I am a walker. Yeah, we have a slide changer or whatever Because I just realized I need to change right at this one point. I think so Everybody has their treatment up Man, it's gonna get to work. It's a gradient zone For you Until this is our first talk of the night I think over nine That's the Iraq Institute. It was an astronomy department syndrome foreign and Michelle completed his undergraduate studies in physics at the University of Sao Paulo and got a Ph.D. from the University of Pennsylvania and works on the development and application of new techniques for the discovery and characterization of the most distant bodies in our solar system, in our transmitting objects, and he's a member of the Dark Energy Survey. Alright, so we have a big brand new fog for tonight and not just got our first talk in exactly two years. Hi everyone, good night. Can you guys hear me fine? My voice is a bit well... louder? Okay, I don't know if you can hear the sound here, but my voice is not that loud. So I apologize, they'll try to push it here. Let me just figure out that I can work this thing. Okay, I can. Alright, okay, let me take the mic off so I can walk around because I do that all the time. Alright, so yeah, as it says here, my talk is going to be about how I, by mistake, discovered the largest comet ever comes. The key takeaway here is that I was not trying to find comets and I ended up finding one. So everything that I learned about comets was after I discovered this thing. So that's the last thing I hear. So I was looking at the trigger questions. I think I could only get half of them. So yeah, if you've got more than half of no more about comets than I do. Anyway. So this is my mental picture of the solar system growing up. This is what we have there. We have the sun and we have eight planets. At some point when I was a kid there was also Pluto, but it doesn't matter. Pluto's not a planet anymore. And yeah, this is kind of what I thought of the solar system when I was growing up. But it turns out that this is not a complete picture of the solar system. The solar system looks more like this. Each line and dot here represents one minor planet on the solar system. I think there are a million objects in this image. I'm not really sure there's a lot going on here. And let me just point you a few things. So here is Mercury. This blue line here is the Earth. Then we have this thing, which is the asteroid belt. Once we go farther, we still have a few minor bodies. We have this region where the giant planets are where we have a bunch of things. And then this faint blue line here is Neptune. And beyond Neptune we have a bunch of stuff. And this is the region of the sources that I'll talk about, which is called the Translipton region. So let me show you a little bit of the history of the sources. The solar system formed from a disk of gas and dust and etcetera that was collapsing. From this collapse the planets formed and they didn't form where they are now. They're forming different places in their current orbits. And once this thing happened, this planet, we call this a migration.  In particular they kicked things to the outside of the solar system, which is what we call this Transliptonian object. And they also kicked things even farther in a region that we call the Earth cloud. The Earth cloud is one of the main regions where planets come from. So this is a little bit of what I'm going to talk about here. So we went from this thing to this thing in something like five billion years. And this is the modern view that we have of the sources. So we have Earth. The Earth is one AU away from the Sun. AU is the definition of the Earth. So I'll be talking about this thing. Every time that I say something AU, just saying X times farther from the Sun than the Earth. So I'm going to be talking about 30 AU all the time, which is this Neptune. So that means 30 types farther from the Sun than the Earth. We have the asteroid belt that I just talked about here.  We have the Kuiper belt and the Transliptonian objects. We're trying this region here. And then these things are still in somewhat of a disk shape. And once you go farther, we have a spherical cloud of objects, which is the Earth cloud that goes as far as tens of thousands of AU. So for reference, this is something like half the idea. So yeah, the work cloud is pretty big. Just a little bit of historical context. First asteroids were discovered in the 1700s. The first Transliptonian object Pluto was discovered in 1930. And the second one was only discovered in 1982. So it took us something like 60 years to start discovering these things. And now we know about 3,000 to 4,000 bills. Now, comments, I won't tell you how many there are because it wasn't a trivia. If you got it right, you know the answer. Let me show you what these things look like. These two images represent the largest and one of the smallest objects in the Transliptonian region I've ever found. This is Pluto, the dwarf planet. And this is Erika. These two images were taken from the Kuiper belt from the Transliptonian region by the NASA New Horizons probe. So this thing was launched in 2008, if I'm not mistaken. And it took several years to get to Pluto. It took a few images of Pluto and then it was maneuvered with some complicated stuff that you don't understand until it took images of Erika. And this represents what these bodies look like in the solar system. So you can see that Pluto has lots of features. It has the pretty heart here. So there's a lot going on. And Erika is also a very interesting shape. It's an interesting shape body. The binary has this globe and this globe, and it has something like a 30-ton diameter. So you can imagine that there are lots of things going on between in this size. So this gives you a good idea of what the size of these things look like. And as I said earlier, we don't have 3,000 of these things. Now, comments look so much different from that. Comments are typically smaller. The whole reason here is that as they go closer to the sun, their material burns up. That's why we see them being pretty in images. You were showing an image of Hayobot earlier, and you can see that there is the tail and the comb, and et cetera. This is basically ice being something we made on the surface. The thing that goes to the sun, the material gets hot, and then it evaporates. This is basically what's happening. And this image was taken from both the stomachs, from a bee, I won't try to tell those names for the heart. And this thing has a diameter of about 4,000. So yeah, the key takeaway here is that comments are typically small. And these things are typically bigger. All right. So we try to find things in the outer solar system because they tell us how the solar system burns. I was telling you about this beautiful story where the planets form in different orbits and whatever, and then they migrate, and that's where they are now. And the reason why we know that is because we've been studying objects in the outer solar system and trying to figure out how they got to where they are today, basically. We know that they exist, so we had to come up with an explanation, and this is why we try to find these things. So this was basically my PhD project. I was developing a methodology to discover these things in a project called the Dark Planetary Survey. As you can imagine from the name, this is not a solar system project. This was a project that was made to find hundreds of millions of galaxies and understand basically how the universe worked. But one cool thing is that the sky is just one day, so every time we take an image of the sky, we are seeing not only galaxies and stars or whatever in the background, but we're also seeing things close by. We see asteroids, we see translucent objects, and unfortunately, we see things like stars and stuff. So DS started taking images of the sky in something like 2012. It took images during six years, and we covered basically one day for this time, so it's a pretty big area. DS is a large international collaboration. We have people from eight different countries. I don't remember all of them, far off my head. But one important thing is that there's a lot of people in the US that want to be DS. This is the telescope that we used. It's the Blackfoot Telescope in Chile. It has a 4-meter diameter, and it has a very beautiful camera. The history of this image here is for the dark energy camera, and this camera has something like 500 megapixels, so you can imagine taking multiple copies of your iPhone camera and placing them on the same thing and taking an image revolving simultaneously is basically what this camera does. And this is what our images look like from DS. This is one of the images of the discovery of one interesting transition in an object that I found, and if you look at this image, it's quite obvious that you can't really see what is going on here. There's a bunch of stuff, and you can't really identify what is going on. So let me try to make, like, easier for you, and let me walk you through where the thing is. So the thing is in this little square here, this is one of the smaller pieces of camera that we have in the thing, and let me zoom in, and you can see that there's still a lot going on. There are stars everywhere. There's this galaxy here. There's a cosmic ray that is something hitting the camera and giving a weird shape that's something we don't want in our data, but we tend to get rid of them. So basically in images like this, we have to try and find something. And this is where the object is, and I don't think you can see it. I believe I do, but that might just be because I know where the thing is. So let me zoom in again. And this is what the thing looks like. So now if you think of that image of Pluto that you had in your head a few minutes, that I showed a few minutes ago, and this is quite disappointing because I can really see a thing here. It's not just the projector. It looks better than a computer screen. So yeah, we have images of this thing from 2014 to 2015, and basically from mine of the images, it looks like this, and it's still incredibly disappointing. That's part of life. Welcome to astronomy. Things don't look pretty.  No, that's not true. Some things look pretty in images. But yeah. So this is a video that we put together to basically explain to you how we find things in our data. As I said earlier, this project is not meant to find things in the solar system, so we have to work hard to do that. It's a large computational problem. Let me start the video. So the idea, let me just see if the video's working. Yeah, the video's working. So the idea is then we have to find things that are moving between images. What happens is that things in the solar system, they don't stay in the same place during years of observation. They move. This is a combination of both the object moving around the sun and also the motion of the earth. So that's why the things move in the images. And they look something like this. So we have to basically find where these things are and try to find future images and see if the positions that we have measured the object made sense with something that is moving in the solar system. So we had this catalog of things that are probably moving. We did a technique that is basically the spiritual successor to what white tombow did in 1930s to find food health. Sorry. Where we basically were comparing motion images to see if something moved. Of course, we did this using computers and not by i-light. Tombow did it in 1930, but yeah. And then we played the world's hardest connect the dots problem, where we basically went through all the dots and saw if they had something else that looked like a real source of the garbage. And I said that this is a massive computational problem and this took us 20 million CPU hours. If you're not used to this term, CPU hours, this means that I had to leave a single computer working on this problem during 2,000 years to solve this problem. Of course, I didn't wait for 2,000 years because it didn't start. This project when Jesus was alive. But we solved this by using basically hundreds of computers. And yeah, once we find these things and put actions in their images, we can go ahead and try to say what the orbit is. So this is what this preview is showing, basically. And you can see that there's a lot of stuff going on. You find things basically where it lives on the sky. And then they go everywhere. Sorry, I was just asking my wife to bring my gear. Sorry, my throat is a little bit too dry. But yeah, once we finish this thing after finding if we're going through millions and millions of different combinations of something that looked like a real-source system object, at the end of the day, we had 814 things. And as I said earlier, we know about 3,000 percent of an object. And so this is basically saying that I found something like a fork of the total, which is pretty impressive. And something I'm really proud of. Just to give you a sense of scale, because this image is rather confusing if you've never seen anything like this before, each line here is showing the orbit of one of these things in the source system. And here is a zoomed-in view. So I'm going from this little circle here to this thing, which is showing basically the closest things we found in our data. So here is Neptune, and then the other planets that I don't really care about. And then this purple thing here is the type of it. So this is the bulk of the trans-definition region. This is where most of the things that we found live. So yeah, you can see that there's a lot going on here. And maybe you've already seen it, but there is something that doesn't look like the rest of the things here. This thing has a completely different orbit, which means that there is something quite interesting going on here. So let me zoom out again, and this is what the orbit of this thing actually looks like. So we're going from here where Neptune is to here, which is what the actual orbit of this thing looks like. So this is an orbit that comes from the Earth Cloud. The Earth Cloud, as I said earlier, is basically a spherical region. We know that things come in from there, because we see them, but we have never actually seen something in the Earth Cloud. And the reason for this is that things in the Earth Cloud are small. And because things get incredibly far, as you can see here, so the hardest point of this orbit is something like capital idea. So this is really far from Earth or anything else that goes into the Earth. So it basically catches things if they come close to it. Yeah, so this object has its closest point to the orbit to the Sun in 2031. So this means that we have another 9.5 years to observe this thing before it actually reaches its closest point in its orbit. And then we have another 10 years before it gets too far for us to be able to actually see it. And this is at a distance of 10.98, basically. This is a little bit further than Saturn. Saturn's distance to the Sun is 9.7 or something like that. It's a number that I know it's around that thing, but I don't really know the number. And this thing has an orbit with a period of about 3.5 million years. So basically the last time that it came close to the solar system was 3.7 million years ago. And then we have another 20 years to observe it, and then it's gone whenever seen again. This is one of the sad things about observing planets. We don't really have a lot of time to watch them. Typically we have something like a year or two before they get too far from the Sun, and we don't see them ever again. In the trivia, they were talking about hellbottom. And basically hellbottom we could see from the naked eye during two years that I don't actually know the number of months where it was visible. But we saw it from two years and now it's gone and we'll never see it again. This is another case of something like this happening. In 2040, this thing would be impossible to observe and it would be gone. Which is a little bit sad, but you know that's part of it. So why is this thing a big deal? We know the comments exist. We know a thousand of them. And people find comments basically every week. The reason why this is a big deal is because this thing is incredibly big. So these are the two largest comments that we know of. The first one is hellbottom. It was discovered in 1985. It has a diameter of 74 kilometers or something miles if you use this barbaric unit system. Sorry, I'm not American so I'm not used to markets. And the second largest comment is this comment here called Paraback. This was discovered in 1729 by a French priest, I think. And this is the only image we have of it. So 300 years ago we didn't have visual cameras. So these things were drawn by eye with incredibly detailed precision and etc. And this thing had about 100 kilometers of diameter. We don't really know if this is the right number because basically people were seeing this thing by eye. Well, they had to estimate how bright the thing was. It's obviously not precision science that Korea is just saying. And why are these things so rad then? The reason is that, I showed you earlier the protoplanetary disk from the solar system, the processes that went through there formed a lot more small objects than big ones. Basically there are some complicated physics that I don't really understand and most people don't really understand that go through these things. And we formed thousands of small objects and just a few big ones. So in other words, big objects are rare in the solar system. That's why we don't have eight planets with me as an answer. And then there's this comment here. This is an image. I told you that images were going to be disappointing and this is another one. Even though this is a really pretty image, the actual comment is just a dot that you can barely see in this projector. And a few cool things about this comment. The first thing is that it's exceptionally bright for its distance and this is already telling you that the thing is pretty big. When we see something in the solar system we don't really see it emitting light. We see the light that reflects from the sun. So if the thing is bright, it means that it's big. This is rule one of observing things in the solar system, basically. And also this happens to be the most distant comment I've ever found. This was found at a distance of 29 AU which is basically an actual distance and most comments are found when they got closer to 5 AU. So this is why I'm saying that, hey, it's cool we're going to have like 40 years, 20 years to observe this thing until 2040. This is the reason. We found it extremely far from the sun which is something that doesn't happen every day so this is quite amazing. And I told you that this thing was probably big. So by combining both data taken with optical telescopes, this image here and with thermal telescopes which is this image here we've been able to determine that this comment has a value of 137 AU which is basically twice as big as this one which makes this door just comment every time which is something cool to say that I was able to do. Oh, by the way, this is interesting thing about rules of naming comments. Comments get named after their discoverers so that's why this thing has my last name. Yeah, I get to brag about that. That's cool.  I showed you earlier comment 67P. This is that comment and image. I also showed you IRICOP and that's where this thing is. And this is Enceladus or Enceladus I'm not sure what it's the proper pronunciation. One of the moons of the giant planet in the solar system and this is this comment that I discovered. So this thing is pretty big. It's almost as big as the moons that we've seen in the giant planet. And once again this big things are rare so this is quite a fascinating find. And it has attracted a lot of attention both from professional and amateur astronomers I'll show you some images later on and also from media. During the second half of last year I think I gave something like 15 interviews to journal news articles and a tetra everywhere and it was honestly quite annoying because every day I would get an email from someone saying hey I'm a journalist in journal whatever can you talk to me about this thing? And you know the first 10 were fine but after several of those it got a bit tiring. And yeah so I'm going to skip this one for now I'll go back to you later. This thing got announced mid June last year I think it was June 19th and within a few days basically everyone that had a telescope ready took an image of it. So this one was taken June 19th, June 24th this one was June 22nd so basically people that had access telescopes took images of it which was something quite fascinating and let me go back to these images here this is a combination of images taken by the energy survey and once again it is really disappointing compared to what it would expect to see from a comet. In particular because in these images you don't really see the tail that it would expect to see in a comet. And this was something that puzzled me for a really long time. This thing is really a comet we know from its orbit we know from images taken nowadays that it has even a little tail here I don't know if you can see it it's a bit hard but it does have something like that. So why are we not seeing it in these images? And it turns out that the tail of this thing is incredibly faint and it didn't develop until it was a distance of about 26 AU so this is an image of the thing at 26 AU in the closer and you can see something a little bit here this is really faint and really hard to detect and that's something that we were quite happy to see in the data because basically we saw a comet turning off and this is the first time that we see something like that. Once again because we only see comets closer to the sun we only see them when they're well developed so this is basically the first time that we've ever been able to measure something like that. And these images that are from 2021 are way prettier than these ones. But yeah, that's basically all I had we can chat and talk about this thing so just to summarize what I talked about this is an incredible comet that was found basically by accident we were looking for a different type of object and we found this thing because it was there which is something that happens a lot in astronomy but it always do when it happens and we have a chance to study this comet in detail for the next 20 years or so until it's gone and we'll never see it again and if you follow XKCD the proudest moment of my life was in XKCD with this comet showed up thank you thank you so much you all should have been taken care of so what we're going to do now is announce trivia so I'm going to put this microphone down for a second and I'm going to go up and switch our slides to the trivia slide so I can walk through the answers and then I'm going to announce let's let Pedro answer some questions first sorry about that no problem so if anybody has questions can I come back to Pedro and I'll just clap hand in hand with the question and answer period I'll just pop up yeah alright if anyone I think it's easier if you walk here and speak on the microphone so I can actually hear you yeah stay on the microphone so everyone hears you as well or if you just want to shout then I can repeat it alright that is a good question so the question is if there is a maximum size we don't know let me go back a few slides this thing is 95p Chiron it's a Centaur it means that it inhabits basically the region of it where the giant planets are and this thing looks like a comet it has some things that are called activity it has outbursts which basically means that it's kicking ice out and this is something like 200 kilometers in diameter so this is the largest thing that we found but we don't know if there is a maximum size anyone else go as close as you want and then shout it easier that's a good question so the question is how many there are total in the transinfinite region and we expect there to be something about 100,000 of these objects larger than 10 kilometers or so we don't really know the number this is somewhat of an observing effect it's hard to find smaller things and there are more smaller things than big ones but also because we haven't really measured the size of the business the expected number is on the order of 100,000 and in the next decade or so we are trying to find something like 50,000 of those so we'll know in 10 years what did the actual number do so the question is if comets eventually do burn up and disintegrate and the answer is yes as they get close to the sun they warm up and start building many ice and the closer that they get more material evaporate and eventually they just disintegrate we have seen that I think there was a comment that was here I'm not mistaken and that's something really cool that we've seen in images we basically see we take an image of the thing, it's one in one piece, we see a few months later it basically has a bunch of pieces and that's something that's quite hard to track comets also die if they hit the planet or they hit the sun that's a bunch of things we have measured as well and also because these things are losing mass they basically speed up a little bit and they can be ejected from the solar system so they don't really die they basically never come back because they were kicked out of the solar system so the question is what type of observation you need to determine an orbit to determine an orbit of these things you basically have to keep moving so let me go back a couple of slides to this slide this is a bunch of images taken between November 2011 and December of 2015 so this is the type of thing that we need we need to see it across a few months and then we're able to actually tell that it's moving so why do we need to see across a few months and ideally between different years the motion of these things is dictated on the sky is dictated by the motion of the Earth so basically what we see when these things move is the projection of the motion of the Earth so if you see it across different years you're basically seeing the Earth being this object from different places and that's how we can track it down but ideally you need something like several years of data to be able to say really well what the orbit of the thing is so the question is what to look for in 2031 for this thing and the answer is that there are several things that we're trying to do with this progress so the first thing is we're trying to determine what types of materials it has in its surface and what materials are being evaporated the idea here is that once comments get closer than 5 AU they start sublimating water and that's how we thought of promising to something like 10 years ago now that we know the comments have activity up to 20 something AU what types of materials have been seen we don't really know what type of material caused it so that's one of the things that people are trying to figure out about promising is what type of ice that we have in this object that makes it evaporate as far from the sun as 20 so this is one of the things that we're looking for of course because we have a lot of time we can also do things like see how its brightness changes as a function of time for example if it's rotating brightness will fluctuate and that's another thing that we're trying to do nowadays so basically is it rotating what kind of shape it has and all sorts of questions like this that is a great question and the answer is basically what makes HD1 so the question is what was the motivation to do search for objects like this given the original rules of the vacuum energy survey there are a few ways to answer this question the first one is basically we knew we could so why not try but also you need some sort of deeper motivation than just we can do this so a few years back there's been this discussion about the possibility of an ice planet in solar system that's something that's still an open question in the field and I've given a sermon that I've talked about this so you know I won't say too much about it here but the idea is that there might be an ice planet in the solar system that we haven't found yet and one of the motivations of trying to find objects like this was that we could basically try to search for this thing directly or if not see it basically say a little bit more we expected it to exist or not our answer is that it's not there to find it but because we've done some analysis saying that hey yeah if this thing existed things would look different in the solar system so this is one of the key pieces of motivation but this is one of the beautiful things about astronomy is that when we have this large sky surveys we can do lots of different sciences with it we've done the solar system stuff that was very rewarding but we've also found lots of different structures in the Milky Way that have not been seen before people are finding all sorts of real galaxies and etc so that's what you get when you measure basically one at the side you get to see all sorts of things that you're going to expect one more question no one, alright thanks everyone okay for the next one and just three diagrams okay okay great for sure now as a very you have astronomy grad students andes and adachis andes is a first year astronomy phd student at the University of Washington andes research focuses on the observational properties of stars using large data sets an ideal evening for andes if you wanted to know includes cooking oh sorry cooking not just cooking eating donuts and communicating science with the world and that's all of you so give a big round of applause for Andy thank you well thank you cheers everybody really nice alright I'm going to need a couple more beers here alright how are y'all doing tonight yeah alright let me just hold on microphone is falling off here alright can anyone hear me in the back alright good alright so let's get started here so today we're going to talk about fields of astronomy you probably never heard of so let's just do a metrography strange word we're going to talk about the dynamic universe and I really want to take you on a trip into the universe perhaps like a new lens of really viewing the world around us so let's get started here um I really want to take you on a journey to a place in the universe that you might not expect are we going to raise our hands here how many of you have been to New York or have lived in New York yeah New York is awesome I'm from New York so ok so here's the question I have for you all suppose you had this image of New York and it asked you does this picture fully represent the spirit of New York City or any big city really right no right well it looks a little suspicious right you have some like happy people walking around but you know as any New Yorker would tell you that's not never the truth there's some taxis and stuff like that right but that's really not the full picture right you need something more right ok the reality is that New York is this dynamic place right the center of so many cultures and people coming together right here's a great place and any good New Yorker would tell you that no two days are the same right so a lot of weird stuff are happening in New York a lot of exciting things like for example you have rats stealing your pizza like that's pretty messed up yeah you have commuters like putting their pets in like I don't know what that is but yeah I'll go with it I'll go with it and you have people dressed up as Christmas trees in the subway I mean like I'm not making this stuff up like if you've ever been to New York like this is actually like real life but the point I want to make here is that no two days in New York are the same and so therefore New York is this dynamic place many exciting things are happening at once and so yes you predicted correctly I will say that the universe is very much like New York and that's possibly the most New York thing I've ever said in my entire life right if I asked are there astronomers here in the room or all of you do you think that this picture here fully represents the spirit of the universe if it gives us a full picture of what the universe actually is what do you all think no right yeah exactly there's a lot more exciting things in the universe and for many reasons we see a lot of pictures of the universe and they're just still images but the main thing is that oh there's an alien here too yeah it says waves high right there's a lot of exciting things happening in the universe right you could see stars you could see galaxies you could see all sorts of exciting things but what I want you to remember from this talk is that the universe is changing and the universe is changing with time so my goal today is to kind of tell you the story of how we think of this changing universe and why this question is really so important has taught us so many important lessons throughout history okay so we're gonna kind of take a journey here and really understand a lot about this changing universe but remember that the universe is always changing with time okay so alright you're like hold on Andy you're giving me too much information you're telling me that the universe is changing like how did we even get to that conclusion that's a lot to process so don't feel bad because people have only known about this for 2,000 years so you should get on to this but yeah we humans have really been observing the night sky for more than 2,000 years but we've been seeing documentations of things happening in the night sky for over 2,000 years so Chinese astronomers in the Han dynasty would see these stars they call them the guest stars and they would be as bright as the full moon and they would last for like a few months indigenous Americans would see things where they documented here this point is right over here and they signed it too like hey we saw this we saw this first but the point is that throughout the history of time we've seen a lot of things change in the night sky and what I want you to remember from this is that in order to see the night sky change you're like Andy when I go outside I look at the stars and nothing changes it looks like the same old boring sky and you're like well the point is here that you actually need to look for a long time to actually things change you really need to be staring at the night sky in order to see these changes happen so we're going to go through all these different kinds of changes that we will talk to you so a few moments later and by a few moments later I'm talking about more like a thousand years or so we're going to kind of zoom out we're going to take a little tour of our universe so right now we just left New York City so buckle up and now we're in the solar system so welcome to the solar system so now I picked a particular story that I loved so here we go 1930 American astronomer Clyde Tumball here he is looking pretty good with his telescope all chill Clyde found something now in the audience if you know who Clyde is you can look at it for the rest of us but Clyde found something and I really all want you to get that experience of joy of what Clyde found and so a little bit of context at the time he was using these telescopes and he used these photographic plates that you would find on these telescopes and you would take pictures of the night sky and he used this machine here which is called a blink comparator and all that is it's basically that you take two images back in the day you took photographic plates of the night sky and you can compare the two images to see what would change so Clyde did this and he found something so this is not part of the official trivia but I want to see if anyone can find what Clyde found and again don't spoil it if you could see it ok so I'm going to show you two series of images warning there is some flashing going on so if you're sensitive please look away and try to see if you could find what Clyde found and oh one thing before I go between the images you'll see that the night sky is kind of these stars that we're seeing here are going to be kind of changing right and one thing that we need to keep in mind is that the weather conditions that when you're taking these pictures is not always the same so that's why you might get seeing like all sorts of weird stuff happening with these stars ok so are we all ready? so when you see it maybe raise your hand and I'll maybe call on you to ask you where it is ok alright alright ready go can you see it where oh let me get someone where where maybe someone in the back screaming out loud is like in the center bottom where bottom what yeah I'm not authorized to tell you what that is where upper middle ok oh ok I hear some good thoughts ok so upper middle yeah you passed the astronomy test good job by the way do you know what you just discovered a planet at the time though just to be aware right unfortunately Pluto is not a planet anymore let's get past that but Pluto is a great system yeah purple it off ok so obviously you know Pedro's talk really motivated this idea of like why do we need to study the solar system and why does the solar system really contain all these yeah these bodies that we could study and really you know there's a myriad of many many asteroids and meteors that are going around their solar system and so even our own neighborhood our solar system is really dynamic there's a lot of things going on and I really hope I don't need to motivate why it's important to know like where all these asteroids are and what they're doing right like I don't know if you've ever heard of this story before but yeah we definitely need to know where they are so that that's that's one important thing but kind of on a more serious topic right we want to take of an inventory of like where all these asteroids are and meteors are because that gives us an idea of you know the formation of the Milky Way some of these objects are as old as the solar system so understanding where these objects are studying their light and how how it changes right can tell us a lot about the shapes of these objects and possibly about the the solar system itself okay so we're going to zoom out even further now now we're going to go into the stars and stars are my favorite topic stars are like the coolest thing ever okay so our story here begins in the early 1900s and we had Juan Leavitt she was an incredible American astronomer and so around that time her collaborators in her were studying these bizarre stars in a neighboring galaxy which was called the Magellanic Clouds and so this is obviously not the scale right but our galaxy turns out that we have these neighboring dwarf galaxies that are kind of going around us and so they were studying the properties of the stars and how these stars changed and so at the time they realized that something weird was going on so this is an image of a galaxy of these stars and what you'll see is that these stars are flickering now let me give you a little bit of context right at the time astronomers didn't know that much about the Magellanic Clouds so this was kind of like next level stuff like you see this and you're like oh crap I don't know it's really difficult to understand so it turns out that what they were looking at is a kind of stars which are called thepian stars and thepian stars are kind of these interesting stars and here I'm going to show you a diagram of the brightness of the star as a function of time so let's see what that looks like so what they found was that the star actually has a sort of periodic behavior right it goes bright and faint and it really just competes the cycle but one of the most amazing discoveries at the time was that Henrietta realized that if you were to look at the cycle that it takes the amount of time it takes to go from one top right to the full cycle that that almost perfectly correlates with the brightness of the star now you're all looking at me like alright like what does that mean like complete silence but the astronomers in the room know that that's actually really important because what this means is that we can actually measure the distance to these stars and so these symbiotic stars become like a measuring step in our universe and distances in astronomy are really difficult it's a very sore topic you know if you ever want to like get an astronomer all like uncomfortable it's still like how do you calculate the distances in the universe right and so this was a pretty big deal that she discovered so this is really important thing but a few years later comes another dude Edwin Hubble does that ring a bell? yeah so Edwin at the time hears about the discovery and he's like cool like that's a that's a pretty neat idea I think at the time he was working as a janitor at the mountain observatory and then eventually like convince like the person to like let him observe these stars so Edwin Hubble was interested in looking for these stars in distant galaxies and he was actually the first one to realize that the closest galaxy to us the Andromeda galaxy was actually a galaxy in the first place fun fact if you're ever in Los Angeles California go to the Mount Wilson Observatory it's on a hundred one hundred inch telescope single piece of glass the thing is ginormous and on public outreach nights they even let you like even look through the eyepiece and so you can tell your friends that you you know you're a cool astronomer whatever okay so Hubble oh I guess that gives a punchline away but anyways so Hubble makes this pretty interesting discovery right using this this this concept of the city of stars so he tries to discover the city of stars in distant galaxies so here I'm going to show you a diagram of the velocity so healthy how fast things are moving away from us as the function of this so distance velocity okay so Hubble begins to do his search on the city of stars and because we kind of know because we can measure the period of the city of stars we can kind of infer a distance and measure the velocity so you know the first few data points come in yeah looking good looking good looking even better oh crap there's a straight line now for my astronomers out there when you have things that look like a straight line it's a good day you know the universe when you can express the universe in a straight line you know that's a good day but what what Hubble really found was that punchline the universe is expanding the further away we looked into the universe the faster things are moving and so this is a fascinating discovery right and so we went from a simple concept as the changing night sky to an expanding universe so really take a second to internalize how amazing that is okay uh oh an analogy that astronomer would love to give is that imagine if you were baking bread with raisins as you're baking the bread the separation between each raisins the raisin would like increase but I hate to use this analogy because it makes me really hungry I really like bread so yeah so yeah there you go okay but obviously there are a lot more stars than just your simple sipid stars right there are all kinds of stars and this diagram is pretty complicated to explain right like you know this is basically like color and like brightness but the point here is that there's many many kinds of stars there are some of the pretty ordinary stars it's called a dwarf made sequence star but there are all sorts of weird things right there's like red giant branch stars that but the point is that when you look at the brightness of these stars as if they changed they can tell us a lot about the physical processes that govern these stars and can really give us a lot insight into you know what are the physical mechanisms that govern these stars so a lot of stars out there a lot of things to learn about the changing ice guys so there's not only sipid stars that are changing but there are many different kinds of stars so we could do this we're gonna find the same concept too okay we're going out now even further now you're like Andy okay like what else can change in the universe okay we have stars okay many galaxies like the galaxies change let's see okay here's a pretty amazing statement let's hear let's get a little silence here every second there's at least one star in the universe that's going boom can you hear it now I'm not sure if I can hear it okay so it's a pretty pretty big statement right but what is what does it even mean like what is what is a supernova what are what's going on okay so at the time this was a couple decades ago there's this Swiss astronomer his name is Fritz Wickey and you know his name is a pretty controversial figure you know he used to call astronomers spherical bastards if you just google that term it's basically that no matter what way you look at astronomers are bastards very very strange stuff but nonetheless he was a genius in realizing that the only way we can really understand the changing night sky is that if we actually use our telescopes to kind of survey the sky we really need to have an unblinking eye in order to catch these amazing things that are happening in the universe that are changing and so you know him and his collaborators started this this survey to look for you know all sorts of supernovae that are taking place and fun fact these are some super oh no these are some supernovae that I discovered right it turns out that Fritz Wickey was right like yeah it's amazing like you could discover these things all the time so like you know you could discover a supernova and get a supernova yeah pretty cool okay what are supernovae in the first slide that was the other slide okay so there are flavors of supernova I swear to you this is not an ad for ice cream yeah it looks kind of yeah I don't know I don't want to talk to you but anyways there are two kinds of supernova you have your thermonuclear supernova so you this usually involves and this is again theoretical but this involves two stars and you have usually one really big star that's donating mass to a compact object and then as it's creating all this different material it's sucking in all the material basically you can get these explosions because it reaches really high pressures and temperatures and then on the other side the core collapse supernovae are these really big stars right and when they reach the end of their life they no longer have fuel to kind of maintain the gravitational pull of their own gravity so they collapse and they go boom and so those are the two flavors if you've ever heard of the phrase star stuff well here you go this is what star stuff is made of so you get a star stuff everybody gets a star stuff right but these are one of the main reasons why we think that the universe has so many different kinds of elements the oxygen in your blood the nitrogen in all different kinds of heavy elements are producing these enormous explosions how do you even discover these right like that's a pretty interesting question so the way you do this is you use a telescope you look at some patch in the sky and you let's say we have an image before let's say we had an image from like last night and now I'm going to take a picture tonight like let's say like one day one night after they have like a before and after now in the hypothetical worlds if nothing had changed these two pictures like if you subtracted this image from the other this would be zero right because nothing has changed if nothing has changed you basically get zero but in fact you get a little dot and that little dot is is a supernova right that's I mean that's really that is like I mean like that's how easy it is to discover supernova so I mean like yeah I don't want to do it yeah we need help there's a lot of them okay but my most my favorite fact about supernovae right single supernova explosion can produce the energy equivalent of our sun after one million years so imagine if the sun was burning for a million years a supernova can release that in a matter of like days or hours so if you've ever had trouble sleeping at night don't worry the universe always has your back for the scariest shit that you could think of yeah so yeah take that the earliest supernova actually the supernova we've known for a while now is 1987A this was the closest one of the most recent supernova that we've known about and the question is can you even see where this is so this is actually in the Magellanic cloud but there's a neighboring gap it's not even in our own galaxy but can you even see where the difference is in this image yeah okay yeah good yeah so that was the most recent supernova that's pretty cool though so astronomers got really excited when that happened the point is though that it turns out that supernova are not the only kinds and flavors of explosions and it really is that there's a lot of kinds of explosions right so supernova and this diagram so this is a diagram that tells us something about how long do these things last for so over here you would have like a hundred days and then this is the vertical axis about how bright they are so the supernova we just talked about kind of lay are just around here now you might have noticed I put some emoji symbol of like money so it turns out that we think that the most exotic kinds of explosions which produced gold and platinum are somewhere around here and believe it or not there are things that are even called koalas and cows of explosions which are all kinds of different weird explosions that are really fast so you see them for like a couple of days and then they disappear from the universe and you can't see them but what you might notice from this diagram is that this diagram is mostly and this really gives us a potential to really explore all kinds of explosions that might tell us about the universe and so our goal is really to understand what kind of explosions are we seeing here and this leads us to the final kind of topic of time domain astronomy time domain sky surveys right we need to use telescopes to understand what's going on in the universe now I might have overwhelmed you a little bit about how much things are happening at the same time and to be honest like I haven't even told you the full picture there's so many more things happening so to overwhelm you even more I want to just zoom in in the Milky Way galaxy to just show you the scale of our own galaxy so here we're just zooming into a picture and you can see for each frame we're going through we're seeing all sorts of stuff so can you imagine keeping track of all of this changing if we really made the argument that like the universe is really changing and there are stars and galaxies and supernovae and all sorts of things do you really think that how are we going to keep track of this right like this was a pretty serious problem so how do astronomers do this so imagine here we're seeing our view of the Milky Way galaxy and we're within the Milky Way galaxy so astronomers what they do is that they survey the night sky and all that is basically is that you can imagine that we have like these little boxes and we basically scan the night sky and we do this you know every night or so right we come in and we take a picture and then you can basically compare these pictures from one night to the other and say like huh what has changed here right is there anything new that's going on so that leads us to this term that here I'll be using alert basically every time a telescope goes to the night sky scans it right it does that technique that I talked about subtracts one image from the other it could basically send you these alerts right say like hey like things have changed so you have let's say an image here which might be a galaxy and that might possibly look like a supernova right so the telescope will do the all those sort of subtractions and stuff like that and you get these what we call detections and then you could track that as time goes on right you can come back to that same point let's say one tonight one the next night and then over time we could basically track how bright these things are as the function of time so here we're just seeing a core collapse supernova right this might be on the scale of 100 days and you can see this fantastic like huge explosion huge gets really bright and then it eventually dies and so this is this is the game that we play which leads us to the most important part of the night so I really want you all to pay attention to this one this leads us to the vera sea Rubin observant now this wouldn't be a complete talk if I didn't mention who Vera Rubin was and I'm going to put a bunch of points here Vera Rubin was an American astronomer she is personally my favorite role model in the field and she has played such a huge important role in female astronomers in the field but she was the first female to gain access to the historic Palomar Observatory which was a really big deal out of time and one of the interesting things is that so originally when we were going to talk about this telescope was called the LSSD Congress decided to rename the telescope as the vera sea Rubin Observatory named after the American astronomer Vera Rubin and at the time Vera Rubin had made a really really important question and discovered and this is, you might have heard of it dark matter that's a pretty big deal okay so I want to really just go on a rant a little bit about what is dark matter maybe you might have heard of this story but I really want to tell you about it really quick okay so how do stars move around galaxies let me give you like an intro to like physics really quick but like I promise you this is the only equation that you'll ever see in this talk but basically the way stars move around galaxies just depends so the speed of a star depends on the mass that's enclosed within the galaxy so you can imagine that as the star goes around the speed of that star depends on just basically the mass that's enclosed within that circle of its orbit and then you divide it by the radius okay pretty easy stuff right so here on the bottom we have a diagram of the velocity against the distance and it's basically describes what we've talked about right we start let's say like a star starts at the center of the galaxy right because it's not a lot of mass it's not moving a bunch but as you go further and further out you're seeing more matter right there's a lot more stuff happening there's more stuff in the galaxy and then you go out to a point where you're still far away from the galaxy when the speed eventually drops so Vera Rubin had the idea to look at the speeds of objects in the galaxy and so you know they start out and you're like okay good so these are their measurements like all is good all is good this is a good day for astronomers so all good all is good whoa whoa whoa what is happening here that does not look right to me right so what's happening here is that whoa the speed of stars is not slowing down but instead they seem to be fixed and the only way you can explain that is that if you had more matter right because as we're going further out into the galaxy you don't have that we don't see that much mass right and so the only way you can explain that is if there was some invincible mass that is dominating this galaxy and so that's why we're seeing that the velocity of stars is not dropping but instead it's almost holding a steady base right so this was you know this makes astronomers angry this makes the conspiracy theorists angry you have aliens I don't know but the best explanation to this is well dark matter it might be dark matter that we just don't know about yet and this is by the way an unsolved question in astronomy so if you have any idea you know let me know it's worth a lot of money but cool so this leads us to the final journey the Vera Rubin Observatory fun fact when astronomers use the word era that's a really important thing right like if you're like era important okay so we have this amazing telescope that many institutions around the world including the University of Washington is leading and this thing is next level let me tell you you'll also hear me call refer to this telescope as the LSST it's the legacy of survey of space and time but yeah I'll be using these names so you have this telescope that's currently in construction and it's going to be surveying the night sky in the southern hemisphere so this is located in Chile and it's going to be looking at the night sky going to be basically surveying and trying to see what things change here is a picture of the telescope beautiful this is the night sky I was looking at I mean it's basically almost done and I really want to say that this wouldn't be possible for all the amazing engineers and scientists that have made this project come to life and I mean really this is an incredible experiment that's going to be happening so you know the telescope is ready to go it's mounted and stuff you can see the observatory here in the beautiful north Andes some facts about the telescope now obviously we're all very excited about the telescope you can ask any U-dub student about this a lot of the faculty and students are working on science projects that this observatory is going to be making but I want to give you I want to really blow your mind on how next level this thing is so the telescope is 8.4 meters which is 27.6 gigantic like yeah I don't even know how that is but really good we're going to also be doing this 10 years that's a really long time so we're going to be looking at the universe for 10 years and we're going to be making this incredible movie of the night sky changing for 10 years and the best part what we expect at the first light is going to be around 2023 so next year great year for many reasons and here you can even see some little figures that I put up how big this thing is right the gigantic telescope that will give you a lot of amazing science okay so for all my nerds out there I compiled some statistics for you guys just blow the minds a little bit okay so on an average night the telescope will deliver 20 terabytes worth of data I don't know if that means a lot but basically a smartphone wouldn't be able to even hold that much information after the 10 years survey we're just expected that the telescope will be able to accumulate around more than 15 petabytes worth of data I don't know if that's impressive for my Amazon people here but for astronomers this is a pretty big deal we've been looking at photographic plates and really small data sets for a while this is very overwhelming for astronomers another thing is that we expect about 10 million alerts per night so you better keep your phone on mute or else you will never be going to sleep because there's going to be a lot of things changing right there's 10 millions a lot and hear this you'll be getting alerts of the sky changing every 60 seconds so can you just imagine your phone like bing bing bing bing bing that'll just be very annoying to think about but that just gives you an idea of the scale of this project just because we have such a big telescope and they will be able to probe the changing sky who do you think has the world's largest camera right now astronomers yes correct so they're going to be mounting it on this telescope this gigantic telescope they're putting the world's largest camera the camera is 3.2 gigapixels I don't know if I've ever heard of that but like it's 250 times more sensitive than your smartphone so very very sensitive camera very big camera the camera I think is like the size of a car that's what they say really big camera very impressive hear this it will take 337 4k high definition TVs to display one image yeah I know like that's very overwhelming but okay this is pretty cool what do you think the scientists that when they were commissioning this camera when they were testing out the camera what did you think was the first picture that they took the picture of a piece of broccoli this might be here the most expensive piece of broccoli you've ever seen the most expensive picture you've seen of broccoli it's technically Romanesco which is kind of broccoli but here are the scientists putting the piece of broccoli like the world's most expensive advanced camera that humanity ever built like yeah pretty cool stuff you're never going to see a picture like that before the camera is pretty cool the camera is truly a feat of technology just to give you a more a scale of like the mirror itself one image will be able to fit 40 full moons so take your full moon 40 times that's a big patch of area and I know this is more about the camera but if you were to distance yourself 15 miles away from the surface of the earth you would be able to resolve a golf ball yeah that's pretty next level and now we have these filters and so this is going to be the first survey that's going to be doing this in all sorts of kind of filters obviously there's many other surveys that have done this in other filters but this is going to be including also all these kind of filters and what these filters will do is that basically we're going to be looking at the universe not only in a single color but we're going to be looking at a different kind of colors and different colors tell us something about the competition of these objects that we're going to be looking at tell us something about the physics of these objects and you can tell us a lot of exciting things that we will learn from so this is just showing you how that mechanism would work and you can block out the light to kind of see all different things okay which leads us to the full circle now we have finally arrived to a static image and so this is perhaps maybe something what it would look like this is from a different survey but you can imagine this is what the universe would look like but as you all remembered from this talk the universe cannot be fully represented by this image but instead maybe after 10 years the Vera Rubin Observatory will be able to transform this picture from that static image to something like this where you have all kinds of things and exciting things happening all over the place you can see stars and you can see supernova and you can see asteroid flying all over the place and the amazing thing is that over the 10 years that the Vera Rubin Observatory will be surveying this guy will be making all these amazing discoveries about the universe which leads me to the last problem that I'll leave you all with and this is called the needle in the haystack now this is of course very overwhelming and there's a lot of things happening in the universe the universe is a very busy place and so given our very finite resources here on the earth maybe you've heard of the telescope James Webb Space Telescope the most powerful telescope in the world these are very finite resources and amongst the myriad of many many different kinds of objects that we see in the universe the universe in many ways is both ordinary and extraordinary there are things that are happening that we kind of know about but the question is how will we be able to tell the things that are extremely unique and important because there's going to be just so much information happening and so astronomers are really baffled by this question and this is a question that astronomers are going to be working in the next decade as this telescope will start to begin to collect data so I really want you to think about all the amazing possibilities that we can discover really the changing night sky is really full of discoveries and things that we just don't know yet about and so there's a lot of potential for us to understand things that we don't know about and all the things that I've discussed the very movement observatory will be able to answer and give us some more insight onto so I'll leave this here if you have questions please make sure to ask me but if you if I don't get your questions make sure to come and talk to me after and thank you all so much again okay oh yeah questions alright alright go for it let's see do you have any questions in the in the audience a lot a lot to handle all that great though silence yeah come on I've put to sleep everyone's roll yeah here question oh what's the plan of handling all the alerts that's a good question um well the good thing is that what we will be doing is that we'll be sending these alerts to kind of like a thing that I was introduced to is called like kind of like the facebook for astronomers so you can imagine that we'll be streaming these alerts into these what we call brokers and using these brokers you can basically kind of you know do all sorts of science experiments now I really only tap the surface here of like all the amazing science that you could do but you can imagine like if a group was interested in like supernovae for example you would only be looking for supernovae so you could use these brokers to kind of use all sorts of parameters for the star and kind of say okay like I'm only interested in the supernovae and using that now one astronomer doesn't always deal with the whole data set itself so you look at a very specific thing that you're interested in that's a good question it's very overwhelming for sure yeah I'm sorry I have to repeat the question yeah yeah yeah yeah that's a great question yeah this goes back to this this needle in the haystack problem yeah yeah yeah so the question was how will we be able to rank sort of what's what's really important in the night sky right let's say like you know Andy discovers a supernova in this galaxy but Tyler discovered that he really wants to see that galaxy how will we prioritize these resources that's it's a really important question and we kind of haven't figured it out yet it really kind of has this very complicated system of like who has telescope time who you know who has more power to like say like I'm going to use these fancy telescopes but this is a serious issue right because the thing is that the night sky is happening in real time so let's say like I think that I've discovered a really cool supernova and like I don't use like the most powerful telescopes to kind of investigate more about it and you know that's a big problem so astronomers are working on all sorts of algorithms that can tell us more confidently that like hey like this supernova is really important so like I need to follow it up and these are this is the information that I have so we use like these certain criteria to kind of tell us like yeah that's very urgent that's a great question yeah one of that what's my most controversial prediction about astronomy or opinion crap dang you got me unprepared well you know I put James Webb over here and I really think have you all seen the film Don't Look Up yeah that's what made me feel really uncomfortable because like it really highlights this point that you know if we make these really important discoveries in science right I feel that sometimes we can overlook at how important something is and so as James Webb has launched and will be collecting photons very soon I worry that James Webb is going to discover something so important but because of the way social media and people and politics works is that people are going to overlook on these discoveries so I think that's amazing that you all have come here to support science and really advocate for this work because it's really important that we really contemplate a lot about these things right it's really worthwhile yeah that's a great question any other questions why don't we go oh I love it the typical space versus okay so the question is what are the advantages we get if we would like to stay like we could put these observatories like on the ground versus like in space like you're like Andy like why don't we send this thing in space first of all that's a very big telescope and this is kind of a hard question if you do have like a billion dollars like definitely send it our way and like send it into space but the thing is that right it costs a lot of money another thing that you might not think about is let's say if something goes wrong then you're in trouble right because then you have to spend money to like send an astronaut to fix the telescope a lot of people don't know that when the Hubble Space Telescope launched there was an issue with one of the mirrors so we had to pay money for astronauts to go and fix that and so one of the main unique things is that if you keep your telescopes on the ground and we keep our night sky clean you know away from light pollution yes yeah that's very important we need to preserve the night sky right then ground based observatories have this amazing impact of being able to look at the night sky and you know if something goes wrong we can go to the telescopes and you know twist a couple of knobs to fix these telescopes and for them to continue to look at the night sky because our goal here is to look to just stare at the night sky to see all these changes happening the good question yeah one question here ooh so one is one discovery or innovation that I would like to see in astronomy in my lifetime well I really think that I would like to see the discovery well I guess like to kind of put at rest what this whole deal of dark matter is it's been really getting a strong I mean like yeah it's been going on for too long to just you know we really need to get to the bottom of this so and the amazing thing is that this observatory the very Rubin Observatory will you know the scale of this this experiment will really hopefully give us more answers about what is this dark matter you know like what is even the context of how the universe came to be so yeah I think that this telescope discovering the properties of dark matter and dark energy might tell us a lot about the universe good question last question we'll get the final last question yeah oh Sloan Digital Sky Survey my favorite SDSS well SDSS is kind of like the little brother this is kind of like what are we going to be doing with the Sloan Digital Sky Survey right the only thing is that we're going to be doing this on a much bigger scale right the Sloan Digital Sky Survey obviously there's different kind of programs that the Sloan Digital Sky Survey has been doing this another thing to keep in mind is that what the Sloan Digital Sky Survey is doing is that it's not looking at the light changing but the composition of objects change and that's the spectrum right so instead of looking at how bright things are which you know this was the whole point of this talk we'll be looking at the chemical composition and the chemical composition can tell us a lot of more interesting properties that's obviously not only the universe and just the brightness so in a way this telescope is going to be looking at the brightness and the reason why we use all these different kind of filters is to kind of understand maybe a little bit about the composition you don't have a lot of information because there's only you know there's a few filters that we use to kind of get that so you can't get you know the full composition of these objects but you kind of get an idea of what's maybe going on but yeah the Sloan Digital Sky Survey was an incredible survey and it's still going on alright thank you all again thank you so much everybody let's give a background and we'll be getting both of our speakers one final huge round of applause I don't know if anybody from Tesla is out here right now but they've probably been throwing me on a path for what maybe since years now since before I was here it's been so amazing having such a wonderful place to hold Astronomy on Path every month so let's give a big round of applause to Tesla and with that we will call for our first Astronomy on Path in two years our last bit kind of like ruling please keep an eye on our social media accounts for announcements about future Astronomy on Path we absolutely will be continuing to do this this is going to be a monthly thing going forward barring you know global emergencies but keep an eye on we'll let you know when the next one will be and where it will be and thank you so much for coming out here on this whole night