A brief chronological listing of some of the most important discoveries in cosmology, astronomy and physics, from ancient Babylon, India and Greece, right up to the 20th Century. Learn how some of the essential concepts and laws of modern physics which are mentioned in this website (and the earlier ideas out of which they grew) developed in a historical context. For a slightly different perspective, also see the section on Cosmological Theories Through History.
For convenience I have split it into sections:
Ancient World (20th Century B.C. - 4th Century A.D.)
Medieval and Renaissance World (5th Century A.D. - 16th Century)
Early Modern World (17th Century - 19th Century)
Modern World (20th Century)
ANCIENT WORLD Back to Top
20th -16th Century B.C. - Ancient Babylonian tablets show knowledge of the distinction between the moving planets and the "fixed" stars, and the recognition that the movement of planets are regular and periodic.
15th - 12th Century B.C. - The Hindu Rigveda of ancient India describes the origin of the universe in which a "cosmic egg" or Brahmanda, containing the Sun, Moon, planets and the whole universe, expands out of a single concentrated point before subsequently collapsing again, reminiscent of the much later Big Bang and oscillating universe theories.
5th Century B.C. - The Greek philosopher Anaxagoras becomes arguably the first to formulate a kind of molecular theory of matter, and to regard the physical universe as subject to the rule of rationality or reason.
5th Century B.C. - The Greek philosophers Leucippus and Democritus found the school of Atomism, which holds that the universe is composed of very small, indivisible and indestructible building blocks known as atoms, which then form different combinations and shapes in an infinite void.
(Click for a larger version)
Geocentric universe of Aristotle and Ptolemy
(Source: Cartage.org: http://www.cartage.org.lb/en/
themes/sciences/mainpage.htm)
4th Century B.C. - The Greek philosopher Aristotle describes a geocentric universe in which the fixed, spherical Earth is at the centre, surrounded by concentric celestial spheres of planets and stars. Although he portrays the universe as finite in size, he stresses that it exists unchanged and static throughout eternity.
4th Century B.C. - The Greek philosopher Heraclides proposes that the apparent daily motion of the stars is created by the rotation of the Earth on its axis once a day, and that the Sun annually circles a central Earth, while the other planets orbit the Sun (a geocentric model with heliocentric aspects).
3rd Century B.C. - The Stoic philosophers of ancient Greece assert a kind of "island universe" in which a finite cosmos is surrounded by an infinite void (similar in principle to a galaxy).
3rd Century B.C. - The Greek mathematician and geographer Eratosthenes proved that the Earth was round, and made a remarkably accurate calculation of its circumference and its tilt (as well as devising a system of latitude and longitude, and, possibly, estimating the distance of the Earth from the Sun).
3rd Century B.C. - The Greek astronomer and mathematician Aristarchus of Samos is the first to present an explicit argument for a heliocentric model of the Solar System, placing the Sun, not the Earth, at the center of the known universe. He describes the Earth as rotating daily on its axis and revolving annually about the Sun in a circular orbit, along with a sphere of fixed stars.
2nd Century B.C. - The Greek astronomer Hipparchus of Nicea makes the first measurement of the precession of the equinoxes,
2nd Century B.C. - The Hellenistic astronomer and philosopher Seleucus of Seleucia supports Aristarchus' heliocentric theo
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