What discoveries and insights made the biggest impacts in astronomy and physics? What were the biggest surprises? What results took the longest to achieve? I discuss these questions and more in today’s Ask a Spaceman!

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EPISODE TRANSCRIPTION (AUTO-GENERATED)

199 episodes, 199 episodes. When I started this podcast in January of 2015, it was just for fun a side thing to get some of my outreach desires loose. I just bought my girl phone, downloaded a simple editing software, wrote seven episodes and put them out there in the wild. And now it's this amazing community of supporters and patreons and and listeners. I get the best fan mail of any scientist from around the world. I'm humbled every single time you click the download button or the play button, and my voice comes through your speakers to transmit some complete knowledge of time and space. I can't explain how much of a joy it is to share all this amazing science in this beautiful universe that we live in with you. Thank you, but we're not quite there yet. 199 episodes, and we still haven't reached this show's goal of complete knowledge of time and space.

Like I said, like I've always said, my plan is that as long as people keep sending me questions, I'm going to keep answering them. We're not stopping until we've explored every little corner, every little facet of astronomy and physics. 199 episodes in the party is just getting started. So I thought a fun way to celebrate would be to make this episode and the next, uh, for those of you who haven't had enough coffee yet, that would be episode number 200 as a sort of clip show. Now, those of you who grew up in the nineties or earlier will most likely understand this reference. When a long running sitcom had to fill in an episode to finish out the season or to celebrate some important milestone, they would just dig through the archive and find the funniest bits for those of you who grew up later, consider a clip show like a longer, uh, Tiktok or YouTube video that strings together a bunch of other videos. But I am not a sitcom, and my longtime editor, Kay and please everyone give a round of applause or at least a firm nod of the head for Kay having to suffer through the editing process.

For all of these episodes, nobody has enough time to dig through the old episodes, so instead, we're just going to do the usual ask a spaceman thing and make things up as we go along. And in today's episode, I'm going to offer what I consider the top five discoveries made in astronomy ever in the spirit of a clip show. I don't think there will be anything new in here that you haven't heard before, but I hope it it is at least entertaining. And maybe if you hear the same thing, but in a new way or at least again, you gain some new insight. That's true of me. And I hope it's true of you, too. Now Top five discoveries made in astronomy ever This is going to be a very exclusive and rarified list, and as you might imagine, there are a lot of contenders out there. So to help make this list, I decided on the following criteria. Number one. I'm going to narrowly focus on astronomy, so major discoveries like I don't know, evolution or birth control or the top work are out.

Sorry, Maxwell, you're not on today's list, and I'm going to emphasize observations in this list because astronomy really is an observational science. But I will accept theoretical results when they have a strong observational component where strong here is, they measure decided solely by the selection committee, which is which is me number two. I'm looking for contributions that are both broad and deep. They not only make a radical discovery, but they spawn a completely new paradigm, a new way of understanding, a new way of looking at the universe in an entirely new sub field. I want a great importance here by the amount of change that the discovery makes. Third, I want to emphasize discoveries that are not obvious and were not a foregone conclusion where it took a brilliant astronomer or two to synthesize previous knowledge in a brilliant way or make a staggering leap of curiosity or just end up playing lucky. Some discoveries that we call important are important, but were going to happen no matter what, as soon as we had the technology and any knucklehead with a sufficiently powerful telescope pointed at the sky would find it out no matter what.

But there are certainly cases in the past few 100 years where was not a foregone conclusion that we would arrive at this insight or discovery, and so we need some originality, and the last grading criteria is that I, Paul M Sutter personally think that the discovery is neat. With that said, I would like to first introduce to you the honorable mentions who, while not making it into the top five list, still deserve well, honorable mentions. For example, every astronomer throughout antiquity that noticed something special in the sky like equinoxes or the regularity of stellar patterns absolutely critical for the development of astronomy, for sure, and a major important milestone every time it happened. But it was repeated dozens, if not hundreds of times in cultures around the world. So I can't just pin it on any one person or group of people. Sorry, also, honorable mention goes to the first exoplanet discovered tremendously difficult work, but confirmed what we had already suspected.

That the universe is full of exoplanets, and it was going to happen as long as we continued progressing in our sophistication of telescope technology. Similarly, for the cosmic microwave background, surely a big deal, but it was discovered on accident. There were theorists who predicted its existence based on the Big Bang model, and they were starting to put together a an instrument to go find it. And then it turns out some random radio engineers discovered it accidentally, and the Nobel Prize went to them, not the theorist who predicted its existence. I'm not salty about that at all. Also, we're not going to include in the top five list the discoveries of dark matter and dark energy. Sure, it's a stunning revamp of our understanding or lack thereof of the cosmos. But honestly, we've only got room for five. And there are some bigger discoveries that enable the discovery of dark matter and dark energy. Also, I think they're a little too recent. Yes, the discovery of dark matter and dark energy is important, but we haven't yet sorted out just how critical or revolutionary their discoveries are.

Another honorable mention goes to Friedrich Bessel, who made the first measurement of a distance to a star. It took 200 years of development of telescope technology to make that happen, but someone was gonna do it anyway did for Uranus and Neptune. We were gonna find those planets no matter what. As long as we stared at the sky with telescopes long enough, we were gonna find those planets last honorable mention. Hot. Take time. Galileo. I know, right? Here's my argument. Brilliant guy. Not a great listener, but that's beside the point. Made a ton of discoveries, but somebody, somewhere was going to refine the telescope and point it at space. Telescopes had been around for a while, but they were crummy and they were used on land or at sea. The best you could do is say, Oh, there's this ship on the horizon. I. I think that was the best we had. Someone was going to take the basic idea and refine it, Make the lenses polished in just the right geometries.

Make it just right so that you can actually resolve distant astronomical objects. Galileo was the first person to do it. Absolutely brilliant. Someone was going to do it anyway. And so I don't want to award points for discoveries that were simply going to happen. I know I know controversial opinion, but hey, that's fine. Feel free to disagree. We'll talk about it later now, without further ado presented in order of discovery, not order of importance, because I had a hard enough time just to generate this list. So I have no idea how to rank them. Feel free to debate this with your friends, family and strangers on public transportation. The top five discoveries in astronomy Number one, My man Kepler. I know, I know. I had a lot to choose from. Among the leading figures of the scientific revolution at the turn of the 16th century Galileo Brae. Copernicus. Who is it gonna be? Galileo? We've already talked about Tyco. Brahe. Brilliant astronomer, for sure. Perhaps the greatest naked eye astronomer ever to appear on this planet.

But he committed one major sin. He was wrong. He collected all this fabulous data, made all these amazing observations. But he didn't develop any new critical insights that launched new fields. He didn't give rise to any new ideas that form the cornerstone of modern astronomy or our knowledge of the universe. He is a great observer, but not a great thinker. If that's fair And he did develop a revolutionary cosmological model that was way weird. I don't even remember the details. It's like the the sun revolves around the Earth or the earth revolves around the sun. But then all the other planets revolve around the Earth or I. I probably have it backwards. I don't even remember. It was It was weird, and it was wrong. So with all that data, all that excellent skill and observation that he was able to have, he came to the wrong conclusions, Copernicus. Hm? Yeah, he published the idea of planets moving around the sun.

Neat idea. But honestly, his arguments weren't the greatest. Yeah, it it kick started a lot of thinking, but his actual case for the Earth revolving around the sun wasn't all that strong. Previously, astronomers in Europe at least believed in what's called the Ptolemaic system, where the earth was at the center of the universe and everything revolved around the earth in these perfect circles. But perfect circles don't match up with the observations of the motions of the planet. So you have to explain that somehow And so they added what are called epi cycles, which are little circles and circles. So, like a planet is moving in a circle and then and it's a big circle. And then it's also moving on this little circle that's on top of the big circle. So you get this kind of swirly motion and you add a bunch of epi cycles to explain the data. Now, Copernicus said, Hey, maybe instead of planets revolving around the earth, all the planets will revolve around the sun. But he still insisted on circles, and so he still needed epi cycles.

So it wasn't exactly that much cleaner of a model. Plus, the model introduced some very puzzling questions like, If we're moving around the sun, how come we don't feel it now? Today we have an answer to that question, but 400 years ago they didn't. Copernicus had no answer to that question. It simplified some things, but it also introduced some very uncomfortable questions that Copernicus was not able to answer. And so I can't give him full credit. So I have to go with Kepler. Johannes Kepler, an absolute whack job of a man roughly guessing here that 99.999% of what he wrote and thought and argued was dead wrong and honestly, not just a little bit wrong, but so far outside the mainstream, thinking that even his peers thought he was a little a, for example, Galileo did not like him at all, and all of that naturally endears him to me, and even with the stuff he got right, he got it right for the wrong reasons. But he still got it right, and he still made major insights.

His first big major insight was that the planets moved in ellipses. Now this theoretical insight was based on intense study of planetary motions, gobs of data. And he did all this before the invention of calculators. So this is months, if not years, of pouring over handwritten tables of planetary motions and movements and positions and coming to this conclusion, that is, that is not something that every human is capable of. And his insight that the planets moved in ellipses is a big deal because it finally finally finally finally created a simple model of planetary motion. No more epi cycles, no more circles and circles. No more trying to come up with ever more intricate ways to explain the data using an inadequate model. And Copernicus's model was the same. Kepler's model was different by saying that the planets moved in, ellipses done. That's it.

Never before in human history had we had such a simple mathematical model that could explain so much. Now the wrong reason he had was he was looking for the music of the spheres and the harmony of heaven and the voice of God, Not the greatest foundation. But, hey, he got the right answer. And the second right answer we got is that he discovered a relationship between the period of the orbit of the planets and their distance from the sun. A simple relationship that held for every single planet. Just Wow, This is the first time again in human history that we had a universal law, a mathematical law describing something in space describing many things in space. The motion of every planet in the solar system obeyed this simple law. This is the first time we had a universal law in all of modern science is based on the concept of universal laws that we can find simple mathematical descriptions for a wide variety of phenomena in nature.

That is science. And that is why this is called the scientific revolution. Even though they were going after this for all the non scientific reasons. Like in this case, Kepler was trying to build better horoscopes, but he got it right. Kepler took tentative threads from all of his predecessors and contemporaries and put them all together into a simple, coherent hall hole. I would say that he was the first one to develop a modern theory of the universe, a theoretical result based off of gobs of observations. You know, the whole thing about Newton's laws, Newton's universal gravity, all that started with Kepler. We couldn't have a Newton without a Kepler. That's why I put Kepler first. Because without him, the whole thing doesn't even start. Kepler was the first to organize the motion of the planets in a simple, singular equation. A universal framework. When it comes to major advances in science, how much bigger can you possibly get than founding the modern philosophy of science itself?

For that, he deserves a spot on the list. Number two. Walking on the Sun for the next one. We need to jump forward a couple 100 years. Yeah, that's right. I'm skipping Newton because Kepler laid the foundation that Newton worked from. So we're gonna talk about the funky sixties. The 18 sixties that is. The American Civil War had just ended. The surfs are free in Russia, Canada happens, and something very strange is happening in the world of chemistry. I know, I know this is an astronomy focused episode, but work with me here, I promise it will be worth it. What we're seeing here in the mid 18 hundreds is the birth of spectroscopy. You see, by this time we had figured out that there were different fundamental elements in the universe and that everything that comprised the material existence was composed of combinations of these fundamental elements. And we were beginning to discover that we could identify these elements in one way was from the light that these elements give off.

If you take a fundamental element like hydrogen or oxygen or silicon and you heat it up, it glows. But it doesn't glow at all wavelengths of light. Equally, when you look in a detailed way at the amount of light given off at every wavelength by this element, you don't see this broad spectrum of all sorts of wavelengths, all sorts of colors. Instead, you see, like a fingerprint, very narrow lines like light at this specific wavelength and this specific wavelength and this specific wavelength. And together they add up and they give us the spectrum of that element. We were just beginning to figure this out, and at the time we didn't even know that atoms existed as a side note. This whole thing about spectroscopy and how do the elements give off very specific wavelengths of light led eventually to the foundations of quantum mechanics. The job of quantum mechanics was to explain atomic spectra, but we're not there yet.

We're at August 18th, 18 68 India Total Solar eclipse. French astronomer Jean He's staring at the sun, which I do not recommend you try at home. He saw a strange new emission line in the spectrum of the sun. Weird. Many people at the time, including him, thought it was kind of sodium you. It looks sort of like sodium, maybe really, really energized sodium. So it's, uh, Spectrum was a little bit off and not exactly sure what to do with it. Two months later, the English astronomer Norman Lockyer saw the same line and realized it wasn't kind of odium, but something else, something new, an element never before seen with a tremendous amount of confidence. He named the new element after the Greek word for the son Helios Helium. We would have gone decades, even centuries, Without noticing this, Jansen and Locky don't get nearly enough name recognition.

This was the first time that we found an element outside of the Earth. It would take two decades for scientists to find helium on the earth. And how do they find it through its spectral lines? Why is this on the list? Because spectroscopy has unlocked all. And I mean all of modern astronomy Spectroscopy tells us what stuff in space is made of. I can't go to the sun and lick it to figure it out. I can't go to a distant asteroid or a nebula and scoop it up and put it in a box and light it on fire. You know I can't do that. How do we know what the sun is made of? How do we know what asteroids are made of? How do we know what distant nebula Galaxies are made of? Through their spectra? We collect the light from the object, and we look for those fingerprints of the elements. All of modern astronomy is based on the spectrum people and a over the pictures. Meanwhile, the astronomers are drooling over the spectra.

That's where we get the work done and spectroscopy as this hidden superpower tells us how fast things are moving from the Doppler shift. You can recognize in a distant galaxy a familiar element, but it's shifted to longer or shorter wavelengths. That shift can come from a Doppler shift from movement. You can measure a speed. Every single major scientific observatory in the modern age includes a spectrometer, because that is what we care about. We care about what stuff is made of, and we care about how it's moving. Can you imagine what modern astronomy would be like if we hadn't unlocked spectroscopy if we hadn't discovered elements outside of the Earth? The identification of elements outside of the Earth brings the universe to us because we can't go to it. It's a gift from nature. How small? How limited would our universe be without spectroscopy? Now you may argue it would be inevitable, but I would say it took a lot of very clever insights and leaps of imagination to unlock spectroscopy.

It was not a foregone conclusion, and to realize that we could use spectroscopy in space Number three, Hubble's double trouble. Speaking of a small universe, our next entry is about to blow the whole place up now. This was honestly an extremely tough one. The early 20th century was ripe. We're looking here at the birth of modern cosmology, which was an epoch defining moment, one we are still grappling with. Actually, it was here in this period of time and no other that we radically permanently altered our view of how the universe works. And going through this there were dozens, if not hundreds of powerful figures, geniuses all working on separate pieces of the puzzle, all finding little scraps of data, all pushing just a little bit further into the unknown. There were tremendous leaps in theory and insight. There were revolutions in technology that enabled new observations. And there are reasons that I call this the second cosmological revolution.

The first cosmological revolution is more commonly known as the scientific revolution, but it really was a remapping of the cosmos. This is the second time it happened going into the 19 twenties. We believed that the universe was static and eternal. Yeah, OK. You know, planets move around the sun, uh, stars move around. Sometimes they they die. Sometimes they explode or merge together. Whatever But the universe as a whole has always been here forever and always will be here forever. Going out of the 19 twenties, we believed something else. On the theory side, we have none other than Einstein himself, who, of course, developed general relativity, which by itself was not a foregone conclusion. I strongly believe that if Einstein had not been alive at that time, there is a solid chance we would still not have a theory of general relativity. We'd have some theory of gravity, but it would not be general relativity.

Which, of course, puts Einstein in the running for a major discovery, as it was a completely new way to view the force of gravity. But I'm not gonna give him full credit here because one it was largely a theoretical insight and and so not necessarily astronomy. I don't think he even ever looked through a telescope, and he got it wrong. You see, Einstein developed general relativity and using general relativity, he predicted a dynamic universe. His equations told him that the universe was naturally either expanding or contracting and that a static universe would be impossible. And in a rare reversal for Einstein, he almost always stuck to his guns, always stuck to what his equations told him, regardless of what the observations were, and he was almost always right. But this time he didn't stick to his guns. The prevailing wisdom was that the universe was static, and so he introduced a fudge factor into general relativity to make the universe static.

If he had stuck to his guns, I would have given this all to him. But he backed down. So it was up to the observers. And there are a lot of people that led up to this result. Levitt and her discovery of Sey had variables Saul, Peter and his arguments about Galaxies leme in his prime atom idea. But ultimately, if we're gonna focus on astronomy, it was Edwin Hubble using, at the time, the largest telescope in the world. His first major discovery was that Galaxies are a thing, that the Andromeda Nebula was actually the Andromeda Galaxy and sat millions of light years away from us radically changing the scope of our universe. And his second major result, just two years later, was that the universe is expanding. Hubble's papers are actually quite simple and straightforward. Very well written and very clear. He reports what he finds, which is the red shifting of Galaxies based on the identification of atomic spectra. And at the end, he just straight up says, I'm paraphrasing, Yeah, So I think old Uncle Albert may have been right the first time and we live in an expanding universe.

We live in an expanding universe, look outside your window and realize that the universe that you are existing in right now has not always been this way. That change isn't just a feature of our lives or the Earth or the story of the stars. This is something baked into the universe itself. Yesterday the universe was smaller. Tomorrow it will be bigger. Our universe is changing and evolving. This is a radical departure from all previous scientific thoughts. Modern cosmology started here with Hubble's observations. That's why I say things like dark matter and dark energy. We don't get to that without the realization that the universe is expanding. And it was not a foregone conclusion. Seid, as a distance measure, were untested and unproven and a radical idea. Many people at the time did not like Hubble's results. The Big Bang idea was debated for decades before it was settled.

Without people like Hubble, we may not have made that connection, and our universe may have stayed small. His methods were so clear, his data so compelling that we had no choice but to eventually accept the Big Bang theory. Number four. Patreon. You knew this was coming, so I'm not even going to make this clever. 100 and 99 episodes, and the next episode will be number 200. It's because of you. It's because of your downloads. It's because of your listens, and it's because of your support. How do I thank you? I. I can't I could just say it, but that's not enough. So I think I'll thank you by just keep creating episodes. Patreon dot com slash PM Sutter. If you can contribute, I sincerely appreciate it. You get access to ad free versions, early episode releases if that's worth it to you, and I hope it is contribute. If you just want to keep the show going, you can also contribute patreon dot com slash PM Sutter OK, actual number four. Something wicked that way goes.

Black holes are weird, beautiful, frustrating, enigmatic. suspicious, a puzzle begging to be solved on scales from the subatomic to the Cosmo logic. Black holes are there always mocking us. And for a long time we insisted that they shouldn't exist. They first appeared in the mathematics of general relativity. Thanks to the solutions of Carl Schwartzchild. You see, general relativity is a machine. You apply it to various problems to see how the problem will evolve. You, you give it a setup. You sh You put in the inputs of what your problem looks like. Like OK, I've got a star surrounded by some planets. And then you you turn the crank on the side of the GR box and out pops how the system will evolve, how it will behave. And so you have to put in the situation to get GR to give you an answer. And in short, C, as I like to call them, was one of the simplest setups you can do. I want a ball of matter at the center of an infinite expanse of nothingness.

Give me the equations that describe this scenario. Very simple setup. He found the solution and he found that there is a special distance away from the center of that ball of matter where things get weird where everything blew up to infinity. When you run the calculations, there's this weird distance where everything's infinity. Now we call that distance the short shield radius in his honor. At the time, people didn't really know what to make of it. Uh uh, today we realized that you can just do a transformation of the equations to make it go away, and so it's not actually a big deal. But when we first discovered it, it it seemed like a big deal. And normally these kinds of infinities, uh, it was not a problem, because the balls of matter that we knew about in the universe like stars and planets were always bigger than this special radius. So it's like, Yeah, yeah, OK, the equations of GR break down at this weird special radius. But all of all the problems actually that we're trying to solve in the real universe, everything's bigger than that special radius.

And so it's no big deal. But the obvious question remains. What if they weren't? What if you squeeze something down below that threshold below the short shield radius? What would happen. Calculations suggested that it would be a catastrophic collapse, an overwhelming gravity leading to a point of infinite density, creating a region of space time closed off from the universe where nothing, not even light, could escape. Cue the furious debate. Most people dismiss the idea altogether, saying that it was a mathematical artifact. I mean, GR is nice and all but not Let's not pretend it's flawless. I mean, Albert did boff that all expanding universe thing, You know what I'm saying? So maybe this was just a Yeah. General Relativity predicts the existence of these weird objects that can close themselves off from the universe, but it doesn't actually happen. It just goes off the rails. It lost the plot a little bit, but meanwhile, we can use it on all problems of actual physical interest. Some theorists were, however, developing and extending the idea of these so-called frozen stars, as they were called at the time, toying with them as unrealistic but fun applications of a model of gravity.

You know, something to pass the time between grand applications. Other theorists were pushing on the boundaries of astrophysics, trying to fashion stars as small as possible. People like Shandra, Sekar and Oppenheimer worked on this, discovering white dwarfs and neutron stars. Still other theorists were pushing back at the idea of finding clever new excuses to prevent their very formation like, Oh, white dwarfs couldn't form or neutron stars couldn't form. Or OK, if you want to get smaller than neutron stars, some other force will stop like gravity can't always win. And so it was up to the observers. First came the detections of white dwarfs, then neutron stars proving that these exotic objects could exist. So our theories were on the right track. And then, in 1964 a sounding rocket launched from White Sands, New Mexico. It carried a Geiger counter, and it was attempting to map the X-ray radiation coming from deep space. Our atmosphere is crazy, good at blocking X-rays, which is good for us, so we need to go above it to get a clear signal of of X-rays.

Coming from space and deep in the heart of the constellation sickness, The swan was an incredibly bright point like source of X-ray emission. A decade later, astronomers Ricardo Cicconi and Herb Gerski successfully lobbied NASA to develop an X-ray satellite named Uhuru from the Swahili word for Freedom. This satellite monitored the X-ray source, now known as CGNU X one, and saw variations in that x-ray signal in as little as a second. It changed its x-ray brightness in as little as a second. This allowed astronomers to place an upper limit on the size of the source because changes in an object can only propagate at the speed of light. So if you see variations across the object in less than a second, you know it has to be smaller than one light second across. So it was very small. Still other observations found the location of the source, which was a red giant star which, uh, shouldn't be able to produce so many X-rays.

So more observations revealed that there were two objects in the system. There was the red giant, and then there was whatever was actually generating the X-RAY source. The variations gave a size. The orbital motions gave a mass putting that together gave a density and that object snu X. One was the densest known object ever denser than a white dwarf, denser than a neutron star, denser than anything. It was the first confirmed black hole. And now black holes are an entirely new sub-field of physics, not necessarily due to one single person, as is usually the case. But we could have followed a completely different theoretical or experimental track and never arrived at black holes. We could have convinced ourselves that black holes are impossible and we just stopped looking and we see something like Cus X one. And we say, Oh, well, it's some extreme neutron star that we haven't figured out the physics yet. That's not the case. We discovered black holes, and it was observations in astronomy that led to that discovery. Yes, they were predicted, but yes, they were also debated, and it was observational astronomy that unlocked them.

Number five. We're all stardust, man. If this list seems a little biased to the 20th century, is probably because science itself really ramped up and started moving at an accelerated pace over the past 100 years, aided by significant technological developments. So more science has happened overall in the past 100 years than in the previous 10,000, and for our last one, we have to go back to a very old question. How does the sun stay warm At first, this wasn't much of a question at all. The sun was just warm, the same way that water is wet and that one neighbor is really annoying. This is the way the universe just is. If you think about it for a little bit, maybe it's made of fire or something, I don't know, but there's no need to stress about it. But then, when we invented science and we started stressing about it, Galileo proved that the sun was rotating by observing sunspots. And for the next few 100 years, we didn't make much progress in explaining how it stayed warm. Now that we established that the sun was some physical object with interesting physical characteristics, and we were inventing this science of physics, whose job it was to explain how stuff in the universe worked, that this was a little bit of a problem.

As soon as we invented steam engines and combustion, we immediately guessed that the sun might be burning fuel to release its heat. Lord Kelvin of you know, Calvin fame in the late 19 hundreds made the necessary calculations and concluded with an extreme amount of confidence that the sun and hence likely the entire universe was roughly 100,000 years old, based on its efficiency rate of burning some sort of fuel. This contradicted evidence from geology and biology, which was saying that the Earth was much, much older than that. But considering that astronomy is a far superior science, then obviously this is the correct answer. It wasn't in 1920 Sir Arthur Eddington, guest guest here, based purely on recent developments in subatomic physics, special relativity and quantum mechanics, that nuclear fusion might play a role. But it would take until 1957 for the full picture to come into focus with a paper authored by four people. Margaret Burbridge, her husband, Jeffrey the unrelated William Fowler, who was nicknamed Willie and the man who enjoyed being a thorn in everybody's side.

Sir Fred Hoyle, you know the whole Carl Sagan stick. You know the one. If you want to make an apple pie, you have to start with the Big Bang. We're all stardust. This was that discovery stellar nucleosynthesis, a complete and detailed accounting of how stars through the process of nuclear fusion can lead to the creation of elements. How You can start with a primordial mixture of hydrogen and helium, and from there get carbon, oxygen, silicon, magnesium, iron and then through supernova, get even heavier elements. This was the first time we were able to explain the existence of elements in our universe. Think about how powerful that is, with one very thick, dense paper full of calculations based on observations. Oh, there are so many observations leading to this result because we need to know what stars are made of different chemical mixtures.

We need to put in data based on nuclear reactions like the whole deal synthesized into one paper that describes how elements are made. This picture has been refined and expanded in the decades since, and and this paper did not lead to any Nobel Prizes. And based on my own judging criteria, it did not open up a brand new field of inquiry. Well, it did, but not nearly as large as like black holes or the foundations of science itself. But it did change the way we see the universe as completely and powerfully, if not more so, than Kepler's realization that the heavens obeyed universal laws or Hubble's discovery that the Cosmos is alive with this work. This circle is complete throughout all of scientific history, we've been pushing outwards, exploring more and more of the universe. And in our inquiry into the machinations of the cosmos, we discover something surprising that when we try to explain how stars work, we realize that stars create elements and those elements go on to create new generations of stars, new solar systems, new planets, new US in our journeys.

To understand how stars we work, we inadvertently discover how we were created, that we're a part of the universe and the universe is a part of us. We're connected. What a beautiful epiphany. What a sublime perspective when we look out at the stars, we're looking at our chemical cousins and they're looking back at us. That's it. That's my list. If you disagree with any of my placements, that's fine. But I'm curious to hear what are your top five? Thank you to at that ER guy on Twitter for the question that led to today's episode, and thank you so much to all of my patreon contributors. That's patreon dot com slash PM Sutter big thanks to Justin G, Chris L Barbeque Duncan M, Corey D, Justin Z, Nalla Scott M, Rob H, Justin Lewis M John W, Alexis Gilbert, M Joshua, John S, Thomas de Simon G, Aaron J Jessica and Valerie H For your contributions and thank you to all the people who are constantly asking me questions, I love it.

Send those questions to ask us spaceman at gmail dot com. Check out the website. Ask apace man dot com. Keep them coming and I will see you next time for more complete knowledge of time and space.

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