Sunday, January 15, 2012

Astronomy of the 20th Century


Astronomy of the 20th Century
The 20th century brought many new developments to the study of space. Huge telescopes, such as the 10-m (400-in) Keck telescopes, came into use. Astronomers began to use the Hubble Space Telescope and other space-based observatories. They also began to measure and record radiation that is not visible to the human eye.
Period
Year
Event

1900-1919
1905
Einstein states the special theory of relativity.
1908
Hertzsprung classifies stars by their brightness: dwarfs and giants.
1912
The period-luminosity correlation of Cepheids is calculated by H. Leavitt.
1916
Einstein publishes the general theory of relativity.
1917
The mirror of the Mount Wilson telescope (2.5 m) is put into use.
1920-1939
1923
Hubble discovers that spiral nebulas are galaxies outside the Milky Way.
1929
Hubble suggests that the universe is expanding.
1930
Tombaugh discovers Pluto.
1931
The first radio waves in space are observed by Jansky.
1937
With a radio telescope, Reber observes radio radiation from the Milky Way.
1938
Hans Bethe states the theory of nuclear energy, source of star radiation.
1940-1949
1942
Discovery of radio emissions from the Sun by the team of Hey.
1946
Identification of the most powerful radio source in the sky (Cygnus A) by Hey, Phillips, and Parsons.
1948
Use of the 5-m telescope on Mount Palomar (California) begins.
Cosmological theory of the stationary universe presented by Bond and Gold.
Big bang theory and the origin of elements is developed by Alpher and Gamow.
1950-1959
1952
The scale of the distance to the galaxies is doubled by Baade.
1957
Launch of the first Sputnik: The era of space conquest opens.
1959
The Soviet probe Luna 3 takes the first pictures of the hidden side of the Moon.
1960-1969
1961
Gagarin takes the first piloted space flight.
1962
The first planetary mission succeeds: The United States probe Mariner 2 flies past Venus.
1963
The first quasar is discovered by Schmidt at Mount Palomar.
1965
Discovery of radio radiation in deep space at 3 K by Penzias and Wilson.
1967
Bell Burnell discovers pulsars at Cambridge (Great Britain).
V. Komarov (USSR) is the first human victim of a space flight.
1969
The mission Apollo 11 (Armstrong and Aldrin) puts the first human on the Moon.
1970-1974
1971-1972
The U.S. probe Mariner 9 orbits Mars and gathers the first images.
1973
First flight past Jupiter by Pioneer 10.
A telescope 4 m in diameter is put into service at Kitt Peak (Arizona).
1974
The probe Mariner 10 registers the first surface details of Mercury and of the
atmosphere of Venus.
1975-1979
1975
Soviet space probes Verena 9 and 10 take the first photographs of the Sun from Venus.
U.S.-Soviet space docking of Apollo-Soyuz.
1976
U.S. probes Viking 1 and 2 land on Mars (first measurements of the atmosphere and surface).
1977
Kowal discovers the asteroid Chiron within the solar system.
Discovery of Uranus's rings.
1978
Christy discovers Charon, Pluto's satellite.
1979
Launch of two U.S. probes, Voyager 1 and 2, which fly past Jupiter.
Pioneer 11 achieves the first flyby of Saturn.
1980-1984
1980
Long baseline interferometer is put into service in New Mexico.
1980-1981
First detailed study of Saturn and its rings by U.S. probes Voyager 1 and 2.
1981
First flight of the U.S. space shuttle.
Second flyby of Saturn by Voyager 2.
1983
First infrared scanning of space, by the Infrared Astronomy Satellite (IRAS), starts.
1984
First in-space repair of an artificial satellite.
1985-1989
1985-1986
Observation of Halley's Comet by different Soviet, European, and Japanese probes.
1986
Flyby of Uranus by Voyager 2.
U.S. space shuttle Challenger explodes in flight.
1987
Supernova 1987A appears in the Large Magellanic Cloud.
1988
Record human stay in space: V. Titov and M. Manarov return to Earth after a
one-year-long space flight.
1989
Voyager 2 flies by Neptune.
Discovery of dense 'walls' and empty spaces in the spatial distribution of galaxies, by Geller and Uchra.
Two U.S. probes are launched: Magellan towards Venus, and Galileo towards Jupiter.
1990-1999
1990
Launch of the Hubble Space Telescope; defectiveness of mirror is discovered.
First radar cartography of Venus made by Magellan.
1992
Two signals almost as old as the universe itself are registered by the satellite COBE.
Service of the telescope Keck, 10 m in diameter, begins.
1993
In-space repair of the Hubble Space Telescope.
1994
Fragmented comet Shoemaker-Levy collides with Jupiter.
1995
European Solar and Heliophysical Observatory (SOHO) launched to study the Sun.
1996
Mars Pathfinder and Sojourner rover explore the surface of Mars.
1998
Voyager 1 becomes most distant human-made object from Earth.
Construction of the International Space Station begins.
1999
Mars Global Surveyor begins systematic mapping of Mars.

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