 Thank you so much for sharing your time with us today for this NCAR Explorers Series lecture when you need darkness to see the light. Total solar eclipses with Dr. Paul Bryant. I am Dr. Evie McCumber and I am an educator here at the National Center for Atmospheric Research or NCAR. NCAR is a world-leading organization dedicated to understanding Earth system science, including our atmosphere, weather, climate, the sun, the sun. So I'm excited for this. And the importance of all of these systems to our society. I am really glad that y'all are joining us today to learn about how total solar eclipses have captured the heart of solar scientists. For this event you will be able to ask Paul questions following the lecture and Aliyah will help moderate so that we can ensure that we hear from both our in-person and our virtual audience. If you are here just raise your hand. Aliyah is gonna bring a mic. There is an Aliyah. I know you can't see her but she's somewhere. When you get the mic make sure that you point at your mouth so that the people online can hear you. Okay, if you're joining us virtually you can ask your questions using the Slido platform. For a virtual audience if you scroll down this webpage you can see the Slido window just below where you're seeing this live stream. And if you haven't already for our online audience go ahead and click on the green join events button and then you can ask questions on the Q&A tab. Paul also has some really interesting poll questions for us. So for both our in-person and virtual audience please respond on Slido. If you are in-person I know that we have been having some issues with getting into Slido so if we can please bring that QR code back so I can give you some time to get into Slido. Yay! So if you can go ahead and get the QR code going so you can log in. Please make sure that you're using your phone to navigate to this webpage. Yay! And make sure you are joining Slido because we want to hear your thoughts with regards to our word cloud which is going to be asking what do you think of when you hear the words Solar Eclipse because we are really going to get to that very soon. In case you want to re-watch this events later it's going to be recorded and will be available on the NCAR Explorer series website. With us today we have NCAR scientist Paul Bryant. Paul is a scientist at the High Altitude Observatory at NCAR where he researches the ways the Sun affects life on Earth. To do this he uses observations from many different telescopes both on the ground and in space which each give unique perspectives on how the Sun's atmosphere is evolving. Dr. Bryant has been involved with field expeditions to observe Solar Eclipses since 2017 including leading a team to a mountaintop in Chile. In addition to solar research Paul has also conducted research in the fields of supernova remnants molecular clouds in comets. Now before I turn it over to Paul let's check out your thoughts on our word cloud so if Jesse and Christopher could please share a slider for us and I give you Paul. Come on Paul. Thank you Evie for that kind introduction. You might have been listening to what she said and think why does someone who gets paid to study the Sun have the authority to come up here and talk about the one time where we don't even see the Sun. So I start to start off with a confession and that's that this talk is not really about total solar eclipses at all. It's about the Sun. So I feel like it's false advertising. Alia's not locked the doors yet so feel free to to leave if you came for some other reason but I will touch on eclipses and how eclipses help us understand the Sun. Can we move back to the slides? Okay so let's start with let's get away from eclipses and start with when we actually can see the Sun. If you look up at the Sun right now which you shouldn't do unless you're wearing protective glasses you'll see something like this right? This is what we call the photosphere of the Sun. This is the visible part that you would see with your eyes. There are some features on it but for the most part it's kind of plain and boring but the Sun's actually made up of many different layers. In the core of the Sun atoms are pushed together with gravity and hydrogen atoms fuse together to create helium but it also creates a lot of energy and that energy eventually is forced out from the center and eventually gets to the surface which is the photosphere that we just saw in the previous slide but it doesn't stop there right? It keeps going and moves out into the Sun's atmosphere that we call the corona. So we can move now to a couple of the slido questions. These were kind of designed just to kind of gauge your what the people's background knowledge is on the Sun and one question was on whether you think the corona is hotter than the surface of the Sun or cooler and then I forget what the other one was something to do. Oh yeah here we go. So most people think that the corona is warmer than the surface of the Sun and a lot warmer. Most people are correct but I want you to take a minute to stop and think about does that really make sense right? If I let's make an analogy with a campfire right? If I'm out camping and I'm making s'mores do I want my marshmallow close to the surface of that fire to melt or do I want to move it away? If I move my marshmallow away nothing's going to happen right? But it seems to be the opposite thing is happening on the Sun like the surface is much cooler than the atmosphere and when I say cooler the surface is still 6,000 degrees right? It's hot but the corona is a million degrees. So why would that be? And that's something that we solar physicists still don't really understand right? We're trying to part of what I'm trying to get across in this talk is our observations will are trying to go towards answering that question. So then the next little question was to do with how the Sun can affect life on Earth and I think there are affect power grids is the correct answer here but why internet services I would say is also correct right? You kind of need power for your for your internet. As far as we know it cannot create tsunamis and the planet is still here so it has not destroyed the planet yet. But all of these effects are driven not real not by the surface of the Sun but by the Sun's atmosphere the corona and that part we can only see during the eclipses. So let's go back to the other slides now. Okay so I spoke about when the material reaches the surface of the Sun it doesn't stop there it comes out and it forms an atmosphere that we call the corona. That corona is not some steady environment right? This is a you can see the surface of the Sun on the left here and the material is flowing away and that we call this the solar wind that eventually reaches the Earth. It can interact with the Earth and cause the things that we spoke about on that slide or comments such as destroying the planet. This kind of looks like it's a nice smooth flow and it's kind of easy to understand but it's not always the case. Sometimes you can get large eruptions happening and these are the type of things if it is directed towards the Earth really cause problems on Earth. And so I kind of would like to go back to the campfire analogy a little bit now. If would you see this sort of thing on a campfire? No everything is kind of like on the surface of the fire yeah you might see like kind of little undulations right? But when you move out into the atmosphere of the fire nothing really happens it's just kind of warmer and getting cooler as you move away but there's all this structure that you see in the Sun and the difference between a campfire and the Sun is that the Sun is magnetic and I'm not going to go into any details on the Sun's magnetism here. If you're a kind of regular at these Explorer events Rebecca Centeno gave a really nice talk on this subject a few years ago so and if you haven't seen that it's on the NCAR's website you can watch the recording I encourage you to do it it's much more interesting talk than the one I'm giving now. But part of our research is can we not just measure the corona but measure the magnetic field and if I take a fridge magnet and I kind of throw it into the campfire nothing happens right I'll get hot I'll melt but it's but nothing's really going to happen because the campfire is not magnetic if I take that same fridge magnet and throw it out of the Sun it's going to melt a lot faster for one but it'll also be deflected right the magnetic field will move it in all different ways but if you think about that fridge magnet if you take it up to your fridge let's take a more sensible example and you can feel it being attracted to the fridge but you can't see the magnetic field that is causing that attraction right so we need to kind of get creative in the ways to image the magnetic field and I'll kind of get to that a little bit later. Okay so what happens when this solar wind flows away from the Sun and gets towards the Earth and I think there is this this understanding of the Sun is our star but it's some distant object right I'd prefer actually to think of the Sun not as a distant object but as something that we live inside of if you think of the corona and its extension we're inside the solar wind right now thankfully the Earth has a magnetic field of its own that deflects most of this particles when they're coming in they don't really impact us too much but sometimes they do and that's what's shown in this figure on the you can see here the the kind of circular shapes are outlining what the magnetic field looks like so on the right you see the magnetic field of the Earth that deflects most of the particles coming from the Sun but the particles from the Sun have magnetic field of their own and if they're oriented in the right direction like you see here they can kind of sneak in a little bit they can break through the Earth's magnetic field and cause sometimes things that are nice like the aurora but also they can cause some problems like GPS satellites can be disrupted by them radio communications can be disrupted the power grid can be impacted etc okay so let's talk about how do we measure or how do we predict space weather and I think it's useful to kind of make an analogy with Earth weather and if you if this if you sent a satellite up into space and you observe the Earth like this do you think you could predict what the weather would be like tomorrow yes well okay so what would the weather be like tomorrow my answer is no because what this is shown is the surface of the Earth right I can't tell what the weather is like without looking at the atmosphere of the Earth so I really need something like this that shows the Earth's atmosphere and it's the same with the Sun right I can't predict the Sun's weather just by looking at the surface of the Sun that's what we see here but the problem is that the Sun is different from the Earth because the Sun's surface is a million times brighter than the Sun's atmosphere that's not true for the Earth we can see the clouds right now just by looking up in the sky but if I look at the Sun the brightness of the surface of the Sun drowns out everything else and I can't see its atmosphere unless I have an eclipse and that blocks out all that brightness and suddenly I can see the Sun's atmosphere so what you're seeing here is the corona and actually how we discovered the Sun had a corona at all was through solar eclipses this was the first this was the first way anyone could ever see them they didn't actually know was the corona to begin with there was a lot of theories going right what are they seeing one of the early theories hundreds of years ago was that we are seeing the moon's atmosphere this is the sunlight passing through the atmosphere of the moon getting to us and but we now know that the moon doesn't have an atmosphere or not much of one certainly nothing that can create this and so so we eventually realized that this was the atmosphere of the Sun that we were that we were seeing and so before I start this actually let's go back and go to the slido questions on on what people's thoughts are on on eclipses because I'm going to transition now into the part of the talk that you actually came here for and talk about eclipses and how they happen and all right so how often do solar eclipses occur this is a little bit of a loaded question right because what is a solar eclipse there are different types of solar eclipse I'll get into that in a minute so yes every the majority of people are right to say that solar eclipses happen every year they're not all the same some are annual or some are partial some are total and a total solar eclipse happens on average about once every 18 months but the reason I put every month is because that might be something that seems intuitively correct right the moon orbits the earth once a month right so surely it just gets in front of the Sun once a month and we'll get an eclipse every month and that's not true and I'll have so I'll show you why in a second I think there's another question here am I right okay how far into the future was total solar eclipses end I think most people think in many many millions of years but there's quite a lot of people think they will never end and the answer is well actually I'll leave you I'll wait like let's go back to the slides and you'll find out the answer okay so let's talk about why eclipses happen the simple answer is that the moon gets between the earth and the Sun but think about this for a second if you look up into the sky the moon and the Sun look roughly the same size that feels like something we take for granted but it's actually it's just a coincidence right the Sun is 400 times further away than the moon is but it's also 400 times bigger than the moon so they just so from our vantage point they look the same size in the sky and that's really awesome because it means when the moon gets in front of the Sun it covers it just perfectly and this image here this is not to scale right the Sun's actually much further away so this makes it look like half of the globe should be eclipsed when you do get an eclipse right eventually this movie is going to zoom out this is a 28 to one scale to actual one to one scale and you can see that that shadow of the moon is really small right so that's why when you get an eclipse on earth it only passes over a really small localized area and on the earth and you need to travel to to get to it and okay so get to this question about why does it why does it not happen every month the moon orbits the earth every month and but the moon's orbit is not on the same plane as the earth's orbit around the Sun right it's inclined a little bit and you can see that here so sometimes when it's between the moon and the earth it's actually up above and sometimes it's down below so that that's why it doesn't happen every month but then there's another complication as well and that is that the moon does not orbit the earth in a perfect circle it's a it's almost a circle but it's actually an ellipse and when it's closest to the earth it looks a little bit bigger in the sky to us than when it's a apogee when it's farther from the earth so if an eclipse happens when the moon is closer to apogee that means that the moon is actually smaller than the Sun in the sky and it that's when you get a so-called annual eclipse right the moon covers the Sun but not entirely and you have this ring of fire around when it's near perigee the moon is as big or a little bit bigger than the Sun and it covers the entire thing so when you add all of these things together you get a total solar eclipse not once a month but on average once every 18 months and it varies it's gonna the inclination of the moon the exactly where it is in the orbit kind of all goes together to figure out when and where this will happen and okay so let's get to our question on well eclipses ever end I think and yes clearly they'll end because you think what one reason you thought they might end in many millions of years is because you think the Sun might explode right and that's true with that that'll be many billions of years actually it's 600 million years and how we know this is that the Apollo astronauts took up reflectors to the moon this is Buzz Aldrin here installing the first one so they left them on the moon and then now we can fire laser beams at those reflectors they reflect back and we measure how long it takes the light to get there and come back and by measuring that time we know very precisely how far away the moon is it turns out the moon is moving away from the earth about one and a half inches per year so slow right but one and a half inches per year times 600 million years means the moon will eventually be too small to cover the Sun and you'll never get a total solar eclipse again so take your chance now you've only got 600 million years before you they will never happen okay so if total solar eclipses are so awesome for science and for being able to predict space weather and there is also a problem with them three problems really one they only happen every 18 months right if I want to predict the weather every day I don't want observations once every 18 months right the weather channel would go out of business the other thing is they only last a few minutes right so I can't get a continuous observation and then the third thing is that they're not everywhere on earth they're very localized and you have to travel oftentimes to remote places to see them so why did science scientists kind of thought why don't we just make fake eclipses that happen all the time and that was our final slido question asked about and it is why did scientists actually make this happen so there is a whole range of answers here and I think two of these answers are actually correct one correct answer is the 1930s when they first made a telescope that kind of could simulate an eclipse but I think don't be silly they can't do that is also correct because I'll get to the fact that these instruments are not really an eclipse like there's nothing really can emulate an eclipse so if we go back to the other slides now people are changing their minds okay so you so so you would think in principle I'm gonna build a telescope and point it at the Sun why don't I just make a fake moon right oh I'll make a little disk and I'll put it in front of a telescope it will be the exact same size as the Sun I'll block out all the sunlight I'll get an eclipse conceptually that sounds simple but in practice it's very hard to do and a reason or a way to understand why it's so hard is let's say you go outside just now and you put your thumb up to the Sun you could block out the Sun right you wouldn't see you would be able to look up there and not be blinded but would that be the same as an eclipse do you think you would be getting the same experience no yeah exactly and and the reason for that is that the sunlight is still coming into the Earth's atmosphere it's scattering off all the Earth's atmosphere and still getting to your eyes so the same thing happens with a telescope right if I put a fake moon in front of the telescope all this other light still gets in there but if you're very clever this kind of move yeah we will if you're very clever about how you build this telescope you can get around this these scattered light effects right you put that fake moon inside your telescope not outside you have lots of ways to block out the scattered light that are kind of technical and not really very interesting but the first guy that actually made this happen was a guy called Bernard Leo that's him down in the this guy thing that's him there down here on the bottom right and he was a French guy and he made this happen in the 1930s people had tried before but kind of couldn't get their instrumentation to work and then there was a guy from around here from the Rockies Donald Menzel and he traveled to Europe he met Bernard Leo and he thought this is awesome why don't we make one in America so he came back here and he hired a guy called Walter or Roberts who you might have heard of because this building's named after him and he was the first director of NCAR he eventually started this whole organization anyway Menzel hired Walt Roberts and said build me one of these here so what he did was he went to climax which if you're from around here you might notice up this kind of near-leadville up to the west and he chose that site because it's high in the in the high altitude right the higher in the earth's atmosphere you get kind of there's less less of the earth's atmosphere is messing with your observation so he wanted to go up to as high an elevation as possible and this was already a Libdanum mine at that point so he kind of worked out a deal with the miners can I take a little bit of your land and build a telescope here this is him with his wife just kind of going to work in the morning I guess kind of snowy up there and it was a kind of a lot of work but he eventually got it to work and this is him this is actually one of his observations in the 1940s and he did a lot of other stuff when this in the 40s a lot of the driving behind having one of these in the US back then is because this was during the Second World War right and the Allies were communicating with radio communications back then if you remember earlier on I said that radio communications is one of the things that can be impacted by space weather so they wanted to know when to send their radio communications that would not be interrupted so if he saw something like this happening he would tell them this is not a good time your radio is going to be interfered with and that was that was a lot of the the practical use of excuse me of the of these observations back then in the 1970s that site in climax was decommissioned the kind of for a couple of reasons one was that they were still mining there right and made the air kind of dirty with a lot of other stuff that was not good for trying to do solar observations and I think and then they built a new observatory in Hawaii so I think the second reason was the weather is much better and this is their site the Mauna Loa Observatory that's still currently running when we don't have volcanic activity and this is an example of the observations we can take today so they're they're not quite as goodness in eclipse but they're pretty close and more importantly we can take them not 24 hours a day but about five hours a day you need obviously you can't take this in night time right and you need the Sun to be up but you if the Sun's too close to the horizon it also doesn't work very well you've got Earth's atmosphere to contend with but even though we had these observations using these so-called coronagraphs they still went on eclipse expeditions so this was the first one the N-car it wasn't called N-car back then but it's what became N-car and led to Sudan and one thing I want to point out is look at how huge these things are right I'm amazed that they took this stuff like all over the world for a four-minute observation they went to the Cook Islands in 1958 they kind of I mean they you don't really have a choice where to go right the eclipse happens where it happens but they kind of got lucky I think with some of these locations and in Bolivia here and I want to point this one out because if you see this telescope here that they have behind the curtain the little bit wizard of Oz right and that's the same telescope that you see out in the lobby here that's the new Kirk telescope and it was designed and it has a very interesting design and that there are special filters in it that kind of attenuate the light differently as you move away from the Sun so that you don't get dominated by the bright stuff that is close to the Sun you can you get a kind of even picture where you see the corona spread all the way out as far as your field of view is and they took this telescope to many different places for for decades this is that again in Mexico and more recently this is the last solar eclipse that was in the US we took much smaller stuff you can see this time we packed this up and put it in the back of the van and drove it there I can't imagine like taking this huge apparatus anywhere and then most recently we went to to Chile in 2019 so the question is if we have this instrumentation in Hawaii now and then and there are other of these coronagraph telescopes around the world that can fake an eclipse why do we still bother with eclipses at all my answer is I like to go to Chile in places like that right it's fun but the reason that I tell my boss is because if I compare my eclipse observation with a coronagraph observation they're not really comparable here's here this is observations from the same day right this is the eclipse that was taken in 1980 and India and here's what the monoloa instrument took in Hawaii that same day you can see that the quality isn't so much better here right and it's not just the quality if you also if you look and this dotted line that you see kind of inside the black square that's where the Sun is so this so-called fake moon that they put in front of the telescope they have to make it a little bit bigger in the Sun if they make it the exact same size there's too much sunlight scatters in so you can't really do this do the same thing the the difference with the moon is that it's so far away it's outside the Earth's atmosphere right it blocks all that light before it even gets to the Earth so you don't need worry about that scattered light you do need to worry about it if you're doing your fake eclipse in the so so you can't see really low down in the corona the same way as you can with a with an eclipse and then here's again it's another example from 2017 you can see that our observatory observations now are better than they were before but they're still not as good as the eclipse so we still like to go on eclipse expeditions but one drawback of the eclipse is that it only happens for and okay so this this is the 2020 for eclipse it will happen April next year it will last four minutes the maximum time an eclipse can happen is about nine minutes right so you only get a few minutes of observations and to try and predict space whether you want to see observations over a long period of time see how things are changing in the corona or things being ejected and so if we have one telescope in the path of the eclipse the shadow moves over is we see the corona for four minutes and then we're done but what if we're kind of clever and instead of having one telescope we have a lot of telescopes all along the eclipse path and the key to this is making sure that all of these telescopes are exactly the same right because if I want if I take 35 four minute images and stitch it all together I kind of want a seamless movie I don't want kind of the exposure changing the everything changing so that's what we are doing for next year we're deploying 35 of these eclipses all the way from Texas up to Maine and they will be spaced so closely together that there is never any gap right so they'll they'll be all along the eclipse path and then after the fact we'll stitch a movie together that each individual one is four minutes but total movie is an hour and then you can really see things changing in the corona over that time so here's all the locations where the telescopes will be and we do not have enough scientists to this is this is an example we did some tests in Australia this year and this is kind of an example of what you would see with this instrumentation we don't have enough scientists to man all these stations so we're engaging the community to do it right if you are going to be near the eclipse path and you want to be involved in this project let us know there's an email address there and and don't worry about grabbing it right now you can talk to me after if you're interested and but the cool thing is that we're trying to engage underserved communities and we are giving them all the equipment to keep after the fact so this stuff is not just nice for looking at eclipses it can be used for nighttime astronomy for for different things and the other problem with eclipses is that if you're viewing it from the earth I might have clouds right and I don't see anything you don't get to kind of keep observing or maybe the clouds will go away the eclipse happens when it happens that's nothing you can control so one idea is to get above those clouds in an aircraft this is an aircraft called a WB 57 this used to be a military bomber and the military decommissioned them and NASA thought let's buy a few of these out and reconfigured them so what they did was they added this nose turret thing that you see here and that you can put instrumentation and we have cameras in there and you can see that it can turn around right so the so the pilot will fly along the eclipse path above the clouds he'll orient that front nose cone to point in the right direction as he's flying it can move to track the Sun and you are kind of guaranteed to get good weather and so one way is to put your stuff on the front of the front of the point the other way is to what NCAR did is buy a super high-end luxury jet rip out all the cool stuff inside and just cram some instrumentation in there right so that's what they did here this is this is like the kind of if you've seen succession this is the kind of planes they fly around in right but they've got nice comfy couches and beds NCAR has all this crap so what what they do is they have all the instrumentation that they need to observe the eclipse and then have a really precise pointing system with mirrors that makes sure they look through a little hole that they drilled in the kind of fuselage at the top the points towards the Sun this is a little bit different from that nose cone situation and that nose cone could move right the aircraft can't like you can't change where the where the window is right so you have to get a little bit creative and how you fly the pilot might have to kind of tilt it a little bit and but these are some of the things that we were we're doing for the eclipse in 2024 we're flying the NCAR aircraft to take observations and this is one of the observations from the 2017 eclipse this aircraft flew and this is someone that was on board put their iPhone out the window to see what you can see right and you can see that there are the clouds here would have been a problem for them right they're above the clouds but it's it's really interesting to see like the shadow come across and how how different it looks when the eclipse comes so let's get to the eclipse then the upcoming eclipses and let's start with how many people here have seen an eclipse okay how many people here have seen a total solar eclipse I would say like about half of the people in the audience and and so I want to talk a little bit about what to expect when you see one and I want to try and encourage people that have not seen one to make an effort to see a total solar eclipse I think most people here that have seen a total solar eclipse will try really hard to see the next one right and that's kind of the best advert for it in my mind it's like it's it's not just one of those things where I've seen it it's like that was cool I'm going to try again and again and again so the next one that's coming up is in October this year but it's an annual solar eclipse right it won't be the same as a total solar eclipse there's still you still see some of that bright photosphere the next one you really want to care about is in April next year is the total solar eclipse and that's the one you can see the path of here yeah starts over Mexico goes all the way across the U.S. and makes it to Canada this is that this is an image I stole from from NASA and for some reason Mexico and Canada are completely under clouds but but the U.S. is clear I don't know if that's gonna NASA's bro so anyway choose where you think is going to have the best viewing conditions and go there okay so what can we expect to see at the 2024 eclipse sometimes there are planets in the field of view of the Sun obviously in the normal daytime sky you don't see the planets the Sun is too bright it drowns them out but but during an eclipse you can see in this case we saw Mercury in Jupiter something really cool about the 2024 eclipse next year is that there's always there's also going to be a comet in the field of view now this is an artist's impression it won't look like this right I am the artist in this case and I think I did a pretty good job but it's probably going to be a little bit smaller than that and but this lets me kind of transition to something else I'll it's kind of in the same theme as what we're talking about is the eclipse is cool but what is really cool about it to me is what it teaches me about the Sun that's the same for comics right comics is a cool thing but what's more interesting is what it can teach me about the Sun itself I don't really care about the comet so much the fact that we see a comet in the field of view near the eclipse it's actually not that uncommon there are thousands of common light they're often passing pretty close to the Sun and this is just an animation of over the years how many comments have come in close contact with the Sun most of the time though these comets are really small and they they burn up we don't see like if they get close enough to the Sun they burn up and they fizzle out you don't see them a few years ago we kind of got lucky and one of these comets was big enough and close enough to the Sun to be able to see with the coronagraph right with the fake Sun image and this is what it looked like this is this is a coronagraph image from space you can see the Sun's in the middle and you can see like the occulting disk the fake moon is bigger than the Sun's you don't see all the way down to where the Sun is but look at this one this comet came in usually it would burn up but it survived and it came back out right so when we went to some different instrumentation that looks close up in the Sun it looks in a different wavelength of light looks in ultraviolet and we looked at it really close again right if the comet's not here what does this image of the corona he out here look like it looks boring it looks like there's nothing there right when the comet comes through it releases all this material all the material gets gets sublimated off because of the sunlight and that material gets dumped into the atmosphere and then starts moving around in all these weird shapes that you might not predict this is this is on the other side of the Sun right the Sun here this is it's been around the backside and come out again and it's doing the same thing and if I kind of process this image and show it in a different way so that we kind of just instead of I keep the light from the comet as it moves through you can see all of the like the it kind of maps out and this goes back to when I spoke about can we measure the magnetic field on the Sun that's what's that's what we're really seeing here our original image doesn't show anything about the magnetic field but when the comet goes through it releases this material that material is influenced by the magnetic field and instead of flowing along the same orbit that the comet was going it gets it's like your fridge magnet it says oh there's a fridge over there it goes that direction right and it goes in all different directions so it shows you in some places the magnetic field is pointing this way some it's pointing that way and that helps us know what the corona is like magnetically and eventually how that magnetism impacts life on earth and so this is this is kind of like a map of here is a model of what we think the magnetic field might look like around the Sun here's what the comet did and we can test if our model is correct or not okay so something else you might see in the eclipse is Bailey's beads I think most people are probably heard of this and so why do you see that it was called Bailey's beads right and that's when there's another image after this one that shows you when the moon goes in front of the Sun it doesn't just cover it smoothly you get little pinpoints of light and the reason for that is that the moon is not a perfect sphere right there's all these craters on it and we've measured this there's this is images from the lunar reconnaissance orbiter that measures very precisely the landscape of the moon and then in blue around the moon you see like an exaggerated version of where it's where the moon has valleys and peaks and you see that during the eclipse so let's see what happens as the moon you as the moon kind of gets closer and closer to cover you see these little dots right and that's the Sun light coming through the little valleys on the moon another kind of cool thing you see is in red here that's what we call prominence material that's kind of material that is between the surface of the Sun and the corona it's like a transition region between the two and that's where a lot of that explosive events kind of come from okay so I'm kind of coming towards the end this is a kind of like I said I wanted to convince people that have not seen a total solar eclipse to go and see one and I I'm a super cynical person right before before the first eclipse I saw was 2017 I went to talks like this and people were saying oh you have to go and see the total solar eclipse if you haven't seen one you haven't lived right and I'm like sure I think it'll be cool but it's not really worth traveling for but after I saw one I was kind of a convert right it's like you can show people images of the eclipse what it looks like and but it doesn't convey what it's like I kind of compare I like to compare it to the Grand Canyon you can see a picture of the Grand Canyon right or you can go to the Grand Canyon and you're like oh my god this is amazing it's the same for an eclipse for me because it's not just it's not just the image right it's not just it's not just the sun not being there it gets dark it gets cold animals kind of go crazy they think it's nighttime should I go to bed but then four minutes later they're up again which actually happens quite often in my house but so I think the best way to convey how cool it is is to show you and a movie that the National Sword Observatory took of people observing the eclipse in 2017 here in the U.S. and I want you to concentrate on this little boy here watch his reaction when he gets dark thank you very much questions in house please raise your hand and Aliyah who was actually here see told you she existed will bring the mic to y'all so how about a satellite to do the same sort of thing as opposed to airplanes wouldn't that capture a lot of the solar weather yes and we do that right so that image I showed you of the comet that was from a satellite and it still has the same problem and that the occulting disk so the fake moon is still it's not as far away as the moon is right it's still in their instrument it's still close right so so there's still scattered light effects one really interesting idea that will fly next year is a is a is a new concept where instead of having a telescope with that occulting disk attached to the end of the telescope they're going to fly two spacecraft right now one spacecraft will be up the other one will fly some kilometers away so you get the distance and that's but it's very difficult like from a technology point of view to make sure those two spacecraft are lined up perfectly so it's it's it's an engineering like problem is very difficult but they think they can do it and that mission is going to launch next year hopefully I may have misunderstood quite possibly at the very beginning you were talking about the corona being hotter than the surface of Sun something to do with magnetism I didn't see why magnetism would make it hotter well that's why I directed you to Rebecca's talk which is that which is a whole different explorer right but I can summarize the the quick answer is we don't know the the better answer is that there are a lot of different things going on in the Sun that we think can what so to get the to get the atmosphere hot what you need to do is move that energy up into the into the atmosphere right and and so the question is how do you move that energy up and there are a lot of different mechanisms that could do it and the the Sun is not like a static nice steady body right there's lots of movement going on right so you get a lot of waves generated in the atmosphere it's a little bit like waves you see in the sea but they're in the atmosphere instead and they can push that energy up into the higher atmosphere so that's one theory of how that how that heats up yes but it's a little bit different because the atmosphere of the Sun is very tenuous right so friction doesn't really play a big role because there's not enough particles there to rub against each other more is further apart and so there are other processes that can maybe be responsible but we don't really know it's still a very active region of research I'm gonna take a question online sorry I'm going to bring up the question from Slido so what is the prognosis for weather across Texas for April of 2024 since you know that's a good question they so there are people that spent like is their career is predicting what the weather is going to be like for any given eclipse the most reliable way that they think to do this is just to look at that same day over the last 20 years and give you an average cloud cover for that day so the average cloud cover over the last 20 years tells me that the best place to be is as well the best place to be is Mexico right and if you need to stay in the US the best place to be is as far south in Texas as you can get but I will add this caveat so if you don't take the last 20 years if you just take last this year April 8 this year it's the exact opposite right Texas was terrible Ohio was awesome so who knows question so Dr. Walter Robert started high altitude observatory in Colorado he set his decommission Manaloa now is carrying on is the high altitude observatory in Hawaii or in Colorado both so the high altitude observatory was founded in 1940 right with at climax then the invented N car right which is more than just the high altitude observatory the high altitude observatory was to observe the Sun but when N car came along they wanted to do the Earth's atmosphere they wanted to do much more right so it's everything from the Sun all the way to the earth so what they did then was make HEO part of N car so HEO is the part of N car that still studies the Sun there are other divisions within N car that study climate on Earth they study tornadoes etc so the eight so HEO now is here in Boulder but also and we also have a we don't do any observing here because the observing conditions are not as great as up on top of a mountain in Hawaii so we also have our team in Hawaii so we're both yeah so Hawaii's where we do the observations Boulder is where most of the scientists work oh does the ISS experience eclipses any different from people on the ground um good question I think there so they're a little bit they're a little bit closer to this to the moon right if in the if the moon were between them and the Sun so so that that might vary like sometimes they might see a total eclipse when it might only see an annular for instance but I think that but that difference is is really small so I think it probably doesn't make a big difference what is really cool about the ISS is they can see the eclipse happening on the earth right so they can look down on the earth and see the shadow move across the earth and that's that's kind of that slide I had up before is actually is not a real image it's a simulation but it's the same thing that they see and astronauts have taken movies of that and showed they're not experienced the eclipse themselves they're kind of offset a little bit but they can see the moon's shadow moving across the earth oh yeah do you have a sense of what the volunteers will be doing who volunteer at this next solar eclipse and second question is when will the following one after 2024 be what when and where I'll answer your first question first and there are different types of volunteers right we've got 35 of those stations along the eclipse path what we're doing is having regional coordinators who are volunteers that are kind of in charge of eight or nine of them so there's four regional coordinators and they are kind of overseeing 88 of those individual sites but then at the individual site itself there will be people that will be operating the instrument so that means you need to go and point it in the right place set all the software up to take the data at the right time and there's a lot of training and advice that we provide in the training right to to help because we want the volunteers not already to be experts we're kind of trying to engage the public and have people that may be interested in astronomy get hands-on like experience of doing this so we're providing a lot of training for them to be able to operate the instrument not just for the eclipse but in the future tell them how to be able to take this telescope out and observe the night sky that's one of the troubles of going to see an eclipse if you're actually I think and it's better sometimes not to be bothering with your telescope right just go and enjoy it but yeah a lot of it depends how automated it is and these things are pretty well automated once you get it lined up in the right place you kind of press a button before the eclipse happens and it does it all for you so then you can kind of sit in your deck chair and enjoy yes are you gonna answer the second oh sorry the second question is the next eclipse and anywhere on earth is in 2026 and it will pass over Iceland then across the Atlantic and eventually Spain and the next eclipse in the US will not be till 2045 and it will come right across Colorado so maintain a healthy lifestyle you could 20 years with another okay will the volunteers be able to pick up the telescopes and move to a place where the weather is clear if necessary no and we deliberately don't want them to do that right because well we've got around that fact by placing these telescopes all along the eclipse path so that there's overlap right if if if one telescope doesn't take successful observations it might be because of clouds but it might just be because something else goes wrong with the with the instrumentation there the next observation over is close enough that it will also see the same thing right so there's uninterrupted coverage even if one goes down if two in a row go down then okay we're stuffed but the other answer to that is it's very difficult to predict what the cloud cover will be like in advance with enough time to move even if you think it's going to be cloudy lots of the times when you when the eclipse starts to happen because the temperature changes the cloud cover changes like things happen in the atmosphere differently and oftentimes it's cloudy and then suddenly the clouds move so we don't really want people yeah hello so I heard the relativity like the light bending was proven by the total us eclipse and I was curious that to me it didn't look like the light was bending there so I was wondering what was over that yeah that's that's an excellent another example of the eclipse teaching is about something else right which is kind of the theme I was going for here so that was Einstein's theory of general relativity what he said was if light travels past some massive body something with a lot of gravity like the Sun the light doesn't travel on a straight line anymore it bends because gravity bends light but that was Einstein's kind of theory that he had never actually been tested and the person who tested at first was Eddington and it was during a solar eclipse so how he did it was and there was a there was stars or one bright star and behind the Sun right it was kind of not not directly behind the Sun but just looking at offset from it and during daylight you wouldn't be able to see that star right the Sun was too bright you couldn't see the star during an eclipse you the sunlight got dim and you could see the star through the corona so they knew where that star should be like because you could observe that same star at night so they know where it should be then they measured it where it was during the eclipse and they saw it was actually offset a little bit and that means that the light coming from that star when it passed by the Sun bent a little bit so that it wasn't where you think it is we have an online question let's bring it up but in the meantime is will we be able to see the corona during October's annual eclipse no and I think so the October's annual eclipse still leaves a portion of the Sun right and I think the best way to understand why you wouldn't see the corona is the corona is a million times dimmer than the photosphere the surface of the Sun so if I if I block out 90% of the photosphere that's still 10% of a million it's still a lot right it's still way brighter than the corona so that's why you really need to get to total solar eclipse before you can see the corona if the sky is clear and weather conditions therefore be optimal for watching is every solar eclipse experience pretty much the same the way it looks or is it a different experience every time for whatever reason I think it's different because it's not to me it's not just about what's happening in the sky right it's happening is what's happening on Earth is is more interesting in some sense when a when Evie give the introduction she said that for the 2019 eclipse I went to a mountaintop in Chile to observe it and that one was really cool because from the mountaintop you can see the sea right Chile is really narrow right so I think you can see the sea from basically everywhere in Chile but when you're high up like that you could see the shadow of the moon coming across the sea towards us right so we knew the eclipse was coming before it got there and we were messing around with our telescope and getting everything right but you could kind of you could see it coming towards you and then it happened so that's specific to that location right and it's and that's the same for other locations have their own kind of specific cool things happening it's very different if it's high in the sky compared to on the horizon it's kind of it'll be like a different experience so yeah just to give you all a chance to think let me ask you my favorite question which is if there are any students that are online watching this what advice do you have do you give them if they want to have a career in what you're doing right now number one make sure you get a passport right because eclipses happen all over the place more importantly I would say do something you're interested in doing right if you think this is interesting I think that you that I think that's the best way to motivate yourself to learn to be able to become like what I do as a solar scientist so I studied physics at university but you don't need to study that to get involved in solar science and eclipse science there's many different aspects to it and engineering is a big one right when you look at these telescopes I didn't go any any detail of it but these are not simple things to build right and we have a team of like kind of well-trained engineers so if you're you don't need to be a scientist if you're an engineer you can get involved in instrumentation and computer science is a big thing a lot of when we look at the data from the Sun it needs to be interpreted and a lot of computer machine learning and artificial intelligence is kind of a big kind of buzz topic right now and you're kind of more used to seeing it in the terms of like chat GPT or something but it can be useful in interpreting solar images as well so there's lots of different avenues to get involved and you have mentioned that there are like 35 sites for next year where are you gonna be what are you gonna be doing I am still undecided but probably somewhere in South Texas where the weather has the best chance of being good so tell us a little bit more about the corona when you look at the solar eclipse you see like beams coming out outside of that beam is it still a million times warmer than the than the Sun surface or is it very or yeah it's kind of it's interesting right it's kind of it goes back to that campfire analogy where if it was just a fire everything would be the same as you go it would all be kind of very smooth but it's not the case with the corona you see different structures and yes it's still a million-ish degrees but the temperature varies right there's it's not there's not the corona doesn't have one single temperature it has a whole it's it's on average roughly about a million but it can go up to 10 million maybe in some like regions and so you see some temperature variation in the in the structures you see there but most of that structure is determined by the magnetic field right so all of the material in the corona is is ionized right so that means that it's so hot that the electrons have been stripped off of the atoms so it gets experience so it experiences the magnetic field so when the magnetic field is oriented in a certain direction the material kind of moves in that direction and that's a lot of the reason why you see some parts brighter than others because there's more density in some regions than in other places I'm going to ask you a question that's going to be like choosing your favorite child but out of all of the eclipse experiences you have had which one is your favorite I've only had two and I will choose the first one because it was unexpected to me not from a science point of view it was unexpected from a experience point of view I kind of like I said before I thought it would be cool but not that great and I think that was the one that kind of let me realize okay this is this is something really is it's a natural phenomenon but it feels unnatural right there's something kind of weirdly alien about it I have a very weird question so I if the sun is a gas what does it mean that there is a solar surface what works the surface yeah I mean it's not it's not a surface in the sense that you think of the earth having a solid surface right and the sun is his gas like is not quite a gas this is kind of gone into what we call a plasma where and so the difference between a solid and a liquid in a gas is like the molecules or atoms are far enough apart that it's ten years it's not dense anymore but the plasma goes beyond that where the atoms themselves start to come apart and the electrons come away from the nucleus of the atom so so it's a gas in the sense of its tenuous but it's also driven by the magnetic field so the surface of the Sun basically just means it's not a solid surface it's just where the light we see comes from right up anything below that all the light that's coming from below that gets doesn't escape the Sun it gets it kind of gets bounces around inside the Sun and never gets out and once it gets to that photosphere surface then it travels all the way to earth if there are no more questions let's just all take a second and thank Paul for this amazing lecture give a hand to Paul and honestly thank y'all for attending this lecture in total solar eclipses that is part of our Explorer series we have one coming up in September 13th and it's going to be all about field campaigns that start with an idea collecting all the data and I was promised pictures of penguins so there will be penguins in the top yeah so if you're interested in more and correct for a series of ends check out our website for upcoming lectures and conversations and if you want to relive this there will be a recording of all past events including Paul's you are going to receive an email so if you are 18 years or older please take a moment to fail our survey that helps us understand the impact of the program and how we can improve our next event the survey will close on Tuesday September 5th so you can have Labor Day off you can find that survey by scanning a QR code or you can ask either Lee or I if you would like to take the survey using our iPads I hope to see y'all next time and have a lovely rest of your night thank you for coming