Atomic Pioneers
PART 1  |  DAWN OF THE ATOM
526 B.C. - 1941 A.D.

DAWN OF THE ATOM | Introduction:

The story of the atom begins with the history of atomic physics, which has its origins at the dawn of western civilization.  The word “Atom” is derived from the Greek term "Atomos" – meaning indivisible.  Great philosophers such as Plato and Aristotle mused long on the ingredients of our physical world. Plato wrote of Leucippus and his pupil, Democritus, who are credited with the theory of “Atoms and Void” which described the existence of matter in space. These concepts would later be fostered by scientists of the seventeenth century. With an in-depth look at the early chemists and physicists searching for the atom, ATOM DAYS explores the breakthroughs by nineteenth century scientists such as Michael Faraday and James Maxwell who opened the door to the atomic century. After Maxwell and early pioneers such as James Rutherford, Albert Einstein’s theory of relativity published in 1905, solved key problems in the atomic inquiry. This culminated in the science of nuclear physics and paved the way for breakthroughs by atomic pioneers including James Chadwick, Leo Szilard and Enrico Fermi. ATOM DAYS explores the work of these scientists and shows how these early discoveries and advances in physics were soon diverted for darker military purposes. With the threat of Adolph Hitler’s fascist state looming, many eminent European atomic scientists fled from persecution and came to the United States including Albert Einstein. In 1939, Einstein wrote to President Roosevelt warning that the German scientific community might have the knowledge to make an atomic bomb. On December 7th, 1941, the Japanese navy attacked the U.S. naval base at Pearl Harbor. Soon after, the United States Government heeded the warnings from Einstein and other prominent scientists about the possibility of developing atomic weapons.

526 BC | Pythagoras

Pythagoras was one of western civilization’s first great mathematicians. He traveled throughout the known world during his life and studied math, science, music as well as eastern and western religions and philosophies. While he opposed the concept of matter as invisible particles that comprised the world, he stimulated consideration in the topic by scientists that followed him. He is eternally credited with the fundamental geometric law of the Pythagorean Theorem; that bears his name and states “the square of the hypotenuse of a right triangle is equal to the sum of its sides." This theory provided western civilization the basic foundation for future developments in architecture, geometry and advanced mathematics.
(Atomic Pioneers by Ray and Roselyn Hiebert, pp. 8-7)

450 BC | Leucippus & Democritus

Leucippus and his pupil, Democritus, are credited with the theory of “Atoms and Void” which implied the existence of matter in space. They theorized that the universe was separated into a vast vacuum of space and the substance of material things were comprised of tiny invisible particles. The word "Atom" is derived from the Greek word "Atomos"; meaning indivisible. Their theories also implied that the substance of the physical world is eternally changing and yet the atoms themselves are changeless and forever eternal.
(Atomic Pioneers by Ray and Roselyn Hiebert, pp. 14-15)

200 BC | Archimedes

Archimedes is considered one of the most important scientists of ancient times. He was the son of the astronomer Pheildias and a relative of King Hieron who presided over the Greek province of Syracuse. He is credited with the invention of  several military weapons including huge lenses that were used set enemy ships on fire and mechanical cranes that could capsize them. One of his most important contributions to science was his idea of relative densities, which proved that substances could be weighed and measured accurately. This idea became the basis for the concept of atomic weights.
(Atomic Pioneers by Ray and Roselyn Hiebert, pp. 14-15)

1513 | Nicolas Copernicus

Nicolas Copernicus, whose real name was Nicolas Koppernigk, was the first great scientist of the Renaissance. He came from a noble polish family. His Uncle was a prince and helped him acquire a fine education. Nicolas Copernicus described a solar system, which stated that the Sun was the center of the Universe and heavenly bodies revolve around it in circular orbits. This controversial theory challenged religious and scientific status quo of the times that stated that the Earth was the center of the Universe. Mathematical evidence later proved his theory correct. His discoveries in astronomy led scientists that followed him to use a mathematical approach to the explanation of the heavens and our physical universe.
(Atomic Pioneers by Ray and Roselyn Hiebert, pp. 18-19)

1630 | Galileo Galilee

Galileo Galilee used improved telescopes and mathematical equations to support Copernicus’s heliocentric theory. His practical work in mathematics laid the foundations for Isaac Newton’s First Law of Motion. He constructed the first operational telescope and was the first person to closely observe the surface of the moon. He discovered the satellites of Jupiter, the rings Saturn and spots on the Sun. His mathematical and astronomical observations proved Copernicus’s heliocentric theory and laid the foundations for the theories of motion. He revived the atomists’ theories that suggested atoms had different sizes, weights and velocities.
(Atomic Pioneers by Ray and Roselyn Hiebert, pp. 23-24)

1650 | Robert Boyle

Robert Boyle is considered by many as the father of modern chemistry. He provided evidence of the theory that substances could be broken down into their most elemental parts though chemical analysis. This laid the foundation for the development of the periodic table and the discovery of the individual naturally occurring elements.
(Atomic Pioneers by Ray and Roselyn Hiebert, pp. 23-24)

1676 | Ole Roemer

Ole Roemer proved the existence of the speed of light based on the exact timing of the appearance of Jupiter’s moon Io during different phases of the earths orbit around the sun. Galileo had predicted this in earlier times. Roemer measured the speed of light to be approximately 670,000.000 mph; which is close to the best current estimate.
 (E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 41-45)

1695 | Isaac Newton

Isaac Newton is perhaps the most influential scientist who ever lived. His work in mathematics, optics, and physics laid the foundations for much of modern science. Newton invented integral calculus and helped develop theoretical astronomy. He defined the Laws of Motion and Gravity, which he used to precisely predict the motion of the planets around the sun. He created a unified system of physical laws that could be applied to nearly every natural phenomena. His contributions to mathematics and his laws of motion enabled later scientists to develop the laws of physics.
 (Atomic Pioneers, by Ray and Roselyn Hiebert pp. 33-35)

1747 | Emilie Du Chatelet

Emilie Du Chatelet built on Newton’s Laws of Motion and proved the definition of energy (mv2) previously theorized by Gottfried Leibniz. This theory claimed that an objects energy is equal to its mass multiplied by the square of it’s velocity. She found evidence of this in the experiments of Willems ‘sGravesande. ‘sGravesande precisely dropped brass balls into soft clay at various measured heights. He showed that if a ball was dropped two times as fast it embedded four times as far into the clay and if it was dropped three times as fast it embedded nine times as far.
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 64-65)

1790 | Antoine Laurent Lavoisier

Antoine Laurent Lavoisier was an an ill-fated accountant and scientist under King Louis XVI, who demonstrated that all forms of matter are linked together. His experiments proved that air molecules attached to rusted metal whereby the mass of the metal increased by the exact amount that the mass of the air decreases. This became known as the "Conservation of Mass" and suggested there was a finite amount of mass in the universe. Lavoisier suggested by crude chemistry experiments that mass changes forms over time but regardless of its form, the same amount of mass always exists. Wood turns to smoke but no mass is ever lost or gained it is simply transmuted into a different form. Lavoisier was also responsible for the construction of the infamous Paris Wall that incorporated tolls at all entrances to increase taxation revenues for King Louis XVI. The wall was hated by Parisians and became a symbol of tyranny. When the French revolution began it was attacked and torn down two days before the famous storming of the Bastille. Shortly after the overthrow of King Louis XVI, Lavoisier was arrested along with other members of various aristocratic and political establishments and was eventually executed by Guillotine.
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis pp. 29-34)

1821 | Michael Faraday

Michael Faraday was a bookbinder with a limited formal education. At age twenty he attended a lecture on electricity by Sir Humphrey Davy of the Royal Institute and became interested in science. His lack of education became an asset as it forced him to approached science from a purely experimental perspective. Eventually he became Davy’s student and discovered magnetic “Lines of Force” suggesting electric current emits invisible particles in the form of electromagnetism. He accomplished this by connecting a single dangling brass wire to another wire with electric current and put them in the vicinity of a strong magnet. The dangling wire instantly began to twirl in a circular motion suggesting invisible radiating energy was interacting with it. With this experiment Faraday actually created the first rudimentary electric motor and more importantly proved that different forms of energy are linked together. This lead to the theory of The Conservation of Energy, which identified that not only are all various forms of energy linked but there is also a finite amount of energy in the Universe and none is ever gained or lost. One form of energy is merely transformed into another.
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 15-18)

1870 | James Clerk Maxwell

James Clerk Maxwell was arguably the finest mathematical mind of the nineteenth century. He corresponded and met with Michael Faraday late in Faraday’s life to discuss his “invisible lines of force” and Faraday’s theory of electro-magnetism. Most physicists of the time still did not embrace Faraday’s theories. Maxwell recognized the genius crude drawings and diagrams of Faraday’s experiments and created mathematical models that supported them and validated the existence of invisible forces of electromagnetic waves. He extended these theories to include the leapfrogging effect that occurs in electromagnetic waves as they travel at the speed of light. His work was later applied to the Einstein’s theory of relativity.
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 46-49)
(The Making of the Atomic Bomb by Richard Rhodes, pp. 30)

1887 | Heinrich Hertz

Heinrich Hertz discovered Electric Waves, which eventually led to the technology we now know as radio. Hertz accomplished this by experimenting with a spark generator, which became known as a Hertzian oscillator. He discovered that when two metal plates were charged with electrical current to create a spark. Two other uncharged plates placed in vicinity of the charge plates would also spark. This proved that some invisible part of the electric current traveled through space to the other plates. This discovery led other scientists to begin looking into the possibility of invisible atomic structures of matter and energy.
(The Making of the Atomic Bomb by Richard Rhodes, pp. 36-37)

1897 | JJ Thompson

JJ Thompson followed early work on cathode ray tubes and demonstrated that the glow in the tubes was not composed of light waves, as previously thought, but rather cathode rays were part of cathode matter that could be deflected by an electric field. Since these particles were lighter than any known matter, he surmised that they must be some element or building block of the atom. This confirmed the existence of the “electron” and proved the sub atomic structure of matter. Thompson went on to be one of the key pioneers of the atomic inquiry. (The Making of the Atomic Bomb by Richard Rhodes, pp. 38)

1898 | Marie Curie

Marie Curie was the French-Polish chemist who is credited along with her husband Pierre and Henri Becquerel with the discovery of radioactivity. They were awarded the Nobel Prize in Physics for their discovery in 1903. Marie studied uranium and other radioactive materials and conducted experiments proving these materials were releasing energy in the form of atomic particles. This led chemist and physicists to believe certain substances had different atomic properties. Maria Curie died of leukemia as the result of her long-term exposure to radiation.
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 75)

1900 | Max Plank

Max Plank, introduced quantum theory into the mechanics of classic physics in 1900. His theory explained why vibrating particles of light could only radiate certain types of energies. This "permission" of energies was determined by a quantum value. The word "Quantum"  is derived from the Latin word "Quantus", meaning how great. This suggested that energy could be measured by color (or frequency) rather than simply by intensity. This law was eventually used to measure all types of energy signatures by color.
(The Making of the Atomic Bomb by Richard Rhodes, pp. 67-68)

1905 | Albert Einstein

Albert Einstein published his Theory of Relativity in 1905; which included the world’s most famous equation "E=mc2". The equation is actually the link between the realms of energy and matter described as a mathematical formula. In basic terms, the formula describes the following as it relates to atomic physics:

E is for energy, the result of the equation.

m is for matter, the value for mass of any element measured by this variable.

c is for "Celeritas", which means “Swiftness” in Latin. It is the value for the speed of light; which is approximately 670 million miles per hour.

Therefore, c2 (the speed of light squared) is approximately 448,900,000,000,000,000 in units of miles per hour. According to the equation, the mass variable is then multiplied by this number. At these values, one can begin to imagine the raw power of the equation and the scale of energy potentially locked away inside mass at the atomic level.

Author David Bodanis has eloquently described the process in simple terms:

“Visualize the equals sign in the equation as a tunnel or a bridge. A very little amount of mass gets enormously magnified whenever it travels through the equation and emerges on the side of energy."

E=mc2 is somewhat difficult to grasp because it is impossible for us to perceive our physical world at the speed of light. As an analogy, one can think about the speed of sound, which travels at a much slower speed (approximately 761 mph) and therefore is conceptually easier to imagine. To humans sound is louder if we walk closer to the source and softer if we walk away from the source. An insect, however, might spend a lifetime to travel the distance to the source and therefore never perceive a difference in the loudness of the sound. If we could perceive our physical world at the speed of light we would be able to see physical  signs of Einstein’s theory. If we observed an object approaching the speed of light, it would appear to increase in size because it’s mass would increase as the equation works in reverse.

Einstein’s work on his theories were purely theoretical. He made no experiments and he had no laboratory. He simply put all the clues discovered so far in the emerging field of physics together and conceptually bridged the realms of matter and energy. In doing so, he redefined the limits of the physical universe. Once the scientific community realized the implications of the theory, the race was on to unlock the secrets of the atom.
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 69)
(http://www.grc.nasa.gov)

1911 | Ernest Rutherford

Ernest Rutherford, JJ Thomson’s protégé, published his atomic theory in 1911 that described the atom as mostly empty space which included a central nucleus with a positive electronic charge surrounded by negatively charged electronic particles called electrons. Rutherford theorized the structure of the atom using an experiment that involved firing radioactive particles through minutely thin gold foil using screens coated with zinc sulfide to detect the particles on the other side of the foil. He found that only about 1 in 8000 of the particles were deflected by the nuclei of the gold foil atoms. This led him to the theory that the atom was almost entirely composed of empty space.
(The Making of the Atomic Bomb by Richard Rhodes, pp. 48-77)

1914 | Otto Hahn

When World War 1 began, many chemist and physicists working on the mysteries of the atom were diverted to more practical sciences for the war effort. In Germany, a brilliant young scientist named Otto Hahn turns from radiochemistry to creating the first weapons of mass destruction – Poison Gas. Hahn became a lieutenant in the German military, installed gas containers and directed gas attacks on the Western Front. Germany, due to its number of chemists and large chemical industry was far ahead of its adversaries in science and chemical warfare. After World War I, Hahn went back to work in nuclear physics and later worked on the German atom bomb project in World War Two.
(The Making of the Atomic Bomb by Richard Rhodes, pp. 91-93)

1922 | Niels Bohr

in 1922, Niels Bohr, the Danish theoretical physics student who studied at Cambridge under JJ Thomson, and then at Manchester under Rutherford identified the sub atomic radiochemistry of matter. He learned that radioactive properties of matter originated from the nucleus and chemical properties of matter depended on the frequency and arrangement of electrons around the nucleus. Therefore, an elements position on the periodic table should correspond to its atomic number of electrons rather than, as chemists thought, by atomic weight. This meant that hydrogen, having one electron, is the first element on the periodic table. Helium is second with 2 electrons, and uranium last with 92 electrons. Armed with this information Bohr proposed what he called “stationary states” inside the atom that allowed for obits for electrons that would not become unstable. This provided a theoretical framework for Rutherford’s model of the atom with a central nucleus and explained how the atom could remain stable under Newton’s Laws. Bohr’s work earns him the Nobel Prize and laid the course for atomic physics in the twentieth century.
(The Making of the Atomic Bomb by Richard Rhodes, pp. 67-71)

1932 | James Chadwick

In 1932, James Chadwick, a student under Earnest Rutherford, identified the neutron particles of the atom. It is named so, due to its electrically neutral state. Chadwick was able to pass radiation particles through the shell of the negatively charged electrons surrounding the atom indicating that these particles had no positive or negative properties. This confirmed Rutherford's theory that the atom was composed of almost entirely empty space. Since the neutron was as large as a proton but unaffected by both the atom’s shell of electrons and the electrical barrier of its nucleus, it instantly became apparent that this was a method that could probe the atoms nucleus and perhaps unlock the vast stores of energy proposed by Einstein’s equation E=mc2. Chadwick’s discovery of this new elementary particle opened the door to the atomic century. It was thought this development would quickly lead to many breakthroughs. However, Chadwick and other scientists found they were unsuccessful at directing streams of neutrons from radiation to interact with the nucleus of the atom.
(The Making of the Atomic Bomb by Richard Rhodes, pp. 164-165)
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 96-97)

1933 | Adolph Hitler

In 1933, Adolph Hitler rose to power under the post World War I anti-socialist political movement in Germany and was eventually elected Chancellor. He immediately began legislation of anti semitic laws. This policy led to the eventual exodus of Germany's largely Jewish community of physicists over the next few years, which was partly organized by Albert Einstein and Leo Szilard. Hitler became aware of scientific discoveries in the atomic inquiry and directed Non-Jewish German scientists to pursue work on the possibility of an atomic bomb. German Universities fired their Jewish faculty including Lise Meitner. Meitner later went on to theorize the instability of the uranium atom and suggested the possibility of a chain reaction of energy from the uranium isotope. This observation was a key contribution to the understanding of atomic fission and eventually contributed to the development of the atomic bomb by her exiled contemporaries.
(The Making of the Atomic Bomb by Richard Rhodes, pp. 164-165)

1933 | Leo Szilard

Leo Szilard was a Hungarian theoretician who had studied under Albert Einstein at the University of Berlin where he received his doctorate in Physics in 1922. He fled Germany in 1933 and helped form the Academic Assistance Council organized by Einstein that assisted Jewish scientists escape Nazi persecution. Up to that time, he had not focused on atomic physics. Unemployed and now living in the Imperial Hotel in London, Szilard read the headline “BREAKING DOWN THE ATOM” in the September 12th issue of the London Times. The article summarized Earnest Rutherford’s recent speech highlighting his doubts that the atom could ever be used as a source of energy on an industrial scale. Szilard later described his atomic epiphany…“ This sort of set me pondering as I walked the streets of London, and I remembered that I stopped for a red light at the intersection of Southampton Row…I was pondering whether Lord Rutherford might not prove to be wrong...It occurred to me that neutrons, in contrast to alpha particles, do not ionize (electrically interact with) the substance they pass through ...Consequently, neutrons need not stop until they hit a nucleus with which they may react.”

“As the light changed to green and I crossed the street…it suddenly occurred to me that if we could find an element which is split by neutrons and which would emit two neutrons when it absorbed one neutron, such an element, if assembled in sufficiently large mass, could sustain a nuclear chain reaction…liberate energy on an industrial scale and construct atom bombs.”
(http://www.dannen.com/chronbio.html)
(The Making of the Atomic Bomb by Richard Rhodes, pp. 26-28)

1934 | Enrico Fermi

In 1934, Enrico Fermi, a Professor of Theoretical Physics at the University of Rome, realized that bombarding an atom's nucleus with neutrons at high speeds resulted in them passing right through the vast empty space of the atom and missing the central nucleus. So instead he experimented with passing radiation though water to collide with large H2o molecules which slowed the neutrons. This process finally allowed for experiments on the nucleus of the atom. The results Fermi and other scientist found was only a minor flux of energy release from the nuclei. This was far from the calculations of c2 and Szilard’s chain reaction theory. It soon became obvious that something was still missing. Fermi used his technique to bombard every element on the periodic table, starting with hydrogen the lightest element, and ending with uranium the heaviest element. Fermi found that bombarding uranium 238 with slowed neutrons created a new, unearthly heavier isotope - uranium 235. Fermi became the world’s foremost expert on neutrons and began to collaborate with Leo Szilard on the possibility of creating an atomic chain reaction. He was awarded the nobel prize in physics in 1938 "... for his demonstrations of the existence of new radioactive elements produced by neutron irradiation, and for his related discovery of nuclear reactions brought about by slow neutrons." Fermi's wife Laura was jewish and by1938, fascist Italy began to follow Nazi Germany with an anti-semitism campaign against Jews. Fermi moved his family to the United States to accept an appointment as Professor of Physics at Columbia University in New York where he began working on designs for an atomic pile to create sustained chain reactions.
(The Making of the Atomic Bomb by Richard Rhodes, pp. 216-217)
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 98-99)
(http://www-history.mcs.st-and.ac.uk/Biographies/Fermi.html)

1938 | Lise Meitner

In 1938, Lise Meitner, a long time colleague of Otto Hahn was expelled from her position from the Kaiser Wilhelm Institute because of her partially Jewish Heritage. She and Hahn had been conducting experiments bombarding uranium with slowed streams of purified neutrons. Meitner maintained her scientific connection with Otto Hahn in her exile. Hahn had been bombarding the uranium atom with neutrons and mistook the results for a rise of barium residue, which he could not explain. In fact, Hahn and his student Fritz Strassman had actually split the uranium atom and transformed it into lighter elements much further up on the periodic table. After revealing his results to Meitner, she realized that the uranium atom had become unstable and burst because it was overstuffed with protons and neutrons. Hahn had cracked a uranium atom in half through the process of “fission” without even knowing it. This reinforced Niels Bohr’s liquid drop model of the atom. Like a balloon overfilled with water and then squeezed at the center, a uranium atom receiving additional neutrons wobbled, snapped and separated into two smaller and lighter nuclei Barium and Krypton whose combined atomic weight (56+36=92) was equal to uranium. The fission of the uranium atom had also released an enormous amount of energy relative to the splitting of a single atom - enough energy to make a grain of sand move. The findings of Meitner, Hahn and Strassman were published in German and British Journals. The atom was now open.
(The Making of the Atomic Bomb by Richard Rhodes, pp. 216-217)
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 98-99)
(Spying on the Bomb by Jeffrey T. Richelson, pp.19)

1939 | Albert Einstein

1939 Albert Einstein was now living in New Jersey and summered on the East End of Long Island after his exodus from Europe. He was familiar with the theoretical work of Enrico Fermi and Leo Szilard and became informed of the experiments conducted by Otto Hahn’s team at the Kaiser Wilhelm Institute as well as Lise Meitner’s perceptive interpretation of Hahn’s experiments. He now knew that his theory of relativity was beginning to be applied in experimental physics. After meeting with both Tellar and Szilard on these recent developments by Nazi German, he wrote U.S. President Roosevelt in August of 1939 warning him of the inevitable possibility of splitting atoms to create bombs. Some accounts suggest the letter was initially drafted by Leo Szilard. The White house politely responded to the now famous Einstein, but FDR and his cabinet found it unlikely that a super bomb was possible. The letter and the assignment for U.S. atomic bomb development found its way into the hands of Lyman J. Briggs; director of the government Bureau of Standards. Briggs did little to follow up on Einstein’s ominous warning. Being a man of the past he was comfortable with simpler times. In early 1940, Lisa Meitner’s nephew Robert Frisch lobbied to convinced Great Britain of the feasibility of constructing an atomic weapon. Briggs received a top-secret memo from England warning the U.S. He promptly locked the memo in his safe along with Einstein’s letter. This ignorance and oversight nearly cost America the atom bomb, World War II, and the end of free civilization on earth for future generations.
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 117-119)

~ Einstein's 1939 Letter to FDR

1939 | Enrico Fermi

In 1939, Enrico Fermi, began working on the problem of how to create a fission reaction on a large scale. Initially, it was thought that if one neutron had split one uranium atom than a large-scale release of energy would require large amounts of neutrons to split large amounts of uranium atoms. Fermi, as well as other physicists, began to suspect there was another way. Under the right conditions the two fragments resulting from a split atom might eject two or more “secondary” neutrons. These might be able to be used to split two more atoms which would result in four more secondary neutrons that could then split eight more atoms and so on. This process became known as a “chain reaction” a term borrowed from chemistry. If possible, the reaction would spread through a mass of uranium exponentially in a millionth of a second until the material went critical and released energy in the form of an explosion. It was estimated that eighty generations of such a reaction using one Kilogram of enriched uranium (a mass smaller than a baseball) would result in an explosion equivalent to 20,000 tons of TNT. Once this was realized, Fermi and his colleagues suggested the secondary neutron should be kept secret. Nevertheless, the findings were published and within a week physicists all over the world were making crude drawings for atomic bombs. However, creating a sustained chain reaction would prove to be much more difficult than simply enriching uranium ore.
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 119)
(Picturing the Bomb: Photographs from the Secret World of the Manhattan Project by Rachel Fermi & Esther Samra, p.13)

1940 | Werner Heisenberg

In 1940, Werner Heisenberg, the most famous German physicist of the era after Einstein, prepared a comprehensive report to Nazi Berlin in 1940 on how to build atomic bombs. He headed up the first attempts to build atomic reactors in Berlin and Leipzig. In contrast to the U.S., Nazi Germany’s government officials were initially very proactive in the prospects of developing atomic weapons. Joseph Goebbels noted in his diary “ Research in the realm of atomic destruction has now proceeded to a point where ...tremendous destruction...can now be wrought with minimal effort...it is now essential that we be ahead of everybody....” By this time Germany had annexed Czechoslovakia; which contained Europe’s largest mines of uranium ore. Heisenberg ordered large amounts of the raw material to begin his experiments. Armed with Fermi’s discovery of using slow neutrons to penetrate the nucleus of the atom, Heisenberg began searching for a method to accomplish this. He knew from Fermi’s early work that anything dense in hydrogen, even ordinary water, would work to some degree; but initial experiments with H2O yielded poor results. He then began using “heavy water” which is found in ordinary water in very minute amounts. Heavy water contains deuterium rather than hydrogen at the atomic level and is about twice as heavy. This increased density proved to be an excellent vehicle for slowing down neutrons. At first Heisenberg could only obtain small amounts of heavy water so his Experiments were not performed on a large scale and only instructed Leipzig to maximize the potential of the precious resource. He did however have access to nearly unlimited amounts of uranium and after several failed attempts his main experimenter Robert Dopel began to make progress. Even though the uranium being used was not purified enough to create a full chain reaction, by 1942 the first measurable releases of the trapped energy of the atom were occurring at a basement laboratory of the University of Leipzig in Nazi Germany.
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 126-129)

1940 | Emilio Serge & Glenn Seaborg

Emilio Serge and Glenn Seaborg had been following the slowed neutron work of Heisenberg and Fermi. Serge was a student of Enrico Fermi and Seaborg was a graduate student from Columbia University. The two young scientists began experimenting with various ways to transmute another radioactive material from uranium into a new isotope. They soon discovered that by bombarding uranium with alpha particles transmuted it into a new and unstable atomic substance with an atomic weight of 94, in very minute amounts. Further experiments revealed it might also be chemically extracted efficiently from uranium 239. Seaborg named the new isotope after the ninth planet of the solar system and the Greek god of the dead; Pluto. The highly radioactive and fissionable man made element came to be known as Plutonium.
(The Making of the Atomic Bomb by Richard Rhodes, pp. 350-355)

1941 | Albert Einstein

1941 Albert Einstein learned of Heisenberg’s progress from an exiled former director of the Kaiser Wilhelm Institute. Einstein wrote another letter to FDR to inform him of what he had learned. This time he did not even receive a reply. As the nation was now very close to war, the FBI was suspicious of Einstein’s socialist background and former ties to Germany. While Germany was working towards the creation of an atomic bomb, Lyman Briggs was relaxing at his desk smoking his pipe. By this time England was already at war with Germany and America was only involved in a supporting role providing Great Britain with arms and supplies. A British entourage arrived in Washington with a report on the feasibility of atomic weapons an important gift developed by one of Ernest Rutherford’s brightest students; Mark Oliphant. The gift was the cavity magnetron; a mechanism for reducing radar technology from a huge room-sized machine into device that could fit into an airplane. Oliphant and the British delegates learned of Briggs lazy pursuit of the atom bomb project and urgently pressured U.S. officials to push the project forward.
(E=mc2: A Biography of the World's Most Famous Equation by David Bodanis, pp. 131-133)

1941 | Vannevar Bush

Vannevar Bush, the Chairman of the National Resource Defense Committee (NRDC), which oversaw the uranium committee, was one of President Roosevelt’s top military science advisors. He brought the official British MAUD report to FDR in October of 1941 and persuaded him that the U.S. should pursue the program. Bush restructured the uranium committee and appointed Ernest Lawrence of the Berkeley Institute and Arthur H. Compton, a Nobel Prize winner in gamma radiation effects as project leaders. Lawrence had already built some of the world’s largest scientific machines and had worked extensively on the problem of separating enriched uranium U-235 from raw U-238 ore.
(Endless Frontier: Vannevar Bush, Engineer of the American Century by G. Pascal Zachary, pp. 198-199)

1941 | Ernest Lawrence & Arthur Compton

In 1941, Ernest Lawrence and Arthur Compton had began to focus on methods to practically manufacture plutonium in large quantities as another possible fuel for constructing atomic bombs. They began collaborating with Fermi and Szilard who were working on slowing neutrons with graphite to produce sustained chain reactions in “Piles” of stack enriched uranium. These piles eventually became the world’s first nuclear reactors. It was found that this process produced plutonium residue as a by-product that might be chemically separated from the used uranium. There were now four different practical methods for creating the fuel for atomic bombs; Enriched uranium by Centrifuge, Gaseous diffusion, Electromagnetic separation, and the use of plutonium from transmuted uranium by graphite or heavy water piles. The question now was which method would be pursued to reach that ultimate goal.
(The Making of the Atomic Bomb, by Richard Rhodes, pp. 394-406)

German Blitzkrieg (Lightning War) had overrun most of Europe by late 1941 and Hitler’s forces had advanced on Soviet Russia to within visual distance of Moscow. Then, the Russian winter set in and the advance came to a halt. The Russians counter attacked with one hundred divisions of fresh troops accustomed to bitter winter fighting. The German army was forced to retreat with approximately 1.2 million casualties. Germany had reached the limits of its expansion and would never fully recover from the rout by the Soviets. For the remainder of the war it would fight defensive lyon two fronts. Economic and military trade-offs would now be inevitable including the resources for an atomic weapons program.
(The Making of the Atomic Bomb, by Richard Rhodes, pp. 402-403)

1941 | Attack on Pearl Harbor

On December 7, 1941 The Japanese Navy attacked the U.S. Navel base at Pearl Harbor in Hawaii. A duel wave surprise attack of 350 planes from six aircraft carriers made a devastating blow on the U.S. Pacific fleet. In less than half an hour the raid destroyed eight battleships, three light cruisers, three destroyers and killed 2,403 Americans in hopes of crippling the U.S. Navy in the pacific region. Luckily, the U.S. Navy's aircraft carriers were not at Pearl Harbor and escaped the attack. President Roosevelt declared war on Japan the next day. Even at this time the U.S. government was still not fully committed to building an atom bomb. It was however, now committed to confirming the possibility of developing the weapon and began to push the project forward. The program became known as “The Manhattan Project” and finally took off under the authority of the Manhattan Engineering District agency. The program was ultimately placed under the command of U.S. Army Colonel Leslie Groves who had just completed supervising the construction the world’s largest building – the Pentagon. Nazi Germany had nearly a two-year head start on atomic weapons development and was home to the finest engineering community in the world. The U.S. and its allies were now at war with Nazi Germany and had offered sanctuary to most of Europe’s exiled top physicists due to the anti-semitic policies introduced by Adolph Hitler. The quest to acquire practical atomic weapons had begun.
(The Making of the Atomic Bomb, by Richard Rhodes, pp. 373-375)