The History and Philosophy of Astronomy Lecture 6: Middle Ages. Islam. Presentation

Astronomy 350L (Fall 2006)

The History and Philosophy of Astronomy (Lecture 6: Middle Ages/Islam I)

Instructor: Volker Bromm TA: Jarrett Johnson The University of Texas at Austin

Medieva Med ievall Ast Astron ronomy omy and Cosm Cosmolo ology gy

• Mid Middle dle Age Ages/I s/Isla slam m I (Se (Sep. p. 19) - Decl Decline ine of Western Western (Medite (Mediterran rranean) ean) Civiliza Civilization tion (“Dark Ages”): Ages”): 500 500 – 1000 AD AD - Early Middle Ages (“Dark (800 00 – 14 1400 00 AD AD)) - Asce Ascendan ndancy cy of of Islam Islamic ic Astr Astronom onomy y (8 - Preservation and transformation of ancient knowledge

• Mid Middle dle Age Ages/I s/Isla slam m II II (Sep (Sep.. 21) 21) - Reco Recovery very of Europe European an Civili Civilizatio zation n and Late Late Middle Middle Ages (c. 1000 1000 – 1450 AD) AD) - High and - Sett Setting ing the the Stage for for the Coperni Copernican can Revolut Revolution ion - Recasting of the Ancient Tradition

The Fall of Rome

• “Ba “Barb rbari arian ans” s” (G (Germ erman anic ic tr trib ibes es/Hu /Huns ns)) at th the e gat gate e

The Fall of Rome

• “Ba “Barb rbari arian ans” s” (G (Germ erman anic ic tr trib ibes es/Hu /Huns ns)) at th the e gat gate e

The Fall of Rome Q: Why did it happen? • Gibbon’s Decline and Fall of the  Roman Empire:  - decadent -  decadent society - ec econ onomi omica call pre press ssur ure e - co cons nstan tantt thre threat at of inv invas asion ion - co corr rrup uptt gove govern rnme ment nt (Edward Gibbon, 1737-94)

The European Dark Ages • Ear Early ly Christi Christianit anity y initial initially ly hostile hostile toward toward pagan learning, especially astronomy/astrology • Los Loss s of libr librarie aries s and anc ancient ient tex texts ts • Gre Greek ek langu language age was was large largely ly forgo forgotte tten n only simplified Latin • Life was brutish brutish and short, short, primiti primitive ve economic economic level • a tremendou tremendous s decline decline in cultur cultural al sophist sophistica ication tion

A Rescue Attempt: Boethius (480-524 AD) • “T “The he La Last st Ro Roma man” n” • Co Cour urtt off offic icia iall und under er Theoderic, King of the Ostr Os trog ogot oths hs (r (rul uler er of post-Roman Italy) • ex exec ecut uted ed fo forr tr treas eason on • The Consolation of Philosophy 

A Rescue Attempt: Boethius (480-524 AD) • His (hy (hyperper-ambi ambitio tious) us) progr program: am:

Greek Aristotle Plato

translate

Latin Logical works

• ran out out of time: time: most most text texts s lost lost for Latin Latin West West!! • onl only y rescue rescued d Plato Plato tex text: t: Tima Timaeus eus (trans. Calcidius) • (Greek) works of astronomy forgotten for centuries!

Kosma Ko smas s Indiko Indikopl pleu euste stes s (6th cent. AD)

• Rep Repudiat udiating ing the the idea idea that Earth Earth is is a Sphere! Sphere!

Kosma Ko smas s Indiko Indikopl pleu euste stes s (6th cent. AD)

• Un Univ ivers erse e is is tab tabern ernac acle le!! • Ver Very y low low standa standard rd of secul secular ar learni learning! ng! • ReRe-acce accept pt spheric spherical al Earth Earth only only 500 years years later! later!

The Ascendancy of Medieval Islam

• Eme Emergen rgence ce of vibran vibrantt and tolerant tolerant civil civiliza ization tion!!

Islam: The Need for Astronomy • re reliligi gious ous req requir uireme ement nts: s: - predict beginning of month - alti altitude tude of Sun Sun (hours (hours of prayer prayer))

• es esta tabl blis ish h offi office ce of of muwaqqit  (mosque timekeeper)

Astronomers respected position in society!

The House of Wisdom in Baghdad

(9th cent. AD)

• Vigo Vigorous rous effort effort to transla translate te Greek Greek texts into into Arabic Arabic - Ca Caliliph ph alal-Ma Mamu mun n (A (Abb bbas asid id dyn dynas asty ty,, 750 750 – 12 1258 58)) • Translating Ptolemy:

Greek: Syntaxis

Arabic: Almagest

Ptolemaic System within Islamic Astronomy • No fun fundame damental ntal mod modifi ificati cation on to Aristotelian-Ptolemaic cosmology! • Im Impr prov oveme ement nts s in prec precis ision ion - bui buildi lding ng of of majo majorr observ observato atories ries!! - imp improv roved ed mat mathema hematic tical al meth methods ods!! • Dis Discus cussion sion of doubt doubts s about about Ptol Ptolemy! emy! Almagest

Precision Astronomy: Great Observatories Ulugh Beg (d. 1449)

- Grandson of Tamerlane

Samarkand

- Gr Grea eatt mura murall sext sextan antt

Ulu lug gh Be Beg g’s Sta tarr Ca Cata talo logu gue e • fi firs rstt majo majorr new new cata catalog logue ue of stars since time of Hipparchus (2nd cent. BC) • high-precision (> 1000 stars) • unknown in Europe

The Astrolabe: Universal Astro-calculator • in inve vente nted d by Gr Greek eeks, s, bu butt perfected by Arabs • measure altitude (height)

of stars (or Sun) • predict position of

star st ars/ s/Su Sun n at given given tim time e

Critiquing Ptolemy • Averroes (1126-98 AD) • lived in Moorish Andalusia • “The Commentator”

of Aristotle • ph philo iloso sophi phica call pu puris rist: t: found contrived model of Ptolemy (deviation from uniform spherical motion) inelegant

Critiquing Ptolemy • Nasir al-Din al-Tusi (1201-74 AD) • lived in Persia • adviser to Mongol

conq co nque uero rorr Hulag Hulagu u Kh Khan an • on one e of grea greate test st astro astrono nomer mers s during Islamic Period

Al-Tu AlTusi’ si’s s Obs Observ ervato atory ry at at Marag Maragha ha

• 12 years years of inten intense se effort: effort: Planet Planetary ary Tables Tables (“zij”) (“zij”)

Al-T Al -Tus usi’ i’s s At Attac tack k on Ptole Ptolemy my • el elim imin inate ate un un-Pl -Plato atoni nic c equan equantt wi with th doub double le epic epicyc ycle! le! equant

double-epicycle

• Cope Copernic rnicus us did the the same: same: Did Did he know know of al-Tus al-Tusi? i?

Legacy of Islamic Astronomy • Pres Preserve erved d ancient ancient Greek Greek astronom astronomy y / philosoph philosophy y • Imp Improv roved ed math mathemat ematica icall meth methods ods • Dil Diligen igentt observer observers s (astrono (astronomic mical al tables tables)) • Att Attitu itude de toward towards s Ptolema Ptolemaic ic Framew Framework ork:: - no fu funda ndamen mental tal cha change nge!! - imp improve roved d precision precision (Great (Great Observ Observato atories ries)) - ra rais isin ing g of of dou doubt bts s - elim eliminati ination on of Ptole Ptolemaic maic equan equantt