| 1781 |
[United Kingdom] Planet Uranus; discovery by William Herschel. (see uranium) |
| 1789 |
[Germany] Element Uranium discovered by Martin Heinrich Klaproth.(Utilized
as a glass-coloring agent.) |
| 1828 |
[Sweden] Element Thorium discovered by Jons Jakob Berzlius. Named from
Norse god of thunder, "Thor". Utilized as a mantle for gas lights. |
| 1846.6 |
[France] Planet Neptune discovered by J.Galle. (see neptunium) |
| 1873 |
[United Kingdom] "Treatise on Electricity and Magnetism "published by
James Clerk Maxwell, of Cavendish Laboratory. |
| 1885 |
[Switzerland] Balmer series in spectrum of the hydrogen atom and the Balmer
equation on spectrum series by Johann Jakob Balmer. |
| 1890 |
[Sweden] Rydberg equation by Johannes Robert Rydberg. (Rydberg constant
used in spectroscopy) |
| 1895.11.8 |
[Germany] X-ray discovered by Wilhelm Conrad Roentgen. (Received 1901 Nobel
prize.) |
| 1896.3.1 |
[France] Radioactivity discovered by Henri Becquerel due to darkening of
a photographic dry plate by a uranium compound. Named "radioactivity"by
Marie Curie. (Received 1903 Nobel prize.) |
| 1897 |
[Netherlands] Zeeman effect discovered by Pieter Zeeman. Separation of spectral
lines in magnetic field. (Received 1902 Nobel prize.) |
| 1897 |
[United Kingdom] Electron's existence verified by Joseph John Thomson at Cavendish
laboratory. (Received 1906 Nobel prize.) |
| 1898 |
[Canada] Alpha-ray and beta-ray discovered by Ernest Rutherford(Lord Nelson).
They were distinguished by different transmissibility. |
| 1898.12.26 |
[France] Radium and polonium discovered by Marie and Pierre Curie. Purified
from uranium ore, named for Poland. (Received 1903 Nobel prize.) Used prize
money to found the Radium Research Laboratory. |
| 1900.10.19 |
[Germany] Quantum theory of radiation presented by Max Karl Ernst Ludwig
Planck. |
| 1900 |
[France] Gamma-ray discovered by P.V.Villard. |
| 1900 |
[France] Beta-ray is cathode ray, proved by Henri Becquerel. |
| 1900 |
[Canada] Radioactive gas (called emanation) from thorium discovered by Ernest
Rutherford. |
| 1900 |
[France] Radioactive gas from radium discovered by Marie Curie. |
| 1900 |
[France] Radioactive gas from actinium. |
| 1903 |
[Canada] Theory of atomic decay and radioactivity presented by Ernest Rutherford
and Frederic Soddy. Transition of thorium to radon gas. Half life of radioactivity.
(Received 1908 Nobel prize.) |
| 1903 |
[Japan] Saturn model of atom presented by Hantarou Nagaoka. It does not
solve the problem of the stability of electron orbit. Nagaoka met with Rutherford
in 1911 but failed to get any his comments about the issue. |
| 1903.12.17 |
[U.S.A.] The first engine-powered airplane flown by Wright brothers in Kitty
Hawk, North Carolina. |
| 1905 |
[Germany] Special theory of relativity presented by Albert Einstein. Quantum
mechanism of photoelectric effect and photon. mass ＝energy,Ｅ＝ｍｃ2.
(Received 1921 Nobel prize.) |
| 1905 |
[Canada] Uniformity of alpha-ray mass discovered by Otto Hahn, a student
of Rutherford at McGill University, Montreal |
| 1906 |
[Canada] Scattering of alpha-ray;discovery by Ernest Rutherford. Refraction
of alpha-ray by mica indicating the existence of high electric field within
atom. (McGill University) |
| 1908 |
[United Kingdom] Geiger Counter; developed by Hans Geiger. Device for detecting
radioactivity. Geiger was a student of Rutherford at Manchester University. |
| 1908 |
[United Kingdom] Alpha-ray shown to be equivalent to helium nucleus by Ernest Rutherford
in the commemorative lecture of Nobel prize. |
| 1909 |
[United Kingdom] Detection of alpha-ray scattering by Ernest Marsden, a student
of Rutherford. Reflection of alpha-particle by 90 degree during passage
through gold foil. |
| 1911.3.7 |
[United Kingdom] Atomic nucleus proposed by Ernest Rutherford, not referring to
the Saturn model of Hantaro Nagaoka. |
| 1911.10.30 |
The First Solvay Meeting with Einstein,Plank,Lorenz,Poincare,Curie,Langevin,Rutherford.
On radioactivity and quantum theory. |
| 1911 |
[United Kingdom] Cloud chamber developed by Charles Thompson Rees Wilson. Detection
of flight course of ionic nucleus by cloud developed in supersaturated mixed
gas of argon and ethanol. At Cavendish Laboratory.(Received 1927 Nobel prize.) |
| 1911 |
[Austria] Cosmic rays verified by Victor Francis Hess measuring in a balloon
5 km high. (Received 1936 Nobel prize) |
| 1912 |
[United Kingdom] Radiothorium purified from barium compound by Otto Hahn. Later
identified as isotope of thorium. |
| 1912.11 |
[Germany] Diffraction of X rays found by Max Theodore Felixvon Laue. Irradiation
of crystallized zinc sulphate proving that x ray is an electromagnetic wave.
(Received 1914 Nobel prize.) |
| 1913.3.6 |
[Denmark] Planetary model of atomic structure presented by Niels Hendrik
David Bohr. Developed out of quantum theory. (Received 1922Nobel prize.) |
| 1913 |
[United Kingdom] Isotope concept presented by Frederick Soddy, a student of Rutherford.
(Received 1922 Nobel prize.) |
| 1913 |
[United Kingdom] Separation of neon isotope by Francis Aston utilizing a gaseous
diffusion method by repeating diffusion through china clay partition thousands
times. |
| 1913 |
[United Kingdom] The theory of X ray diffraction presented by William Henry and
William Lawrence Bragg, father and son. (Received 1915 Nobel prize.) |
| 1913.11 |
[United Kingdom] Correspondence of x-ray spectrum and atomic number discovered
by Henry Gwgn Jeffreys Moseley. Died 1915 in battle in Turkey. |
| 1914 |
[United Kingdom] H.G. Wells published "The World Set Free", in which he wrote about the creation of atomic weapons, their use and impact on the political world. The novel is significant due to its political and technical accuracy. It is one of the first written predictions of atomic weapons.
|
| 1914.6.28 |
The First World War triggered by assassination of Austrian Crown Prince
by a Serbian youth in Sarajevo. |
| 1915.11.25 |
[Germany] General theory of relativity presented by Albert Einstein, explaining
shift of orbit of the Mercury and predicting the refraction of star light
by mass of the sun. |
| 1917.5.25 |
[Germany] Bombing of Forkston, the first strategic bombing. |
| 1917 |
[United Kingdom] Emergence of isotope of oxygen atom and hydrogen nucleus by alpha-ray
irradiation of nitrogen atom, by E.Rutherford. |
| 1917.11.7 |
[Russia] October Revolution. |
| 1918 |
[United Kingdom] Mass spectroscopy developed by Francis William Aston, making it
possible to detect all isotopes. (Received 1922 Nobel prize.) |
| 1918.10 |
[Hungary] Revolution. |
| 1919.5.29 |
[United Kingdom] Detection of refraction of light of stars due to mass of the sun
by Arthur Stanley Eddington at a total eclipse of the sun in west Africa. |
| 1920 |
[United Kingdom] Proton proposed by E.Rutherford. |
| 1920.6.3 |
[United Kingdom] Isotope of hydrogen and neutron, a possible intrusion of neutron
into nucleus, proposed by E.Rutherford. |
| 1922.12 |
[Denmark] Hafnium, the 72nd element, discovered by Georgede Hevesy and D.Coster.
(CHAFNIA is Copenhagen in ancient Romanian regime.)Its existence was predicted
from the periodic table. |
| 1923 |
[U.S.A.] Compton effect, or Compton scattering, discovered by Arthur Compton.
Longer wave length of X-ray scattered by graphite, detected by a spectrometer.
A proof of particle nature of light. (Received 1927Nobel prize.) |
| 1923.11.8 |
[Germany] Adolf Hitler is sent to Landesberg prison for treason. There,
he dictates his autobiography Mein Kampf. |
| 1924 |
[France] Wave nature of electron proposed by Louis de Broglie.(Received
1929 Nobel prize.) |
| 1925 |
[Germany] Theory of quantum mechanics founded by Werner Karl Heizenberg
at the N.Bohr Institute, in Copenhagen, Denmark. (Received 1932Nobel prize.) |
| 1926 |
[Austria] Theory of wave mechanics developed by Erwin Schroedinger.(Received
1933 Nobel prize.) |
| 1927. 2 |
[Germany] Uncertainty principle proposed by E. Heisenberg. The idea that
light is not only wave but also particle emerged during a walk in a park
under a starlit sky . |
| 1927 |
[United Kingdom, U.S.A.] Wave nature of electron;Confirmation by George Paget Thomson
and Clinton Joseph Davisson. (Received 1937 Nobel prize.) |
| 1928 |
[U.S.A.]Positron; Prediction by Paul Adrian Maurice Dirac. Incorporation
of relativity to Schroedinger equation (spin of electron). (Received 1933Nobel
prize.) |
| 1929. 4 |
[U.S.A.] Idea of Cyclotron for accelerating sub-atomic particles occurred
to Ernest Orlando Lawrence and M.S.Livingston. |