History of Cosmology Timeline

From rudimentary instruments and mathematical tools to outstanding predictive success

Citation Information

Allan, Leslie 2015. History of Cosmology Timeline, URL = <>.

From Andreas Cellarius Harmonia Macrocosmica, 1660/61. Chart showing signs of the zodiac and the solar system with world at centre.

Developments in cosmology have taken many twists and turns since the birth of the scientific enlightenment in the 16th Century. Over the last 400 years, the science of cosmology has progressed from an initial state of uncertainty using rudimentary instruments for observation and measurement and intuitive mathematics. It is now placed on a firm empirical and theoretical base with the aid of powerful and accurate instruments in a variety of domains and fully mature mathematical tools.

The table below illustrates the key developments during this exciting history, highlighting the dominant scientists and experimental advances. Follow the trajectory from the demise of the Ptolemaic geocentric view in the mid-16th Century to the latest developments of the Standard Model of cosmology in the present day.

Table 1 – Major developments in the history of the science of cosmology

Date Description


Nicolaus Copernicus publishes his On the Revolutions of the Heavenly Spheres, challenging the dominant geocentric view of the universe and ushering in the Copernican Revolution with his heliocentric model.


French philosopher, René Descartes, resurrects the ancient Greek atomist model in his The World. He sees the universe composed of corpuscles of matter that constantly swirl in vortices and fill up all of space.


Alexander Baumgarten, in his Metaphysics, argues that cosmology properly belongs to metaphysics because it contains the first principles of psychology, physics, theology, teleology and practical philosophy.


Immanuel Kant, in his Universal Natural History Interior of the Heavens: Essay on the Constitution and the Mechanical Origins of the Whole Universe According to Newtonian Principles, advances the idea that stars and planets form from slowly rotating gaseous clouds that gradually collapse and flatten due to the effects of gravity.


Albert Einstein publishes his Special Theory of Relativity, generalising Galileo's Principle of Relativity to apply not only to terrestrial mechanics but to all the laws of physics. He posits that space and time are not separate continua and that the speed of light is the same for all frames of reference.


Vesto Melvin Slipher measures the Doppler shift of receding galaxies. These measurements were later used by Edwin Hubble to demonstrate empirically that the universe is expanding.


Albert Einstein publishes his General Theory of Relativity in which he unifies Special Relativity and Newton's Law of Universal Gravitation and describes how gravity is a property of the curvature of four-dimensional space-time. Key predictions of his theory are the deflection of starlight by the gravity of the Sun and the advance of the precession of the perihelion of Mercury.


Albert Einstein publishes his paper, 'Kosmologische Betrachtungen zur allgemeinen Relativitaetstheorie', introducing the 'cosmological constant' into his General Theory of Relativity. He thought this move necessary in order to account for the observation that the universe is not collapsing; a move he later regretted, calling it his 'greatest blunder'.


Willem de Sitter, in his paper 'On Einstein's Theory of Gravitation and Its Astronomical Consequences: Third Paper', provided the first model of an exponentially expanding universe dominated by the cosmological constant.


During an expedition to view a solar eclipse, Arthur Eddington records the deflection of starlight by the Sun's gravity, confirming Einstein's General Theory of Relativity. The results were confirmed again by William Wallace Campbell with his observations in 1922.


Alexander Friedmann, using Einstein's General Theory of Relativity field equations, plots the expansion of the universe backwards to the Big Bang. For a universe with positive curvature (spherical space), the equations result in an oscillating universe.


Edwin Hubble settles the debate about the nature of spiral nebulae and the size of the universe with his measurement of distances to some nearby spiral nebulae. His measurements locate them far outside our Milky Way galaxy and shows that the universe is composed of many thousands of such galaxies.


Physicist and Roman Catholic priest, Georges Lemaître, uses Einstein's field equations to propose an expanding universe before Hubble's corroborating evidence in 1929 and to derive Hubble's Law. He successfully predicted the value of the Hubble constant.


By measuring the red shift of galaxies, Edwin Hubble determined that galaxies are receding from us at a rate proportional to their distance, as predicted by the Big Bang theory. He formulated Hubble's Law: V = HD (where V = velocity; H is a constant; D = distance).


Georges Lemaître traces the expanding universe back in time to when space and time themselves began with quantum fluctuations in a vacuum; back to the time of the Big Bang.


Fritz Zwicky and Walter Baade propose that supernovas are a transitional phase in a star's life cycle from a normal star to a neutron star. A key prediction of their model is the emission of cosmic rays from supernova.


Applying the virial theorem to his observations of the Coma cluster of galaxies, Fritz Zwicky deduces the existence of dark matter holding galaxies together. He accurately calculated that galaxies are comprised of 90% dark matter and predicted the effects of gravitational lensing.


Using the cosmological principle, Fred Hoyle, Thomas Gold and Hermann Bondi propose a steady state universe in opposition to the standard Big Bang model. In a steady state universe, matter is constantly created and inserted as the universe expands, thus maintaining a constant density.


Ralph Alpher, Robert Herman and George Gamow analysed the conditions moments after the Big Bang to propose how complex elements are formed from nucleosynthesis. They accurately predicted the temperature of the residual cosmic microwave background (CMB) radiation.


Fred Hoyle uses the term 'Big Bang' for the first time to contrast it with his steady state model.


Robert Dicke introduces the weak anthropic principle; the principle that we as observers can only exist in a universe where the force of gravity is weak, allowing stars to burn for eons and carbon-based life to evolve.


Arno Penzias and Robert Wilson from Bell Telephone Laboratories measure the cosmic microwave background (CMB) radiation generated 380,000 years after the Big Bang. The measurements validate the predictions of Ralph Alpher, Robert Herman and George Gamow in 1948 and disprove Fred Hoyle's steady state model of the universe.


James Peebles, in his 'Primordial Helium Abundance and the Primordial Fireball. II', shows how the Big Bang model predicts the correct abundance of helium in the current universe.


Robert Wagoner, William Fowler and Fred Hoyle, in their 'On the Synthesis of Elements at Very High Temperatures', show how the Big Bang model predicts the correct abundances of deuterium and lithium in the current universe.


Measuring spiral galaxy rotation curves, Vera Rubin and Kent Ford reveal galaxies to contain 90% dark matter. This data vindicates Fritz Zwicky's dark matter predictions made in 1934.


Alan Guth and Alexei Starobinsky independently propose a modification of the standard Big Bang model to incorporate a period of rapid inflation in order to solve the horizon and flatness problems of the Big Bang model.


Viatcheslav Mukhanov and Gennady Chibisov propose that the initial quantum fluctuations at the time of the Big Bang result in the large scale structure in an inflationary universe. Their model predicted the degree of temperature fluctuations in the cosmic microwave background (CMB) radiation.


James Peebles, J. Richard Bond, George Blumenthal and others propose that cold dark matter makes up about 80% of the matter in the universe.


Mordehai Milgrom proposes his rival Modified Newtonian Dynamics (MoND) theory to the existence dark matter. On his theory, attractive gravitational forces become very small at large distances from the galactic centre.


M. Davis, G. Efstathiou, C. S. Frenk and S. D. M. White run large computer simulations of the formation of cosmic structures. The simulations match closely observations related to cold dark matter but fail for hot dark matter.


Preliminary results from NASA's COBE mission confirm with a precision of one part in 105 that the cosmic microwave background (CMB) radiation is consistent with a blackbody spectrum. This result disproves the integrated starlight model proposed for the CMB by steady state model theorists.


Further COBE measurements reveal the miniscule anisotropy of the cosmic microwave background (CMB) radiation. The observed fluctuations of 1 part in 100,000 or 1°K across the universe show the seeds of large-scale structure when the universe was around 1/1100th of its present size and 380,000 years old.


Saul Perlmutter, heading the Supernova Cosmology Project, and Brian Schmidt, heading the High-Z Supernova Search Team, independently discover cosmic acceleration based on distances to Type Ia supernovae. These observations provide the first direct evidence for a non-zero cosmological constant and an accelerating expansion of the universe.


The BOOMERanG experiment and others make finer measurements of the cosmic microwave background (CMB) radiation, providing evidence for oscillations (the first acoustic peak) in the anisotropy angular spectrum. These results are predicted by the standard Big Bang model of cosmological structure formation and show the geometry of the universe to be close to flat.


The Two-degree-Field Galaxy Redshift Survey (2dFGRS), headed by Matthew Colless, Steve Maddox and John Peacock, shows that the matter density in the universe is nearly 25% of the critical density. Conjoined with the results for a flat universe, the results provide independent evidence for a non-zero cosmological constant and for dark energy.


High resolution measurements of the cosmic microwave background (CMB) radiation obtained with the Cosmic Background Imager (CBI) in Chile reveal an anomaly with measurements expected using the standard Big Bang model at high-l multipoles (CBI-excess).


Using M-theory, superstring theory and brane cosmology, Paul Steinhardt and Neil Turok propose a variation on the inflating universe model. On this cyclic model, the universe expands and contracts in cycles.


Measurements of the brightest cosmic microwave background (CMB) fluctuations by NASA's Wilkinson Microwave Anisotropy Probe (WMAP) confirms that the universe is 13.7 billion years old and that the topology of the universe is flat.


The Sloan Digital Sky Survey (SDSS) and 2dF redshift survey both detected the baryon acoustic oscillation feature in the galaxy distribution, a key prediction of cold dark matter models.


Release of the three-year Wilkinson Microwave Anisotropy Probe (WMAP) data on the temperature and polarization of the cosmic microwave background (CMB) radiation confirms the standard flat Big Bang model and reveals new evidence in support of inflation.


Release of the five-year Wilkinson Microwave Anisotropy Probe (WMAP) data shows new evidence for the cosmic neutrino background. It also lent support to the theory that the first stars reionized the universe after more than half a billion years after the Big Bang and added additional constraints on cosmic inflation.


Release of the seven-year Wilkinson Microwave Anisotropy Probe (WMAP) data confirms that the universe is made up of 73% dark energy, 23% dark matter and 4% ordinary, baryonic matter.


Release of the nine-year Wilkinson Microwave Anisotropy Probe (WMAP) data shows that 95% of the early universe is composed of dark matter and energy and that the curvature of space is very close to flat.


The BICEP2 experimental data tentatively supported the theory of cosmic inflation by detecting gravitational waves. The results were dismissed in early 2015, attributing the initial positive result to noise emission from galactic dust.


The two aLIGO (Advanced Laser Interferometer Gravitational-Wave Observatory) instruments independently detect gravitational waves for the first time from a pair of merging black holes.

If you feel you can contribute to the development of this timeline, contact us with your suggestions. We are particularly interested in identifying the key predictions of each new model and how they were vindicated.

Copyright © 2015, 2016

First published Jul 14, 2015
Minor revision  Feb 29, 2016 (Updated timeline)

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