The History and Philosophy of Astronomy Lecture 8: Cpernicus. Presentation

Astronomy 350L (Fall 2006)

The History and Philosophy of Astronomy (Lecture 8: Copernicus)

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

Astronomy during the Renaissance (c (c.. 145 1450 0 – 16 1600 00))

• Rebi Rebirth rth of cul cultura turall activ activity ity in in Europe! Europe!

Intellectual Climate: Reformation (1517 onwards)

Martin Luther

• Res Restore tore lost lost origi original nal (pure (pure)) state state of Church Church!!

Intellectual Climate: Humanism

Pico Pi co del della la Mi Mira rand ndol ola a Erasmus of Rotterdam

• Anti-A Anti-Aristote ristotelian lian strain, desire for classi classics! cs!

Intellectual Climate: Neoplatonism

• ma math thema emati tica call ha harmo rmony ny Mars Ma rsil ilio io Fi Fici cino no

• Sun wo wors rsh hip

• Sea Search rch for underly underlying ing (mathem (mathemati atical) cal) struc structure ture of reality!

Intellectual Climate: Voyages of Discovery

Columbus (1451-1506)

Spanish and Portuguese exploration

• New sp spiri iritt of di disc scov over ery! y!

Intellectual Climate: Fall of Constantinople 1453

• Esc Escape ape of Greek Greek scho scholars lars and and texts texts to Italy Italy!!

Intellectual Climate: Invention of Printing Press

Johannes Gutenberg

• Rapi Rapid d disse dissemina mination tion of knowl knowledge edge!!

Nico Ni cola laus us Co Cope pern rnic icus us • 1473 – 154 3 • De Revolutionibus  Orbi Or bium um Co Coel eles esti tium  um  (1543, On the Revolution of the Heavenly Spheres)

• W h a t wa s h e : - first modern astronomer? - la last st an anci cien entt ast astro rono nome mer? r?

Nicola Nic olaus us Cope Copernic rnicus: us: Geog Geograph raphy y of his his Life Life

Copernicus: Studies in Italy

Bologna Padua

• Bo Bolo logn gna a and and Pa Padu dua: a: astronomy, mathematics, medicine, law • Eve Eventu ntuall ally: y: Doctora Doctorate te in church church law law (Ferrar (Ferrara) a)

Coperni Cop ernicus cus:: Canon Canon at Fro Frombor mbork k Cath Cathedr edral al

• Q: Wh What at is a can canon on? ?

Copern Cop ernicus icus:: War in in Varm Varmia ia (151 (1519-1 9-1521) 521)

• Polan Poland d vs Teut Teutonic onic Knights, Knights, Coperni Copernicus cus involved involved in defence defence

Copernicus: De Revolutionibus (1543) Revolutionibus (1543) • he helilioc ocen entr tric ic mod model el • Q: Wh What at mo moti tiva vate ted d him him? ? • Q: St Stru ruct cture ure of boo book? k? • Q: In wh whic ich h way way was was it revolutionary?

De Revolutionibus : Basic Structure • Boo Book k 1: Popular Popular justifi justificat cation ion for Earth Earth’s ’s motion motion • Boo Book k 2-6: Mathem Mathemati atical cal detai details ls to accou account nt for celestial (planetary) motions • Boo Book k 1: not not origina original, l, not not really really convi convinci ncing ng • Boo Book k 2-6: hig highly hly spe special cialize ized d (“Mathematics is for mathematicians”)

De Revolutionibus : Basic Principles (Book 1) • Sun un-c -cen ente tere red d • Ear arth th is pl plan anet et (3rd from Sun) • Earth’s motions:

- da dailily y rot rotat atio ion n - an annu nual al revo revolu lutio tion n around around Sun Sun • Ce Cele lest stia iall moti motion ons s uniform and circular • fi fini nite te un univ iver erse se

De Revolutionibus : Basic Principles (Book 1)

• da dailily y rot rotat atio ion n of of celestial (fixed star) sphere

• yea earl rly y mo moti tion on of Sun along ecliptic (zodiac)

Big Problem: Missing Stellar Parallax

• Not observ observed ed (too (too small) small) until until 1838 1838 (Bessel (Bessel)! )!

Big Problem: Missing Stellar Parallax

• Cop Coperni ernicus cus (corre (correct) ct) idea: idea: Stars Stars are are at immens immense e distance (same idea as suggested by Aristarchus) • Cop Coperni ernican can univers universe e (although (although still still finite finite)) much larger than Ptolemaic one

De Revolutionibus : Aesthetic Appeal Ptolemy

Copernicus

• Conc Conceptu eptually ally simpl simpler er explanat explanation ion for retrogr retrograde ade moti mo tion on (7 sp spher heres es vs 12 12)) • Retr Retrogra ograde de motion motion of plane planets ts natural natural outc outcome ome of Earth’s motion!

Coperni Cop ernicus cus vs Pto Ptolem lemy: y: Elong Elongatio ation n of Venus Venus

• Obs Observ ervati ational onal fact: fact: Venu Venus s and Mercur Mercury y never never stray much (in angular distance) from Sun • Q: Ho How w to to exp expla lain in? ?

Coperni Cop ernicus cus vs Pto Ptolem lemy: y: Elong Elongatio ation n of Venus Venus Ptolemy

Copernicus

Venus Earth Sun

• Cope Copernic rnican an syste system: m: Maximum Maximum elong elongatio ation n natural consequence • Pto Ptolem lemy: y: Need Need to make make ad-ho ad-hoc c assump assumption tion

De Revolutionibus : Final Result (Books 2-6) Ptolemy

Copernicus

• As messy messy as as Ptolem Ptolemy, y, not not more more accurat accurate: e: - a failure failure reall really y (accordi (according ng to origina originall claim) claim)

Principle of Perfect Uniformity • 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

• Sam Same e device device as as used used by Arabs Arabs:: Did he he know? know?

Harmony of Copernican System • No cle clearar-cu cutt proof proof poss possibl ible e for heliocentric model - actu actually: ally: prob problem lem with miss missing ing fix-star parallax

• Bu Butt Coper Coperni nicu cus s clai claims ms that that his system is more elegant (“harmonious”) than Ptolemy’s, e.g.: - retro retrogress gression ion of plane planetary tary motion - ord order erin ing g of pl plan anet ets s - max maximum imum elon elongat gation ion of of Venus Venus and and Mercury - cor correl relati ation on of oppo opposit sition ion and and brightness (Mars, Jupiter, Saturn)

De Revolutionibus : The Long Road to Publication • ap appea peared red in pri print nt 15 1543 43 - ye year ar of Co Coper perni nicu cus s deat death h • Q: Wh Why y did did it ta take ke so so long long? ? • Co Comm mmen enta tari riol olus us (b (bas asic ic idea ideas) s):: - al alre read ady y ~1 ~151 510 0 • Fi Firs rstt (hand (hand-wr -writ itten ten)) draft draft:: - al alre read ady y ~1 ~153 530 0

De Revolutionibus : Reasons for Procrastination • Cope pern rniicus was a busy man (canon, war,…) • He was was afrai afraid d of rid ridicu icule le beca because use of seemingly seemin gly countercounter-intuti intutive ve notion of Earth’s motion - att attem empt pt to per perfec fecti tioni onize ze his new sys syste tem m

• Ant Antici icipati pation on of counter counter-reac -reactio tion n from Church Church - Eart Earth’s h’s motion motion cont contradic radicted ted by Scrip Scripture ture

• Doub Doubts ts whe whether ther he got it righ right: t: - it nev never er qui quite te fit fits s

Enter Joachim Rheticus (1514-76) • pr prof ofes esso sorr of math mathem emat atic ics s in Wittenberg • vis visits its Cope Copernic rnicus us in Frau Frauenbu enburg rg • pr prod ods s Cop Copern ernic icus us to towa ward rd publication

arra rati tio o Pri rima  ma (1540, first report): • Nar - su sum mma mary ry of fu fullll De Rev.

Early Reception of De Revolutionibus 

Important Early Role of Wittenberg

Martin Luther: 1517

• Bir Birthp thplace lace of of Protes Protestan tantt Reform Reformatio ation! n!

Enter Erasmus Reinhold (1511-53) • pr prof ofes esso sorr of of ast astron ronom omy y in Wittenberg • uses De Rev. to calculate new tables of celestial motions

rute teni nic c Tab ablles (1551) • Pru widely used • In Indi direc rectt fame fame for Coper Coperni nicus cus

Copernicus fame as “Second Ptolemy”

Strasbourg Cathedral: Astronomical Clock (1574)

Copernicus: Victory by Infiltration

rute teni nic c Tab able les  s  • Pra Practi ctical cal val value ue of Rein Reinhold hold’s ’s Pru

Early Reception: Need for better calendar

(Pope Gregory XIII)

• Uses De Revolutionibus !

Copernicus: Victory by Infiltration • As Astr tron onome omers rs go gott used used to De Rev. as practical tool for predicting celestial motions • Use despite despite,, not because of, idea idea of Earth’s motion • Thus: De Rev. never went away (starting point for Kepl Ke pler er an and d Gali Galile leo) o)

• Cop Coperni ernicus cus in-bui in-built lt defence defence:: Make book book unreadab unreadable le for nonastronomers (“mathematics is for mathematicians”) Osia iande nder’s r’s • Os

intro in troduc ducti tion on:: Heliocentric hypothesis

 just convenient device of mathematical astronomy, not real!

Copernican Revolution: A New Generation • Nex Nextt generati generation on of astronom astronomers ers (Keple (Kepler, r, Galile Galileo, o, …, Newton) • Ad Addr dres ess s prob proble lems ms of of New Astronomy  (E.g., consequences of Earth’s motion…)

• Cop Coperni ernicus cus addre addresse ssed d probl problems ems of Old Astronomy  (E.g., a planetary model without equants…)

De Revolutionibus : Reaction from Church

• In Init itia ialllly: y: Very Very frie friendl ndly! y! • In pre preffac ace e of of De Rev .: .: Dedication to Pope

(Pope Paul III)

De Revolutionibus : Reaction from Church

• Req Reques uested ted to be bri brief efed ed about new Copernican theory in 1533 • Q: Ho How w cou could ld thi things ngs hav have e turned so sour a short time later???

(Pope Clement VII)

The Christian Universe: Dante’s Divine Comedy  • As Astr tron onomy omy = The Theol olog ogy y • Ce Centr ntral al Ea Earth rth bec becom omes es essential ingredient of Christian Theology

The Copernican Revolution as Paradigm Shift 1. “Normal” science 2. Anomalies, conflicts 3. New framework (paradigm) 4. “Normal” science 5.

…

Thomas Kuhn (1922-96)

• The Structure of Scientific Revolutions (1962)

Freud’s Three Demotions of Humanity •

Copernicus: - ma manki nkind nd not not speci special al in spac space e

•

Darwin: - man mankind kind not spe specially cially desi designed gned

• Freud: - hu human man min mind d (“eg (“ego”) o”) not fully in charge, influence from subconscious (“id”) Sigmund Freud (1856-1939)

• in Introductory Lectures into Psychoanalysis (1917)

Copernicus and the Invention of Nihilism

Copernicus and the Invention of Nihilism • Nietzsche blames Copernicus and modern science for spiritual erosion and cosmic forlornness

• “Since Copernicus, humanity is rolling from the center into nothingness…”

Friedrich Nietzsche (1844-1900)

Copernicus • De Revolutionibus: Not a revolutionary book, but a revolution-making one! • Slo Slow, w, but inexo inexorabl rable e ascendan ascendancy cy of Copern Copernica ican n system - init initially ially base based d on prac practica ticall utility utility - Ear Earth th’s ’s motio motion n largely largely ignor ignored ed - pro provides vides star starting ting point point for for New Astro Astronom nomy y (Kepler…) - som some e advantag advantages es in (Neopla (Neoplatonic tonic)) elegance elegance

• Gre Great at strugg struggle le with with Church Church slowly slowly emerg emerging ing • Aft After er Copernic Copernicus: us: Humanki Humankind nd enters enters modernit modernity y