Galileo: 400 Years of the Telescope

from the Library of Congress in Washington DC welcome I'm Jennifer Harpster I'm a digital reference specialist with the science technology and business division here at the Library of Congress I'd like to welcome you to today's program 400 years of the telescope will Galileo four hundred years of the telescope this program is a first in a series of programs in 2010 that is presented through a partnership between my division and NASA's space Goddard Flight Center our speaker today is Michelle thaller she wanted to make astronomy the focus of her life and I'm quoting her I just couldn't get outer space out of my head she received a Bachelor degree in astrophysics from Harvard and a doctorate in observational astrophysics at Georgia State University so you specialize in the life and death of massive stars to a large extent Michelle's work involves a telescope as an observer she has used the Hubble Space Telescope the roast at x-ray satellite and the International ultraviolet Explorer satellite she parts her love of space to the general public by working in outreach and education for ten years she mantid the spitzer space telescope outreach program at Cal Tech and NASA's Jet Propulsion propulsion lab but fortunately for us she has moved east and now she is the assistant director of space for communications at Goddard in celebration of 400 years of the telescope Galileo's first telescopic observations and the publication of Siderius new kiaus nuncius or new Kias whichever Ladin you want to prefer all the way also known as starry messenger michelle take us on an illustrated journey of the real Galileo and last but not least we are delighted to have the chief of our rare books and Special Collections division briefly display the display the library's unbound copy of Galileo's 1610 Siderius nucleus following the lecture so please join me in welcoming dr. all right well good morning everybody we have a little chance to relax today together I hope and enjoy and one of the most incredible stories that I know about in modern science Galileo Galilei is truly a larger-than-life personality and as many of you probably know and please come in and for those of you that are still here coming in please don't stand on ceremony I guess I should do a couple things first of all I know that they're webcasting this would you if I can talk to the camera person would you like me to try to stay behind the podium or if I move a little bit out or I'll try to stay here okay that's a little unnatural for me I'm a bit of a wanderer normally so I'll try to stay put as much as I can here but at any rate I'm a professional astronomer I am NOT historian of science and this year was an incredible year for us because 400 years ago so much was going on in the world of astronomy the field revolutionised itself and we're talking four hundred years ago to the day in some cases Galileo was making his observations this winter four hundred years ago and he would be publishing his incredible groundbreaking and the pronunciation is kind of funny Siderius nuncius is probably how he would have said it medieval Latin had sort of a soft sir I actually studied strangely enough classical conversational Latin and I tells you how much of a geek I am and we would have said Siderius nokia sin the classical pronunciation so I may I may switch between the two just but I'm not thinking about it realized that both have some degree of scholarship behind them on one thing I'll also say I'll be talking a lot today about the Protestant versus Catholic Church and I wanted to find some terms because also at this historical period in time the Catholic Church would have also been the Protestants would have called themselves Catholic as well so when I say Catholic I do mean the Roman Catholic under the Pope versus the Protestants so a little bit of terminology there all right this is a story which like I said 400 years ago I could almost picture this person I almost feel like I've met him after researching him so what we'll talk about today there are probably people in the audience there a few that I see already that I know probably know more about Galileo than I do and yes I know and the stuff that we're going to talk about today is fairly non-controversial we'll talk about person these events things that are very well documented but as far as some detail hopefully we'll have time for some questions and I welcome suggestions and answers from those who are Galileo experts so onward a little bit of a personal note here I have found this period of history fascinating for much of my life and I've done a lot of research myself just for fun I actually belonged to a Renaissance dance troupe we translate original dances from the manuscripts the French and the Spanish and perform them and I have the first time I did this particular lecture was the Jet Propulsion Laboratory in full 17th century costume with a Medici ruff and all of that and the venue we talked about it actually at our telecon but the venue was a little small for that so we won't do that today but but there's me sort of enjoying a bit of a 17th century lifestyle with my husband there are a couple questions I hope by the end of this talk will answer and what we'll think about at least and this is an incredible story why really was Galileo persecuted for this idea that the earth is not the middle of the universe why did the church care so much there's really nothing in the Bible about it there are some references to the Sun going around possibly the Sun hanging in the sky during a battle but the Bible doesn't say all that much about this why did the church think this was so important why were they persecuting people for this belief even when observations clearly showed otherwise that the earth is not in the center also who was Galileo and where did he fit into Renaissance Society this was a courtier this was a member of the Medici court a very very high profile person this was not some scientist working alone in a little lab with nobody ever hearing about them this is a public figure and so we'll talk about who he was and how his life sort of bore itself out what did he observe I'm going to be showing you scans from the Siderius nucleus and other books that show exactly what he observed and why it proved the earth could not be in the center there was no longer any question then we'll talk a bit about the politics that happened afterwards saying that Galileo was a larger-than-life personalities putting it mildly this was an arrogant obnoxious brilliant person who pissed off even his closest friends he was friends with the Pope to begin with they ended their friendship after he published the the account of the earth being not at the center of the universe well the what really happened in that story and also I'd like to end on why I admire Galileo so much as a scientist as a modern scientist I really think of him as the first person that I recognized as someone living a life like me thinking like I do an incredible personality okay all right where did all of this geocentrism start now I mean all of you probably realize you remember being a kid the idea that the earth moving is a ridiculous idea the idea that the earth is hurdling through space at many many thousands of miles an hour and that's just around the Sun we were going faster when you compare how much we how fast we go around the galaxy or even other speeds this idea is not an easy one for us to grasp and much of the church doctrine really focuses on this man named Aristotle who as you can see live from 384 to 322 before the Common Era Aristotle was a student of Plato and a tutor of Alexander the Great and one of the reasons we know a lot about this person is this was a very high-ranking person the tutor of Alexander the Great had a chance to leave a lot of records behind as to what his thoughts were um he's the father really of what we think of as modern logic following proofs from one proof to another a flow of logic he formalized this he came up with the idea of axioms there are truths you can prove through reasoning and these are universal truths that are undisputable he also devised methods for experimenting for decision for figuring out how you know knowledge so I mean this was not somebody who was against experimentation however in his system the idea of deduction and reason went hand in hand with experimentation that you should agree with each other and if experimentation didn't really match the way his system of logic worked he would often sort of say well perhaps the error is in the natural world or an observation the natural world isn't perfect you'll see that he was a student of Plato who of course thought of the natural world is very imperfect as sort of a shadow of the real reality now um he taught that all celestial bodies anything above the earth was perfect and eternal and unchanging and that the motion of the planets the five they knew of back in ancient Greece was perfectly circular and regular they were they went around the same speed around the Sun perfect circles and the earth is made of corruptible essences earth fire water and air are changeable things above the earth its quintessence the fifth quince the fifth essence unchangeable perfect so anything above the earth by definition is different from us it is very very intrinsic nature okay what did the church have to do with Aristotle Aristotle was obviously pre Christ a pagan philosopher well a neat thing happened when finally Europe broke out of the Dark Ages and of course the Dark Ages perhaps are a little bit miss named but it's amazing to think that we had actually lost all knowledge of the Greek philosophers and scientists and playwrights and all of the arts in ancient Greece Europe lost that knowledge it was preserved in the eastern part of Europe and Constantinople in the Arabic kingdoms at that time and when when the Crusaders went out to conquer Jerusalem along the way they found this knowledge that had been lost it was incredibly exciting incredibly fashionable and one of the people that really seized on this was an Italian priest named Thomas Aquinas now Thomas Aquinas you can see 1225 1274 he's a Dominican priest that is thought of as the the real essence of what a priest should be extremely reasonable the idea that faith and God can be arrived at by logic by reason he loved Aristotle he loved this elegant complete system of the world Aristotle wrote about how science nature religion ethics the arts geometry all this is one continuous system so it really was an incredible thing for Thomas Aquinas to find this knowledge you know philosophy oh that's all right philosophy at this time in Europe was a bit more haphazard he they loved the Greeks so as you can see what happened is that Thomas Aquinas finds this knowledge and one of the things that he read there was a famous Roman politician and writer named Cicero and again I'll do my classical Latin it was kicker Oh actually yeah Kay Carell wrote a history of philosophy during the Classical Roman time during you know the reign of Augustus Caesar and he really loved Aristotle so some of the first books that Thomas Aquinas comes across coming out of the eastern parts of Europe coming out of the Crusades are Aristotle by the way Thomas Aquinas actually had five proofs of God that some of you are probably familiar with it proving reasonably why God should exist and these are based directly on Aristotelian logic so under the influence of Thomas Aquinas Aristotle became unquestionable in church doctrine now the problem with this stuff is that not everything in the sky seems to move that perfectly and there was a long known problem with the planets in that when you watch Mars you as you watch Mars night tonight move across the sky Mars appears to stop and move backwards and then continue on its way it's called retrograde motion and what you can see here in the diagram is you look at there these are this is actually the retrograde motion of Mars for 2003 if you map where Mars is in the sky night tonight over in this case I guess we're going from probably a couple of months then you actually see Mars make this backwards movement well that doesn't sound very perfect what's it doing and in order to make sure everything had this perfect circular motion they added something called epicycles where as the planets orbited around the Earth they would actually also be orbiting on these little extra circles and still everything was perfect everything was uniform and these epicycles explained this retrograde motion unfortunately they don't work that well when you start taking better measurements of the position of Mars it doesn't correspond very well to a perfect circle moving on a perfect circle and so there was a famous astronomer at Alexandria Ptolemy and he began to add more and more epicycles to try to get this more and more accurate you know we just as soon as people were able to make very good observations of where Mars was observations got better over time where was it respect to the other stars how was its path changing the circle thing wasn't working you added epicycles on top of epicycles on top of epicycles so there was this in elegance to the Aristotelians system when it came to epicycles so heliocentrism let's now switch a little bit and talk about when the idea that the Sun was the center of at least our solar system if not the universe came about and a lot of people seem to think that this was something that Copernicus came up with as a rather European centric view Copernicus came up with this some time however heliocentrism goes back a lot farther than that and to give you an idea I want to talk a little about somebody of Aristarchus of Samos now remember Aristotle was about I think we're talking about 322 that was about round you round about the time of Aristotle Aristarchus of Samos is actually writing only about 10 years after the death of Aristotle by I should say I think he was born actually about 10 years after the birth of Aristotle so he's probably writing in the vicinity of 40 years after Aristotle we're talking more than 2,000 years ago eric Aristarchus of Samos actually had proof that the earth could not be in the middle of our solar system so why didn't this idea take over from Aristotle it actually is the correct idea um Aristarchus is not much of a formal philosopher he was more of a natural philosopher he study the natural world he wasn't lauded all that much by the Romans they didn't mention him but Aristotle and his incredible universal system got a lot more attention he also was from sama salif's is a relative backwater town of Greece so he didn't quite have the profile that Aristotle did as well interestingly enough galileo didn't know about the work of Aristarchus he actually mentions it in a famous letter that i'll talk about later on called the letter to the Archduchess cristina okay what did he what Aristarchus observed how can we show that the earth is not in the center have you ever asked a grade-school kid you know without a telescope without any other scientific instrument how could you prove to me that the earth is not the center of the universe seems obvious the earth is not moving we are the center while cleverly he looked at lunar eclipses a lunar eclipse we now know is when these the moon actually passes into the shadow of the earth and as you can see here this is a time-lapse of a lunar eclipse and if you notice you can actually see the curve of the earth on either side here the Earth's shadow so as the moon goes through a lunar eclipse you see on either side I'll just tip up a little bit so far two images of the moon I'm sorry a little hard to see that with the podium you can actually see a curved shadow on the moon in both cases all right that's the earth shadow now the Earth's shadow as you can see is a lot bigger than the moon but you can see sunlight all the way around the Earth's shadow so there's a shadow of the earth but something is glowing on either side of that shadow there's light on both sides and he also noticed that you get lunar eclipses at many different kinds of angles sometimes the shadow hits the top of the moon sometimes it hits the side of the moon sometimes it goes right over the moon and there's a total lunar eclipse now the only object that can project a circular shadow from any direction is a sphere so that's a proof that the earth is a sphere the Earth's shadow from any direction you look at it is circular the only shape that can do that is a sphere so we know the earth is spherical you'll also see that there's light on either side so whatever the Sun is whatever is projecting the light must be larger than the earth relatively simple reasoning why should something larger than the earth go around the earth doesn't it make more sense that the larger object should be the center and the smaller earth should go around in fact Aristarchus actually estimated the size of the moon using this his measures of his measurements were not great he didn't really have a very good way of making very precise measurements of angles he didn't get the perfect distance to the moon or the size of the moon but he was working on it in some cases I'm kind of amazed how close he came he had a bit of trouble there was one time he actually tried to measure the distance to the Sun using this and he reasoned that when the moon is at half phase the earth the moon and the Sun make this sort of right triangle as you see in the diagram there and if you can measure the angle between the moon and the Sun you can use trigonometry to figure out what that distance is if I if I could go over to the screens I probably go and point out how that worked by that you can probably see that there a little bit he didn't get it right but he estimated the Sun being about five million miles away and truth the Sun is about 93 million miles away but five million miles away is a lot of distance for a person from ancient Greece you know that that's bigger than their local world so he had this idea that the Sun was very far away he estimated the Sun to be about five times diameter larger than the earth the the Sun is actually many times larger than that's about a hundred and ten times the Earth's diameter however this person 2,000 years ago was beginning to get the scale of our solar system right and he actually also estimated distances to the stars and this blows me away he assumed the stars were like the Sun and he said okay well if they're that faint in the sky how far away does that have to be he actually drilled a plate with tiny little holes and he would hold it up to the Sun and he would see how bright the little pinpricks of light were and compare them to the stars and he used that to estimate the distance to the stars is much farther away than the Sun now he had a better explanation for this retrograde motion the retrograde motion is very easily understood as what you see when one planet passes by another in its orbit around the Sun and as you can see here you know on the bottom of the diagram over to like to your right the earth is actually going to be passing by Mars in its orbit and the classic example is when you pass a car on on the freeway okay you're driving you know alongside a car you both seem to be going forward to your perspective and then as you pass by the car appears to move backwards against the background yeah but that's retrograde motion you're passing something by and it appears to move backwards you're both moving forward but the earth - sort of bypasses Mars and you get this little backwards motion Aristarchus had this figured out this is what happens just a little note for those of you who think that Christopher Columbus discovered the earth was round I unfortunately I don't think many people do hopefully I actually was asked to say that I do a lot of television and the Discovery Channel one time had me scripted to say well when Christopher Columbus decide you know discovered the earth was round no definitely not the earth being a sphere has been known for a long time even in Europe we have Globes older than Christopher Columbus so but the circumference of the earth was very well known in ancient Greece Aristophanes and again I really if you don't know the technique you use he just watched one day one day there was the Sun would Shine directly down away in Alexandria but it wouldn't shine directly down a well in Syene a little bit of ways away so that meant that that there was a curved surface and he actually measured the circumference of the earth to better than 1% so he measured it at yeah thirty nine thousand six hundred ninety kilometers the a circumference so I mean we actually even knew the scale of the earth back then okay on the Copernicus okay so Copernicus wasn't the first person to propose heliocentrism and one of the myths as well is that at the time of Copernicus this was some sort of huge offence Copernicus really was never threatened with heresy or with punishment he might have been a little nervous because he was keeps contradicting Aristotle and contradicting Aristotle did go against the teachings of the church but at the time Copernicus was publishing things were slightly more relaxed Galileo found himself in a very bad time in history where Catholics and Protestants were fighting very very contentious Lee when Aristotle announced his idea about the heliocentric universe he actually wrote to the Archbishop of Capua and we have a little bit of excerpt of the letter that uses with the utmost earnestness I entreat you most learned sir to communicate this discovery of yours to scholars at the earliest possible moment to send me your writings so he was actually encouraged by his local church authorities to publicize this heliocentric idea was interesting idea wasn't Aristotle it was controversial maybe a little beyond the pale but Copernicus himself was not persecuted for this belief things were really changing at that time in Europe like I said the Reformation had happened and now courts were taking sides there were some countries that were Protestant some countries that were Catholic and in some cases there were countries that tried to have some sort of sense of normalcy between the two groups Elizabeth the first is very famous for encouraging peace between Catholics and Protestants other countries it was incredibly violent you know you risked your life by taking mass if you were Catholic or by having a Bible that wasn't in Latin if you were Protestant I mean people were killed for this lots and lots of people also the idea of the earth not being in the center was difficult to take I mean one of my favorite historical figures from this particular time is T Cobra he Tycho Brahe he was a Danish astronomer and again a very very larger-than-life person he's very famous for his gold nose have you guys heard is it people some people have heard to keep Rocky ok he was an astronomer to mathematician and he supposedly got in a duel about who was the best mathematician as a young man and got the edge of his nose sliced off and from that point on were either a gold silver or possibly copper nose that was held on with wax and he he famously when I started researching this talk I couldn't believe this so I actually there actually is evidence he had a tame moose and a moose it would have been a North American animal that that would have been incredibly rare and incredibly expensive to bring a moose over there is some scholarship it was an elk and not a moose but there's there's actually there appears to be controversy as to whether it was an elk or a moose he fed it on beer and unfortunately the thing died after it fell down the stairs after too much beer I Wow now um what an amazing idea to be an astronomer before the age of the telescope this is before telescopes right how are you an astronomer without a telescope well he had this incredible island called Arana Borg the place of arania the muse of astronomy and he had giant buildings set up with with basically protractors things to measure angles on the sky and you'll notice at the bottom there is actually a woodblock print of Tycho Brahe he sitting in one of these giant angular measurement devices in his observatory this is all ruined now actually I've been to the site of Rhonda Borg there's a little bit of foundation left but unfortunately none of the buildings are still standing but he had very very good measurements of what the angle in the sky of these planets were he could not deal with the idea the earth was moving and he proposed what he called the Taconic system which is a bit of a bastardization between geocentric and heliocentrism it was very evident now the planets orbited the Sun but the earth couldn't move so what he did is he had the Sun go around the earth and all the planets go around the Sun so as you see can you see from the diagram there you got the earth in the center and the Sun still goes around the earth but all the planets orbit around the Sun except the earth the earth is still so you know he just couldn't deal with this idea that the earth might be moving all right again to give you a sense of what's going on in Europe there's the amazing Johannes Kepler and this is a very very important anniversary for him as well this year he was a German mathematician and he actually wrote Galileo as soon as he heard Galileo had this amazing new instrument the two men had communicated before he really wanted one a Galileo never gave him one I think the idea of having competition from Kepler was a little too much I'm sure he obtained one at some point but never from Galileo in 1609 he wrote the astronomic anova and in this book on astronomy not only did he have a heliocentric universe with a Sun in the middle but the planets didn't go in perfect circles they went in ellipses and they actually changed their speed when they were closer to the Sun they went faster and they got slower as they went away Kepler's laws of planetary motion these are the laws that I still study today in basic physics 400 years ago this person had got that now a contrast is England England was also a Protestant Court but quite behind the time scientifically Elizabeth did support heliocentrism mainly because it pissed the Catholics off seriously I mean if the Catholics were going to say the earth is in the center and other courts of Europe Protestant wise were going to go with heliocentrism that was a political decision for Elizabeth the the primary scientist in her court was a man named John D and I do use the term scientist with big quotation marks here all scientists at this time did make some money casting horoscopes Galileo did Kepler did all these people so there wasn't a real true separation between astrology and astronomy John D however was a bit beyond the pale not only was he the Queen's astrologer and he was the only one allowed to cast Queen Elizabeth's horoscope for anyone else it was a treasonous capital offense if you tried to cast the Queen's horoscope you would be killed and the reason is you might be able to predict the time of her death this was serious I mean this was looked on as a science and if you could predict when the Queen would die you could influence politics now John D got a lot of his advice from angels that he see really serious he got advice from angels who would speak to him through a mirror through a looking-glass and John Dee was actually honest enough to say that he could not see or hear these angels but his assistant could so John Dee had an assistant that would actually gaze into both crystals and mirror which at the time was sort of a magical device and and and have prognostications this way this was the court of Elizabeth the first idea of science all right galileo galilei let's now start on the story of him and concentrate mainly on this person so we've seen heliocentrism is nothing new people have known about this for thousands of years geocentric geocentrism versus heliocentrism is a political religious divide right now into this environment galileo was born 1564 he was born as the oldest of six children of vincenzo Galilei a noted musician he was a lutenist and he was sent to the University of Padua his father wanted to be a doctor so very very typical family want to have a doctor in the family so he actually didn't stay in medicine very long he very quickly changed to mathematics a little bit of a note here on the the pictures of Pisa the the you all know the Leaning Tower of Pisa you can actually see it at the very end the far right hand side of these are these pictures and that's a tourist you know in front sort of pretending they're propping up sits making take a picture with their hand against the Tower of Pisa everybody does that you may have heard the famous myth the Galileo dropped two balls off the awful Leaning Tower of Pisa to see if two objects of different weights fall the same rate there's no evidence of this one of galileo students did claim that he did this it's not against his personality galileo loved big public spectacles he loved attention for his experiments we don't have any record of him doing it but he may have done it okay in 1592 he actually moves to Padua to become a university of mathematics Padua is a city that was at the time under the control of Venice now this is very important there are very powerful city-states in Italy Venice and Florence are two competing city-states and they also want to jockey against each other you know what what Florence is doing Venice would kind of like to encourage something else to happen so the Florentines were much more conservative and much closer to Rome in their philosophies the Venetians had kind of stick it to them and so the Venetians encouraged beliefs like heliocentrism these these more fashionable new ideas because of a political conflict with Florence so he he actually was a very pop professor he caught the eye of the court and the Medici court actually that the grand duke ferdinand decided to bring him to florence to tutor his son so at this time as well and we'll mention this a little bit more later he did have three children and the children were with marina de gamba his housekeeper he never married marina this was not considered all that unusual at the time I mean nobody as far as we know really chastised Galileo for this this wasn't really a scandal Galileo was of a certain class he was a professor he was he was he was entering the court scene and having a few illegitimate children on the side with your housekeeper is something that happened so like I said that this perhaps shouldn't be viewed quite as salaciously as as it might do now a trouble started when in 1604 a supernova explosion happened this is a picture actually this is how the supernova remnant appears today this was a star that exploded and I'm not I actually knew this once I used to know exactly how far away the star was I actually helped make this image so this is an image that's near and dear to my heart but with the other light reached earth in 1604 and all of a sudden for a few days there was a new star in the sky now that goes against Aristotle's idea that everything is unchanging in the heavens and Galileo pointed this out and and pointed out why this meant that Aristotle was wrong he was very blunt about it he actually used parallax parallax is basically when you look at something from one angle and then from another angle it appears to move you the classic example is if you hold your thumb out and you close one eye and then another your thumb appears to move against the background things that are close to the earth you actually could observe them against stars and see that they move over time they have a parallax a shift this object didn't do that so Galileo argued this must be very far away and so the idea that a star blew up was causing him some trouble the Aristotelian already took note that this guy was was a troublemaker a little bit about his family then I mean so that sort of went away there was the controversy of the 1604 supernova that kind of died away he settled into court life into professorial life um we have wonderfully preserved letters from Galileo - probably his favorite child the problem with the two daughters he had two daughters in the Sun and the two daughters were really unmarriageable in this society they were illegitimate even though their father was a popular professor a member of the court he really couldn't do anything for them there was no way to marry a young woman who didn't have any official family so the best thing he could do for them is put them in a convent he put them in the convent when they were 12 and 13 years old and even at this time that was considered too young for a woman to make vows you weren't really wise enough in your own mind he got special dispensation from the Pope to put him in the convent so the convent was the the Poor Clares in the san mateo convent of our century and this was a very very austere convent I think many of them were at this time sois ramirez maria celeste often writes to him for more food for warmth they were very very Spartan in their existence but the two exchanged letters and we have over over I believe about 300 letters surviving from these these two unfortunately as a nun when maria celeste died they burned all her belongings they didn't archive them they didn't keep them she was just a nun in this this convent so we have all of Galileo's letters from her he kept them but we don't have any back we don't have any of the ones that he actually wrote her and there's a neat book by Davis Oh Bell called Galileo's daughter which talks about this the letters unfortunately I think that the right word was used earlier today is rather banal she talks to him a lot about sewing his collars doing his laundry preparing medicines for him but she was also well aware that he was getting in trouble with authorities and when Galileo would be asked to do a penance for those of you that are Catholics if you sin against the church you've done something wrong you have to say a number of rosaries she would do them for him so she was aware that he was getting in trouble because she was doing his penance they have a very interesting person what you see that that little diagram in the middle of the page is a horoscope that he cast for her so he actually you know was in constant communication with her a little bit of an aside a relatively large crater on Venus has recently been named after her so there is the maria celeste crater that's a radar image the big grey square there and a picture of Venus so we now have a crater commemorating this this woman as I mentioned Galileo was very popular he was very good at spectacle at getting the public involved in what he was doing he was very good at seeking patronage and the most powerful family at the time in Italy were the meta cheese this is a crest of the Medici is carved in marble whether there are other palaces the man she's ruled Florence and they often were the people who appointed popes they were incredibly politically powerful he was brought to Florence to tutor the son of the Grand Duke this is a big appointment ok the Grand Duke is one of the people that rules Italy and he was actually sent to to tutor Cosimo the second the son of Ferdinand now Cosimo the second is really wonderful we actually have a baby picture that that's a portrait of Cosimo as a baby over on the left and the portrait over on the right is a posthumous portrait he didn't live very long he only lived to be 31 but he married an Austrian princess and fathered 8 children and the the person that's two behind him over to uh to your right in the dark clothing that's his son that's Ferdinand Oh so Cosimo ii was Galileo's pupil and he did actually rise to become the grand duke a very close friend incredibly powerful protector of galileo florence like i said it was an amazing place i mean a center of culture a center of political power much closer to rome than not not so much geographically as politically belief wise so when when Galileo moved away from Padua into this more cosmopolitan setting he was moving away from the protection of a court that liked outliers that like people that could be a little difficult with the authorities here he had to be a bit more careful in his politics now at this time people were beginning to invent what would soon become the telescope the telescope was not invented to look at the sky was actually invented to look out at seed Dutch spyglasses the first records we have are of Dutch sailors using these both to cite ships on the horizon but there was also a political reason for it - at a seaport you really couldn't know what ship was going to come in bringing sugar or bringing fabrics and so when a ship arrived there was sort of this on the market all of a sudden there was a lot of sugar a lot of fabrics in the port and so by using spy glasses they could recognize boats very far away and then start investing and buying so there was actually there was actually an economic reason to use these as well and of course defense I mean if you see an enemy fleet coming and you want to see them as far away as possible so these were getting a lot of interest at the time they magnified about two times so I mean they've been really not very much magnification at all Galileo improved this to three times and and for this he actually had a huge demonstration he went to Venice and he actually gave a demonstration to the nobles from the bell tower in piazza san marco and we know it was recorded it was August 25th 1609 he was actually given a professorship and a pension for life because of this for service to the city of Venice he was awarded a pension for life just because of that he hadn't pointed it up at the sky yet this is just for his use of the spyglass here are some Galileo era spy glasses that there was there were some wonderful displays this year all around the world of original telescopes I think there are at least two that they know Galileo may think that's all but these are at least period telescopes from Galileo's time they're beautiful look at the paper all the colors I had a chance to hold some of these I was at the Adler Planetarium and they let me hold some of these 17th century telescopes amazing ok so Galileo obviously then was the first person to make astronomical observations with a telescope right no no actually not we actually know very certainly that he was not because this English man named Thomas Harriot there's a drawing that you see there over on the side of the Terminator of the moon the shadow area of the Moon and it's dated you can just see 1609 July Galileo began his astronomical observations in the winter of 1609 so he said in his journals so there was a person that was already using this but he didn't publicize it very much so unfortunately we really don't know if Thomas Harriot is the first person to use the telescope these are some drawings of the the one on the the left is actually the drawing that Harriet made of the entire moon and then the one on the right is a sketch by Galileo as you can see that the sketch by harriet is much more accurate in terms of where the dark and light areas are on the moon in the case of Galileo he very well may have been just sort of looking at sort of the the view through his eyepiece his intent was not to make a whole map of the moon but it's a little bit sketchy er he's demonstrating a principle the craters have these raised walls and they're casting shadows but Harriet may have even made the better maps of the moon to begin with now after spending a winter and think about this so that there's a man working in Italy in his backyard literally with a spyglass I mean a good pair of binoculars is more magnification than this at that time this was the premier astronomical observatory in the world you know the world would change on this man working in his backyard excuse me he came out with a book about what he had observed and the amazing thing that's going to happen today later on is we have an original copy of this book a 400 year old book that's going to be displayed right outside so if you would like to see the original Siderius nokia's that's an incredible proposition there's not many people that actually get a chance to see that I really thank the Library of Congress for that opportunity now this is a this is actually a scan of an original Siderius that he gave away to a courtier that is actually his signature at the bottom so that that's an autographed copy of Siderius nuncius to accord here and again this was received to great acclaim knowing how to really push patronage one of the things we'll talk about is he discovered moons around Jupiter he called them the Medici and stars after his patrons unfortunately that name did not really a stick around and this is another myth um one of the things actually I'll just sort of go here um one of the myths is that people didn't believe Galileo was seeing things through his telescope there may have been one or two people that said okay you're looking through a silly little tube and you're telling me you're seeing things very far away the thing was the Jesuit astronomers were very very forward-thinking at the time had almost immediately whatever Galileo had in terms of instrumentation in terms of observational knowledge so the jessa what astronomers almost immediately confirmed every Galileo observed and they actually honored him at a banquet he was very popular with the Jesuits at this time they loved these observations here's a little diagram of the telescope one of the first things he mentions in this book is he looked at the Milky Way and what an incredible idea that when you look at the Milky Way even through binoculars try it sometime the sort of lightish area resolves itself into many many thousands of tiny stars what an incredible idea that God made stars that can only be seen through an instrument why did he put them there sort of makes us feel not quite so central anymore maybe not even so central to God's plans these are some diagrams of the constellation Orion from the book and again in Orion he discovered far more stars than you can see by his naked eye and even to the map of the nebulae Orion Nebula yeah a beautiful place where there are thousands of stars being born right now so the idea that there were more stars than you could see was an incredibly profound philosophical idea here's a I think this is a it's the Pleiades I believe yeah I did the Pleiades in the presa Peak altar star cluster I loved the illustrations hoping we'll have a chance to actually look at some of those later on here are some moon maps and as you can see the idea that the moon was a perfect object Aristotle actually taught that it was a perfect sphere I mean we can all see that there are different colors on the moon bits are dark and bits are light but Aristotle said that really didn't matter it was still a perfect smooth sphere well as soon as you look at it through even low resolution binoculars you can tell it's not there are shadows there are mountains there are walls this is not a smooth object this goes against Aristotle but again the Jesuits at this point we're excited by this and here's something that was even more profound there were these four little stars around the planet Jupiter and nine tonight the little stars changed positions you could actually sort of see that there was a cycle to the way they changed could it be that something was orbiting the body other than the earth yeah so these these four little stars are orbiting around Jupiter they didn't know they were moons they just knew there were tiny little stars and this was very interesting because the earth is the center of all rotation if earth is the center of all movement how could this be so this was beginning to break down the idea that the earth was in the center so here we have sort of a I believe this is a 20th century idea of Galileo showing his observations to very skeptical Cardinals it wasn't quite like this I mean I mean Galileo at the time was getting fans he was very very popular in the court he was became an incredibly popular figure because of this book there's some scans from the original last Darius Nokia's of these little stars changing position night tonight okay now here's something that's a little bit less talked about but it actually proves that the Aristotelian system is wrong it actually was the nail in the coffin and that was the phases of Venus Venus if you look at it through a telescope goes through phases like our moon it actually is full some of the time and crescents some of the time okay that's kind of neat but why does that prove that the earth is not in the center well look what happens when you actually compare the two models okay here's here's some observations just to show you these are actually pictures taken in 2002 of Venus Venus when it's close to us why shouldn't say didn't know that at the time it's when it's Crescent it's very large when it's it's full it's very small so it changes shape and it goes through phases okay this diagram is a comparison of the two systems let's start with the Earth centered system which is over on your left in the Aristotelian system people had observed that both Mercury and Venus stay pretty close to the Sun you see the Sun in the sky neither of those planets gets very far away they kind of cycle back and forth so Aristotle said there basically is a line connecting the earth to the Sun and these two planets orbits centered on that line so if that's true picture that you're on earth and you're looking at Venus that means the Sun is always on the other side of Venus Venus is always closer to us than the Sun so as Venus cycles around we only see it in the crescent phase we never see it as full because to be full it has to be on the others side of the Sun when your astronomer you use these diagrams do people see this people see that that's the case and in the in the sun-centered system you can actually have the earth and Venus on opposite sides of the Sun very easily they're just in different parts of their orbit around the opposite side of the Sun but in the Earth centered Aristotelian system you couldn't have that that was it okay Aristotle system is now proven to not be correct he went on to do other observations too obviously some people at this time are beginning to get a little worried about it and we'll talk about that later he did observations of sunspots and this has to be one of the that's a very strange-looking woodcut of Galileo he's got this big smile on his face like I said this was a courtier a person who liked to promote himself somebody who was very interested in public attention and he's smiling there so like a used car salesman or something I mean I've I've looked at this woodcut many times and I just I can never take it quite seriously interestingly enough again Galileo was not the first person to observe sunspots there are several records we have there seem to be some very old Chinese observations not very well documented Kepler actually saw a sunspot in 1607 what he projected the Sun through an instrument but he thought it was mercury that was a planet but we actually know now it was a sunspot mercury wasn't at that point in its orbit when he made that observation Galileo and Harriet we talked about James Herriot before and also a Jesuit astronomer named shiner all were observing sunspots around the same time interestingly enough the first people to publish them we're a father-son team named David and Johannes fabricius and they published about them in 1611 and they correctly thought they were spots on the Sun so they people knew about this this is actually shiners work this is shiners apparatus of projecting the Sun through a telescope onto a piece of paper and these are his observations of sunspots now Scheiner thought that the Sun was still perfect and these spots must have been maybe little little moons orbiting very close to the Sun but Galileo really Lambay stood that idea and said if you actually think about it it's pretty stupid that'd be right on the surface of the Sun so there's a there's a neat series of drawings the Galileo made of spots and he oriented the Sun the same way on each page and the same size and if you do a time-lapse of them you see something very interesting we just play this animation okay that's a time-lapse of Galileo's drawings one after another and you can see that the same series of sunspots move their way across the Sun and they even sort of they even sort of distort at the edges like they're going around when you look at these drawings one after another do you get the impression the Sun is rotating yeah so an incredible idea that the Sun itself might be rotating and these are actually on the surface of the Sun Galileo was not real friendly with shiner about this I mean he lambaste it and called him a fool so astronomers all over Europe were really sort of risking the wrath of Galileo if they'd said anything about them being wrong this was making him unpopular and trouble was beginning to brew not just in academic circles but also religious circles the two are probably combined remember most of the academic astronomers at this time were also Jesuit priests so when they got pissed off by Galileo one of the things they could do was grab the church authorities and say hey this person's causing trouble one of his patrons his great friend was the Archduchess Christina this was the mother of Cosimo and Christina wrote to him and said I'm worried I'm hearing that you are saying things against the Bible that may be heretical and Galileo wrote back what has to be one of the most incredible defenses of observation and rational thought that I've ever read I don't want to take a whole lot of time but I do want to read a couple excerpts I won't read all of these but don't worry about reading them I'll read them to you but the idea that God is known first through nature and again by doctrine by nature in his works and by doctrine his reveal world I love this list this next one I do not feel obliged to believe that the same God who has endowed us with senses reason and intellect has intended us to forego their use and by some other means to give us knowledge we can attain them he would not require us to deny sense and reason in physical matters which are set before our eyes and minds by direct experience or necessary demonstrations this must be especially true in those Sciences of which but the faintest trace and that consisting of conclusions to be found of in the Bible of astronomy for instance so little is found that none of the plans except Venus sorry I lost my place penises so much is mentioned and only once or twice by the name of Lucifer if the sacred scribes had any intention of teaching people certain arrangements and motions of the heavenly bodies or they'd wish us to derive such knowledge from the Bible that in my opinion they would not have spoken to these matters so sparingly we can read more but Galileo was basically saying and this is actually from the letter this is not just something kind of cute that he quotes a clergyman is saying those truths here we go the intention of the Holy Ghost to teach us how one goes to heaven not how heaven goes right the Bible doesn't teach us astronomy the Bible in immediate Galileo actually says the people who wrote the Bible decided not to do this at all it's not the place of the Bible to teach us things we can observe directly there are two ways to know God as an astronomer at NASA I've often been asked to comment and to talk to people who believe in evolution versus creation I was actually sent to the Kansas School Board to talk to people about this they'd like to send people that are friendly and kind of non-threatening and I try to be that but one of the things I said to them you know remember there was a time when the earth being in the center what was it was a capital offense knowledge has changed and it has been uncomfortable for humans to sometimes take that change but the idea that God would give us observations and not allow us to believe them there are two ways to know God there is nature and there is scripture and when there appears to be a disagreement we're observing something in nature that doesn't seem scriptural it's human error that causes that it's not God it's an error and interpretation of what we think God may have said I was called the handmaiden of Satan for that that's one of my favorite monikers actually anyway speaking but back to the story now unfortunately one of the people that really was getting a lot of complaints about Galileo was the Grand Inquisitor and this is a very interesting person not a simple person not a person who is just a slathering dogmatic monster um Cardinal Roberto Bellarmine it was a very intellectual person he was the Grand Inquisitor and he actually was from the Netherlands which at this point was becoming Protestant more and more and he was and he was actually born in one of the last bulwarks of Catholicism against this in cringing Protestantism and he was a huge fan of Thomas Aquinas of reason and of Aristotle and he tried to reason with heretics he actually published a famous letter called disputations about the controversies of the Christian faith against heretics at this time he drew on Aristotelian logic for this and the teachings of Aquinas he was a very reasonable person he lived a simple pious life interestingly enough we have on record that for a while he liked to study astronomy but gave it up because of the dangerous thoughts it was creating fear very interesting so trouble was brewing Galileo had made a lot of enemies and one of the things that happened is people started preaching against him from the pulpit that was not a safe thing to do Galileo had the patronage of the Medicis so in 1614 there was a priest named Tommaso Cassini and he preached against Galileo one of his superiors had to apologize to the Medicis for that so at this point Galilei was still very well protected by the Medicis so in 1616 they actually decided to rule on Copernicus Copernicus at this point they knew he was heliocentric they knew that that wasn't Aristotelian but the Catholic Church had not felt it necessary to come out and proclaim Copernicus a heretic in 1616 they did so that was the first time and really this had to do with the politics of Europe the Protestants and the Catholics fighting they had to come out with a stand I just want to tell you a little bit about one of the things that Cardinal Bellarmine was involved in was the persecution of GR Giordano Bruno it turns out to is the 400th anniversary of his death today February 17th this was somebody who advocated the son being in the center he also believed that the stars were Suns with worlds around them himself he actually was kind of an itinerant priest he got kicked out of many monasteries for his beliefs joined the Calvinists the Protestants for a little while ended up in dub in France I Galileo and Bruno's paths had to have crossed he tried to get a teaching job at Oxford but then he tried to go to Padua and the chair of mathematics went to Galileo instead of him so this was sort of a contemporary a little bit of a competitor of Galileo now it's worth mentioning that when they actually executed Bruno they had not ruled on Copernicus yet Bruno was probably not executed because of his beliefs in heliocentrism those were bad but he actually doubted the divinity of Christ and the virgin birth and believed the universe had no center and these things were much more important to the Catholic Church than heliocentrism but anyway they burned him at the stake 400 years ago today okay it's a good question and I I don't I don't know in their bed that probably makes a pretty significant difference so yeah okay so things are going badly for Galileo he was still protected by the Medici z-- but then something really good happened an old friend of his was elected to be Pope this is Pope Urban the eighth Maffeo Barberini that's an actual portrait on the right side by Caravaggio of him and what the woodblock print on the other side he and Galileo were longtime friends that we have many letters between the two of them this was not a particularly dogmatic Pope he was more known for nepotism maybe very controversial nepotism than he was for Dogma and one of the more famous things he did was he actually melted down these big Roman bronze beams in the the Pantheon to decorate st. Peter's with and that actually caused the wonderful quote that basically quote non-veteran Bob re fecund Barberini which means what the barbarians didn't do Barberini did so things that had survived even the barbarians coming through rome Barberini was melting down to decorate st. Peter's but at any rate in 1623 Galileo went to visit his friend and they walked together in the garden we hear about this from Galileo's writings and they talked about this I'd of heliocentrism and basically the Pope said you are fine to teach it as long as you teach it as a theory you don't have to say whether it's true or not we're never gonna know which one is actually real he also said that God can make the world appear any way he wants to this is kind of platonic the idea that the natural world is perhaps corrupt not perfect and if God wanted to make the world appear away even though it wasn't really that way then he could it's actually a fairly sophisticated argument so at the time he had a friend in the Pope somebody who was familiar with him somebody who was protecting him and Galileo felt that he now could really start to talk about heliocentrism this is when he wrote a number of things that again began to make him more enemies one the first things he wrote under the patronage of the Pope was something called the assayer and the assayer was a neat little note that unfortunately really reamed down on the jesuit astronomers the jesuit astronomers had observed a comet earlier that year and by using parallax they proposed that the comet was much farther away than the moon but galileo knew that comets were atmospheric phenomena they're just in our atmosphere and he wrote a letter just lambasting these Jesuit astronomers calling them idiots now comets are farther away than the moon so in this case the Jesuits were right you know more bad remarks about shiner more bad remarks about professors there was a controversy about floating objects and how they follow the rules of Archimedes more than Aristotle at dinner conversations at court events that this person was picking arguments so the personality of Galileo seems to be kind of getting in his own way here he was actually warned that there was a thumb in something there was a painter who warned him that something called the pigeon League in quotation marks in or I don't really know what that means was out to get him and they would use his heliocentrism if necessary as an excuse so even people were out to get him at this point then he did something which honestly I have not really been able to understand he published this work at an incredibly well-written wonderful book called the dialogues on the chief world-systems however in it he basically made fun of things the Pope it's very directly and very recognizably what it is is it's a conversation I mean think about this this is a scientific text that usually written in Latins was written in Italian and instead of it being a very formal book it's a conversation between three friends about which of these world systems must be true is it the geocentric system or the heliocentric system and it plays out over a number of days now obviously Galileo was putting the wise words into the mouth of the character that said that the Sun was in the middle the person said the earth was in the middle was actually called simply kyo the simple one and there were quotes that directly were recognizable as things the Pope had said so the Pope may never have read this book we don't actually have any record the Pope read it but people sure showed him those passages and told him that Galileo was making fun of him now an unanswered question is what was Galileo thinking couldn't he have couched this a little bit more politically couldn't he have done this a little bit more gently but at the time this was in fact the straw that broke the camel's back I mean this one work alone might not have done it but after heaping disdain on the astronomers pushing the political boundaries it snapped and they brought him to trial before the Inquisition so he was found vehemently suspect of heresy three Cardinals out of the ten abstained actually so they're not everybody voted against him the dialogues were banned and and they were just you're not allowed to have a copy on pain of jail I think the dialogues were finally the Catholic Church finally lifted the ban in 1835 by the way and we were talking a little bit before we may have a chance to talk afterwards pope john paul ii did try to get some sort of forgiveness of galileo and i've been told that the subtlety is that he was never actually forgiven but there's some sort of dispensation which we can talk about but in 1992 they did I think at least let him out of hell according to so Galileo was arrested they threatened to put him in jail for life there there is some evidence that he was shown the instruments of torture and said if you don't recant your belief this is what we're going to do to you and at that point I think very wisely he recanted publicly and said no you know that the earth must be in the center there's there's the wonderful tale of him possibly saying as they do aggghhhhh dim away you know but it still moves he may not have done that I wouldn't do that before the Inquisition he was put under house arrest that was actually a bit of a milder sentence they did threaten him with prison for life the Florentine officials intervened and got him under house arrest so he stayed under house arrest for the rest of his life he was allowed to have pupils and he actually did some non controversial things like laws of motion I'm going to be a little conscious at the time here because I think people probably at places they want to get I would love to talk to you a bit more about the laws of motion because he actually observed some incredibly profound things the idea that a pendulum in a pendulum swings the period the time it takes doesn't depend on how the amplitude how far it swings but just on the length of the pendulum it's not a weird idea so think about a big pendulum and you make it to swing a little bit it takes the same amount of time as if it were swinging a lot the time of pent nobody ever noticed that before amazing the idea of acceleration that the dropping balls you know the balls actually probably were never dropped from his hands because too hard to measure when they actually hit the ground this is actually a reconstruction of an apparatus where he timed the balls rolling down a slope and timed very accurately what the acceleration was to determine there was no difference between the two balls and then 1642 he'd gone blind he complained of heart palpitations he was never in particularly good health during his imprisonment and then he died he's buried in this I've actually visited his grave in Florence interestingly enough he's buried with his daughter maria celeste and that's the only other person who shares his grave so the two were affectionate to the last she unfortunately died young she lived to be 33 years old and so he actually lived past her but the two are buried together so let me just end then by saying that as an astronomer you know we honor Galileo in many ways I love the fact that we actually did end up naming the moons of Jupiter after him these are the Galilean satellites not the Medici and stars these are the four largest moons of Jupiter that they're actually worlds unto themselves it's worth noting these are not the only moons this is actually an animation of the moons of Jupiter the major ones here the Galilean ones are named we're actually going to pan out look at all the different moons that there are so those are the major ones we know of but I'm losing track I think we know of over 70 Luna's that we track the orbits of around Jupiter so there's some other ones they're going farther out yeah there's a lot more moons of Jupiter than you might know but the Galilean satellites are the largest of the moons of Jupiter I think are we oh yeah here's actually they're their worlds unto themselves this is a picture of io io is the most volcanic Li active body in the solar system and those are iOS Northern Lights you're seeing see that little glow there those actually the Northern Lights on Io another one that there's IO again incredible thing I mean it's actually yellow because of sulfur and huge volcanic explosions going off all the time Europa is one of the places where NASA is going to look for life there's very interesting suggestions that there might be life underneath this ice there's liquid water underneath the surface and not only is there liquid water when you look at the cracks it's got some interesting chemistry there some organic compounds in it there's some neat stuff welling up through the cracks there may be life on this moon this may be the first place we find life and of course we named the Galileo satellites and Jupiter Observer after Galileo so in conclusion Galileo to me is a very recognizable figure I admire this person so much and his ops gay idea that observation Trump's philosophy we have to observe the natural world even if it doesn't fit with what we're comfortable with with what the church says science and theology are separate there is no need for them to get into arguments with each other the idea also of self-promotion I mean I mean I was taught as a graduate student if you don't publish it it doesn't exist you publish you get things out you make yourself known I have not done active research for the last ten years my full-time job is public outreach so I'm an astronomer employed by NASA full-time I'm the assistant director of science at Goddard but my full-time charged to make sure people like you are getting some of these messages and also this wonderful story of personalities patronage politics science always was like this I'm sure back to Aristotle but it's so wonderful and obvious the way things went right and wrong for Galileo it's an incredible story the sheer brilliance of this person inspires me today and I'll end I'm actually going to just sort of bring this microphone down I'm going to show you a wonderful little honor to Galileo they did on the moon for Apollo 15 you've heard about the the reason you drop two balls and they fall down at the same time is that the acceleration of gravity doesn't have to do with something's mass and somebody people will say okay well how about a hammer and a feather they don't fall at the same time well that's because the feather has you know air resistance and kind of floats down so this was done on the moon they used a hammer and a feather and here's the astronaut thank you very much this has been a presentation of the Library of Congress visit us at loc.gov

Channel: Library of Congress

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Id: zSZN8eIb_hI

Length: 65min 50sec (3950 seconds)

Published: Wed Mar 28 2012