Important historic dates in science

August 31: Friedrich Adolf Paneth
(Born August 31, 1887: Died September 17, 1958)
Austrian chemist who with George Charles de Hevesy introduced radioactive tracer techniques (1912-13). After using radium D as a tracer in determining the solubility of lead salts, Paneth went on to use the technique for studying the unstable hydrides of lead and bismuth. During the 1920's he studying methods to measure in rocks the trace amounts of helium (which is slowly liberated by the radioactive decay of uranium). This work not only made it possible to determine the age of rocks on earth, but also meteorites, which was an important step towards determining the age of the solar system, presently accepted as 4,600 million years.

August 30: Wilhelm Wien
(Born January 13, 1864: August 30, 1928)
German physicist who received the Nobel Prize for Physics in 1911 for his displacement law concerning the radiation emitted by the perfectly efficient blackbody (a surface that absorbs all radiant energy falling on it). While studying streams of ionized gas Wien, in 1898, identified a positive particle equal in mass to the hydrogen atom. Wien, with this work, laid the foundation of mass spectroscopy. J J Thomson refined Wien's apparatus and conducted further experiments in 1913 then, after work by E Rutherford in 1919, Wien's particle was accepted and named the proton. Wien also made important contributions to the study of cathode rays, X-rays and canal rays.

August 29: USSR's first atomic bomb
In 1949, the USSR tested their first atomic device, "First Lightning." It was an an implosive type plutonium bomb, detonated at the Semipalatinsk test range, giving up to a 20 kiloton yield. In the U.S. it was called Joe No. 1 ("Joe" was nickname for Y. Stalin.) This event came five years earlier than anyone in the West had predicted, largely due to one man, the spy Klaus Fuchs. As a Los Alamos physicist, Fuchs had passed detailed blue prints of the original American Trinity bomb design to the Russians. With the emergence of the USSR as a nuclear rival, America's monopoly of atomic weaponry was ended giving the U.S. strong motivation for intensifying its program of nuclear testing. Thus the Cold War was launched.

August 28: Sir Godfrey Newbold Hounsfield
(Born August 28, 1919: Died August 12, 2004)
English electrical engineer who shared the 1979 Nobel Prize for Physiology or Medicine (with independent worker Allan Cormack) for developing computerized axial tomography (CAT). In CAT, a high-resolution x-ray picture of an imaginary slice through the body (or head) is built up from information taken from detectors rotating around the patient. These 'scanners' allow delineation of very small changes in tissue density. Introduced in 1973, early machines were used to overcome obstacles in the diagnosis of diseases of the brain, but the technique has now been extended to the whole body. He worked for EMI from 1951 and led the design effort for Britain's first large solid-state computer. Later he worked on problems of pattern recognition. Although he had no formal university education he was granted an honorary doctorate in medicine by the City University, London (1975).

August 27: Norman Foster Ramsey
(Born August 27, 1915)
American physicist who received one-half of the Nobel Prize for Physics in 1989 for his development of a technique to induce atoms to shift from one specific energy level to another. (The other half of the prize was awarded to Wolfgang Paul and Hans Georg Dehmelt.) Ramsey's innovation was called the separated oscillatory fields method.

August 26: Fredrick Reines
(Born March 16, 1918: Died August 26, 1998)
American physicist who was awarded the 1995 Nobel Prize for Physics for his detection in 1956 of neutrinos, working with his colleague Clyde L. Cowan, Jr. The neutrino is a subatomic particle, a tiny lepton with little or no mass and a neutral charge which had been postulated by Wolfgang Pauli in the early 1930s but had previously remained undiscovered. (Reines shared the Nobel Prize with physicist Martin Lewis Perl, who discovered the tau lepton.)

August 25: Antoine-Henri Becquerel
(Born December 15, 1852: Died August 25, 1908)
French physicist who discovered radioactivity through his investigations of uranium and other substances. In 1903 he shared the Nobel Prize for Physics with Pierre and Marie Curie. His early researches were in optics, then in 1896 he accidentally discovered radioactivity in fluorescent salts of uranium. He left a plate in black paper next to some crystals in a drawer and some time later developed the plate. He found that this too was fogged, even though the crystals were not fluorescing - and that the salt gave off a penetrating radiation independently, without ultraviolet radiation. Three years later he showed that it consists of charged particles that are deflected by a magnetic field. Initially, the rays emitted by radioactive substances were named after him.

August 24: French H-bomb
In 1968, France exploded a hydrogen bomb over a South Pacific testing ground and became the world's fifth thermonuclear power. The Canopus test used a 3 tonne device suspended at an altitude of 600 m from a balloon over Fangataufa Atoll, 41 km south east of Moruroa. The project was led by a young physicist, Roger Dautry.This was France's largest nuclear device. It produced a yield of 2.6 megatons, and used a lithium-6 deuteride secondary jacketed with highly enriched uranium. The resulting contamination of the atoll kept it off limits to humans for six years, after which France resumed their nuclear program there with underground tests.

August 23: Auguste Bravais
(Born August 23, 1811: Died March 30, 1863)
French physicist and mineralogist, best remembered for his work on the lattice theory of crystals. Bravais lattices are named for him. In 1850, he showed that crystals could be divided into 14 unit cells for which: (a) the unit cell is the simplest repeating unit in the crystal; (b) opposite faces of a unit cell are parallel; and (c) the edge of the unit cell connects equivalent points. These unit cells fall into seven geometrical categories, which differ in their relative edge lengths and internal angles. In 1866, he elaborated the relationships between the ideal lattice and the material crystal. Sixty years later, Bravais' work provided the mathematical and conceptual basis for the determination of crystal structures after Laue's discovery of X-ray diffraction in 1911.

August 22: Nuclear ship
In 1962, The Savannah, the world's first nuclear-powered ship, completed her maiden voyage from Yorktown, Va., to Savannah, Ga.

August 21: Jean Servais Stas
(Born August 21, 1813: Died December 13, 1891)
Belgian chemist, notable for his accurate determinations of atomic weights. He had worked under the direction of Dumas, with whom he established the atomic weight of carbon. Stas worked assiduously to make more accurate measurements of other atomic weights than had ever been done before. Stas wished to prove the hypothesis of Proust, that all atoms were conglomerations of hydrogen atoms, though this could not be achieved. Stas was probably the most skilful chemical analyst of the nineteenth century.

August 20: Soviet H-bomb
In 1953, the Soviet Union publicly acknowledged it had tested a hydrogen bomb.

August 19: Philo Farnsworth
I(Born August 19, 1906: Died March 11, 1971)
An American inventor who was the first to demonstrate and patent a working electronic television system.

August 18: Bern Dibner
(Born August 18, 1897: Died January 6, 1988)
Ukrainian-American engineer and historian of science. Dibner worked as an engineer during the electrification of Cuba. Realizing the need for improved methods of connecting electrical conductors, in 1924, he founded the Burndy Engineering Company. A few years later, he became interested in the history of Renaissance science. Subsequently, he began collecting books and everything he could find that was related to the history of science. This became a second career as a scholar that would run parallel with his life as a businessman. He wrote many books and pamphlets, on topics from the transport of ancient obelisks, to authorative biographies of many scientific pioneers, including Volta, inventor of the electric battery, and Roentgen, discoverer of the X ray.

August 17: Otto Stern
(Born February 17, 1888: Died August 17, 1969)
German-born scientist and winner of the Nobel Prize for Physics in 1943 for his development of the molecular beam as a tool for studying the characteristics of molecules and for his measurement of the magnetic moment of the proton.

August 16: Robert Bunsen
(Born March 31, 1811: Died August 16, 1899)
German chemist who, with Gustav Kirchhoff, about 1859 observed that each element emits a light of characteristic wavelength. (These studies opened the field of spectrum analysis, important in the study of the Sun and stars.) With this tool, Bunsen soon discovered two new elements: cesium and rubidium. He developed several techniques used in separating, identifying, and measuring various chemical substances. He also made a number of improvements in chemical batteries for use in isolating quantities of pure metals, (one is known as the Bunsen battery). His Bunsen burner was created for use in flame tests of various metals and salts because its nonluminous flame did not interfere with the colored flame given off by the test material.

August 15: Lowest temperature ever
In 1994, the National Institute of Standards and Technology (NIST) issued a press release that physicists there recently cooled atoms to 700 nanokelvins, the coldest temperature ever recorded for matter. NIST scientists chilled a cloud of cesium atoms very close to absolute zero using lasers to catch the atoms in an optical lattice. The atoms reached 700 nanokelvins, or 700 billionths of a degree above absolute zero. Zero kelvin (-273ºC), or absolute zero, is the temperature at which atomic thermal motion would cease. Since the late 1970s, physicists have sought to use lasers to cool atoms closer to absolute zero, primarily for improving atomic timekeeping, certain experimental measurements and lithography processes for the semiconductor industry.

August 14: Frederic Joliot-Curie
(Born March 19, 1900: Died August 14, 1958)
French physical chemist, husband of Irène Joliot-Curie, who were jointly awarded the 1935 Nobel Prize for Chemistry for their discovery of artificially prepared, radioactive isotopes of new elements. They were the son-in-law and daughter of Nobel Prize winners Pierre and Marie Curie.

August 13: Helium ions from radium
In 1903, the journal Nature reported that helium gas is produced by the radioactive decay of the radium. This key discovery by William Ramsay and Frederick Soddy helped to reveal the structure of atoms. In 1908, Rutherford confirmed that alpha rays and these radium emanations were one and the same: the nuclei of helium atoms, bearing a positive electrical charge. Each were future Nobel laureates in Chemistry. Ramsey won the Nobel Prize in 1904 for his discovery of the noble gases. Rutherford was recognized in 1908 for his investigations into the disintegration of the elements. Soddy was honored in 1921 for his pioneering contributions to understanding the chemical properties of radioactive elements such as radium and uranium.

August 12: Soviet H-bomb
In 1953, the Soviet Union detonated its first hydrogen bomb, in Kazakhstan, less than a year after President Harry Truman announced on January 7, 1953 that the United States had developed a hydrogen bomb. The USSR press published the news of its first hydrogen bomb on January 20, 1953. Its yield, equivalent of 400 kilotons of TNT was about 30 times larger than the atomic bomb dropped on Hiroshima. The USSR device used a "Layer Cake" design, was small enough to fit in a plane, and could easily be turned into a deliverable weapon. Its size restricted the amount of thermonuclear fuel and explosive force, in contrast with the American thermonuclear device, "Mike," tested November 1, 1952 which was designed for great explosive power.

August 11: Macedonio Melloni
(Born April 11, 1798: Died August 11, 1854)
Italian physicist who was the first to extensively research infrared radiation. After Herschel's earlier discovery of infrared radiation a generation before, suitable tools were lacking until the invention of a thermopile in 1830. That instrument was a series of strips of two different metals that produced electric current when one end was heated. Melloni improved the thermopile and used it to detect infrared radiation. In 1846, from an observation point high on Mount Vesuvius, he measured the slight heating effect of moonlight. He showed also that rock salt, being transparent to infrared, made suitable lenses and prisms to demonstrate the reflection, refractioin, polarization and interference of infrared in the same manner as visible light.

August 10: Henry Gwyn Jeffreys Moseley
(Born November 23, 1887: Died August 10, 1915)
English physicist who experimentally demonstrated that the major properties of an element are determined by the atomic number, not by the atomic weight, and firmly established the relationship between atomic number and the charge of the atomic nucleus.

August 9: Ralph Wyckoff
(Born August 9, 1897: Died November 3, 1994)
Ralph (Walter Graystone) Wyckoff was an American scientist, a pioneer in the application of X-ray methods to determine crystal structures and one of the first to use these methods for studying biological substances. He became famous in two areas of structural research: X-ray diffraction and electron microscopy. He developed a new technique of 'metal shadowing' for observation with the electron microscope. A specimen, such as a virus, is placed in a vacuum together with a heated tungsten filament covered with gold. Vaporized gold coated the side of the specimen nearest the filament, leaving a 'shadow' on the far side. This allowing better estimates to be made of their size and shape, as well as revealing details of their structure.

August 8: Atomic energy conference
In 1955, Geneva conference held to discuss peaceful uses of atomic energy.

August 7: Bart J. Bok
(Born April 28, 1906: Died August 7, 1983)
Bok was an astronomer, expert on the Milky Way Galaxy and for his study of "Bok globules," small dark clouds observable against the background of bright nebulae. Bok suggested that these globules may be condensed clouds of interstellar gas and dust in the process of contracting into stars.

August 6: Atomic Bomb
In 1945, during World War II, an atomic bomb was dropped on Hiroshima, Japan, by The Unnited States.

August 5: Quasar
In 1962, a lunar occultation on August 5 enabled Australian radio astronomers to more precisely fix the location of the previously known radio source 3C 273, in Virgo. In 1963 this became the first member of a new class of object eventually to be called quasars or "quasi-stellar radio sources." Maarten Schmidt, using the Hale optical telescope, saw it as a faint star-like object with a visible jet. Its spectrum featured unusual emission lines, which he identified as ordinary hydrogen lines shifted toward longer wavelengths (redshifted) by 16%. If the shift is due to velocity, it is moving away at one-sixth the speed of light and one of the most distant objects visible. Quasars radiate as much energy per second as a hundred or more galaxies. 3C273 is the brightest quasar known.

August 4: UK supersonnic fighter
In 1954, Britain's first supersonic fighter plane, the P-1 English Electric Lightning, made its maiden flight.

August 3: Edison on radium emanations
In 1903, Thomas Edison's opinion of radium was quoted within an article in the New York World newspaper. "I have had several pieces of it from Mme. Curie in Paris, and I have experimented with it. I do not see its commercial utility, but it opens up a great field of thought and scientific research. It overturns all the old theories of force and energy... I have a peculiar theory about radium, and I believe it is the correct one. I believe that there is some mysterious ray pervading the universe that is fluorescing to it. In other words, that all its energy is not self-constructed but that there is a mysterious something in the atmosphere that scientists have not found that is drawing out those infinitesimal atoms and distributing them forcefully and indestructibly."

August 2: John Tyndall
(Born: August 2, 1820; Died: December 4, 1893)
Irish physicist who became known to the scientific world in 1848 as the author of a substantial work on Crystals. In 1856 he traveled with Professor Huxley to Switzerland, after which he co-authored On the Structure and Motion of Glaciers. He also published Heat as a Mode of Motion (1863), On Radiation (1865), followed by Sound, then in 1870 he published Light. Included in these works were studies of acoustic properties of the atmosphere and the blue colour of the sky, which he suggested was due to the scattering of light by small particles of water.

August 1: X-ray
In 1934, the first X-ray photograph of the whole body taken in a one-second exposure, using ordinary clinical conditions such as would exist at an average hospital, was made at Rochester, N.Y. The one-piece radiograph was made by Arthur W. Fuchs of the Eastman Kodak Company. A selective filter was used for the first time, and the film size was 32"x72". It was exhibited by the Chicago Roentgen Society at the Century of Progress Exhibition in Chicago, Illinois.

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Photos courtsey of Today in Science