# JWST’s 3 BIG mysteries of the early Universe ## Метаданные - **Канал:** Dr. Becky - **YouTube:** https://www.youtube.com/watch?v=Qu15C28QW8c - **Дата:** 29.05.2025 - **Длительность:** 14:40 - **Просмотры:** 197,099 ## Описание AD - Go to https://ground.news/drbecky to stay fully informed with the latest Space and Science news. Save 40% off the Vantage plan through my link for unlimited access | The cutting edge of science is where all the unknowns are. Where there’s more questions than answers, and it’s all hands on deck to try and understand our observations, experiments and data. And in astrophysics, that has never been truer after the launch of the James Webb Space Telescope - a telescope that could see galaxies at greater distances than ever before, allowing us to see galaxies as they were when the universe was just a few hundred million years old because of how long its taken the light to travel to us. And over the past 4 years, JWST has been taking what we though we knew about the early universe and how galaxies evolved, and just throwing it all out the window. And in particular, there are now 3 big mysteries that have emerged, that we can’t yet explain - which is incredibly exciting, because in the push to understand them we’ll hopefully learn something new, maybe even some new physics and understand our universe better… Adams et al. (2024) - https://arxiv.org/pdf/2304.13721 Bouwens et al. (2015) - https://arxiv.org/pdf/1403.4295 Bruzual & Charlot (2003) - https://arxiv.org/pdf/astro-ph/0309134 D’Eugenio et al. (2024) - https://arxiv.org/pdf/2311.09908 Harikane et al. (2023) - https://arxiv.org/pdf/2208.01612 Killi et al. (2024) - https://arxiv.org/pdf/2312.03065 Kocevski et al. (2025) - https://arxiv.org/pdf/2404.03576 McLeod et al. (2024) - https://arxiv.org/pdf/2304.14469 Nakane et al. (2025) - https://arxiv.org/pdf/2503.11457 Pérez-González et al. (2024) - https://arxiv.org/pdf/2401.08782 Rusakov et al. (2025) - https://arxiv.org/pdf/2503.16595 Vogelsberger et al. (2020) - https://arxiv.org/pdf/1904.07238 Whitler et al. (2025) - https://arxiv.org/pdf/2501.00984 00:00 Introduction 03:16 The number of bright galaxies 06:58 The amount of heavy metals 10:55 The Little Red Dots Video filmed on a Sony ⍺7 IV Video edited by Martino Gasparrini: https://www.fiverr.com/mgs_editing --- 📚 My new book, "A Brief History of Black Holes", out NOW in hardback, paperback, e-book and audiobook (which I narrated myself!): http://lnk.to/DrBecky --- 👕 My new merch, including JWST designs, are available here (with worldwide shipping!): https://dr-becky.teemill.com/ --- 🎧 Royal Astronomical Society Podcast that I co-host: podfollow.com/supermassive --- 🔔 Don't forget to subscribe and click the little bell icon to be notified when I post a new video! --- 👩🏽‍💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford (Christ Church). I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars. http://drbecky.uk.com ## Содержание ### [0:00](https://www.youtube.com/watch?v=Qu15C28QW8c) Introduction The cutting edge of science is where all of the unknowns are, where there's more questions than answers, where it's all hands- on deck trying to understand our observations, our experiments, and our data. And in astrophysics, that has never been truer than after the launch of the James Web Space Telescope, a telescope that can see galaxies at greater distances than ever before, allowing us to see them as they were when the universe was just a few hundred million years old. because of how long it's taken the light to travel to us. And over the past four years, JD Brush T has just been taking everything that we thought we knew about the early universe and how galaxies evolved and just chucking them straight out of the window. And in particular, three big mysteries have emerged that we still can't explain, which is exciting because in the push to understand them, we'll hopefully learn something new about our universe, maybe even some new physics. So those three mysteries are first of all the number of bright galaxies in the early universe, second the amount of heavier elements in the early universe and three the little red dots. So in this video we're going to go through each of those mysteries and we're going to chat about what is the cutting edge for each one of them. So if you've come to this video for answers, you're in the wrong place cuz it's just going to be a whole bunch of questions. And I know it is very hard to stay up to date with what's going on with JBST in terms of the results coming from it just because there's so much misinformation and just made up stories that are flying around the internet. Take this story for example. Bright auroras on Jupiter are captured by web space telescope. If you see this online, how do you know that it's actually legit? Well, thanks to Ground News, the sponsor of this week's video that I've been working with for over a year now, I can immediately see that this is a news story covered by 41 different sources from around the world, and that 95% of those sources have a high factuality rating. So immediately, I know this is a real story and it's something that I can trust. Then with ground news, I can compare the different headlines from different news sources. So I can see that the Manchester Evening News went with NASA telescope captures auroras that glow hundreds of times brighter than the northern lights. Whereas Live Science went with James Webb telescope reveals impossible auroras on Jupiter that have astronomers scratching their heads. So it's great to have all of that in one place so that I can just, you know, immediately know what all the main points of the story are, but also I can see if some outlets might be over sensationalizing the story with clickbait headlines. The feature of theirs that I use the most is their blind spot feed because I also find it so interesting to see like which stories have little to no reporting on either side of the political spectrum just so that you can get a really well-rounded picture of what's going on. I've also heard from so many of you that you love Ground News for a whole host of reasons. So, I'm really pleased that they're continuing to support this channel. So, if you head to the link in the video description below, ground. news/dbecky news/dbecky or scan the QR code on the screen. You'll save 40% on their Vantage plan which gets you unlimited access to all their features. It comes out at around about $5 a month and those subscriptions keep Ground News ad free. So free of all of the biases that come with paid advertising. So a big thanks to Ground News again for sponsoring this video. And now let's dive in some of the mysteries of the early universe as revealed by JWST. And start first with ### [3:16](https://www.youtube.com/watch?v=Qu15C28QW8c&t=196s) The number of bright galaxies the number of bright galaxies in the early universe. So one of the most common and simplest things that we do to try and understand the universe out there is count things and count how many of each different type of things there are. So for galaxies what we do is we count how many of each brightness there are. So then we can understand how many faint galaxies there are and how many bright galaxies there are in the universe. Brightness correlates with how many stars are there in the galaxy and therefore how massive the galaxy is as well. So that when we plot this out and we see this spread of how many bright galaxies form and how many faint galaxies form, we can then understand the processes that form them and any simulations that we run of the universe with all the laws of physics thrown in then need to reproduce that spread that we see in the real universe. And if they don't, we then know that there's something missing in our simulations like some law of physics that we've forgotten. Now we call this spread of the amount of each brightness of galaxies the luminosity function. And what's fun is that we actually see this changing with time. Because light travels at the speed of light, just less than 300,000 km a second. It means that it takes time to travel to us. So as we see distant galaxies, we're seeing them as they were when the universe was much younger. So we can quite literally watch the universe evolving with time. And so as you get to greater distances, you can see the luminosity function change. average, so most common luminosity or mass for a galaxy is less. And that makes sense, right? Because galaxies form more stars over time. So they get more massive but they also get brighter over time as well. And so similarly you can see that there are less very bright galaxies i. e. the most massive galaxies as you get to earlier times in the universe's history as well. We've seen this with our observations using the Hubble Space Telescope and it's been a prediction of simulations as well. But over the past four years using JWST to observe the distant universe, there have been many research papers that have come out where they've been counting how many galaxies of each brightness has been spotted by JST at greater distances than ever seen before and there seems to be too many of the brightest galaxies found. Well over what we've seen with the Hubble Space Telescope and what's been predicted by simulations. These have been referred to as apparently over massive galaxies which you might have heard me talk about on this channel before or also as you know galaxies at the bright end of the luminosity function and explaining them is one of the big issues that many people who work with JD data are focusing on and now there's a lot of ideas floating around to try and explain them but there's still a lot more work to do to figure out which one is actually responsible if it's even just one solo thing it might be a collection of many things. So, for example, it could be that star formation is just way more efficient in the early universe than what we see around us today. Like, if you have a gas cloud, you can form stars quicker and maybe even more stars from it than what we're used to. Or maybe if you do form stars from a gas cloud, you form a different spread. Again, if we count the number of stars that you form, like massive stars and smaller stars in the Milky Way, you get this expected spread. Maybe in the early universe, you form a lot more of the more massive, heavier stars from a gas cloud than you do smaller stars, which would make the galaxy brighter, but not necessarily heavier. Or maybe there's light from material that is spiraling around a growing super massive black hole that's got so hot that it glows. And maybe we've not taken that into account and maybe that accounts for some of the light here. Or maybe there's something else that we've just missed in our theories of how galaxies form. Maybe some new physics that we've yet to learn about. That perhaps ties into number two on my list of these big mysteries. The ### [6:58](https://www.youtube.com/watch?v=Qu15C28QW8c&t=418s) The amount of heavy metals amount of heavier elements in the early universe. Because in the really early days of the universe, the first elements ever formed were just the simplest ones with around 75% of the universe being hydrogen and just less than 25% being helium and then you got just trace amounts of like lithium and heavy hydrogen. It was only then when stars formed that they actually were able to make the heavier elements in the nuclear fusion process. So carbon, oxygen, nitrogen, and all the way up to iron. Then when a star ran out of fuel and died in a supernova, those elements would then get dispersed across space, essentially enriching the universe with the trace amounts of those elements that the star would produce. But that process takes time with the lighter elements turning up first and then the heavier elements later. And you need many generations of stars to produce enough of these trace amounts of heavy elements that you get from the stars lifetime to have built up enough in the sort of like gas between stars and in stars themselves when they form for us to then actually be able to spot the fact that these heavy elements are there. We can spot them thanks to the impact they have on the light that passes through stars atmospheres. They steal away certain colors of light that are unique to each element. So, we know that they're there. Or if those heavy elements are present in a gas cloud between stars and the stars are shining energy onto that gas cloud through light, then the atoms can actually steal some of that energy and then reraiate it at very specific wavelengths of light. So instead of a gap in the you know rainbow of light that you get this big bump instead. So that means if we take the light from a galaxy and split it into its rainbow to get a trace of how much light at each wavelength is there we can look for the dips that show there's carbon or iron present in the atmosphere of stars in that galaxy or the bumps that show there's say oxygen in the gas that is glowing. But because that process takes time, right, for all of those heavier elements to actually build up in enough quantities so that we could actually spot them in this way, we didn't expect to be able to see this with JWST when we pointed it at the most distant galaxies, the faintest things that we could see because we're seeing them when the universe was so young and there hasn't been enough generations of stars. And yet, we still manage to see this with JWST. We've had direct detections of carbon, oxygen, neon, magnesium just 350 million years into the universe's lifetimes. And we've also had recent claims of iron being found in galaxies observed with JDST as well. And you might say, okay, well, that just shows how great JST is, the fact that we can spot this. But the amount of these heavy elements that we're actually spotting with JBST is way higher than we ever expected given our observations that we've made with the Hubble Space Telescope in the past and more than been predicted by our simulations. So again, there are a couple of ideas, you know, knocking about to try and explain this. We still don't know which one or if there is even one that could be responsible. Again, it could be that there are more heavy stars that form in the early universe that could produce the heavier elements quicker through what's known as a pair instability supernova. Or you could just have more efficient star formation happening in the early universe, which again would more efficiently produce your heavier elements. Or you could have more binary stars that formed. So to give pairs of white dwarfs, which would spiral together until they collided, which would give you a different type of supernova, which could enrich the universe with these heavier elements quickly, especially if that inspiral happened very quickly because these two binary stars had actually formed. So they were very close together, perhaps because the gas was denser, which would put them closer together than we see in the universe today. Or maybe there's just something else going on, some new physics that we haven't figured out yet. Then finally, last on my list of JWST ### [10:55](https://www.youtube.com/watch?v=Qu15C28QW8c&t=655s) The Little Red Dots mysteries is the little red dots. These are distant galaxies that in images look exactly what it sounds like, like little red dots. So their appearance in images suggests first of all that they are very compact because they're so small. And then the red color suggests that they are mostly made of like older smaller stars as opposed to like much larger you know like newly formed stars that look much bluer. But then if you take the spectrum of light from that galaxy, so you take it and you split it into its rainbow of you know how much light of each color or wavelength you get, then that picture of what we get from their images doesn't check out with what information we're getting from their spectrum, which do not look like anything we've seen before. They have this sort of V shape where you've got lots of UV light and lots of sort of visible into infrared light, but this drop in the middle. Now, having this sort of drop in visible light before you get to UV is quite common for a lot of galaxies. It's known as a balmer break. It's essentially a dip in the spectrum for wavelengths shorter than the light with enough energy to remove an electron from a hydrogen atom. Basically, it means there's a lot of what's known as ionized hydrogen there. So, literally, you're just left with the center of the nucleus, just a proton. And for that to happen, usually you need a lot of hot stars producing light with enough energy to be able to do this. But there'd also usually be a lot of dust, heavy elements from those massive stars that would obscure the UV light and sort of give you this step function down. The problem with the little red dots is that the UV light isn't hidden. You get this Vshape where the spectrum rises up again. And if you're thinking, wait, hang on, how are we detecting UV light with JST? It's an infrared telescope, I thought. Well, this light because it's from such distant galaxies is Doppler shifted all the way into the infrared that we see it with JWST. And so this Vshape just doesn't make sense. It suggests there's no dust there in these galaxies. But we have managed to detect the glow from dust itself in longer infrared wavelengths of light using the mirror instrument on board JWST. At least for some of the little red dots anyway. And if you're wondering, okay, well, what's dust? Well, it's molecules made up of their heavy elements like we just heard about. So these little red dots have really turned out to be a headscratcher cuz it's like their spectrum and their images are telling two different stories. And one idea that has been raised to explain them is that they contain growing super massive black holes again that we can see because of the material spiraling around them that glows. And that's cuz for some of the little red dots, their spectra also have emission from gas that has fast velocity suggesting it's spiraling around a black hole very fast. And that could account for that upturn in the ultraviolet light because material spanning around a black hole will be hot enough to glow in the UV. But again, you would need less dust to explain that. Although some people have suggested that if you have very dense ionized gas around the black hole in the galaxy, that could explain this. Either way here, you've got something weird going on. either you've got a growing super massive black hole growing in a way we're not used to or you've got stars forming dust distributed in a galaxy in a way that we're not used to. And I think that really is like the key theme that runs through all of these three mysteries from JWST. The early universe is just not what we're used to. It's not what we expected, which shouldn't surprise us, right? We're taught by science every time that we don't know as much as we thought we did. Because the universe, well, it likes to just keep on surprising us. --- *Источник: https://ekstraktznaniy.ru/video/15170*