How geometry informed cosmology in antiquity and the middle ages University of Lincoln 22 January 2012 Robert Grosseteste International Conference Dr Simon Mitton , St Edmund’s College, University of Cambridge QuickTime™ and a decompressor are needed to see this picture Summary This is a PowerPoint presentation of my paper on the importance of geometry in the history of cosmology. It features Plato, Aristotle, Hipparchus of Niceae, Ptolemy of Alexandria, Robert Grosseteste, Galileo Galilei, Nicolaus Copernicus, and Isaac Newton. The TEXT of the lecture can be viewed and downloaded at http://www.totalastronomy.com/seminars/index .php
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How geometry informed cosmology in antiquity and the middle ages University of Lincoln 22 January 2012 Robert Grosseteste International Conference Dr Simon.
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How geometry informed cosmology in antiquity and the middle ages
University of Lincoln 22 January 2012Robert Grosseteste International Conference Dr Simon Mitton , St Edmund’s College,
University of Cambridge
QuickTime™ and a decompressor
are needed to see this picture.
Summary
This is a PowerPoint presentation of my paper on the importance of geometry in the history of cosmology.
It features Plato, Aristotle, Hipparchus of Niceae, Ptolemy of Alexandria, Robert Grosseteste, Galileo Galilei, Nicolaus Copernicus, and Isaac Newton.
The TEXT of the lecture can be viewed and downloaded athttp://www.totalastronomy.com/seminars/index.php
Before you begin …Here is a “plug” for my biography of the astronomer Fred Hoyle (1915-2001). Features• The only biographical account of Fred Hoyle written from personal knowledge• Focuses on Hoyle's contributions to science as an astronomer and public figure• A fascinating insight into the history of cosmology• He coined the term Big Bang for the origin of the universe•He worked with Hermann Bondi, Thomas Gold, Willy Fowler, Geoff and Margaret Burbidge, and DonClayton, all of whomfeature in this biography.
Greek natural philosophy was unique in that the thinking style was rational and testable.
The scope of enquiry far exceeded that of any other civilisation, some of whom were skilled at astronomy for a thousand years before the Greeks looked to the heavens for answers to deep questions.
The “Unique Selling Feature” of Greek astronomy is the skilful use of geometry to account for the mechanism of the heavens
Cosmic enquiry in antiquity
For about six centuries the philosophers of ancient Greece were the only intellectuals who conducted
theoretical astronomy.
Plato’s greatest contribution to cosmology was his insistence that geometry was the key to unlocking the secrets of the universe.
He analysed the fundamental elements in terms of mathematical solids. The sphere is the most perfect of the regular solids, from which Plato concluded that the universe is spherical and orbits are circles.
Aristotle introduced a search for causes. The stars are fixed to a distant sphere. Earth is at the centre of the universe.
In Aristotle’s cosmology each planet has its own spheres of influence. Interactive motion of the spheres produces the irregularities of planetary motion
Cosmology gets technical
Fourth century BC Eudoxus of Cnidos produces first fully worked out model with 27 concentric spheres Third century BC Aristarchus of Samos uses geometry to get relative sizes of Sun and Moon
Third century BC Eratosthenes of Cyrene measures the size of the Earth
Hipparchus of Niceae
• Built a marvellous observatory• First systematic observer. Kept detailed records of
star positions• He measured angular distances between the
planets and fixed stars.• Invented the coordinate system still used in
astronomy• Invented the scale of star magnitudes• Introduces 360 degrees into the geometry of the
circle. First trigonometrical tables• Discovers the precession of the equinoxes
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Ptolemy Almagest
Ptolemy Almagest
Ptolemy Almagest
Nicholas Copernicus 1473 - 1543
Nicholas Copernicus 1473 - 1543
Nicholas Copernicus 1473 - 1543
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What Galileo’s telescope showed
Milky Way composed of millions of stars
What Galileo’s telescope showed
What Galileo’s telescope showed
What Galileo’s Dialogo caused
Newton’s Principia
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decompressorare needed to see this picture.
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And finally …Here is a “plug” for my biography of the astronomer Fred Hoyle (1915-2001). Features• The only biographical account of Fred Hoyle written from personal knowledge• Focuses on Hoyle's contributions to science as an astronomer and public figure• A fascinating insight into the history of cosmology• He coined the term Big Bang for the origin of the universe•He worked with Hermann Bondi, Thomas Gold, Willy Fowler, Geoff and Margaret Burbidge, and DonClayton, all of whomfeature in this biography.