Astronomy 161 - Introduction to Solar System Astronomy episodes:

• October 13, 2006Lecture 17: On the Shoulders of Giants: Isaac Newton and the Laws of Motion

  The work of Copernicus, Kepler, and Galileo all contributed to a new way

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

  move that way. Enter Isaac Newton, who within a few years swept away

  the last vestiges of the Aristotelian view of the world and replaced

  with a new, powerfully 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. We are now ready, next week, to examine the role of

  Gravity and finally explain the orbits of the planets. Recorded 2006

  Oct 13 in 100 Stillman Hall on the Columbus campus of The Ohio State

  University.

  ...more

  

  ---

• October 12, 2006Lecture 16: Galileo and the Telescope

  Tycho did as much as 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 his discoveries with the

  telescope. These observations were to electify Europe in the early 17th

  century, and begin the final intellectual 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 2006 Oct 12 in

  100 Stillman Hall on the Columbus campus of The Ohio State University.

  ...more

  

  ---

• October 11, 2006Lecture 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, the

  brilliant Danish astronomer whose precise measurements of the planets

  represented the highest expression of pre-telescope astronomy, and

  Johannes Kepler, the brilliant and tormented German mathematician who

  used Tycho's data to derive his three laws of planetary motion. These

  laws were to sweep away the vast complex machinery of epicycles, and

  provide a geometric description of planetary motions that set the stage

  for their eventual physical explanation by Isaac Newton a generation

  later. Recorded 2006 Oct 11 in 100 Stillman Hall on the Columbus campus

  of The Ohio State University.

  ...more

  

  ---

• October 10, 2006Lecture 14: The Revolutions of Nicolaus Copernicus

  In 1543, Nicolaus Copernicus re-introduced the Heliocentric idea of

  Aristarchus of Samos in an attempt to purge Ptolemy's geocentric system

  of the un-Aristotelian idea of the Equant. His goal was to derive a

  model that, in his words, pleased the mind as well as preserved

  appearances. What he started, without intending, was a profound

  revolution in thought that was to overturn both Ptolemy and Aristotle

  within two centuries, and help give birth the the modern world. This

  lecture looks at the Copernican system, and sets the stage for the

  scientific revolution of the following generations. Recorded 2006 Oct

  10 in 100 Stillman Hall on the Columbus campus of The Ohio State

  University.

  ...more

  

  ---

• October 09, 2006Lecture 13: 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 2006 Oct 9 in 100 Stillman Hall on the Columbus campus

  of The Ohio State University.

  ...more

  

  ---

• October 05, 2006Lecture 12: The Wanderers - Planetary Motions

  How do the planets move across the sky? This lecture will review

  planetary motions, specifically the apparent motions of the five

  classical planets (Mercury, Venus, Mars, Jupiter, and Saturn) as seen

  from the Earth. We will discuss the classical division of the

  naked-eye planets into inferior (Mercury and Venus) and superior

  (Mars, Jupiter, and Saturn) planets, and describe their main configurations

  in the sky: conjunction, opposition, maximum elongation, and quadrature.

  We will then discuss retrograde motion, the apparent westward reversal of

  motion seen at opposition in the superior planets and inferior conjunction in

  inferior planets. The quest to describe the very complex motions of the

  planets marks the birth of science, and will be the central theme of next

  week's lectures. Recorded 2006 Oct 5 in 100 Stillman Hall on the

  Columbus campus of The Ohio State University.

  ...more

  

  ---

• October 04, 2006Lecture 11: The Calendar

  Why are there leap years? This lecture explores the astronomical

  origins of the calendar. We will discuss lunar and solar calendars and

  their hybrids in history and tradition (for example, the Islamic Lunar

  Calendar and the Jewish Luni-Solar Calendar), and the Julian and

  Gregorian Calendar reforms. Recorded 2006 Oct 4 in 100 Stillman Hall on

  the Columbus campus of The Ohio State University.

  ...more

  

  ---

• October 03, 2006Lecture 10: Telling Time

  What time is it? This lecture is the first part of a two-part

  exploration of the astronomical origins of our time-keeping and calendar

  conventions. Today we will discuss the division of the year into

  seasons by the motions of the Sun, and the oft-forgotten origins of our

  holidays in in the solar Quarter and Cross-Quarter days, the division of

  the year into 12 months based approximately on the cycle of lunar

  phases, the traditional division of the month into weeks reflecting the

  seven moving celestial bodies, and the division of the day into hours,

  minutes, and seconds. We will also discuss the difference between the

  Solar and Sidereal days, and the introduction of timezones used in modern

  civil timekeeping. Recorded 2006 Oct 3 in 100 Stillman Hall on the

  Columbus campus of The Ohio State University.

  ...more

  

  ---

• October 02, 2006Lecture 9: Eclipses of the Sun and Moon

  Eclipses of the Sun and Moon are among the most glorious spectacles in

  the sky. This lectures looks at the causes and types of eclipses, and

  how often they occur. Recorded 2006 Oct 2 in 100 Stillman Hall on the

  Columbus campus of The Ohio State University.

  ...more

  

  ---

• September 29, 2006Lecture 8: Phases of the Moon

  How does the Moon appear to move through the night sky? This lecture

  introduces the Moon, and describes the monthly cycle of phases. Topics

  include synchronous rotation, apogee and perigee, the cycle of phases,

  and the sidereal and synodic month. Recorded 2006 Sep 29 in 100

  Stillman Hall on the Columbus campus of The Ohio State University.

  ...more

  

  ---