Chronology of Physics
Collection of major events in the history of
physics
The major source was
Issac Asimov's Biographical Encyclopedia of
Science and Technology.
2980 BCE
Imhotep lives in Egypt, designs step pyramid
at Sahara. Many other achievements
attributed to him.
1650 BCE
Ahmose, Egyptian scribe, writes Directions
for Attaining Knowledge of All Dark Things, a
text which deals with the solutions of many
simple equations such as finding volumes
and areas.
600 BCE
Anaximander introduces sundial to Greece,
is first person to attempt to draw map of
world, believes world is made of apeiron, a
word meaning infinite.
Thales predicts an eclipse of the moon,
generalizes Egyptian geometry, invents
deductive mathematics, studies magnetism
and states that fundamental material of
universe is water.
535 BCE
Anaximenes believes air the fundamental
element.
520 BCE
Xenophanes believes earth is the
fundamental element and that the mountains
were originally covered by the seas.
500 BCE
Pythagoras flourishes in Greece and
southern Italy. Founds mystery cult unique in
its emphasis on mathematics, including
belief that the whole universe rested on
numbers.
Heraclitus says the only permanent thing is
change, hence fire is the fundamental
element.
Hanno, a Carthaginian, is perhaps the first
person to sail around Africa.
450 BCE
Anaxagoras believes earth and stars created
of identical materials.
420 BCE
Democritus develops first atomic theory.
400 BCE
Zeno states that the senses are useless as a
means of obtaining knowledge and presents
a series of paradoxes, all based on fallacies,
to prove it.
Hippocrates stresses rationalism, careful
observation and honorable standards in the
practice of medicine.
350 BCE
Aristotle does much work in many sciences,
is most successful in biology. He argues for
a spherical Earth using lunar eclipses and
other observations. Many of his ideas about
physics remain in fashion for almost two
thousand years.
300 BCE
Aristarchus attempts to measure distances
from earth to moon and to sun, but large
experimental error causes him to be wrong
by factor of twenty.
Euclid writes The Elements, still the standard
in geometry
250 BCE
Archimedes, the greatest scientist of ancient
times, develops principles of density,
buoyancy, simple machines and computes pi
to two decimal places using inscribed and
cirumscribed polygons and the area under a
parabolic segment.
240 BCE
Eratosthenes, librarian at Alexandria,
determines that the Earth is a sphere with a
circumference of about 25,000 miles.
200 BCE
Apollonius writes On Conic Sections and
names the ellipse, parabola, and hyperbola.
150 BCE
Hipparchus invents the astrolabe and uses
parallax to determine that the distance to the
Moon is roughly 380,000 km.
134 BCE
Hipparchus creates the magnitude scale of
stellar apparent luminosities, discovers the
precession of the equinoxes and makes a
detailed star map.
50 AD
Hero, Greek engineer, builds first steam
engine and many other devices.
150
Ptolemy places earth at center of universe
with planets and sun moving around it.
Publishes Megale mathematike syntaxis,
generally known as the Almagest, a star
catalog.
450
Ch'ung-Chih and Keng-Chih compute pi to
six decimal places.
750
Geber, at height of Arab empire, adds sulfur
and mercury to the list of elements.
830
Al-khwarizmi introduces zero to west.
1202
Fibonacci explains use of Arabic numerals.
1249
Bacon writes about convex lens eyeglasses
for treating farsightedness
1260
Bacon calculates distance to stars as
130,000,000 miles.
1295
Polo returns to Venice after 20 years in
China.
1340
William of Ockham has a close shave with
the Pope, states that "Entities must not
needlessly be multiplied" [that is, the
simplest theory explaining facts is the correct
one.]
1424
al-Kashi computes pi to sixteen decimal
places using inscribed and circumscribed
polygons.
1452
da Vinci born; makes many contributions to
science and art during his life.
1454
Gutenberg begins publication of the Bible,
the first typeset book.
1480
da Vinci describes a workable parachute.
Behaim introduces the nautical astrolabe
1492
Columbus discovers the New World.
da Vinci describes a flying machine.
1520
Ferro develops a method for solving cubic
equations.
1521
Magellan observes the Magellanic Clouds
during his circumnavigating expedition.
1543
Copernicus publishes theory of heliocentric
solar system.
1569
Mercator issues the first Mercator projection
map
1572
Brahe observes nova, publishes De Nova
Stella.
1577
Brahe observes comet, parallax studies
show it is outside of atmosphere.
1581
Galileo discovers period of pendulum
independent of amplitude.
1589
Galileo uses balls rolling on inclined planes
to show that different weights fall with the
same acceleration.
1590
Janssen invents the microscope.
1593
Galileo invents thermoscope, a crude
thermometer but best until 1680's.
1596
van Ceulen computes pi to twenty decimal
places using inscribed and cirumscribed
polygons.
1598
Philip II of Spain announces prize for
invention of accurate ship chronometer
which would aid in navigation.
1600
Gilbert publishes De Magnete, shows
magnet dips towards pole.
1609
Galileo uses telescope to discover
mountains on moon, sunspots, satellites of
Jupiter, phases of Venus and many new
stars.
Kepler publishes Astronomia Nova, states
that planets move in ellipses [Kepler's first
law] and that a line connecting a planet to
the sun will sweep out equal areas in equal
times [Kepler's second law].
1610
Galileo sees Saturn's rings but does not
recognize that they are rings.
Kepler uses the dark night sky to argue for a
finite universe.
1611
Kepler discovers total internal reflection, a
small angle refraction law, and thin lens
optics
1613
Galileo uses sunspot observations to
demonstrate the rotation of the Sun
Napier publishes first table of logarithms.
1619
Kepler publishes his third law [square of
period of revolution proportional to cube of
distance].
1620
Bacon publishes Novum Organum, argues
that laws of science must be induced from
experiment.
1621
Snell discovers that light moving from rarer
to denser medium is bent towards vertical
[Snell's Law].
1622
Oughtred invents the slide rule.
1632
Galileo publishes Dialogue on the Two Chief
World Systems, argues in favor of
Copernican system.
1633
Galileo tried for heresy, renounces
Copernician system, Dialogue banned by
Church.
1635
Gellibrand publishes finding that compass
needle drifts with time.
1637
Descartes publishes Discourse on Method,
states mechanistic view of universe,
introduces use of coordinate system.
1640
Bullialdus suggests an inverse-square
gravitational force law.
1641
Gascoigne invents telescope cross hairs
1642
Galileo dies on January 8th.
Newton born on Dec 25th.
1643
Torricelli produces vacuum in closed cylinder
partially filled with mercury, produces first
barometer and shows air has "weight."
1646
Pascal confirms Torricellian view,
demonstrates pressure of atmosphere
decreases with altitude.
1650
Guericke constructs first air pump.
Riccioli discovers first double star.
1654
Guericke demonstrates the "power of the
vacuum" with use of Magdeburg spheres.
Pascal and Fermat create the theory of
probability.
1655
Cassini discovers Jupiter's great red spot.
1656
Huygens builds the first accurate pendulum
clock and identifies Saturn's rings as rings
and discovers Titan and the Orion Nebula.
1657
Fermat introduces the principle of least time
into optics
1662
Boyle discovers that volume of gas
decreases linearly with pressure.
1663
Royal Society founded.
1665
Newton discovers sunlight can be broken
into spectrum by prism.
Grimaldi's work on diffraction of light
publishes posthumously.
Cassini determines the rotational speeds of
Jupiter, Mars, and Venus.
1666
Newton determines that force varying as
1/r^2 would cause planets to move in
ellipses.
1668
Newton invents reflecting telescope.
Wallis suggests the law of conservation of
momentum.
1669
Newton appointed Lucasian Professor of
Mathematics at Cambridge.
Bartholin discovers double refraction.
1672
Guericke reports production of static electric
sparks made by rubbing rotating sulfur ball
with hand.
Montanari notices that Algol's brightness
varies.
1675
Romer uses the orbital mechanics of
Jupiter's moons to estimate that the speed of
light is about 227,000 km/s.
1676
Mariotte independently discovers Boyle's
Law [P-V behavior of gases].
1678
Hooke discovers that restoring force of
spring proportional to displacement from
equilibrium position [Hooke's Law].
Huygens states his principle of wavefront
sources.
1687
Newton publishes Philosophiae Naturalis
Principia Mathematica, containing the
principle of inertia [Newton's First Law], the
definition of of force [Newton's Second Law]
and the statement that every action has an
equal and opposite reaction [Newton's Third
Law].
1690
Huygens argues that light is a longitudinal
wave.
1693
Leibniz states law of the conservation of
mechanical energy.
1699
Amontons publishes work on P-T behavior of
gases.
1700
Savery invents "The Miner's Friend", first
working steam engine.
1701
Halley suggests using the salinity and
evaporation of the Mediterranean to
determine the age of the Earth.
1704
Newton publishes Opticks.
1705
Halley demonstrates the periodicity of certain
comets, predicts one will return in 1758.
1706
Machin develops a quickly converging
inverse-tangent series for pi and computes pi
to 100 decimal places.
1707
Lack of accurate chronometers causes
British fleet to miscalculate its position and
crash on rocks off Cornwall.
1712
Newcomen invents improved steam engine.
Taylor develops Taylor series.
1713
British government announces prize for
construction of accurate ships' chronometer
which would aid in navigation.
1714
Fahrenheit invents mercury thermometer.
1716
Halley suggests a high precision
measurement of the Sun-Earth distance by
timing the transit of Venus.
1728
Harrison constructs accurate chronometer,
claims prize announced in 1707.
1729
Newton's Principia Mathematica published in
English.
Gray discovers principle of electrical
conduction.
1731
Reaumur invents water - alcohol
thermometer.
1733
Du Fay studies electrical repulsion,
postulates "vitreous electricity" and "resinous
electricity", each of which repels itself but is
attracted to the other. [demo E1,2,3]
Bradley measures diameter of Jupiter.
1737
Voltaire has one of his mistresses translate
Newton's Principia into French and writes an
appropriate introduction.
1738
Bernoulli publishes book on fluid flow, shows
that as velocity of fluid increases, its
pressure decreases [Bernoulli's Principle].
1742
Celsius proposes temperature scale based
on one hundred degrees between freezing
and boiling points of water.
1745
Leyden Jar invented at University of Leiden.
[demo]
Lomonosov proposes law of conservation of
mass [year approximate].
1747
Franklin invents lightning rod.
Lind discovers that citrus fruits prevent
scurvy.
1752
Franklin flies kite during thunderstorm,
demonstrates that lightning is a form of
electricity.
1756
Canton notices effect of aurora borealis on
compass needle.
1758
Dollond produces achromatic lens.
1759
Halley's comet, due to gravitational effects of
Saturn and Jupiter, returns a year later than
predicted.
1765
Harrison finally awarded prize for design of
chronometer.
1766
Cavendish announces discovery of
hydrogen.
1768
Cook observes transit of Venus from island
of Tahiti.
1769
Watt invents improved steam engine.
1771
Galvani notices that muscles of dissected
frogs twitch when touched by electric spark.
Messier publishes first list of nebulae.
Priestly discovers that plants convert carbon
dioxide into oxygen.
1780
Lagrange and Laplace show the heat
evolved in the formation of a compound from
its elements equals the amount required to
decompose compound into its elements.
1781
Herschel discovers the planet Uranus
1782
Goodricke notices that the brightness
variations of Algol are periodic and proposes
that it is partially eclipsed by a body moving
around it.
1783
Watt defines the horsepower as 550 footpounds per second.
Montgolfier brothers launch first balloon, it
goes 1500 feet upward and a mile and a half
downwind in 10 minutes.
Charles constructs first hydrogen filled
balloon.
1784
Blanchard sails hydrogen balloon across
English Channel.
1785
Coulomb shows that electrical force varies
as 1/r^2. [demo]
1786
Chladni uncovers quantitative relationships
governing transmission of sound.
Galvani discovers `animal electricity' and
postulates that animal bodies are
storehouses of electricity.
1787
Lavoisier publishes Methods of Chemical
Nomenclature.
Charles rediscovers P-T behavior of gases
but fails to publish.
1788
Lagrange publishes Analytical Mechanics,
uses calculus of variations to solve
generalized problems in mechanics.
1789
Lavoisier publishes Elementary Treatise on
Chemistry, first modern chemistry textbook.
1790
Fitch launches first practical steamship.
1791
Prevost shows that cold does not flow from
cool objects to hot ones.
1791
Faraday born.
1792
Murdock discovers coal gas.
1793
Herschel discovers double stars circle one
another.
Lagrange, Laplace, Lavoisier and others
appointed by rulers of French Revolution to
committee for the development of new
system of weights and measures.
Whitney invents cotton gin.
1794
Lavoisier is guillotined during the French
Revolution.
1795
Lagrange, Laplace and other survivors
announce the metric system.
Gauss invents the method of least squares
while still a teenager.
1797
Garnerin demonstrates first use of a
parachute.
1798
Cavendish measures value of G, the
gravitational constant.
Rumford shows that mechanical energy can
be converted into heat.
Whitney devises assembly line production of
rifles.
1799
Laplace begins publication of Celestial
Mechanics [finished in 1825].
************************** 1800
*************************************
Volta invents the electric battery.
Herschel discovers infrared light.
Davy discovers nitrous oxide [laughing gas].
1801
Young announces cause of astigmatism.
Ritter discovers ultraviolet light.
Piazzi discovers the asteroid Ceres.
Jacquard invents the Jacquard punched card
loom.
Fulton builds the first submarine.
1802
Gay-Lussac rediscovers P-T behavior of
gases and publishes.
Wollaston finds seven dark lines in solar
spectrum.
1803
Dalton first proposes modern atomic theory.
Young discovers diffraction of light by slits;
proposes light is a wave.
Biot announces that stony material falling
from skies are meteorites.
1804
Rumford marries widow of Lavoisier. They
are divorced four years later. Rumford
remarks that Lavoisier was lucky to have
been guillotined.
Biot shows that earth's magnetism
undiminished by altitude but panics during
balloon flight.
1806
Argand associates vectors with complex
numbers and studies complex number
operations in geometrical term.
1807
Fulton launches the first profitable
steamship.
Fourier announces that any periodic
oscillation can be broken into a series of
simpler regular oscillations.
Davy uses electric current to isolate
potassium.
1808
Dalton publishes New System of Chemical
Philosophy.
1809
Lamarck proposes an inheritance of
acquired characteristics theory of evolution.
1811
Avogadro proposes that at same
temperature, equal volumes of gases contain
equal number of particles.
1814
Fraunhofer discovers hundreds of dark lines
in solar spectrum.
Stephenson builds the first practical steam
powered railroad locomotive.
1815
Biot shows that solutions of organic
materials rotate polarized light.
Brewster shows reflection polarizes light.
1816
Brewster invents kaleidoscope.
1817
Young states that light is a transverse wave.
Pelletier and Caventou isolate chlorophyll.
1818
Dulong and Petit find atomic weight and
specific heat inversely related.
1820
Oersted discovers electric current affects
compass needle. [demo]
Ampere, one week later, announces right
hand screw rule.
1821
Seebeck discovers thermoelectricity.
Faraday builds an electricity-powered motor.
1822
Niepce produces first photograph.
Fourier states that a scientific equation must
involve a consistent set of units.
Mantell discovers the fossilized skeleton of
an iguanodon dinosaur.
1823
Ampere postulates tiny electrical currents in
iron as source of magnetism.
Faraday liquefies carbon dioxide, chlorine
and other gases.
1824
Carnot publishes On the Motive Power of
Fire, which defines potential energy and
demonstrates the maximum efficiency of an
engine depends on the temperature
difference between the hottest and coldest
parts.
1825
Stephenson produces first practical steam
locomotive.
Faraday discovers benzene.
1826
Niepce takes the first permanent
photograph.
1827
Ohm discovers current directly proportional
to voltage, inversely proportional to
resistance.
Babinet proposes unit of length be based on
a specified wavelength of light.
1828
Nicol produces polarized light by use of
double refraction.
Berzelius publishes uses modern chemical
notation in table of atomic weights.
Sturgeon produces practical electromagnet.
Wohler discovers ammonium cyanate can be
converted into urea.
1830
Henry, during summer vacation, begins work
on magnetic induction. Not quite finished, he
plans to complete it the next summer.
1831
Maxwell born.
Henry invents an electric telegraph,
describes electric motor.
Schwabe discovers Jupiter's great red spot.
Faraday finds that changing magnetic field
produces electric current and announces the
discovery of magnetic induction. [demo]
Graham finds rate of diffusion of gas
inversely proportional to square root of molar
weight.
1832
Gauss devises logical system of units of
magnetism.
Faraday codifies laws of electrolysis.
Henry discovers self-induction.
1833
Gauss invents an electric telegraph.
British Association for the Advancement of
Science founded.
Lenz finds resistance of metals changes with
temperature.
1834
Lenz generalizes law of magnetic induction.
Clapeyron presents a formulation of the
second law of thermodynamics.
1835
Galileo's Dialogue removed from Index of
Prohibited Books.
Henry invents electric relay.
Coriolis begins study of motion on a spinning
surface (see also)
Morse develops the Morse code.
1836
Daniell invents first reliable electric battery.
1837
Wheatstone invents an electric telegraph.
Agassiz begins his glaciation studies which
eventually demonstrate that the Earth has
had at least one Ice Age.
1838
Bessel uses parallax method to determine
distance from earth to a star - six light years
or 35,000,000,000,000 miles.
1839
Grove invents electric battery utilizing
hydrogen and oxygen.
Goodyear invents vulcanized rubber.
1840
Morse patents an electric telegraph using
Morse code.
1842
Doppler works out relationship relating pitch
to relative motion of source and observer.
Mayer presents evidence on the
conservation of energy.
1843
Schwabe announces that sunspots wax and
wane on eleven year cycle.
Joule experimentally finds the mechanical
equivalent of heat.
1844
Bessel discovers dark companion to Sirius.
1845
Rosse discovers spiral galaxies.
Stokes begins work on flow of viscous fluids.
Leverrier observes a 35'' per century excess
precession of Mercury's orbit.
1846
Weber introduces logical system of electrical
units.
Adam and Leverrier independently discover
Neptune.
Lassell, within a month, discovers Triton,
satellite of Neptune.
Kelvin, from physical principles, calculates
age of earth as somewhere between 20 and
400 million years.
1847
Boole publishes work The Calculus of Logic
on symbolic logic.
Joule publishes work on the conservation of
energy.
Helmholtz publishes work on the
conservation of energy. (for a different view,
check out this)
1848
Kelvin proposes that energy of gas is zero at
-273 Celsius.
1849
Fizeau and Foucault measure the speed of
light to be about 298,000 km/s.
1850
Clausius begins work on ratio of heat content
to temperature.
1851
Foucault uses pendulum to show that earth
rotates.
1852
Otis invents first safe elevator.
Joule and Thompson [Lord Kelvin] announce
cooling of gases by expansion.
Foucault invents the gyroscope.
1855
Geissler invents mercury vacuum pump.
Balmer devises formula to predict
wavelengths of light in hydrogen spectrum.
1856
Bessemer invents blast furnace.
Perkin invents the first synthetic dye.
1857
Maxwell shows that Saturn's rings must
consist of small particles.
1858
Darwin and Wallace announce theory of
evolution due to natural selection.
1859
Carrington discovers solar flares.
Darwin publishes On the Origin of Species
by Means of Natural Selection, or the
Preservation of Favored Races in the
Struggle for Life.
Nobel begins manufacture of nitroglycerin.
Plante invents rechargeable battery.
1860
Bunsen and Kirchoff invent optical
spectroscopy, discover two elements.
Swan invents primitive electric light bulb.
Maxwell begins work on statistical
thermodynamics.
1861
Graham discovers colloids.
1862
Lord Kelvin attempts to find the age of the
Earth by examining its cooling time and
estimates that the Earth is between 20--400
million years old.
1864
Maxwell begins work on electromagnetism,
finishes in 1873.
1865
Clausius introduces the term entropy.
Mendel publishes his work on genetics in a
local journal.
Pasteur announces germ theory of disease.
Kekule proposes ring structure for benzene.
1866
Field finances first trans-Atlantic cable.
Kundt studies the velocity of sound in gases.
Schiaparelli realizes that meteor showers
occur when the Earth passes through the
orbit of a comet that has left debris along its
path.
1868
Westinghouse patents the air brake.
Janssen discovers helium on sun.
1869
Mendeleev publishes his discovery of
chemical periodicity.
Miescher discovers nucleic acids in the
nuclei of cells.
1870
Meyer publishes his discovery of chemical
periodicity.
1871
Boltzmann begins work on statistical
mechanics.
1872
van de Waals publishes work on deviation of
real gases from ideal gas law.
1873
Maxwell discovers Maxwell
equations;
states that light is an
electromagnetic
phenomenon.
1874
van't Hoff and Le Bel advance a threedimensional stereochemical representation
of organic molecules and propose a
tetrahedral carbon atom.
Kelvin formally states the second law of
thermodynamics.
1875
Crookes invents radiometer.
1876
Gibbs begins publication of papers on free
energy and chemical potential in the
Transactions of the Connecticut Academy of
Sciences.
Bell patents the telephone.
Otto invents four-stroke internal combustion
engine.
1877
Cailetet liquefies oxygen and nitrogen.
Edison invents the phonograph.
1879
Stokes announces that radiation content of
body proportional to fourth power of its
absolute temperature.
Edison invents the practical light bulb.
Einstein born.
1880
Milne invents the seismograph.
1882
Stewart proposes existence of ionosphere.
Ferdinand Lindemann proves that pi is
transcendental and that the circle cannot be
squared with a compass and straightedge.
1883
Maxim invents the machine gun.
Amagat pressurizes gas to 3000
atmospheres.
1885
Stanley invents the alternating current
transformer.
1886
Goldstein demonstrates existence of positive
rays in cathode ray tubes.
Mach proposes that all matter is sensation.
1887
Michelson and Morley, using interferometry,
fail to detect earth's motion through ether.
Hertz detects electromagnetic
waves. [1 + 2 x demo]
1888
Hertz discovers the photoelectric effect.
1889
Edison invents practical motion picture
projector.
1891
Stoney proposes the name "electron" for
carrier of negative charge.
1893
Wien finds that blackbody radiation has a
peak at intermediate wavelengths but fails to
find theory to predict this.
Mach states Mach's principle---first
constructive attack on the idea of Newtonian
absolute space.
1894
Ramsay and Raleigh discover argon.
1895
Roentgen discovers x-rays emitted from
cathode ray tube.
Fitzgerald proposes objects shrink in the
direction of motion.
Ramsay discovers helium in rocks containing
uranium.
Curie [Pierre] discovers materials lose
magnetism at certain critical temperature.
1896
Nobel dies, wills fortune to establishment of
annual prize in Peace, Literature,
Physiology, Chemistry and Physics.
Becquerel discovers radioactivity.
Sperry invents gyroscopic compass.
1897
Braun invents the oscilloscope.
Thomson measures e/m of electron.
1898
Dewar liquefies hydrogen.
1899
Dewar solidifies hydrogen.
Rutherford discovers that uranium radiation
is composed of positively charged alpha
particles and negatively charged beta
particles.
******************************* 1900
**************************************
Freud publishes The Interpretation of
Dreams.
Planck proposes that light is emitted in
quanta, explains blackbody radiation.
Villard discovers radiation consists of two
types which are bent in different directions
by magnetic field.
Sabine uses acoustical principles to design
Boston Symphony Hall.
1901
Zeeman discovers that source of light in
intense magnetic fields produces several
split spectral lines.
Lebedev shows light exerts pressure.
Marconi sends radio signal from England to
Newfoundland.
1903
Crookes shows that alpha particles cause
zinc blende to luminesce.
Wright brothers fly at Kitty Hawk.
1904
Fleming invents the rectifier.
Barkla shows x-rays are electromagnetic.
1905
Nernst announces that it is impossible to
reach absolute zero [third law of
thermodynamics].
Einstein publishes three
papers - one on Brownian
motion confirms existence of
atoms, another on
photoelectric effect confirms
existence of photons, third
announces special relativity.
**** finał klasycznej, początek
kwantowej elektrodynamiki
****
1906
Fessenden demonstrates modulation of
radio waves.
De Forest invents the triode.
1907
Einstein introduces the principle of
equivalence of gravitation and inertia and
uses it to predict the gravitational redshift.
Fischer artificially synthesizes peptide amino
acid chains and thereby shows that amino
acids in proteins are connected by amino
group-acid group bonds.
1908
Kamerlingh-Onnes liquefies helium.
Haber discovers fixation of nitrogen which
allows Germany to make explosives.
Boltwood suggests that minerals can be
dated by determining Pb/U ratio.
Rutherford studies scattering of alpha
particles by gold.
1909
Peary and Henson reach the North Pole.
Rutherford states that alpha particle is
helium.
Einstein gets a professorship at University of
Zurich.
1911
Kamerlingh-Onnes discovers liquid helium is
a superconductor.
Millikan measures charge of electron. [demo]
Wilson invents cloud chamber.
Rutherford announces theory of nuclear
atom.
Amundsen reaches the South Pole.
Hess studies cosmic rays using balloons.
1912
Laue shows x-rays diffracted by crystals.
Bohr begins work on quantum theory of
atom.
1913
Perrin measures size of atoms via Einstein's
explanation of Brownian motion, finally
confirms Dalton's atomic theory.
Stark finds strong electric field splits spectral
lines.
Geiger invents counter for measuring
radiation.
Bohr presents his quantum model of the
atom.
1914
Rutherford suggests fundamental particle of
positive charge is the proton.
Moseley shows x-ray absorption edge of
element a function of its atomic number.
Ramanujan publishes Modular Equations
and Approximations to pi.
1915
Einstein announces theory of general
relativity.
Braggs [father and son] use x-rays to
determine crystal structures.
1916
Lewis introduces theory of chemical bonding.
1917
Jeans suggests planets formed when sun
encounters another star.
Einstein introduces the idea of stimulated
radiation emission.
1919
Ashton uses mass spectrograph to discover
isotopes.
Eddington leads a solar eclipse expedition
which claims to detect gravitational
deflection of light by the Sun.
1920
Michelson uses interferometry to measure
diameter of Betelgeuse.
1921
Capek, a Czech dramatist, introduces the
word 'robot' ("forced work") in his play R.U.R.
1922
Compton studies X-ray photon scattering by
electrons.
1923
Michelson uses interferometry to measure
speed of light, obtains a value of
299,798,000 m/s.
de Broglie associates wavelength of particles
with velocity.
1924
Eddington relates mass of star to its
luminosity.
Appleton discovers the ionosphere.
Bose and Einstein introduce Bose-Einstein
statistics.
1925
Millikan names radiation from outer space
"cosmic rays".
Pauli announces exclusion principle.
Uhlenbeck and Goudsmit postulate electron
spin.
Baird transmits the first television signal.
1926
Goddard launches his first rocket.
Schrodinger publishes wave
equation for H atom.
Dirac introduces Fermi-Dirac statistics.
Lang's Metropolis features an evil, but sexy,
robot.
1927
Davisson shows electrons exhibit diffraction.
Bohr states principle of complementarity
which says that a phenomenon can be
described as wave-like or particle like but not
both.
Heisenberg develops uncertainty principle.
Born interprets the probabilistic nature of
wavefunctions.
1928
Raman discovers light scattered by
molecules with shifted wavelengths.
Fleming discovers penicillin.
Horton and Morrison build the first quartz
crystal oscillator clock
1929
Hubble shows distance to galaxies related to
their velocities.
Bothe develops method of coincidence to
study cosmic rays.
Cockcroft and Walton design electrostatic
atom smasher.
Gamow proposes hydrogen fusion as the
energy source for stars.
1930
Oort calculates sun revolves around galactic
center once every 200,000,000 years.
Dirac postulates existence of positron.
Chandrasekhar discovers the white dwarf
maximum mass limit.
Tombaugh discovers Pluto.
1931
Urey discovers heavy hydrogen.
Pauli suggests existence of neutrino.
Van de Graaff develops electrostatic atom
smasher.
Godel shows even mathematics is uncertain.
1932
Chadwick discovers the neutron.
Anderson discovers the positron.
Heisenberg presents the proton-neutron
model of the nucleus and uses it to explain
isotopes.
1933
Rabi begins work on molecular beams
leading to studies of great accuracy.
Zwicky and Baade propose the neutron star
idea and suggest that supernovae might be
created by the collapse of normal stars to
neutron stars---they also point out that such
events can explain the cosmic ray
background.
1934
Joliot - Curies discover artificial radioactivity.
Cherenkov observes radiation in wake of
electron's passage.
1935
Dempster discovers U-235.
Blackett discovers gamma rays can produce
postitron - electron pairs.
Yukawa postulates that nuclear force is an
exchange of mesons.
Einstein, Podolsky, and Rosen put forth the
EPR paradox.
Richter invents a logarithmic scale to
measure the intensity of earthquakes.
1936
Wigner works out theory of neutron
absorption.
1937
Neddermeyer, Anderson, Street, and
Stevenson discover muons using cloud
chamber measurements of cosmic rays.
1938
Hahn and Strassman discover fission of
uranium.
Meitner and Frisch determine that nuclear
fission is taking place in the HahnStrassman-Meitner experiments.
Zworykin develops first practical TV camera.
Bethe works out nuclear mechanism of sun.
1939
Einstein writes letter to FDR stating that
nuclear weapons could be made.
Elsasser postulates earth's magnetic field
due to eddy currents in liquid core.
1940
MacMillan discovers neptunium.
1941
Seaborg isolates plutonium.
Flerov discovers spontaneous fission of
uranium.
1942
Enrico Fermi makes the first controlled
nuclear chain reaction.
Stuckelberg introduces the propagator to
positron theory and interprets positrons as
negative energy electrons moving
backwards through spacetime.
1943
Oppenheimer placed in charge of Manhattan
Project.
Schrodinger delivers the 'What Is Life?'
lectures at Trinity College, Dublin.
1944
Von Braun develops V-2 rocket.
1945
World enters nuclear age at Alamogordo on
July 16.
Hiroshima destroyed by nuclear weapon on
August 6.
1946
Bloch and Purcell develop nuclear magnetic
resonance.
Eckert and Mauchly announce ENIAC, the
first practical entirely electronic computer.
1947
Powell discovers pi meson.
Libby introduces carbon-14 dating.
First supersonic flight.
1948
Goeppert - Mayer shows nuclei consist of
protons and neutrons in shells.
Bardeen, Brattain and Shockley construct
the first transistor.
Casimir predicts a rudimentary attractive
Casimir force on a parallel plate capacitor.
Bondi, Gold, and Hoyle propose steady state
cosmologies based on the perfect
cosmological principle.
1949
von Neumann computes pi to 2,037 decimal
places using ENIAC.
1950
Oort suggests sun surrounded by vast cloud
of comets.
Turing proposes the `Turing test' criterion for
an intelligent machine.
1952
World enters thermonuclear age as first
fusion weapon explodes
Glaser constructs first bubble chamber.
Franklin uses X-ray diffraction to study the
structure of DNA and suggests that its sugarphosphate backbone is on its outside.
1953
Townes produces first maser.
Watson and Crick discover structure of DNA.
Ewing and Heezen discover the Great
Global Rift running along the Mid-Oceanic
Ridge.
Miller shows that amino acids can be formed
when simulated lightning is passed through
vessels containing water, methane,
ammonia, and hydrogen.
1954
Piccard designs bathyscaphe which reaches
depth of 2.5 miles.
Construction of the first nuclear power
reactor.
First FORTRAN compiler written.
1955
Bridgeman creates artificial diamonds from
carbon under pressure.
Segre and Chamberlain create anti-protons.
1956
Lee and Yang propose parity is violated in
beta decay.
Wu discovers parity violation by the weak
force in beta decaying cobalt-60.
1957
Russians launch Sputnik, first earth satellite.
Townes speculates on building a laser.
Bardeen, Cooper, and Schrieffer develop the
BCS theory of superconductivity.
1958
Van Allen discovers earth surrounded by
belts of radiation.
Mossbauer shows it is possible to produce
"recoilless" gamma rays.
1960
Gagarin first man to fly in space.
1961
Woodward synthesizes chlorophyll.
Gell-Mann and Ne'eman discover the
Eightfold Way patterns---SU(3) group.
Shanks and Wrench compute pi to 100,000
decimal places using an inverse-tangent
identity and an IBM-7090 computer.
1962
Lederman shows that the electron neutrino is
distinct from the muon neutrino.
Mariner 2 is the first mission to Venus.
1963
Vine and D.H. Matthews explain the stripes
of magnetized rocks with alternating
magnetic polarities running parallel to midocean ridges as due to sea floor spreading
and the periodic geomagnetic field reversals
Gell-Mann and Zweig propose the
quark/aces model.
1964
Fitch and Cronin show neutral kaon decay
violates CPT invariance.
Bell shows that all local hidden variable
theories must satisfy Bell's inequality.
1965
Weber puts the first Weber bar gravitational
wave detector into operation.
Mariner 4 sends the first clear pictures of
Mars.
1966
Luna 10 becomes the first spacecraft to orbit
the Moon.
1967
Gurdon uses nuclear transplantation to clone
a clawed frog---first cloning of a vertebrate.
1969
Armstrong first man to walk on moon.
Staelin, Reifenstein, Cocke, Disney, and
Taylor discover the Crab Nebula pulsar thus
connecting supernovae, neutron stars, and
pulsars
Snyder, Buhl, Zuckerman, and Palmer find
interstellar formaldehyde
1971
Texas Instruments releases the first easily
portable electronic calculator.
1972
Freedman and J.C. Clauser perform the first
polarization correlation test of Bell's
inequality.
1973
Fairchild Semiconductor releases the first
large image forming CCD chip---100 rows
and 100 columns.
Ostriker and Peebles discover that the
amount of visible matter in the disks of
typical spiral galaxies is not enough for
Newtonian gravitation to keep the disks from
flying apart or drastically changing shape.
1974
Richter and Ting discover the J/psi meson
implying the existence of the charm quark.
Mariner 10 passes by and photographs
Mercury.
1975
Perl discovers the tauon.
1976
Appel and Haken use a computer to solve
the four-color problem.
Viking I and Viking II land on Mars.
1977
Apple Computer releases the Apple II.
1978
Christy discovers Charon.
1979
Voyager 1 and Voyager 2 send back images
of Jupiter and its system.
1980
Guth proposes the inflationary Big Bang
universe as a possible solution to the horizon
and flatness problems
Alvarez, Alvarez, Asaro, and Michel propose
that a giant comet or asteroid may have
struck the Earth approximately 65 million
years ago thereby causing massive
extinctions and enriching the iridium in the KT layer.
1983
Rubbia, van der Meer, and the CERN UA-1
collaboration find the W and Z intermediate
vector bosons
1984
Jeffreys devises a DNA fingerprinting
method.
1985
Kroto, Heath, O'Brien, Curl, and Smalley
discover the unusual stability of the carbon60 Buckminsterfullerine molecule and
deduce its structure.
1986
Voyager spacecraft encounters Uranus.
Five spacecraft present at return of Halley's
Comet.
Universe discovered to have "bubble-like
structure."
Solar neutrino problem plagues physicists.
High temperature superconductors
discovered by Bednorz and Muller.
1987
Burstein, Davies, Dressler, Faber, LyndenBell, Terlevich, and Wegner claim that a
large group of galaxies within about 200
million light years of the Milky Way are
moving together towards `The Great
Attractor.'
Shelton discovers supernova 1987A in the
Large Magellanic Cloud.
Kanada, Bailey, Borwein, and Borwein use
iterative modular equation approximations to
elliptic integrals and a NEC SX-2
supercomputer to compute pi to 134 million
decimal places
1989
The Z intermediate vector boson resonance
width indicates three quark-lepton
generations.
Voyager 2 sends back images of Neptune
and its system
1990
Launch of the Hubble Space Telescope.
1992
COBE satellite detects unevenness in
cosmic background radiation arising from
'lumpy' structure at Big Bang.
Solar neutrinos detected by gallium
detectors; 1.6 atoms per day react in 1029
atom detector; new results still lower than
value predicted by standard solar model.
1994
Xia proves that a system of three bodies
moving under the influence of gravity is not
integrable and is chaotic.
1997
Sojourner, a six-wheeled robot rover the size
of a microwave oven, roams the surface of
Mars.
Wilmut announces he has cloned a sheep.
1998
Rather than slowing down, the Universe is
found to be expanding at an ever increasing
rate. This finding ties together numerous
elements into a consistent cosmic portrait.
A torrent of gamma rays from a magnetar, a
highly magnetized star, located 20,000
lightyears from Earth disrupts
communication satellites.
The shortfall of neutrinos passing through
the Earth presents strongest evidence yet of
neutrino mass.
Quantum teleportation is demonstrated when
a photon's polarization state is instantly
transferred to a remote photon.
The search for magnetic monopoles with
high particle masses comes up empty.