Since prehistoric times our ancestors gazed up at the stars and observed the movements of the Sun and Moon. Not surprisingly, astronomy is probably the oldest science known to man and over the passing centuries our understanding of the Universe has developed gradually to reach the considerable level of knowledge we possess today. What follows are some key dates in the timeline of astronomy:
10,000+ BCE: To ancient man the sky was the home of the gods and so early astronomers were holy men interpreting the will of the gods through careful study mixed with religion and astrology. Astronomy was also an important component of human life and could be used as a method to predict the cycle of the seasons for agricultural purposes, as well as for measuring time and direction.
4900 BCE: The Goseck circle built and considered the earliest sun observatory showing ancient peoples accurately measuring the heavens.
3,000 BCE: Earliest astronomical records and star catalogs being kept by the Sumerians, then Babylonians and later the Egyptians.
2137 BCE: Chinese record earliest known solar eclipse.
1450 BCE: The Egyptians start to use sundials.
800 BCE: Indian astronomer Yajnavalkya proposes a heliocentric concept of the universe in which the Earth is spherical and the Sun is at “the centre of the spheres.”
600 to 130 BCE: Greeks first to develop astronomy from being an observational science related to religion into a theoretical science about the structure of the universe. Pioneers during this period include Pythagoras, Thales, Plato and Aristotle who proposed a geocentric model of the Universe with the sun circling the Earth.
280 BCE: Greek astronomer Aristrachus of Samos suggests a heliocentric theory of the universe, whereby it was the Earth and planets which revolved around a stationary Sun. However, his theory was not popular and it would be nearly 1800 years before it would be accepted.
150 BCE: Ancient astronomical computer, the Antikythera mechanism constructed in ancient Greece capable of predicting star and planet positions, as well as lunar and solar eclipses. (reproduced opposite)
1543 A.D: During the Renaissance period modern astronomy began to take shape when Copernicus published his “De Revolutionibus Orbium Coelestium” which used empirical evidence to revive Aristrachus’ heliocentric view of the Universe,
1576 A.D: Tycho Brahe compiles accurate and comprehensive observations on the positions of the planets to further credit the Copernican system over the Ptolemaic one.
1605 A.D: Johannes Kepler discovered that the planets orbit about the sun in an elliptical and not circular motion, and so proposed his three laws of planetary motion.
1608 A.D: Dutch spectacles maker Hans Lippershey invents a refractor telescope.
1609 A.D: Galileo used the newly invented telescope to make some incredible astronomical observations, including viewing Jupiter’s rotating moon system, and noting there were obviously objects in the heavens which didn’t revolve around the Earth. Galileo’s attempts to defend the heliocentric model of the Universe landed him in direct conflict with the powerful church. In 1632 he was tried for heresy, forced to recant and condemned to spend the rest of his life under house arrest.
1668 A.D: Sir Isaac Newton invented the first reflecting telescope which used a curved mirror instead of a lens to look further into space. Newton later publishes his hugely influential book called ‘Philosophiae Naturalis Principia Mathematica’ in which he agrees that the Earth rotates around the Sun and explains the reasons behind Kepler’s three laws. He also establishes the law of universal gravitation, which ushered in a new Age of physics and Enlightenment.
1781 A.D: Messier discovers and catalogs numerous galaxies, nebula and star clusters.
1798 A.D: Laplace proposes the concept of Black Holes.
1905 A.D: Albert Einstein introduces special Theory of Relativity then in 1916 his general Theory of Relativity.
1923 A.D: Edwin Hubble working at Mount Wilson Observatory (photo) and using a 60 inch reflector telescope proves that galaxies are separate systems outside of our own Milky Way and that the Universe was expanding.
1937 A.D: First radio telescope built in the USA by Grote Reber.
1957 A.D: Russian Sputnik 1 satellite becomes the first man-made object to orbit the Earth marking the beginning of the space age.
1969 A.D: Neil Armstrong and Buzz Aldrin walk on the Moon as part of the Apollo 11 mission.
1977 A.D: Voyager 1 spacecraft launched to explore the outer Solar System.
1990 A.D: The Hubble Space Telescope (HST) is put into orbit from space shuttle Discovery. The 2.4m aperture reflecting telescope continues to circle the Earth taking extremely sharp images of outer space.
1992 A.D: Radio astronomer Wolszczan and Frail announce the discovery of the first definitive detection of exoplanets. Over the intervening years hundreds of planets outside of our solar system have now been confirmed.
See also: History of Astronomy