PHY1033C/HIS3931/IDH 3931 : Discovering Physics: The Universe and Humanity’s Place in It

Fall 2015

Prof. Peter Hirschfeld, Physics

Announcements

• HW 2 due Sept. 22 (use Almagest passage in syllabus)

• Lab 2 today 2nd hour • Reading: Gregory, Chapter 3, pp. 45-51 • http://www1.umn.edu/ships/galileo/library/c

usa3.pdf Sections 156-166 (pp.89-95) (tough!) • Osiander’s foreword and Copernicus’ preface

Last time

• Concept of acceleration (see slides on web) • Mathematical contributions of Mertonian/Parisian scholar • Exploration of the globe: from Ptolemy to da Gama

Clicker quickies acceleration is defined to be

a. the rate of change of the position of an object b. the rate of change of velocity of an object c. the speed of an object multiplied by time d. the speed of an object divided by distance e. the displacement of an object divided by time

Clicker quickies Reading: Wertheim discusses the “mathematical harmonies”

of the Pythagoreans, which they thought were related to a. the ratios of the sizes of planetary orbits b. The ratios of the frequencies of musical notes c. the ratios of the speeds of the planets d. natural mathematical affinities of the soul e. all of the above

Expansion of humanity’s understanding of the globe, cont’d

• da Gama has shown you can go around Africa to get to India • One would like to go further, to China and the spice Islands

(Moluccas), but it’s far • Can you go west and get to India/China?

Cristobal Colon (Christopher Columbus) sometimes called the world’s greatest politician: • When he left, he didn’t know where he was going • When he arrived, he didn’t know where he was • He messed up the lives of everyone he encountered • Did it all on someone else’s money

Now that India had been reached by sea, was there another route to the East?

Columbus had studied Ptolemy’s Geography and Marco Polo’s Travels Distance from Africa to China not great Read Paolo Toscanelli –

distance = 5000 miles Reduced distance to 3500 miles Began trying to persuade Portuguese in 1480s

After rejection, turned to Spain

Left for Canary Islands August, 1492 Used dead reckoning, not celestial navigation

Gold ornaments the of inhabitants of the islands convinced him he had reached islands off China

Columbus underreported the distances he calculated to the crew

Others became convinced that what Columbus had revealed was a new world

One who used these words was the Italian geographer Amerigo Vespucci Inspired by the voyages of Columbus, he visited the Gulf and the eastern coast of the U.S. in a voyage of 1497

Other voyages to the east coast of South America convinced him that this territory represented a new continent

World map of 1507 Martin Waldseemüller

The world at the beginning of the 16th century was a different place from what it had been

The goals were the same as they had been in the East – spices, gold, and Christians

Ironically as the world became new, Europeans looked backwards to regain lost wisdom In the process they stumbled upon a new vision of the cosmos Before Copernicus there was another world shaking event

Ferdinand Magellan

From the lesser Portuguese nobility In 1505 he signed on at 24 to a 20-ship fleet the king commissioned to take over spice trade

Expected resistance from the Sultan of Egypt and the Indian rajahs

(~1480-1521)

Cannanore

Malacca

Magellan was promoted for his actions in these campaigns Back in Portugal he fell out of favor at court Was not able to persuade the king to search for shorter route to the Spice Islands Frustrated by the rejections, he turned to the king of Spain

18-year old Emperor Charles I found the idea intriguing But after being disappointed with Columbus, the king’s advisors were against it He also reported a geographer’s conclusion about the Treaty of Tordesailles Magellan claimed to have learned about the existence of a pass from a document in the Portuguese archives

A fleet of 5 ships set off September 20, 1519 with Magellan in command Other 4 ships had Spanish captains who did not trust the Portuguese admiral The first location of the supposed pass was just the mouth of a wide river Magellan pushed farther and farther south – he was caught in a bind But the farther south he went, the more his hopes waned

Three ships arrived in the Philippines in the spring of 1521

He knew he could not be far from the Spice Islands

Magellan determined to take the land for Spain

When the Victoria stumbled into port in Spain there were but 18 crew left Since those left behind in Malacca were later captured these were the only survivors of the original 265 Then cargo of spices did pay for the voyage

Ecclesiastical debate about humanity’s central position in cosmos

…or, do extraterrestrials exist?

Lucretius (99-55 B.C.E.) Roman poet, philosopher De rerum natura

“It is in the highest degree unlikely that this earth and sky are the only ones to have been created.”

from the collision of accidental, random, and purposeless atoms, producing the earth, sea, sky, and the races of living creatures. (from Epicurus 341-270 BCE)

For Lucretius the world resulted

Thomas Aquinas Italian, 1224-1275

But God could have made many worlds

Nevertheless Thomas was misunderstood and Proposition 34 of the Condemnations of 1277 referred to his teachings: one could not advocate “That the First Cause cannot make other worlds.”

Aristotelian idea of “natural place” implies one must reject plurality of worlds

Singularity of life here does not impugn God’s omnipotence

Content of condemnations of 1277 – directed at U. Paris

9. "That there was no first man, nor will there be a last; on the contrary, there always was and always will be generation of man from man.“

34. “That the First Cause cannot make other worlds” 49. "That God could not move the heavens with rectilinear motion; and the reason is that a vacuum would remain.“

87. "That the world is eternal as to all the species contained in it; and that time is eternal, as are motion, matter, agent, and recipient”

Edict of Pope John XXI condemned the propagation of Aristotelian “errors”, e.g.

Plurality of worlds Earth the only world

Condemnations of 1277

Before 1277 Epicurean plurality of worlds rejected by Christian theologians

After 1277 Two possibilities emerge for Christian theology

Nicholas of Cusa (1401-1464)

“Life, as it exists on earth in the form of men, animals and plants, is to be found, let us suppose, in a higher form in the solar and stellar regions. Rather than think that so many stars and parts of the heavens are uninhabited and that this earth of ours alone is peopled - and that with beings, perhaps of an inferior type - we will suppose that in every region there are inhabitants, differing in nature by rank and all owing their origin to God, who is the centre and circumference of all stellar regions.”

From On Learned Ignorance, 1440 +

“If it be inquired whether men exist on that [other] world, and whether they have sinned as Adam sinned, I answer no, for they would not exist in sin and did not spring from Adam . . . . As to the question whether Christ by dying on this earth could redeem the inhabitants of another world, I answer that he is able to do this even if the worlds were infinite, but it would not be fitting for Him to go unto another world that he must die again.”

William Vorilong, French 1390 – 1463 +

Johannes Kepler “The earth is home of the special creature and for his sake the universe and world have been made.” from The Epitome of Copernican Astronomy, Bks IV-V, 1620-21

“If there are globes in the heaven similar to our earth, do we vie with them over who occupies a better portion of the universe? For if their globes are nobler, we are not the noblest of rational creatures. Then how can all things be made for man’s sake?” from Kepler’s Conversation with Galileo’s Sidereal Messenger,1610

Rene Descartes

“I do not see at all that the mystery of the Incarnation, and all the other advantages that God has brought forth for man, obstruct him from having brought forth an infinity of other very great advantages for an infinity of other creatures.”

Letter to Chanut, 1647 +

Was not automatically saying that this had occurred, only that it might have.

Fixed stars may be centers of other systems like ours. General Scholium, Opticks

“If all places to which we have access are filled with living creatures, why should all these immense spaces of the heavens above the clouds be incapable of inhabitants?”

+

Population Mercury 8,960,000,000 Venus 53,500,000,000 Mars 15,500,000,000 Vesta 64,000,000 Juno 1,786,000,000 Ceres 2,319,962,400 Pallas 4,000,000,000 Jupiter 6,967,520,000,000 Saturn 5,488,000,000,000 Saturn's outer ring Inner ring 8,141,963,826,080 Edges of the rings Uranus 1,077,568,800,000 The Moon 4,200,000,000 Jupiter's satellites 26,673,000,000 Saturn's satellites 55,417,824,000 Uranus's satellites 47,500,992,000 Total 21,891,974,404,480

Thomas Dick, Celestial Scenery, 1837 NB population of Earth in 1840 was 1,000,000,000

Question for discussion: Did the Church’s suppression of Aristotle’s teachings help or hurt the progress of science?