Atomic Bomb Timeline
This timeline is being assembled collaboratively by the students in
Making the Bomb, a course being taught at the College of the
Atlantic, spring term, 1999.
This page is a work in progress
- 1704 Isaac Newton: modeled the atom using billiard balls.
- 1789 Martin Heinrich Klaproth extracted a grayish metallic
material from a sample of Joachimsthal pitchblend and named it Uranium.
- 1873 James Clerk Maxwell: introduced the electro magnetic
field around atoms.
- 1885 Balmer: the Balmer series was introduced, light was
shot through hydrogen and the light spectrum that came from it was
- 1887 Heinrich Hertz: discovered electric waves (radio).
- 1890 Rydberg: found a more consistent bomber series, led to
- 1895 William Roentgen: discovered x-rays.
- 1896 Henry Becquerel: finds radioactivity.
- 1897 J.J. Thompson: discovered electrons using cathode
rays, showed that glowing matter wasn't light waves.
- 1899 E. Rutherford: publishes discoveries on radiation,
including alpha and beta particles.
- Planck's quantized radiation formula. Plank discovers that
certain particles can only vibrate at certain energies, this led to
- (Through 1903): Rutherford and Soddy work on spontaneous decay
and radioactivity, half lives and the amount of energy released.
- Otto Hahn: went to work with Rutherford and helped him discover
that alpha rays were charged hydrogen atoms.
- Einstein shows that light sometimes behaves as if it consists not
of waves but of particles.
- Otto Hahn moved from Montreal to Berlin to work with Emil Fischer
(and organic chemist), leaving Ernest Rutherford behind.
- Adolf von Harnack was the first president of Kaiser Wilhelm Society.
- Bohr: suggest that the atom is stationary.
- Bohr discovers that radioactive particles come form the nucleus,
also elements are given exact place on the periodic table.
- May 25: Germans bomb (with planes) a civilian town. "Strategic
- October 23: Kaiser Wilhelm II dedicates first two Kaiser Wilhelm
institute: one for chemistry, one for physics, in Dahlem, southwest
- Bohr found a correlation between orbiting electrons and spectral
- May: Mosley and C.G. Darwin start using crystals and
spectroscopes and discover that they work very well. Mosley's results
eventually backed up Bohr's quantized electron orbits.
- August: Weismann discovers BY, and anaerobic organism that
decomposes starch while trying to develop a process for making
synthetic rubber. Because a side product was acetone (used for making
artillery propellant) the military became interested.
- April 22: Battle of Ypres. Germans use Chlorine gas.
- May 25: In the town of Folkestone on the Southeastern coast of
England, German Gotha bombers (biplanes) strategically bomb england
for the first time. Began first effective and sustained campaign of
strategic civilian bombardment.
- June 13: German squadron flew against London and caused the most
numerous civilian casualties of the war.
- July: Germany introduces mustard gas into WWI.
- Ernest Rutherford moved to Cavendish to take over for
- Oppenheimer tried to work with Rutherford, but was turned down.
- October: Hungarian Revolution, calls for Hungarian independence.
- March 21: republic of Hungary turns into Hungarian Soviet
- Fall: White terror of the Horthy regime begins in Hungary.
Anti-Semitism drives many Jews into exile.
- James Chadwick was Rutherford's assistant director of research.
- J.J. Thompson still worked at Cavendish and let Oppenheimer in to
work with him.
- January 18: Bohr opens his Institute for theoretical Physics in
- Bohr predicts that when element 72 is found it will be similar to
Zirconium. This linked chemistry to physics.
- Bohr wins the Nobel prize and become a Danish national hero.
- December: George deHevesy and Dirk Coster discovered element 72 which was
chemically almost identical to Zirconium.
- Early summer: Arnold Sommerfeld brought Werner Heisenberg with him
to hear Bohr lecture in Gottingen.
- Summer: Oppenheimer first encountered area of Los Alamos.
- Easter: Heisenberg went to Copenhagen and hiked with Bohr.
- May: Heisenberg goes to Heligoland for two weeks and develops
- June: Heisenberg, Max Born, and Pascal Jordan refine quantum
- Ed Teller left Hungary at age 17 to go to the Technical Institute
- Erwin Schroedinger shows that matter at the atomic level behaves as
if it consists of waves.
- Bohr and Schroedinger attempt to reconcile dualism of atom.
- Oppenheimer moved to Gottingen
- Wigner, Heisenberg, Pauli, Fermi, Franck, all present in Gottingen
along with Courant, Weyl, von Neumann, and Teller.
- Benito Mussolini's government convenes international physics
congress at Como, Italy.
- February: Bohr goes to Norway to ski. Heisenberg continued to
work attempting to calculate the trajectory of electron in cloud
chamber, realized it was hopeless.
- February: Heisenberg concludes "that on the extremely small scale
of the atom, there must be inherent limits to how precisely events
could be known." This is the uncertainty principle.
- September: At Como, Bohr proposes that particles and waves are
merely words and can be accepted side by side to describe the atom.
- September: Einstein refused to attend Como and support fascism.
- October: Solvay conference in Brussels attended by Einstein,
Bohr, Planck, Marie Curie, Lorentz, Born, Ehrenfest, Schroedinger,
- October: At Solvay conference Einstein refused to accept that
determinism at atomic level was impossible, claiming that "God does
not throw dice.
- October: Bohr disagrees with Einstein. Bohr responds, "Nor is it
our business to prescribe to God how He should run the world."
- Oppenheimer published 16 papers between 1926 and 1929.
- Oppenheimer accepts join positions at Caltech and Berkeley.
- Irene Curie succeeds her famous, but sadly mortally ill, mother
Marie as director of the Radium Institute in Paris.
- August 2: Carl Anderson, working with a carefully prepared cloud
chamber at the California Institute of Technology, discovers a
positively charged electron, the "positron." This was the first
indication that the universe consists not only of matter but of
antimatter as well.
- Fermi, Segre, Corbino, Amaldi, et al. open a well funded, richly
staffed physics research center in Rome, complete with a "well-made"
cloud chamber and a nearby radium source (as well as wooden and marble
tables), to begin intensive study of the atomic nucleus.
- October: Solvay Conference in Brussels, Belgium. For the first
time, this prestigious congregation was devoted purely to the
consideration of nuclear physics. Attendance at this affair was the
excuse the Soviet physicist George Gamow used to affect his
- Fermi and his "Boys" test artificial transmutation in a vast array
of elements. Observing the behavior of bombarded Uranium, they note
that one of its decay products is an unknown substance with a 13
minute half life. In the their following publication they suggest the
"possibility that the atomic number of the element may be greater than
- January 15: Irene Curie and her husband Frederic Joliot publish a
report in the Comptes Rendus describing that in the course of
experimentation with alpha particles to find the elusive neutron, they
discover how to make matter radioactive by artificial means. "These
experiments," they write, "give the first chemical proof of artificial
transmutation" (they win the Nobel Prize in Chemistry for the work the
- March 12: Leo Szilard, in London, files the first of several
patent applications relating to nuclear energy. By the end of the
1935, the lot of them would be merged into one complete specification:
"Improvements in or Relating to the Transmutation of Chemical
Elements." Without a bit of laboratory experimentation, Szilard was
already acting on his idea of nuclear chain reaction, with
applications from power production to, with a correct "critical mass"
of chain-reacting substance, "explosion."
- July 4: Marie Sklodowska Curie dies.
- September: Ida Noddack publishes "On element 93," in it proposing
"when heavy nuclei are bombarded by neutrons, it is conceivable that
the nucleus breaks into several large fragments, which would of course
be isotopes of known elements but would not be neighbors." This
highly insightful piece of work would largely go ignored.
- Noticing a disparity in results of the same experiment on tables
of wood and tables of marble, Amaldi and the Boys find that slowing
neutrons gives nuclei more time to effect their "capture;" Segre
would subsequently the highly effective neutron-slowing powers of
- Szilard begins searching for funds for his chain reaction
- Szilard requests for the British War Office to hold and keep
secret his patents for nuclear chain reactions. Not until February
1936, and with the prodding of Frederick Lindemann, does the Admiralty
accept the patent for safe-keeping.
- Civil war begins in Spain.
- January 27: Bohr, arguing for radical theoretical change,
introduces a model for a multi-particle atomic nucleus closely packed
and bound by the short range strong force. The following year, he
publishes another proposal explaining the usefulness of mathematically
modeling the nucleus as one would a drop of liquid.
- October 20: Ernest Rutherford dies.
- March: Hitler invades Austria
- May: Hitler visits Mussolini in Rome
- July 14: Manifesto della Razza -- "Jews do not belong to the
-- Italian race."
- Summer: Maurice Goldhaber emigrates to U.S.
- August: Bohr speaks at International Congress of Anthropologic
and Ethnographic Sciences in Helsingor, Zealand.
- September 1: Anti-Semitic laws passed in Italy
- Late January: Szilard asks Fermi to keep the possibility of
producting a chain reaction secret.
- February 5: Bohr draws 3 graphs that explain fission for Thorium,
U238, and U235, showing that any neutron (fast or slow) will fission U235.
- February 7: Bohr sends a paper on this off to The Physical Review.
- Late February: Joliot beging to identify secondary neutrons from
- Early March: Szilard gets radium to conduct his own experiments
to see if neutrons are emitted in the fission process, and he finds
that they are.
- March 14: Hitler orders the Foreign Minister of Czechoslovakia to
Berlin and threatens to bomb Prague unless the Czechs surrender to
- March 16: Czechoslovakia becomes a German protectorate
- March 16: Wigner, Szilard, Fermi and Pegram meet and Wigner says
that they should talk to the U.S. government about their discoveries
- March 17: Fermi meets twith Admiral Stanford C. Hooper from the
U.S. Navy to tell him about the possibility of the liberation of
atomic energy leading to powerful explosives that could have military
- March 17: Fermi, Teller, and Szilard discussed whether or not to
keep Physical Review papers secret. The decide not to publish.
- March 18: Joliot, VonHalban, and Kowarski published paper on
secondary neutron in Water.
- April 22: Joliot, VonHalban, and Kowarski publish second paper
in Nature on secondary neutron; Uranium would most probably
- April 29: Secret conference in Berlin leading to research
program, ban on Uranium exports, provisions for supplies of radium.
- April 29: Public debate in in Washington on Physics.
- June: Columbia team sends paper "Neutron production and
absorption in Uranium" to Physical Review.
- July 16: Wigner and Szilard meet with Einstein to discussion
- July: Szilard meets Alexander Sachs and discusses having Sachs
approach FRD about fission.
- July 30: Teller and Szilard visit Einstein for letter to FDR.
- September 1: Germany invades Poland at 4:45 am. WWII starts.
- September 3: Britain and France enter WWII.
- Fermi and Anderson set up a new project involving measuring
neutron production in a tank of liquid. Working with Szilard, they
found neutron activity about 10% higher with Uranium oxide than
- Fermi and Anderson leave to pursue other things
- Szilard comes up with the idea to use graphite as a moderator,
rather than water.
- Through correspondence with Fermi, the idea of using graphite
becomes steadily more plausible.
- After the success of the graphite experiment, Szilard, with help
from Einstein, wrote up a letter to the government about the
possibilities of fission (and also about the dangers of it).
- September 16: Conference in Berlin. Physicists learn that
German intelligence had discovered the beginning of Uranium research.
- September 29: Premier Eduardo Daladier, Mussolini, Hitler, and
Chamberlain met in Munich and decide to evacuate Sudentenland.
- October 21. Briggs, Sachs, Szilard, Wigner, Teller, Roberts,
Adamson, and Hoover meet to discuss war and physics. Chain reaction
experiments get funding.
- November 7: 17 year old Polish Jewish student attempts the
assassination of Ernst Vom Rath, the third secretary of the German
embassy in Paris.
- November 9: Vom Rath dies leading to Anti-Semitic riot leaving at
least 100 people dead. Work begins in USSR toward making an atomic
- 1941: Abelson's thermal diffusion column is developed as a cheap
way to make uranium hexaflouride
- April 19: Glen Seaborg arrives in Chicago
- August 20: Seaborg isolates Plutonium
- September 17: Leslie Richard Groves take over Manhattan Project
- October 15: Oppenheimer becomes director of Manhattan Project
- December 20: Fermi, Szilard finish pile CP-1
- Winter: Heavy water factory Vermark first attempted sabotage against.
- January: Abelson's report is released it states that uranium can
be enriched with in a single thermal diffusion column.
- February 2: Germans surrender at Stalingrad.
- March 15: Scientist move to Los Alamos
- May 27: Work began at Los Alamos-Fire bombing of Hamburg
- Summer: Batches of plutonium nitrate began arriving at Los Almos
- June 14: Oppenheimer met with Communist ex-love Jean Tatlock.
- August 13: First drops of prototype atom bomb 14/23 scale model.
- Sept. 17: First shots fired from an uranium gun.
- November: Pilot scale reactor at Oak Ridge goes critical.
- November: Abelson id authorized by the Navy to build his 300 column
- Winter: Bohr came to United States.
- December: Frisch comes to America and becomes a British citizen
- Teller and Bohr go to Los Alamos.
- December 24: the first radio station broadcast to the Hill.
- January: Jean Tatlock committs suicide.
- January: Kistiakowsky comes to Los Alamos
- February: Installation of B Pile.
February: Sinking of the Hydro.
- March: Planning began for full scale test of implosion bomb.
Oppenheimer code named it Trinity.
- May 1: Oppenheimer seeks to replace Teller with Peirls
- June 6: D-Day
- August 1: Tinian secured by America, Mass suicide on Saipan.
- September 26: The largeset atomic pile assembled. The first
plutonium production reactor is operating.
- December 7: Oppenheimer has second child.
[Making the Bomb]
[College of the Atlantic]