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Halley hollow

first prpposed in 1692

based pn thje lunar density by Isaac Newton

1st ed Principia (1687): mass of the moon to the earth 1:26 relative densities 9 to 5

"sir isaac newton has demonstrated our moon to be more solid than our earth, at 9 to 5. Why then may we not suppose 4 ninthjs f our earth to be cavity"

It was the first deduction ever drawn from Newton's Principia

Newton had constrained the density of the sun to a quarter that of the earth, and by examining their relative effects on the tides, determined the Moon's density.

By the third edition Newton had corrected it to 39.788

drawing on tidal data from plymoth and the bristol channel

this method is valid and was actually used by astronomers in the 18th century

the tide is affected by local geography

Halley considered Newton's determination of the moon's density the finest calculation in the principia

By 1683 Halley had concluded that the Earth had four magnetic poles two in the southern ocean one in sptizbergen and one in the bering strait

motion of lines of magnetic declination by a few minutes of arc each year

halley had concluded at st helena that it could not be due to iron deposits

within the earth, there lay another concentric sphere, with its own magnetic poles

the outer pair stationary, the inner sphere revolving

three concentric circles, of a proportion of venus, mars and mercury, held in place by gravity and held up by magnetic matter in their crusts

trial

the declaration made by the Holy Father and published by the Sacred Congregation of the Index has been notified to him, wherein it is set forth that the doctrine attributed to Copernicus, that the Earth moves around the Sun, and that the Sun is stationary in the centre of the world and does not move from east to west, is contrary to the Holy Scriptures and therefore cannot be defended or held.

father fra raffaello visconti reviewed the dialogue and stamped approved for publication.

Much to Galileo's disgust, the manuscript underwent several corrections by the inquisition, including the addition of a preface

"we thinjk that galileo may have overstepped his instruction s by asserting absolutely the earth's motion and the sun's immobility and thus deviating from hypothesis; tht he may have wrongly attributed the existing ebb and floe of the sea to the nonexistent immobility of the suna dn motiokn of the earth.

5 sep 1632 urban exploded into a rage at galileo, claiming that he had deceived him campoli had told hhim that galileo was ready to do everything urban ordered

i did not believer his holiness would bbring about the prohibition of the already approved book without at least heraing mr galilei fiorst hjis hiolines answered that that was the least ill which could be done to him and that he shoudl tk=e care not to be suimmed byt the holy office, that he ahs appointed a commission of thelogiansm and other persons versed in varius sciences, serieosu and of holy mind, who are weighing every minutia word for wrod, since one is dealign witht he [ msot perverse subject one could ever come across.

the pope belioeves that the faith is facign mahny dangers and that we are not dealing with mathematical subhects here but with holy scripture religion and faith

the author[s opinion is not onlyy mentioned in it but in many places oopenly declared in an inadmissable manner, som uch so that everyione wonders how they let it be printed

his highnsess should put aside all resopet and affection tword his mathematciaian d and be blac go ongribugte hinmself to shielding catholicism from danger

"enough enough"

13 nov his holiness answered that he could come slowly in a litter with all comfrots, for indeed it was necessary to examine him personally, and that god would hopefully forgive his error of having gotten involved in an intrigue like this after his holiness himself when he was cardinal had had deliverd him from it.

he had never reciecved word that the book was printed

master of the sacred palace was targeted for allowing the book to be printed

feb 1633, galileo had been told not to talk to anyone for fear of prejudicing his case, and so remained in seclusion

"not hold or defend it" (not teach in anyway whatever) "struck me as new and unheard"

galileo confessed and abjured heresy by his own hand

high spirits wise judgemeng singular favour apartment his highness

he again said that he does not therink there is anyty way out and may god forgive mr galilei for ahving meddled with the se subjects .. mr aglileo ad been his friend, they ahd cojvered and dined secver times together familiarly and he was sorry to ahve to displease him but one was dealing with the interest of the faith and religion

"i show the contrary opinion and show that copernicuss reasons are invalid and inconclusive"

melchior incofer showed that galileo taught, defended and held copernican beliefs and expressed them in a non0-hypothetical manner in the book

ridiculing those who take the common scriptural interpretation that the sun moves as small minded

claiming that various unexplained phenomena such as the tides tetrrestrail magnetsim are teaching

inchofer argued that galileo's rationale was false, as no foreigners had written against catholic mathematicians

if he wanted to challenge foreigners, why write in italian instead of latin?

"entice the view of the coomon people in whom erros ery easily take root"

zacaria pasqualigo, "although galileo at the beginning of his book claims to want to deal with the earth's motion as a hypothjesis, in the course of his dialogue he puts the hypothesis aside, using unconditional arguments

galileo had not looked at the dialoge for three years

i freely confess that it appeared to me in several places to be written in such a way that a reader, not aware of my ubntention woudl ahve reason to form toe opinion that the gurments for the false sice whcih i intend to confute, were so stated aw to be capable of concinging because of theri strengthn rather than being easy to answer

his book was banned, ga;ileo was sentenced to imprisonment and iordered to recite seven penitential psalms once a week for the next three years

Finoccario

1632: catholic king of spain and holy roman emperor losing to protestant king of sweden

spanish: accused Urban of not supporting militarily or declaring a crusade

tuscany was allied with spain, and Urban was pissed at spain

the purpose of the dialogue, according to the preface (censors) was to show Protestants that catholics were not ignorant of the scientific issues, but made their choice on faith. (letter to ignoli)

while the arguments appeared to favour a geokenetic theoryu they were inconclusive (preface)

lgalileo received permission to publish from the authorities in rome

galileo ostensibly portrayed both sides, but copernicanism was clearly the favourite

with bellarmine dead there was no one to clarify the missif

three docors had written he was too ill to travel, 68 and chrinically ill, this was true

December 1632: if galileo did not come to rome, he woudl be taken there in chains

galileo wrote his last will and testament, and left

20 jan 1633 when first arriving in rome, he was placed under informal house arrest at the villa medici

12 April first interrogation: warning by bellarmine that the copernican theory could only be discussed hypothetically

he had not recieved an injunction to not discuss it in any way whatsoever

why had he not obtained permission to write the book in the first place, or mentioned bellarmines warning when requesting permission to publish? these made urban fell betrayed

galileo argued that he had shown that the argumetns were not conclusive and so the warning was not violated

After three weeks, duiring which galileo stayed the prosecutors apartment

eventually they worked out a plea deal: galileo would not be charged with the greater crime of violatin his injunction if he accepted the lesser charge of inadvertently transgressed the order not to defend copernicanism

galileo was orderted to be interrogated under threat of torture to ensure his intent

even if his intent was pure, said urban, he wwould be made to abjure heresy and hsi book would be banned

vehemently uspected of heresy-

letter to francesco ignoli of ravenna

not responded for eight years

guidice

in the dialogue, galileo reinterprets platos creation myth in the timaeus

each planet fell until the divine architect turned their straight motion into circular motion- law of fall

Heresy

Cardinal Cesare Baronio: bible teaches how to go to heaven, not how heaven goes

Copernicanuism was becoming widespread among both educators and clergy

if the purpose of the bible was to teach astronomy, why did it not mention any of the planets

november 1618 comets

1619: Marina gamba ded. June, cosmo recocognizes vincenzsio (11) as legitimate

1620 mother dies

1621: Gregorty 15 becomess pope

1621, coaimo dies. his son, 10, becomes grand duke

1622: Cardinal Maffeo Barberini, whio had suported galileo in the past, becomes pope

Assayer his work on comets

He and the pope met 5 times, and the pope agreed that the idea of copernicanism could be taught if it was expressdd only as an idea, rather thn truth

Letter to Ignoli, expamded onto the dialoguie concerning the two chief world systems

1629 30 years war sister in law and eight children fleeing, more mouths to feed age 63. 1631

Then plague takes his brother michelangelo

1629: Went to rome to guide the approval process

dialogue published in 1632, sold out

Pope urban in tropuble; taking sides in the catholic fight for the throne of the holy roman empire, using his position to enrich his family

he likely never read the dialogue, but others did, he felt betrayed.

1632, galileo summpned before the inquisition

12 April 1633: Galileo goes on trial, experts claiemd that thje dialoguie did supoprt copernicus

but the chuirch had allowed it to be published

After three weeks in a dungeon, galielo was asked to abjure copernicansim. He made a statemetn claiming he had accidentally claimed it to be correct

on the 22nd June 1633 he was sentenced to life imprisonment

Galileos sentence was softented to house arrest and he was allowed to stay at the home of the archbishop of sienna

the dialogue ex0ploded on the black market, not un-banned by vatican until 1822

he writes the two new sciences

1633: allowed to return home

march 1634: maria celeste dies of dystenery,

1638: Dioalgogue finally publiashed in the protestyant netherlands, but galileo coudl not read it, he was almsot blind

The first scientist to instists tha there had to be evidence for an idea before it could be cosnduiered true (dubious)

the catholic heirarchy, until 1616, encouraghed disucssion of heliocentrism as long as it applied only to scientific rather than theological matters

"one may write freely as long as on keeps out of the sacristy" cardinal dinito galileo in 1615

"he was utterly devoid of any mystical ciontemplative leanings, in which the biter passions could from time to time be resolved; eh was unab;e to transcend himself and find refugue, as ie-ler did inhs darkeshours in the cosnmic mystery. Gallileo was whooly and frightening,lly modern"

fifrst mention of a mechanistic universe (?)

"grienberger, succeeding clavius at the collego romano "if galileo had not incurred the displeasure of the company, he could have gon one writign freely abiout the motion of the earth to the end fo his days"

1623 maffeo barberini elected in 1623

baberini had intervined in favour of galilio in 1616 and written a poem about him in 1616

galieo came to rome in spring of 1624 and was showered with gifts, including a pension for his son, a precious painting and a gold and silver medal. He had six long audiences with urban

galileo could write anything he wanted about copernicus, provided he spoke only hypothetically; the decree of 1616 was not revoked

just because the idea explains certain phenomena, that does not mmean it is true for god is all powerful and could have produiced the phenomena through entirely diffent means

january 1630 the dialogue was completed

"from a most eminent and learned person and before whom one must fall silent" "this admirable and angelic doctirne"

two world systems

first day, refute aristotle

second day relativity of motion and the ships mast argument

he believed that fre falling bodies described a circular path, rejected kepler's laws

galileo claimed falsley that copernicus didn't need eipcycles

lie to children

saves phenona rather than true

refuses to acknowledge the tychonic system

if the sun travels around the earth th spots will look the same only if then also assuime that the suns axis always remains parallel to itself, and this he finds very hard and almost inmpossible to believe

yet this is what the earth does; its axis remains parallel to itself at 23 1/2 degrees

thanks to plague breaking out in rome, and his connection to the royal court of tuscany, galileo manmaged to get the book published before the roman censors could read it

at trial, galileo dened the strongly worded injunction and produceed ballormines certificate

the inquisition showed through a long lsit of quotations that galileo had not only discussd copernicus, he ahd taught defended and held it and called thsoe who did not share it mental pygmies, dumb idiots, adn hardly deserving to be called human beings

“Man cannot presume to know how the world really is, since God could have brought about the same effects in ways unimagined by humans. It is not proper to restrict God’s omnipotence”

being a good catholic did not mean exemplary, it was more in the mafia sense of "a friend of ours"

scripture claimed the heavens were corruptible, not that the earth moved

"this sort of person thinks that philosophy is a book like the aneneid or the odyssey truths are to be sought mot in the world or in nature but to use their words by comparing texts

the discovery that the planets were opaque and reflected sunlight surprised even kepler

"Did castelli not know that the demonstrations produced earlier were sufficient to convince those who can reason and want to know the truth but that to convince those who are obstinate and care only for empty applause of the stupid mob the witness of the stars come down to earth to speak for themselves woudl nto sduffice?

bellarmine answered that the bible was revealed throgyuh teh holy spirit, and is innerant, though alowing for reconsideration should conclusive proof be found

galileo responded that thsoe who had accepted copernicanism did so against their own initial beliefs in its absurdity and so had considered all sides, and so thier opinoons were more valid than those who simply read data unintelligently.

galileo poointed out that copernicus had never treated his idea as a hypothesis- the idea that he did came ffrrom the preface written by osiander

galileo countered that the church fathers never discussed the mobiity of the earht adequately and in any case the counicl of trent wasa reposnes to protestantism

"our writes knew othe truth about the form of the heacvens but the holy spirit who was speaking througnh them did not wish to teach men wthose things that are useful to nmo one for salvation"

galileo believed he was more faithful to aristotle than his followers because aristotle based his beliefs on sensory experience, rather than simply quoting others books.

Venus and mercury were never far from the sun; the superior planets epicycle motions were always parallel to the sun's orbit around the earth. These were mere facts to potelmaics , but to copernicans they were explained by heliocentrism

ere, 1613, inhis responst to scheiner provided his fifrrst work on the principle of inertia and also ghis first open defense of coperinicanuism

evenm tje fuitire urban viii expressed admioration fofr the publication

galileo is shifting the burden of oproof onto hsi accusers becaus he cannot provide conclusive proof of copernicanism becauee, frankly, it does not exist

galileo does nto proide any evidence in supprot of copernicanism, only suggests it is proven beyond doubt

galileo knew that if the earth were stopped, the entire woprld would be anhillated

the bishop of fiesole demanded coperniucs be jailed, only to learnhed been dead for 70 years

Galileo later claimed that as copernicus's book wa accepted by the chuch it could not be heretical, though this is only as spoken of hypothetically

the initial decree was opnly made publlic in 1633, during galilos final confrontation

The jesuits had converted tothe tychonic system

Ueban the VIII wazs interested in science, and a friend of galileo- he had demonstrated his telescope to him and had sided with hin in a debate about floating bodies, and even wrote a poen m for him galileo's glass

"philosophy is written in the grand book of the universe, which stands continually open to our gaze. But the book cannot be understood unless one first learns to comperehend teh language and to read the alphabet of which it is composed. It is written in the language of mathematics, and its characters are triangles, circles and other geometric figures, without which it is humanly impossible to understand a single word of it. Without these, one wanders about in a dark labyrinth."

as if the book of the uinivere ha been written to be read only by aristotle and his eyes had been destined to see for all posterity

koestler

two new scineces were materials mechanics (strength) and kinematics

steele

criticised orazio grassi over his opinions of comets

the arguiment in the dialoge was won by the coperinican supoporter

the thirty years war was causing catholics to go on the defensive

galileo arguied that the book showed both sides of the argumetn fairly

mctavish

Gallileo visited pope paul and cardinal barberini, and considered both a success

galileo's letters refuting scheiner were presented as evidence for his copernicanism

galileo's enemies placed a forged docuiment in the vatican records saying that he had been ordered to neither hold nor defend Copernicanism, nor to teach it in any way

discourse on comets

tthe assayer also poked fun at hjessuits who were far from pleased

the dialogue was written in italian rather than latin

balanced account of the two systems and not come out in favour of the heliocentric view

the aristotelian was called simpliciius, the salviati, simpl;cius was portrayed as a fool

his enemies suggested simplicius was the pope, naturallyy rbain was furious

because ballarmine was dead, he could not challenge the forged document

veolocity time distance sqwuared

discourses was pubhlished in the netherlands (discourses and mathematical demonstrations converning the two new sciences

with his new forumale, galileo was able to show that canonballs moved ina aparabopla

drake

three of the ten cardinals refused to sign his sentence

modern sciience was the fusion of useful science (techne) with pure science (episteme)

aristotle natural place

galileo believed that a perfect understanding of nature was impossible, but that human intellect had perfectly understood some things, such as mathematical proofs, science posed no threat to philosophy and could only improve

mathematics was neither an abstract persuit nor alien to physics, but a part of physics. if math did not agree with results, then something has been left out

the essences of things cannot be known, science is concerned with properties and observations

galileo did not want the church to adopt copernicanism, what he wanted was for the church to not stifle debate on issues that could be resoloved without scripture

on the matter of introducing novelties, does anoyone doubt that in wanting minds created free by god to make tehmsleves slaves of others will, most serious scandals will be born? and wanting people to deny their own senses and suibject them to teh rule of another, and allowing persons entirely ignroant of a science as judges over those knowing it, so that by the authority conceded to them they are empowered to have things their way, these are novelties capble of ruiining repyublics and destroying states

the conesson of power by the theologians to aristotle and his followers seemed a novelty to galileo

st augustine or aquinas would say that the bible supported whicheer truth found in nature

24 feb 1616 galileo was ordered not to hold defend or teach the propositions

now silenced, galiileo turned to other things, like using the eclipses of the satellites for navigation

dialogue c9ncerning the two chief world systms

simplicio (Greek aristotelian scholar) vs fillip salviati (died in spain in 1614)

relativity of motion and conservation of motion allowed galileo to discout the idea of the arth's fixed position

ignored kepler's ellipses and presented the sun as the centre of all motions

Urban was angry; galileo was told to come to rome himself or be brought in chans and pay the expenses of his arresting officers

was scheiner responsible for the leaking of the unsigned 1616 document that so angered Urban?

it should have been destroyed as it was of no legal value

galileo insisted that "nor teach in anyway!" were not recalled in ballarmine's affidavit

at siena he wrote to his daughter that his name had been struck from the book of the living

marsenne translated mechanics into French long before it was printed in italian

his worka were printed and translated in protestant countries, including the dialogue and th letter to chirstina

Suggett

ga;ileo argued that earth#s motion was simpler (somewhat ironic since he ignored kepler's work that really did make it simpler)

Galileo porposed the idea of inertia, that an objet, without friction, would never stop moving

had anyione actual;;ty dropped a ball from the mast of a ship? there was no reason to expectit would not fall towards the center of the earth

the ball shared the forward motion of the ship

Galileo reason that if the distance one travelled on the earth as it moved was less than the distance fallen from rest, then thre would be no apparent motion.

the tangent only aMOUNTED TO 5 CM A SECOND, WHICH WAS FAR LESS THAN A FALLING DISTNACE

the idea that the earth could have circular motion was anathema to aristotelians

theory of relativity: motion on a moving frame of rerence was indistinguishable from motiioon on a still frame of reference

1626 record possibly a forgery?

"vain ambitions and ignorance£

"i do not hold and hhave not held this opinioon of copernicus since the command was given to me in me that I must abandon it. For the rest I am here in your hands. Do with me as you please."

"the book of the univere is written in the language of mathematics, and it scharacters are triangles circles and other geomtric figures without which it is humanly impossible to understand a single word of it."

galileo reduced all equations ot eight time, speed and distance

earth air fire and water were irrellevant, only wight mattered

aristotle had been an observer as well as a philosopher

with galileo's death, italy became a scientific backwater

martin marsenne circulated galileo in france

the foudning of the royal society in 1645 led to a discussion of galileo's work

in august 1637, galileo went totally blind

1979: galileo was officiallly forgiven by the catholic church

seeger

several preachers, such as afra luigi maraffe, head of the dominican order, defended copernicus and caleld galileo a good catholic

the universal authority of the bible owas a matter of some conetention in the post-reformation period, galileos interpretation of joshua was seen as ad hoc

24 feb 1616 ultraviolet testibng has shown that if it was fabricated, it was fabricated in 1616 with the other materials

suggested using the frequent (more tha a thousand a year) eclipses of jupiter to determine longiotude by cheeckign their timing at certain locations against the time in florence. muliplied by 15, this would give longiutde. uBNFORTUNATELY, THE LACK OF A GOOD ENOUGH CHRONOMETER MEANT that this was impossible

a combination of chronic illness (both genuine and psychosomatic) kept galileo in bed for much iof 1617 and 1618, meaning he missed three comets in auguest 1618

the jesuits had embraced tychobrahe's corerct view of comets as beyond the highest heaven galileo still believed theiy were exhalations

cosimo 2 died in 1621

maffeo barbarini who ahd written a poem in his honour in 1620, became poope urban viii in 1623

after dix long interviews with urban, he could not change his mnd viz copernmicanims, but was assured of his "virtua and piety"

he also created a microscope

giovanni francesco sagredo was the neutral salviati was the copernican (representing galileo) simplicio (sixth century commentator)

tychonic system was excluded from the two world systems

the earth and the planets had commonalities earthshine moonshine pahases of moon and venus

claimed that a ball dropped from the mast of a moving ship would fall as if the ship were not moving- galilen relativity

parallax was dispensed as the stars being too far away

the fourth day was devoted to the tides

keplers laws were the ebst evidence for copernicanism, yet galileo ignroed them

galielo would have fared better if he had been less dogmatic, miore tolerant and more willing to see copernicanism as an as yet unverified hypothesis rather than established truth

the tides were being given as direct evidence for copernicanism

his own "unanswerable argument" had been put in the mouth of a simpleton

"one who did not fear to make a game of me"

in any other situation galileos jusgment would have been more moderate, but he had made it personal

galileos pupils held prominent academic positions- he could not be allwoed to publicly counter the church

galileo, for his part seemed unaware of the serioousness of his situaation, or the vehemence of those opposed to him

1 october 1532, galileo was handed over to the inquisition and ordered to return to rome. He tried to delaym,but was threatened wjuith chains

he was 69

contrary to his previous denial, in his second interrogation he said "my error thne ahd been and i confess it one of vainglorious ambition and of pure ignmoorance and of inandvertence"

22 june garbed in the frobe of a penitential criminal and kneeling jhe recieved sentence

legend has it that he rose muttering "eppur si mouve" nevertheless it moves. As this would have been borderline suicidal, it has been disputed

index expurgatorius, revoved in 1835

certain recent discoveries that depart from common and popular ioiniions have been noisily denied and impugned, obliging me to hide in silencde every new idea of mine untikl i have more than proved it. even the most trivial error is charged t me as a capital fault by the enemuies of innovation making it seem better to remain with hte herd in error than t stand alone in reasoning correctly

they are not illusiions

u haver observed them for eighthteen months

he had shown them tonumerous friencds and to prelates in rome

sobel

during his interdict, galileo studied poetry and wrote literary criticism

"I have observed many tiny animals with admiration, among which the flea is quite horrible, the gnat and the moth very beautiful, and with gerat satisfaction I have seen how flies and other little animals can walk attached to mirrors upside down"

we know that he wrote plays and poems but only through reference

"thou fixed the earth on its foundation, not to be moved forever psalm 103

I believe that the intention of holy writ was to persuade men of the truths necessary for salvation. such as neither science nor any other means could render credible, but only the voice of the holy spirit.; but I do not think it necessary to believe that the same god who gave our senses our speech our intellect would have put aside the use of these to teach us instead such things as with their help we could find out for ourselves particularly in the case of those sciences of which there is not the smallest mention on the scriptures and above all in astronomy of which so little notice is taken that the names of none of the planets are mentioned.

to ban copernicus now that his doctrine is daily reinforced by many new observations and by the leaerned applying thesmelves to the reading of his boook, after this opoinion had been allowed and tolerated for those wmnay hears durin which it was less follwoed and less confirmed woudl seem in my dugement to be a contrravention of truth. and and attempt to hide and syupprress her the more as she revealed her self the more clearly and plainly

galileo believed comets to be illusions created by the sun reflecting off high altitutde vapours, akin to rainbows.

comets had no substance. Even jesuits at th s point were agreeing with tycho. while galileo had agreed with tycho on the nova, he never accepted this

discourse on comets seemed to directly attack the jesuits first scheiner than grassi

the asayer was a joke at the expense of libra astronomica

"if their opinions and ther cvoices have hte power to call into exiswtence the things they have considered an named why then I beg them to do me the facvour of consieerd and naming gold a lot fo the old hardware that I have about my hyosue"

"sarsi has but to spit upon the gorund and undoubteldy he will see the appearance of a natural star when he looks at his sipplttle for the poitn upwards towards which the suns'; rays are reflected

marina gamba died in febraury 1619

galileo overrated

galileo only formulated a resticted law of inertia

a body’s indifference to motion or to rest and its continuance in the state it is once given. This idea is, to the best of my knowledge, original with Galileo.”

You could very well argue that that’s not really inertia at all because it doesn’t involve the straightness of the direction of the motion, nor does it explicitly say that the motion keeps going at a perpetual uniform speed. It only focusses on indifference of motion versus rest and preservation of the state of motion.

“No one could say why a thing once set in motion should stop anywhere; for why should it stop here rather than there? So that a thing will either be at rest or must be moved ad infinitum, unless something more powerful get in its way.” aristotle

Since he only trusted the horizontal case, Galileo tried to analyse other trajectories in terms of this case. To this end he assumed, without justification, that a parabola traced by an object rolling off a table would also be the parabola of an object fired back up again in the same direction. In other words, “he takes the converse of his proposition without proving or explaining it.” That judgement is in fact a quote from Descartes, a mathematically competent reader who immediately spotted this blatant flaw in Galileo’s book.

Here’s another interesting point that Descartes makes: Galileo “seems to have written [this theory] only to explain the force of cannon shots fired at different elevations.”

When teaching basic astronomy at Padua, Galileo explained to his students that Copernicus was undoubtedly wrong about the earth’s motion. The earth doesn’t move, Galileo explained. Because, if the earth moved, a rock dropped from a tower would strike the ground not at its foot but some distance away, since the earth would have moved during the fall. In support of this claim, “Galileo observed that a rock let go from the top of a mast of a moving ship hits the deck in the stern.” This had indeed been reported as an experimental fact by people who actually carried it out.

In his later works Galileo of course affirms the opposite of what he said in those lectures: the rock will fall the same way relative to the ship regardless of whether the ship is standing still or travelling with a constant velocity. He gives a very vivid and elaborate description of this principle. I’ll quote in it full, it’s a long quote but it’s quite fun:

“Shut yourself up with some friend in the main cabin below decks on some large ship, and have with you there some flies, butterflies, and other small flying animals. Have a large bowl of water with some fish in it; hang up a bottle that empties drop by drop into a wide vessel beneath it. With the ship standing still, observe carefully how the little animals fly with equal speed to all sides of the cabin. The fish swim indifferently in all directions; the drops fall into the vessel beneath; and, in throwing something to your friend, you need throw it no more strongly in one direction than another, the distances being equal; jumping with your feet together, you pass equal spaces in every direction. When you have observed all these things carefully (though doubtless when the ship is standing still everything must happen in this way), have the ship proceed with any speed you like, so long as the motion is uniform and not fluctuating this way and that. You will discover not the least change in all the effects named, nor could you tell from any of them whether the ship was moving or standing still. In jumping, you will pass on the floor the same spaces as before, nor will you make larger jumps toward the stern than toward the prow even though the ship is moving quite rapidly, despite the fact that during the time that you are in the air the floor under you will be going in a direction opposite to your jump. In throwing something to your companion, you will need no more force to get it to him whether he is in the direction of the bow or the stern, with yourself situated opposite. The droplets will fall as before into the vessel beneath without dropping toward the stern, although while the drops are in the air the ship runs many spans. The fish in their water will swim toward the front of their bowl with no more effort than toward the back, and will go with equal ease to bait placed anywhere around the edges of the bowl. Finally the butterflies and flies will continue their flights indifferently toward every side, nor will it ever happen that they are concentrated toward the stern, as if tired out from keeping up with the course of the ship, from which they will have been separated during long intervals by keeping themselves in the air. And if smoke is made by burning some incense, it will be seen going up in the form of a little cloud, remaining still and moving no more toward one side than the other.”

galileo decried grassi as appealing to authority over experimentation

galileo was a poor mathemtatician and so could not follow tycho and kepler's calculations

mathematical accounts of comets are inconsitant- parallax of comets varies

"comets ahve no other origin than that a part oof the vapor laden air is unusually rarified rarified and struck by the sun"

galileo if anyone is skilled to contribute to gemetrical demonstrations and he knows what a difference there is between and the indolence common to many others in this most diffcult of all activities. therefore it is incredible that he would critixcise as false the observations of all mathematicians in such a way that even those of tycho would be included. Kepler

how many times would the world have to be expanded to make room for an entire revolution of a comet when one 400th part of its orbti takes up half of our universe?

“When a ship floats over a tranquil sea, all the things outside seem to the voyagers to be moving in a movement which is an image of their own, and they think they themselves and all the things with them are at rest. So it can easily happen in the case of the movement of the Earth that the whole world should be believed to be moving in a circle. Then what would we say about the clouds and the other things floating in the air or falling or rising up, except that not only the Earth is moved in this way but also no small part of the air [is moved along with it]?”

galileon relativity, constant speed cannot be destinguished from rest

galileo failed to calculate g to within a factor of two

Mersenne: “I doubt whether Mr Galileo has performed the experiment on free fall on a plane, since … the intervals of time he gives often contradict experiment.”

Actually there is nothing “difficult” about it. At least not to mathematically competent people. Mersenne immediately ran the calculations and found that Galileo must have messed his up, because his scheme doesn’t work. There is no such point from which the planets can fall and obtain their respective speeds. Later Newton made the same observation. Galileo’s precious idea is so much nonsense, which evidently must have been based on an elementary mathematical error in calculation.

Galileo, alas, gets all of this horribly wrong. Even though we are supposed to celebrate Galileo as the discoverer of the law of fall, it is apparently too much to ask that he work out this very basic application of it. As we noted, Galileo did not offer a serious estimate for the constant of gravitational acceleration g, unlike his contemporaries who were proper scientists. Therefore he did not have the quantitative foundations to carry out the above analysis, which high school students today can do in five minutes.

Worse yet, Galileo maintains that no such analysis is needed in the first place, because he can “prove” that the rock will never be thrown off regardless of the rotational velocity. “There is no danger,” Galileo assures us, “however fast the whirling and however slow the downward motion, that the feather (or even something lighter) will begin to rise up. For the tendency downward always exceeds the speed of projection.” Galileo even offers us “a geometrical demonstration to prove the impossibility of extrusion by terrestrial whirling.” Those are quotes from his big treatise on this.

Galileo’s claim to fame as a “mathematiser of nature” is certainly done no favours by this episode. He doesn’t know how to quantify his own law of fall, and doesn’t understand basic implications of it. His physical intuition is categorically wrong on a qualitative level, and worse than that of the ancients he is trying to refute (whose stance was quite reasonable and would be accurate if the earth was spinning faster). Galileo even offers a completely wrongheaded geometrical “proof” that the ancients’ conception is impossible, even though so-called “Galilean” physics leads to the opposite conclusion in an elementary way.

Galileo’s error in effect amounts to assuming that speed in free fall is proportional to distance rather than time. This is a crucial distinction in “Galileo’s” law of fall, which Galileo and others at times got wrong. By messing up this very point in his mature work, Galileo is undermining his claim to being the rightful father of the correct law of fall.

Another example. Galileo tried to compute how long it would take for the moon to fall to the earth, if it was robbed of its orbital speed. “Making the computation exactly,” according to himself, he finds the answer: 3 hours, 22 minutes, and 4 seconds. This is way off the mark because Galileo assumes that his law of fall (that is, constant gravitational acceleration) extends all the way to the moon, which of course it does not. Ironically, Galileo’s purpose with this calculation was to refute the claim of another scholar that the fall would take about six days, which is a much better value: in fact it would take the moon almost five days to fall to the earth. That’s Galileo, the great hero of quantitative science, in action for you: bombastically claiming to refute others with his “exact calculations,” only to make fundamental mistakes and err orders of magnitude worse than his opponents did.

think that … the falling body follows any other line but one such as this. … I do not believe that there is any other way in which these things can happen. I sincerely wish that all proofs by philosophers had half the probability of this one.”

This is inconsistent with Galileo’s own law of fall. Once again he doesn’t understand basic implications of his own law. Mersenne readily spotted Galileo’s error. And Fermat observed that the path should be a spiral, not a semi-circle

galileo's claim that a fine chain ssupended from two hooks inline wiht one another creates a parabola was disproven by Christiaan huygens when he was just 17 years old

when experimentation showed that it didn't fit, he explained it away with unforseen factors

galileo believed that tides were caused by the motion of hhe earth

the lunar theory of the tides is found in ancient greek sources

he considered the idea occult; a tie to the moon's occultic association with water

"Why should you reject this cause and take refuge in miracles?"

This is actually not a bad argument

after all, kepler could not explain what "magnetism" in the moon led to the tides, and supposing it existed was to invoke magic

"Mixture of the annual and diurnal motions causes the unevenness of motion in the parts of the terrestrial globe. … Upon these two motions being mixed together there results in the parts of the globe this uneven motion, now accelerated and now retarded by the additions and subtractions of the diurnal rotation upon the annual revolution.”

high and low tides occur six hours apart, two high and two low 24 hours period. Galileo's theory suggests that tides should be 12 hours apart

these must depend on the size depth and shape of local sea basins

tides 12 hours apart are daily observed in lisbon

The inclination of the earth’s axis implies that the effects that Galileo describes should be strongest in summer and winter. Unfortunately for Galileo’s theory, the reverse is the case. Actually the tides are most extreme in spring and fall because they receive the maximum effects of the sun’s gravitational pull.

violates galiean relativity; it would be onservable on a ship

“They draw attention to a difficulty raised by several members about the proposition you make that the tides are caused by the unevenness of the motion of the different parts of the earth. They admit that these parts move with greater speed when they [go] along [with] the annual motion than when they move in the opposite direction. But this acceleration is only relative to the annual motion; relative to the body of the earth as well as to the water, the parts always move with the same speed. They say, therefore, that it is hard to understand how the parts of the earth, which always move in the same way relative to themselves and the water, can impress varying motions to the water.”

opponents of ptolemy appear to have had an early version of inertia or relativity of motion

If galileo had died in `1609, as he very well could have, he would have been forogtten

simon marius disocvered the moons of jupiter one day after galileo

messenger was published 10 days after the last observation

“I do not wish to show the proper method of making them to anyone”; rather “I hope to win some fame.” Those are Galileo’s own words. His competitors quickly realised that, as one contemporary says, “we must resign ourselves to obtaining the invention without [Galileo’s] help.” Still six years after his booklet of discoveries, people who thought science should be a shared and egalitarian enterprise were rightly upset by Galileo’s selfish quest for personal glory. One writes as follow to Galileo: “How long will you keep us on the tenterhooks? You promised in your Sidereal Message to let us know how to make a telescope so that we could see all the things that are invisible to the naked eye, and you haven’t done it to the present day.”

But if Galileo genuinely wanted them to turn to nature he could have shared his techniques for telescope construction. In truth it served his own interests very well that these people were left with no choice but “comparing texts” while he claimed the novelties of the heavens for himself.

his lectures were unoriginal, his mathematical lectures were euclidian geometry, astronomy for medical students

he cast horoscopes for his own family and friends

“I desire that in addition to the title of mathematician His Highness will annex that of philosopher; for I may claim to have studied more years in philosophy than months in pure mathematics.”

why was the boundary of the moon smooth whiole the terminator craggy?

Another indication that many were silently receptive to Copernicanism is the fact that most of the leading astronomers of the 16th century owned Copernicus’s book, and many of them wrote extensive notes in the margins, as was the habit at the time.

Galileo’s dilettantism is so blatant and shameless that Gingerich could hardly believe his eyes: “I had long supposed that Galileo was not the sort of astronomer who would have read Copernicus’ book to the very end. … Still, when I saw the copy in Florence, my reaction was one of scepticism that it was actually Galileo’s copy, since there were so few annotations in it. … This copy had no technical marginalia, in fact, no penned evidence that Galileo had actually read any substantial part of it. … Eventually, … I realized that my scepticism was unfounded and that it really was Galileo’s copy.” There is no need for surprise, of course. Galileo was a poor mathematician. He had neither the patience nor the ability to understand serious mathematical astronomy, let alone make any contribution to it.

Plutarch, a millennium and a half before Galileo, the suggestion that “the Moon is very uneven and rugged.”

Kepler also points out that this was also the opinion of his teacher Maestlin before him, who, according to Kepler, “proves by many inferences … that [the moon] also got many of the features of the terrestrial globe, such as continents, seas, mountains, and air, or what somehow corresponds to them.” That’s from the Mysterium Cosmographicum, 1596, long before the telescope.

In a later edition of this work, Kepler added the note that “Galileo has at last throughly confirmed this belief with the Belgian telescope,” thereby vindicating “the consensus of many philosophers on this point throughout the ages, who have dared to be wise above the common herd.” Indeed, Galileo himself says his observations are reason to “revive the old Pythagorean opinion that the moon is like another earth.”

for instance, he tries to “correct” Marius regarding the inclination of the orbits of the moon of Jupiter. Marius found that these orbits sit at an angle to the orbital plane of Jupiter itself. Galileo claimed, no no, they are actually perfectly parallel to Jupiter’s own orbit. But Galileo is wrong, and his opponent is right.

thomas harriot obsereved the sun through a telescope without galileo, but nurned his eye

who would dare call the sun false scheiner Galileo erroneously claimed—supposedly based on “a great number of most diligent observations of this particular”—that all sunspots had the same orbital period, regardless of latitude. In fact, sunspots near the sun’s equator orbit quicker than those near the poles—a difference of a few days. Galileo was corrected by Scheiner about this.

The sun does not have the equator conveniently marked on its surface, but not far from it. The sun is spinning rather quickly. It makes a full turn in less than a month. As it spins, a point on its surface traces out an equatorial or at least latitude circle. So by tracking the paths of sunspots over the course of a few weeks, we in effect see equatorial and other latitude circles being marked on the surface of the sun.

So the shapes of those paths traced by sunspots show that we are indeed looking at the sun from alternating vantage points. But this does not necessarily mean that we are moving around the sun. The same phenomena could be accounted for from a geostatic or Ptolemaic point of view by saying that the sun is so to speak wobbling. It is showing us different sides of itself in the course of a year, not because we are moving around it but because it is turning different parts of itself in our direction.

orbit, rotation and precession implausible on the sun- galileo

galileo's argument disproves the copernican explanation for precession

“If the terrestrial globe should encounter an obstacle such as to resist completely all its whirling motion and stop it, I believe that at such a time not only beasts, buildings, and cities would be upset, but mountains, lakes, and seas, if indeed the globe itself did not fall apart. This agrees with the effect which is seen every day in a boat travelling briskly which runs aground or strikes some obstacle; everyone aboard, being caught unawares, tumbles and falls suddenly toward the front of the boat.” dialogue concerning the two world systems

works

Two new sciences adheres to the abhorrence of a vacuum

Galileo still nelieved that straight motion was impossible, as it is infinite, and there cannot be motion without an endpoint.

"the novelty of those things as well as some condequences which followed from them in contradiction to the physical notions commonly held among academic philosophers stirred up against me no small numnber of professors as if I had placed these things in the sky with my own hands in order to upset nature and overturn the sciences. They seemed to forget that the increase of known truths stimulates the investigation, establishment and growth of the arts, not its dimunition or destruction"

he asserts his belief in heliocentrism and argues that his new discoveries agree with it

mistrusting their defense so long as they confine themselves to philosophy, these men have resolved to fabricate a shield for their fantasies out of a mantle of pretend religion and the authority of the bible. These they apply with little judgment to the refutation of arguments they do not understand and have not even listened to,

the small number of the intelligent woud be unable to repress the furious torrent of those men, who would find so many more followers in that the gaining the reputation as wise men without pains or study is far more grateful to human nature than consuming ourselves with the restless contemplations of the most painful arts

demonstrated conclusions touching the things of nature and of the heavens cannot be changed with the same facility as the opinions touching what is lawful or not in a contract, bargain or bill of exchange.

before a physical proposition be condemned, it is necessar to show that it is not necessarily demonstrated, and this is to be done not by them who hold it to ne true, but by those who o hold it false.

of natural propositions, some ther eare of all human science and discourse can furnish us only with some plausible opinion and probable conjecture, rather than with any certain or demonstrative knowledge. As for example, whether the stars be animated. Others there are of which we have, or may confindently believe that we may have, by experiments, long observations and necessary demonstrations, an undubitable assurance. As for instance whether the earth and heavens move or not. Whether the heavens are spherical or otherwise. If human reasoning cannot reach them, and thus there is no science to be had of them but only opinion or belief we ought fully and abolsutely to comply with th e mere verbal sense of the scripture.

as to the other sort, two truths can never contradict each other

he cites st augustine re the sphericity of heaven vs the bible describing it as a hide; that when reason and evidence challenge scripture, cripture should be reinterpreted.

"It is not worthwhile to attempt to remove them from their reasons, they being incapable of the contrary reasons that depend upon too exquisite observations and too subtle demonstrations, grounded upon abstaractions which for the comprehending of them, require too strong an imagination."

the bible does not condemn the contrary opinion

a statement cannot be both true and heretical

a statement about which we are not certain should not be considered heretical if we are not certain of its truth, unless it can be proven false.

Io europa ganymede periods calculated to the half hour, callisto to within two hours

realised that sunspots were created and destroyed on the sun's face and so could not be orbiting planets

SIMP. I do not think that anyone believes fables when he knows them to be such; and as to the opinions about the cause of the tides (which are numerous), since I know that there is only one true and primary cause for one effect, I understand perfectly that at most one can be true, and all the rest must be false and fabulous. Perhaps the true one is not even among those which have been produced up to date. I rather believe this to be so, since it would be remarkable if the true cause should shed so little light as not to show through the darkness of so many false ones. But I must say, with that frankness which is permitted here among ourselves, that to introduce the motion of the earth and make it the cause of the tides seems to me thus far to be a concept no less fictitious than all the rest I have heard. If no reasons more agreeable to natural phenomena were presented to me, I should pass on unhesitatingly to the belief that the tide is a supernatural effect, and accordingly miraculous and inscrutable to the human mind -- as are so many others which depend directly upon the omnipotent hand of God.

cambridge

dialogue; three men four days two named after dead friends of galileo day one: early forms of inertia

day two diurnal motion of ht e tearth relativity of observed motion

urban VII god could have chosen to make the tides move in any way he chose, and it is and our hujman minds cannot pretend to a knowledge and certainty about nature that would limit and restrict the divine power and wisdom"

galileo has simoplicio say this

"vehemently suspected of heresey"

dialogo was prohibited

galileo abjured

i galileo some of the slate viincenzo galilei of florence, seventy years of age abandon completely the false opinion that the sun is the ncetnre fo the world and does not move and that the earth is not the centroe odf the world and moves

1534 his daughter died

up until the early 1600s, galileo defended the ptolemaic system

textual scholarship would later determine that much of galileo's early writing was cribbed from the Jesuit collego romano

"more years in philosophy than months in pure mathematics"

benedetti mezzoni criticised aristotle for not using mathematics, galileo studied them

in a letter written to a friend on his deathbed he claimed that in matters of lkogic he had been an aristotelian all his life

galileo's texts are riddled with I/ He beleived in the strength of the individual to rise abocve hte herd, whether the masses or the peripatetics

Eagles are scarce, little seen and less heard. birds that fly in flocks fill the sky with shrieks wherever they settle, and befoul the earth beneath them. but if true philosophers are like eagles, the crows of fools who know nothign is infinite

on motion mistake in claimign the motive pwer of bodies as the difference in specific gravity between an object and teh medium in which it is immersed

galileo's mathemaics was geometrical not algebraic and relied on relationships (ratios) ot absolute qualtities

when he died galileo was dictating a commentary on euclid's definitions

galileo was the first to gather together the issues with inertia and deal with them in a single discussion

distance fallen is proportional to time squared 1604 no later

the distances fallen equal the odd numbers 1 3 5 7 9

if a descending body is deflected horizontally, it continues at linear speed

pierre gassendi confirmed galileo's work on inclined planes and dropped a stone from the mast of a moving ship

ga;ileo never saw gravity as an extrinsic force but as an intrinsic property of a body

all external impediments being removed a heavy body on a spherical surface concentric with the earth will be indifferent to rest or to movement toward any part of the hori9zon and will remain in the state in which it has once been placed

if it is true as ancient philosopehrs believed, that there is a single kind of matter in all bodies, and those bodies are heavier which enclose more particles of that matter in a narrower space, and also occupie narrower places such are those that are nearer the centre

jacopo mazzoni 1597, based a comment by aristotle, bneleved that that one could see two thirds of the cleestial vault from the top of a mountain, and tus if the earth were in motion, one could see two thirds of the celestial sphere. Galileo corrected him with trigonometry

galileo offered an 8x telescope to venisce, taking nobles up to a high tower to demonstarte it. his salary wwas ioncreased from 520 to 1000 florins

but then the senate heard tht the telescope was in use throughout europe, felt gypped and said that his salary would be delayed to the following year and that he would not be allowed to ask for another increase

galileo was peeved; he never claimed to have invented the telescope and his was better than any in circulation

still he would make abetter one

if venus orbited the sun, it would be full when farthest from earth and new when closest

french court beggged him to name a new planet after henryy IV but he couldn't find it

i have onserved that saturn is not a single star but three together which always touch each other they do not move in the least among themselvs and have the following shape the middle being much larger than the lateral ones

to the tuscan ambassador to prague

if we look at them with a telescope of weak magnifican the three stars do not apopear very distrinctly the saturn seems elongated like an olive but with a telscope that multiplies the surface over a thousand time 30x the three globes will be seen very distinctly and almost touching with only a thead fo dark space betwen them, a court ahs been fiound for jupiter and nhow for this old nam thwo attendants will hel him wal and never leave his side

to mark welser

what can be said fo so strange a metamorphsis were the two smaller stars consumed klike spots on the sun have they suddenly vanished and fled or has saturned devoured his won children I cannot resolve what to say in a change so strange, so new so unexpected

summmer solstice 1515 APPEARED LARGER "EARS" and then vanished again

wooton

galileo never published or finished on motion

he refused to drp the idea of impressed force and so failed to grasp the full implication of impetus theory they continue accelerating indefinjitely (already developed by middle ages)

the dialogues were just polished accounts of his intellectual work in padua

cesi found kepler's argumetns convincing galileo ignored them

galileo must have heard of bruno, yet never mentions hm

he was compared to bruno constantly

he copied brinos dialogue form

opn motion is geoctric as it has only one iof down

since all strauight motions are curlved because th earth is curved all motions are circular

erhaps he wanted top preserve the idea that accelleration was a temorary phase and hat contant fall would ensue

a symmetrical curve meant that two motions could be simultaneous

this was exactly the kind of curved path galileo envisioned to expalined the tower objection to copernicus

by two new ciiences gali9leo had come to the conclusion that all objects fall ta the smae speed in a vacuum

also the timing of th ti8des should be constant, but they vary

relativity of movment at a constant speed iot is indistinguishabkle form standing still

the word experiment was first used by alhazens latin translator

galileo read alhazen for a course on optics he took in 1601

william gilbert uses the word experimetn in on the magnet in 1600

gilbnert experumented with round magnets called earthlets

cunning experiments and careful measurements

gilbert concludes that the earth itself has an axis and that it thyus rotates as magnets do

galileo ahd read gilbert by 1602

an object takes the same amount of time to fall the length of a circle as it does to roll down an incline describing aby sector

gilbet had shown that experiments could add new knowlege; galileo ahd shown experimetns could disprove ancient knowledge

galileo never discusses his experientn with planes on on the new sciences only mentioned in notes

galileo had conducted his experimetns prior to 1620 but did not publish until 1638

galileo never attended church and spent his time with cesarecremonini a known atheist

accusations were made that he claimed his horoscopes were perfectly reliable

jesuit tenstion thomas aquinas vs new science

his best option woudl have been to give one to the Emperor who whould have passed it on to kepel, but he darent leta proetsant confirm his results

galileo clock univeral jupiters moons not possible on a b0at?

aristotle deined life after death and believed the universe was eternal he had not ime for miricles

cesi was anti aristotelian

his attempt to claim that sunsopots disprove aristotle on the mutability of the heavens and were compatable with scripture was struck out by censors as a matter for thelogians

galileo argued that he was moved by religious devotion while his opponets were merely simulating piety

there is no evidnece of religious devotion at any point earlier in his life

one heresy galileo was deffintely guilty of was atomism and belief in a vacuum

galileo never asked anyone to pray for him until he lost his sight

in none of galileos letters are there any sponanious expressions of piety

we know that he wrote a treatise naturalisign teh miracles of the old testament

he wrote once about the complexisty of separating providence from nature, and that providence only operates though general laws- heretical

galileo visited rome 6 times

1587 to meet clavius

1611 to demonstrate the telescope#

in 1615 16 to defend copernicanism 6 months

1624 to celebrate the election of barbini as pope

1630 to prppare for the publication of the dialogue

1633 for the trial

galileo was a terrible courtier

the dialogue cntains a claim of priority over Scheiner re sunsopots

viviani did a very good job establishing the ideea that Galieo was a good catholic

galileo's wrotomgs were not pious and the few that were expressed a highly individual idiosyncratic belief in anima mundi

benedetto castelli june 1639 heard news that galiloe had given his soul to christ (after 35 years of friendship)

galileos idea of eternal motion is compatible with an eternal universe zand thus the absence of a crator

urban decreed that no one was to even speak to galileo of copernioanism on pain of damnation

galileo questioned many literal interpretations of scripture (the idea that the universe was created for us is fallacious, since without a universe we would not be here

Galileo's beliefs were characteristic of deism

physics became exxperimental under mersenne?

deciples like trorricelli created thje first artificial vacuum

weilliam harvey weas the fisst person to see a new theory triumph in his lifetime

the Jesuits, who were at the core of the new science, initially supported galileo, but they also had to supoprot thomas aquinas and reject innovation.

By 1632, the jesuits had turned against galileo, but individual jesuitrs still suported him

surface tension and the hydrogen bond would not be dicovered for 300 years

galileo may have been the first to observe sunspots through a tlescope, ut david frabricius was the first to publish, and christopher scheiner the second (1611, 1612)

July of 1610 spring of 1611, galileo is recorded as having shown sunspots to several people

scheiner was an aristotelian and so rationalised the sunspots accordingly

numerous objects orbiting the sun at a low level

in his response to scheiner, in on floating bodies, galileo made no mention of him, a bit of a slap

he claiemd that it made no difference if the spots were on or above the sun

Benedetto castelli had discverd that you could project the sun ona piece of paper instead of looking at it through a telescope, which left you temporarily blinded

using this techniwue galileo could make precise and exact measurements of the sopts movements.

eclipses of jupiter occur at the same time for any observer on earth, and thus act as a universal clock. galikleo hadnt cinsidered how difficult making such observations ona ship on the open ocean would be

galileo made entreaties to both the spanish and duitch gpvernments but the spanish werent interested and the dutch, somewhat ironically, were uable to locate a good enoyugh telescope.

Aristotle was not a Christian- Christianity didn't exist when Aristotle taught. He denied the immortality of the soul, believed in an eternal universe that had never been created, and didn't mention miacles

Galileo initially (1611-12) saught to form an alliance with the Jesuits against Aristotelians

teh book of nature is not written to be understood by us, so investigations of nature must take priotrity over the words of the bible

but according t christianity, nature can be adapted to communicate with us- it's called a miracle

galileo: copernicus had never been declared a heretic and was a pious catholic.

galileo insisted that he was motivated by religious zeal, despite not showing any such zeal at any previosu point in his life, galileo only made expressions of piety when charged with impiety

Caccini claimed that "galileisti" had claimed that god was substance and an accident, that the miracles performed by saits were not real, and beklief in atomism and the vacuum

galieo never prays to saints, paus inmduulgences or asks other to pray for him \9until he goes blind)

galileo was a deist of sorts, he believed in the divine architect but coudl not conceeede a god that would interfere with his own creation

gods providence lay in general laws, not on arbirtrary interventions, this wa heretical, galileo danced around it in writing

since astronomy was tought as part of the core curriculum, any theologian would be at least versed in it. Also, the idea of claiming expertise in specific fields was novel for the time. A man whith no knowledge of construction or architecture could strll give orders to buiolders or archtects

that the bible was innerratnt was the most powerful argument and its resolution the purpose of his ltter to christina (though she likely never read it)

galileo quotes st augustine and st jerome in huis defense of copernicamsnism,. but there is no evideence he actually read any of those words, just useful quotations sent hto him, by sympathisers

in 1633 a new dociment was discocvered prohibiting galileo from holding, teaqching or defending copernicaqnims in any way whatsoever, in any way whatsoever,k either orally or in writing

when this letter was rediscovered in the 19th century, some speculated it was a forgery, since there is no indication that it was required (such a comanned would only have been required if galileo had demurred, and there is no evidence that he did so.

SOme speculate that the dominican (ahted jeduits and wished to have galileo condemned) who wrote the letter had overstepped his instructions

although, as wootton points out, demurring woud have been entirely in charcter to for galileo

galileo was, by most assessments, a terribgle corutier; he did not understand that wehn dealing with an abolsutist ruler, holy or secular, you have to bend your opinions to his won. Galioeo took his own afice.

In 1618, galilo suffered a diplomatic illness, too extreme to go outside and observe comets, though not to have guests over.

1619: Jesuit scientist Orazi9o grazzi£to attack aristotles opinoon of comets" as galileo said

grassi must have thought galileo woudl be happy, he even praises him in his work "thus only comets wremained aloof dfrom the lybnxes eyes"

he could never have been more wrong. Galileo retained aristotle's view on comets and said so in a lecture

Astoundingly, one of galiloes problems was that to acept comets asextraterrestrial woud have made the uiniverse oto large, and yet it was nowhere near as alarge as heliocentrism would make it

"now how many wolds and ho many universes woudl ahve to be assigned to give it space enoughj for an entuire revolutionj when one foryu hundrd t=oart iof its orbit aexxcceeds half of our uiniverse

this multiplicitry of spheres i cannon reconicle with the extreme neatness which nature maintains in all her other works bty retaining mothing which is superfluous or idle.

comess were not fires, reflections of light, like sun dogs

problem is, optical phoneomena change their positions with the observer, comets do not. Everyone familiar with such things knew this

som,e scholars speculate thaqt galileo was merel being p0rovocative

galileo grasped that grassi was channelling tycho- galileo had to remove tycho. he had to destroy him

galileo believed the jeusits had betrayed him in 1616 and, rather stupidly, made that fact public

grassi's respomse was called the astronomical balance

galileo responded with the assayer, a finer balance

grassi had done nothign but attempt to assuage galileo, while galileo maintained that grassi had attacked him

had galiloe not fallen out with the jesuits, it is likely that he could have defended coopernicanism to his hearts content

galileo writing in italiwan was in part a mean sto circument university professors

galileo was an intellectual libertarian, seeibng himself asa lone genius rising above all others, yetr he was also hostile to heirarchy

galileo countered the sling-egg boiling mth by pointing out that we have eggs,a nd slings and stout fellows who can sling them, and all that happens is that they cool faster. Given this, the onlyu lack is being babylonian, and thus that being babylonian could cook eggs

galileo arguing for the supermacy fo fact was new. at the time only authority was required to establish truth

philosophy is written in the very great bvook which always lies open before our eyes -i mean the universe- but one cannot ubnderstand it unless one first learsn to usnerstand the language and reognixze the characters in which it is written. It is wriggten in the mathematical language and the characters are triangles, circles and other geometrical figures without these means it is humanly impossible to understand a a word of it. without these there is only clueless scrabbling in a dark labyrinth

algebra was only just gaining a foothold, and would not see wide yuse until the end of galileo's life

the asayer contained a defence of atomis, which, because it denied essence (the means by which the wine and wafter became the body7 and blood fo chris() refuted transubstantiation

By 1622 Bellarmine was dead. Perhaps then galileo saw a chance to reopen his debate on the tides

6 August 1523, Maffeo Barberini became pope Urban VIII

he praised galileo in a poem, sent to him and signed your borother

eh gegan aoppoiinting lyncaeans to dkeey positions in their administratiion, and his nephew, a cardinal became a lyncaean

to the horror of grassi, the assayer was now dedicated to the poe, and featured his aerms on the front page

galileo threw a key on a boat, to the horror of the passenger whose key it was, and it fell between them

21 april 1624: galileo returns to rome. this time at his own expense.

he met with irban dix times, who outlinedthat he could teach the hypothesis, but not that it was literally true

he also had to acknowledge that god is omnipotent and that he could engineer any number of ways for a process to occur

he was attempting to bridge the gulf to galileo- rather than intellectual cirtainty of the aristotelians, it was best to be humble in the face of nature

Galileo thought that Earth, which shone by reflected light, had to be in motion, as all other planets also shine by reflected light. The Sun, which was starlike, should imitate the stars, which are stationary

"if any oplace in the unicverse is to be called its centyre it is the centre of celestial revolyutions, and everoyon who is competent in this subject knows that it is the sun rather thnan the tearth that is found therin.

letter to ignoli was circulated to test pope;s mettle

it didn't work, thankfuly war broke out and the pope never saw it

due to a quirk in his birth chart, Urban considered eclipses a poortent of his death and demanded astrologers perform magic to ward off bad omens

1630 galileo carried the dialogue to rome

on agust 1 Prince Cesi died, and with him one of the main hopes for funding the publication of the dialogue

castelli wrote to galileo that it woud be best for "fpr mumerous good reasons" to try and publlish the book in florence

the thirty years war was messy, with catholic france siding with protestant sweden. if the pope sided with france, he sided with protestantism

tuscany sided with the spanish, leading many to suggest galileo travel to rome as a private citizen

a false story had claimed that urbans own astrologer had predicted his death the folowing summer. Thankfully the source of the false repot was found, a witness tortured to implicate him

teh culprit ozio morandi, was an anti-aristotelian, and was later found dead in his prison cell. Understandably, his fate unnerved galileo

the florentine and dominican censor wept at galileo's compliance with the church

galileo reassured that teh dialogue woud treat copernicasnism as a dream and a chimera

the dialogue contains a passage on sunsposts almost certainly plaiarised from scheiner

galileo also claimed credit for scheiners discoveries

in 1625 the jesuit scheiner made overtures to galileo claiming to be a copernican

but had written an 800 p0age tome attacking copericanism

galileo asserted that sunspots follow the ecliptic, but sheiner showed that at certain times of year, tehy appear to follow a cureved trajectory

in the dialogue, galileo asserts this as evidence of rhte simplicity of copernicamanism,. since for the sun to presetn itself to a geocentric earth, it would have to be wobbling like a top

urbain was furious he had recieved no warning

galileo pleaded age, infirmity and pietry, but no dice. He was coming to Rome.

galileo was alloweed his freedom out of respect for the grand duke, and would not rule out incarceration

galileos ill health and fears led to him keeping his hosts awake for two nights in a row with screaming

they feared he might die of shock when he was informed he would be transferred to the inquisition

he claimed to have not defended copernicanism in the dialgoeu, whcih was manifestly false, and to have no knowleege of his 1616 injunction

melchior inchofer, a jesuit priest who was an inquisitor at galiloeo's trial, brought up the old claim that he had dnied transubstantiation. It is likely that galileo was threatened with the charge unless he caved

It was the goal of bargerini that galileo be released without undermining the authority of the tribunal

the final outcome was, galileo wrote in a letter to maria celeste, a victory for him and his oppponents

galileo realised he was guilty of at least carelessness, and wanted to work out a relatively painless confession

he was handed to the florentine ambassador, who was paying for his keep out of his own pocket, for two months

emerged, according to an onlooker, half dead

he had to ask permission to exercise

On June 16, Urban demanded that galileo abjur de vehenemnti, which made copernicanism a heresy, and galileo a heretic

at his trial, galileo claimed to never have been committed to copernicansim, and admitted that he had failed to present both sides of the case with sufficient care

He was required to abjure copernicanism, and a copy of his book was burned in front of him

he was sentenced to the prisons of the holy office at the pleasure of the pope, a decree that shocked him, as he had expected only his book to be banned. Instread, urban sent him to the villa de medici

Pope Paul V had pushed against copernicanism being declared heresy. Not so urban

In 1757, a story emerged that galileo mutted and yet it moves, this is almost certainly nnot true

Inquuisitors in university towns across italy were dispatched to decree to intellectuals that galileo was condemned, and that copernicanism was heretical

On 30 June galileo's sentence was commuted to house arrest

he was unable to sleep, and spoke to himself at night, leading to fears he was insane

On 17 december, galileo arrived home. In the eight years of life he had left, he wold never leave

Galileo began work on a book he had promised since 1609, the discourse on the two new sciences

while not about copernicanuism, the sedond part on local motion was q refutation of argumtnss against copernicanism

while he had hooped to publish in italy, the vatican had banned all works by galileo, whatever the topic

teh dutch firm of Elsivier, to this day one of the premier pybblishers of scientific journals, which had already pyublished latin translations of the dialogue and the letter to christina

he had to copy the text himself, despite his failing eyesight

in hid dedication he made up a story in which he had smuggled the text out of Rome during his trial by handing it to the french ambassador. Nothing about that story s true, but galaileo wanted to piss off urban

1627: utban gave a pesion to galileo'sson vincenzo

On 1 April, the same day he leard that the vatican had ceased to hear demands form the florentine government to release galileo, his daughter, maria celeste, the only reason he had chosen his place of arrest, died of dysentery

Galileo thus had to tun to his spoiled son, with thom he designed a pendulum clock

when galileo died in 1642, the church demanded that there be no tombhstone, or burial ina chrurch. A private guarden was reserved for his burial instead, and a proper tomb finally constructed in 1737. W"hen the body was exhumed for transport, that of a woman was found beside him. No one knows who she was

at this point, h three fingers and a spunal vertebra were taken from the tomb as secular relics

"stubbornly and perfidiously assassinating hmself"

Legacy

Galileo had to build an audience for scientific work, while Newton could assume such an audience was already in pplace "Galileo crated a place for scinece in intellectual life"

age of discovery zoologicql qne botanical gardens

rise of printing, individuaql learning

galileo's middle finger a tragic mutual incomprehension has been interpreted as a reflection of a fundamental opposition between scinece and faith." jphn paul 2 1992

"Propositions arrived at by purely logical means are completely empty as regards reality. Because Galileo realised this, and particularly because he drummed it into the scientific world, he is the father of modern physics, indeed of modern science altogether." Albert Einstein.

galileo's impact was due in no small part to how readable his text was kepler and copernicusw did not write for the masses

By 1638 Galileo was completely blind

The publication of his books was banned in catholic countries

galileo to the comte de noailles: " I had decided not to publish any more of my work, and yet, in order to save it from complete oblivion, it seemed to me wise to leave amanuscript copy in some place where it woulld be available at least to those who follow intelligently the subjects I have treated."

Galileo handed the manuscripts to him when he visited rome

"as if moles were grown to the size of whales, but maintained the instincts of moles"

"galileo did not invent the telescope, nor the miscroscope, nor the thermometer, nor the pendulum clock. he did not discover the law of inertia, nor the parallellogram of forces and motions, nor sunsopots. He made no contributiion to theoretical astronomy, he did not thrown down weights from the leaning tower of pisa and did not prove the truth of the copernican system. He was not tortured by the inquisition, did not languiish in its dungeons, did not say eppur si muove, and he was not a martyr for science."

galileo did not believe in paradigm shifts. He reminds the reader that all copernicans were one aristatelians

the house of medici played a role in the initial estblishment of the galiloan myth, determined to turn their humiliation from patroniasing a heretic into another of their long string of reforrms and reconstructions

in the 19th century, debate raged in England about whether galileo had been tortured

the and yet it moves quote likely originated in a work published in London in the 18th century

rene descartes rectilinier motion maintined