Will Roman Find Even More New Physics? | Q&A 456

Will new telescopes continue bringing up new discoveries? Why doesn't the CMB get blocked by galaxies? Where did the first stars form? And in Q&A+, the truth about Roman's mirror. All this and more in this question show. It's time for the question show, your questions, my answers, as always, wherever you are across my channel. If a question pops in your brain, just write it down. I'll gather them up and I will answer them here. All right, let's get into the questions. My name is Tau. When the next generation of space telescopes are launched, do you think we're going to be shocked with more discoveries of little red dots, more distant in the early universe or not? We have no idea. And just in general, I want to tackle this question kind of in general. Because yeah, when James Webb launched, one of the really exciting discoveries was this entirely new class of objects that astronomers had never seen. This is the little red dots. These are weird objects that were reddish at the time, like giant betel juices. And yet they were probably tens of light years across. And what they are, people are still trying to work out, were they supergiant stars? Were they black holes surrounded by an envelope of hydrogen gas that they're feeding on? We still really don't know. But we do know that they appeared early on in the universe, and then they disappeared, that they evolved into some other form. So around us today, whatever little red dots were, we see the future version of this around us today. And this was surprising. This was a totally new thing. So what would it take? Yeah, a next generation telescope, a super version of Webb, which unfortunately, there are none in the works. There are no plans to build a super version of Webb. But something like that would try to look a little bit earlier and try to see what these objects were before they even evolved into little red dots. But we can see what they evolved into. And that is what the ongoing work is going to be from this point on, which is that astronomers are going to be looking for examples of little red dots in different phases of their evolution. We've seen them in the phase where they are little red dots, but there's going to be this time when maybe if it is a black hole, and the black hole is creating material and it's pumping out radiation, and that radiation is clearing away the hydrogen gas, we'll see this transition from the black hole surrounded by hydrogen to just the naked black hole. But you know, this is a mystery, and it's going to take a lot of work for people to figure this out. But the other path of this that you want to do is to be able to see it as it is under formation, whatever were the elements that led to whatever became the little red dot. And this is going to be a tricky observation because these are appearing at a time when the universe is just coming out of being opaque, where light wasn't able to move through the universe again. So you had the cosmic microwave background radiation before that, the universe was opaque, then light could get out, and then the universe went through the dark ages, the cosmic dark ages. And the time that we're seeing these little red dots is around the cosmic dark ages. We're seeing them embedded in the original dark clouds of hydrogen that are just starting to clear up, and this is the epoch of reionization. And then the universe cleared out again for the second time. And this is a really tricky observation to make to be able to see into that hydrogen fog that was there in the universe. There's a couple of ideas for this, which so far have not been pursued. One of these is the Origins Space Telescope. So originally we had James Webb, and then NASA was looking at four telescopes, ideas that would come after James Webb. The one you're probably most familiar with is LUVOIR, the Large Ultraviolet Infrared Observatory. That was going to be this maybe nine meter, maybe 15 meter telescope that would be able to be a true replacement for the Hubble Space Telescope. It would be optical, it would be ultraviolet, it would be infrared. 15 meter telescope, primary mirror, yes please. That has merged with one of the other ideas, which is HABEX, into this Habitable Worlds Observatory. But the other idea, well there was an X-ray observatory called LINX, and then there was the Origins Space Telescope. This was going to be a follow-on to James Webb, but it would be a nine meter telescope, and it would hope to pierce into the cosmic dark and try to sort of see what were the conditions that led up to the first galaxies in the universe. The other idea, and this is going to be more practical, and we're going to see progress on this, which is to look at the 21 centimeter line, which is this emission given off by hydrogen early on in the universe. They would put a radio telescope, say, on the far side of the Moon, blocking all of the radio transmission coming from the Earth. That would allow them to perceive where the hydrogen was in the early universe. So you can kind of put those ideas together, that if you are looking at the 21 centimeter line, you're seeing the distribution of hydrogen. If you're seeing these big blobs of hydrogen, those could be little red dots in the making. But just whenever you get a new telescope, that unlocks a whole bunch of new things. Think about all of the objects in the Kuiper Belt that were discovered around, say, 15 years ago. You had Eris, you have Quawar, you have Makemake, you have a whole bunch of these objects. Well, those were discovered because a powerful new telescope came online. The European Southern Observatory's Very Large Telescope, essentially the largest telescope on Earth, delivered new objects in the Kuiper Belt because nothing else could look that far. So now James Webb is online, and what do you know? A new class of objects are discovered. We're going to get that over and over again. Whenever you get a new type of instrument that is designed to do the job perfectly, then you're going to get examples of objects that before were extreme, over the horizon, something you couldn't see, which now suddenly you can see them. Then you see a whole bunch of them. What's kind of amazing about this is that once one of these things is seen, then you can go back to other instruments and go, wait a minute, could we see that in another wavelength? Oh, it turns out we could. For example, the Chandra X-ray Observatory has been doing X-ray observations of little red dots because they know where to look now, thanks to James Webb. Just like in general, whenever a new telescope comes online, it will enable new kinds of observations that had never been seen. You're going to see the new low-hanging fruit of the next class of object that's out there. The one that we're all going to be excited about is what we're going to see with Nancy Grace Roman, which has now launched and is now on its way out to the Earth-Sun L2 Lagrange point. It's time to shout out all the new $5 patrons and above. Vladislav Gichev, Wes Kaifa, Jolly Goodfellow, Weyla.Travel, Daniel Thompson, Joanne Mulvey, SD, Flip Flan, Dave Thins, and Kyle Smith. Join the club at patreon.com slash universe today. Zeldaboard Galactic Defender. If CMB is the most distant light we can detect, why isn't most of it blocked by galaxies and other matter between us and CMB? So the Cosmic Microwave Background Radiation, the CMB, is the limit of what we can see in the Universe. It is, I mean, it is a place in the Universe. When we look out, it is about, say, 42.5 billion light years away from us. The light has been traveling for 13.8 billion years. It is 370,000 years after the Big Bang. So there's not much time before the CMB was released into the Universe. And so it is a point in space, and it is also a point in time. And that, you know, the evolution of the Universe is where, you know, the Universe started out in some hot, dense state. And then it cooled down and cooled down. And eventually, it was like the interior of a star. And that's how you got hydrogen being fused into helium. And that's why we have those ratios of hydrogen to helium today, that kept cooling down and cooling down. And eventually, the entire Universe was like the surface of a star. But you wouldn't be outside the star, you'd be like inside the first 100 kilometers of the star. And it's the whole Universe, right? That's what the Universe was like. And then it cooled down to the point that light could finally start to move around in this new Universe. And for most of the light that was moving around, it was just getting absorbed again by other hydrogen atoms. But some of it dodged and weaved and made the journey all the way to us today. And so like, why didn't it get blocked by galaxies? Because it made it through, right? That yeah, absolutely, that there was going to be regions in the Universe. Like if you look out into space, and you see the cosmic microwave background radiation is the most distant thing that you can see, there are going to be galaxies in the way. And the galaxies are going to block some of those photons from the cosmic microwave radiation. But galaxies are not opaque walls, they are filled with stars and gas and dust, and they are translucent. And so photons from the cosmic microwave background can pass through them, some of them are blocked, most of them get through. And so we're able to see the CMB at the largest scales across the Universe. There are examples where the Universe truly is dark. And the one that I always use is the example is the core of the Milky Way, which astronomers used to call the zone of avoidance, which is a region that is so choked with dust, that you just can't see anything that is inside the center of the Milky Way in visible light astronomy. And another great example is like dark nebulae. Think about the elephant trunk nebula. The dark nebula are clouds of hydrogen that have not been ionized. And so they are very dense, and they are blocking the light, then you literally can't see through them. And if there was cosmic microwave background radiation on the other side of those dark nebulae, or on the far side of the galaxy, where we would have to look through the center of the Milky Way to be able to see them, we wouldn't be able to see them. Miss Solar. So does that mean that the first generation stars were born in opaque dust clouds behind the CMB? So this idea of the dark man, this is gonna be a long one. So just like, buckle up. The Sun is like the third generation star, it is the most modern form of the star with all of the heavier elements that have been synthesized through previous generations of stars. There are other stars that are very metal poor, they are like the second generation stars. We see them in the Milky Way, they're out there, they can have like 1000th the metals that the Sun has. And yet, you know, they were present early on in the universe, and yet they still have some metal. And so it's assumed that there was another generation of stars that came even before the Sun. And that those were the first generation that they were made of the primordial hydrogen and helium that was forged in the Big Bang. And no one has ever seen them. And it's not from trying to look, you know, these things probably were very, very big, and they were probably very, very bright. If we follow sort of the modern understanding of how big a star can get, maybe these things would be stars with a mass of 100 times the mass of the Sun, 200 times the mass of the Sun. But there are theories that you could have really sort of special conditions early on in the universe. And that because they didn't have these other heavier elements in them, they could grow much bigger. Maybe they could be 1000 times the mass of the Sun, 50,000 times the mass of the Sun, a million times the mass of the Sun. Like the jury is still out on how big those first stars could have been. And so they would have been very, very bright, right? They would be incredibly bright. And when they detonated supernova, they would have been incredibly bright. But the problem is that they formed at a time when the universe was opaque. So we talked about this idea of the cosmic dark ages, that early on you had the first time the universe had cooled down to the point that light could escape, and the universe kept cooling down. And over the millions of years after the cosmic microwave background radiation was released, the universe kept cooling down and kept cooling down. And all of that bright ionized gas cooled down and then went invisible again. But it was all still there. And so you just had this incredibly vast, dense clouds of hydrogen. And it was opaque. You know, we talked about this idea of a dark nebula, the entire event is maybe this is my new analogy. Okay, yeah. The entire universe was sort of like a dark nebula, the light couldn't get through it. But it was star forming material. And so you had these stars were starting to pull together inside these clouds, this fog early on in the universe. And you got more and more of these stars, these stars probably lived and died, detonated supernova, other stars formed, detonated supernova, all within this fog. And then, you know, more and more stars, longer term stars are sticking around, and the radiation from all of those stars is heating up this initial gas, and getting it to the point that it turns transparent again. This is the age of reionization. And that's as far as we can see. And we see with telescopes like James Webb and other telescopes, even, we see this transition point, we see places where the cosmic fog is starting to lift, where those first galaxies are, we're starting to see them embedded in their clouds of gas. But, you know, the reason why we haven't seen that first generation of stars, partly is because they were probably happening when the universe was opaque. But there's been some really clever ideas about how we might see stars that were kind of like those first generation stars. And that is places where there was no enrichment of the hydrogen gas. So, there have been galaxies that have been found, regions, star forming regions inside those galaxies, where there's no metal, where the star forming region is just hydrogen and helium. And they're seeing star formation and even examples of stars in those regions. And so, they're sort of like an analogy. They're a sort of a later version of what one of those early generation stars might look like. And it's still like just a huge unsolved mystery in astronomy. Could those first generation stars get really big? If so, what was their life cycle? Could they direct collapse into supermassive black holes? I mean, all of this is on the table right now. So, it would be amazing if we could figure out a way to be able to probe that time. And the best idea right now is to use radio astronomy, you know, the idea of the 21 centimeter line. So, there's the square kilometer array that's coming online in Australia and South Africa. That's going to be in the 2030s. And then there are also ideas of putting a radio telescope on the far side of the Moon, and that they would be looking for the 21 centimeter line. Essentially, the emissions given off by neutral hydrogen, but redshifted over the 13.8 billion years of the age of the universe. And you need very long wavelengths to be able to do that. And it's very difficult observation to make through the Earth's atmosphere. But if you go on the Moon, far side, maybe you can observe it. And so, they would be essentially mapping out the density of hydrogen at the beginning of the universe, and then use that to find out, you know, is it just smooth and equally distributed across the entire universe? Or are there pockets and blobs of clearly concentrating objects embedded within this hydrogen? Because this emission can make it through the opaque hydrogen at the time. Digitally, you can watch the same video with no ads and get a bonus question over on Patreon completely for free. We call it Q&A Plus. This week's bonus question, the truth about Roman's mirror. I'll put a link down in the show notes. All right, those are all the questions that we had this episode. Thank everyone who joined me for the live show. We are now back recording our live shows. Everybody who put your questions into YouTube comments. I really appreciate it. I'm going to be talking about a huge shakeup that is happening over at Astronomy Cast. But first, I'd like to thank our patrons. Thanks to Abe Kingston, Andrea Pedretti. Oh, that was a surprise. Okay. Thanks to Abe. I know you're going to keep this, Chad. Okay. Thanks to Abe Kingston, Andrea Pedretti, Buldazar. Oh, I'm going to get through it. Okay. 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