Coming of Age in the Milky Way (66 page)

Time
: 11 million years

Noteworthy Events
: Grazing animals proliferate.

Time
: 5 million years

Noteworthy Events
: Apeman diverges from chimpanzee family.

Time
: 3.7 million years

Noteworthy Events
: Apemen walk upright.

Time
: 3.5 million years

Noteworthy Events
: Onset of latest series of ice ages.

Time
: 1.8–1.7 million years

Noteworthy Events
:
Homo erectas
, “first true man,” in China.

Time
: 600,000 years

Noteworthy Events
:
Homo sapiens
emerges.

Time
: 360,000 years

Noteworthy Events
: Controlled use of fire common among genus
Homo
.

Time
: 150,000 years

Noteworthy Events
: Woolly mammoth roam.

Time
: 100,000 years

Noteworthy Events
: Stars take on the forms of the recognizable modern constellations.

Time
: 40,000 years

Noteworthy Events
: Invention of complex language; modern humans flourish.

Time
: 35,000 years

Noteworthy Events
: Neanderthal man disappears. First musical instruments are crafted.

Time
: 20,000–15,000 years

Noteworthy Events
: Agriculture invented.

Time
: 19,000 years

Noteworthy Events
: Peopling of the Americas begins.

Time
: 18,000 years

Noteworthy Events
: Animals are herded by humans.

Time
: 14,000 years

Noteworthy Events
: Invention of fishhooks.

Time
: 13,000 years

Noteworthy Events
: Development of ceramic pottery.

Time
: 10,000 years

Noteworthy Events
: Cultivation of wheat, rice begins.

Time
: 6,700 years

Noteworthy Events
: Early Babylonian calendar in use.

Time
: 6,200 years

Noteworthy Events
: Refined solar calendar employed.

Time
: 6,500 years

Noteworthy Events
: Copper is smelted.

Time
: 5,600 years

Noteworthy Events
: First taxes.

Time
:
5,500 years
BP (= 3,500 BC)

Noteworthy Events
: Development of writing.

Time
: 3,600–3,400 BC

Noteworthy Events
: Cotton cultivated in Peru, Mexico.

Time
: 2,500 years

Noteworthy Events
: Stonehenge built.

Time
: 2,200 years

Noteworthy Events
: Systematic astronomy in Egypt, Babylonia, India, China.

Time
: 1,500 years

Noteworthy Events
: Sundial invented, in Egypt.

Time
: 1,000 years

Noteworthy Events
: Homer declaims the
Odyssey
.

Time
: 800 years

Noteworthy Events
: Olmec culture in Mexico.

Time
: 700 years

Noteworthy Events
: Hesiod,
Works and Days
.

Time
: 650 years

Noteworthy Events
: Mayan culture in Guatemala.

Time
: 600 years

Noteworthy Events
: Lao-tzu, Confucius, Buddha, Zoroaster; Old Testament in Hebrew.

Time
: 540 years

Noteworthy Events
: Pythagoras teaches that “all is number” and that nature is harmonious.

Time
: 450 years

Noteworthy Events
: Leucippus and Democritus propose that matter is made of indivisible entities, the atoms. Paradoxes of Zeno raise doubts about the concept of the infinitesimal.

Time
: 400 years

Noteworthy Events
: Plato teaches that the material world is but a shadow of a geometrically perfect reality. Aristotle, Eudoxus, theorize that universe is composed of crystalline spheres centered on Earth.

Time
: 300 years

Noteworthy Events
: Euclid’s geometry marries mathematical perfection to the world of experience.

Time
: 260 years

Noteworthy Events
: Aristarchus of Samos hypothesizes that the earth orbits the sun in a gigantic universe.

Time
: 100 years

Noteworthy Events
: Chinese seafarers reach the east coast of India.

Time
: 60 BC

Noteworthy Events
: Lucretius writes
De Rerum Natura (On the Nature of Things)
, espousing Epicurean cosmology.

Time
: AD 100

Noteworthy Events
: Claudius Ptolemy constructs a complex geocentric cosmological model that “saves the appearances”—i.e., makes reasonably accurate predictions at the expense of claims to represent physical reality.

Time
: 325

Noteworthy Events
: Eusebius, chairman of the Council of Nicaea convened by the emperor Constantine, estimates that the world was created 3,184 years prior to the birth of Abraham.

Time
:
400

Noteworthy Events
: Middle or Dark Ages begin; science dormant in the West.

Time
: 455

Noteworthy Events
: Vandals sack Rome.

Time
: 963

Noteworthy Events
: Al Sufi, in his
Book of the Fixed Stars
, mentions nebulae.

Time
: 1001

Noteworthy Events
: Leif Ericsson reaches New England.

Time
: 1276–1292

Noteworthy Events
: Marco Polo in Hangchow.

Time
: 1400

Noteworthy Events
: Renaissance of learning commences in Europe.

Time
: 1492

Noteworthy Events
: Columbus (re)discovers America.

Time
: 1521

Noteworthy Events
: Cortez takes Mexico.

Time
: 1522

Noteworthy Events
: Survivors of Magellan’s final expedition complete circumnavigation of the globe.

Time
: 1523

Noteworthy Events
: Pizarro takes Peru.

Time
: 1543

Noteworthy Events
: Copernicus’s
On the Revolutions
published.

Time
: 1572

Noteworthy Events
: Tycho sees a nova (or “new star”) in the sky, evidence against Aristotle’s theory that the realm of the stars is unchanging and therefore unlike that of the earth.

Time
: 1576

Noteworthy Events
: Thomas Digges in England publishes a defense of the Copernican cosmology in which he portrays the stars as distributed throughout infinite space.

Time
: 1604

Noteworthy Events
: Galileo proposes that bodies fall with a uniformly accelerated motion, thus enunciating the first of the laws of classical dynamics.

Noteworthy Events
: Kepler and Galileo observe a supernova.

Time
: 1609

Noteworthy Events
: Galileo first observes the night sky through a telescope.

Noteworthy Events
: Kepler demonstrates that the orbits of the planets are elliptical.

Time
: 1611

Noteworthy Events
: Edition of the King James Bible published containing an estimate by James Ussher, bishop of Armagh, that “the beginning of time … fell on the beginning of the night which preceded the 23 rd day of October, in the year … 4004
B.C.
”

Time
: 1616

Noteworthy Events
: Roman Catholic Church bans all books that maintain that the earth moves.

Time
: 1639

Noteworthy Events
: Transit of Venus observed by two English amateur astronomers.

Time
: 1662

Noteworthy Events
: Royal Society chartered in London.

Time
: 1665–1666

Noteworthy Events
: Isaac Newton, age twenty-three, home from college, realizes
that gravitational force obeying an inverse-square law would account alike for falling bodies on earth and the motion of the moon in its orbit.

Time
: 1666

Noteworthy Events
: Newton observes spectrum produced by sunlight when shown through a prism.

Time
: 1672

Noteworthy Events
: Opposition of Mars widely observed, by Richer at Cayenne and Cassini in Paris among others, leading to estimates of the distance from the earth to the sun of some eighty-one to eighty-seven million miles—90 percent of the correct value.

Time
: 1675

Noteworthy Events
: Olaus Römer determines, from studying the satellites of Jupiter, that light has a finite velocity.

Time
: 1684

Noteworthy Events
: Edmond Halley visits Isaac Newton at Trinity College, resurrects line of research that leads Newton to write the
Principia
.

Time
: 1686

Noteworthy Events
: Bernard de Fontenelle’s
Entretiens sur la Plurality des Mondes
popularizes the idea that the universe contains many inhabited worlds.

Time
: 1687

Noteworthy Events
: Newton’s
Principia
published.

Time
: 1716

Noteworthy Events
: Halley urges that future transit of Venus may be observed and timed in order to triangulate interplanetary distances.

Time
: 1718

Noteworthy Events
: Halley finds that the bright stars Sirius, Aldebaran, Betelgeuse, and Arcturus have changed their position in the sky since Ptolemy’s
Almagest
was compiled—first evidence of the “proper motion” of stars.

Time
: 1719

Noteworthy Events
: John Strachey in England publishes notes on strata in the coal-rich district of Somerset, an early step in the establishment of geological science.

Time
: 1728

Noteworthy Events
: James Bradley finds aberration in starlight produced by the motion of the earth.

Time
: 1750–1784

Noteworthy Events
: French amateur astronomer Charles Messier catalogs scores of indistinct celestial objects that might be mistaken for comets; many will prove to be star clusters and interstellar gas clouds, others external galaxies.

Time
: 1755

Noteworthy Events
: Kant proposes that spiral nebulae are galaxies of stars.

Time
: 1761, 1769

Noteworthy Events
: Transits of Venus observed by widely scattered scientific expeditions, permitting new determinations of the distance from the earth to the sun—the “astronomical unit.”

Time
:
1765

Noteworthy Events
: John Harrison is acknowledged by the English Board of Longitude to have developed the marine chronometer, making possible accurate timekeeping and the determination of longitude at sea.

Time
: 1766

Noteworthy Events
: Henry Cavendish identifies hydrogen, the most abundant element in the universe.

Time
: 1781

Noteworthy Events
: William Herschel discovers the planet Uranus.

Time
: 1783

Noteworthy Events
: Herschel derives the general direction of the solar system’s motion through space, by studying the proper motion of thirteen bright stars.

Time
: 1793

Noteworthy Events
: William Smith, a canal surveyor and consulting engineer excavating the Somersetshire Coal Canal, finds evidence for a consistent sequence of geological strata throughout England.

Time
: 1795

Noteworthy Events
: James Hutton’s
Theory of the Earth
advances a uniformitarian hypothesis of geological change having taken place in the course of a lengthy past.

Time
: 1800

Noteworthy Events
: William Herschel detects infrared light.

Time
: 1801

Noteworthy Events
: Johann Ritter detects ultraviolet light.

Noteworthy Events
: Georges Cuvier identifies twenty-three species of extinct animals in the fossil record, confounding the doctrine that all species were created simultaneously and are imperishable.