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Italy enters the war alongside Germany and against Great Britain and France

Dunkirk. The British lost two encryption machines on the beaches of Dunkirk. The Germans found them. They compared them with their own three-disk Enigma, which they deemed impossible to decrypt. Since the British machine had five disks, they considered it even more impossible, so they

Tens of thousands of British and French soldiers massed at Dunkirk under German fire

Rommel breaks through into Belgium and France, and is decorated with the Knight’s Cross of the Iron Cross

Auschwitz, Poland. Pressed by the spread of partisan warfare in the Governatorate, the occupied territories of Poland, the Nazis decided to create a concentration camp that could house a large number of deportees and a complex infrastructure of businesses and industries to employ the labor.

The German army invades Denmark, where Niel Bohr is staying. He has already donated his gold Nobel medal to charity, but he is keeping the two Nobel medals of his German Jewish colleagues Max von Laue (X-ray diffraction) and James Franck (energy quantization). Any gold

Mauthausen, Austria. The Gusen subcamp (NebenLager) is built, 4 km from Mauthausen (4,000 prisoners at the end of the year). It is the first of 56 subcamps, distributed throughout the industrial area adjacent to Vienna and the central Upper Austria region. Prisoners are employed in

Germany invades Denmark and Norway

Ruth Ive, Sir Winston Churchill’s future telephone censor in his talks with Roosevelt, is hired at the Censorship Headquarters in London.

Atomic fission, USA: The first $6,000 for the graphite experiment arrives. From this moment on, secrecy begins; the scientific results are no longer published to the scientific community.

Italian East Africa (AOI). The Italian population in AOI is 166,000, of which 80,000 are in Ethiopia, excluding military personnel (who account for approximately another 300,000 soldiers).

memorandum, written in England by Otto Frisch and Rudolf Peierls, contains all the fundamental elements of nuclear warfare technology: it speaks of a super-bomb that would use the energy of the atomic nucleus, producing an explosion of 1,000 tons of dynamite, with temperatures comparable to

United States. The first working betatron is built: unlike cyclotrons, it uses magnetic induction to accelerate electrons. Shortly thereafter, it accelerates electrons to 99.99% the speed of light. Then, in 1944, Herb Pollock leads a team at General Electric Research Labs in Schenectady, New York,

In Mozambique, there are 27,400 foreigners, and in Angola, 44,000 whites. In Guinea, there are only 1,400, including the military.

Deportation of hundreds of thousands of Poles, Ukrainians, Balts, Moldovans, Bessarabs, Volga Germans, Crimean Tatars, Chechens, Ingush

The German Schnorkel is the first diesel-powered submarine (with tubular air intakes)

The Institute for Advanced Study in Princeton is moving to a new location.

Englishmen Ernest Chain and Walter Florey develop stable penicillin. They help save 82 million lives (estimate updated at the beginning of the 21st century).

Aircraft use “Inline Pistons” engines (example: Mustang)

Russell Shoemaker Ohl at Bell Labs Holmdel accidentally discovers some peculiar features of the pn junction and shows the results to Brattain

United States. Industrial aircraft production, for wartime reasons, increases in less than two years, from ninety planes a month to 5,000 a month. The largest factory in the world is three times larger than the German one and five times larger than the Japanese one.

Alfred Lee Loomis conceives the idea of a precision long-range radio navigation system: the Loran

H.W. Bode publishes “Relations between Attenuation and Phase in Feedback Amplifier Design” in the Bell System Technical Journal, a fundamental contribution to the theory of feedback systems.

CBS shows the first color television; it uses rotating color discs

Claude Elwood Shannon applies Boolean algebra to electrical relays

In the USA the construction of the Mark I begins and in Germany that of the Z4, both valve machines capable of one multiplication per second.

Finland. The Soviets are beginning to digest the bitter lesson of their failure to cut Finland in two: they are suffering enormous losses. They therefore halt their advance north and concentrate a huge number of troops and tanks in the open terrain of the Karelian

The US Army consists of 170,000 men

Kurt Godel and his wife left Vienna for Princeton, USA, reaching it by Trans-Siberian Railway, passing through Japan from where they sailed to San Francisco, arriving at their destination only in March 1940; Godel would never set foot on European soil again.

The British were able to break Nazi codes written on Enigma machines with the new rotors introduced in December 1938.

Bell Labs laboratories in New York: William Bradford Shockley, in his lab note book writes: “it has today occurred to me that an amplifier using semiconductors rather than vacuum is in principle possible”.

During the Russo-Finnish War, the Finns provided the British with a significant amount of encrypted material, which led Bletchley Park to crack the Red Army code (the GKK) and the naval code (the OKF). The Finns also captured and handed over five codebooks, captured from

Winter War. The Soviet Union launches a massive military attack against Finland. The excuse (and it truly was) is some cannon fire the Soviets claim to have received, killing several soldiers. Years later, Khrushchev would admit that those cannon shots were fired by the Red

The Littorio Assault Division was formed, composed of the 33rd Tank Regiment, the 12th Bersaglieri Regiment, and the 133rd Littorio Artillery Regiment; it fought in the Alps, the Balkans, and North Africa; at El Alamein, it was almost completely wiped out by the British. The

British intelligence agency MI6 receives an unsigned letter (the “Oslo Letter” or “Oslo Report”) revealing mysterious details about German secret weapons in one of the most spectacular leaks in the history of military intelligence. The report, compiled by German physicist Hans Ferdinand Mayer, describes several

Bletchley Park. The first “Bombe” is ordered, the machine designed by Alan Turing to automatically decrypt Enigma.

New York. Work has been completed on Rockefeller Center, commissioned by oil magnate John D. Rockefeller Jr.

United States. Alexander Sachs of Lehman Corporation delivers a letter signed by Albert Einstein to Roosevelt. The letter, written by Szilard, Wigner, and Teller and signed by Einstein, contains a request to launch a research program into the nuclear use of atomic fission.

The Soviet Union makes territorial demands to Lithuania, Latvia, Estonia, and Finland. The first three accept and are annexed. Finland refuses and is invaded militarily. Despite having a population 50 times smaller than the Soviet Union and a vastly superior Red Army, the Finns offer

Bletchley Park. Approximately 1,120,000 messages out of 1,550,000 sent by the Kriegsmarine Enigma were decrypted (Hut 8 statistics). Only 530,000 were sent to the Admiralty, the rest being considered of little importance. These interceptions would make a difference to the course of the war.

Claude Shannon publishes “A mathematical theory of communication”, where he introduces concepts such as the information content of a message, the information deficit, its entropy, and the Shannon Limit.

Bletchley Par+H7117k. Only two people believe it’s possible to crack the Enigma code. These are Frank Birch and, of course, Alan Turing.

At the beginning of the war, German soldiers consumed about 2,570 calories a day. By the end of the war, this figure had dropped to 1,412 calories.

Paris. Polish General Sikorski forms a national unity cabinet, immediately recognized by Great Britain, where he will soon move. Sikorski has at his disposal the entire navy, the underground Krajowa army, active in Poland and 400,000 men strong, and finally, later, the Second Polish Army

After suffering from jaw cancer for sixteen years, Sigmund Freud dies after a fatal injection of morphine, administered by his doctor at Freud’s explicit request.

Date of the letter from Jesuit Ettore Caselli, referring to the death of Ettore Majorana: he writes that the magazine Missioni has agreed to establish a scholarship for the late and dearly departed Ettore Majorana. He speaks of it as if it were a homily

London. Winston Churchill receives his first letter from Franklin Delano Roosevelt. After a chilly relationship with Chamberlain, he established a close correspondence with Churchill (over 2,000 letters), which well represents what (especially from the British side) is considered the Special Relationship.

England. The day after Neville Chamberlain declared war on Germany following the invasion of Poland, Alan Turing was invited by the Government Code & Cypher School to become a fellow cryptanalyst at Bletchley, and moved from the opulence of Cambridge to the Crown Inn at

Adolf Hitler sets out from Berlin for the Polish border to witness the first sequence of the tragedy that will destroy him and his time, and will bring the old world to its knees before the new. The Führer’s personal train, a curious omen, is

Beginning of World War II: Germany invades Poland

The number of war deaths during World War II rose to a staggering 300 per 100,000 people per year, or 0.3% per year. These are the rates Jared Diamond also recorded in dozens of hunter-gatherer tribes around the world. Analyzing the 20th century as a

In the USSR, there were 82 functioning camps of the GULag system (Glavnoe Upravlenie LAGerej: Central Directorate of Camps), with 2,350,000 prisoners.

Robert J. Oppenheimer and Jean Tatlock’s stormy relationship disintegrated. At a party in Pasadena, he met a married woman: Kitty Harrison. Oppie was famous for his parties, and for his martinis on the rocks (chilled glasses with a rim dipped in lime and honey), for

Dane Niels Bohr and American John Wheeler publish in Physical Review: “The Mechanism of Nuclear Fission”

American J. Robert Oppenheimer and his student Hartland Snyder publish in Physical Review: “On Continued Gravitational Collapse” which describes the physics of a black hole.

Ernest Orlando Lawrence of the University of California at Berkeley wins the Nobel Prize for his invention of the cyclotron.

Leo Szilard correctly predicts that uranium can sustain a fission chain reaction

Regular television broadcasts begin in the USA

American Julian Kahn invents the spray can

The “Wind Bag” patent was issued as a flatulence remedy designed to “receive and store gas formed by the digestion of foods.” A tube connected the rectum to a collection chamber held attached to the body by a belt.

Poland. French and British cryptoanalysts arrive at the headquarters of Biuro Szyfrow, who had been tasked years earlier with trying to decrypt Enigma. He had hired the country’s best mathematicians, including Marian Rejewski, who started by identifying some weaknesses: repetition is the enemy of security,

Signal Intelligence: The Germans develop the Schlüsselgerät 39 (SG-39) machine to replace Enigma, but it never goes into production. It is a nearly impenetrable machine, featuring rewireable reflectors (similar to the 1944 UKD), four rotors with variable notches, three mechanical wheels, and a configurable input

Washington, DC, United States. After receiving an introductory letter from physics professor George Pergram, Admiral Stanford Hooper of the US Navy meets with Enrico Fermi, who informs him of the possibility of using a new explosive (uranium) with a power a million times greater than

United States. To facilitate Enrico Fermi’s work, physics professor George Pergram wrote Admiral Stanford Hooper a letter introducing the potential of uranium for warfare. The following day, Enrico Fermi met with the US Navy, advised by Leo Szilard, to discuss the possibility of using a

Stalin offers Hitler support against England in exchange for a free hand in Finland, the Dardanelles, and Persia. Hitler refuses.

The Spanish Civil War is won by the Francoists

The development of radar technology takes priority in America over nuclear technology for warfare purposes; in fact, the use of radar is correctly considered more useful in the short term; as a consequence, the best minds in the country, particularly at MIT, work on radar,

Hans Bethe publishes the article “Energy Production in Stars,” explaining the CNO (Carbon-Nitrogen-Oxygen) reaction that occurs in stellar nuclei. It will be understood only later that this occurs in stars heavier than the Sun, while for stars like our own Sun, the nuclear fusion reaction

While at the barbershop in San Francisco, Luis Alvarez reads in the newspaper about Hahn and Strassman’s nuclear fission experiment in Germany. He immediately leaves the barbershop and runs to Oppenheimer to tell him the news. Robert reacts skeptically, saying “impossible.” But the next day,

United States. Enrico Fermi speculates on the size of the crater produced by the fission of one kilogram of uranium. He estimates that one pound of fissile material produces an explosion equivalent to 15,000 tons of TNT. A small number of scientists now realize the

United States. Niels Bohr announces the discovery of uranium fission. Physicists are astonished, and many rush to their laboratories, still in their evening suits, to repeat Otto Hahn’s experiment. Within a few days, an unspecified number of uranium atoms are split in various locations across

Leo Szilard has already realized the potential use of nuclear fission to create a bomb, Lewis Strauss reports.

Niels Bohr believes it is impossible to isolate and purify uranium-235, which is necessary for the chain reaction, since it is in a proportion of 1:150 with uranium-238 which is inert in this type of process.

Niels Bohr arrives in America and visits Princeton where he communicates the discovery of atomic fission in Germany

Philosopher Jean Paul Sartre publishes Outline for a Theory of Emotions

In Stagecoach, John Wayne wears jeans for the first time (and not the frayed leather trousers of the early Westerns).

John Hovie designs the Jeep

Iguacu National Park, the second in Brazil, is inaugurated in Brazil

J. Robert Oppenheimer and Hartland Snyder study the case of the collapse of a star into a black hole in the case of fully symmetric gravitational collapse, using Schwarzschild geometry.

Horace Babcock, measuring the rotation rate of the Andromeda Galaxy, obtained the unexpected result that the rotation of the outer parts of the disk was much faster than expected from Newton’s laws of universal gravitation. These results, in the 1970s and 1980s, were generalized to