We could imagine this as spheres rolling around each other. Claudius Ptolemy, writing in Alexandra in the 2nd century, finished this project, creating the greatest work of the ancient world, his masterpiece, the Almagest. This book contains a complete account of the motions of all of the objects in the night sky viewable without a telescope, and perfectly describes the trajectory of each.
To get this degree of accuracy, Ptolemy relied on some intricate mathematical tools: epicycles—circles in circles and then circles in circles in circles; eccentricities—squished circles; and ecliptics—off-centered circles. We would combine these to create the great cosmic spirograph that never missed a prediction.
So, the book was simply known as The Great Work. Learn more about defining reality. This was the state of science at the beginning of the Christian era. We find important advances during this period among Indian scholars—especially in mathematics, Chinese scholars—largely in medicine and mathematics, and Muslim scholars—in astronomy and physics. These traditions developed in accord with their own cultural contexts, but as a result of global trade, there is still a Greek heart in the development that came after.
In Western Europe, we see the Dark Ages at this time, during which little scientific interest emerged. Augustine in the 5th century finds in Plato an intellectual foundation for Christianity, one that would systematize it and philosophically justify it.
On the one hand, we have the material world around us, a false corrupted representation of reality. Whereas, on the other hand, we have the world of forms, a nonmaterial world of perfection. This picture was easily tweaked to map onto Christian theological teachings, in which reality is comprised of two realms, one, a sinful, diseased world of flesh and two, an eternal, perfect world of spirit.
So, following Augustine there was a strong line of Christian neo-platonic thought. The depth presented here nonetheless probably goes beyond that required by the NSW syllabus. In doing so it should provide some background to what is a fascinating topic. The ancient Greeks, specifically the Ionian school of philosophers, are credited with the move to a natural, mechanistic view of the Universe. Based on Miletus in Asia Minor and founded by Thales , the Ionians are remembered not so much for the specific models of the Universe that they suggested, but rather that they asked questions that they could then attempt to answer through reason, observation and the application of geometry.
Anaximander refined Thales' ideas and proposed a model which had a cylindrical Earth at rest in the centre of the Universe, surrounded by air then one or more spherical shells with holes in them.
These appeared as stars due to the rim of fire that lay beyond the solid sphere. Anaximander's model of the Universe was revolutionary for two main reasons. Firstly it introduced a mechanistic view, moving beyond a mythological, supernatural explanation for the Universe. It also proposed the concept of spheres surrounding the Earth. This was to profoundly influence astronomy and cosmology for the next two millennia.
Anaximenes refined Anaximander's model by suggesting that the stars were fixed on to a solid, transparent crystalline sphere that rotated about the Earth. Later Ionians contributed more ideas and discoveries. Anaxogoras c. Empedocles suggested that light traveled fast but not at infinite speed. Democritus proposed not just at atomist model of matter but also proposed that the Milky Way was composed of thousands of unresolved stars.
Pythagoras c. He and his followers believed in the concept of cosmos , a well-ordered, harmonious Universe. They placed great importance on the power and aesthetics of geometry and mathematics rather than experiments. Regular geometrical solids, especially the sphere, were revered and they sought to find harmonies and ratios in the natural world.
Herakleides , a student of Plato and Aristotle but heavily influenced by Pythagorean ideas refined an earlier model by Philolaus to develop one that had a spherical Earth rotating on it axis. It also had Mercury and Venus revolving around the Sun whilst the Sun and other planets revolved around the Earth.
Stars again were fixed on a revolving crystalline sphere. Models that had the Earth at the centre of the Universe are termed geocentric or earth-centered. Interestingly whilst most classical models were variations on geocentric models, one of the Pythagoreans, Aristarchus of Samos c. His model would be familiar to us today as a reasonable description of the solar system.
All the planets, including the earth, revolved around a fixed Sun in circular orbits. The Earth rotated once a day on its axis and the Moon revolved about the Earth. There are several reasons why Aristarchus' model did not gain wide acceptance and was in effect lost for 18 centuries until Copernicus redeveloped it. Firstly his original writings were lost in the destruction of the Great Library of Alexandria in AD Secondly his concept of a moving Earth defies common sense.
The exception, a century later, was Aristarchus, one of the earliest believers in a heliocentric or sun-centered universe. In the s BC, Hipparchus, the most important Greek astronomer of his time, calculated the comparative brightness of as many as 1, different stars. He also calculated the Moon's distance from the Earth.
The first astronomer to make truly scientific maps of the heavens, Claudius Ptolemaeus better known as Ptolemy of Alexandria , came along years later. Like most astronomers before him, he believed the Sun, Moon, and other planets circled the Earth. He thought that each space body moved in a small circle an epicycle that was itself orbiting Earth.
This explained why planets sometimes appeared to travel backward in the sky. The Earth-centered view of the universe was widely accepted for about years. It was not seriously challenged until , when the Polish monk Nicolaus Copernicus suggested that the Sun was at the center of the universe.
Because the Church taught that the Earth was central, Copernicus' theory was regarded as heresy. Perhaps this is why he did not want it published until after his death. Copernicus' published theory, On the Revolution of the Celestial Spheres , met with great hostility from the Church. The two events most responsible for eventual acceptance of Copernicus' views were Tycho Brahe's precise observations of the sky and Galileo's use of the telescope.
One night in , Danish astronomer Tycho Brahe saw what he thought was a brilliant new star in the constellation Cassiopeia. We now know he was observing a supernova. In , a second supernova was observed. These discoveries caused scientists to seriously question Ptolemy's theory that all stars were contained in an outermost sphere of the universe that never changed. In , Italian scientist Galileo Galilei heard about the invention of a spyglass.
He made one for himself and turned it on the heavens. Recentering the Universe An page round-up of how these early scientists' work changed everything about people understood their world. Articles on many early astronomers can be can be found in our online databases: Biography in Context and Encyclopaedia Britannica English, Spanish, and children's versions. Aristotle Leads the Way Captures the life and times of Aristotle, the ancient Greek philosopher who studied a wide range of subjects and helped shape early scientific beliefs.
In our young adult collection. The Great Thinker Stresses the importance of Aristotle's intellectual discoveries on the future of science. Biography for Kids: Aristotle A short online biography of Aristotle good for upper elementary grades that touches on some important points.
Copernicus An enjoyable page biography of the 16th-century Polish scientist that includes activities on retrograde motion, the solar system, parallax, and an astrolabe. Nicolaus Copernicus The center of the universe -- A childhood in Poland -- A long-term student -- In the service of the church -- Look to the stars -- The Copernican theory -- Late in life -- A scientific revolution -- Late in life -- Life at a glance.
The History News in Space Uses a newspaper format to take a look at developments that led from the ideas of Copernicus and other early scientists to the technological advances that enabled man to venture to the moon and beyond. Galileo A biography of 17th-century Italian astronomer and physicist Galileo that includes related activities for readers. Galileo for Kids This biography has experiments and activities as well as his life story. Starry Messenger A beautiful retelling, in picture book format, of Galileo's story which can be used with both younger and older audiences.
The Galileo Project A hypertext online source of information on the life and work of Galileo Galilei and the science of his time. Includes a biography, letters from his daughter, and a tour of his home. From Rice University. Galileo's Battle for the Heavens An online timeline of his life, articles on his place in science and his telescope, his mistakes on predicting the tides, a teachers' guide, and interactives on his experiments with falling objects, projectiles, inclined planes, and pendulums.
Who Was Galileo? A page biography with illustrations and maps. Part of the "Who Was" series. Also available on eAudio. Ptolemy's World Lots of illustrations of Ptolemy's geography, a note on his principle of simplicity, and links to his texts. Skip to main navigation Skip to main navigation Skip to search Skip to search Skip to content.
Use current location. See all locations. Admin Admin Admin, collapsed. Main navigation Events. Open search form. Enter search query Clear Text. Saved Searches Advanced Search.
0コメント