Coming of Age in the Milky Way (68 page)

Noteworthy Events
: Kurt Gödel’s second incompleteness theorem indicates that the consistency of any system, including scientific systems, cannot be proved internally—i.e., that mathematics, and science are inherently open-ended.

Time
: 1932

Noteworthy Events
: James Chadwick discovers the neutron.

Noteworthy Events
: Carl Anderson, without knowing of Dirac’s 1931 paper postulating its existence, discovers the positron.

Noteworthy Events
: Karl Jansky finds that the Milky Way emits radio waves, opening door on the science of radio astronomy.

Time
: 1935

Noteworthy Events
: Hideki Yukawa predicts existence of the meson.

Time
: 1939

Noteworthy Events
: Niels Bohr and John Archibald Wheeler develop the theory of nuclear fission.

Noteworthy Events
: Hans Bethe and Carl Friedrich von Weizsäcker independently arrive at theory of the carbon and proton-proton reactions in stars.

Time
: 1940

Noteworthy Events
: Grote Reber constructs a backyard radio telescope, makes the first radio map of the Milky Way.

Time
: 1943

Noteworthy Events
: Carl Seyfert identifies Seyfert galaxies, the first of a larger class of galaxies found to have bright nuclei that emit abnormal amounts of energy.

Time
:
1944

Noteworthy Events
: Walter Baade resolves the central region of the Andromeda galaxy into stars, establishing a fundamental distinction between the older, redder stars characteristic of the centers of spiral galaxies, and the younger, bluer stars found in their spiral arms.

Time
: 1945

Noteworthy Events
: Hendrik van de Hülst predicts that clouds of interstellar hydrogen emit radio energy at the 21-centimeter wavelength.

Time
: 1946

Noteworthy Events
: James Hey, S. J. Parsons, and J. W. Phillips identify a powerful radio source in Cygnus, initiating research that leads to finding galaxies that emit enormous amounts of energy at radio wavelengths.

Time
: 1948

Noteworthy Events
: Dedication of the 200-inch telescope on Palomar Mountain.

Noteworthy Events
: Ralph Alpher and George Gamow theorize about the physics of the early universe; Alpher and Robert Herman, correcting Gamow’s arithmetic, then predict that the big bang should have produced a cosmic microwave background radiation.

Time
: 1948–1949

Noteworthy Events
: “Renormalization” of quantum electrodynamics removes unwanted infinities from the equations.

Time
: 1948–1950

Noteworthy Events
: Willard Frank Libby develops technique of radiocarbon dating.

Time
: 1949

Noteworthy Events
: John Bolton, Gordon Stanley, and O. B. Slee use radio interferometry to identify three radio sources with visible objects; two of them are galaxies, suggesting that what had been thought to be radio “stars” are actually objects lying much farther away in space.

Time
: 1951

Noteworthy Events
: Harold Ewen and Edward Purcell, closely followed by C. Alex Muller and Jan Oort, detect 21-centimeter radio radiation emitted by interstellar clouds.

Time
: 1952

Noteworthy Events
: Baade clears up serious discrepancies in the cosmic distance scale when he finds that the Cepheid variable stars used in measuring intergalactic distances actually come in two varieties, with different magnitude-periodicity relationships,

Time
: 1953

Noteworthy Events
: Murray Gell-Mann proposes a new quantum number called strangeness, notes that it is conserved in strong interactions.

Time
: 1954

Noteworthy Events
: Walter Baade and Rudolph Minkowski identify the radio source Cygnus A with a distant galaxy.

Noteworthy Events
:
Chen Ning Yang and Robert Mills develop a gauge symmetrical field theory, a major step toward viewing the universe in terms of underlying symmetries that were broken in early cosmic evolution.

Time
: 1956

Noteworthy Events
: Yang and Tsung Dao Lee theorize that parity is not conserved in weak interactions—i.e., that the weak force does not function symmetrically. Experiments conducted by Chien-Shiung Wu and collaborators the same year confirm their prediction.

Time
: 1957

Noteworthy Events
: Julian Schwinger proposes that the electromagnetic and weak forces are but aspects of a single variety of interaction.

Time
: 1958

Noteworthy Events
: Oort and colleagues use radio telescopes to map the spiral arms of the Milky Way galaxy.

Time
: 1960

Noteworthy Events
: Allan Sandage and Thomas Matthews discover quasars.

Time
: 1961

Noteworthy Events
: Gell-Mann and Yuval Ne’eman independently arrive at the “eightfold way” scheme of classifying subatomic particles that react to the strong nuclear force.

Time
: 1963

Noteworthy Events
: Maarten Schmidt finds redshift in the spectral lines of a quasar, indicating that quasars are the most distant class of objects in the universe.

Time
: 1964

Noteworthy Events
: Murray Gell-Mann and George Zweig independently propose that protons, neutrons, and other hadrons are composed of still smaller particles, which Gell-Mann dubs “quarks.”

Noteworthy Events
: The omega-minus particle is detected at Brookhaven National Laboratory, confirming a prediction of the Gell-Mann-Ne’eman “eightfold way.”

Time
: 1965

Noteworthy Events
: Arno Penzias and Robert Wilson discover the cosmic microwave background radiation, light left over from the big bang.

Time
: 1967

Noteworthy Events
: Chia Lin and Frank Shu show that the spiral arms of galaxies may be created by density waves propagating across the galactic disk.

Noteworthy Events
: Jocelyn Bell and Antony Hewish discover pulsars, leading to verification of the existence of extremely dense “neutron stars.”

Time
: 1968

Noteworthy Events
: Experiments at the Stanford Linear Accelerator Center support the theory that hadrons are made of quarks.

Time
: 1981

Noteworthy Events
: Alan Guth postulates that the early universe went through an “inflationary” period of exponential expansion.

Time
:
1983

Noteworthy Events
: Electroweak unified theory verified in collider experiments at CERN. Attempts accelerate to arrive at a unified theory of all four forces.

Time
: 1987

Noteworthy Events
: Proton-decay experiments in the United States and Japan detect neutrinos broadcast by a supernova in the Large Magellanic Cloud, ushering in the new science of observational neutrino astronomy.

Time
: 1988

Noteworthy Events
: Quasars are detected near the outposts of the observable universe; their redshifts indicate that their light has been traveling through space for some seventeen billion years.

Time
: 1990

Noteworthy Events
: COBE satellite measures cosmic microwave background radiation; confirms that it displays a black-body spectrum as predicted by the hot big-bang model.

Time
: 1992

Noteworthy Events
: COBE satellite data show anisotropies—lumps—in the cosmic microwave background, supporting big-bang prediction that such lumps were the seeds of galaxies and other large-scale cosmic structures.

Time
: 1998

Noteworthy Events
: Astronomers studying Supernovae find evidence that the expansion of the universe is accelerating, rather than slowing down as had been presumed.

Time
: 2000

Noteworthy Events
: Measurements of cosmic microwave background anisotropies indicate that cosmic spacetime is flat or nearly so, as predicted by inflationary versions of big-bang theory.

Time
: 2003

Noteworthy Events
: WMAP satellite makes high-precision map of cosmic microwave background, supporting earlier CMB studies and yielding an age for the universe of 13.7 billion years, to a quoted accuracy of one percent.

1.
Carlyle,
On History
, in Pais, 1986, p. 129.

1.
Copernicus,
On the Revolutions
, Wallis translation, p. 510.

2.
Hesiod,
Works and Days
, Wender translation, p. 78.

3.
In Williamson, 1984, p. 297.

4.
Ibid., p. 210.

5.
In Morison, 1963, p. 362.

6.
In Wycherley, 1978, p. 222.

7.
Aristotle,
On Youth
, 2, 14, in Barnes, 1984.

8.
In Duhem, 1969, p. 19.

9.
Ibid., p. 17.

10.
Plato,
Phaedrus
230a, Hackford translation, in Hamilton and Cairns edition, 1969.

1.
Archimedes, “The Sand Reckoner,” in
The Works of Archimedes
, Heath translation, 1952, p. 520.

2.
Ibid.

3.
Ibid.

4.
Plutarch,
Lives
, Vol. II, p. 282.

5.
In Pappus,
Collectio
, Book VIII, Prop. 10, Sect. XI.

6.
Plutarch,
Lives
, Vol. II, p. 283.

7.
Ibid., p. 286.

8.
Euclid, Heath translation, p. 3.

9.
The Gospel According to Saint John,
Chapter 18
.

10.
In Adams, 1938, pp. 52–53.

11.
In Alic, 1986.

12.
In Nasr, 1964, p. 182.

13.
Boethius, Watts translation, pp. 46–47.

14.
Ibid., p. 57.

15.
Ibid., p. 73.

1.
Virgil,
Aeneid
, Bk. 3, 512–27, T.F. translation.

2.
In Morison, 1963.

3.
In Garnet, 1970, p. 49.

4.
Su, Watson translation, 1965.

5.
In Bell, 1974, p. 46.

6.
In Parry, 1963, p. 247.

7.
In Beazley, p. 213.

8.
In Needham, 1954–1984, Vol. 2, p. 525.

9.
Ibid., Vol. 4,
Part 3
, p. 514.

10.
Encyclopaedia Britannica, 3rd ed., Vol. 4, p. 937.

11.
In Newby, 1975, p. 67.

12.
In Columbus, Ferdinand, 1979, p. 10.