Enzian
The Enzian was a German WWII surface-to-air anti-aircraft missile, the first to use a radio controlled guidance system. During the missile's development in the late stages of the war it was plagued by organisational problems and was cancelled before becoming operational; as early as 1943 it was becoming clear Messerschmitt's Me 163 interceptor would be difficult to use in combat. After flying to the 25,000–30,000 ft altitude of allied bombers, it had only a few minutes to find them and make an attack before running out of fuel. If the aircraft did accomplish this, it had the additional problem of lacking a weapon that could be aimed while closing on the target at some 400 mph. Dr. Herman Wurster of Messerschmitt proposed an answer in the form of Flak Rakete 1 in 1943. Instead of tracking down the planes, the rocket would fly just in front of the target and detonate a 500 kg warhead, in the hope of bringing down several bombers at once. With no human pilot on board, thus no need to limit takeoff acceleration, the rocket could use solid fuel boosters, reducing the amount of fuel needed for the rest of the climb by the sustainer motor, a Walther RI-10B.
The liquid fueled sustainer used a combination of SV-Stoff and Br-Stoff, catalyzed by an amount of T-Stoff. The result with the heavy warhead, was that a much smaller airframe was needed to carry the required fuel - so small it could be portable and launched from a modified 88 mm gun mounting; the design made as much use of wood as possible, due to the need to conserve other "strategic" materials in the deteriorating war situation. For the same reasons a new type of Walter rocket was envisioned, a modification of the engine in the Me 163 that would burn coal-gas instead of the hydrogen peroxide used in other Walter designs. Thrust was reduced in flight, from 2,000 kg to 1,000 kg; the missile, which resembled the Me 163 would be guided under radio control from the ground. The operator would fly the missile into the vicinity of the bombers cut the engine and let it glide; this presented a real problem in the Enzian. Other German missiles were high-speed designs that could be flown directly at their target along the line of sight, straightforward for an operator on the ground.
The Enzian would instead be approaching its target from somewhere in front, harder for the operator. Many experiments with radio and wire-guided missiles had demonstrated real problems with last-minute terminal guidance corrections; the initial plans for solving this problem were rather advanced. The large airframe left plenty of room in the nose, which the designers intended to fill with a self-contained radar unit called Elsass. In the short term it was planned to use some sort of proximity fuze while flying the missile through the bomber stream; the warhead, of which several were studied, was to have a nominal lethal radius of 45 m. Several elaborations of the basic design were carried out, resulting in the FR-1 through FR-5; the FR-5 was considered to be a reasonable starting point, so development commenced on the newly named Enzian E.1 in September 1943. By May 1944, 60 airframes were complete, awaiting their engines. In order to gain flight test data they were fitted with RATO units instead.
A series of 38 flight tests commenced with favourable results, but the engine still lagged. Dr. Konrad, the designer of the engine of the Rheintochter missile, was asked to modify his design for use in the Enzian. On consideration, it appeared this was a much better solution anyway, after January 1945 there were no plans to use the Walter design; the resulting E-4 version with the Konrad engine was considered the production version. Because of difficulties in perfecting the proximity fuze, an infrared homing system, was proposed, allowing Enzian to be flown right to the target; however the system was never developed beyond a test-bench mockup. On 17 January 1945, all development projects were cancelled by the Luftwaffe in order to concentrate all possible efforts on only two designs, the Messerschmitt Me 262 and the Heinkel He 162. Although this was the official story, many in the Nazi and Luftwaffe hierarchy had their own pet projects continue. Enzian was judged further from completion than Henschel's Schmetterling missile, so it was cancelled.
Messerschmitt engineers continued some low-level work on the project, hoping it would be re-funded, but by March it was clear the cancellation order would not be rescinded and all development efforts ceased. Only two Enzian missiles are known to have survived the war. One is on display at the Royal Air Force Museum Cosford and the other is in storage at the Australian War Memorial's Treloar Resource Centre after being displayed for many years at the Royal Australian Air Force Museum. "Enzian" is the name of the foil character in Thomas Pynchon's Gravity's Rainbow, contrasted against the main character Slothrop's association with the V-2. List of World War II guided missiles of Germany AIM-9 Sidewinder List of missiles Enzian E-4
Arthur Rudolph
Arthur Louis Hugo Rudolph was a German rocket engineer, a leader of the effort to develop the V-2 rocket for Nazi Germany. After World War II, the United States Government's Office of Strategic Services brought him to the U. S. as part of the clandestine Operation Paperclip, where he became one of the main developers of the U. S. space program. He worked within the U. S. Army and NASA, where he managed the development of several systems, including the Pershing missile and the Saturn V Moon rocket. In 1984, the U. S. Government investigated him for war crimes, he agreed to renounce his United States citizenship and leave the U. S. in return for not being prosecuted. Rudolph was born in Stepfershausen, Germany in 1906, his family were farmers, with a long tradition in the area. His father Gustav, died in 1915 while serving in World War I. Arthur and his younger brother Walter were raised by Ida; when Ida noticed young Arthur had a mechanical gift, she decided he should attend technical training. Walter inherited the family farm.
From 1921 on, Rudolph attended the technical school in Schmalkalden for three years. In 1924 he found employment at a silver goods factory in Bremen. In August 1927 Rudolph accepted a job at Co. in Berlin. After a few months, he became a toolmaker at Fritz Werner. In 1928 he attended the Technical College of Berlin— now the Technical University of Berlin —graduating in 1930 with the equivalent of a Bachelor of Science degree in mechanical engineering. On May 1, 1930, Rudolph began working for the Heylandt Works in Berlin where he met rocketry pioneer Max Valier.:54 Valier had use of the factory grounds for his experiments in rocketry and Rudolph became interested, working with Valier in his spare time along with Walter Riedel. Rudolph had some interest in rocketry, having read Wege zur Raumschiffahrt by Hermann Oberth and having seen the 1929 film Woman in the Moon. On May 17, an experimental engine killed Valier. Dr. Paulus Heylandt forbade further rocket research, but Rudolph continued secretly with Riedel and Alfons Pietsch.
Rudolph developed an improved and safer version of Valier's engine while Pietsch designed a rocket car. Dr. Heylandt conceded to back the project, the "Heylandt Rocket Car" was born and was exhibited at Tempelhof Aerodrome. While it was a technical success, the fuel costs were greater than the admissions received and performances were discontinued. Rudolph joined the Nazi Party in 1931 later the SA.:38Rudolph first met Wernher von Braun when he visited a meeting of the Verein für Raumschiffahrt. In May 1932 Rudolph was looking for work when he encountered Pietsch. After forming a partnership Rudolph began design on a new engine. Pietsch met with Walter Dornberger, tasked by the German Ordnance Department to develop a rocket weapons system and had become interested in the VfR. After demonstrating the new engine to Dornberger, Rudolph moved to the proving grounds at Kummersdorf along with Riedel, began working under von Braun. Rudolph's engine was used in the Aggregat series of rockets. In December 1934, the von Braun team launched two A-2 rockets from the island of Borkum.
Static testing on the A-3 engines began in Kummersdorf in late 1936 and were observed by General Werner von Fritsch, the commander-in chief of the German Army High Command. The Kummersdorf facilities were inadequate for continued operations, so the von Braun team was moved to Peenemünde in May 1937 where Rudolph was tasked with the building of the A-3 test stand; the Rudolphs lived in nearby Zinnowitz, where their daughter, Marianne Erika, was born on November 26, 1937. The A-3 series was never proved successful. In early 1938, Dornberger put Rudolph in charge of the design for the new production plant to be built at Peenemünde for the A-4 series renamed the V-2. In August 1943, as Rudolph was ready to begin production of the V-2, the British bombed Peenemünde. After Peenemünde was bombed, the V-2 production facility was moved to the Mittelwerk facility, near Nordhausen and underground. Mittelwerk was a gypsum mine, being used as a storage facility and was being excavated for production facilities.
The labor force consisted of prisoners who were housed at the Mittelbau-Dora concentration camp. Rudolph was in charge of moving the equipment from Peenemünde to Mittelwerk, working under Albin Sawatzki. After the plant was in place, Rudolph was operations director for V-2 missile production.:16 Sawatzki decreed that fifty were to be produced in December. Given the labor and parts issues, Rudolph was able to produce four rockets that were returned from Peenemünde as defective. There are estimates that between 12–20,000 prisoners died while building the V-2 rockets at Mittelwerk. More than the actual V-2 bombardments. In 1944, Himmler convinced Hitler to put the V-2 project directly under SS control, in August replaced Dornberger with SS General Hans Kammler as its director. In January 1945 the SS ordered all of the civilians and prisoners, including Rudolph and his team, to attend a public hanging of six to twelve prisoners accused of sabotage. By March 1945, production had stopped due to a lack of parts and Rudolph and his staff were moved to Oberammergau where they met von Braun and others from Peenemünde.
They surrendered to the U. S. Army and were transported to Garmisch. Rudolph was transferred to the British to participate in Operation Backfire from July to October 1945.:99 He was transferred back to the Americans. The U. S. Army picked up Martha and Marianne Rudolph from Stepfershaus
Rechlin–Lärz Airfield
Rechlin–Lärz Airfield is an airfield in the village of Rechlin, Mecklenburg-Western Pomerania, Germany. The airport is not used for scheduled traffic but features general aviation and is home to other leisure activities as well. Additionally, the music festival Fusion Festival takes place here; the airport was once part of the Third Reich era's Luftwaffe main testing ground, or Erprobungsstelle for new aircraft designs, the heart of, centered on two large turf areas some 4.5 km due north of the 21st century era paved-runway airport facility. The core airfield of the Luftwaffe facility took the form of a typical pre-World War II aerodrome, with no defined "runways", being bounded by a hexagonal-layout perimeter road that still exists today, defining an area 1,700 meters across within it of about 234.3 hectares, or 578.9 acres, which today is the site of the annual Fusion music festival. The Rechlin data sheets on Luftwaffe and captured Allied aircraft are considered by many aviation historians to be among the most reliable sources for aircraft performance data from the World War II era.
Its role was taken over after 1945 by the Bundeswehr military aviation installation at Manching, within West German borders, since Rechlin was well inside the borders of East Germany for 45 years. Construction of the first airfield at Rechlin started in 1916. After the end of World War I, the airfield was closed again and many of its installations dismantled. During the 1920s, the airfield was reopened as a civilian airbase, but it was soon used as a testing ground for the secret German air force experiments under the Treaty of Rapallo; the site was chosen for its remote location in an uninhabited area. On February 26, 1936, per order of Wehrmacht Generalfeldmarschall Werner von Blomberg, the Rechlin airfield became the official testing ground of the newly formed Luftwaffe; the turf-surfaced site, still bounded by the aforementioned hexagonal-layout ring road around its perimeter, was designated as the central Erprobungsstelle test facility of the Luftwaffe, was expanded by constructing two more airfields: a second, smaller turf-surfaced field just east of the main site in nearby Roggentin and just south of the main site at Lärz, the latter of which became the modern 21st century airfield site.
Construction work on the airfields and the accompanying barracks was carried out by forced labor from nearby concentration camp Ravensbrück. Many of the Luftwaffe's new combat aircraft prototypes were test flown at the main turf-fielded Rechlin facilities. After several Allied bombing runs on the primary turf-surfaced aerodrome field of Rechlin, the satellite Roggentin airfield in 1944, testing of late-war planes was shifted just southwards to Lärz. On April 10, 1945, a final bomber attack by the US Army Air Forces – amounting to 11 B-17s and 159 B-24s from the 8th Air Force, targeting airfields used by German jet fighters – completely destroyed the airfields. In 1946, the Soviet Air Force established a permanent presence at the airbase; the 19th Guards fighter-bomber regiment of the 16th Air Army and a helicopter squadron were stationed at Lärz. Military usage of the airfields continued until 1993, when the last Russian air force units were moved home; the Rechlin airfield was reopened for civilian use in 1994.
German language Wikipedia page for the Erprobungsstelle Rechlin test facility Erprobungsstelle Tarnewitz, one of the coastal Erprobungsstellen on the Baltic Sea under control from the Rechlin HQ facility Luftfahrtforschungsanstalt, the largest aviation research facility of the Third Reich near Völkenrode, but without an airfield of its own. Transport in Germany List of airports in Germany Edgar Petersen, the World War II Luftwaffe colonel who commanded both the Rechlin facility, was the "KdE", or commander for the entire Luftwaffe test department late in the war. Hanna Reitsch Oslo Report, which divulged the Erprobungstelle facility early in the war to the British Media related to Rechlin-Lärz Airfield at Wikimedia Commons Official website Website of the aviation museum in Rechlin Website of the cultural organization Kulturkosmos located at Rechlin–Lärz Airfield Accident history for REB at Aviation Safety Network Current weather for EDAX at NOAA/NWS RonaldV's "Abandoned, Forgotten & Little-Known Airfields in Europe" listing
RWTH Aachen University
RWTH Aachen University or Rheinisch-Westfälische Technische Hochschule Aachen is a research university located in Aachen, North Rhine-Westphalia, Germany. With more than 42,000 students enrolled in 144 study programs, it is the largest technical university in Germany; the university maintains close links to industry and accounts for the highest amount of third-party funds of all German universities in both absolute and relative terms per faculty member. In 2007, RWTH Aachen was chosen by the DFG as one of nine German Universities of Excellence for its future concept RWTH 2020: Meeting Global Challenges and additionally won funding for one graduate school and three clusters of excellence. RWTH Aachen is a founding member of IDEA League, a strategic alliance of four leading universities of technology in Europe; the university is a member of TU9, DFG and the Top Industrial Managers for Europe network. On 25 January 1858, prince Frederick William of Prussia, was given a donation of 5,000 talers from the Aachener und Münchener Feuer-Versicherungs-Gesellschaft, the precursor of the AachenMünchener insurance company, for charity.
In March, the prince chose to use the donation to found the first Prussian institute of technology somewhere in the Rhine province. The seat of the institution remained undecided over years. Aachen won with a financing concept backed by the insurance company and by local banks. Groundbreaking for the new Polytechnikum took place on 15 May 1865 and lectures started during the Franco-Prussian War on 10 October 1870 with 223 students and 32 teachers; the new institution had as its primary purpose the education of engineers for the mining industry in the Ruhr area. The unclear position of the new Prussian polytechnika affected the first years. Polytechnics lacked prestige in society and the number of students decreased; this began to change in 1880 when the early RWTH, amongst others, was reorganized as a Royal Technical University, gained a seat in the Prussian House of Lords and won the right to bestow Dr.-Ing. Degrees and Dipl.-Ing. Titles. In the same year, over 800 male students enrolled. In 1909 the first women were admitted and the artist August von Brandis succeeded Alexander Frenz at the Faculty of Architecture as a "professor of figure and landscape painting", Brandis became dean in 1929.
World War I, proved a serious setback for the university. Many students voluntarily joined up and died in the war, parts of the university were shortly occupied or confiscated. While the TH Aachen flourished in the 1920s with the introduction of more independent faculties, of several new institutes and of the general students' committee, the first signs of nationalist radicalization became visible within the university; the Third Reich's Gleichschaltung of the TH in 1933 met with low resistance from both students and faculty. Beginning in September 1933, Jewish and Communist professors were systematically persecuted and excluded from the university. Vacant Chairs were given to NSDAP party-members or sympathizers; the freedom of research and teaching became limited, institutes important for the regime's plans were systematically established, existing chairs promoted. Closed in 1939, the TH continued courses in 1940, although with a low number of students. On 21 October 1944, when Aachen capitulated, more than 70% of all buildings of the university were destroyed or damaged.
After World War II ended in 1945 the university expanded quickly. In the 1950s, many professors, removed because of their alleged affiliation with the Nazi party were allowed to return and a multitude of new institutes were founded. By the late 1960s, the TH had 10,000 students, making it the foremost of all German technical universities. With the foundation of philosophical and medical faculties in 1965 and 1966 the university became more "universal"; the newly founded faculties in particular began attracting new students, the number of students doubled twice from 1970 to 1980 and from 1980 to 1990. Now, the average number of students is around 42,000, with about one third of all students being women. By relative terms, the most popular study-programs are engineering, natural science and humanities and medicine. In December 2006, RWTH Aachen and the Sultanate of Oman signed an agreement to establish a private German University of Technology in Muscat. Professors from Aachen aided in developing the curricula for the five study-programs and scientific staff took over some of the first courses.
In 2007, RWTH Aachen was chosen as one of nine German Universities of Excellence for its future concept RWTH 2020: Meeting Global Challenges, earning it the connotation of being an elite university. However, although the list of universities honored for their future concepts consists of large and respected institutions, the Federal Ministry of Education and Research claimed that the initiative aimed at promoting universities with a dedicated future concept so they could continue researching on an int
Desiccant
A desiccant is a hygroscopic substance that induces or sustains a state of dryness in its vicinity. Encountered pre-packaged desiccants are solids that absorb water. Desiccants for specialized purposes may be in forms other than solid, may work through other principles, such as chemical bonding of water molecules, they are encountered in foods to retain crispness. Industrially, desiccants are used to control the level of water in gas streams. Although some desiccants are chemically inert, others are reactive and require specialized handling techniques; the most common desiccant is silica, an otherwise inert, water-insoluble white solid. Tens of thousands of tons are produced annually for this purpose. Other common desiccants include activated charcoal, calcium sulfate, calcium chloride, molecular sieves. One measure of desiccant efficiency is the ratio of water storable in the desiccant relative to the mass of desiccant. Another measure is the residual relative humidity of the air or other fluid being dried.
The performance of any desiccant varies with temperature and both relative humidity and absolute humidity. To some extent, desiccant performance can be described, but most the final choice of which desiccant best suits a given situation, how much of it to use, in what form, is made based on testing and practical experience. Sometimes a humidity indicator is included in the desiccant to show, by color changes, the degree of water-saturation of the desiccant. One used indicator is cobalt chloride. Anhydrous cobalt chloride is blue; when it bonds with two water molecules, it turns purple. Further hydration results in the pink hexaaquacobalt chloride complex Cl2. One example of desiccant usage is in the manufacture of insulated windows where zeolite spheroids fill a rectangular spacer tube at the perimeter of the panes of glass; the desiccant helps to prevent the condensation of moisture between the panes. Another use of zeolites is in the dryer component of air conditioning systems to help maintain the efficacy of the refrigerant.
Desiccants are commonly used to protect goods in shipping containers against moisture damage. Hygroscopic cargo, such as cocoa and various nuts and grains, are susceptible to mold and rot when exposed to condensation and humidity; because of this, shippers take precautionary measures to protect against cargo loss. Desiccants reduce the amount of moisture present in air. Desiccants come in various forms and have found widespread use in the food, packing and many manufacturing industries. Air conditioning systems can be made based on desiccants. Desiccants are used in different kinds of livestock farming to dry newborn animals, such as piglets; the use of a good desiccant can help them dry quicker and save energy, which can be crucial for the animal's development. Another use is to reduce bacteria and pathogens that thrive in wet surfaces, reducing bacteria pressure. However, some desiccants have a high pH-level, which can be harmful for an animal's skin. Desiccants are used to remove water from solvents required by chemical reactions that do not tolerate water, e.g. the Grignard reaction.
The method though not always, involves mixing the solvent with the solid desiccant. Studies show that molecular sieves are superior as desiccants relative to chemical drying reagents such as sodium-benzophenone. Sieves offer the advantages of being recyclable. Desiccator Humidity buffering Humidity indicator card Hygroscopy Moisture sorption isotherm Solar air conditioning Oxygen scavenger Sorbent Volatile Corrosion Inhibitor Lavan, Z.. "Second Law Analysis of Desiccant Cooling Systems". Journal of Solar Energy Engineering. 104: 229–236. Doi:10.1115/1.3266307. S. Sadik. "True potato seed drying over rice". Potato Research. 25: 269. Doi:10.1007/BF02357312
Operation Hydra (1943)
Operation Hydra was an attack RAF Bomber Command on a German scientific research centre at Peenemünde on the night of 17/18 August 1943. Group Captain John Searby, CO of 83 Squadron, commanded the operation, the first time that Bomber Command used a master bomber to direct the attack of the main force. Hydra began a campaign against the German V-weapon programme; the British lost 215 aircrew, 40 bombers and killed several hundred enslaved workers in the nearby Trassenheide labour camp. The Luftwaffe lost twelve night-fighters and about 170 German civilians were killed, including two V-2 rocket scientists. Prototype V-2 rocket launches were delayed for about two months and production was dispersed and the morale of the German survivors was affected. To evade the restrictions of the Treaty of Versailles the Reichswehr studied the possibility of using rockets to compensate for the limited amount of heavy artillery allowed by the treaty; the head of the ballistics and Munitions Section, Colonel Becker suggested that short-range anti-aircraft rockets be designed and accurate, longer-range missiles should be produced to carry gas or high explosives.
In 1931, Captain Walter Dornberger joined the Ordnance Department to research rocket development. Dornberger led a group of researchers through the infancy of the new technology and secured funds at the expense of other fields of research. Other scientists studied the use of rockets for maritime rescue, weather data collection, postal services across the Alps and the Atlantic and a journey to the moon. Information had reached the British Secret Intelligence Service about German weapons development since the Oslo report of November 1939, from Royal Air Force photo-reconnaissance photographs taken from 22 April 1943 and eavesdropping on Lieutenant-General Wilhelm Ritter von Thoma, who expressed surprise that there had been no rocket bombardment of Britain. Other prisoners of war gave various and sometimes fanciful accounts. Information came from Polish intelligence, a Danish chemical engineer and from Leon Henri Roth and Dr Schwagen Luxembourgish enrolés de force who had worked at Peenemünde and smuggled out letters describing rocket research, giving conflicting accounts of the size, warhead range and means of propulsion of the device.
Despite the confusion, there was little doubt that the Germans were working on a rocket and in April 1943, the Chiefs of Staff warned operational HQs of the possibility of rocket weapons. Duncan Sandys was appointed by Winston Churchill to lead an inquiry to study the information and report on counter-measures. At a meeting, Sandys introduced the aerial photographs of Peenemünde and Professor Frederick Lindemann, scientific advisor to Churchill, judged the information to be a hoax but R. V. Jones refuted Lindemann; the committee recommended stopping reconnaissance flights to Peenemünde, to avoid alerting the Germans, Peenemünde is … beyond the range of our radio navigation beams and … we must bomb by moonlight, although the German night fighters will be close at hand and it is too far to send our own. We must attack it on the heaviest possible scale. At 10 Downing St on 15 July, the Chiefs of Staff, Herbert Morrison and Churchill examined the bombing plan and ordered an attack as soon as the moon and weather permitted.
For accuracy, the raid was to take place during a full moon and the bombers would have to fly at 8,000 ft instead of the normal altitude of 19,000 ft. Peenemünde was around 600 mi from the closest British airbase, was spread over a wide area and was protected by smoke screens. All of Bomber Command was to fly on the raid and practice raids on areas similar to Peenemünde were made; the primary objective was to kill as many personnel involved in the research and development of the V-weapons as possible, by bombing the workers' quarters. Secondary objectives were to render the research facility useless and "destroy as much of the V-weapons, related work, documentation as possible"; the aircraft from 5 Group had practised a distance method for bombing. H2S radar worked best over contrasting areas of ground and open water and 5 Group was to fly an approach run from Cape Arkona on the island of Rügen, to Thiessow to check time and heading. From Thiessow to the islet of Rüden any adjustments were to be made, followed by a timed run to Peenemünde on Usedom.
The nature of the raid was not revealed to the aircrews. To scare aircrews into making a maximum effort, Order 176 emphasised the importance of the raid: "If the attack fails...it will be repeated the next night and on ensuing nights regardless, within practicable limits, of casualties. To divert German night fighters from Operation Hydra, eight Pathfinder Force Mosquitoes of 139 Squadron flew to Whitebait to simulate the opening of a Main Force raid. By imitating the typical pathfinder marking of the target, it was expected that German night fighters would by lured to Berlin. At 22:56 British Double Summer Time, the first Mosquito was over Whitebait; each Mosquito was to drop a minimum bomb load. Fighter Command provided 28 Mosquito and ten Beaufighter intruders from 25, 141, 410, 418 and 605 squadrons in two waves, to attack Luftwaffe airfields at Ardorf, Jagel and Grove, to catch night fighte
World War II
World War II known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries; the major participants threw their entire economic and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China, it included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, the only use of nuclear weapons in war. Japan, which aimed to dominate Asia and the Pacific, was at war with China by 1937, though neither side had declared war on the other. World War II is said to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and the United Kingdom.
From late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Finland and the Baltic states. Following the onset of campaigns in North Africa and East Africa, the fall of France in mid 1940, the war continued between the European Axis powers and the British Empire. War in the Balkans, the aerial Battle of Britain, the Blitz, the long Battle of the Atlantic followed. On 22 June 1941, the European Axis powers launched an invasion of the Soviet Union, opening the largest land theatre of war in history; this Eastern Front trapped most crucially the German Wehrmacht, into a war of attrition. In December 1941, Japan launched a surprise attack on the United States as well as European colonies in the Pacific. Following an immediate U. S. declaration of war against Japan, supported by one from Great Britain, the European Axis powers declared war on the U.
S. in solidarity with their Japanese ally. Rapid Japanese conquests over much of the Western Pacific ensued, perceived by many in Asia as liberation from Western dominance and resulting in the support of several armies from defeated territories; the Axis advance in the Pacific halted in 1942. Key setbacks in 1943, which included a series of German defeats on the Eastern Front, the Allied invasions of Sicily and Italy, Allied victories in the Pacific, cost the Axis its initiative and forced it into strategic retreat on all fronts. In 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained its territorial losses and turned toward Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in Central China, South China and Burma, while the Allies crippled the Japanese Navy and captured key Western Pacific islands; the war in Europe concluded with an invasion of Germany by the Western Allies and the Soviet Union, culminating in the capture of Berlin by Soviet troops, the suicide of Adolf Hitler and the German unconditional surrender on 8 May 1945.
Following the Potsdam Declaration by the Allies on 26 July 1945 and the refusal of Japan to surrender under its terms, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August respectively. With an invasion of the Japanese archipelago imminent, the possibility of additional atomic bombings, the Soviet entry into the war against Japan and its invasion of Manchuria, Japan announced its intention to surrender on 15 August 1945, cementing total victory in Asia for the Allies. Tribunals were set up by fiat by the Allies and war crimes trials were conducted in the wake of the war both against the Germans and the Japanese. World War II changed the political social structure of the globe; the United Nations was established to foster international co-operation and prevent future conflicts. The Soviet Union and United States emerged as rival superpowers, setting the stage for the nearly half-century long Cold War. In the wake of European devastation, the influence of its great powers waned, triggering the decolonisation of Africa and Asia.
Most countries whose industries had been damaged moved towards economic expansion. Political integration in Europe, emerged as an effort to end pre-war enmities and create a common identity; the start of the war in Europe is held to be 1 September 1939, beginning with the German invasion of Poland. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred and the two wars merged in 1941; this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935; the British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the fo
