-260 Archimedes mathematically works out the
principle of the lever and discovers the principle of buoyancy
60 Hero of Alexandria writes
{\sevenit Metrica}, {\sevenit Mechanics}, and {\sevenit Pneumatics}
1490 Leonardo da Vinci describes capillary
action
1581 Galileo Galilei notices the timekeeping
property of the pendulum
1589 Galileo Galilei uses balls rolling on
inclined planes to show that different weights fall with the same acceleration
1638 Galileo Galilei publishes {\sevenit
Dialogues Concerning Two New Sciences}
1658 Christian Huygens experimentally discovers
that balls placed anywhere inside an inverted cycloid reach the lowest
point of the
cycloid in the same
time and thereby experimentally shows that the cycloid is the isochrone
1668 John Wallis suggests the law of conservation
of momentum
1687 Isaac Newton publishes his {\sevenit
Principia Mathematica}
1690 James Bernoulli shows that the cycloid
is the solution to the isochrone problem
1691 Johann Bernoulli shows that a chain
freely suspended from two points will form a catenary
1691 James Bernoulli shows that the catenary
curve has the lowest center of gravity that any chain hung from two fixed
points can have
1696 Johann Bernoulli shows that the cycloid
is the solution to the brachistochrone problem
1714 Brook Taylor derives the fundamental
frequency of a stretched vibrating string in terms of its tension and mass
per unit length
by solving an ordinary
differential equation
1733 Daniel Bernoulli derives the fundamental
frequency and harmonics of a hanging chain by solving an ordinary differential
equation
1734 Daniel Bernoulli solves the ordinary
differental equation for the vibrations of an elastic bar clamped at one
end
1738 Daniel Bernoulli examines fluid flow
in {\sevenit Hydrodynamica}
1739 Leonhard Euler solves the ordinary differential
equation for a forced harmonic oscillator and notices the resonance phenomenon
1742 Colin Maclaurin discovers his uniformly
rotating self-gravitating spheroids
1747 Pierre-Louis Moreau de Maupertuis applies
minimum principles to mechanics
1759 Leonhard Euler solves the partial differential
equation for the vibration of a rectangular drum
1764 Leonhard Euler examines the partial
differential equation for the vibration of a circular drum and finds one
of the Bessel
function solutions
1788 Joseph Lagrange presents Lagrange's
equations of motion in {\sevenit M\'ecanique Analytique}
1789 Antoine Lavoisier states the law of
conservation of mass
1821 William Hamilton begins his analysis
of Hamilton's characteristic function
1834 Carl Jacobi discovers his uniformly
rotating self-gravitating ellipsoids
1834 John Russell observes a nondecaying
solitary water wave in the Union Canal near Edinburgh and uses a water
tank to study the dependence
of solitary water
wave velocities on wave amplitude and water depth
1835 William Hamilton states Hamilton's canonical
equations of motion
1835 Gaspard de Coriolis examines motion
on a spinning surface deduces the Coriolis effect
1842 Christian Doppler examines the Doppler
shift of sound
1847 Hermann Helmholtz formally states the
law of conservation of energy
1851 Jean-Bernard Foucault shows the Earth's
rotation with a huge pendulum
1902 James Jeans finds the length scale required
for gravitational pertrubatations to grow in a static nearly homogeneous
medium
Electromagnetism and Classical Optics
130 Claudius Ptolemaeus tabulates angles
of refraction for several media
1269 P\`elerin de Maricourt describes magnetic
poles and remarks on the nonexistence of isolated magnetic poles
1305 Dietrich von Freiberg uses crystalline
spheres and flasks filled with water to study the reflection and refraction
in raindrops that
leads to primary
and secondary rainbows
1604 Johannes Kepler describes how the eye
focuses light
1611 Marko Dominis discusses the rainbow
in {\sevenit De Radiis Visus et Lucis}
1611 Johannes Kepler discovers total internal
reflection, a small angle refraction law, and thin lens optics
1621 Willebrord Snell states his law of refraction
1637 Ren\'e Descartes quantitatively derives
the angles at which primary and secondary rainbows are seen with respect
to the angle of the
Sun's elevation
1657 Pierre de Fermat introduces the principle
of least time into optics
1678 Christian Huygens states his principle
of wavefront sources
1704 Isaac Newton publishes {\sevenit Opticks}
1728 James Bradley discovers the aberration
of starlight and uses it to determine that the speed of light is about
283,000 km/s
1752 Benjamin Franklin shows that lightning
is electricity
1767 Joseph Priestly proposes an electrical
inverse-square law
1785 Charles Coulomb introduces the inverse-square
law of electrostatics
1786 Luigi Galvani discovers ``animal electricity''
and postulates that animal bodies are storehouses of electricity
1800 William Herschel discovers infrared
radiation from the Sun
1801 Johann Ritter discovers ultraviolet
radiation from the Sun
1801 Thomas Young demonstrates the wave nature
of light and the principle of interference
1808 \'Etienne Malus discovers polarization
by reflection
1809 \'Etienne Malus publishes the law of
Malus which predicts the light intensity transmitted by two polarizing
sheets
1811 Fran\c cois Arago discovers that some
quartz crystals will continuously rotate the electric vector of light
1816 David Brewster discovers stress birefringence
1818 Sim\'eon Poisson predicts the Poisson
bright spot at the center of the shadow of a circular opaque obstacle
1818 Fran\c cois Arago verifies the existence
of the Poisson bright spot
1820 Hans Oersted notices that a current
in a wire can deflect a compass needle
1825 Augustin Fresnel phenomenologically
explains optical activity by introducing circular birefringence
1826 Simon Ohm states his law of electrical
resistance
1831 Michael Faraday states his law of induction
1833 Heinrich Lenz states that an induced
current in a closed conducting loop will appear in such a direction that
it opposes the change that
produced it
1845 Michael Faraday discovers that light
propagation in a material can be influenced by external magnetic fields
1849 Armand Fizeau and Jean-Bernard Foucault
measure the speed of light to be about 298,000 km/s
1852 George Stokes defines the Stokes parameters
of polarization
1864 James Clerk Maxwell publishes his papers
on a dynamical theory of the electromagnetic field
1871 Lord Rayleigh discusses the blue sky
law and sunsets
1873 James Clerk Maxwell states that light
is an electromagnetic phenomenon
1875 John Kerr discovers the electrically
induced birefringence of some liquids
1888 Heinrich Hertz discovers radio waves
1895 Wilhelm R\"ontgen discovers X-rays
1896 Arnold Sommerfeld solves the half-plane
diffraction problem
1956 R. Hanbury-Brown and R.Q. Twiss complete
the correlation interferometer
Thermodynamics, Statistical Mechanics, and Random Processes
1761 Joseph Black discovers that ice absorbs
heat without changing temperature when melting
1798 Count Rumford has the idea that heat
is a form of energy
1822 Joseph Fourier formally introduces the
use of dimensions for physical quantities in his {\sevenit Theorie Analytique
de la Chaleur}
1824 Sadi Carnot scientifically analyzes
the efficiency of steam engines
1827 Robert Brown discovers the Brownian
motion of pollen and dye particles in water
1834 Benoit-Pierre Clapeyron presents a formulation
of the second law of thermodynamics
1843 James Joule experimentally finds the
mechanical equivalent of heat
1848 Lord Kelvin discovers the absolute zero
point of temperature
1852 James Joule and Lord Kelvin demonstrate
that a rapidly expanding gas cools
1859 James Clerk Maxwell discovers the distribution
law of molecular velocities
1870 Rudolph Clausius proves the scalar virial
theorem
1872 Ludwig Boltzmann states the Boltzmann
equation for the temporal development of distribution functions in phase
space
1874 Lord Kelvin formally states the second
law of thermodynamics
1876 Josiah Gibbs begins a two-year long
series of papers which discusses phase equilibria, the free energy as the
driving force behind chemical
reactions, and chemical
thermodynamics in general
1879 Josef Stefan observes that the total
radiant flux from a blackbody is proportional to the fourth power of its
temperature
1884 Ludwig Boltzmann derives the Stefan-Boltzmann
blackbody radiant flux law from thermodynamic considerations
1888 Henri-Louis Le Ch\^atelier states that
the response of a chemical system perturbed from equilbrium will be to
counteract the perturbation
1893 Wilhelm Wien discovers the displacement
law for a blackbody's maximum specific intensity
1905 Albert Einstein mathematically analyzes
the Brownian motion
1906 Walther Nernst presents a formulation
of the third law of thermodynamics
1910 Albert Einstein and Marian Smoluchowski
find the Einstein-Smoluchowski formula for the attenuation coefficient
due to density
fluctuations in
a gas
1916 Sydney Chapman and David Enskog systematically
develop a kinetic theory of gases
1919 James Jeans discovers that the dynamical
constants of motion determine the distribution function for a system of
particles
1920 Meghnad Saha states his ionization equation
1923 Pieter Debye and Erich H\"uckel publish
a statistical treatment of the dissociation of electrolytes
1928 J.B. Johnson discovers Johnson noise
in a resistor
1928 Harry Nyquist derives the fluctuation-dissipation
relationship for a resistor to explain Johnson noise
1942 J.L. Doob states his theorem on Gaussian-Markoff
processes
1957 A.S. Kompaneets derives his Compton
scattering Fokker-Planck equation
States of Matter and Phase Transitions
1895 Pierre Curie discovers that induced magnetization
is proportional to magnetic field strength
1911 Heike Kammerlingh Onnes discovers superconductivity
1912 Pieter Debye derives the T-cubed law
for the low temperature heat capacity of a nonmetallic solid
1925 Ernst Ising presents the solution to
the one-dimensional Ising model and models ferromagnetism as a cooperative
spin phenomenon
1933 Walter Meissner and R. Ochsenfeld discover
perfect superconducting diamagnetism
1942 Hannes Alfv\'en predicts magnetohydrodynamic
waves in plasmas
1944 Lars Onsager publishes the exact solution
to the two-dimensional Ising model
1957 John Bardeen, Leon Cooper, and Robert
Schrieffer develop the BCS theory of superconductivity
1958 Rudolf M\"ossbauer finds the M\"ossbauer
crystal recoil effect
1972 Douglas Osheroff, Robert Richardson,
and David Lee discover that helium-3 can become a superfluid
1974 Kenneth Wilson develops the renormalization
group technique for treating phase transitions
1987 Alex M\"uller and Georg Bednorz discover
high critical temperature ceramic superconductors
Quantum Mechanics, Molecular Physics, Atomic Physics, Nuclear Physics, and Particle Physics
-440 Democritus speculates about fundamental
indivisible particles---calls them ``atoms''
1766 Henry Cavendish discovers and studies
hydrogen
1778 Carl Scheele and Antoine Lavoisier discover
that air is composed mostly of nitrogen and oxygen
1781 Joseph Priestly creates water by igniting
hydrogen and oxygen
1800 William Nicholson and Anthony Carlisle
use electrolysis to separate water into hydrogen and oxygen
1803 John Dalton introduces atomic ideas
into chemistry and states that matter is composed of atoms of different
weights
1811 Amedeo Avogadro claims that equal volumes
of gases should contain equal numbers of molecules
1832 Michael Faraday states his laws of electrolysis
1871 Dmitri Mendeleyev systematically examines
the periodic table and predicts the existence of gallium, scandium, and
germanium
1873 Johannes van der Waals introduces the
idea of weak attractive forces between molecules
1885 Johann Balmer finds a mathematical expression
for observed hydrogen line wavelengths
1887 Heinrich Hertz discovers the photoelectric
effect
1894 Lord Rayleigh and William Ramsay discover
argon by spectroscopically analyzing the gas left over after nitrogen and
oxygen are
removed from air
1895 William Ramsay discovers terrestrial
helium by spectroscopically analyzing gas produced by decaying uranium
1896 Antoine Becquerel discovers the radioactivity
of uranium
1896 Pieter Zeeman studies the splitting
of sodium {\sevenit D} lines when sodium is held in a flame between strong
magnetic poles
1897 Joseph Thomson discovers the electron
1898 William Ramsay and Morris Travers discover
neon, krypton, and xenon
1898 Marie Curie and Pierre Curie isolate
and study radium and polonium
1899 Ernest Rutherford discovers that uranium
radiation is composed of positively charged alpha particles and negatively
charged beta particles
1900 Paul Villard discovers gamma-rays while
studying uranium decay
1900 Johannes Rydberg refines the expression
for observed hydrogen line wavelengths
1900 Max Planck states his quantum hypothesis
and blackbody radiation law
1902 Philipp Lenard observes that maximum
photoelectron energies are independent of illuminating intensity but depend
on frequency
1902 Theodor Svedberg suggests that fluctuations
in molecular bombardment cause the Brownian motion
1905 Albert Einstein explains the photoelectric
effect
1906 Charles Barkla discovers that each element
has a characteristic X-ray and that the degree of penetration of these
X-rays is related to
the atomic weight
of the element
1909 Hans Geiger and Ernest Marsden discover
large angle deflections of alpha particles by thin metal foils
1909 Ernest Rutherford and Thomas Royds demonstrate
that alpha particles are doubly ionized helium atoms
1911 Ernest Rutherford explains the Geiger-Marsden
experiment by invoking a nuclear atom model and derives the Rutherford
cross section
1912 Max von Laue suggests using lattice
solids to diffract X-rays
1912 Walter Friedrich and Paul Knipping diffract
X-rays in zinc blende
1913 William Bragg and Lawrence Bragg work
out the Bragg condition for strong X-ray reflection
1913 Henry Moseley shows that nuclear charge
is the real basis for numbering the elements
1913 Niels Bohr presents his quantum model
of the atom
1913 Robert Millikan measures the fundamental
unit of electric charge
1913 Johannes Stark demonstrates that strong
electric fields will split the Balmer spectral line series of hydrogen
1914 James Franck and Gustav Hertz observe
atomic excitation
1914 Ernest Rutherford suggests that the
positively charged atomic nucleus contains protons
1915 Arnold Sommerfeld develops a modified
Bohr atomic model with elliptic orbits to explain relativistic fine structure
1916 Gilbert Lewis and Irving Langmuir formulate
an electron shell model of chemical bonding
1917 Albert Einstein introduces the idea
of stimulated radiation emission
1921 Alfred Land\'e introduces the Lande
g-factor
1922 Arthur Compton studies X-ray photon
scattering by electrons
1922 Otto Stern and Walter Gerlach show ``space
quantization''
1923 Louis de Broglie suggests that electrons
may have wavelike properties
1924 Wolfgang Pauli states the quantum exclusion
principle
1924 John Lennard-Jones proposes a semiempirical
interatomic force law
1924 Satyendra Bose and Albert Einstein introduce
Bose-Einstein statistics
1925 George Uhlenbeck and Samuel Goudsmit
postulate electron spin
1925 Pierre Auger discovers the Auger autoionization
process
1925 Werner Heisenberg, Max Born, and Pascual
Jordan formulate quantum matrix mechanics
1926 Erwin Schr\"odinger states his nonrelativistic
quantum wave equation and formulates quantum wave mechanics
1926 Erwin Schr\"odinger proves that the
wave and matrix formulations of quantum theory are mathematically equivalent
1926 Oskar Klein and Walter Gordon state
their relativistic quantum wave equation
1926 Enrico Fermi discovers the spin-statistics
connection
1926 Paul Dirac introduces Fermi-Dirac statistics
1927 Clinton Davission, Lester Germer, and
George Thomson confirm the wavelike nature of electrons
1927 Werner Heisenberg states the quantum
uncertainty principle
1927 Max Born interprets the probabilistic
nature of wavefunctions
1928 Chandrasekhara Raman studies optical
photon scattering by electrons
1928 Paul Dirac states his relativistic electron
quantum wave equation
1928 Charles G. Darwin and Walter Gordon
solve the Dirac equation for a Coulomb potential
1929 Oskar Klein discovers the Klein paradox
1929 Oskar Klein and Y. Nishina derive the
Klein-Nishina cross section for high energy photon scattering by electrons
1929 N.F. Mott derives the Mott cross section
for the Coulomb scattering of relativistic electrons
1930 Paul Dirac introduces electron hole
theory
1930 Erwin Schr\"odinger predicts the {\sevenit
zitterbewegung} motion
1930 Fritz London explains van der Waals
forces as due to the interacting fluctuating dipole moments between molecules
1931 John Lennard-Jones proposes the Lennard-Jones
interatomic potential
1931 Ir\`ene Joliot-Curie and Fr\'ed\'eric
Joliot-Curie observe but misinterpret neutron scattering in parafin
1931 Wolfgang Pauli puts forth the neutrino
hypothesis to explain the apparent violation of energy conservation in
beta decay
1931 Linus Pauling discovers resonance bonding
and uses it to explain the high stability of symmetric planar molecules
1931 Paul Dirac shows that charge conservation
can be explained if magnetic monopoles exist
1931 Harold Urey discovers deuterium using
evaporation concentration techniques and spectroscopy
1932 John Cockcroft and Thomas Walton split
lithium and boron nuclei using proton bombardment
1932 James Chadwick discovers the neutron
1932 Werner Heisenberg presents the proton-neutron
model of the nucleus and uses it to explain isotopes
1932 Carl Anderson discovers the positron
1933 Max Delbr\"uck suggests that quantum
effects will cause photons to be scattered by an external electric field
1934 Ir\`ene Joliot-Curie and Fr\'ed\'eric
Joliot-Curie bombard aluminum atoms with alpha particles to create artificially
radioactive
phosphorus-30
1934 Leo Szilard realizes that nuclear chain
reactions may be possible
1934 Enrico Fermi formulates his theory of
beta decay
1934 Lev Landau tells Edward Teller that
nonlinear molecules may have vibrational modes which remove the degeneracy
of an orbitally
degenerate state
1934 Enrico Fermi suggests bombarding uranium
atoms with neutrons to make a 93 proton element
1934 Pavel \v Cerenkov reports that light
is emitted by relativistic particles traveling in a nonscintillating liquid
1935 Hideki Yukawa presents a theory of strong
interactions and predicts mesons
1935 Albert Einstein, Boris Podolsky, and
Nathan Rosen put forth the EPR paradox
1935 Niels Bohr presents his analysis of
the EPR paradox
1936 Eugene Wigner develops the theory of
neutron absorption by atomic nuclei
1936 Hans Jahn and Edward Teller present
their systematic study of the symmetry types for which the Jahn-Teller
effect is expected
1937 H. Hellmann finds the Hellmann-Feynman
theorem
1937 Seth Neddermeyer, Carl Anderson, J.C.
Street, and E.C. Stevenson discover muons using cloud chamber measurements
of cosmic rays
1939 Richard Feynman finds the Hellmann-Feynman
theorem
1939 Otto Hahn and Fritz Strassman bombard
uranium salts with thermal neutrons and discover barium among the reaction
products
1939 Lise Meitner and Otto Frisch determine
that nuclear fission is taking place in the Hahn-Strassman experiments
1942 Enrico Fermi makes the first controlled
nuclear chain reaction
1942 Ernst St\"uckelberg introduces the propagator
to positron theory and interprets positrons as negative energy electrons
moving
backwards through
spacetime
1943 Sin-Itiro Tomonaga publishes his paper
on the basic physical principles of quantum electrodynamics
1947 Willis Lamb and Robert Retheford measure
the Lamb-Retheford shift
1947 Cecil Powell, C.M.G. Lattes, and G.P.S.
Occhialini discover the pi-meson by studying cosmic ray tracks
1947 Richard Feynman presents his propagator
approach to quantum electrodynamics
1948 Hendrik Casimir predicts a rudimentary
attractive Casimir force on a parallel plate capacitor
1951 Martin Deutsch discovers positronium
1953 R. Wilson observes Delbr\"uck scattering
of 1.33 MeV gamma-rays by the electric fields of lead nuclei
1954 Chen Yang and Robert Mills investigate
a theory of hadronic isospin by demanding local gauge invariance under
isotopic spin space
rotations---first
non-Abelian gauge theory
1955 Owen Chamberlain, Emilio Segr\`e, Clyde
Wiegand, and Thomas Ypsilantis discover the antiproton
1956 Frederick Reines and Clyde Cowan detect
antineutrinos
1956 Chen Yang and Tsung Lee propose parity
violation by the weak force
1956 Chien Shiung Wu discovers parity violation
by the weak force in decaying cobalt
1957 Gerhart L\"uders proves the CPT theorem
1957 Richard Feynman, Murray Gell-Mann, Robert
Marshak, and Ennackel Sudarshan propose a V-A Lagrangian for weak interactions
1958 Marcus Sparnaay experimentally confirms
the Casimir effect
1959 Yakir Aharonov and David Bohm predict
the Aharonov-Bohm effect
1960 R.G. Chambers experimentally confirms
the Aharonov-Bohm effect
1961 Murray Gell-Mann and Yuval Ne'eman discover
the Eightfold Way patterns---SU(3) group
1961 Jeffery Goldstone considers the breaking
of global phase symmetry
1962 Leon Lederman shows that the electron
neutrino is distinct from the muon neutrino
1963 Murray Gell-Mann and George Zweig propose
the quark/aces model
1964 Peter Higgs considers the breaking of
local phase symmetry
1964 J.S. Bell shows that all local hidden
variable theories must satisfy Bell's inequality
1964 Val Fitch and James Cronin observe CP
violation by the weak force in the decay of K mesons
1967 Steven Weinberg puts forth his electroweak
model of leptons
1969 J.C. Clauser, M. Horne, A. Shimony,
and R. Holt propose a polarization correlation test of Bell's inequality
1970 Sheldon Glashow, John Iliopoulos, and
Luciano Maiani propose the charm quark
1971 Gerard 't Hooft shows that the Glashow-Salam-Weinberg
electroweak model can be renormalized
1972 S. Freedman and J.C. Clauser perform
the first polarization correlation test of Bell's inequality
1973 David Politzer proposes the asymptotic
freedom of quarks
1974 Burton Richter and Samuel Ting discover
the {\sevenit J}/$\psi$ meson implying the existence of the charm quark
1975 Martin Perl discovers the tauon
1977 S.W. Herb finds the upsilon resonance
implying the existence of the beauty quark
1982 A. Aspect, J. Dalibard, and G. Roger
perform a polarization correlation test of Bell's inequality that rules
out conspiratorial
polarizer communication
1983 Carlo Rubbia, Simon van der Meer, and
the CERN UA-1 collaboration find the W$^\pm$ and Z$^0$ intermediate vector
bosons
1989 The Z$^0$ intermediate vector boson
resonance width indicates three quark-lepton generations
1896 Charles Wilson discovers that energetic
particles produce droplet tracks in supersaturated gases
1908 Hans Geiger and Ernest Rutherford invent
the Geiger counter
1911 Charles Wilson finishes a sophisticated
cloud chamber
1934 Ernest Lawrence and Stan Livingston
invent the cyclotron
1945 Edwin McMillan devises a synchrotron
1952 Donald Glaser develops the bubble chamber
1968 Georges Charpak and Roger Bouclier build
the first multiwire proportional mode particle detection chamber
Gravitational Physics and Relativity
1640 Ismael Bullialdus suggests an inverse-square
gravitational force law
1665 Isaac Newton deduces the inverse-square
gravitational force law from the ``falling'' of the Moon
1684 Isaac Newton proves that planets moving
under an inverse-square force law will obey Kepler's laws
1686 Isaac Newton uses a fixed length pendulum
with weights of varying composition to test the weak equivalence principle
to 1 part in 1000
1798 Henry Cavendish measures the gravitational
constant
1845 Urbain Leverrier observes a 35'' per
century excess precession of Mercury's orbit
1876 William Clifford suggests that the motion
of matter may be due to changes in the geometry of space
1882 Simon Newcomb observes a 43'' per century
excess precession of Mercury's orbit
1887 Albert Michelson and Edward Morley do
not detect the ether drift
1889 Roland von E\"otv\"os uses a torsion
fiber balance to test the weak equivalence principle to 1 part in one billion
1893 Ernst Mach states Mach's principle---first
constructive attack on the idea of Newtonian absolute space
1905 Albert Einstein completes his theory
of special relativity and states the law of mass-energy conservation
1907 Albert Einstein introduces the principle
of equivalence of gravitation and inertia and uses it to predict the gravitational
redshift
1915 Albert Einstein completes his theory
of general relativity
1916 Albert Einstein shows that the field
equations of general relativity admit wavelike solutions
1918 J. Lense and Hans Thirring find the
gravitomagnetic precession of gyroscopes in the equations of general relativity
1919 Arthur Eddington leads a solar eclipse
expedition which claims to detect gravitational deflection of light by
the Sun
1921 T. Kaluza demonstrates that a five-dimensional
version of Einstein's equations unifies gravitation and electromagnetism
1937 Fritz Zwicky states that galaxies could
act as gravitational lenses
1937 Albert Einstein, Leopold Infeld, and
Banesh Hoffman show that the geodesic equations of general relativity can
be deduced from
its field equations
1957 John Wheeler discusses the breakdown
of classical general relativity near singularities and the need for quantum
gravity
1960 Robert Pound and Glen Rebka test the
gravitational redshift predicted by the equivalence principle to approximately
1\%
1962 Robert Dicke, Peter Roll, and R. Krotkov
use a torsion fiber balance to test the weak equivalence principle to 2
parts in 100 billion
1964 Irwin Shapiro predicts a gravitational
time delay of radiation travel as a test of general relativity
1965 Joseph Weber puts the first Weber bar
gravitational wave detector into operation
1968 Irwin Shapiro presents the first detection
of the Shapiro delay
1968 Kenneth Nordtvedt studies a possible
violation of the weak equivalence principle for self-gravitating bodies
and proposes a new test
of the weak equivalence
principle based on observing the relative motion of the Earth and Moon
in the Sun's gravitational field
1976 Robert Vessot and Martin Levine use
a hydrogen maser clock on a Scout D rocket to test the gravitational redshift
predicted by
the equivalence
principle to approximately 0.007\%
1979 Dennis Walsh, Robert Carswell, and Ray
Weymann discover the gravitationally lensed quasar Q0957+561
1982 Joseph Taylor and Joel Weisberg show
that the rate of energy loss from the binary pulsar PSR1913+16 agrees with
that predicted by
the general relativistic
quadrupole formula to within 5\%
1784 John Michell discusses classical bodies
which have escape velocities greater than the speed of light
1795 Pierre Laplace discusses classical bodies
which have escape velocities greater than the speed of light
1916 Karl Schwarzschild solves the Einstein
vacuum field equations for uncharged spherically symmetric systems
1918 H. Reissner and G. Nordstr\o m solve
the Einstein-Maxwell field equations for charged spherically symmetric
systems
1923 George Birkhoff proves that the Schwarzschild
spacetime geometry is the unique spherically symmetric solution of the
Einstein
vacuum field equations
1939 Robert Oppenheimer and Hartland Snyder
calculate the collapse of a pressure-free homogeneous fluid sphere and
find that it cuts
itself off from
communication with the rest of the universe
1963 Roy Kerr solves the Einstein vacuum
field equations for uncharged rotating systems
1964 Roger Penrose proves that an imploding
star will necessarily produce a singularity once it has formed an event
horizon
1965 Ezra Newman, E. Couch, K. Chinnapared,
A. Exton, A. Prakash, and Robert Torrence solve the Einstein-Maxwell field
equations for
charged rotating
systems
1968 Brandon Carter uses Hamilton-Jacobi
theory to derive first-order equations of motion for a charged particle
moving in the external
fields of a Kerr-Newman
black hole
1969 Roger Penrose discusses the Penrose
process for the extraction of the spin energy from a Kerr black hole
1969 Roger Penrose proposes the cosmic censorship
hypothesis
1971 Identification of Cygnus X-1/HDE 226868
as a binary black hole candidate system
1972 Stephen Hawking proves that the area
of a classical black hole's event horizon cannot decrease
1972 James Bardeen, Brandon Carter, and Stephen
Hawking propose four laws of black hole mechanics in analogy with the
laws of thermodynamics
1972 Jacob Bekenstein suggests that black
holes have an entropy proportional to their surface area due to information
loss effects
1974 Stephen Hawking applies quantum field
theory to black hole spacetimes and shows that black holes will radiate
particles with
a blackbody spectrum
which can cause black hole evaporation
1989 Identification of GS2023+338/V404 Cygni
as a binary black hole candidate system
1576 Thomas Digges modifies the Copernican
system by removing its outer edge and replacing the edge with a star filled
unbounded space
1610 Johannes Kepler uses the dark night
sky to argue for a finite universe
1720 Edmund Halley puts forth an early form
of Olbers' paradox
1744 Jean-Phillipe de Cheseaux puts forth
an early form of Olbers' paradox
1826 Heinrich Olbers puts forth Olbers' paradox
1917 Willem de Sitter derives an isotropic
static cosmology with a cosmological constant as well as an empty expanding
cosmology with a
cosmological constant
1922 Vesto Slipher summarizes his findings
on the spiral nebulae's systematic redshifts
1922 Alexander Friedmann finds a solution
to the Einstein field equations which suggests a general expansion of space
1927 Georges-Henri Lema\^\i tre discusses
the creation event of an expanding universe governed by the Einstein field
equations
1928 Harold Robertson briefly mentions that
Vesto Slipher's redshift measurements combined with brightness measurements
of the same
galaxies indicate
a redshift-distance relation
1929 Edwin Hubble demonstrates the linear
redshift-distance relation and thus shows the expansion of the universe
1933 Edward Milne names and formalizes the
cosmological principle
1934 Georges-Henri Lema\^\i tre interprets
the cosmological constant as due to a ``vacuum'' energy with an unusual
perfect fluid equation of state
1938 Paul Dirac presents a cosmological theory
where the gravitational constant decreases slowly so that the age of the
universe divided by the
atomic light-crossing
time always equals the ratio of the electric force to the gravitational
force between a proton and electron
1948 Ralph Alpher, Hans Bethe, and George
Gamow examine element synthesis in a rapidly expanding and cooling universe
and suggest that
the elements were
produced by rapid neutron capture
1948 Hermann Bondi, Thomas Gold, and Fred
Hoyle propose steady state cosmologies based on the perfect cosmological
principle
1951 William McCrea shows that the steady
state C-field can be accommodated within general relativity by interpreting
it as a
contribution to
the energy-momentum tensor with an unusual equation of state
1961 Robert Dicke argues that carbon-based
life can only arise when the Dirac large numbers hypothesis is true because
this is when burning
stars exist---first
use of the weak anthropic principle
1963 Fred Hoyle and Jayant Narlikar show
that the steady state theory can explain the isotropy of the universe because
deviations from
isotropy and homogeneity
exponentially decay in time
1964 Fred Hoyle and Roger Tayler point out
that the primordial helium abundance depends on the number of neutrinos
1965 Martin Rees and Dennis Sciama analyze
quasar source count data and discover that the quasar density increases
with redshift
1965 Edward Harrison resolves Olbers' paradox
by noting the finite lifetime of stars
1966 Stephen Hawking and George Ellis show
that any plausible general relativistic cosmology is singular
1966 Jim Peebles shows that the hot Big Bang
predicts the correct helium abundance
1967 Andrey Sakharov presents the requirements
for a baryon-antibaryon asymmetry in the universe
1967 John Bahcall, Wal Sargent, and Maarten
Schmidt measure the fine-structure splitting of spectral lines in 3C191
and thereby show that
the fine-structure
constant does not vary significantly with time
1968 Brandon Carter speculates that perhaps
the fundamental constants of nature must lie within a restricted range
to allow the emergence
of life---first
use of the strong anthropic principle
1969 Charles Misner formally presents the
Big Bang horizon problem
1969 Robert Dicke formally presents the Big
Bang flatness problem
1973 Edward Tryon proposes that the universe
may be a large scale quantum mechanical vacuum fluctuation where positive
mass-energy
is balanced by negative
gravitational potential energy
1974 Robert Wagoner, William Fowler, and
Fred Hoyle show that the hot Big Bang predicts the correct deuterium and
lithium abundances
1976 A.I. Shlyakhter uses samarium ratios
from the prehistoric natural fission reactor in Gabon to show that some
laws of physics have
remained unchanged
for over two billion years
1977 Gary Steigman, David Schramm, and James
Gunn examine the relation between the primordial helium abundance and number
of neutrinos
and claim that at
most five lepton families can exist
1980 Alan Guth proposes the inflationary
Big Bang universe as a possible solution to the horizon and flatness problems
Cosmic Microwave Background Astronomy
1934 Richard Tolman shows that blackbody radiation
in an expanding universe cools but remains thermal
1941 Andrew McKellar uses the excitation
of CN doublet lines to measure that the ``effective temperature of space''
is about 2.3 K
1948 George Gamow, Ralph Alpher, and Robert
Herman predict that a Big Bang universe will have a blackbody cosmic microwave
background with
temperature about 5 K
1955 Tigran Shmaonov finds excess microwave
emission with a temperature of roughly 3 K
1964 A.G. Doroshkevich and Igor Novikov write
an unnoticed paper suggesting microwave searches for the blackbody radiation
predicted
by Gamow, Alpher,
and Herman
1965 Arno Penzias, Robert Wilson, Bernie
Burke, Robert Dicke, and James Peebles discover the cosmic microwave background
radiation
1966 Rainer Sachs and Arthur Wolfe theoretically
predict microwave background fluctuation amplitudes created by gravitational
potential variations
between observers and the last scattering surface
1968 Martin Rees and Dennis Sciama theoretically
predict microwave background fluctuation amplitudes created by photons
traversing
time-dependent potential
wells
1969 R.A. Sunyaev and Yakov Zel'dovich study
the inverse Compton scattering of microwave background photons by hot electrons
1990 The COBE satellite shows that the microwave
background has a nearly perfect blackbody spectrum and thereby strongly
constrains
the density of the
intergalactic medium
1992 The COBE satellite discovers anisotropy
in the cosmic microwave background
Other Background Radiation Fields
1912 Victor Hess discovers that the ionization
of air increases with altitude indicating the existence of cosmic radiation
1956 Herbert Friedman detects evidence for
extrasolar X-rays
1962 Riccardo Giacconi, Herbert Gursky, F.
Paolini, and Bruno Rossi formally discover the X-ray background
Galaxies, Clusters of Galaxies, and Large Scale Structure
1521 Ferdinand Magellan observes the Magellanic
Clouds during his circumnavigating expedition
1750 Thomas Wright discusses galaxies and
the shape of the Milky Way
1845 Lord Rosse discovers a nebula with a
distinct spiral shape
1918 Harlow Shapley demonstrates that globular
clusters surround our galaxy like a halo and are not centered on the Earth
1920 Harlow Shapely and Heber Curtis debate
whether or not the spiral nebulae lie within the Milky Way
1923 Edwin Hubble resolves the Shapely-Curtis
debate by finding Cepheids in Andromeda
1932 Karl Jansky discovers radio noise from
the center of the Milky Way
1933 Fritz Zwicky applies the virial theorem
to the Coma cluster and obtains evidence for unseen mass
1936 Edwin Hubble introduces the spiral,
barred spiral, elliptical, and irregular galaxy classifications
1939 Grote Reber discovers the radio source
Cygnus A
1943 Carl Seyfert identifies six spiral galaxies
with unusually broad emission lines
1949 J.G. Bolton, G.J. Stanley, and O.B.
Slee identify NGC 4486 (M87) and NGC 5128 as extragalactic radio sources
1953 G\'erard de Vaucouleurs discovers that
the galaxies within approximately 200 million light years of the Virgo
cluster are
confined to a giant
supercluster disk
1954 Walter Baade and Rudolph Minkowski identify
the extragalactic optical counterpart of the radio source Cygnus A
1960 Thomas Matthews determines the radio
position of 3C48 to within 5''
1960 Allan Sandage optically studies 3C48
and observes an unusual blue quasi stellar object
1962 Cyril Hazard, M.B. Mackey, and A.J.
Shimmins use lunar occultations to determine a precise position for 3C273
and deduce that
it is a double source
1963 Maarten Schmidt identifies the redshifted
Balmer lines from the quasar 3C273
1973 Jeremiah Ostriker and James 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 B.L. Fanaroff and J.M. Riley distinguish
between edge-darkened (FR I) and edge-brightened (FR II) radio sources
1976 Sandra Faber and Robert Jackson discover
the Faber-Jackson relation between the luminosity of an elliptical galaxy
and the
velocity dispersion
in its center
1977 Brent Tully and Richard Fisher discover
the Tully-Fisher relation between the luminosity of an isolated spiral
galaxy and the
velocity of the
flat part of its rotation curve
1978 Steve Gregory and Laird Thompson describe
the Coma supercluster
1978 Vera Rubin, Kent Ford, N. Thonnard,
and Albert Bosma measure the rotation curves of several spiral galaxies
and find significant
deviations from
what is predicted by the Newtonian gravitation of visible stars
1981 Robert Kirshner, August Oemler, Paul
Schechter, and Stephen Shectman find evidence for a giant void in Bo\"otes
with a diameter
of approximately
100 million light years
1985 Robert Antonucci and J. Miller discover
that the Seyfert II galaxy NGC 1068 has broad lines which can only be seen
in polarized
reflected light
1986 Amos Yahil, David Walker, and Michael
Rowan-Robinson find that the direction of the IRAS galaxy density dipole
agrees with the
direction of the
cosmic microwave background temperature dipole
1987 David Burstein, Roger Davies, Alan Dressler,
Sandra Faber, Donald Lynden-Bell, R.J. Terlevich, and Gary 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''
1990 Michael Rowan-Robinson and Tom Broadhurst
discover that the IRAS galaxy F10214+4724 is the brightest known object
in the universe
The Interstellar Medium and Intergalactic Medium
1848 Lord Rosse studies M1 and names it the
Crab Nebula
1864 William Huggins studies the spectrum
of the Orion Nebula and shows that it is a cloud of gas
1927 Ira Bowen explains unidentified spectral
lines from space as forbidden transition lines
1930 Robert Trumpler discovers absorption
by interstellar dust by comparing the angular sizes and brightnesses of
globular clusters
1944 Hendrik van de Hulst predicts the 21
cm hyperfine line of neutral interstellar hydrogen
1951 H.I. Ewen and Edward Purcell observe
the 21 cm hyperfine line of neutral interstellar hydrogen
1956 Lyman Spitzer predicts coronal gas around
the Milky Way
1965 James Gunn and Bruce Peterson use observations
of the relatively low absorption of the blue component of the Lyman-alpha
line
from 3C9 to strongly
constrain the density and ionization state of the intergalactic medium
1969 Lewis Snyder, David Buhl, Ben Zuckerman,
and Patrick Palmer find interstellar formaldehyde
1970 Arno Penzias and Robert Wilson find
interstellar carbon monoxide
1970 George Carruthers observes molecular
hydrogen in space
1977 Christopher McKee and Jeremiah Ostriker
propose a three component theory of the interstellar medium
White Dwarfs, Neutron Stars, and Supernovae
1054 Chinese and American Indian astronomers
observe the Crab supernova explosion
1572 Tycho Brahe discovers his supernova
in Cassiopeia
1604 Johannes Kepler's supernova in Serpens
is observed
1862 Alvan Clark observes Sirius B
1866 William Huggins studies the spectrum
of a nova and discovers that it is surrounded by a cloud of hydrogen
1914 Walter Adams determines an incredibly
high density for Sirius B
1926 Ralph Fowler uses Fermi-Dirac statistics
to explain white dwarf stars
1930 Subrahmanyan Chandrasekhar discovers
the white dwarf maximum mass limit
1933 Fritz Zwicky and Walter 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
1939 Robert Oppenheimer and George Volkoff
calculate the first neutron star models
1942 J.J.L. Duyvendak, Nicholas Mayall, and
Jan Oort deduce that the Crab Nebula is a remnant of the 1054 supernova
observed by Chinese
astronomers
1958 Evry Schatzman, Kent Harrison, Masami
Wakano, and John Wheeler show that white dwarfs are unstable to inverse
beta decay
1962 Riccardo Giacconi, Herbert Gursky, Frank
Paolini, and Bruno Rossi discover Sco X-1
1967 Jocelyn Bell and Anthony Hewish discover
radio pulses from a pulsar
1967 J.R. Harries, Ken McCracken, R.J. Francey,
and A.G. Fenton discover the first X-ray transient (Cen X-2)
1968 Thomas Gold proposes that pulsars are
rotating neutron stars
1969 David Staelin, E.C. Reifenstein, William
Cocke, Mike Disney, and Donald Taylor discover the Crab Nebula pulsar thus
connecting
supernovae, neutron
stars, and pulsars
1971 Riccardo Giacconi, Herbert Gursky, Ed
Kellogg, R. Levinson, E. Schreier, and H. Tananbaum discover 4.8 second
X-ray pulsations
from Cen X-3
1974 Russell Hulse and Joseph Taylor discover
the binary pulsar PSR1913+16
1977 Kip Thorne and Anna \.Zytkow present
a detailed analysis of Thorne-\.Zytkow objects
1982 D.C. Backer, Shrinivas Kulkarni, Carl
Heiles, M.M. Davis, and Miller Goss discover the millisecond pulsar PSR1937+214
1985 Michiel van der Klis discovers 30 Hz
quasi-periodic oscillations in GX 5-1
1987 Ian Shelton discovers supernova 1987A
in the Large Magellanic Cloud
-134 Hipparchus creates the magnitude scale
of stellar apparent luminosities
1596 David Fabricus notices that Mira's brightness
varies
1672 Geminiano Montanari notices that Algol's
brightness varies
1686 Gottfried Kirch notices that Chi Cygni's
brightness varies
1718 Edmund Halley discovers stellar proper
motions by comparing his astrometric measurements with those of the Greeks
1782 John Goodricke notices that the brightness
variations of Algol are periodic and proposes that it is partially eclipsed
by a body
moving around it
1784 Edward Piggot discovers the first Cepheid
variable star
1838 Thomas Henderson, Friedrich Struve,
and Friedrich Bessel measure stellar parallaxes
1844 Friedrich Bessel explains the wobbling
motions of Sirius and Procyon by suggesting that these stars have dark
companions
1906 Arthur Eddington begins his statistical
study of stellar motions
1908 Henrietta Leavitt discovers the Cepheid
period-luminosity relation
1910 Ejnar Hertzsprung and Henry Russell
study the relation between magnitudes and spectral types of stars
1924 Arthur Eddington develops the main-sequence
mass-luminosity relationship
1929 George Gamow proposes hydrogen fusion
as the energy source for stars
1938 Hans Bethe and Carl von Weizs\"acker
detail the proton-proton chain and CNO cycle in stars
1939 Rupert Wildt realizes the importance
of the negative hydrogen ion for stellar opacity
1952 Walter Baade distinguishes between Cepheid
I and Cepheid II variable stars
1953 Fred Hoyle predicts a carbon-12 resonance
to allow stellar triple alpha reactions at reasonable stellar interior
temperatures
1961 Chushiro Hayashi publishes his work
on the Hayashi track of fully convective stars
1963 Fred Hoyle and William Fowler conceive
the idea of supermassive stars
1964 Subrahmanyan Chandrasekhar and Richard
Feynman develop a general relativistic theory of stellar pulsations and
show that
supermassive stars
are subject to a general relativistic instability
1967 Gerry Neugebauer and Eric Becklin discover
the Becklin-Neugebauer object at 10 microns
1613 Galileo Galilei uses sunspot observations
to demonstrate the rotation of the Sun
1619 Johannes Kepler postulates a solar wind
to explain the direction of comet tails
1802 William Wollaston observes dark lines
in the solar spectrum
1814 Joseph Fraunhofer systematically studies
the dark lines in the solar spectrum
1834 Hermann Helmholtz proposes gravitational
contraction as the energy source for the Sun
1843 Heinrich Schwabe announces his discovery
of the sunspot cycle and estimates its period to be about ten years
1852 Edward Sabine shows that sunspot number
is correlated with geomagnetic field variations
1859 Richard Carrington discovers solar flares
1860 Gustav Kirchoff and Robert Bunsen discover
that each element has its own distinct set of spectral lines and use this
fact to explain
the solar dark lines
1861 F.G.W. Sp\"orer discovers the variation
of sunspot latitudes during a solar cycle
1863 Richard Carrington discovers the differential
nature of solar rotation
1868 Pierre-Jules-C\'esar Janssen and Norman
Lockyer discover an unidentified yellow line in solar prominence spectra
and suggest it
comes from a new
element which they name ``helium''
1893 Edward Maunder discovers the 1645--1715
Maunder sunspot minimum
1904 Edward Maunder plots the first sunspot
``butterfly diagram''
1906 Karl Schwarzschild explains solar limb
darkening
1908 George Hale discovers the Zeeman splitting
of spectral lines from sunspots
1942 J.S. Hey detects solar radio waves
1949 Herbert Friedman detects solar X-rays
1960 Robert Leighton, Robert Noyes, and George
Simon discover solar five-minute oscillations by observing the Doppler
shifts of solar
dark lines
1961 H. Babcock proposes the magnetic coiling
sunspot theory
1970 Roger Ulrich, John Leibacher, and Robert
Stein deduce from theoretical solar models that the interior of the Sun
could act as a
resonant acoustic
cavity
1975 Franz-Ludwig Deubner makes the first
accurate measurements of the period and horizontal wavelength of the five-minute
solar oscillations
-2136 Chinese astronomers record a solar eclipse
-586 Thales of Miletus predicts a solar eclipse
-350 Aristotle argues for a spherical Earth
using lunar eclipses and other observations
-280 Aristarchus uses the size of the Earth's
shadow on the Moon to estimate that the Moon's radius is one-third that
of the Earth
-200 Eratosthenes uses shadows to determine
that the radius of the Earth is roughly 6,400 km
-150 Hipparchus uses parallax to determine
that the distance to the Moon is roughly 380,000 km
-134 Hipparchus discovers the precession
of the equinoxes
1512 Nicholas Copernicus first states his
heliocentric theory in {\sevenit Commentariolus}
1543 Nicholas Copernicus shows that his heliocentric
theory simplifies planetary motion tables in {\sevenit De Revolutionibus
de Orbium Coelestium}
1577 Tycho Brahe uses parallax to prove that
comets are distant entities and not atmospheric phenomena
1609 Johannes Kepler states his first two
empirical laws of planetary motion
1610 Galileo Galilei discovers Callisto,
Europa, Ganymede, and Io
1610 Galileo Galilei sees Saturn's rings
but does not recognize that they are rings
1619 Johannes Kepler states his third empirical
law of planetary motion
1655 Giovanni Cassini discovers Jupiter's
great red spot
1656 Christian Huygens identifies Saturn's
rings as rings and discovers Titan and the Orion Nebula
1665 Giovanni Cassini determines the rotational
speeds of Jupiter, Mars, and Venus
1672 Giovanni Cassini discovers Rhea
1672 Jean Richer and Giovanni Cassini measure
the astronomical unit to be about 138,370,000 km
1675 Ole R\"omer uses the orbital mechanics
of Jupiter's moons to estimate that the speed of light is about 227,000
km/s
1705 Edmund Halley publicly predicts the
periodicity of Halley's comet and computes its expected path of return
in 1758
1715 Edmund Halley calculates the shadow
path of a solar eclipse
1716 Edmund Halley suggests a high-precision
measurement of the Sun-Earth distance by timing the transit of Venus
1758 Johann Palitzsch observes the return
of Halley's comet
1766 Johann Titius finds the Titius-Bode
rule for planetary distances
1772 Johann Bode publicizes the Titius-Bode
rule for planetary distances
1781 William Herschel discovers Uranus during
a telescopic survey of the northern sky
1796 Pierre Laplace states his nebular hypothesis
for the formation of the solar system from a spinning nebula of gas and
dust
1801 Giuseppe Piazzi discovers the asteroid
Ceres
1802 Heinrich Olbers discovers the asteroid
Pallas
1821 Alexis Bouvard detects irregularities
in the orbit of Uranus
1825 Pierre Laplace completes his study of
gravitation, the stability of the solar system, tides, the precession of
the equinoxes, the
libration of the
Moon, and Saturn's rings in {\sevenit M\'ecanique C\'eleste}
1843 John Adams predicts the existence and
location of Neptune from irregularities in the orbit of Uranus
1846 Urbain Leverrier predicts the existence
and location of Neptune from irregularities in the orbit of Uranus
1846 Johann Galle discovers Neptune
1846 William Lassell discovers Triton
1849 Edouard Roche finds the limiting radius
of tidal destruction and tidal creation for a body held together only by
its self gravity
and uses it to explain
why Saturn's rings do not condense into a satellite
1856 James Clerk Maxwell demonstrates that
a solid ring around Saturn would be torn apart by gravitational forces
and argues that
Saturn's rings consist
of a multitude of tiny satellites
1866 Giovanni Schiaparelli realizes that
meteor streams occur when the Earth passes through the orbit of a comet
that has left debris
along its path
1906 Max Wolf discovers the Trojan asteroid
Achilles
1930 Clyde Tombaugh discovers Pluto
1930 Seth Nicholson measures the surface
temperature of the Moon
1950 Jan Oort suggests the presence of a
cometary Oort cloud
1951 Gerard Kuiper argues for an annular
reservoir of comets between 40--100 astronomical units from the Sun
1977 James Elliot discovers the rings of
Uranus during a stellar occultation experiment on the Kuiper Airborne Observatory
1978 James Christy discovers Charon
1978 Peter Goldreich and Scott Tremaine present
a Boltzmann equation model of planetary-ring dynamics for indestructible
spherical ring
particles that do
not self-gravitate and find a stability requirement relation between ring
optical depth and particle normal
restitution coefficient
1988 Martin Duncan, Thomas Quinn, and Scott
Tremaine demonstrate that short-period comets come primarily from the Kuiper
Belt and not
the Oort cloud
Astronomical Maps, Catalogs, and Surveys
-134 Hipparchus makes a detailed star map
1678 Edmund Halley publishes a catalog of
341 southern stars---first systematic southern sky survey
1771 Charles Messier publishes his first
list of nebulae
1864 John Herschel publishes the {\sevenit
General Catalog} of nebulae and star clusters
1890 John Dreyer publishes the {\sevenit
New General Catalog} of nebulae and star clusters
1956 Completion of the Palomar sky survey
with the Palomar 48-inch Schmidt optical reflecting telescope
1962 A.S. Bennett publishes the {\sevenit
Revised 3C Catalog} of 328 radio sources
1965 Gerry Neugebauer and Robert Leighton
begin a 2.2 micron sky survey with a 1.6-meter telescope on Mount Wilson
1993 Start of the 20 cm VLA FIRST survey
Telescopes, Observatories, and Observing Technology
1608 Hans Lippershey tries to patent an optical
refracting telescope
1609 Galileo Galilei builds his first optical
refracting telescope
1641 William Gascoigne invents telescope
cross hairs
1661 James Gregory proposes an optical reflecting
telescope
1668 Isaac Newton constructs the first optical
reflecting telescope
1733 Chester Moor Hall invents the achromatic
lens refracting telescope
1758 John Dolland reinvents the achromatic
lens
1789 William Herschel finishes a 49-inch
optical reflecting telescope---located in Slough, England
1840 J.W. Draper invents astronomical photography
and photographs the Moon
1845 Lord Rosse finishes the Birr Castle
72-inch optical reflecting telescope---located in Parsonstown, Ireland
1872 Henry Draper invents astronomical spectral
photography and photographs the spectrum of Vega
1890 Albert Michelson proposes the stellar
interferometer
1892 George Hale finishes a spectroheliograph---allows
the Sun to be photographed in the light of one element only
1897 Alvan Clark finishes the Yerkes 40-inch
optical refracting telescope---located in Williams Bay, Wisconsin
1917 Mount Wilson 100-inch optical reflecting
telescope begins operation---located in Mount Wilson, California
1930 Bernard-Ferdinand Lyot invents the coronagraph
1930 Karl Jansky builds a 30-meter long rotating
aerial radio telescope
1933 Bernard-Ferdinand Lyot invents the Lyot
filter
1934 Bernhard Schmidt finishes the first
14-inch Schmidt optical reflecting telescope
1936 Palomar 18-inch Schmidt optical reflecting
telescope begins operation---located in Palomar, California
1937 Grote Reber builds a 31-foot radio telescope
1947 Bernard Lovell and his group complete
the Jodrell Bank 218-foot non-steerable radio telescope
1949 Palomar 48-inch Schmidt optical reflecting
telescope begins operation---located in Palomar, California
1949 Palomar 200-inch optical reflecting
telescope begins regular operation---located in Palomar, California
1957 Bernard Lovell and his group complete
the Jodrell Bank 250-foot steerable radio telescope
1957 Peter Scheuer publishes his {\sevenit
P(D)} method for obtaining source counts of spatially unresolved sources
1960 Martin Ryle tests Earth rotation aperature
synthesis
1960 Owens Valley 27-meter radio telescopes
begin operation---located in Big Pine, California
1963 Arecibo 300-meter radio telescope begins
operation---located in Arecibo, Puerto Rico
1964 Ryle 1-mile radio interferometer begins
operation---located in Cambridge, England
1965 Owens Valley 40-meter radio telescope
begins operation---located in Big Pine, California
1967 First VLBI images---183 km baseline
1969 Observations start at Big Bear Solar
Observatory---located in Big Bear, California
1970 Cerro Tololo 158-inch optical reflecting
telescope begins operation---located in Cerro Tololo, Chile
1970 Kitt Peak National Observatory 158-inch
optical reflecting telescope begins operation---located near Tucson, Arizona
1974 Anglo-Australian 153-inch optical reflecting
telescope begins operation---located in Siding Springs, Australia
1975 Gerald Smith, Frederick Landauer, and
James Janesick use a CCD to observe Uranus---first astronomical CCD observation
1978 Multiple Mirror 176-inch equivalent
optical/infrared reflecting telescope begins operation---located in Amado,
Arizona
1979 UKIRT 150-inch infrared reflecting telescope
begins operation---located at Mauna Kea, Hawaii
1979 Canada-France-Hawaii 140-inch optical
reflecting telescope begins operation---located at Mauna Kea, Hawaii
1980 Completion of construction of the VLA---located
in Socorro, New Mexico
1993 Keck 10-meter optical/infrared reflecting
telescope begins operation---located at Mauna Kea, Hawaii
Artificial Satellites and Space Probes
1957 {\sevenit Sputnik I} is launched---first
orbiting satellite
1962 {\sevenit Mariner 2} is the first mission
to Venus
1965 {\sevenit Mariner 4} sends the first
clear pictures of Mars
1966 {\sevenit Luna 10} becomes the first
spacecraft to orbit the Moon
1967 {\sevenit Venera 4} sends the first
data from below the clouds of Venus
1967 The OSO-3 gamma-ray satellite discovers
gamma-ray emission from the plane of the Milky Way
1970 Launch of {\sevenit Uhuru}---first dedicated
X-ray satellite
1972 Launch of the {\sevenit Copernicus}
ultraviolet satellite
1974 {\sevenit Mariner 10} passes by and
photographs Mercury
1974 Launch of the {\sevenit Ariel V} X-ray
satellite
1975 {\sevenit Venera 9} returns the first
pictures of the surface of Venus
1976 {\sevenit Viking I} and {\sevenit Viking
II} land on Mars
1976 The {\sevenit Vela} and ANS X-ray satellites
discover X-ray bursts
1976 The OSO-8 X-ray satellite shows that
X-ray bursts have blackbody spectra
1977 Launch of the HEAO-1 X-ray satellite
1978 Launch of the {\sevenit International
Ultraviolet Explorer} satellite
1978 Launch of the {\sevenit Einstein} X-ray
satellite (HEAO-2)---first X-ray photographs of astronomical objects
1979 Launch of the {\sevenit Hakucho} X-ray
satellite (ASTRO-A)
1979 Launch of the {\sevenit Ariel VI} cosmic-ray
and X-ray satellite
1979 {\sevenit Voyager 1} and {\sevenit Voyager
2} send back images of Jupiter and its system
1980 {\sevenit Voyager 1} sends back images
of Saturn and its system
1980 Launch of the {\sevenit Solar Maximum
Mission} satellite
1981 {\sevenit Voyager 2} sends back images
of Saturn and its system
1983 Launch of the EXOSAT X-ray satellite
1983 Launch of the {\sevenit Tenma} X-ray
satellite (ASTRO-B)
1983 Launch of the IRAS satellite
1986 {\sevenit Voyager 2} sends back images
of Uranus and its system
1987 Launch of the {\sevenit Ginga} X-ray
satellite (ASTRO-C)
1989 {\sevenit Voyager 2} sends back images
of Neptune and its system
1989 Launch of the {\sevenit Granat} gamma-ray
and X-ray satellite
1989 Launch of the {\sevenit Hipparcos} satellite
1989 Launch of the COBE satellite
1990 Launch of the {\sevenit Hubble Space
Telescope}
1990 Launch of the ROSAT X-ray satellite---first
imaging X-ray sky survey
1990 First observations made with {\sevenit
Astro-1} (BBXRT, HUT, UIT, WUPPE)
1991 Launch of the {\sevenit Compton Gamma-Ray
Observatory} satellite
1993 Launch of the {\sevenit Asca} X-ray
satellite (ASTRO-D)
-320 Theophrastus begins the systematic study
of botany
1658 Jan Swammerdam observes red blood cells
under a microscope
1663 Robert Hooke sees cells in cork using
a microscope
1668 Francesco Redi disproves theories of
the spontaneous generation of maggots in putrefying matter
1676 Anton van Leeuwenhoek observes protozoa
and calls them ``animalcules''
1677 Anton van Leeuwenhoek observes spermatazoa
1683 Anton van Leeuwenhoek observes bacteria
1765 Lazzaro Spallanzani disproves many theories
of the spontaneous generation of cellular life
1771 Joseph Priestly discovers that plants
convert carbon dioxide into oxygen
1798 Thomas Malthus discusses human population
growth and food production in {\sevenit An Essay on the Principle of Population}
1801 Jean Lamarck begins the detailed study
of invertebrate taxonomy
1809 Jean Lamarck proposes an inheritance
of acquired characteristics theory of evolution
1817 Pierre-Joseph Pelletier and Joseph-Bienaim\'e
Caventou isolate chlorophyll
1828 Karl von Baer discovers the eggs of
mammals
1828 Friedrich W\"ohler synthesizes urea---first
synthesis of an organic compound
1836 Theodor Schwann discovers pepsin in
extracts from the stomach lining---first isolation of an animal enzyme
1837 Theodor Schwann shows that heating air
will prevent it from causing putrefaction
1838 Matthias Schleiden discovers that all
living plant tissue is composed of cells
1839 Theodor Schwann discovers that all living
animal tissue is composed of cells
1856 Louis Pasteur states that microorganisms
produce fermentation
1858 Charles R. Darwin and Alfred Wallace
independently propose natural selection theories of evolution
1858 Rudolf Virchow proposes that cells can
only arise from pre-existing cells
1862 Louis Pasteur convincingly disproves
the spontaneous generation of cellular life
1865 Gregor Mendel presents his experiments
on the crossbreeding of pea plants and postulates dominant and recessive
factors
1865 August Kekul\'e realizes that benzene
is composed of carbon and hydrogen atoms in a hexagonal ring
1869 Friedrich Miescher discovers nucleic
acids in the nuclei of cells
1874 Jacobus van't Hoff and Joseph-Achille
Le Bel advance a three-dimensional stereochemical representation of organic
molecules and
propose a tetrahedral
carbon atom
1876 Oskar Hertwig and Hermann Fol show that
fertilized eggs possess both male and female nuclei
1884 Emil Fischer begins his detailed analysis
of the compositions and structures of sugars
1898 Martinus Beijerinck uses filtering experiments
to show that tobacco mosaic disease is caused by something smaller than
a bacteria
which he names a
virus
1906 Mikhail Tsvett discovers the chromatography
technique for organic compound separation
1907 Ivan Pavlov demonstrates conditioned
responses with salivating dogs
1907 Emil Fischer artificially synthesizes
peptide amino acid chains and thereby shows that amino acids in proteins
are connected by
amino group-acid
group bonds
1911 Thomas Morgan proposes that Mendelian
factors are arranged in a line on chromosomes
1926 James Sumner shows that the urease enzyme
is a protein
1928 Otto Diels and Kurt Alder discover the
Diels-Alder cycloaddition reaction for forming ring molecules
1929 Phoebus Levene discovers the sugar deoxyribose
in nucleic acids
1929 Edward Doisy and Adolf Butenandt independently
discover estrone
1930 John Northrop shows that the pepsin
enzyme is a protein
1931 Adolf Butenandt discovers androsterone
1932 Hans Krebs discovers the urea cycle
1933 Tadeus Reichstein artificially synthesizes
vitamin C---first vitamin synthesis
1935 Rudolf Schoenheimer uses hydrogen-2
as a tracer to examine the fat storage system of rats
1935 Wendell Stanley crystallizes the tobacco
mosaic virus
1935 Konrad Lorenz describes the imprinting
behavior of young birds
1937 Theodosius Dobzhansky links evolution
and genetic mutation in {\sevenit Genetics and the Origin of Species}
1938 A living coelacanth is found off the
coast of southern Africa
1940 Donald Griffin and Robert Galambos announce
their discovery of sonar echolocation by bats
1942 Max Delbr\"uck and Salvador Luria demonstrate
that bacterial resistance to virus infection is caused by random mutation
and not
adaptive change
1944 Oswald Avery shows that DNA carries
the genetic code in pneumococci bacteria
1944 Robert Woodward and William von Eggers
Doering synthesize quinine
1948 Erwin Chargaff shows that in DNA the
number of guanine units equals the number of cytosine units and the number
of adenine units
equals the number
of thymine units
1951 Robert Woodward synthesizes cholesterol
and cortisone
1952 Alfred Hershey and Martha Chase use
radioactive tracers to show that DNA is the genetic material in bacteriophage
viruses
1952 Fred Sanger, Hans Tuppy, and Ted Thompson
complete their chromatographic analysis of the insulin amino acid sequence
1952 Rosalind Franklin uses X-ray diffraction
to study the structure of DNA and suggests that its sugar-phosphate backbone
is on
its outside
1953 James Watson and Francis Crick propose
a double helix structure for DNA
1953 Max Perutz and John Kendrew determine
the structure of hemoglobin using X-ray diffraction studies
1953 Stanley Miller shows that amino acids
can be formed when simulated lightning is passed through vessels containing
water, methane,
ammonia, and hydrogen
1955 Severo Ochoa discovers RNA polymerase
enzymes
1955 Arthur Kornberg discovers DNA polymerase
enzymes
1960 Juan Or\'o finds that concentrated solutions
of ammonium cyanide in water can produce the nucleotide organic base adenine
1960 Robert Woodward synthesizes chlorophyll
1967 John Gurden uses nuclear transplantation
to clone a clawed frog---first cloning of a vertebrate
1968 Fred Sanger uses radioactive phosphorous
as a tracer to chromatographically decipher a 120 base long RNA sequence
1970 Hamilton Smith and Daniel Nathans discover
DNA restriction enzymes
1970 Howard Temin and David Baltimore independently
discover reverse transcriptase enzymes
1972 Robert Woodward synthesizes vitamin
B-12
1972 Stephen Jay Gould and Niles Eldredge
propose punctuated equilibrium effects in evolution
1974 Manfred Eigen and Manfred Sumper show
that mixtures of nucleotide monomers and RNA-replicase will give rise to
RNA molecules which
replicate, mutate,
and evolve
1974 Leslie Orgel shows that RNA can replicate
without RNA-replicase and that zinc aids this replication
1977 John Corliss, Jack Dymond, Louis Gordon,
John Edmond, Richard von Herzen, Robert Ballard, Kenneth Green, David Williams,
Arnold
Bainbridge, Kathy
Crane, and Tjeerd van Andel discover chemosynthetically based animal communities
located around submarine
thermal springs
on the Gal\'apagos Rift
1977 Walter Gilbert and Allan Maxam present
a rapid gene sequencing technique which uses cloning, base destroying chemicals,
and
gel electrophoresis
1977 Fred Sanger and Alan Coulson present
a rapid gene sequencing technique which uses dideoxynucleotides and gel
electrophoresis
1978 Fred Sanger presents the 5,386 base
sequence for the virus $\phi$X174 --- first sequencing of an entire genome
1983 Kary Mullis invents the polymerase chain
reaction
1984 Alec Jeffreys devises a DNA fingerprinting
method
1985 Harry Kroto, J.R. Heath, S.C. O'Brien,
R.F. Curl, and Richard Smalley discover the unusual stability of the carbon-60
Buckminsterfullerine
molecule and deduce its structure
1990 Wolfgang Kr\"atschmer, Lowell Lamb,
Konstantinos Fostiropoulos, and Donald Huffman discover that Buckminsterfullerine
can be
separated from soot
because it is soluble in benzene
Medicine and Medical Technology
-420 Hippocrates begins the scientific study
of medicine by maintaining that diseases have natural causes
-280 Herophilus studies the nervous system
and distinguishes between sensory nerves and motor nerves
-250 Erasistratus studies the brain and distinguishes
between the cerebrum and cerebellum
50 Pedanius Dioscorides describes
the medical applications of plants in {\sevenit De Materia Medica}
180 Galen studies the connection between
paralysis and severance of the spinal cord
1242 Ibn an-Naf\=\i s suggests that the right
and left ventricles of the heart are separate and describes the lesser
circulation of blood
1249 Roger Bacon writes about convex lens
eyeglasses for treating farsightedness
1403 Venice implements a quarantine against
the Black Death
1451 Nicholas of Cusa invents concave lens
spectacles to treat nearsightedness
1543 Andreas Vesalius publishes {\sevenit
De Fabrica Corporis Humani} which corrects Greek medical errors and revolutionizes
medicine
1546 Gerolamo Fracastoro proposes that epidemic
diseases are caused by transferable seedlike entities
1553 Miguel Serveto describes the lesser
circulation of blood through the lungs
1559 Realdo Colombo describes the lesser
circulation of blood through the lungs in detail
1603 Girolamo Fabrici studies leg veins and
notices that they have valves which only allow blood to flow toward the
heart
1628 William Harvey explains the vein-artery
system and structure of the heart in {\sevenit De Motu Cordis et Sanguinis}
1701 Giacomo Pylarini gives the first smallpox
inoculations
1747 James Lind discovers that citrus fruits
prevent scurvy
1763 Claudius Aymand performs the first successful
appendectomy
1796 Edward Jenner develops a smallpox vaccination
method
1800 Humphry Davy announces the anaesthetic
properties of nitrous oxide
1816 Rene Laennec invents the stethoscope
1842 Crawford Long performs the first surgical
operation using anasthesia
1847 Ignaz Semmelweis studies and prevents
the transmission of puerperal fever
1870 Louis Pasteur and Robert Koch establish
the germ theory of disease
1881 Louis Pasteur develops an anthrax vaccine
1882 Louis Pasteur develops a rabies vaccine
1890 Emil von Behring discovers antitoxins
and uses them to develop tetanus and diptheria vaccines
1906 Frederick Hopkins suggests the existence
of vitamins and suggests that a lack of vitamins causes scurvy and rickets
1907 Paul Ehrlich develops a chemotheraputic
cure for sleeping sickness
1921 Edward Mellanby discovers vitamin D
and shows that its absence causes rickets
1928 Alexander Fleming discovers penicillin
1932 Gerhard Domagk develops a chemotheraputic
cure for streptococcus
1952 Jonas Salk develops the first polio
vaccine
-1700 Egyptian mathematicians employ primitive fractions
-530 Pythagoras studies propositional geometry
and vibrating lyre strings
-370 Eudoxus states the method of exhaustion
for area determination
-350 Aristotle discusses logical reasoning
in {\sevenit Organon}
-300 Euclid studies geometry as an axiomatic
system in {\sevenit Elements} and states the law of reflection in {\sevenit
Catoptrics}
-260 Archimedes computes $\pi$ to two decimal
places using inscribed and cirumscribed polygons and computes the area
under a parabolic segment
-200 Apollonius writes {\sevenit On Conic
Sections} and names the ellipse, parabola, and hyperbola
250 Diophantus writes {\sevenit Arithmetica},
the first systematic treatise on algebra
450 Tsu Ch'ung-Chih and Tsu K\^eng-Chih
compute $\pi$ to six decimal places
550 Hindu mathematicians give zero
a numeral representation in a positional notation system
1202 Leonardo Fibonacci demonstrates the
utility of Arabic numerals in his {\sevenit Book of the Abacus}
1424 Ghiy\=ath al-K\=ash\=\i\ computes $\pi$
to sixteen decimal places using inscribed and cirumscribed polygons
1520 Scipione Ferro develops a method for
solving cubic equations
1535 Niccol\`o Tartaglia develops a method
for solving cubic equations
1540 Lodovico Ferrari solves the quartic
equation
1596 Ludolf van Ceulen computes $\pi$ to
twenty decimal places using inscribed and cirumscribed polygons
1614 John Napier discusses Napierian logarithms
in {\sevenit Mirifici Logarithmorum Canonis Descriptio}
1617 Henry Briggs discusses decimal logarithms
in {\sevenit Logarithmorum Chilias Prima}
1619 Ren\'e Descartes discovers analytical
geometry
1629 Pierre de Fermat develops a rudimentary
differential calculus
1634 G.P. de Roberval shows that the area
under a cycloid is three times the area of its generating circle
1637 Pierre de Fermat claims to have proven
Fermat's Last Theorem in his copy of Diophantus' {\sevenit Arithmetica}
1654 Blaise Pascal and Pierre de Fermat create
the theory of probability
1655 John Wallis writes {\sevenit Arithmetica
Infinitorum}
1658 Christopher Wren shows that the length
of a cycloid is four times the diameter of its generating circle
1665 Isaac Newton invents his calculus
1668 Nicholas Mercator and William Brouncker
discover an infinite series for the logarithm while attempting to calculate
the area under a
hyperbolic segment
1671 James Gregory discovers the series expansion
for the inverse-tangent function
1673 Gottfried Leibniz invents his calculus
1675 Isaac Newton invents an algorithm for
the computation of functional roots
1691 Gottfried Leibniz discovers the technique
of separation of variables for ordinary differential equations
1693 Edmund Halley prepares the first mortality
tables statistically relating death rate to age
1696 Guillaume de L'H\^opital states his
rule for the examination of indeterminate forms
1706 John Machin develops a quickly converging
inverse-tangent series for $\pi$ and computes $\pi$ to 100 decimal places
1712 Brook Taylor develops Taylor series'
1722 Abraham De Moivre states De Moivre's
theorem
1724 Abraham De Moivre studies mortality
statistics and the foundation of the theory of annuities in {\sevenit Annuities
on Lives}
1730 James Stirling publishes {\sevenit The
Differential Method}
1733 Geralamo Saccheri studies what geometry
would be like if Euclid's fifth postulate were false
1734 Leonhard Euler introduces the integrating
factor technique for solving first order ordinary differential equations
1736 Leonhard Euler solves the Koenigsberg
bridge problem
1739 Leonhard Euler solves the general homogeneous
linear ordinary differential equation with constant coefficients
1742 Christian Goldbach conjectures that
every even number greater than two can be expressed as the sum of two primes
1744 Leonhard Euler shows the existence of
transcendental numbers
1748 Maria Agnesi discusses analysis in {\sevenit
Instituzioni Analitiche ad Uso della Gioventu Italiana}
1761 Thomas Bayes proves Bayes' theorem
1796 Karl Gauss presents a method for constructing
a heptadecagon using only a compass and straightedge and also shows that
only
polygons with certain
numbers of sides can be constructed
1797 Caspar Wessel associates vectors with
complex numbers and studies complex number operations in geometrical terms
1799 Karl Gauss proves that every polynomial
equation has a solution among the complex numbers
1806 Jean-Robert Argand associates vectors
with complex numbers and studies complex number operations in geometrical
terms
1807 Joseph Fourier first announces his discoveries
about the trigonometric decomposition of functions
1811 Karl Gauss discusses the meaning of
integrals with complex limits and briefly examines the dependence of such
integrals on
the chosen path
of integration
1815 Sim\'eon Poisson carries out integrations
along paths in the complex plane
1817 Bernard Bolzano presents Bolzano's theorem---a
continuous function which is negative at one point and positive at another
point must be zero
for at least one point in between
1824 Niels Abel partially proves that the
general quintic or higher equations do not have algebraic solutions
1822 Augustin-Louis Cauchy presents the Cauchy
integral theorem for integration around the boundary of a rectangle
1825 Augustin-Louis Cauchy presents the Cauchy
integral theorem for general integration paths---he assumes the function
being
integrated has a
continuous derivative
1825 Augustin-Louis Cauchy introduces the
theory of residues
1825 Peter Dirichlet and Adrien Legendre
prove Fermat's Last Theorem for n=5
1828 George Green proves Green's theorem
1829 Nikolai Lobachevski publishes his work
on hyperbolic non-Euclidean geometry
1832 \'Evariste Galois presents a general
condition for the solvability of algebraic equations
1832 Peter Dirichlet proves Fermat's Last
Theorem for n=14
1837 Pierre Wantsel proves that doubling
the cube and trisecting the angle are impossible with only a compass and
straightedge
1841 Karl Weierstrass discovers but does
not publish the Laurent expansion theorem
1843 Pierre-Alphonse Laurent discovers and
presents the Laurent expansion theorem
1843 William Hamilton discovers the calculus
of quaternions and deduces that they are non-commutative
1847 George Boole formalizes symbolic logic
in {\sevenit The Mathematical Analysis of Logic}
1849 George Stokes shows that solitary waves
can arise from a combination of periodic waves
1850 Alexandre Puiseux distinguishes between
poles and branch points and introduces the concept of essential singular
points
1850 George Stokes proves Stokes' theorem
1854 Bernhard Riemann introduces Riemannian
geometry
1854 Arthur Cayley shows that quaternions
can be used to represent rotations in four-dimensional space
1858 August M\"obius invents the M\"obius
strip
1870 Felix Klein constructs an analytic geometry
for Lobachevski's geometry thereby establishing its self-consistency and
the logical
independence of
Euclid's fifth postulate
1873 Charles Hermite proves that {\sevenit
e} is transcendental
1878 Charles Hermite solves the general quintic
equation by means of elliptic and modular functions
1873 Georg Frobenius presents his method
for finding series solutions to linear differential equations with regular
singular points
1882 Ferdinand Lindeman proves that $\pi$
is transcendental and that the circle cannot be squared with a compass
and straightedge
1882 Felix Klein invents the Klein bottle
1895 Diederik Korteweg and Gustav de Vries
derive the KdV equation to describe the development of long solitary water
waves in a
canal of rectangular
cross section
1896 Jacques Hadamard and Charles de La Vall\'ee-Poussin
independently prove the prime number theorem
1899 David Hilbert presents a set of self-consistent
geometric axioms in {\sevenit Foundations of Geometry}
1900 David Hilbert states his list of 23
problems which show where further mathematical work is needed
1901 \'Elie Cartan develops the exterior
derivative
1903 C. Runge presents a fast Fourier transform
algorithm
1908 Ernst Zermelo axiomatizes set theory
1912 L.E.J. Brouwer presents the Brouwer
fixed-point theorem
1914 Srinivasa Ramanujan publishes {\sevenit
Modular Equations and Approximations to $\pi$}
1928 John von Neumann begins devising the
principles of game theory and proves the minimax theorem
1930 Casimir Kuratowski shows that the three
cottage problem has no solution
1931 Kurt G\"odel shows that mathematical
systems are not fully self-contained
1933 Karol Borsuk and Stanislaw Ulam present
the Borsuk-Ulam antipodal-point theorem
1942 G.C. Danielson and Cornelius Lanczos
develop a fast Fourier transform algorithm
1943 Kenneth Levenberg proposes a method
for nonlinear least squares fitting
1948 John von Neumann mathematically studies
self-reproducing machines
1949 John von Neumann computes $\pi$ to 2,037
decimal places using ENIAC
1950 Stanislaw Ulam and John von Neumann
present cellular automata dynamical systems
1953 Nicholas Metropolis introduces the idea
of thermodynamic simulated annealing algorithms
1955 Enrico Fermi, John Pasta, and Stanislaw
Ulam numerically study a nonlinear spring model of heat conduction and
discover solitary wave
type behavior
1960 C.A.R. Hoare invents the quicksort algorithm
1960 Irving Reed and Gustave Solomon present
the Reed-Solomon error-correcting code
1961 Daniel Shanks and John Wrench compute
$\pi$ to 100,000 decimal places using an inverse-tangent identity and an
IBM-7090 computer
1962 Donald Marquardt proposes the Levenberg-Marquardt
nonlinear least squares fitting algorithm
1963 Martin Kruskal and Norman Zabusky analytically
study the Fermi-Pasta-Ulam heat conduction problem in the continuum limit
and find
that the KdV equation
governs this system
1965 Martin Kruskal and Norman Zabusky numerically
study colliding solitary waves in plasmas and find that they do not disperse
after collisions
1965 James Cooley and John Tukey present
an influential fast Fourier transform algorithm
1966 E.J. Putzer presents two methods for
computing the exponential of a matrix in terms of a polynomial in that
matrix
1976 Kenneth Appel and Wolfgang Haken use
a computer to solve the four-color problem
1983 Gerd Faltings proves the Mordell Conjecture
and thereby shows that there are only finitely many whole number solutions
for each
exponent of Fermat's
Last Theorem
1985 Louis de Branges proves the Bieberbach
Conjecture
1987 Yasumasa Kanada, David Bailey, Jonathan
Borwein, and Peter Borwein use iterative modular equation approximations
to elliptic
integrals and a
NEC SX-2 supercomputer to compute $\pi$ to 134 million decimal places
1993 Andrew Wiles proves part of the Taniyama-Shimura
Conjecture and thereby proves Fermat's Last Theorem
1620 Francis Bacon notices the jigsaw fit
of the opposite shores of the Atlantic Ocean
1701 Edmund Halley suggests using the salinity
and evaporation of the Mediterranean to determine the age of the Earth
1837 Louis Agassiz begins his glaciation
studies which eventually demonstrate that the Earth has had at least one
Ice Age
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
1903 George Darwin and John Joly claim that
radioactivity is partially responsible for the Earth's heat
1907 Bertram Boltwood proposes that the amount
of lead in uranium and thorium ores might be used to determine the Earth's
age and crudely
dates some rocks to have ages between 410--2200 million years
1912 Alfred Wegener proposes that all the
continents once formed a single landmass called Pangaea that broke apart
via
continental drift
1913 Albert Michelson measures tides in the
solid body of the Earth
1935 Charles Richter invents a logarithmic
scale to measure the intensity of earthquakes
1953 Maurice Ewing and Bruce Heezen discover
the Great Global Rift running along the Mid-Oceanic Ridge
1960 Harry Hess proposes that new sea floor
might be created at mid-ocean rifts and destroyed at deep sea trenches
1963 F.J. Vine and D.H. Matthews explain
the stripes of magnetized rocks with alternating magnetic polarities running
parallel to mid-ocean
ridges as due to sea floor spreading and the periodic geomagnetic field
reversals
Geography, Meteorology, Paleontology, Science Philosophy, and Science Publishing
25 Pomponius Mela formalizes the
climatic zone system
1569 Gerardus Mercator issues the first Mercator
projection map
1620 Francis Bacon analyzes the scientific
method in his {\sevenit Great Instauration of Learning}
1686 Edmund Halley presents a systematic
study of the trade winds and monsoons and identifies solar heating as the
cause of
atmospheric motions
1686 Edmund Halley establishes the relationship
between barometric pressure and height above sea level
1716 Edmund Halley suggests that aurorae
are caused by ``magnetic effluvia'' moving along the Earth's magnetic field
lines
1822 Gideon Mantell discovers the fossilized
skeleton of an iguanodon dinosaur
1869 Joseph Lockyer starts the scientific
journal {\sevenit Nature}
1909 Discovery of the Burgess Shale Cambrian
fossil site
1920 Andrew Douglass proposes dendrochronology
dating
1920 Milutin Milankovich proposes that long
term climatic cycles may be due to changes in the eccentricity of the Earth's
orbit and
changes in the Earth's
obliquity
1947 Willard Libby introduces carbon-14 dating
1949 Edward Murphy states his law
1974 Donald Johanson and Tom Gray discover
a 3.5 million-year-old female hominid fossil that is 40\% complete and
name it ``Lucy''
1980 Luis Alvarez, Walter Alvarez, Frank
Asaro, and Helen 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 K-T layer
1984 Hou Xianguang discovers the Chengjiang
Cambrian fossil site
Agriculture and Food Technology
-1800 Fermentation of dough, grain, and fruit juices
is discovered
600 The moldboard plow is invented
in eastern Europe
850 Coffee is invented in Arabia
1300 Arnau de Villanova develops alcohol
distillation
Clothing and Textiles Technology
1733 John Kay patents the flying shuttle loom
1764 James Hargreaves invents the spinning
jenny
1794 Eli Whitney patents the cotton gin
1801 Joseph-Marie Jacquard invents the Jacquard
punched card loom
1856 William Perkin invents the first synthetic
dye
1698 Thomas Savery builds a steam-powered
water pump for pumping water out of mines
1712 Thomas Newcomen builds a piston-and-cylinder
steam-powered water pump for pumping water out of mines
1769 James Watt patents his first improved
steam engine
1821 Michael Faraday builds an electricity-powered
motor
1876 Nikolaus Otto designs a four-stroke
internal-combustion engine
1888 Nikola Tesla patents the induction motor
-3500 Wheeled carts are invented
-3500 River boats are invented
-2000 Horses are tamed and used for transport
770 Iron horseshoes come into common
use
1492 Leonardo da Vinci describes a flying
machine
1662 Blaise Pascal invents a horse-drawn
public bus which has a regular route, schedule, and fare system
1740 Jacques de Vaucanson demonstrates his
clockwork powered carriage
1783 Joseph Montgolfier and \'Etienne Montgolfier
launch the first hot air balloons
1801 Richard Trevithick builds a prototype
steam powered railroad locomotive
1807 Isaac de Rivas makes a hydrogen gas
powered vehicle
1814 George Stephenson builds the first practical
steam powered railroad locomotive
1862 Jean Lenoir makes a gasoline-engine
automobile
1868 George Westinghouse invents the compressed
air locomotive brake
1900 Ferdinand von Zeppelin builds the first
successful dirigible
1903 Orville Wright and Wilbur Wright fly
the first motor-driven airplane
1908 Henry Ford develops the assembly line
method of automobile manufacturing
1947 First supersonic flight
1969 First manned mission to the Moon
1981 First flight of the space shuttle
1716 Edmund Halley builds a diving bell
1801 Robert Fulton builds the first submarine
1819 Augustus Siebe invents a diving suit
which receives air pumped down from the surface
1934 Charles Beebe dives to 3,028 feet using
a bathysphere
1943 Jacques-Yves Cousteau makes the first
dive with a compressed-air aqualung
-3500 The Sumerians develop cuneiform writing and
the Egyptians develop hieroglyphic writing
-1500 The Phoenicians develop an alphabet
-170 Parchment is discovered in Pergamum
105 Tsai Lun invents paper
350 The Chinese develop a method for
printing pages using symbols carved on a wooden block
1450 The Chinese develop wooden block movable
type printing
1454 Johannes Gutenberg finishes a printing
press with metal movable type
1793 Claude Chappe establishes the first
long-distance semaphore telegraph line
1831 Joseph Henry proposes and builds an
electric telegraph
1835 Samuel Morse develops the Morse code
1843 Samuel Morse builds the first long distance
electric telegraph line
1876 Alexander Graham Bell and Thomas Watson
exhibit an electric telephone
1877 Thomas Edison patents the phonograph
1889 Almon Strowger patents the direct dial
telephone
1901 Guglielmo Marconi transmits radio signals
from Cornwall to Newfoundland
1925 John Baird transmits the first television
signal
1958 Chester Carlson presents the first photocopier
suitable for office use
1966 Charles Kao realizes that silica-based
waveguides offer a practical way to transmit light via total internal reflection
1973 Akira Hasegawa and Fred Tappert propose
the use of solitary waves to carry information in optical fibers
1977 Donald Knuth begins work on \TeX
1980 Linn Mollenauer, Rogers Stollen, and
James Gordon demonstrate that solitary waves can be propagated through
optical fibers
1991 Anders Olsson transmits solitary waves
through an optical fiber with a data rate of 32 billion bits per second
1826 Joseph Ni\'epce takes the first permanent
photograph
1891 Thomas Edison patents the ``kinetoscopic
camera''
1973 Fairchild Semiconductor releases the
first large image forming CCD chip---100 rows and 100 columns
Calculator and Computer Technology
1617 John Napier discusses the Napier's bones
calculating method in {\sevenit Rabdologia}
1622 William Oughtred invents the slide rule
1623 Wilhelm Schickard builds his 6-digit
``Calculating Clock'' that can add and subtract
1645 Blaise Pascal completes his 5-digit
``Pascaline'' that can add
1930 Vannevar Bush builds a partly electronic
computer capable of solving differential equations
1946 Presper Eckert and John Mauchly announce
ENIAC, the first practical entirely electronic computer
1948 William Shockley, Walter Brattain, and
John Bardeen invent the transistor
1950 Alan Turing proposes the ``Turing test''
criterion for an intelligent machine
1951 Presper Eckert and John Mauchly finish
UNIVAC I, the first mass-produced electronic computer
1971 Texas Instruments releases the first
easily portable electronic calculator
1977 Apple Computer releases the Apple II
personal computer
-270 Ctesibius builds a popular water clock
-46 Julius Caesar and Sosigenes develop
a solar calendar with leap years
1502 Peter Henlein builds the first pocketwatch
1582 Pope Gregory XIII, Aloysius Lilius,
and Christopher Clavius introduce a Gregorian calendar with an improved
leap year system
1656 Christian Huygens builds the first accurate
pendulum clock
1737 John Harrison presents the first stable
nautical chronometer, thereby allowing for precise longitude determination
while at sea
1928 Joseph Horton and Warren Morrison build
the first quartz crystal oscillator clock
1946 Felix Bloch and Edward Purcell develop
nuclear magnetic resonance
1949 Harold Lyons develops an atomic clock
based on the quantum mechanical vibrations of the ammonia molecule
Temperature and Pressure Measurement Technology
1592 Galileo Galilei builds a crude thermometer
using the contraction of air to draw water up a tube
1643 Evangelista Torricelli invents the mercury
barometer
1714 Gabriel Fahrenheit invents the mercury
in glass thermometer
1864 Antoine Becquerel suggests an optical
pyrometer
1892 Henri-Louis Le Ch\^atelier builds the
first optical pyrometer
1590 Zacharias Janssen invents the microscope
1674 Anton van Leeuwenhoek invents the compound
microscope
1932 Ernst Ruska builds the first electron
microscope
1891 Z.F. Wroblewski condenses experimentally
useful quantities of liquid air
1892 James Dewar invents the vacuum-insulated,
silver-plated glass Dewar
1908 Heike Kammerlingh Onnes liquifies helium
1926 Robert Goddard launches the first liquid
fuel rocket
1944 Wernher von Braun and Walter Dornberger
launch the first V2 rocket
1958 Launch of the first ICBM
-4000 Copper metallurgy is invented and copper is
used for ornamentation
-3000 Bronze is used for weapons and armor
-1500 The Hittites develop crude iron metallurgy
-1200 Invention of steel when iron and charcoal
are combined properly
700 Porcelain is invented in China
1839 Charles Goodyear invents vulcanized
rubber
1909 Leo Baekeland presents the Bakelite
hard thermosetting plastic
1931 Julius Nieuwland develops the synthetic
rubber neoprene
1931 Wallace Carothers develops nylon
1953 Karl Ziegler discovers metallic catalysts
which greatly improve the strength of polyethylene polymers
-3000 Candles are invented
1815 Humphry Davy invents the miner's safety
lamp
1879 Thomas Edison patents the carbon-thread
incandescent lamp
-7000 Pottery is invented
-700 Invention of aqueducts
-640 Invention of coins
-400 Catapults are invented in Syracuse
-150 Hipparchus invents the astrolabe
-100 Glass-blowing is discovered in Syria
700 Windmills are invented in Persia
1050 Crossbows are invented in France
1249 Roger Bacon states formulas for gunpowder
1346 Cannon come into wide use
1480 Martin Behaim introduces the nautical
astrolabe
1480 Leonardo da Vinci describes a workable
parachute
1645 Otto von Guericke builds the first vacuum
pump
1731 John Hadley invents the sextant
1800 Alessandro Volta announces his invention
of the electric battery
1823 William Sturgeon invents the electromagnet
1840 Justus von Liebig invents artificial
fertilizer
1867 Alfred Nobel patents dynamite
1880 John Milne invents the seismograph
1885 William Stanley invents the alternating
current transformer
1903 Konstantin Tsiolkovsky begins a series
of papers discussing the use of rocketry to reach outer space, space suits,
and
colonization of
the solar system
1917 Paul Langevin develops a sonar echolocation
system
1925 Theodor Svedberg develops the ultra-centrifuge,
thereby revolutionizing the determination of molecular weights
1935 Robert Watson-Watt devises a microwave
radar
1945 First nuclear fission bomb exploded
at the Trinity test site, about sixty miles northwest of Alamogordo, New
Mexico
1952 First thermonuclear fusion bomb exploded
1952 Wernher von Braun discusses the technical
details of a manned exploration of Mars in {\sevenit The Mars Project}
1953 Charles Townes makes the first maser
1954 Construction of the first nuclear power
reactor
1960 Theodore Maiman makes the first laser
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