Astronomy is probably the oldest science known to man, and our understanding of the Universe has developed gradually over centuries of observing the stars, Moon and planets to reach the considerable level of knowledge we possess today.
Early History
Some of the earliest astronomical records kept were by the Babylonians and the Chinese, in around 3,000 B.C.
Between 600 B.C.and 130 B.C. Greeks such as Pythagoras, Thales of Miletus, Plato, and Aristotle proposed a geocentric model of the Universe, whereby all objects in the sky circled the Earth.
In 280 B.C. Aristrachus of Samos was credited with suggesting the first heliocentric theory, whereby it was the Earth and planets which revolved around a stationary Sun at the center of the Universe. However, his theory was not generally accepted and Ptolemy further refined the original geocentric model in his 140 A.D masterpiece 'Almagest,' which was accepted by the western world for the next 1500 years.
In 280 B.C. Aristrachus of Samos was credited with suggesting the first heliocentric theory, whereby it was the Earth and planets which revolved around a stationary Sun at the center of the Universe. However, his theory was not generally accepted and Ptolemy further refined the original geocentric model in his 140 A.D masterpiece 'Almagest,' which was accepted by the western world for the next 1500 years.
Astronomy of The Renaissance
Modern astronomy began to take shape in 1543, when Copernicus published his “De Revolutionibus Orbium Coelestium” which used empirical evidence to support a heliocentric view of the Universe, and Tycho Brahe compiled detailed observations on the positions of the planets.
In around 1605, four years after Brahe's death, his assistant and successor Johannes Kepler observed that the planets moved in elliptical orbits around the Sun, and so proposed his three laws of planetary motion.
Galileo then added to the growing body of scientific astronomy data by using 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.
However, the church was a major power in 16th century Europe, and Galileo's attempts to defend the heliocentric model of the Universe, and cite sunspots as proof of the imperfection of the heavens landed him in direct conflict with the Holy Inquisition. In 1632, he was tried by the church for heresy, forced to recant his theories and was condemned to spend the rest of his life under house arrest. It wasn't until 1922 that he was finally absolved by the Vatican for his views.
By 1687, Sir Isaac Newton had invented a new telescope which used a curved mirror instead of a lens to look further into space, and he had published his hugely influential book called 'Philosophiae Naturalis Principia Mathematica.' Newton agreed that the Earth rotated around the Sun and explained the reasons behind Kepler's three laws. He also established the law of universal gravitation, which ushered in a new Age of physics and Enlightenment
Up To Modern Times
Since then mankind has done a pretty thorough job mapping the stars, planets and their moons, and compiling a whole catalogue of astronomical objects and predicting their nature.
In 1798 for instance, Laplace proposed the concept of Black Holes, and by 1817 Charles Messier had compiled a list of 103 deep sky objects he identified as not comets, and which included nebulae, star clusters, and galaxies.
Since then mankind has done a pretty thorough job mapping the stars, planets and their moons, and compiling a whole catalogue of astronomical objects and predicting their nature.
In 1798 for instance, Laplace proposed the concept of Black Holes, and by 1817 Charles Messier had compiled a list of 103 deep sky objects he identified as not comets, and which included nebulae, star clusters, and galaxies.
Astrophysics received a major boost in 1900 when Max Planck invented quantum mechanics and Einstein's two theories of Special and General Relativity changed the way we viewed the structure of spacetime and gravity forever.
By the mid-1900's Edwin Hubble had proved that galaxies were separate systems outside of our own Milky Way and that the Universe was expanding. Mankind has now walked on the Moon, established Space Stations in orbit around the Earth and discovered more than 400 planets outside of our Solar System.