Ep. 800: The Beginning & End of Everything - Part 1

A New Ad-Free Era

0:00Welcome to the show.

0:30Let's get into it.

1:00We know what we know. I'm Fraser Cain. I'm the publisher of Universe Today. With me, as always, is Dr. Pamela Gay, a senior scientist for the Planetary Science Institute and the director of CosmoQuest. Hey, Pamela. 20th season begins. We are old. I mean, it's amazing how— We are experienced. We are veterans. This show has been basically, along with you, my friend, my constant colleague for longer than anything else.

1:33Yeah. And it has been wonderful spending these past 20 years. My youngest child was two years old when I started AstronomyCast. He is now 22. Yeah. So this is episode 800. It is the 20th season. There was a little bit of, like, episode manipulation to make those numbers line up into, like, pleasing denominators. We're denominators, but still. Now, we have a gigantic announcement. And if you are familiar with the format of AstronomyCast, you probably already noticed, which is that we have removed all of the advertisements from AstronomyCast.

2:12This podcast is now ad-free. We have removed the paywall on everything on Patreon from here on out. Paying patrons will get early access to content. But we are now creating everything with no walls. Yeah. Totally ad-free. Yeah. Well, I was going to say, so just to let people know what happened, like, it was the summer, and Pamela was working on AstronomyCast, and I just kind of reached my brain.

2:45I read another complaint about the ads on AstronomyCast. Yeah. And, you know, we're in this era where the ad companies are just getting more voracious. They're paying out less money. We were giving up more and more of our podcast, multiple ads in each episode. The ads were, in some cases, fine. In other cases, were not a thing you would want to have play while you're in the car with your kids or be playing when you're at school. And I just hit my breaking point. And I was like, we just can't do this. And so I reached out to you and I said, let's cut the ads out of the site. And you're like, yeah, but we need money.

3:19It's true. I did do that. Yeah. And I said, well, you know, I did this on Universe Today. I cut out all the ads, and I made a leap of faith to the patrons to help us make this transition over. And it is not as much as was required for University, because we don't take a salary. We don't take any money from this. All that Astronomy Cast has to do is cover the cost of the team, the editors, the server costs, the transcripts, all of that. It's a lower number.

3:49But it is a number. And so we are now in, if we don't pull this off territory, then there's going to be some cutbacks that will need to happen. So what do we need, Pamela? So we're currently still under 900 patrons. That number has been ticking up every time I look. Thank all of you. But we need to get up to 1,500 patrons to cover the difference between what we were making with Patreon plus ads and what we need to make with just Patreon so that we can pay Aviva, Allie, Rich, who does a saint's job editing our chaos.

4:25And so we took a leap of faith. We have removed the ads. They are gone. Yeah. We've done the algorithmic ad. We just turned off all the algorithmic ads. We moved the entire podcast over to Patreon. Now we're going to have to go back through the older episodes and trim and clean and remaster all the episodes that contain ads. I've produced transcripts of every episode, so we know where the ads are. And it's now just going to be the work of the team to go through and hack them out. But when we are done, AstronomyCast will be beautiful and pristine.

4:57It'll just be the science conversation that you have come to enjoy without the ads. And you can play the show in confidence. So we are making a direct plea to you as a fan of AstronomyCast. If you like our show, if you want to give us a hand, help us hit that 1,500 patrons and make this leap of faith worthwhile. And if you can't support us financially, I totally get it. The economy globally is not the greatest right now.

5:29Just spread the word. Get other people to fund us. Let your rich uncle know that they, you know, first, addict them to AstronomyCast. And then second, let them know that they can help cover the expenses. And, like, I feel really confident that we'll hit this. And then I want you, Pamela, to experience the serenity that I experience at Universe Today where I don't think about ads anymore. I don't think about search engines. I don't think about AI slop. I don't think about any of that kind of stuff. I just think about following my curiosity and producing the best show that I can.

6:03It's the dream. It is the dream. And you'll love it. I promise. All right. Well, let's get into the show.

The First Three Minutes

6:10To celebrate our 20th season, we thought we'd go right back to the beginning of everything. Let's wind the clock back to the earliest moments of the universe where we'll measure time in fractions of a second as the foundational laws of physics were laid down and we experience the repercussions to this day. And there's no ad break. Pamela. It's glorious. Yeah. I get to just leap into discussing the science. Science. Yes.

6:39Normally, I think about my question when we're waiting for the ad break. But you know what? I just have to go into my first question. So there was a great book that came out called The First Six Seconds or something like that. I don't know if you ever read that. First three minutes is what I'm thinking of. First three minutes is that the one? Yeah. First three minutes. Yeah. Yeah. Yeah. So let's go. How do you want to tackle this? Do you want to go from time zero and go forward? Let's do that. It seems that is the absolute beginning. Okay. Let's do it. Time zero. Boom. Big bang. So this is where everyone's sort of like, yeah.

7:12Because we can only scientifically say what happened from 10 to the minus 43 of a second in time. And so prior to that, prior to that plank time, I, we, we, science breaks. Yeah. We have no idea. Yeah. Yeah. So T equals zero is a mystery we cannot answer yet.

7:44Right. Maybe ever. Right. And you know, this comes into that question of like, how do you, like what came before the universe? And I think we've done an episode on this and the gist was, oh, we don't know. And if we're lucky, there's some kind of echo built into the current universe that gives you some hint of what came before. But really, we have no idea. We have no way of knowing. All we know is time equals zero moving forward. It's the realm for artists and theologians and philosophers.

8:18No, it's science, still scientists. They just haven't found any evidence that they can even scaffold anything onto yet. Fair. It's a scientific question. It's not, it's not a, it's not a philosophical question. It is like either there was a universe before us or there wasn't. And, and science can figure out which one it is. Okay. But time equals zero moving forward. It's like inflation, right? Like what's next? What, what starts? So the next thing that happened, as near as we can tell, is there was this vast quantity of energy in our universe that went from heating things to expanding things.

9:00So our universe suddenly grew from roughly the size of a proton to roughly the size of a grapefruit, which doesn't sound all that outstanding because like grapefruit. Yeah, well, but I need to like really clarify here that our observable universe was the size of a proton and our observable universe ended up the size of a grapefruit that the, that I've heard volleyball, you know, you'll think roughly, but keep in mind, this is the universe that we now look at today. That is 93 billion light years across.

9:34And, and, and the reason observable is key is the reason we figured out this nonsense had to happen is when we look in all directions, things seem to be consistent in a way that only makes sense if information could travel across regions that should never have been within the speed of light of one another. Right. So the only way to explain that part of the universe and that part of the universe looking consistent with one another is at one point in time, the speed of light allowed information to travel between those two parts.

10:19And that requires the universe to have gone from proton sized to grapefruit volleyball sized at some moment in the first gazillionth of a second. Right. That the, that the, that the, at the, at the zero, the temperature, they were connected to each other. They had the same temperature. Then you had this moment and it was like a ludicrously small amount of time that they then expanded, essentially maintaining that connection, that temperature connection in a way that now the universe can remain homogeneous today.

10:56Which is, which is, this was one of the great challenges of the big bang. And so that's, that's really why inflation was, was developed as a solution to that problem. Things, things slowed down. Like, make, like, what is it? 10. And I forget the number. Like 10 to the minus 35. Like some unreasonably small fraction of a second that initial inflation happened. And that's what it took. So it, it occurred between 10 to the minus 43rd of a second and 10 to the minus 35th of a second.

11:30Right. Yeah. There's a lot of zeros involved. There's a lot of zeros. Yeah. Yeah. But it is not very much time and a massive expansion. And that's what, that's what it took to set the stage for the universe that we have today. So what happened after that? So initially, as near as we can tell, all the forces, gravity, electro-weak, electro-strong, electromagnetic, were a force. And we're still trying to figure out how you get gravity in there.

12:01We're trying to figure out how to get quantum gravity to be a thing. Haven't got there yet. But as near as we can tell, the first thing that happened was gravity split off and went, yo, I'm different. Right. And then, electro-weak and electro-strong together split off from the electromagnetic force. And though, and like, there are four fundamental forces in the universe, right? There's gravity, strong force, weak force, and electromagnetism today. Yes. And, and so you're saying like, like, initially it was just one thing, whatever that means.

12:36Like, like. Yeah. Nobel Prize is all around to figure out what that thing was. And gravity. This is called the Grand Unified Theory. Yeah. And this does not exist. Right. People keep trying. Yeah. Yeah. And Einstein went to his grave trying to figure out how to, how to make this make sense. They've got three out of four. Yeah. But the fourth one, gravity, is still just nonsense. No, it will not. Mangled in sight of nonsense. Yeah. But at some point, gravity detached from the rest of the forces. So, so it's, it started with, with the, the grand unification is, is the phrase that they use.

13:14Um, it breaks and the strong and electro weak forces broke apart. Okay. So, so sorry, I gave the four strong forces now disconnected from the, the rest of the forces. Yeah. And you've now got the weak force and the electromagnetism still as one force. That's the electro weak force. Yes. Give us a sense of time here. Where, where are we at when that, when that separation, you know, gravity is still question mark, question mark, question mark. But when does the strong force detach from the electro weak force?

13:47This is what's happening at 10 to the minus 35th of a second. Right. So when inflation ends, the end of inflation is when the, the forces start to. Strong force is like, I'm going over here now. I'm going over here now. Yeah. Yeah. And, and then we have the electro weak force splits at 10 to the minus 10 seconds. So we're at least getting the numbers that you can write down without getting annoyed and having to count your zeros. With your hand hurting. Yeah. Yeah, exactly. Right. So, so now the weak force and electromagnetism have split off from each other.

14:18So now we have the four fundamental forces of the universe. So what does the universe look like at this 10 to the minus 10? It's energy. That's all it is at this point is energy. And this is the wild thing about it is how do you even start to conceive of what that means when, so what is moving if there's no particles, what is temperature if there's no particles, it's just energy. And I have to admit, this is like one of those things where my brain is like, cannot visualize.

14:51I know the words, I understand the concepts, but it's not until about 10 to the minus four seconds that my brain starts to be conceptually happy with our universe as we start to get quirks combining to form protons and neutrons. Right. So, so before that, there was too much energy to allow particles to form. Yeah. And so when you think about there was just, it was just energy, but, but like, was it photons or was it just?

15:28It, it's, I mean, this is the thing where we're depending on where you look in the timescale, depending on exactly what theories you're looking at with the split of the electroweak force at 10 to the minus 10, you start getting quirks and anti-quarks. It's, it's, it's at that point that, that we start to see something coming into existence and we have this massive amount of annihilation that occurs. So at that 10 to the minus 10, we get quirks and anti-quarks and we don't get them in equal numbers.

16:03And, and so there's this another burst of energy that occurs with the annihilation of quirks and anti-quarks with one another. And then at 10 to the minus four seconds, we finally start to get protons and neutrons from that excess of regular quarks that exists everywhere. Right. Okay. And so now you've got essentially this soup of particles. Yeah. Um, I always describe it as like the interior of a star.

16:37It's like the interior of a star in terms of things are hot enough and close enough to undergo nuclear reactions. But it's, it's nothing like what we're used to thinking about because nuclear bariogenesis hasn't happened yet. So we have protons and we have electrons and then they start colliding in this high temperature, high density environment.

17:10And this allows hydrogen and helium to both start to exist. Right. So a lone proton by itself can either be called a proton or an ionized hydrogen, which is lame, but that's, that's as the case may be. So the universe was essentially initially ionized hydrogen. Right. At this point. Right. And then we have nuclear bariogenesis.

17:36Right. Right. So, so, and just to sort of let you, you know, I've, I've got a list of the sort of the sizes of the universe at different times. Yeah. So, you know, you mentioned the size of a proton at inflation and then it ended up the size of a grapefruit. Yeah. When we got to the electroweak transition, it was about 15 astronomical units. Well, the size of Saturn's orbit was the size of the universe at this point, the observable universe. Like we've got to be so clear, the observable universe. Yes. And then we get the quark hadron transition when the protons form.

18:09Now it's 0.1 light year. Yeah. Um, and then the next phase, the one you're talking about is the big bang nucleosynthesis, baryogenesis, and that is where it's 300 light years across is the size of the universe. And this is the period where we start to get the stuff that's necessary to form stars. So hydrogens, protons combine to create helium in the process, trace amounts of lithium and beryllium that are actually important, end up getting created as well. And by the end of the first three minutes, all of that is done.

18:44That's, and again, like, this is crazy that, that you had the entire universe, this ball of observable universe. And then outside that there was more universe, right? Like, like this was happening maybe in infinite directions in all ways, right? But we're just focusing on the part that matters to us, the part where the information could have reached us. And we do this because we don't know if the universe is infinite or finite. We just know that it's a four-dimensional hypertor, right?

19:15But, but it is the interior of a star and he's doing exactly what happens in a star that you're getting hydrogen turned into helium. You're getting trace amounts of other elements and that the, the quantities of, of those elements that exist today were frozen out in that first three minutes of the universe.

Cosmic Structure and Sound Waves

19:35And it wasn't exactly the same density everywhere. This is one of those things that, that often gets misunderstood. When we had that moment of matter and antimatter going, we don't actually exist in equal numbers. And, and, and annihilating and leaving behind that excess of what we now call regular matter, shockwaves started oscillating through this universe. And these shockwaves, which left behind residual densities and under densities over and under densities that led to galaxies and large scale structure.

20:18These were forming slight differences in temperature from one place to another. And that led to slight differences in how things reacted. That led to slight differences that led to us. So things that happened in those first fractions of a second are still reflected in the observable universe today. And that's amazing too. Yeah, it really is. Like if you look at the large scale, I'm sure you've seen these pictures. You know, these large scale structures of the universe, you see these, this cosmic web, you see these, these lines of galaxies and then these giant voids in between.

20:56And we'll get to the cosmic microwave background in a second that we see as regions of over and under density in the CMB. But if you go back to these first three minutes, they were there. They were places where the universe was hydrogen and helium, but there was like a little more density and places where there was like a little less density. Temperatures were a little hotter. Temperatures were a little colder. And that, that those regions of these lower and higher temperatures, higher and lower densities turn into strings of galaxies, a billion light years long surrounding a void that is 700 million light years across that in the far, far future, these will be tens of billions of light years across.

21:42Like, it's just that the, the physical structure of the universe today was just this infinitesimal little change between things not being exactly homogeneous at the time. Again, like we're going to run into superlatives. We're going to, you know, I'm sure someone's going to do the superlative watch for like, you know, Fraser said amazing 79 times. And Pamela said wonderfully, whatever, right? Fine. Guilty as charged. This stuff's crazy. And, and the thing is, we're still piecing together things based on what we can see today.

22:14And so there are theorists out there trying to figure out all of these things, making predictions that, well, maybe there were primordial black holes. And if there were in the size distribution that decayed at this rate because of Hawking's radiation, you'd see this. If there isn't Hawking's radiation, you'd see that. And so we're still in the point where as technology advances, as detectors advance, and as creativity advances, because science advances at the pace of technology and creativity. As these things advance together, we are seeing things in the universe that either prove or disprove these theories in the literature and allow us to make that next incremental step forward in piecing together the unviewable time of the universe.

23:04Right. And, and that of course is the part that's the great tragedy is that it is all unviewable in the electromagnetic spectrum because it was opaque that the entire universe, you can't see through the interior of a star. If you could slice the sun in half and see the core, you would not be able to, to look through it. It's actually worse than a star. So with a star, the light can actually eventually escape with the early universe. It was so dense that a photon trying to get from point A to point B would just get absorbed and reemitted and absorbed and reemitted and absorbed and reemitted.

23:42And it's this constant absorption process that makes us say the universe was opaque until about 380,000, thousand. We're dealing with thousands here.

The Cosmic Microwave Background

23:55But what came, what was in between? You've got three minutes where the end of the nucleosynthesis part happens. Yes. And then you've got, and we'll talk about the CMB in a second, but you've got this in between time. Yeah. And the in, in between time is the boring time in my brain because essentially you have a universe that is literally an echo chamber. There are sound waves, acoustic, there's acoustic waves that have a fancy name.

24:28Baryonic acoustic oscillations. That's the phrase I cannot apparently say on only two cups of coffee. Thank you. So you, you've, you've apparently had more, more coffee. These waves are, are echoing through the universe, interacting with one another, creating these areas where the interactions lead to smaller places, where the interactions lead to larger places of different densities. And so at that point, it's, it's just expansion and sound waves interacting with each other.

25:00And, and I love the idea that we refer to our modern day as we live in an echo chamber, but the universe was actually an echo chamber early, early on. But you did have kind of more, like over time you had more energy. You had, you had matter, as you said, you know, the, the, you had the fusion going on. Yeah. It was producing heat through fusion and then it was producing, sort of producing photons through fusion and then it was producing photons through heat and you get more energy making its way into the universe.

25:35You know, about 50,000 years after the big bang, they're kind of equivalent and then things keep cooling down. Yeah. And, and so the big number that we're getting to is 380,000 years after the big bang. And when we're talking about cooling down, what we're referring to here is the collision rates and motions of the particles. So as the collisions slow, as the motions slow, as it becomes possible for photons to make it further and further before getting absorbed and reemitted, that is seen as temperatures decreasing.

26:13Temperature is one of those really funky things to, to try and explain. We experience it as sweat and misery. The universe experiences it as motion. Right. So what, so we're at 380,000 years after the big bang. Yeah. Um, what, what happened that makes this special? So prior to this, electrons and protons were moving at such high rates that they couldn't glom onto one another to make neutral gases.

26:48So we had cores of hydrogen atoms. We had cores of helium atoms. We had trace amounts of cores of lithium and beryllium atoms. But they're just collections of protons and neutrons flying around the universe with the electrons flying completely separate and free. And from about 379,000 years to about 470,000 something years, depending on which theory paper you read. So for about 100,000 years, things cooled and they cooled at different rates depending on the density.

27:21So the less dense areas cooled first, the high density regions cooled second or last as the case may be. It's those baryonic acoustic oscillations returning. Yes. And, and, and as things cooled, the protons went mine now to the electrons and they created less stuff for all those photons to interact with. And those photons began to fly free. Right. In a universe made of neutral gas. And when I sort of, so first at that moment, the universe kind of looked like the surface of a red star.

27:59This is sort of the way I always describe it. Like the temperature was like, I forget, like 3000, 3500 Kelvin. Like, like it is Betelgeuse, but it is the entire universe. And again, it's the observable universe. We sort of imagine is this sphere. And at this point we're looking at something that was, uh, like 85 million light years across. So it's a sphere, 85 million light years across that is kind of like one big red star, but the entire contents of it are also like the surface of a red star.

28:29And it's only one part of an infinite universe, right? Like these analogies only go so far, but, but as you're, you know, you're saying, and we don't hear this often enough. I think that this idea that there was about a hundred thousand years where the particles were starting to spread and you, and you got like photons going zip. Wait a minute. I can move. Right. I can go a centimeter. Oh, I hit a particle. And then later on, a photon was like, I got a meter. Oh, I got a kilometer. Oh, I got a light year. Right. Yeah.

28:59Like these things are starting to make distance that they can actually travel. And, um, and this has another side effect that we also like, this is something I know. We've done a pretty good job bringing up, but I, I, it's just, I don't see it enough in books and articles. So where we are in the universe, we look out in all directions and we see from that same hundred thousand year period, this depth of universe emitting the cosmic microwave background. Now, if we zipped over 7 billion light years away, we looked out, we'd see a different sphere around us.

29:39Yeah. A new observable universe. Every single point in the universe started emitting photons in every direction. So no matter where you go, you're going to see your own distribution of the cosmic microwave background. And what's cool is while the distribution of hot and cool spots, those blue versus red that you see in maps from like the Planck satellite, where those spots appear will vary depending on where you are. But the number of small and the number of large statistically will be the same no matter where you are, because those are reflecting those, I'm going to try and say it.

30:18I'm going to do it really, really slowly. Ready? Baryonic acoustic oscillations. Nice. So we see our distribution and no matter where you go, you see the CMB. It has the same distribution in a different picture everywhere. And again, when you think about that idea of the, you know, the gaps are starting to open up, the photons are getting a moment to move. That when we look at the CMB, we're seeing this moment of last scattering, this time when all of that, those photons were able to make the journey.

30:56And you're only seeing the survivors, right? That as the CMB was starting to happen, as the photons are making these, most of them were just crashing into other atoms and they're not visible. But every photon that we pick up in our surveys of the universe completed the journey. They were able to travel 13.8 billion years of time and 42, no, 46 and a half billion light years of distance.

31:31Because the universe has been expanding. Because the universe has been expanding. We're moving. The place has been moving, right?

31:36Unobstructed. They are the lottery winners. Those are the photons that made the whole journey and they never crashed into anything. We don't see the ones that didn't. And yet, from what we see, we can build up this view of the entire universe in the beginning. And then chaos occurs.

Cosmic Dawn and Reionization

31:55Chaos or darkness? The messy middle begins at this point. So the universe starts out as neutral and boring. Neutral is always boring. But then either around some of these primordial black holes or because the over densities have gotten big enough or both, the universe likes to say yes. And you start to get the first stars, the first supermassive black holes, the first structures forming. And the theories we had for the time scales and the way this occurred prior to the launch of the James Webb Space Telescope were very different from what the universe decided to actually do.

32:36And so this is where, as cosmic dawn appears, as things begin to light up and high-energy photons from those first stars, from accretion disks around early black holes, as ultraviolet light begins to permeate that gas, it re-ionizes it. It makes the universe ionized and transparent. Right. So you skipped a phase. I did. I do this. Right. Which is fine.

33:09But essentially, we got this idea of the universe cooling down and cooling down and cooling down and cooling down. And you get this moment where the particles are all ionized and they've let out those photons and the photons are able to survive to reach your detectors. But the universe keeps cooling down and cooling down and cooling down and cooling down and it goes dark again. Yeah. The cosmic dark ages. And these are the cosmic dark ages. Yeah. Right. And so the universe turns into this neutral gas that is no longer emitting the same level of radiation.

33:39It's like it's cooling down and cooling down and cooling down. And then gravitational over densities, maybe that baryonic acoustic oscillation is driving material into places, causing stars, supermassive black holes, the first galaxies to start forming within this neutral gas that was dark. Yeah. And even opaque. Yeah. And lighting it back up again. Yeah. And so we go from the microwave radiation can go straight through all this neutral gas to a period where everything is like when we look through the disk of our galaxy and we see dark bands of gas making it impossible for us to see the star formation.

34:27So there's this period where when we look back far enough, we start seeing clouds of neutral gas obscuring our ability to see things. And then that gas gets made transparent. And this is where JWST keeps finding this stuff was happening so much faster than we thought, so much earlier than we thought. We thought that it would easily be able to see how structure formed in the first billion years, except it turns out structures were already forming 600 million years after the Big Bang, way too early, way too early.

35:04We need bigger telescopes already. Yes. Yes. But I think I always sort of envision this like fog wrapping around a lighthouse or fog wrapping around. So you can like look, you're on a ship and you're looking at the coast and the coast is foggy, but there's this little lighthouse there and the fog is not, has not enveloped that lighthouse. And that lighthouse is one of these new stars or galaxies that are forming. Fog, you can't see the rest of the stuff, but you can see where the fog has opened up. And what James Webb is doing is it is looking out into the universe at this time when the fog was lifting, seeing the objects that it could see at that time.

35:44And as you said, a bigger telescope will get us better views. Maybe new wavelengths will let us push through that fog. But it's kind of as early as you can see because again, you have this fog that's there. And like one of the greatest discoveries that James Webb made was that we now sort of understand what was responsible for the ultraviolet light that was clearing out the fog. We thought it was the big galaxies. Now it looks like it's probably the dwarf galaxies. And in fact, you've got this constant radiation that is coming from all of these galaxies, this everywhere that is blowing away all this material into space, clearing the fog.

36:21And then that leads us into, you know, the universe we have today, stars, galaxies, planets, plants, spaceships, you know, books, TV shows, video games, blah, blah, blah, blah. So we're going to now just skip that boring middle. It's true. It's very boring. You know, whatever, you know, stars, galaxies, life, existence, the future. We're going to move into the end of everything. And that'll be our next episode. All right. So for those of you watching live, we love having you here.

36:53I'm probably going to have to blink the stream. And those of you on YouTube are going to have to skip over to the other video. Now, when we edit this together, we're going to put in the names of the patrons who are joining in real time. It's amazing. I'm going to update all the names to make sure you end up in this episode. This month, we'd like to thank the following patrons for all of their support here at Astronomy Cast.

Thanking Our Patrons

37:17Now, if you notice that list is a whole lot shorter than it was last year, this is because we have updated our Patreon tiers, moving around some benefits to reflect the effort it takes our team to do things. Believe it or not, reading your names is one of the most stressful things I do because I really struggle with pronouncing things and feel bad when I screw up.

37:55We've moved Read Your Name to the $50 and up tiers, meeting with you once a year to the $20 and up tiers, adding your name to the end of videos to $10 with lower and higher tiers remaining unchanged. Thank you. You are what makes this show possible. All of you in all of the tiers. Okay. Thanks, everyone. Thanks, Pamela. And we'll see you next episode. All right. Bye-bye, everyone.

38:38Love it, share it, and remix it, but please credit it to our hosts, Fraser Cain and Dr. Pamela Gay. You can get more information on today's show topic on our website, AstronomyCast.com. This episode was brought to you thanks to our generous patrons on Patreon. If you want to help keep this show going, please consider joining our community at Patreon.com slash AstronomyCast. Not only do you help us pay our producers a fair wage, you will also get special access to content right in your inbox and invites to online events.

39:11We are so grateful to all of you who have joined our Patreon community already. Anyways, keep looking up. This has been AstronomyCast.

39:24Transcription by ESO. Transcription by ESO. Translation by —