100 Greatest Discoveries

Ten milestones that have helped to tell life's story: Walter Alvarez's asteroid theory of dinosaur extinction, the first identification of dinosaur fossils Stanley Miller's simulation of the early atmosphere, Robert Ballard's discovery of hydrothermal vent ecosystems, Charles Walcott's analysis of the Burgess Shale, the Linnaean classification system, Darwin's theory of natural selection, Donald Johanson's Lucy, Mary Leakey's Laetoli footprints, and Michel Brunet's Toumai skull.

Twelve landmark steps to understanding the Earth's structure: Richard Oldham's theory of a liquid core, Inge Lehmann's conclusion that the core is solid iron, Alfred Wegener's premise of continental drift, Harry Hess's findings on seafloor spreading, plate tectonics, Leon Teisserenc de Bort's discovery of atmospheric layers, the theory of global warming, Victor Hess's studies of cosmic rays, Bernard Brunhes's assertion of magnetic field reversal, Charles Lyell's ideas on geological change, Bertram Boltwood's formulas for radiometric dating, and Milutin Milankovitch's ideas on periodic ice ages.

Thirteen discoveries that help explain why matter and energy behave as they do: Galileo's law of falling bodies, Isaac Newton's conclusions of universal gravity, Newton's laws of motion, the second law of thermodynamics, experiments in electromagnetism, Albert Einstein's Special Theory of Relativity and his equation E=mc2, Quantum theory, calculations on the nature of light, James Chadwick's discovery of the neutron, the development of superconductivity, Murray Gell-Mann's proposal of quarks, and the discovery of the strong and weak nuclear forces.

Thirteen achievements in medicine: Andreas Vesalius's anatomical charts, William Harvey's breakthrough on blood circulation, Karl Landsteiner's identification of blood groups, the development of anesthesia, Wilhelm Roentgen's discovery of X-rays, Louis Pasteur's establishment of bacteriology, Frederick Hopkins's recognition of the importance of vitamins, the discovery and isolation of penicillin, the development of sulfa drugs, Edward Jenner's invention of vaccine, and the discoveries of insulin, oncogenes and the human immunodeficiency virus (HIV).

Thirteen crucial benchmarks in the history of what may be the oldest science: Ancient awareness that the planets move, Copernican cosmology, Johannes Kepler's laws of planetary motion, Galileo's discovery of Jupiter's moons, Edmund Halley's comet prediction, William and Carolyn Herschel's galactic mapping, Einstein's General Theory of Relativity, Edwin Hubble's proof that the universe is expanding, Karl Jansky's discovery of galactic radio waves, Arno Penzias and Robert Wilson's detection of the cosmic microwave background, observations of gamma ray bursts, the discovery of extrasolar planets, and the "big rip" theory.

Thirteen building blocks in a science that may be the foundation of the modern world: Joseph Priestly and Antoine Lavoisier's discovery of oxygen, John Dalton's atomic theory, Avogadro's Law, Friedrich Woehler's synthesis of urea, Friedrich Kekule's studies of molecular structure, Dmitry Mendeleyev's Periodic Table, Humphry Davy's electrolysis, J. J. Thomson's discovery of the electron, Niels Bohr's model of atomic structure, Gustav Kirchhoff and Robert Bunson's electromagnetic spectroscopy, Marie Curie's isolation of radioactive materials, John Wesley Hyatt and Leo Baekeland's invention of plastics, and the discovery of fullerenes.