February
Important historic dates in science

February 28: Steven Chu
(Born February 28, 1948)
American physicist who (with Claude Cohen-Tannoudji and William D. Phillips) was awarded the 1997 Nobel Prize for Physics for their independent, pioneering research in cooling and trapping atoms using laser light. In their normal state the constant random thermal motion of atoms limits the precision of measurements of atomic states. Thus, physicists have sought to cool and slow atoms down as much as possible. Chu used six laser beams and worked with a hot gas of sodium atoms. He managed to cool and trap atoms in what he called "optical molasses." By 1985, he had cooled sodium atoms to a temperature of about 240 millionth of a degree above absolute zero. The atoms could be trapped in the laser beams for a period of about half a second.

February 27: Neutron
In 1932, the neutron was discovered by Dr. James Chadwick.

February 26: Radioactivity
In 1896, Henri Becquerel stored a phosphorescent uranium compound in a closed desk drawer on top of a photographic plate awaiting a sunnier day to test his idea that sunlight would make the phosphorescent uranium emit rays. It remained there several days. Thus by accident, he created a new experiment, for when he developed the photographic plate, he found a fogged image in the shape of the rocks. The material was spontaneously generating and emitting the energetic rays totally without the external sunlight source. This was a landmark event. The new form of penetrating radiation was the discovery of the effect of radioactivity.

February 25: Ida Noddack
(Born February 25, 1896: Died 1979)
German chemist who co-discovered (1925) element 75, rhenium, which they named after the Rhine River. They found trace amounts in the mineral columbite. She was working with Walter Noddack, her future husband (1926). They were also trying to find element 43, which they called masurium, but announcement of that find was mistaken. She commented on the possibility of fission upon hearing the reports of Fermi's 1934 observations of the neutron bombardment of uranium. Her idea remained dormant. However, when Frisch, five years afterwards, presented the same idea, it became accepted. In photochemistry, the Noddacks worked on sensitizing coloring substances, the photochemistry of the human eye and other subjects.

February 24: Uranium
In 1896, Henri Bequerel told the French Academy of Sciences of his investigation of the phosphorescent rays of some "double sulfate of uranium and potassium" crystals. He reported that he placed the crystals on the outside of a photographic plate wrapped in sheets of very thick black paper and exposed the whole to the sun for several hours. When he developed the photographic plate, he saw a black silhouette of the substance exposed on the negative. When he placed a coin or metal screen between the uranium crystals and the wrapped plate, he saw images of those objects on the negative. He does not know yet that he has accidentally discovered radioactivity, or that the sun is not necessary to initiate the rays.

February 23: Allan MacLeod Cormack
(Born February 23, 1924: Died May 7, 1998)
South African-born American physicist who formulated the mathematical algorithms that made possible the development of a powerful new diagnostic technique, the cross-sectional X-ray imaging process known as computerized axial tomography (CAT) scanning. He first described this in two papers in 1963 and 1964. X-ray tomography is a process by which a picture of an imaginary slice through an object (or the human body) is built up from information from detectors rotating around the body. For this work, he was awarded a share of the 1979 Nobel Prize. Cormack was unusual in the field of Nobel laureates because he never earned a doctorate degree in medicine or any other field of science.

February 22: First English clinical radiology report
In 1896, the first use of clinical radiology in England was reported in The Lancet by Charles Thurstan Holland only a few months after Roentgen's announcement of their properties. Holland had been in attendance on February 7, 1896 when the wrist of a 12-year-old boy, who had shot himself the previous month, was examined in the laboratory of Oliver Lodge, head of the physics department at Liverpool University. The boy had been brought there by surgeon Sir Robert Jones when probing alone could not locate the bullet. Using X-rays, the pellet was identified embedded in the third carpo-metacarpal joint. Jones subsequently financed an X-ray apparatus for Holland to pioneer radiology at Royal Southern Hospital, Liverpool. [Image: X-ray from 1896 of hand with buckshot made at Columbia University, USA]

February 21: George Ellery Hale
(Born June 29, 1868: Died February 21, 1938)
American astronomer known for his development of important astronomical instruments. To expand solar observations and promote astrophysical studies he founded Mt. Wilson Observatory (Dec 1904). He discovered that sunspots were regions of relatively low temperatures and high magnetic fields. Hale hired Harlow Shapley and Edwin Hubble as soon as they finished their doctorates, and he encouraged research in galactic and extragalactic astronomy as well as solar and stellar astrophysics. Hale planned and tirelessly raised funds for the 200" reflecting telescope at the Palomar Mountain Observatory completed in 1948, after his death, and named for him - the Hale telescope.

February 20: Maric Goeppert Mayer
(Born June 28, 1906: Died February 20, 1972:
German physicist who shared one-half of the 1963 Nobel Prize for Physics with J. Hans D. Jensen of West Germany for their proposal of the shell nuclear model. (The other half of the prize was awarded to Eugene P. Wigner of the United States for unrelated work.) In 1939 she worked at Columbia University on the separation of uranium isotopes for the atomic bomb project. In 1949, she devised the shell nuclear model, which explained the detailed properties of atomic nuclei in terms of a structure of shells occupied by the protons and neutrons. This explained the great stability and abundance of nuclei that have a particular number of neutrons (such as 50, 82, or 126) and the same special number of protons.

February 19: Nicolaus Copernicus
(Born February 19, 1473: Died May 24, 1543)
Polish astronomer who proposed that the planets have the Sun as the fixed point to which their motions are to be referred; that the Earth is a planet which, besides orbiting the Sun annually, also turns once daily on its own axis; and that very slow, long-term changes in the direction of this axis account for the precession of the equinoxes.

February 18: J. Robert Oppenheimer
(Born April 22, 1904: Died February 18, 1967)
Julius Robert Oppenheimer was a U.S. theoretical physicist and science administrator, noted as director of the Los Alamos laboratory during development of the atomic bomb (1943-45) and as director of the Institute for Advanced Study, Princeton (1947-66). Accusations as to his loyalty and reliability as a security risk led to a government hearing that resulted the loss of his security clearance and of his position as adviser to the highest echelons of the U.S. government. The case became a cause célèbre in the world of science because of its implications concerning political and moral issues relating to the role of scientists in government.

February 17: British atomic bomb announced
In 1952, Winston Churchill announced that Britain had developed its own atomic bomb. The test for the first British-made atomic bomb was planned at the Monte Bello Islands off the northwest coast of Australia. The formal postwar decision to manufacture a British atomic bomb had been made by Prime Minister Clement Attlee's government early in January, 1947 during a meeting of the Defence Subcommittee of the Cabinet. On February 25, 1952 at Sellafield on the Irish Sea coast in Cumberland, the Windscale plutonium plant began operation. On October 3, 1952 the first British atomic weapons test, called Hurricane, was successfully conducted aboard the frigate HMS Plym. Britain was was the third nuclear power after the U.S. and Russia to include the atomic bomb in its armoury.

February 16: Nuclear tests
1977 - USSR performs nuclear test at Sary Shagan USSR
1966 - France performs underground nuclear test at Ecker, Algeria

February 15: Herman Kahn
(Born February 15, 1922: Died July 7, 1983)
American physicist, military analyst (1948-61) and futurist best known for his controversial studies of nuclear warfare. Kahn won recognition for his dispassionate analysis of nuclear war in his books On Thermonuclear War (1960) which still, in its detached analysis of various nuclear-war scenarios, retains the power to shock.and Thinking About the Unthinkable (1962) which predicted the probability and survivability of nuclear war. Later books included the optimistic The Year 2000 (1967) and Why ABM? (1969). In 1961 he founded the influential Hudson Institute in New York to make reasoned predictions on world affairs, from narcotics policy to global economics, energy, international trade, population, transportation, crime, medicine.

February 14: Walter Henry Zinn
(Born December 10, 1906: Died February 14, 2000)
Canadian-American nuclear physicist who contributed to the U.S. atomic bomb project during World War II and to the development of the nuclear reactor. He collaborated with Leo Szilard, investigating atomic fission. In 1939, they demonstrated that uranium underwent fission when bombarded with neutrons and that part of the mass was converted into energy (given by E = mc2). This work led him into research into the construction of the atomic bomb during WW II. After the war Zinn started the design of an atomic reactor and, in 1951, he built the first breeder reactor. In a breeder reactor, the core is surrounded by a "blanket" of uranium-238 and neutrons from the core convert this into plutonium-239, which can also be used as a fission fuel.

February 13: French atomic bomb
In 1960, France detonated their first plutonium bomb from a 330-foot tower at the Reggane base in the Sahara in what was then French Algeria. On October 18, 1945, the Atomic Energy Commission (Commissariat à l'Énergie Atomique; CEA) had been established by General Charles de Gaulle with the objective of exploiting the scientific, industrial, and military potential of atomic energy. On July 22, 1958, de Gaulle, having resumed power as prime minister, had set the date for the first atomic explosion to occur within the first three months of 1960. His goal was to assert France's independence and its role on the world stage. Thus he set about building the country's nuclear capacity acquiring also nuclear-armed aircraft, missiles and submarines.

February 12: Pierre-Louis Dulong
(Born February 12, 1785: Died July 18, 1838)
chemist and physicist who helped formulate the Dulong-Petit law of specific heats (1819), which proved useful in determining atomic weights.

February 11: Atomic fission
In 1939, the journal Nature published a theoretical paper on nuclear fission. The term was coined by the authors Lise Meitner and Otto Fritsch, her nephew. They knew that when a uranium nucleus was struck by neutrons, barium was produced. Seeking an explanation, they used Bohr's "liquid drop" model of the nucleus to envision the neutron inducing oscillations in a uranium nucleus, which would occasionally stretch out into the shape of a dumbbell. Sometimes, the repulsive forces between the protons in the two bulbous ends would cause the narrow waist joining them to pinch off and leave two nuclei where before there had been one. They calculated calculated the huge amounts of energy released. This was the basis for nuclear chain reaction.

February 10: Wilhelm Conrad Röntgen
(Born May 27, 1845: Died February 10, 1923)
(also spelled Roentgen) German physicist who was a recipient of the first Nobel Prize for Physics, in 1901, for his discovery of X rays, which heralded the age of modern physics and revolutionized diagnostic medicine.

February 9: Japanese nuclear accident
In 1991, Japan's worst nuclear accident happened at Mihama. A pipe in the steam generator burst, leaking 55 tonnes of radioactive primary (reactor) coolant water into the secondary steam-generating circuit. Some radioactivity was released to the atmosphere and the plant's emergency core cooling system was activated. MITI reported later that the accident was caused by human error, some anti-vibration bars being wrongly installed by workers and sawn off short to make them fit. The release of radiation into the atmosphere was kept to a small amount. No deaths resulted. Various measures were taken to prevent the recurrence of the accident, including the replacement of the steam generators.

February 8: Walther Bothe
(Born January 8, 1891: Died February 8, 1957)
Walther Wilhelm Georg Bothe was a German physicist who developed the coincidence method of detecting the emission of electrons by x-rays in which electrons passing through two adjacent Geiger tubes at almost the same time are registered as a coincidental event. He used it to show that momentum and energy are conserved at the atomic level. In 1929 he applied the method to the study of cosmic rays and was able to show that they consisted of massive particles rather than photons. This research brought him a share (with Max Born) in the Nobel Prize for 1954. In 1930, he observed a strange radiation emitted from beryllium when it was exposed to alpha particles, later identified by Chadwick as consisting of neutrons. He built Germany's first cyclotron (1943).

February 7: Igor Vasilyevich Kurchatov
(Born January 12, 1903: February 7, 1960)
Soviet nuclear physicist who was appointed director of nuclear physics at the Leningrad Institute in 1938, then guided the development of his country's first atomic bomb (1949), the world's first practical thermonuclear bomb (1952), and the first atomic electric-power station in the Soviet Union (1946). Before 1978, element-104 was known in the Soviet Union as kurchatovium (Ku). The American claimants to the discovery named it rutherfordium (Rf), which is now the accepted name.

February 6: Edward Emerson Barnard
(Born December 16, 1857: Died February 6, 1923)
Astronomer who pioneered in celestial photography, specializing in wide-field photography. From the time he began observing in 1881, his skill and keen eyesight combined to make him one of the greatest observers. Barnard came to prominence as an astronomer through the discovery of numerous comets. In the 1880s, a patron of astronomy in Rochester, N.Y. awarded $200 per new comet was found. Barnard discovered eight - enough to build a "comet house" for his bride. At Lick Observatory (1888-95) he made the first photographic discovery of a comet; photographed the Milky Way; and discovered the fifth moon of Jupiter. Then he joined Yerkes Observatory, making his Photographic Atlas of Selected Regions of the Milky Way.

February 5: Robert Hofstadter
(Born February 5, 1915: Died November 17, 1990)
American scientist who was a joint recipient of the Nobel Prize for Physics in 1961 for his investigations in which he measured the size of the neutron and proton in the nuclei of atoms. He revealed the hitherto unknown structure of these particles and helped create an identifying order for subatomic particles. He also correctly predicted the existence of hte omega-meson and rho-meson. He also studied controlled nuclear fission. Hofstadter was one of the driving forces behind the creation of the Stanford Linear Accelerator. He also made substantial contributions to gamma ray spectroscopy, leading to the use of radioactive tracers to locate tumors and other disorders. (He shared the prize with Rudolf Ludwig Mössbauer of Germany.)

February 4: Satyendra Nath Bose
(Born January 1, 1894: Died February 4, 1974)
Indian mathematician and physicist who collaborated with Albert Einstein to develop a theory of statistical quantum mechanics, now called Bose-Einstein statistics. In his early work in quantum theory (1924), Bose had derived the Planck black-body radiation law, without reference to classical electrodynamics. Einstein extended this technique to integral spin particles. Dirac coined the name boson for particles obeying these statistics. Bose also worked on X-ray diffraction and the interaction of electromagnetic waves with the ionosphere.

February 3: Paul Scherrer
(Born February 3, 1890: Died September 25, 1969)
Swiss physicist who collaborated with Peter Debye in the development of a method of X-ray diffraction analysis. The Debye-Scherrer method is widely used to identify materials that do not readily form large, perfect crystals.

February 2: Nuclear test
The United States performs nuclear test at Nevada Test Site, in 1951.

February 1: Atomic bomb explosion and Moving X-Ray pictures
In 1951, the TV station KTLA broadcast of an atomic explosion was the first to be seen publicly on television. The event was captured by an NBC camera on Mount Wilson, 300 miles away from the test blast at Frenchman Flats, Nevada. Also, In 1951, the first X-ray moving picture process was demonstrated.

Click here to see previous months:
January

Photos courtsey of Today in Science