 Okay, hello again, everyone. Hello, I'm back. So we're going to get trivia started. Once again, if anybody did not get a trivia sheet, Sam has those trivia sheets. It seems like everybody has trivia, so we're going to get started. Right there, Sam. So tonight we have two really fantastic speakers. First, we're going to be hearing from Nick Wogan, who's going to be talking about asteroid impacts, atmospheric chemistry, and RNA, a story of how life might have begun. And our second speaker is Dr. Matt McQuinn from the Department of Astronomy at University of Washington, and he's going to be talking about how to find the most distant galaxy. And in honor of finding the most distant galaxy, we have some JWST-themed trivia for you tonight, which is also very timely because JWST is doing things now. So here's how trivia is going to work. I'm going to run through each of the trivia slides and leave them up for 30 seconds each. You write down all your answers, and it's great. And then at the end, I'm going to go back through all of the slides, but for a shorter amount of time, like 10 to 15 seconds each, we'll have you then turn in your trivia sheets to Sam once again, and we'll get started with the first talk while we grade the trivia. In between the talks, we will announce the winners of the trivia, and then after the second talk, if you win trivia, that is the time when you can come up and collect your prize. So everybody clear on the rules. Okay, cool. So I'm going to get started and go through the trivia slides 30 seconds a piece. Yeah, 30. 30. Point, I'm going to ask everybody to please send one person from your team to turn your trivia sheet and golf pencils into Sam right here. We need the golf pencils back. Let me emphasize that. And while you do that, I'm going to get the talk set up. Okay. Yeah. How many fingers up? Thank you. Thanks for getting your trivia sheets in. We're going to grade those and announce the winners in between the talks at this time. It's my pleasure to bring up our first speaker. Our first speaker of the night is UW Astrobiology student Nick Wogan. He works in David Katling's group in the Earth and Space Science Department, and he also collaborates with Dr. Victoria Meadows in the Department of Astronomy. So at this point Nick, would you like to take over please? So you can progress your slides. Oh, okay. Great. Yeah, okay. Okay. How's the volume in the back? It's good. Okay. So yeah, thank you for the introduction. Today I'm going to tell you a story for how life may have begun. This story involves asteroid impacts, atmospheric chemistry, and RNA. But before we get into that story, I need to give you some background on origin of life research. So here is a tree of life. You would have seen this in a high school biology class. At the bottom of the tree is the origin of life. And over a very long time, this first life evolved to become all the creatures we know today, like animals, and mushrooms, and plants, bacteria. But so all the creatures around us were all related. We all have a common ancestor. And that oldest common ancestor is the origin of life. So all this evolution, it took a very, very long time. So the origin of life happened between 3 and 1 half and 4 and 1 half billion years ago. And we know this because the Earth formed 4 and 1 half billion years ago. And also the oldest fossil ever found was 3 and 1 half billion years old. So life must have began between those two events. So for reference, the origin of animals was 750 million years ago. So the origin of life happened long before that. So since the origin of life happened so long ago, little information about it has been preserved over time. Geologists try to understand the origin of life by, is this turning on and off? Is it? OK, we're working now. Are the spots working? Yeah, yeah, we're going to move forward. So geologists, they try to understand the origin of life by looking at the chemistry of old rocks. But they have a really hard time doing this because there are not that many rocks that are as old as the origin of life. And biologists, they try to understand the origin of life by looking at molecules in cells, in modern cells. But this is really hard because life has changed and evolved so much. So since we don't have that much data on how life began, then scientists have come up with many different ideas for how it began. So there are no constraints on our imagination, and it's run wild. So those many ideas, they fall into two main categories. There are replicator first hypotheses, and there are metabolism first hypotheses for the origin of life. And replicator first hypotheses, scientists emphasize the importance of a genetic replicating molecule that evolved to become the first life. And in metabolism first hypotheses, scientists think that the first living thing was maybe a metabolism. So by metabolism, I mean, as an example, how we get energy when we eat food and when we breathe air. So I have witnessed quite a lot of controversy and argument between the scientists that work on these ideas. So it's sort of like Team Edward and Team Jacob in Twilight. These scientists really don't like each other at all. And so the story I'm going to tell you today is a replicator first hypothesis. So I'm clearly Team Edward. But so there are many scientists that will agree with what I tell you. And there are others that will think it is totally garbage. So in a nutshell, this is my story for the origin of life. So first, Earth formed. And then there were asteroid impacts that caused unique atmospheric chemistry. And that made special molecules flow into ponds of water, which led to the formation of RNA. And then RNA evolved to become the first life. I'm going to tell you the story backwards. We're going to start with the origin of life and the evolution of RNA. And we'll work our way backward to the beginning of the Earth. So first, the evolution of RNA. But before that, what is RNA? RNA is just a molecule. It is made of smaller molecules strung together called nucleotides. So there's four different types of nucleotides shown by this RNA cartoon, the different colors or different types of nucleotides. And you can string together the nucleotides in different orders. And that gets you different RNA molecules. So you may have heard of RNA recently because our COVID vaccines are made of RNA. And you may have also heard of RNA because it's kind of like DNA. It's kind of like our genetic code. So RNA does all sorts of important stuff in cells and in our body. The reason why the RNA is interesting in the origin of life is because RNA molecules can replicate and evolve by a process called base pairing. So here we have an RNA molecule. Let's imagine that it's in a pond of water and that there are lots of nucleotides floating around in that pond. There will be a tendency for those nucleotides to base pair with the RNA and make a mere copy of the original. The base pairing process can happen again and it will make a full copy of the original RNA. And every once in a while during this copying process there will be mistakes. There will be mutations. So this imperfect replication process, this is basically evolution. This is Darwin's evolution. And so the idea is in the origin of life is that these RNAs could evolve and become more and more complicated and eventually become the first cells. And this isn't something that is theoretical. This has been shown in the laboratory. People have put RNA molecules in test tubes and shown that they can evolve and become much and much more complicated. So another reason why RNA is interesting in the origin of life is because there are lots of molecules in cells that have RNA fossils at their core. So this is sort of a blast back to high school biology. So if you remember the ribosome. So here we have a cell. It's got a ribosome in it. It's also got DNA in it. Well, the ribosome is really important because it reads the DNA and it makes proteins. And then proteins do a bunch of important stuff and cells in our bodies. So ribosomes are fundamental to life. All life on earth has a ribosome. It turns out that the ribosome has an RNA molecule at its very core. It's what makes the ribosome work. And so people view this RNA as a fossil. They think that this RNA molecule was originally the ribosome and then over billions of years that ribosome evolved to its current state. So the summary of the past few slides is that perhaps RNA was the first lifelike molecule and it evolved to become the first life. But a problem with this story is that we have not explained the origin of RNA. We can't just assume RNA was around on the earth four billion years ago. Well chemists have thought a lot about how you can make RNA on the earth long ago. And they can get very, very close to making RNA with just hydrogen cyanide in a pond of water. So hydrogen cyanide is unfortunately best known for being a chemical weapon. But it is very important probably in the origin of life. So I would love to explain to you how hydrogen cyanide in a pond of water can make RNA. But honestly, I don't really understand it. When organic chemists try to explain to me how this works, they show me a diagram that looks like this. And I just give up. And so we're going to have to trust them that this generally works out pretty well. So this is great. We can have hydrogen cyanide in a pond of water on earth four billion years ago. It can make RNA. And then RNA can evolve to become life. But where would the hydrogen cyanide come from? We have to explain the source of hydrogen cyanide on the earth four billion years ago. Well researchers have thought a lot about this as well. And they think that maybe the most likely source of hydrogen cyanide would be chemistry in an atmosphere that contains methane. So this is the same methane that is in natural gas that heats our homes, lets us cook, all that. So we know that methane atmospheric chemistry makes hydrogen cyanide because we have observed it occur. And we have not observed it occur in our atmosphere because we don't have that much methane in our atmosphere. But there are lots of other planets and moons in our solar system. And it turns out that Saturn has a moon named Titan that has a atmosphere with a lot of methane in it. And we've sent spacecraft to Titan. And we've pointed telescopes at Titan. And we've worked out that that methane, plus some ultraviolet light, and a few other chemical reactions, make hydrogen cyanide. So this is great. We can have methane in the atmosphere on earth four billion years ago. And then that atmospheric chemistry can make hydrogen cyanide. The hydrogen cyanide can flow into a pond of water. And then RNA can form. And then life can begin. But we need to explain the source of methane as well. Where would the methane come from? Well, maybe the most likely source of a lot of methane would have been really massive asteroid impacts. So here I'm going to explain to you how big asteroid impacts could make methane. So on the left here, we have the earth four billion years ago. And we can imagine a very big asteroid colliding with earth. The energy from this asteroid would vaporize the entire ocean and make a steam atmosphere. So this impact or this asteroid, it would deliver iron to the surface of earth. This iron would react with steam and carbon. And it would produce methane and hydrogen as well. So eventually, the steam atmosphere would condense back to an ocean. And you'd have an atmosphere that contains methane. So this is all pretty complicated. And you don't really have to remember all of it. Just remember that large asteroid impacts could probably make methane. So it turns out that it requires a very big impactor, a very big asteroid, to create methane in the atmosphere. The impactor probably has to be bigger than 1,000 kilometers in diameter. So for reference, the impactor that killed the dinosaurs was 10 kilometers in diameter. And it's this little pebble down here. So we're talking about really big asteroid impacts. And we know that earth was hit by massive asteroid impacts because of the moon. There are craters on the moon. And 50 years ago, we sent astronauts there. And they picked up some rocks. And they took them home to earth. And scientists figured out that those craters are 4 billion years old. So there were asteroids that hit the earth 4 billion years ago. And we've used that data to figure out how many asteroids hit earth 4 billion years ago. And we've worked out that about two asteroids, bigger than 1,000 kilometers in diameter, hit earth then. So that is my story for the origin of life. First earth formed. And then there were asteroid impacts that made methane. The methane chemistry produced hydrogen cyanide. The hydrogen cyanide flowed into ponds of water, forming RNA. And then RNA evolved to become the first life. So at this point, you might be thinking, well, that's a really cool story. But is it true? And I would respond, that is a really good question. Because that is what I do for my research. I try to figure out whether this story is a good idea or a bad idea. So I work on the first part of this timeline. I work on the part involving asteroid impacts in atmospheric chemistry. So specifically, I simulate the atmosphere in a computer to estimate how much methane and hydrogen cyanide are made after massive asteroid impacts. So this research has two main steps. The first step is I write down some equations, so math and physics equations that describe how methane and hydrogen cyanide are made in the atmosphere. And then I take those equations, and I stick them in a computer, and I solve it. So here I'm going to show you a simulation of mine of the atmosphere after a 1,000 kilometer impact. So on this plot is time on the x-axis. And it's a logarithmic scale, so time is exponentially increasing, time is in years as well. On the y-axis is the abundance of gases in the atmosphere. So before the impact, I assume a CO2 nitrogen atmosphere. I assume this because this is what we think volcanoes, the gases that volcanoes would make, four billion years ago on Earth. So at time equals zero on this plot, there's a massive asteroid impact, 1,000 kilometers. It makes a hot steam atmosphere, and it also produces a lot of hydrogen. So then in this cooling steam atmosphere, methane forms. You'll see methane is the black line there. And then after 1,000 years, the steam condenses out of the atmosphere into an ocean. But the atmosphere continues to evolve, and the methane chemistry, it produces hydrogen cyanide. So you can see that the dashed line is hydrogen cyanide, and it's referenced to the right-hand axis. It's the surface concentration. So the maximum surface concentration in the simulation is 20 times, or 2 times 10 to the minus 11. So in English, people often call this 20 parts per trillion concentration. So if you had a trillion molecules at the surface of Earth, then 20 of them would be hydrogen cyanide. And this sounds like a very small concentration, but it's actually pretty big for hydrogen cyanide. So there's some other stuff happening here. Hydrogen is made when the impact happens, but eventually the hydrogen escapes to space. As hydrogen is light, it likes to escape, so it escapes. And when all of it escapes, it dramatically changes the chemistry of the atmosphere, and hydrogen cyanide stops being made. So I've done a lot of simulations like that, and we've come to a few conclusions. So the first conclusion is that asteroid impacts indeed do make methane in the atmosphere. But it takes a really big impactor. The impactor has to be bigger than about 1,000 kilometers in diameter. Smaller impactors just don't produce much methane at all. And so for these big impactors, then it turns out that our model says that hydrogen cyanide should be produced from the methane, and that this hydrogen cyanide should flow into lakes on the surface of Earth. But our model has also found that these lakes in the surface environment would be very hot. It would probably be about 200 Fahrenheit at these lakes. And this is potentially an issue for the formation of RNA because RNA is very fragile. So COVID vaccines, which are made of RNA, are stored at negative 80 Fahrenheit. And that's because if we stored them at room temperature, the RNA molecules in the vaccine would just fall apart. So this is potentially a problem, and we do not know at this moment if this is an issue for the origin of life. This is something that we are working on. So there's a tempting extrapolation of these results. I told you before that the moon craters say that Earth was struck by about two impactors, bigger than 1,000 kilometers in diameter. If an impactor bigger than 1,000 kilometers in diameter is required to make enough hydrogen cyanide for an origin of life, then maybe the origin of life on Earth had only two opportunities for success. So maybe life had just a few rolls of the dice in the beginning. But of course, I have to be a good scientist and say that these results have uncertainties and it's too early to make this sort of extrapolation with confidence, so yeah. So I recognize that this is astronomy on tap and I haven't talked a lot about astronomy. We've talked about biology, chemistry, stuff like that. So I wanna make up for that right now. So a lot of you probably know about the James Webb Space Telescope launched eight months ago, it's the most capable space telescope that's ever existed. And one of the main goals of James Webb is to search for life on planets in other solar systems. And the success of James Webb in that search really depends on the likelihood of the origin of life. If the origin of life is a very improbable thing and it was very lucky that it happened on Earth, then maybe James Webb won't find life on other planets. But if origin of life was really easy on Earth, then maybe James Webb has a better shot at finding aliens. So the origin of life is intertwined with these big missions, astronomy missions like James Webb. So that is all I have for you. Thank you very much for listening to the story for the origin of life. See here, I will just like you handle it. Okay, great. Oh, go ahead. That's a great question. So, oh yeah, the question was why does the impactor need to be 1,000 kilometers in diameter or bigger to make methane? The answer is because bigger impactors deliver more iron. And iron is really important for changing the chemistry of the atmosphere. Smaller impactors deliver much less iron. And so it changes the chemistry of the atmosphere less. Yep. Is there an opera? Yes, there is. We know that there's an upper limit to what impactor would have hit the Earth. It wouldn't have been bigger than the Moon, for example. We know that much. And that's just based on the craters on the Moon. It's very, very unlikely that that happened. So that would be the upper limit. Yeah, so I don't ascribe to it necessarily. Well, I like to be a good scientist. I like to be a good scientist and say that I'm just exploring this idea and I want to figure out if it's right or wrong and I don't necessarily ascribe to it. But the reality is that there is a lot of more experimental evidence for RNA or for replicator-first hypotheses than for metabolism-first hypotheses. But so it does push me in the direction of a replicator-first hypothesis. Yeah, that's a good question. So I talked about all these asteroid impacts. All these would have happened, whoa. So how did the Moon form them? Almost certainly the Moon formed by an impact, a very, very massive impact. Something about the size of Mars hit Earth right when Earth was forming, like 4.5 billion years ago. And then it just stuck around. And so then the Moon was the thing and it was circling Earth. And then after that, there were a bunch of impacts. So that's what I'm talking about are all the impacts that happened after the Moon. But it's a little bit, it's separated by about 500 million years or so in time. So let's go way to the back. So the question was, what is my feelings on Pangea, right? The idea that life began on Earth or it came to Earth from another, delivered by an asteroid, right? I think that's, that definitely could have happened. But it doesn't solve the problem of how life began. It began somewhere and that's a puzzle. There was some chemistry that led to the origin of life, some environmental conditions. And so that is something worth finding out whether it happened on Earth or Mars or even somewhere else. Yeah, go for it. Yeah, so the question was, does this have anything to do with the Goldilocks zone? Yes, it does. So if Earth was not in the Goldilocks zone when all this went down, then it would have been super hot, like 2,000 Kelvin or maybe very, very hot, like an oven. Or it would have been very, very cold, like Mars potentially. And so you've got to be in the Goldilocks zone for this to work out very well. Okay, just one more, we'll go. Yeah, wait, what was the second question again? Okay, it's the simulated conditions. And then you were asking about the iron. It's not a delta, it's not like there was some amount of iron on Earth and then the impactor delivered more. It's that that impactor delivered so much at that moment. So I hope that answers it. But yeah, I think that's what we have time for. I'm gonna hand it back to Megan, but thank you guys so much. I feel not the best. Yeah. Do you want to switch over to the trivia slides on our PPA? In the thingy. One second. Can I have the slide, advanced sir? Thank you. Okay, let's give one more hand to our speaker, Niff. That was fantastic. So at this point, what I want to do is go through the trivia answers and then I will announce the trivia winners. Tonight we have three winners that are getting prizes and about a million people who are getting honorable mentions. Normally I would give these people prizes as well, but you can blame each other because we don't have enough for. So the one big winner, the big winner, the one true winner to rule them all got eight answers, right? And the other two people that are getting prizes got seven right, the rest got six. Okay. So without further ado, first one, Jimmy Buffett recently toured the JWST control room. Yep. There has not been a Lego model company release kit for building the JWST, but that would be a really good idea, right? Yeah. Okay. JWST will not be observing the cosmic microwave background radiation. JWST's primary mirror is approximately the height of a giraffe. Neither of these images show the Southern Regnabula in visible light. I am not sure. I did not write these questions. Total. Total. Okay. The JWST's mirrors are gold because it's the most reflective material for the light that is observed by the James Webb. James Webb was originally supposed to launch in 2007. Yeah, that's pretty comical. I guess point C is the distance of James Webb from the Earth. This deep field image was taken in 12.5 hours. And finally, although JWST launched less than one year ago, astronomers are already planning its successor to be the large UV optical IR surveyor, also known as Lvoir, also known as Lubex, also known as Havoir. All right. So I'm going to announce the winners. I bet you all wanna know. But for these winners, only come up to get your prize after the second talk. Okay. After the second talk. So I'm gonna start with the honorable mentions. First up is Blue Aliens. Yeah, good job. Thank you. The next one is Maddie. Mr. Euros. Seven things, seven rings. I got it. Team Soul, the Rooks. We're getting less enthusiastic with each honorable mentions. Gone Plad. And finally, the last honorable mention is Skycar. Okay. So now for the winners. The first, the seven answer winner is DPMN. Nice. Well done. The next seven answer winner is Dan. Well done. And then the eight answer winner of all time is not that Sam. Okay, so now give me 30 seconds to go figure out the talk situation. Oh, you need to go get more beer? Oh, okay, okay, okay, okay, okay. Actually, we're gonna do like a five to 10 minute intermission in case anybody wants to go get more beer. Okay. Is there anything in particular you want me to say in your intro? No, yeah, you don't have to say anything. Welcome back. I hope everybody is sufficiently inebriated. How's it going? How's everybody doing? Good. All right. Okay, so at this point it is my pleasure to introduce our last speaker of the evening. I'm about to bring on Dr. Matt McQuinn, who is a professor in the Department of Astronomy at the University of Washington. He studies cosmology. Right in accentuation. Yes. He studies cosmology and he also, I have taken his classes before. And he's a really good professor. So without much more of this, I'm gonna bring up Dr. Matt McQuinn to talk about how to find the most distant galaxy. Thank you so much. Yeah, okay, so we're gonna be talking about way more distant things. Oh, is that okay? So there's a problem with that, which is that I flail my hands to explain things. So, but we can also go to the stand if we need, but I will try my best. So, okay, okay. So you guys are already way more knowledgeable than I realized in that I was gonna tell you what James Webb was and it launched. And you guys answered like a zillion questions. You even answered how many hours this image was observed for. I learned from your trivia question. Yeah, okay, so this summer has been amazing in terms of this telescope. It was launched in December and data started coming out this summer and the data is amazing. And if you're a scientist like every day someone is announcing the most distant galaxy and so I'm going to talk to you about what is happening in the astronomy community. And even if you're not a scientist, you're probably reading like science journalism is just reading all of these things about the most distant galaxy discovered and the next day the most distant galaxy discovered. And so that's what this is about. This talk is about how the heck do you find the most distant galaxy? What does it mean? And there's a bunch of elements that go into this and so you will see. Okay, but we're going to start with something simple which is that there is, you guys are all familiar with waves. Waves are ubiquitous. I am talking to you with sound waves, which are like centimeter to few meter waves that your ear is registering. Waves occur everywhere. And for example, if you drop a pebble in water then waves emanate out. And what's going to be very important for this talk is the wavelength of things. So the wavelength is kind of the scale over which there are structures. So the wavelength is like this here, like the between the different peaks. So waves you often talk about in terms of wavelengths. And so the sound waves have some wavelength. These are gravity waves. And water has some wavelength. And then light also has some wavelength. And so light is kind of unique in that it actually can travel in a vacuum. It doesn't have to be anything around. Here I need water for sound. I need air. For light, it can just travel in the vacuum of space and what it is is you have some electric field just like what, you know, electrons to flow in your outlets so you give you electricity. And so light is just electric field that takes charged particles and moves them up or down. And the scale that it moves them up or down is the wavelength of the light. And so like it comes into your eye and it moves the molecules and the rods in the rods and codes in your eyes distorts them and you detect it. It's kind of amazing. And the light that our eyes are able to see are kind of like a millionth of a meter, maybe a little bit shorter than that. So we're able to see a millionth of a meter light. James Webb Telescope is able to see infrared light. So it's a little bit longer than that in wavelength. Okay. So we can think of light in terms of wavelengths and so we're going to start off with the sun. And so this is the sun. I can put it through a prism so I can have like a little pinhole and all of the light from the sun can go through that pinhole. Then it goes through a prism and the prism, as you guys are probably pretty familiar, can break it up into different wavelengths. And then I can calculate how much light I have in different wavelengths and that's what we call a spectrum. And so this is just a tabulation of I have this amount of light over here. This is actually the ultraviolet. And then I have this amount of light here. This is blue light. This is red light. And then this is the infrared light from the sun. So this is the spectrum of the sun. All of these features are because there are atoms in the sun that have characteristic energies that they like to radiate in. And so you get all of these kind of features but this is what the spectrum of the sun looks like. Okay. And you can do this for other stars. So the sun is kind of a somewhat overweight star. Like it's a little bit bigger than the average star. And so like if you take a smaller star than the sun and you take its light, you put it through a prism, then a smaller star than the sun will have a spectrum that's a little bit redder than the sun. So this is the spectrum of the sun. This is some weird astronomical naming that you don't have to be familiar with. But this is just the amount of light and these are spectra. So this is the wavelength of the light. This is the spectrum of the sun that we were just seeing. And if you take a smaller star than the sun, it's the light that comes from it is a little bit redder. And if you take a bigger star than the sun, the light is a little bit bluer. So this would be a bigger star. So if you put this light through the prism, calculate how much light I get at different wavelengths and I have a bluer spectrum. So bluer is over here. So I have more light here than over here. Redder, I have more light on the right-hand side of this diagram. OK. Other thing to note, big stars are very, they like to gobble up, or they like to use their fuel very quickly. And so they output a lot of energy in a short amount of time. They only last millions of years. Their lifetime is only millions of years and then they explode. That's like supernova. So this is important. So if your galaxy has big stars, then it emits a lot of blue light. But if you wait a little bit, all of those big stars go away. OK. So we were talking about stars. This is a talk about distant galaxies. Why am I talking about stars? Well, as you are well aware of, a galaxy is made out of lots of stars. Actually, how many stars in a galaxy? What about this galaxy? Does anyone know what galaxy this is? Yeah, this is Milky Way's twin. It's very similar in mass to the Milky Way in terms of stars. How many stars would you say it has in it? You guys are great. I hear a billion is good. It's about 100 billion stars in these galaxies. But I've heard more significant figures than I know. So some of you may know this better than me. But yeah, it's a big galaxy like this has 100 billion stars. OK. So we can do the same thing with stars, with galaxies. So a galaxy is just made out of a bunch of stars. So I can now just take the light from a galaxy. This is actually two galaxies that are merging. You can see that there's a lot of blue light here. These are the big stars. So it's forming stars. I put it through a prism. And then I look at the amount of light as a function of wavelength and it's bluer. And that's because I'm seeing these bigger stars. So it has bigger stars with forming stars. I also see a bunch of lines that are from gas between stars. And we're going to come back to these lines later. But the amount of light under these lines, so you can see all these peaks, these are the lines, part of that is telling me about what stars the galaxy has. OK. And instead of pointing this out in the beginning, we were looking at that image. In fact, we're going to go back. And there are a few things I didn't say. So one thing is this is a tenth the width of the moon on the sky. So the width of the moon is my thumb at arm length. So the width of this image is a tenth of that. And if you look at this image, there's a few stars in it. You can tell these are stars in our galaxy. The things that have spikes are stars in our galaxy. Every other light source in this image is actually a distant galaxy. And so you can see that there are some galaxies that are bluer and some are redder. So there's this diversity of galaxies. And the one thing that we're going to eventually get to is there are these little red specks in this image. And those are the distant galaxies. So we're going to search for those because we want to find the most distant galaxy. OK. All right. So this is a galaxy that's forming stars. It's bluer. This is a galaxy that's not forming stars. It's redder. These actually tend to be the biggest galaxies in the universe. These are the big balls of stars. You put it through a prism. You look at it spectrum. It looks a lot more like the sun spectrum. Like if we go back where there's a lot of going back, it looks a lot more like this one where the other galaxy that's bluer looks more like this. OK. And this is just because galaxies are just a bunch of stars. The light that we're getting from the galaxies is just that we're adding up stars of different masses. But if you have big stars, they emit a lot more light than small stars. And so they dominate. In this galaxy, the big stars are dominating. It's more light in the blue. OK. So if I look at a galaxy, and I measure how much light I get, how much blue light, how much red light, it tells me what type of stars the galaxy has. It also tells me the mass in stars. OK. So there's a lot of chapters. This is like a novel. OK. But this chapter is super cool. Sorry, I heard something. OK. Yeah, OK. OK. So about 100 years ago, a little less, 1929, we realized that the universe is expanding. Actually, not long before this, we realized that there were other galaxies in the universe. Like a lot has happened in the last 100 years. And the way we realized that the universe is expanding is this plot. This is the Hubble diagram, Edwin Hubble, the same Hubble that the Hubble Space Telescope is named after. And what it shows is every point here is a galaxy. And this axis, the x-axis is distance. The y-axis is velocity. And so every point is a galaxy. This right here, this is 3 million light years. So 3 million light years. If I go to this galaxy, it's 3 million light years away. It's moving 500 kilometers per second away from us. 500 kilometers per second. We're going around the sun at 25 kilometers per second. So it's a lot faster than you drive. But we're going to be talking about things that move very fast. And then this is 3 million light years. 6 million light years is over here. 1,000 kilometers per second. And so Hubble realized that he could draw a line. And that galaxies, this is very brave of him at the time, but that galaxies kind of fall on this line. The further away they are, the faster they're moving. This is the modern version of this. The modern version of this is amazing. The axes are flipped, unfortunately. This is velocity. And it's velocity and use of the speed of light. The speed of light is 300,000 kilometers per second. If you know more than what I'm saying, then some things I'm saying are not exactly right. And then this is distance. So this is the distance of the galaxy. Remember, 2 million light years, it's off the bottom of this pot, like what we were just talking about. This is 100 million light years, 1,000 million light years, 10,000 million light years. And these are different galaxies, and so as I go further distances, they're going faster and faster away. So if I'm able to measure the velocity of something, I'm able to translate that to a distance. I know the velocity, I can go to distance. Okay, next thing. We're back to waves. Okay, so you guys are very familiar with this effect. Amulet zooms by you, and when it's coming towards you, it's pitch sounds a little bit higher than when it travels, when it's moving away from you. And the reason for this is the amulets is emanating sound waves, like woo, woo, woo. And the sound waves, when it's coming towards you, they're kind of crunched together. So the wavelength is a little bit shorter, which means that I hear it as a higher pitch. Like if the ambulance is going 70 kilometers per hour, the speed of sound is, oh sorry, 70 miles per hour, and the speed of sound is 700 miles per hour. So this is like a 10% effect, actually. The waves are 10% shorter when it's coming towards you. Then when it's going away from you, it's the opposite. They're 10% longer. Okay, the same thing happens for a galaxy, but now it's, rather than speed of sound, it's speed of light. Like if it's going very close to the speed of light, this has a huge effect on the wavelengths that we see. So I just told you that the galaxies are moving away from us. Almost all galaxies are moving away from us. The further away, the faster they're moving. And so as they're moving faster away from us, this stretches the light. So we see longer wavelengths from galaxies that are moving faster away from us. Galaxies that are moving faster away from us are more distant. So here's my animation of this. This galaxy is moving faster than that galaxy. And so the wavelengths, which are the different contours here, are longer. And then if it's going really, really fast, then this is very sophisticated. Then it looks like this. And so we're going to get to this, but some people are claiming that some of the galaxies that they find in JVDC are moving so fast that their wavelengths are stretched by a factor of 15. Actually, that's not, this isn't even old. I believe maybe the factor of 15. Some people are even claiming factor of 20. So we're seeing things that are moving so fast away from us that the wavelengths are so stretched. Okay. And then, okay. So this is the same plot I showed before. So before I called it velocity in units of the speed of light, but now I'm using a much more technical term, stretch factor, which I have made up. I'm not sure this term is going to catch on, but there's a lot of stretch factors in this talk. Okay, so the stretch factor minus one is the factor by which the light has been stretched. So if I go to one here, then that means stretch factor is two. And so the wavelengths of these galaxies are stretched by a factor of two. And then I can just go, if I measure the stretch factor, if I can measure how much of the wavelengths have been stretched, I can just go to this and I can say, oh, that galaxy is at 3,000 million light years. So I know the distance. So this is how we're going to figure out the distance to galaxies. This is how they figure out the distance. Not only that, but, okay, so another kind of interesting, maybe like, another fact is that if a galaxy is at thousands of millions of light years away, it takes a long time for the light to travel to us. And so we can actually calculate how long it took that light to travel to us. And so we can relate that since we know that the age of the universe is 13.8 billion years, we can relate the distance immediately to the time that the light was emitted since the Big Bang. So the universe is 13.8 billion years old. I subtract off how long it takes the light to travel from some distance. And I find that the universe, if I measure a stretch factor of 10, the universe is 500 million years old. If I measure when that light was emitted, if I measure a stretch factor of 20, it's even less than that. And that's what we're talking about. For the galaxies that James Webb is finding, they're like a few hundred million years after the Big Bang. Way, way before today, which is 13.8. Okay. Okay. Next, I told you this is a novel. I think this is the final chapter before everything happens. Okay. So there's one other effect that you actually have to understand in order to kind of comprehend some of these results that James Webb is reporting, which is that if something emits light, you are not guaranteed to see for that light to reach you. And you're very familiar with this. So the sun emits light, but when it's closer to the horizon, its light is going more through the atmosphere. So before at sunset or sunrise, when you look at the sun, it is redder than when it's overhead. And that's because its light is traveling through more of the atmosphere, and the atmosphere likes to scatter blue light relative to red light. And scatter means it just, it'll hit, the light will hit, the blue light will hit molecules in the atmosphere and just fly off in every direction. And this is just because the blue light is closer to kind of the frequencies that molecules like to scatter. Kind of there's some wavelengths that molecules like to scatter. In fact, ultraviolet light is even closer, which is really good for us because ultraviolet light doesn't make it to us or a lot of ultraviolet light. The atmosphere just blocks it for us. But okay, so the blue light doesn't make it to us as much as red light. And in fact, the scattered blue light we're very familiar with, right? This is why the sky is blue. So you look away from the sun, the sky is blue is because it's scattering the blue light relative to the red light. Okay, so it turns out that our atmosphere nitrogen, oxygen, these molecules, most of the universe is hydrogen. So 90% of the gas of the universe is hydrogen because hydrogen was produced in the Big Bang, or the Big Bang mostly produced hydrogen. It produced some helium. And so okay, so the analogy here is that the light from these galaxies, it has to go through all this hydrogen to get to us. And hydrogen likes to scatter light as it gets close to a wavelength of 122 billionths of a meter. And so if light ever gets near this, there's so much hydrogen in the universe it just scatters it and you just can't see the light. And so what happens, unfortunately this diagram is terrible, but this is the best thing I could find. I have my galaxy and it emits a bunch of colors of light. But the light that that galaxy emits, it's never the light that's shorter wavelength than 122 nanometers never makes it to you. But then because the galaxy's moving so fast away from us, its light is stretched. And so this light that the galaxy emits appears way over here in the infrared, and this is the amount of light from the galaxy. The amount of light, I don't get anything in the visible and that's because of this cutoff from the hydrogen scattering everything. It's scattered all of this light and I only get this light in the infrared. And in fact, this is why the long, long time ago they decided to build the James Webb Space Telescope is because they knew that if they looked at galaxies far enough away you would have to look in the infrared because the hydrogen would scatter everything else. And this and not astrobiome was the primary reason they decided to fund JWC long ago and then later on they realized planetary science is also interesting but this was the original reason that you have to look in the infrared. All of the other light from the galaxy doesn't make it to you. Okay. Okay you guys. So this is data that actually that was released in the last couple this is a paper that came out a couple, like in the last one. This is looking at that image that we looked at in the very beginning but really zooming in at some part of that image. And the, okay so what you see here are different wavelengths of light. And so this is less infrared closer to the visible still infrared. And as you go to this side it's more infrared light. And in fact if you look at this so again this is the amount of light this is our spectrum. Each of these panels corresponds to one of these purple measurements. So each of these is one of these purple measurements. And okay so you can see a bunch of things first of all these are just some like foreground galaxies. What we're really interested in is right here. So this is the purported very distant galaxy perhaps the most distant galaxy ever discovered. And so you can see there's no light here. No light here. No light here. And then it pops out. Something appears. This is exactly what you expect if the hydrogen has made it so the light never made it to you if it was scattered. And so this is the, you then can just calculate how much light I have in each of these images and you get these purple points. And then the next stage of this and this is why we had to go through many steps is that you then need to, you have to convince yourself that this is the highest range of galaxy and not something else. And so this is a model for what a spectrum of a high range of galaxy looks like the orange curve. And this is the cutoff from hydrogen absorption, or hydrogen scattering. And the thing that is the hardest to distinguish is these red galaxies, old stars. So galaxies with old stars that aren't as far away. And so they're hoping that they can distinguish that which is this kind of very hard to see gray from the orange. And the claim is that they can, that's what this shows, that doesn't matter. And so this to me looks, for this galaxy it looks relatively convincing that they're discovering a galaxy with stretching factor of 12.4. This means that it's, a few hundred million years after the Big Bang, higher redshift than any galaxy discovered with other telescopes. But there is a problem. And the problem is that there are just so many of these galaxies that observers, people who do this for a living have been claiming in the last month, so many galaxies that it's hard for us to explain them. And so there are two solutions to this problem. So they've taken this James Webb image, they've found too many galaxies. And when I say too many galaxies, it's actually someone like me who tells them how many galaxies they should see. But they're finding way, way, way more than that. So there are two possibilities. One is we just don't know what the heck is going on and our model for galaxy formation is terrible. This in fact is not even galaxy formation, it's cosmology. And cosmology I would say is just so solid. But you can argue with me. And then the other is that maybe we just don't understand the spectrum of galaxies well enough and that this other possibility that you could have old stars and I didn't mention dust, but dust also does the same thing. Dust is just like things that absorb blue light. We just don't understand the spectrum of galaxies well enough and so there's a problem with this whole routine that we've gone through. But there's a way forward and this is my last slide I believe. And the way forward is that it comes back to these lines that I said are from gas that it's gas that's illuminated by big stars. So this is the galaxy spectrum we looked at at the beginning and you have these lines and if you measure, if you find any of these lines especially if you find a couple of them where some of them have weird shapes that you know exactly what element it came from. And so if you find any of these you know exactly what the stretch factor is. If you know the stretch factor you know what the distance and the cosmic time. So if we're able to find these lines then we'll know if these galaxies that we're finding are real galaxies. And the way you find these lines is if we go back to this plot you can see that the wavelength buckets like these points there are only a few points and we have big buckets. And it's because these galaxies are so far away that it's hard to break up the light into finer buckets and actually detect the galaxy. But James Webb has only been launched recently it's only been taking data in the last couple of months and so we have a lot of time potentially and so once we start staring longer we're going to be able to break up these spectra smaller buckets and we'll start detecting these lines and once we detect these lines we'll know if these galaxies are real. Thank you. I'm happy to take questions. Yeah. Oh yeah that's a wonderful question. So the question is that I told you that as the light travels or because of the velocity of the galaxies the energy is or sorry because of the velocity of the galaxies you observe a different wavelength of light than was emitted so the wavelength of light is actually inversely proportional to the energy of the light of the photons and so the different wavelengths also means different energy and okay so there are two answers to this question one is I didn't tell you exactly what was happening and I'm going to tell you this question I'll tell you a little bit more but first of all if it were that the galaxy were moving at a velocity that's very fast away from us then it's actually it's a bit more complicated in that the the the so things can in different if you're moving at different velocities energies can look different the that's not super satisfying this has to do with Einstein's theory of special relativity that's my first answer but the better answer is actually it's actually not the velocity when I say it's the velocity of things moving away from us it's a this is a little bit like not great and it's actually the so the universe is expanding and the expansion of the universe makes it look like things are moving very quickly away from us but you can't really say it's the velocity of the object related to us and so then when the object emits its light and it travels to us it actually causes the universe and this is true for all of the light in the universe it causes the universe to expand slightly less quickly because the light also has gravity and so this is and so the energy is actually going into the the gravity of the universe the so and there's a lot of different answers to the but that's a so that's the maybe that's the better answer yeah stretchy factor how does that relate to the speed of light in both parts stretchy factor how does that relate to speed of light can a galaxy be moving away faster than the speed of light general discussion yeah okay this gets a very similar issues that so if something is moving by me I can say it's moving at close to the speed of light things can never go faster than the speed of light if something went faster than the speed of light it would violate causality it would mean that you can things like you could go back in time and kill your grandma things if someone ever tells you that something went faster than the speed of light they are they better I would never believe it there was a neutrino thing that neutrinos go faster than the speed of light like 10 years ago and no one believed it other than it was reported by New York Times and everything but it was just crazy it's just really how we understand physics you can't really have things go at the speed of light and that said you can't have it so that because that galaxy is not next to me it's not really moving by me at the speed of light and so you can have it so that the space between me and the galaxy is such that it looks like it's moving faster than the speed of light it could even move so fast away from me that I can no longer see it at some point it could go move so fast that eventually its light can never make it to me that's what we think dark energy is doing we think that in the future all galaxies except the ones that are bound to us which is like andromeda we will not be able to see if we understand dark energy they will eventually move so fast away from us and so like move so far away that their light can no longer make it to us now that doesn't mean that they are ever moving at the speed of light it's just that it's some different place and the space between us has made it their light can no longer make it to us but these are really good questions and yeah I don't think I fully addressed your questions but that's okay yeah yeah okay this is really good so the question is is this just catchy science like if I you know I found the most distant galaxy but so what so the I think it's more than that maybe finding the most distant galaxy is a little bit in that the purview of the clickbait but so there are times in the history of the universe that we have not been able to observe much like we can see tons of galaxies around us we've done that really well we can even see when the universe was 400,000 years old because we can see the light from the cosmic microwave background not with James Webb but the from that time it turns out that the times where we have the fewest observations are when it's between 400,000 years and several hundred million years and also of course when it's less than a second there's also problems there we actually have observations of the universe when it's a second because that's what produced the hydrogen and the helium that we see in the universe but okay the so if anything it's quite possible that at this these times that James Webb is targeting that we just have things wrong for certain things things seem too wrong to me with what people are reporting some surprises can happen there the galaxies that we think are forming there are like little itty-bitty galaxies that eventually grow into our galaxy the universe at that time when the first galaxies are forming it's just hydrogen and helium all of the elements that are heavier than that haven't been all of the elements that are heavier than that haven't been those are synthesized in stars and so it's this time where you're kind of and we also think that when the first stars form just out of hydrogen and helium they're a lot bigger and so there are a lot of things that we don't know we don't know when the first stars form we don't know exactly what the first galaxies look like we don't know exactly when that happens and it fits into this cosmic picture even the like cosmic story and so I think there is a lot of good scientific motivation for even though maybe I don't care if it's exactly oh that galaxies a little bit further away than this galaxy I don't totally care about that but like the demographics of galaxy is at this time is very interesting yeah but I think it's again the it's the same that you can although it's the it's really the like velocity is a little bit tricky and so it's maybe it's easier for me to say I can tell you exactly how far away it is and I also know how things are expanding so in a sense yes you can now you can't see the galaxy the today you only you only see it at one point in time like when when it's at the distance that it's light can travel to you but it's it's there I there's no reason it has disappeared okay final question over there okay we'll do one more because you've done a question yeah yeah okay so there's a question of that if if you were on that the distant galaxy could you see the see something like us and and talk about us and the answer is that okay so the that galaxy eventually will become of a big a bigger galaxy and then it will see and then the light is traveling almost 14 billion years so it will see us 14 billion years in the past yeah we see yeah that's right it's totally symmetric and so if the there's life on the galaxy which is very likely because there's so many damn Tars and so like 100 billion stars almost every planet has a star I have to probably every galaxy has has life probably has intelligent life so probably it is the case that if that is a galaxy it is observing what is the progenitor of the Milky Way which is a bunch of little galaxies the if you know once they have their James Webb hopefully launched like on time there the they could they would be seeing exactly the same thing yeah okay final question back there actually how we've been able to like track the same galaxy to measure it a lot to have the other um yeah the so the question is are we able to watch the galaxies redshift with time the and redshift is the same as stretch factor which is the better term the yeah the so the answer is that the um this is actually uh because you probably have heard this person's name the about aliens the effect that you're referring to is called the sandage lobe effect the and the lobe is uh is synonymous with alien theories the and so the so it's a it's a really hard effect to see it's because so the age of the universe is 10 billion years and so the if we wait a year we expect the stretchy factor to change by uh 1 in 10 billion so if you wait 10 years it changes you know 10 times that but uh this is really hard to see and it's because the the widths of all of the features in the spectra are just way too big and so we don't have really good ideas except waiting very very long times for for actually being able to see this but it is an effect that um that might be like a future cosmology um the like on a long time scale something that we can do and observing this tells you about the constituents in the universe and oh actually one thing I didn't say is that this diagram is really interesting the in that the okay so this is was telling us what the stretch factor is as the function of distance but the different curves here are for different things in the universe so different things in the universe cause it to expand in different ways and the this is actually the the curve that goes through all of these is the universe that has dark energy it's at this is actually how we know the universe has dark energy but if you also observe how the redshift changes with time this this sandwich lobe effect it also tells you about the things in the universe which is one of if you're a cosmologist this is something you're really interested in but yeah this is this is a famous plot like noble prizes have been awarded because it tells it tells us exactly like these different curves are just different models for what is in the universe and it turns out that there's really weird stuff in our universe that's causing it to expand in a way that in the future we think we won't be able to see other galaxies and we won't so that we're at a very special time where we can see the these galaxies across the universe and we think that actually it's not going to be the case in hundreds of billions of years very sadly alright thank you let's hear another round of applause for both of our speakers with that our next out show on tap will be on September 28th and if you are one of our three prize winners please come see Sam to get your prizes everybody get home safe and have a wonderful night