Timeline of knowledge about galaxies, clusters of galaxies, and large-scale structure |
Timeline of galaxies, clusters of galaxies, and large-scale structure of the cosmos
- 964 - Al Sufi, a Persian astronomer makes the first preserved recording of
the Large Magellanic Cloud.
- 1521 - Ferdinand
Magellan observes the Magellanic Clouds during his
circumnavigating expedition,
- 1610 - Galileo Galilei uses
a telescope to determine that the bright band on the sky, the "Milky Way", is composed of many faint stars,
- 1750 - Thomas Wright discusses galaxies and the shape of the
Milky Way,
- 1755 - Drawing on Wright's work, Immanuel Kant conjectures that the galaxy is a rotating disk of stars held together by gravity, and that the nebulae are separate such
galaxies,
- 1845 - Lord Rosse discovers a nebula with a distinct spiral shape
- 1918 - Harlow Shapley
demonstrates that globular clusters are arranged in an spheroid or
halo whose center is not the Earth, decides, correctly, that its center is the center of
the galaxy,
- 1920 - Harlow Shapley 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,
- 1930 - Robert Trumpler uses
open cluster observations to quantify the absorption of light by interstellar dust in the galactic plane; this
absorption had plagued earlier models of the Milky Way,
- 1932 - Karl Guthe
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 Keenan
Seyfert identifies six spiral galaxies with unusually broad emission
lines, named Seyfert galaxies,
- 1949 - J.G. Bolton, G.J. Stanley, and O.B. Slee identify NGC 4486 (M87) and NGC 5128 as extragalactic radio sources,
- 1953 - Gerard 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 quasistellar object,
- 1962 - Cyril Hazard, M.B. Mackey, and A.J. Shimmins use lunar occultations to determine
a precise position for the quasar 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 - R. Brent Tully and
Richard Fisher publish 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 Boötes 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 in the
direction of the Hydra and Centaurus,
- 1989 - Margaret Geller and John Huchra discover the "Great
Wall", a sheet of galaxies more than 500 million light years long and 200 million wide, but only 15 million light years
thick,
- 1990 - Michael Rowan-Robinson and Tom Broadhurst discover that the IRAS galaxy F10214+4724 is the brightest known object in the
Universe.
- 2004 - The European Southern Observatory discovers Abell 1835 IR1916, the most distant galaxy yet seen by humans.
See also: Large-scale
structure of the cosmos
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