This Day in History (2-Dec-1942) – Enrico Fermi Creates a Self-Sustaining Nuclear Chain Reaction for the Manhattan Project

American scientists, many of them refugees from fascist regimes in Europe, took steps in 1939 to organize a project to exploit the newly recognized fission process for military purposes. In the summer of 1939, Albert Einstein was persuaded by his fellow scientists to use his influence and present the military potential of an uncontrolled fission chain reaction to President Franklin D. Roosevelt. In February 1940, $6,000 was made available to start research. After the U.S. entry into the World war II, the War Department was given joint responsibility for the project. In June 1942 the Corps of Engineers’ Manhattan District was initially assigned management of the construction work (because much of the early research had been performed at Columbia University, in Manhattan). “Manhattan Project” became the code name for research work that would extend across the country.

Only method available for the production of the fissionable material plutonium-239, was developed at the metallurgical laboratory of the University of Chicago. In December 1942, Enrico Fermi, the Italian-born Nobel Prize-winning physicist, finally succeeded in producing and controlling a fission chain reaction in this reactor pile at Chicago.  Upon succesful completion of the experiment, a coded message was transmitted to President Roosevelt: “The Italian navigator has landed in the new world.”

The large-scale production reactors were built on an isolated tract on the Columbia River north of Pasco, Washington—the Hanford Engineer Works, for the quantity production of plutonium-239. By the summer of 1945, amounts of plutonium-239 sufficient to produce a nuclear explosion had become available from the Hanford Works, and weapon development and design were sufficiently far advanced so that an actual field test of a nuclear explosive could be scheduled. By this time the original $6,000 authorized for the Manhattan Project had grown to $2 billion. The first atomic bomb was exploded at 5:30 am on July 16, 1945, at a site on the Alamogordo air base 120 miles (193 km) south of Albuquerque, New Mexico, followed by Hiroshima and Nagasaki explosions in the next month.


This Day in History (21-Nov-1905) – Albert Einstein publishes a paper which was a precursor to the announcement of E = mc²

After reaching the lowest point of life at the age of 23 in 1902, with no job in hand, father going bankrupt, unable to marry girlfriend due to family pressure; Albert Einstein got a job in Swiss patent office in Bern, Switzarland. He quickly mastered the job, leaving him time to ponder on the transmission of electrical signals and electrical-mechanical synchronization, an interest he had been cultivating for several years. While at the school he had studied Scottish physicist James Maxwell’s electromagnetic theories which describe the nature of light, and discovered a fact unknown to Maxwell himself, that the speed of light remained constant. However, this violated Isaac Newton’s laws of motion because there is no absolute velocity in Newton’s theory. This insight led Einstein to formulate the principle of relativity.

In 1905—often called Einstein’s “miracle year”—he submitted a paper for his doctorate and had four papers published in the Annalen der Physik, one of the best known physics journals. The four papers—the photoelectric effect, Brownian motion, special relativity, and the equivalence of matter and energy—would alter the course of modern physics and bring him to the attention of the academic world. In his paper on matter and energy, Einstein deduced the well-known equation E=mc2, suggesting that tiny particles of matter could be converted into huge amounts of energy, foreshadowing the development of nuclear power.

At first, Einstein’s 1905 papers were ignored by the physics community. This began to change when he received the attention of Max Planck, perhaps the most influential physicist of his generation and founder of quantum theory. With Planck’s complimentary comments and his experiments that confirmed his theories, Einstein was invited to lecture at international meetings and he rose rapidly in the academic world. He was offered a series of positions at increasingly prestigious institutions, including the University of Zürich, the University of Prague, the Swiss Federal Institute of Technology, and finally the University of Berlin, where he served as director of the Kaiser Wilhelm Institute for Physics from 1913 to 1933.


This Day in History (20-Mar-1916) – Albert Einstein publishes his general theory of relativity

Two objects exert a force of attraction on one another known as “gravity.” Sir Isaac Newton quantified the gravity between two objects when he formulated his three laws of motion. Yet Newton’s laws assume that gravity is an innate force of an object that can act over a distance. In 1905, Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers. This was the theory of special relativity. As a result, he found that space and time were interwoven into a single continuum known as space-time. Events that occur at the same time for one observer could occur at different times for another.

Einstein then spent ten years trying to include acceleration in the theory and published his theory of general relativity in 1915. In it, he determined that massive objects cause a distortion in space-time, which is felt as gravity. Einstein proposed that objects such as the sun and the Earth change the geometry. In the presence of matter and energy it can evolve, stretch and warp, forming ridges, mountains and valleys that cause bodies moving through it to zigzag and curve. So although Earth appears to be pulled towards the sun by gravity, there is no such force. It is simply the geometry of space-time around the sun telling Earth how to move.

Although instruments can neither see nor measure space-time, several of the phenomena predicted by its warping have been confirmed. Light around a massive object, such as a black hole, is bent, causing it to act as a lens for the things that lay behind it. Astronomers routinely use this method to study stars and galaxies behind massive objects. Einstein’s Cross, a quasar in the Pegasus constellation, is an excellent example of gravitational lensing. The quasar is about 8 billion light-years from Earth, and sits behind a galaxy that is 400 million light-years away. Four images of the quasar appear around the galaxy because the intense gravity of the galaxy bends the light coming from the quasar. The general theory of relativity also explains the motion of the planets and can also describe the history and expansion of the universe.