saw them we have our beautiful beautiful pictures tonight special request by our speaker that you have the core of the globular cluster Omega centari okay and all these beautiful red and blue stars which are actually ultra violet and infrared as well as visible light it covers the full spectrum with Widefield camera 3 it's it's beautiful um more details available on the back and I hope our speaker will actually talk about that a little bit tonight who is our speaker our speaker is Mia boville she is going to talk to about the Harvard computers and the classification of stars of course this was work done a century ago so computers is in quotes and you'll understand that in a bit next month I've been having trouble getting people to commit to June usually July is my problem okay but I've had people tring so it's still to be announced but I'm working on it trust me I'm working on I'll find somebody's arm to twist for next June June 6th uh July is actually been moved early because we have Amber stra from Gard space flight center here and she will be talking on Dark Energy in new Worlds the science that is we hope to accomplish with NASA's W first mission uh that will hopefully launch uh sometime next decade um there will be no lecture in July because we're taking Amber's lecture and counting that as our July lecture in August I have a really cool talk for you uh the view for Mission operations that's not the title I just made that up this afternoon she hasn't given me a title but courney MC mcmanis who has worked on Mission operations for the International Space Station um and we're talking we have the missions oper uh operations here for jdst here in the building she'll be telling you all sorts of cool stuff uh from Mission operations standpoint August 1st 2017 uh can't remember all that you can go to our website on Hubble site and by the way hubblesite has been uh design has been changing I don't know how many of you go to our Hubble site website but we've been changing it and modernizing it all the content is still there okay you can still find us uh finding this B page is probably the easiest if you go to your favorite search engine type in Hubble public talks you'll find this web page on the web page we have our links to our live webcasting uh links to the archive all the way back to 2005 in the stsci webcasting archives as well as a way to sign up for our email list to get our couple reminders a month about the talks that are coming uh the announcements again T sign up at the website but if you want to do it the hard way you can go to mail list. stsci doedu the mail list is called public lecture announce uh if you would like to ask us questions send us comments uh you can send email to public lecture ssc.edu for those of you who like social media Hubble has several ways of communicating Facebook uh Twitter feeds Google+ and Pinterest out there for those of you who use those social media myself I have a Blog on Hubble site I have Facebook Google+ and Twitter that I occasionally do uh but unlike the president I have better things to do with my time so I have a tendency to do my science rather than spend too much time on Twitter okay uh Observatory tonight yes the weather is permitting I talked with arini um and she should be here about nine o'clock or so to take a group across the street to look through the telescope across the street so at the end of the lecture if I forget somebody remind me um you'll meet down here with arini and she'll take you across the street all right um and now okay my section news from the Universe for May 20177 our top sto first story tonight by Jupiter it's quite a beautiful planet um Thomas can we take the lights down a bit there's a little bit of spillage onto the onto the um screen here okay that's good thank you all right so uh every once a year Jupiter gets into a what's called opposition okay where the Sun and Jupiter on the are on the opposite sides of Earth well this is the point in Jupiter's orbit when it is closest to Earth because you can see that if it were located anywhere else around its circle around its orbital Circle um it would be further from Earth so the best viewing uh its closest point is at opposition also it's its best viewing because it's up exactly opposite the Sun so it's not not not up at Suns set not up at sunrise where you have interference of that um and you can see it now Hubble doesn't have to worry about that too much because Hubble can doesn't have to hubbles up in up in space and it doesn't have to worry about you know daytime versus nighttime because you know it doesn't have the atmosphere to look through however we often take pictures of the planets when when they are at opposition and you might think to yourself well we've had missions that go to the planets what can Hubble offer and I sometimes look at these these press leaves we do and go okay but you know what oops um well on let me replug you know what this is an observation we have yet to take let me try this again there we go okay there we go now we got it we're back great um but you know what sometimes we just get it right so this is our picture of Jupiter at opposition from uh this year Isn't that cool I mean I remember when we had to have the Voyager missions to go across go across interplanetary space to get something that looked this gorgeous and I just love all of the hydrodynamic effects okay um I'm a sucker for for all the hydrodynamic effects of the the vortices and the swirls in in Jupiter's atmosphere plus you'll notice we've got not only the great red spot but also we have what we colloquially call Red Spot junr officially called oval ba I much prefer red spot Jr and red oval ba formed in the year 20 000 okay we had never seen a second red spot until it actually well it formed as a white red white spot and then turned red a few years later but it has now been around for almost 15 15 20 years okay so we're seeing a second Red Spot on Jupiter and it appears to be long lived but I just thought this was a really wonderful uh a beautiful image of Jupiter our second story tonight is also from the solar system europa's Old Faithful all right so first of all let's make sure everyone remembers what Old Faithful is Old Faithful is the Geyser in Yellowstone National Park that erupts approximately every 90 minutes is that right is that about 90 minutes or is it longer than that yes Karen's W saying yes which is actually incidentally about the same time it takes orbit Hubble to orbit around Earth so every time Hubble passes over Old Faithful erupts right not quite um and so this is a Geer from Hot Springs okay um and so the idea is that the water spews up 100 feet in the air or so right well if you remember if you were here last year I told you about seeing a plume on Europa that spews out a little bit further than 100 feet all right so you got to understand this image okay first of all um the plume is in white which is really pulled out of the data it's really hard hard to see this it's actually seen in Shadow against the the surface of Jupiter so Europa is passing in front of of Jupiter and we're seeing that plume in Shadow it's been reversed here so that you see it as white and then the picture of Europa here is not from Hubble this is actually from the Galileo Mission all right as remember I said we get missions that have been there they got better pictures so to give you an idea of what we're seeing we've taken the Hubble data stretched it in contrast so you can see see the plume because it's really tiny there um and then thrown the Galileo image on top of it okay this is what I told you about last year Well we looked again to try and see if this was a recurring event and yes it is we are seeing another plume now we don't see it every time we look for it okay we have done this observation multiple times sometimes we see it sometimes we don't which gave me the sort of uh instance of Old Faithful that it sometimes erupts and sometimes doesn't what does this mean well the surface of Europa if you look at it in detail resembles cracked ice rafts on uh uh in the Arctic this is actually the surface of Europa and you can see all the IES and all the cracks in it okay all right and when we're because we were able to time when it uh when we saw this plume and where it was on on on the on the moon we're able to narrow down to where we thought the plume was coming from to these cracks here on Europa all right and the idea was to say all right why would these cracks be emitting uh water vapor Well turns out that a temperature measure of the surface of Europa shows that that area is 3 degrees warmer than the rest now you have to recognize 3 degrees warmer is going from 92 Kelvin to 95 Kelvin and this is an absolute scale so this is minus a couple hundred degrees Fahrenheit okay so when I say warmer I really should be saying 3 degrees less totally absolutely frigid okay um but they it is actually warmer so the idea behind all this all right the idea behind our understanding of Europa is we have understood that underneath its icy surface there is probably a liquid water layer now originally we thought that that icy icy crust was about 100 kilometers thick and if you wanted to sample the water you'd have to drill down through 100 kilometers which is not a very easy task however if we're seeing these plumes and we're seeing them more than once it may indicate that there are pockets of water maybe not the ocean underneath a layer but maybe there are pockets of water that just a few kilometers down in the ice if you remember what we learned about Pluto last year C biot tectonics is really much more important in the outer solar system than we'd really understood so we learned that also about Europa that the I move and crack and and and the the the Dynamics of IES um is a lot more than we had previously suspected and in perhaps there are pockets of water that are one two few kilometers down then that raises the prospect for being able to go there drill down to it or melt down to it and be able to sample it now why would we care about water well because there are three things required for life in the universe as we know it one is carbon carbon's everywhere two is a source of heat we got sources of energy all over the place and three is water so our search for life in the universe is often just boiled down to a search for water wherever liquid water can exist perhaps life can exist and we seen life in all sorts of extreme places here on Earth so Europa is one of our strongest candidates for possibly having life elsewhere in the solar system and the observations from Hubble have done yet another small part in convincing us that hey this is a really cool system we ought to continue to investigate it and yes it's become one of our main um uh points of study for trying to under trying to to look for life in our solar system all right third story tonight our 27th anniversary perspectives on spiral galaxies the 27th anniversary is of this event the launch and deployment of the Hubble Space Telescope it has been 27 years isn't that great all right we've been up there for 27 years doing science and so every year they ask us to do a really cool uh image for the 20 for for for the anniversary and it's I got to say um one of the gentlemen who CH helps choose these images is in the audience right now and he can confirm that it's really really hard to keep outdoing them themselves every year so this year we chose some spiral galaxies okay and these spiral galaxies are in the Virgo cluster so we're going to zoom in from a Widefield view we're going to go keep going down and going down and zooming in until we come into these two two spiral galaxies NGC 4302 and NGC 4298 such wonderful names and those are the two spiral galaxies we chose uh for the Hubble 27th aniversary image now if you notice at the end of that movie it zoomed in in visible light and then switched to infrared so let me show you those in detail here is the Hubble image uh using visible light all right and this is the infrared view all right using the uh the the in the near infrared capabilities of Hubble so visible light infrared light and you can see that you can the the the difference in how we view the galaxies changes according to the wavelength in which we view them well we also wanted to give you another perspective on them so we created this visualization to help you understand the shape of these spiral galaxies and so by rotating those galaxies in 3D by the way those those are just computer models of the galaxies we don't know the exact details matter of fact the Galaxy on the left NGC 4302 um the model that we used is a model based on the Galaxy M51 the whirlpool Galaxy because we're seeing that Galaxy Edge on we really can't tell the true threedimensional structure so we had to use as I like to say a stunt double Galaxy for it um but that gives you a mental model of what you're seeing in this image and when I show you another image which is also in the Virgo cluster I show you this image of all these various spiral galaxies you now have the mental model in your head to interpret this and say okay these are all pretty much those same dis shaped galaxies but seen at different angles so in doing this you gain a mental model of of how Spyro galaxies look and you can see them in perspective you can translate images such as this all right and now it's time for our featured speaker uh Mia boville uh Mia is been here at the Space Telescope Science Institute for only a year and a half uh she gave a wonderful talk last year and I'm really looking forward to her talk this year she got her bachelor's and her F her Masters bachelors and her PhD from the University of Maryland physics um she spent a year at the University of Texas at Austin before spending three years uh down in Chile at some unpronouncable Institute in Santiago she said she'd pronounce it for you she wouldn't make me try to pronounce it um she came here and her she does her research on dwarf galaxies as she likes to say the smallest of the small galaxies um generally those in the nearby neighbor nearby universe or those in the very distant Universe she doesn't care about the 10 or 11 billion light years in between she also would like to note that for tonight uh she's doing a talk on the women from Harvard and uh when she was an undergraduate she did a research experience for undergraduates at Harvard uh working on of all things Star formation so ladies and gentlemen our speaker tonight Mia [Applause] boville can you hear me okay um and it's ins University at cathol Chile I wasn't going to make him do that again um when astronomers talk about the Harvard computers we actually don't put quotes around them um this is this is an image of the Harvard computers it is a group of women it is a group of women that worked at the Harvard Observatory over the course of about 40 years they generally stayed for 10 20 30 years and up until the 1920s this was the only place where you could be a woman and a professional astronomer other than some of the women's colleges like Vasser which has had Mariah Mitchell but what did they do that was so incredible and before I get into that the scientific parts of this story and their contributions to astronomy are so fundamental that you learn about them in your very very first year in fact you learned about them an introduction to astronomy for poets but the human side of this story and many of the quotes that I'm pretty much all the quotes that I'm going to be using come from this wonderful book that just came out called the glass Universe um this is the same author that um wrote Galileo's daughter in longitude and if you're interested in hearing more about this story as well as many of the players that I'm not going to have time to talk about tonight I highly highly recommend that you read it so if any of you you cannot see this from Baltimore many for if any of you have ever had the wonderful opportunity of being in an extremely dark sky you have this lovely view of the disc of the Milky Way galaxy and when you take that into three dimensions I'm afraid that my visualization is not as good as the one you just saw I went for the cartoon version you have this is that thin disc that you saw in the animation in the center of most spirals is a bulge surrounded by a Halo of stars I can tell you that in this dis are open clusters these blue objects here these are regions that are either still forming or more very very recently formed stars in the outskirts of the Galaxy are globular clusters these are old systems they're 10 12 billion years old so roughly appro approaching the time that I'm interested in how but how do we know this we look at we can observe clusters like the pleades which I'm sure if you ask very nicely and it's up they'll be willing to show you tonight you can see this by eye the seven brightest stars are visible by eye in the constellation of Taurus even from Baltimore this is about 25 this is an open cluster that is about 25 million years old and you can see some of the gas here that's still surrounding the stars or this this is very very recently formed Stars this is Omega centor this is zoomed out quite a bit from the Hubble image that was handed out this is a globular cluster it's one of the younger globular clusters some of them are billions of years older than Omega centor and so here is a question how do you find out the age of a star you can't ask it it would not only be rude but I don't think you would get an answer and the answer to that is you use one of the most powerful diagrams in astronomy which are color magnitude diagrams or HR diagrams this is the Hubble image that you all have there was a reason that I asked for it and this is an animation we're going to take the stars of Omega sen and we're going to zoom in a little bit this is the very core of the cluster so there is an incredibly Dense Star field those stars are then going to be sorted The Bluest and hottest stars are going to move to the left and the coolest and reddest stars are going to move to the right you're now going to sort them by absolute brightness or Luminosity the brightest stars to the top the faintest to the bottom this is the HR diagram it is one of the most powerful plots in astronomy in fact I would tell my astronomy for poet students you understand this you're going to pass the Stellar Evolution section of the class I called it their cheat sheet along here is the main sequence our sun would sit about here if it was an Omega Sun all the stars and it's now I have a better one coming up did you notice that it turned off the main sequence didn't continue all the way up it turned off that is how you determine age this is a more cartoon version for expl explanatory purposes here you have the main sequence all the stars here burning hydrogen in their core and the more massive you are the hotter you are you can think of these guys as Hummers and these guys as Priuses you're also these are going to be brighter they are hotter and they also burn out a lot faster so if the main sequence turns off here your cluster is about 10 million years old if when you plot up your main sequence it turns off here it's a billion years old once a star turns off the main sequence it moves up through the Giants or into the Super Giants and eventually evolves down our sun will become a white dwarf objects that are a little more massive kind of hang out here for a bit they can't quite decide where they're going to sit and then they blow up in Supernova this is on the Y AIS the vertical axis we have Luminosity or absolute brightness you're going to hear me use those two terms interchangeably they mean the same thing and what this entire talk is about is this x-axis it's in color from red to blue it's also in something we call the spectral sequence and we also temperature increase to the left and how and the fact that I'm able to tell you that is because of the Harvard computers so we need to go back a little bit before 1880 this is the refractor at Harvard these are not reflectors modern telescopes are reflectors you have a mirror at the base of the telescope the telescopes that were used to produce these observations are refractors they have a lens at the top of the long tube they're much larger for the same size telescope it's why we stopped using them at the time in the 1870s and 1880s there was this new fangle thing called photography I don't know if any of you have ever done this for the younger people in the room there was a time when you took a picture with a camera and it was on film and you had to get it developed you didn't just take it with your phone and put it on Facebook or Twitter or SnapChat or whatever the hell the newest thing is they took images not on film but on photographic plates this is a digitalization a part of the Palomar Sky survey this is an actual physical glass plate some of these could be about that big so they were heavy they broke and just not the best option but this was all we had until about 30 years ago and each of these points is a star in general the big the bigger the star the bigger the black here this is a brighter star than that so you can tell the magnitude of the star and if you take this image in red and red and green and blue filters you can also tell the color of the star which is how the HR diagram was originally plotted but we want more information welcome to astronomy this is Henry Draper and his wife Anna Draper he was a medical doctor who had an astronomy habit she had the money and he developed a method for taking that Spectra for taking this plate and he stuck a prism in front of it so actually this is one of this is the best graphic I could find on the internet for this I'm not actually kidding you have your light from a distant star you pass that light through a prism and breaks it into its components and when you break that light into the components you get a lot more information than just the color of the star this is the spectrum of the Sun so you look at the sun you see a yellow star we call it a g-type star all of these black lines are absorption lines and each element has a unique set of absor aborption lines they think of them as fingerprints you can identify a human with their fingerprints you can identify an element or a molecule by its Spectrum the simplest of these is hydrogen so up here is wavelength in angstroms that's about that's one 10 that's one just a second one 10 the so each of these numbers multiply by 10 the 10 so 10 addition Zer will get you um met so this is one in 10 10 met very very tiny scales H Alpha H beta H gamma and H Delta H Alpha is actually one of the most important lines in astrophysics the more complicated the element As you move up the periodic table the more complicated it's Spectra now the plates Draper took didn't look like that this is um um one of the Draper plates at the location of each star you see a Spectra in the initial set of plates each of these was one inch across so if you hold your fingers at about an inch that's how wide each of these things was on the glass breakable plate unfortunately reasonably quickly after discovering this method Henry Draper died um as was IAL of I think the entire 19th century he caught a chill and had a dinner party and went to bed and never got up and Anna Draper was so devastated by her husband's death that she wanted a memorial to him so she talked to Edward Pickering and endowed the Harvard Observatory with money to finish her husband's work and build a Henry Draper catalog of the stars because remember she had the money and Edward Pickering did something that the time even Anna Draper wasn't expecting he felt that women would be well suited to the repetitive and drudgery of looking through thousands and thousands of glass plates with Spectra that are inch wide now years later of course you tend to sugarcoat this and you talk and he talks about the criticism is often made by the opponents of higher education of women that while they are capable of following others as far as men can they originate almost nothing so that human knowledge is not Advanced by their work keep in mind this is 1880 this reproach would be well answered if we could point to a long series of such observations as are detailed below made by women observers this is the first this is one of the first times in history that women are making contributions and pierine acknowledged the Harvard computers in their work the first of the Harvard computers was Willam Fleming she was a Scottish immigrant who moved to the United States got pregnant and her husband promptly left her so she got a job as the maid at the observatory Residence at Harvard and pierine knew her he was the director of the Harvard Observatory at that point he recognized that she was a little too intelligent to be a maid she didn't have a college degree but she was educated and he hired her as a Harvard computer in in as a computer in 1879 I'd like to point out the other reason to use women they're PID lless I didn't know if you've heard about that um she promptly leaves a year later to give birth to her son in Scotland and then leaves him with her mother and her aunt and returns to Boston without him in 1881 I think he he eventually makes it to the United States but it's like 10 years later and her task was to classify these Spectra so if you remember this is what she's looking at through magnifying glass and she noticed that here is good old hydrogen good old hydrogen Alpha she noticed that some Stars had stronger hydrogen lines than others and so she classified them by the strength of their hydrogen lines the strongest hydren line she gave called a Stars the next b c d you can see where I'm going um all the way down the alphabet and you'll note that this is not an alphabetical order and we're going to get to that in a bit she also discovered variable Stars she found one of the first Nova because they're looking at a set of plates that no one's ever had before and in General in astronomy when you have a technological advance and insane amounts of telescope time discoveries happen but later in her career and for the last about 10 year 10 to 15 years that she was at the observatory her primary Duty was to curate these glass plates these are irreplaceable you don't have digitalization you don't have a dig you don't have a phone you can take out and you know take a picture in case you mess up if something happens to these glass plates the information is lost forever she was also responsible with editing and preparing the dra Henry Draper Memorial catalog for publication there are 90 volumes of this so she also was the effective head of the Harvard computers their leader as you will but unfortunately I love astronomy everyone loves astronomy I need to pay rent and P and this is a wonderful quote Pickering seems to think that no work is too much or too hard for me no matter what the responsibility or how long the hours but let me raise the question of salary and I am immediately told that I receive an excellent salary as women's salaries go because of course if you're a woman your husband's actually making the money and in general the Harvard computer were unable to live completely independently many of them lived in boarding houses or rented at rooms in their own homes to make end meet because remember they could be paid less than a man or cheap um Antonia Mari was actually the first Harvard computer she was related to Draper and she was the first Harvard computer to actually have an astronomy degree and that degree was from Vasser which is where Mariah Mitchell worked and remember what I said about technological advancement well instead of having those Spectra be an inch wide the plates that Mari got to work on they were 4 Ines wide and they were far far more detailed and you would think detail is good detail is generally good but complicated and she noticed that in addition to the lines having different strengths so having different having different depths some of them also had different widths two stars that seem to have the same strength of hydrogen line would have different widths of hydrogen lines and she worked to try to incorporate this into a new classification scheme so she threw out what Willamina Flemin had done with the alphabet and came up with a numbered scheme and this worked but it was actually a little ahead of her time and so now we get to the three main players in this little drama they're on my shirt if you need reference um Henry Henrietta Swan lit and Annie Jump Cannon arrived at the same time as unpaid interns for a year both of them then left and were only able to return when another one of the computers got married she had a degree from Radcliffe which no longer exists because Harvard now lets women in and she was also deaf not her entire life but in adulthood and she was given the task of monitoring variable Stars so you can imagine you've got all these photographic plates and you're going to see certain Stars vary a little bit in brightness so you're literally looking at this plate and then this image from two days later and two days after that and she came up with a novel method that allowed her to look at one plate on top of the other using a negative image of one and putting the positive image of the other on top of it and down the line she found she was looking at a set of variables in the LMC here's a very pretty image it did not look like that on the plates and she found a class of variables that were already known called seids and the characteristic of a seid is it rises very very quickly in brightness and then falls off slowly and then Rises quickly again and falls off slowly and because all of these seids were in the large medulin Cloud she knew that they were at about the same distance from Earth and so if one of those seids appeared to be brighter than another it actually was brighter than another and she plotted this as you do in astronomy you plot things and she found that the longer the period of the sepid the brighter the the brighter the sepid actually was and you can see this here the brighter seid with its longer period and the fainter seod with the shorter period this was immediately recognized for what it was this is called a standard candle this means you can look at a seid you can measure its period and you know how bright it is and if if you know how bright it actually is and you know how bright it appears to be you know how far away it is this was used within a year of her Discovery to find that the LMC and the SMC were just a bit further away than they thought they were and in actuality they're even further than that this is her and Henrietta leave it and Annie Jump Cannon um about sometime in the teens in front of the Harvard Observatory they came in together as interns Annie Jump Cannon arrived because there literally somebody got married so she was hired she graduated Val Victorian of Welsley in a degree in physics and astronomy after a brief stint at Harvard she lived with her parents for 10 years during that time she contracted scarlet fever and lost most of her hearing to after 10 years someone got married she was able to come on as a Harvard computer to give you a comparison a student of her caliber or henria lit's caliber or Antonio mari's caliber today would be off to one of the greatest gr best grad programs in the world they would not be living with their parents for 10 years hoping that a position opened up this is her at her graduation from Welsley looking through a very very small refractor and what she did was organize reorganize what Willamina Fleming did accounting for what Mari had noticed in the Spectra Mari had noticed that certain stars like oars had extremely strong helium lines which other stars like M stars with very faint hydr hydrogen lines did not and so Annie Jump Cannon did a little bit of reorganization and some editing she moved the oars to the top of the sequence because if you're producing helium lines then you're hot she moved the B Stars next to the O and then edited the rest of the sequence down this is the sequence we still use to this day it's a little difficult to remember so we use OB a fine guy kiss me or a Oba fine girl kiss me depending on your preference and so now this x-axis in addition to being color from red to blue is now the spectral sequence of o b a FG km and by the way if you ever see this on a license plate astronomer in addition anti Jump Cannon was the first of the Harvard computers to actually be allowed to shockingly observe these telescopes are extremely big this is her in Peru at The Outpost in Peru they hadn't discovered Chile yet I don't think and maneuvering the bottom of the giant refractor there these telescopes are extremely long extremely heavy and nothing's motorized today you sit in a control room you tell the the um you tell your telescope operator I want to go point at that and then the telescope operator punches some stuff into your computer and the telescope magically moves there's no magic at this point you had to physically move the telescope and this demand and this work was deemed to be too physically demanding for the poor weak defenseless women I'm I don't know where they got that idea so she also did she was the first of them but not the last to actually do make observations and she became the world expert in this and in 19 in the summer of 1912 she went to Europe and attended conferences and spoke and at a in a in a meeting that was the precursor to the modern international astronomical Union she said was very surprised to find that she was put in the committee of the classification of Stellar Spectra now I'm thinking she's being a little sarcastic here um and she talks about sitting at a long table and being the only woman in the room and since I have done almost all the world's work in this one branch she was the classification of staler Spectra at this point it was necessary for me to do most of the talking I wish I could tell you that this has changed it's better it is better I am usually not the only woman in the room there's usually two others maybe um but I have definitely been in meetings where this was the case in 1919 about seven years after that um Edward Pickering died his replacement at the Harvard Observatory was a man named harlo shapley who is better known in astronomy history circles as being completely wrong about the scale of the mway Galaxy in fact he was um the one that made the the measurements of the distance to the LMC using Henri leaveit seid using HRI leit seid relation like Edward Pickering before him he supported the Harvard computers Annie jumpan and Antonio Mari were authors on their Publications so was Henrietta lit in fact if you cite the period SE the sephi period Luminosity relation you site leave it however he also did refer to the work they did in terms of girl hours so you win some Lua the final player in this I guess you would say drama is a woman named Cecilia Payne is a woman named Cecilia pain and you will have to bear with me I'm about to give you a very fast introduction to Quantum chemistry she got she was from England and she read physics and astronomy at Cambridge but she doesn't have a degree from there because in 1923 Cambridge did not Grant degrees to women when she asked about what the opportunities were for doing astronomy in England she was told you can be an amateur while teaching shapley had come he was now the director of the Harvard Observatory had come to Cambridge and given a talk so she knew about the Harvard computers she cobbled and as all scientists do to this day she cobbled together fun and moved over the Atlantic Ocean having done an international move with Skype I cannot even imagine it when she arrived at at Harvard in Cambridge Massachusetts because you know why mess with a name she followed instruction she had followed advice that she had been given to set out to make quantitative the quality qualitative information that was inherent in the Henry Draper system so up until this point they've said the hydrogen lines are stronger in these stars and they tend to be Bluer Than these other stars but there was no numbers associated with it you couldn't say that an oar had this temperature because the ability to do that depended on knowledge of a of a science that at this point was only just getting started called quantum mechanics you had to understand the structure of an atom and how electrons moved in that atom and Cecilia Payne was perfectly positioned to do this she had been in Europe so she knew about Neil the the bore model of the atom I did warn you we were going to do quantum chemistry this is a very cartoonish model of an atom you have the nucleus here with the protons and neutrons and different levels for the electrons repres resented here by this lovely blue circle as electrons move up and down so if an electron moves down a level it emits a photon it emits light and it emits light at a very specific wavelength this is actually how you get the lines in a Spectra and there are a series of and with that very basic model and if that and if for that electron to jump up to a higher LEL level it needs to absorb light and it needs to absorb light at a very very specific wavelength so the transitions you saw the lines of the hydrogen Spectrum are the movements of electrons up and down the levels of the hydrogen atom and with that knowledge Saha here developed a set of equations using quantum mechanics that could tell you if you know the atom that you're looking at which you know from the Fingerprints of the Spectra you can determine what the temperature of the gas is is everybody with me yes okay just checking I don't normally try to throw quantum chemistry and quantum mechanics at a public talk now she did this so she shows comes to Harvard and they happen to have the largest Repository of Spectra in the world on these glass plates so she can look so she sets about measuring the details of the Spectra and applying saha's equations to determine what the quantitative temperatures of these stars are this and just this next slide is not to scare you but to give you a sense of what she did she did this 20 years before the first computer would be built and these are the Saha equations yes she did all of this by hand looking at multiple elements in multiple plates across multiple Spectra and that added the temperature axis of this plot that tells us that an oar is 30,000 de Kelvin I would say that I would put that into more normal units but I think when you're up at 30,000 I don't think the the temperature scale stops mattering you know that our sun is about five or 6,000 Kelvin and so now we can say the temperature increase not only just the temperature increases but exactly what the temperatures of those stars are this is why o Stars had no hydrogen lines they're so hot that the hydrogen is completely stripped of its electrons and as you start to cool down just a little bit you start seeing hydrogen lines again now this alone would have put her into the history books but she wasn't done I'd like to remind you she's still the grad student at this point um for those of you that are having flashbacks to chemistry I promise I'll get rid of the periodic table in a minute she could also use those same equations to determine what the universe was made out of now think for a minute you're living a hundred years ago you look up and you assume that that is like this you're going to see a lot of iron a lot of carbon a lot of oxygen there will be hydrogen and there may be a little bit of helium but you're not expecting the periodic table quote unquote of the universe to look that much different than what you see here on Earth and so Cecilia pay looked through the the Harvard plates she did the calculations Again by hand and she found that it looks a little different for everyone that ever hated chemistry you should have been an astronomer we have hydrogen we have helium and everything else is a metal but more importantly hydrogen makes up 75% of the universe about 25% of the universe is helium everything else is a trace element formed in the core of a star in 1925 this was outrageous this was insane this went against all of the prevailing wisdom and you're a grad student you're junior and you're a woman you're the first woman to ever study for a PhD at Harvard and one of the first in the world to ever study for a PhD and your and shapely decides you know what we need to check with someone more senior who knows about this stuff this is Henry Norris Russell he is the r of the HR diagram and they sent him him Cecilia Pain's thesis and he wrote back to her that it is clearly impossible that hydrogen should be a million times more abundant than Metals note he hates chemistry and he convinced her to temper her conclusions in the paper to say this is probably wrong it's a measurement error several years later he published the exact same result and barely cited her the good news is most of the men in this talk are generally awesome for their time this guy is a complete I'm not going to say it publicly however Cecilia Payne's thesis um Stellar atmospheres a contribution to the observational study of high temperatures and reversing layers of stars has been called the most brilliant PhD thesis ever written in astronomy it is incred it would be incredibly impressive work today let alone 100 years ago and at this point the story of the Harvard computers as an active group somewhat ends this is a transition Point transitioning from the women being Harvard computers to the women being scientists and considered scientists in and of their own right the people that I talked about in this talk are only four are only five of dozens of women that worked at the Harvard Observatory from 1880 to to the 1920s I'm not even sure a complete list even exists by the time the Harvard AR the archive was complete there were half a million glass plates in the collection each plate containing countless Spectra and they classified and characterized the Stars on all of these plates Annie Jump Canon who took over for will Willamina Fleming after her death someone came in and said I want SW and I figure that's in the constellation of Andromeda but she rattled off the five-digit plate number and sure enough the requested star was on that plate the work this is a picture Cecilia pain is in the middle and Annie Jump Cannon is behind her this work their work is the backbone of Stellar modern Stellar astrophysics without these women we don't have modern Stellar astrophysics Willamina Fleming died in 1911 she was the first of them she was also one of the oldest remember most of many of her contributions were cataloging and making sure that the plates were organized and so that someone could actually find what they were looking for and even in astronomy her contributions have been largely forgotten I actually didn't know her name until I started researching this talk on her tombstone under her name and the dates of her birth and death she simply had written astronomer and remember she is the only person that I've highlighted here that did not have a degree in astronomy Annie Jump Cannon died in 1941 this is a picture of her looking at one of the glass plates they would Mark in pencil next to each of the Stars preliminary classifications possible variables that could then be wiped away afterwards during her lifetime she would classify hundreds of thousands of stars she could look at one of those Spectra on the glass plates and say oh that that's a B2 as casually as you decide whether as you look at anything that's a B2 that's a g that's a m the OB afg km spectral classification sequence that she developed was adopted by the international astronomical Union in 1922 and it is still in use today and if anyone could come up with a better pneumonic to remember it I am all yours she received a prize from she received a prize for her work from a group that supported women in research and an Academia of $1,000 dollar and using this money she endowed a prize in her name the Annie Jump Cannon prize for decades this was given only once in a while to a deserving woman it is now given annually to an exemplary early career woman at a United States institution which I take to mean that there's now more of us than there used to be Antonio Mari would work intermittently at the Harvard Observatory for decades one of the reasons this was intermittent is that she couldn't make enough money as computer to actually live so she was often doing teaching jobs in addition to her work at the observatory and would burn out would leave for a while and would come back in 1944 she became the second recipient of the Annie Jump Cannon prize and passed away in 1952 that complex spectr classification sequence the fact that the spectral lines of different of the diff of some of the different Stars looked different even though their strengths were the same is now how we DET has now how we differentiate between types of stars so how many people have seen Beetle Juice the bloody shoulder of Orion it's really bright right how many of you have heard of proximus and Tori yeah it's it's nearest star to the sun beetle you but you can't see it from Earth with a naked eye it is so dim that even at 4.1 light years it is too faint by for comparison alus and Tori is one of the brightest stars in the southern Sky Proxima centor and Beetle Jews are the same spectral class the difference is in the shape of their lines Beetle Juice is a giant star has a much broader line proximus centuri has a much nrow line and mari's classification scheme is how we differentiate between those types of stars in 1934 Cecilia Payne gulkin received the first Annie Jump Cannon prize the only recipient to receive it directly from Annie Jump Cannon her prize was $50 and a small handcrafted Medallion of a spiral galaxy she is also the other than willing Mina Fleming and her short-lived early marriage she is the only person who I've highlighted here that was married she went on to become the first female faculty member of the Harvard astronomy Department this took until 19 the 1950s and she became its first female department chair and then there is Henrietta L it she died of cancer in 1921 five years later a man you might have heard of Edwin Hubble used the found sepid in Andromeda and he used that period Luminosity relation that standard candle that Henri had a lit gave astronomy to determine the distance to the Andromeda nebula what was then known as the Andromeda nebula at that point there was a massive debate in the field about whether or not objects like Andromeda were internal to our own Milky Way or galaxies external to our Milky Way something that we just know now as a fact of the fields was under debate the distance that he derived from the Andromeda seids proved beyond a shadow of a doubt that Andromeda wasn't a nebula it was it was an external Galaxy that we now know to be 2.5 million light years from our own today the seids form part of what astronomers refer to as the distance ladder starting down here with Parallax so if you want an example of Parallax stick one finger out cover one eye cover the other eye quickly and then move your finger in and do it again your finger moves does your finger move when does it move more closer Parallax does the same thing does the same for stars but it only works for stars even today for stars relatively close to the Earth we can't even go outside of our immediate neighborhood around the Sun let alone outside of the Galaxy up here we have Cosmic distant scales measuring things that are millions or billions of light years away and we still need to know their dist es and in between are the seids we use parallax for those nearby seids for which we know Parallax we have their parallaxes we can get their distance with Parallax and that calibrates Henrietta lit's relation the seids in turn calibrate the even more distant distance scales when you hear about the the acceleration of the universe for which a Nobel Prize was awarded dependent on the period Luminosity relation whenever you hear an astronomer tell you how far away something is at the edge of the universe or even only five billion light years away it is dependent on this step in the distance ladder on the Centennial of her discovery of the period luminos it relation a symposium was held at Harvard this is something we do in astronomy we have symposia and at that symposia it was recommended that from there on out the sephi period Luminosity relation which is how I learned it and how most astronomers learned it be referred to as the leaveit law the next year the American Astronomical Society agreed and while you were asking me questions I have a little present for you from the 2 from the women from the 2017 women of astronomy thank you [Applause] questions yes so prior to the determination of the standard candle seod vles was there a Luminosity standard prior to that no not you had a chart on earlier that showed Luminosity or as you called it absolute brightness was that somehow different that was she could do it because she knew the initial group that it was done for were all at the same distance they were all in the LMC she didn't know the distance at the LMC but she knew that if one was brighter than the other it was actually that much brighter than the other so if you take so you have this variable of distance and if something is much closer to you if you have two things that are the same brightness and one is closer to you than the other the closer one will appear brighter but if those two objects are taken to about the same distance they will appear they will appear to have the same brightness and they will in fact have the same brightness if you have one object that's much brighter and is further away and one object which is fainter and closer they may appear to be the same brightness but in actuality the more distant one is brighter if you were to take those same two objects and move them to the same distance the one that is brighter will appear to be brighter than the fainter object and that was what allowed her to have to build the period Luminosity relation is that she didn't know how far away they actually were but she knew they were all at the same distance because they were all in the large meulin a cloud does that make sense other questions here yeah I was wondering uh did the um was was their work instrumental on connecting with Einstein that the that it was nuclear fuel Fusion in the core of stars you have hydrogen going to helium which her are you referring to that's yeah um it's the question of was her work instrumental with determining that hydrogen was in the core of stars and the answer is no Cecilia Payne's work dealt with the atmospheres of stars the very upper level that we the Photosphere that we can actually observe the physics of what actually happened inside the core of stars was done by other people when Evan Noble was looking for the SE variable in androma to find out whether was 25 million light years away or just part of our galaxy when you start looking at all these stars with the telescopes they had how do you know precisely which star you're looking at when you got to do it that those ladies were doing hundreds of thousands of stars you look in the outskirts is it telescope quality the question is how do you go about looking for sepian and Andromeda on photographic plates and the photographic plates were actually relatively high resolution you could see a lot of individual Stars on on those plates especially in a galaxy as as close to us as Andromeda is you would then take an extremely powerful magnifying glass and what looked like a cloud of stars would actually resolve out into individual points of light you also would not point the telescope at the very center of Andromeda you would look sort of slightly out from the center where the Stellar the Stars weren't quite as dense and it is still a technique that astronomers use to this day I'll back there in your beautiful image there are a lot of blue stars for a very old cluster you explained that the HR diagram is an evolutionary diagram can you explain the blue stars the blue stars are what are called horizontal Branch Stars so some Stars evolve off the at diagram they evolve into the giant phase and then they go through sort of an oscillation where they go from the red part of the diagram over towards the blue and then back and they're not when they move back towards the blue they're not burning hydrogen they're actually burning helium and then eventually carbon and oxygen for the most massive stars and every time they have to burn heav another element so when they they evolve up to the red giant they get hot enough to burn helium they move over and then when they run out of helium they they go back and they just move back and forth until they run out of fuel to burn at which point they for those Stars they're going to explode in a supernova I would also note in the image that we gave out today the blue here actually represents ultraviolet light uh this this image was taken with ultraviolet visible and infrared of detectors on wi Widefield camera 3 so the colors are stretched beyond the visible light in this in this image okay visually looks yellowish when you actually on back back you get that all right just as a curiosity Omega s can be seen from Baltimore no it show up in one of my H's comic pictures it's about 3 deges above the variet yeah veryy in Baltimore yes because you're you're way down against the Horizon aren't you there so that's tough in astronomy you do not observe a mega from the southern from the northern hemisphere the telescope operator would kick you out of the room yes if you could name a Space Telescope after one of these women who would it be and why so the question is if you could name a Space Telescope after one of these women which ones Canon Space Telescope we have kashin Space Telescope it would be one of those three um I think it would depend on what the mission of that telescope was if it was a telescope to push the distance ladder then you name it for hen or leave it if it's a telescope whose primary mission is going to be to go after stars and you jump Cannon um if you're probing fundamental physics pain so I think it would depend but I think it's high time we named telescope after one of these Maples I can second that uh other questions we have review for me please the uh absorption lines uh each is it each element has has its own absorption pattern or is it are we referring to something else when we're talking absorption patter each element has its own absorption pattern um we usually talk about them the way that you think about fingerprints the specific the specific sort of swirls within your finger may be repeated in another person but the combination of those patterns on all 10 of your fingers is unique to you and the same thing's true of the different elements um the there may be a line very close to hydrogen Alpha in four and another element but the pattern of hydrogen Alpha hydrogen beta and hydrogen gamma and hydrogen Delta is unique to hydrogen and you you look for those patterns rather than the individual ones all right any last questions all right I see that arini is here um so everyone say hi to arini she is our telescope operator for the Maryland space Grant Observatory and if you would like to go look through the telescope she will take you are you going to come down here so that that that CU people are going to be leaving from over there so if you would like to go across the street and meet with aren and she'll take you across the street uh next month is to be announced but I will have a speaker for you on June 6th and let us give a very warm thank you to Mia boo [Applause] well the the point was that you know the point was this was hard this is the pain of the ass this is the pain of the I've shown the I've shown the christofel symbols yes com