Astronomy 161 - Introduction to Solar System Astronomy - Autumn 2007 episodes:

• October 12, 2007Lecture 17: On the Shoulders of Giants: Isaac Newton and the Laws of Motion

  Copernicus, Kepler, Tycho, and Galileo together gave us a new way of

  looking at the motions in the heavens, but they could not explain why

  the planets move they way the do. It was to be the work of Isaac Newton

  who was to sweep away the last vestiges of the Aristotelian view of the

  world and replace it with with a new, vastly more powerful predictive

  synthesis, in which all motions, in the heavens and on the Earth, obeyed

  three simple, mathematical laws of motion. This lecture introduces

  Newton's Three Laws of Motion and their consequences. Recorded 2007 Oct

  12 in 1000 McPherson Lab on the Columbus campus of The Ohio State

  University.

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• October 11, 2007Lecture 16: The Starry Messenger - Galileo and the Telescope

  Tycho reached the limits of what could be done with the naked eye. A

  new technology was required to extend our vision: the telescope. This

  lecture introduces Galileo Galilei, the contemporary of Kepler who was

  in many ways the first modern astronomer, and describes his many

  discoveries with the telescope. These observations electrified Europe

  in the early 17th century, and set the stage for the final dismantling

  of the Aristotelian view of the world. Galileo's claims that they

  constituted proof of the Copernican Heliocentric System, however, were

  to bring him into conflict with the Roman Catholic Church. Recorded

  2007 Oct 11 in 1000 McPherson Lab on the Columbus campus of The Ohio

  State University.

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• October 10, 2007Lecture 15: The Watershed - Tycho and Kepler

  In the generation following Copernicus, the question of planetary

  motions was picked up by two remarkable astronomers: Tycho Brahe and

  Johannes Kepler. Tycho was a Danish nobleman and brilliant astronomer

  and instrument builder whose high precision naked-eye measurements of

  the stars and planets were to be the summit of pre-telescopic astronomy.

  Kepler was the talented German mathematician who was hired by Tycho and

  succeeded him after his death who was to use Tycho's data to derive his

  three laws of planetary motion. These laws swept away the vast complex

  machinery of epicycles, and provide a geometric description of planetary

  motions that was to set the stage for their eventual physical

  explanation by Isaac Newton a generation later. Recorded 2007 Oct 10 in

  1000 McPherson Lab on the Columbus campus of The Ohio State University.

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• October 09, 2007Lecture 14b: Copernicus from Au2006

  Because my voice recorder malfunctioned 15 minutes into my Lecture on

  Copernicus on 2007 October 9, I've added this recording of my Copernicus

  lecture from Autumn Quarter 2006. It is the same basic material, but

  since I generally improvise on a basic outline, there will be some

  differences. Personally, I liked this year's lecture better, but this

  will at least cover most of the same material. Oh well.

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• October 09, 2007Lecture 14: The Revolutions of Nicolaus Copernicus

  In 1543, Nicolaus Copernicus revived Aristarchus' Heliocentric System in

  an attempt to rid Ptolemy's geocentric system of the un-Aristotelian

  idea of the Equant. He desired to create a model of the planets that

  would please the mind as well as preserving appearances. Rather than

  reinstate the ideal of the Aristotelian World View, he was to set the

  stage for its overthrow after nearly 2000 years of supremacy, and within

  two centuries give birth to the modern world.

  This lecture describes the astronomical world from the end of the classical

  age until the birth of Copernicus, and then describes his revolutionary

  idea of putting the Sun, and not the Earth, at the center of the Universe.

  Recorded 2007 Oct 9 in 1000 McPherson Lab on the Columbus campus of The

  Ohio State University. NOTE: Due to a recorder malfunction, only the

  first 15 minutes of this lecture was recorded.

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• October 08, 2007Lecture 13: The Harmony of the Spheres - Greek Astronomy

  What are the origins of the Geocentric and Heliocentric models

  put foward to explain planetary motion? This lecture begins a new

  unit that will chart the rise of our modern view of the solar system by

  reviewing the highly influential work by Greek and Roman philosophers

  who elaborated the first geocentric and heliocentric models of

  the Solar System. We discuss the various geocentric systems from

  the simple crystaline spheres of Anaximander, Eudoxus, and Aristotle

  through the Epicyclic systems of Hipparchus and Ptolemy. We will

  also briefly discuss what is known of Aristarchus' mostly-lost heliocentric

  system, which was to so strongly influence the work of Copernicus. The

  ultimate expression of an epicyclic Geocentric system was that

  described by Claudius Ptolemy in the middle of the 2nd Century AD, and

  was to prevail virtually unchallenged for nearly 14 centuries.

  Recorded 2007 Oct 8 in 1000 McPherson Lab on the Columbus campus

  of The Ohio State University.

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• October 04, 2007Lecture 12: The Wanderers

  How do the planets move across the sky? This lecture discusses the

  motions of the 5 naked-eye planets (Mercury, Venus, Mars, Jupiter, and

  Saturn) as seen from the Earth. We introduce the major configurations

  of the planets, and then discuss their apparent retrograde motions. The

  apparent motions of the planets are far more complex than those of the

  Sun, Moon, and stars, and present a great challenge to understand. The

  centuries long effort to understand these motions was to give birth to

  modern science. Recorded 2007 Oct 4 in 1000 McPherson Lab on the

  Columbus campus of The Ohio State University.

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• October 03, 2007Lecture 11: The Calendar

  How do we make calendars? This lecture explores the astronomical

  origins of our calendars. We start by discussing lunar and solar

  calendars and their hybrids in history and tradition (for example, the

  Islamic Lunar Calendar and the Hebrew Luni-Solar Calendar), and then

  describe the Julian and Gregorian Calendar reforms that attempt to align

  the calendar with the seasons of the year with greater degrees of

  precision. Recorded 2007 Oct 3 in 1000 McPherson Lab on the Columbus

  campus of The Ohio State University.

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• October 02, 2007Lecture 10: Telling Time

  What time is it? Telling time is the oldest practical application of

  astronomy. Today's lecture is the first of a 2-part lecture on the

  astronomical origins of our methods of keeping time and making

  calendars. This lecture reviews the divisions of the year into the

  solstices, equinoxes, and cross-quarter days, the division of the year

  into months by moon phase cycles, months into weeks, and the division

  of the day into hours by marking the location of the Sun in the sky

  Recorded 2007 Oct 2 in 1000 McPherson Lab on the Columbus

  campus of The Ohio State University.

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• October 01, 2007Lecture 09: Eclipses of the Sun and Moon

  Among the most amazing sights in the sky, eclipses of the Sun and

  Moon have long fascinated us. This lecture describes the eclipses of

  the Sun and Moon, their types, and how often they occur.

  Recorded 2007 Oct 1 in 1000 McPherson Lab on the Columbus campus

  of The Ohio State University.

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