical phenomena." According to the historian A. Aaboe, "all subsequent varieties of scientific astronomy, in the Hellenistic world, in India, in Islam, and in the West—if not indeed all subsequent endeavour in the exact sciences—depend upon Babylonian astronomy in decisive and fundamental ways." |
In Classical Antiquity, the inquiry into the workings of the universe took place both in investigations aimed at such practical goals as establishing a reliable calendar or determining how to cure a variety of illnesses and in those abstract investigations known as natural philosophy. The ancient people who are considered the first scientists may have thought of themselves as natural philosophers, as practitioners of a skilled profession (for example, physicians), or as followers of a religious tradition (for example, temple healers). |
The earliest Greek philosophers, known as the pre-Socratics, provided competing answers to the question found in the myths of their neighbors: "How did the ordered cosmos in which we live come to be?" The pre-Socratic philosopher Thales (640-546 BC), dubbed the "father of science", was the first to postulate non-supernatural explanations for natural phenomena, for example, that land floats on water and that earthquakes are caused by the agitation of the water upon which the land floats, rather than the god Poseidon. Thales' student Pythagoras of Samos founded the Pythagorean school, which investigated mathematics for its own sake, and was the first to postulate that the Earth is spherical in shape. Leucippus (5th century BC) introduced atomism, the theory that all matter is made of indivisible, imperishable units called atoms. This was greatly expanded by his pupil Democritus. |
Subsequently, Plato and Aristotle produced the first systematic discussions of natural philosophy, which did much to shape later investigations of nature. Their development of deductive reasoning was of particular importance and usefulness to later scientific inquiry. Plato founded the Platonic Academy in 387 BC, whose motto was "Let none unversed in geometry enter here", and turned out many notable philosophers. Plato's student Aristotle introduced empiricism and the notion that universal truths can be arrived at via observation and induction, thereby laying the foundations of the scientific method. Aristotle also produced many biological writings that were empirical in nature, focusing on biological causation and the diversity of life. He made countless observations of nature, especially the habits and attributes of plants and animals in the world around him, classified more than 540 animal species, and dissected at least 50. Aristotle's writings profoundly influenced subsequent Islamic and European scholarship, though they were eventually superseded in the Scientific Revolution. |
The important legacy of this period included substantial advances in factual knowledge, especially in anatomy, zoology, botany, mineralogy, geography, mathematics and astronomy; an awareness of the importance of certain scientific problems, especially those related to the problem of change and its causes; and a recognition of the methodological importance of applying mathematics to natural phenomena and of undertaking empirical research. In the Hellenistic age scholars frequently employed the principles developed in earlier Greek thought: the application of mathematics and deliberate empirical research, in their scientific investigations. Thus, clear unbroken lines of influence lead from ancient Greek and Hellenistic philosophers, to medieval Muslim philosophers and scientists, to the European Renaissance and Enlightenment, to the secular sciences of the modern day. Neither reason nor inquiry began with the Ancient Greeks, but the Socratic method did, along with the idea of Forms, great advances in geometry, logic, and the natural sciences. According to Benjamin Farrington, former Professor of Classics at Swansea University: |
The astronomer Aristarchus of Samos was the first known person to propose a heliocentric model of the solar system, while the geographer Eratosthenes accurately calculated the circumference of the Earth. Hipparchus (c. 190 – c. 120 BC) produced the first systematic star catalog. The level of achievement in Hellenistic astronomy and engineering is impressively shown by the Antikythera mechanism (150-100 BC), an analog computer for calculating the position of planets. Technological artifacts of similar complexity did not reappear until the 14th century, when mechanical astronomical clocks appeared in Europe. |
In Hellenistic Egypt, the mathematician Euclid laid down the foundations of mathematical rigor and introduced the concepts of definition, axiom, theorem and proof still in use today in his Elements, considered the most influential textbook ever written. Archimedes, considered one of the greatest mathematicians of all time, is credited with using the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, and gave a remarkably accurate approximation of Pi. He is also known in physics for laying the foundations of hydrostatics, statics, and the explanation of the principle of the lever. |
Theophrastus wrote some of the earliest descriptions of plants and animals, establishing the first taxonomy and looking at minerals in terms of their properties such as hardness. Pliny the Elder produced what is one of the largest encyclopedias of the natural world in 77 AD, and must be regarded as the rightful successor to Theophrastus. For example, he accurately describes the octahedral shape of the diamond, and proceeds to mention that diamond dust is used by engravers to cut and polish other gems owing to its great hardness. His recognition of the importance of crystal shape is a precursor to modern crystallography, while mention of numerous other minerals presages mineralogy. He also recognises that other minerals have characteristic crystal shapes, but in one example, confuses the crystal habit with the work of lapidaries. He was also the first to recognise that amber was a fossilized resin from pine trees because he had seen samples with trapped insects within them. |
Mathematics: The earliest traces of mathematical knowledge in the Indian subcontinent appear with the Indus Valley Civilization (c. 4th millennium BC ~ c. 3rd millennium BC). The people of this civilization made bricks whose dimensions were in the proportion 4:2:1, considered favorable for the stability of a brick structure. They also tried to standardize measurement of length to a high degree of accuracy. They designed a ruler—the Mohenjo-daro ruler—whose unit of length (approximately 1.32 inches or 3.4 centimetres) was divided into ten equal parts. Bricks manufactured in ancient Mohenjo-daro often had dimensions that were integral multiples of this unit of length. |
Indian astronomer and mathematician Aryabhata (476-550), in his Aryabhatiya (499) introduced a number of trigonometric functions (including sine, versine, cosine and inverse sine), trigonometric tables, and techniques and algorithms of algebra. In 628 AD, Brahmagupta suggested that gravity was a force of attraction. He also lucidly explained the use of zero as both a placeholder and a decimal digit, along with the Hindu-Arabic numeral system now used universally throughout the world. Arabic translations of the two astronomers' texts were soon available in the Islamic world, introducing what would become Arabic numerals to the Islamic World by the 9th century. During the 14th–16th centuries, the Kerala school of astronomy and mathematics made significant advances in astronomy and especially mathematics, including fields such as trigonometry and analysis. In particular, Madhava of Sangamagrama is considered the "founder of mathematical analysis". |
Astronomy: The first textual mention of astronomical concepts comes from the Vedas, religious literature of India. According to Sarma (2008): "One finds in the Rigveda intelligent speculations about the genesis of the universe from nonexistence, the configuration of the universe, the spherical self-supporting earth, and the year of 360 days divided into 12 equal parts of 30 days each with a periodical intercalary month.". The first 12 chapters of the Siddhanta Shiromani, written by Bhāskara in the 12th century, cover topics such as: mean longitudes of the planets; true longitudes of the planets; the three problems of diurnal rotation; syzygies; lunar eclipses; solar eclipses; latitudes of the planets; risings and settings; the moon's crescent; conjunctions of the planets with each other; conjunctions of the planets with the fixed stars; and the patas of the sun and moon. The 13 chapters of the second part cover the nature of the sphere, as well as significant astronomical and trigonometric calculations based on it. |
Medicine: Findings from Neolithic graveyards in what is now Pakistan show evidence of proto-dentistry among an early farming culture. Ayurveda is a system of traditional medicine that originated in ancient India before 2500 BC, and is now practiced as a form of alternative medicine in other parts of the world. Its most famous text is the Suśrutasamhitā of Suśruta, which is notable for describing procedures on various forms of surgery, including rhinoplasty, the repair of torn ear lobes, perineal lithotomy, cataract surgery, and several other excisions and other surgical procedures. |
Mathematics: From the earliest the Chinese used a positional decimal system on counting boards in order to calculate. To express 10, a single rod is placed in the second box from the right. The spoken language uses a similar system to English: e.g. four thousand two hundred seven. No symbol was used for zero. By the 1st century BC, negative numbers and decimal fractions were in use and The Nine Chapters on the Mathematical Art included methods for extracting higher order roots by Horner's method and solving linear equations and by Pythagoras' theorem. Cubic equations were solved in the Tang dynasty and solutions of equations of order higher than 3 appeared in print in 1245 AD by Ch'in Chiu-shao. Pascal's triangle for binomial coefficients was described around 1100 by Jia Xian. |
Astronomy: Astronomical observations from China constitute the longest continuous sequence from any civilisation and include records of sunspots (112 records from 364 BC), supernovas (1054), lunar and solar eclipses. By the 12th century, they could reasonably accurately make predictions of eclipses, but the knowledge of this was lost during the Ming dynasty, so that the Jesuit Matteo Ricci gained much favour in 1601 by his predictions. By 635 Chinese astronomers had observed that the tails of comets always point away from the sun. |
Seismology: To better prepare for calamities, Zhang Heng invented a seismometer in 132 CE which provided instant alert to authorities in the capital Luoyang that an earthquake had occurred in a location indicated by a specific cardinal or ordinal direction. Although no tremors could be felt in the capital when Zhang told the court that an earthquake had just occurred in the northwest, a message came soon afterwards that an earthquake had indeed struck 400 km (248 mi) to 500 km (310 mi) northwest of Luoyang (in what is now modern Gansu). Zhang called his device the 'instrument for measuring the seasonal winds and the movements of the Earth' (Houfeng didong yi 候风地动仪), so-named because he and others thought that earthquakes were most likely caused by the enormous compression of trapped air. See Zhang's seismometer for further details. |
There are many notable contributors to the field of Chinese science throughout the ages. One of the best examples would be Shen Kuo (1031–1095), a polymath scientist and statesman who was the first to describe the magnetic-needle compass used for navigation, discovered the concept of true north, improved the design of the astronomical gnomon, armillary sphere, sight tube, and clepsydra, and described the use of drydocks to repair boats. After observing the natural process of the inundation of silt and the find of marine fossils in the Taihang Mountains (hundreds of miles from the Pacific Ocean), Shen Kuo devised a theory of land formation, or geomorphology. He also adopted a theory of gradual climate change in regions over time, after observing petrified bamboo found underground at Yan'an, Shaanxi province. If not for Shen Kuo's writing, the architectural works of Yu Hao would be little known, along with the inventor of movable type printing, Bi Sheng (990-1051). Shen's contemporary Su Song (1020–1101) was also a brilliant polymath, an astronomer who created a celestial atlas of star maps, wrote a pharmaceutical treatise with related subjects of botany, zoology, mineralogy, and metallurgy, and had erected a large astronomical clocktower in Kaifeng city in 1088. To operate the crowning armillary sphere, his clocktower featured an escapement mechanism and the world's oldest known use of an endless power-transmitting chain drive. |
The Jesuit China missions of the 16th and 17th centuries "learned to appreciate the scientific achievements of this ancient culture and made them known in Europe. Through their correspondence European scientists first learned about the Chinese science and culture." Western academic thought on the history of Chinese technology and science was galvanized by the work of Joseph Needham and the Needham Research Institute. Among the technological accomplishments of China were, according to the British scholar Needham, early seismological detectors (Zhang Heng in the 2nd century), the water-powered celestial globe (Zhang Heng), matches, the independent invention of the decimal system, dry docks, sliding calipers, the double-action piston pump, cast iron, the blast furnace, the iron plough, the multi-tube seed drill, the wheelbarrow, the suspension bridge, the winnowing machine, the rotary fan, the parachute, natural gas as fuel, the raised-relief map, the propeller, the crossbow, and a solid fuel rocket, the multistage rocket, the horse collar, along with contributions in logic, astronomy, medicine, and other fields. |
With the division of the Roman Empire, the Western Roman Empire lost contact with much of its past. In the Middle East, Greek philosophy was able to find some support under the newly created Arab Empire. With the spread of Islam in the 7th and 8th centuries, a period of Muslim scholarship, known as the Islamic Golden Age, lasted until the 13th century. This scholarship was aided by several factors. The use of a single language, Arabic, allowed communication without need of a translator. Access to Greek texts from the Byzantine Empire, along with Indian sources of learning, provided Muslim scholars a knowledge base to build upon. |
Muslim scientists placed far greater emphasis on experiment than had the Greeks. This led to an early scientific method being developed in the Muslim world, where significant progress in methodology was made, beginning with the experiments of Ibn al-Haytham (Alhazen) on optics from c. 1000, in his Book of Optics. The law of refraction of light was known to the Persians. The most important development of the scientific method was the use of experiments to distinguish between competing scientific theories set within a generally empirical orientation, which began among Muslim scientists. Ibn al-Haytham is also regarded as the father of optics, especially for his empirical proof of the intromission theory of light. Some have also described Ibn al-Haytham as the "first scientist" for his development of the modern scientific method. |
In mathematics, the Persian mathematician Muhammad ibn Musa al-Khwarizmi gave his name to the concept of the algorithm, while the term algebra is derived from al-jabr, the beginning of the title of one of his publications. What is now known as Arabic numerals originally came from India, but Muslim mathematicians did make several refinements to the number system, such as the introduction of decimal point notation. Sabian mathematician Al-Battani (850-929) contributed to astronomy and mathematics, while Persian scholar Al-Razi contributed to chemistry and medicine. |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.