Is dark energy a fudge factor?

23:54And by measuring how their brightness changes, you can tell what their brightness actually is. And then you can, from that determine how far away they are. So she came up with this method and then Hubble used it and discovered that, oh my gosh, there's a bunch of stuff in the sky that's not even in our galaxy. It looks like it is because it's sort of mixed up there in the sky, but it's actually really, really far away. And that was the first observation that there's stuff outside our galaxy. There's more than one galaxy in the universe, right? Mind-blowing realization. At the same time, he discovered those galaxies are redshifted, that they're moving away from us.

24:30So that's when we went from the universe is static to the universe is expanding and everything is moving away from us. That sounds like an exciting time to be alive and be in science. Yeah. And for like 80 years or so, that's how we thought the universe worked. And the big question in cosmology at the time was, is that expansion going to turn around? Is there enough gravity in the universe to pull everything back together to make a big crunch? Or is there not enough driving in the universe and things will slow down, but keep drifting forever, right? Those are the two options, like keep drifting forever and expanding or slow down, turn around and come back to a big crunch.

25:10Oh boy. Existential dread. Yeah. And so to know whether it was going to be like option A, drift forever, or option B, big crunch, they had to make more precise measurements of the really far away stuff to look like further back into the history of the universe and see how those distances have been changing with time to see, does it look like it's going to turn over or does it look like it's just going to keep spreading out? So they developed a new way to measure distances, which are type 1a supernova. These are stars that go supernova. They implode, but they're a special kind of supernova. They're stars that didn't initially go supernova.

25:45They just became white dwarfs. They didn't have enough mass in them to go supernova. but then later they get fed extra stuff from their partners in a binary system and then they go over the threshold and become supernova and because of this particular way that they do it it's very easy to measure from how their light curve goes how bright they actually are and therefore how far away they are so then we got this extra candle that we could use to measure really really far away stuff and then we had much more lever arm on our fits to understand the whole history of expansion. Because Cephids, these variable stars, tell you about closer up stuff.

26:21And type 1 supernova are bright enough to tell you about really far away, really far back in time, longer history. Okay. I think you lost me on the lever arm thing, but then you summarized the point, and I'm with you now. Yeah. Well, the point of the lever arm is just like, you're trying to understand the trend, and you want to be able to predict it. Say, for example, you're looking at like Apple stock, and you want to know, is it going to go up or is it going to go down? If you only have three days of data, it could go anywhere. But if you have like 50 years of data, you can make a more confident prediction.

26:49And so you have a better lever arm. You're like, theories are more constrained. And so in order to predict the future of the universe, we had to look deeper into the past. And this was one of my favorite moments in science. It was around 2001. They made this measurement and they asked the universe, okay, is it scenario A that we're going to expand forever? Or is it scenario B that we're going to come back and do a big crunch? And the universe said, no, it's secret option C. It's something you never considered which is that neither of those things are going to happen. And instead what's happening is that the expansion is accelerating.

27:22Both option A and option B suggest that the expansion was decelerating. Things were slowing down. And the difference was like, is it going to slow down enough to actually go to negative expansion to collapse or just sort of drift out towards slower and slower expansion? But secret option C, which is reality, says, no, the expansion is increasing. It's getting faster and faster every year. And this was mind-blowing. This was a crazy idea. Where were you when you learned this? Because this was in our lifetime, right? Yeah, absolutely. I was in grad school, and I was actually at Berkeley in grad school.

27:58And one of the big teams to do this was at Berkeley. Saul Perlmutter was leading that team, and he was racing against another team in Australia. It was very exciting. New grad students working on that project up at LBL was a big deal. And then, of course, they won the Nobel Prize like five minutes later. So, yeah, it was a big deal at Berkeley at the time. It was exciting. You know, anytime you find a surprise, those are the best moments, you know, because it shocks you. It forces you to upend your understanding, you know, to get rid of the dogma and change the mainstream narrative. The kind of thing that, like, you know, pop-sci misinformation artists are always saying we never want to do.

28:33This is our dream come true. I'm imagining grad student Daniel like taking the whole weekend off, going out into the woods and just staring at the stars with his mind blown for a whole weekend. Yeah. And also being like, why didn't I work on that? Oh, my gosh. I could have won a Nobel Prize in grad school. Whoops. That was the second time I missed a Nobel Prize. I also had the opportunity to go to Caltech and to work on LIGO, the gravitational wave observatory. And I remember visiting and they were like, you should join. It's a really exciting time. And I remember thinking to myself, these guys are crazy.

29:07They're never going to see this. Oh, my gosh. They're going to work forever and see nothing. And boy, was I wrong. Oh, man. All right. So if you want to know which projects are going to win the Nobel Prize, check out projects Daniel turns his nose up at. Exactly. They have a great track record. And so this is a big surprise. This is shocking. Already invites a lot of wonder and speculation about the cause of it, because we're talking about accelerating the whole universe, the amounts of energy required and involved are staggering, right? Absolutely staggering. You need some kind of thing which is going to overwhelm gravity and overwhelm all the other forces.

29:46So this is a big new opportunity to learn about the universe. And before people were like, well, are you really sure you want to like upend our understanding the universe? They're like, let's figure out some other ways to see if this is right. Because what if you misunderstood how supernova go or misunderstood something else, and then that's misleading you, it's confusing you, right? So, what we always love to do in experimental science is find other independent lines of evidence that will either contradict the first ones that tell you like, no, you messed up, that the story's not coherent, or tell you the same story.

30:20Because if you hear the same story from four different ways that aren't related to each other, then it's much more likely that you're hearing the true story. You know, it's like you see elephant poop and you hear elephants and you smell elephants and you see elephant footprints, you probably got an elephant problem. Yeah. It would be nice to also see the elephant, but sometimes you don't get to do that. And so we've done that. We have other ways to know the universe is expanding and accelerating. One of those is something we've talked about in the show a few times.

30:52It's from seeing that the universe used to be a hot, glowing soup of matter and light, and it was really dense. And so you think about sound in space, you think, oh, nobody can hear you scream. But back in the early universe, the universe was dense enough that sound could travel through that soup and actually traveled at nearly half the speed of light. It was really, really dense. And so sound traveled really, really fast. And then you had these oscillations where light pushed matter out, and then gravity pulled it back in, and then it bounces back out. So you get these oscillations, and those create sound waves.

31:28And you can see those sound waves propagating through the early universe plasma, because where things were denser, you later on, like billions of years later, you get more galaxies. And where things were less dense, you get fewer galaxies. And when they go out there and they look at the pattern of galaxies in the universe, they can see these rings, these literal rings in the sky. Those rings are still there because they got frozen in when the universe expanded and the speed of sound dropped. So those sound waves were propagating out, and then they got frozen into the universe, into its structure, when the universe cooled and expanded enough that the protons and electrons combined to become neutral.

32:08So then they were transparent and they weren't getting pushed by the photons anymore, which changed the whole dynamics and then left this imprint. And so we know when that happened. We know how big the universe was when they got frozen in. That's like an absolute measure of something. Here's how big it was when it was created, and then we can see how big it is now, and that gives us a standard candle, like a metric, a ruler. So we can use that to see the history of the expansion of the universe, because we can see it now, we can see it in early days. We can see it six billion years ago. If we look out into the universe, it's like somebody put a meter stick in the early universe and then we watch it grow through time.

32:51And you can just use that to literally measure the expansion of the universe and see it accelerate. That's amazing. Yeah. So at first I thought it was going to be like you get two points of time. You can get that point and then where we are now, but you'd need multiple points of time to be able to say it's accelerating. Exactly. Yeah. But you've got that. So that's amazing. It's very cool. And then there's another one which is super cool, which relies on time. These are like cosmic clocks. The idea is to find galaxies who formed stars a long time ago, because stars kind of evolve in a predictable way.

33:24Older stars look different from younger stars, and we know how long stars last. And so by looking at how blue are the stars and how red are the stars, because blue stars tend to be hotter and brighter and not live as long, and red stars are cooler and dimmer and live longer. So as a population of stars age, they tend to go from having some blue stars to having fewer blue stars. So by measuring how red is this population of stars, you can get a sense for how old it is. So just by looking at a galaxy, you can age it by measuring the redness and the blueness. Now, if you look at two different galaxies at different red shifts, ones that are further away and ones that are closer, then we're seeing clocks at different points in cosmic history.

34:08Awesome. Their stellar populations have different ages. And so you don't need to know the absolute age of either galaxy. You just need to know the change of age, which comes from their change in redshift. And that tells you the rate at which the cosmic redshift is changing with time. So the galaxies sort of act as clocks that let us measure how fast the universe was expanding when their light was emitted. Wow. You repeat this at many different red shifts, as you were saying, and you can trace the expansion history. So neither of these are perfect, and there's questions about both of them. One relies on understanding early universe dynamics.

34:45Another one relies on understanding stellar populations. And there are uncertainties, but the cool thing is that they are different uncertainties. There are questions and things we don't understand that are different in each of those three measurements, but they all paint the same story about the universe's accelerating expansion. So in the same way that like dark matter is not a fudge factor because we have lots of independent evidence for it in all sorts of different ways. People thought of so many different ways to check dark matter. And it almost always comes out with the same story. Like, yes, there's a lot of invisible matter out there.

35:18In this way, we've also checked the expansion of the universe and it tells the same story over and over again, that it's been expanding the whole time. In the very early universe, it was decelerating and about 6 billion years ago, it turned around and started accelerating, which is amazing. Absolutely amazing. Maybe this is too much to ask, given the uncertainties associated with each of the different methods that we use that you mentioned earlier, but do these various methods sort of clock the accelerations and the decelerations at the same rate or similar rates, or is there a lot of variability there?

35:51Yeah, great question. And this is connected to a big puzzle in cosmology right now, which is the Hubble tension, which tells us about the rate of expansion. The Hubble constant, which is not a constant, it's a number that changes in time. Thanks, physicists. I know. And to be fair to the physicists and naming, the Hubble parameter, which tells you the rate of expansion, is changing. But technically, the Hubble constant is just its value now, which is a single number. Okay. The Hubble constant tells you about the rate of expansion, and that changes in time. And so we can measure this in lots of different ways, and we don't see total agreement.

36:27There are things we still have to figure out there. And I think that's a sign of a healthy field because people are constantly coming up with new ways to measure this. And the overall story is the same. We know this expansion. We know that expansion is accelerating. There are differences in those expansion rate measurements in early universe and in late universe. And it requires more complicated theories than some of the simple theories that we'll talk about in a minute. And so whether you expect that expansion to be constant in time or not is a subtlety that you have to address when you build your theory of why this is happening.

37:01But yeah, there's also some fuzziness and disagreement about the measurements themselves. Well, I still think we're very clever apes that we figured out any of these methods of trying to explore what's happening in our universe. I know from this tiny little rock that we basically never left, just by gathering photons that happened to come our way, we figured out this incredible cosmic story that's so much bigger than us. It's amazing what people can do. As Hazel says, you know, science is just like looking around and figuring out what happened. I mean, but that's a profound question. What happened?

37:35Yeah, what happened? Exactly. I love the way she minimizes it. She's like, you know, you're just figuring out what happened. I'm like, yes, what happened to the whole universe? That's right. Or, you know, through the evolution of our species, there's lots of what happened questions that we want to answer. Okay, so you mentioned that there's sort of two different things people are talking about when they mention dark energy. And the first is the fact that the universe expansion is accelerating. So we've talked about that. So let's take a break. And when we come back, we'll dig into this cosmological constant idea.

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41:12And we're back, and we're talking about whether or not dark energy is a fudge factor, and the second thing that people are usually referring to when they say dark energy is this idea of a cosmological constant. Yeah. So, Daniel, what's the cosmological constant? Yeah, so we want to understand how could the universe's expansion be accelerating? What's doing that, right? And there's a really interesting history here, which goes all the way back to the beginning of the story we told about when people thought the universe was static. So Einstein came up with his theory of general relativity, which tells us about space and time and how things pull away from each other or expand also.

41:54And this theory of general relativity, it predates Hubble and Levitt. Their discovery that the universe was expanding, that wouldn't come for a long time, many years after Einstein developed his theory of general relativity. So Einstein was dealing with the assumption that the universe was static. And when he put his theory together, he was like, all right, so mass bends space, the universe is filled with mass, so it should curve space and pull stuff together. And then he thought, hmm, well, why hasn't the universe collapsed, right? Like if space is filled with all this mass, why hasn't it all crunched down?

42:28So his theory essentially predicted the universe should have collapsed already. But he looked out and he said, no, the universe is static, so what's going on? Well, there's another knob in his theory. General relativity tells us that space is bent by mass. And the sort of pop-side level understanding of general relativity tells you like, you can think of the force of gravity as the bending of space. But general relativity is much more than that. Different kinds of energy enter into general relativity in a different way. So for example, if you have internal stored energy, what we call mass, that does bend space and does pull things together effectively, although they're actually in freefall.

43:05But if you have another kind of energy, stored potential energy that just fills space, that actually makes space expand. So general relativity broadly doesn't just pull things together. It can also create expansion. Okay. And he recognized that at the time? Question mark. He knew that at the time. And so he thought, all right, what if I just stick a number into my theory? If I add potential energy to the universe, no explanation, no idea what it's referring to, just a fudge factor, put that in to balance gravity so that the universe is then static. Because that's what he wanted to achieve. He wanted to describe the universe.

43:49He wanted to see if his theory was compatible with the universe. And like, is that a bogus thing to do? No. is just essentially asking, well, what would I have to put into my theory to make it describe the universe as I think it works? And remember, he was working on a false premise. He was trying to describe a static universe because that's what they thought we lived in at the time, but they were wrong. The OG fudge factor. Yeah, exactly. So the OG fudge factor was put in to make general relativity agree with the misunderstanding at the time that the universe was static. The other problem with this fudge factor is that the universe, as he described it, had these two competing things, the cosmological constant pushing out and gravity pushing in.

44:30And for that to give you a static universe, they had to be perfectly balanced. So the universe is like on a knife's edge. It's not stable at all. Somebody like drops an extra raisin in the universe, boom, it collapses. You get a tiny smidge more potential energy, boom, it expands. So it doesn't really make sense as a model of the universe. One more reason to hate raisins. I know. Hold on a second. I love raisins. What are you talking about? You're wrong is what I'm talking about. Yeah, no, raisins and cookies are why I have trust issues. That's only because you think they're chocolate chips and then you're disappointed.

45:06But if you're expecting raisins, then you're like, yum, raisins. No, then I'm mad at whoever thought I would like raisin cookies. They don't know me at all. Well, the answer is to put raisins and chocolate chips into your cookies. Oh, no. Porque no los dos. Because then you've ruined. You've ruined the cookie with the raisins. All right, we've had milk digressions, raisin digressions. We should start a food podcast. So then Hubble and Levitt discover the universe is actually expanding. And this whole point of putting in a cosmological constant to describe a static universe, yeah, that was a mistake.

45:37And Einstein said, okay, I'm going to get rid of the cosmological constant. And instead, I'm just going to assume that the universe is decelerating. It's currently expanding, but it's decelerating. So here we're distinguishing between essentially velocity and acceleration. So think about how your car operates. You can have forward velocity. You're going to 50 miles an hour and you're hitting the brakes. You're decelerating. So you're slowing down. You're still moving forwards, but you're slowing down. That's what Einstein assumed was happening. He said, okay, the universe isn't static. The car is not just sitting on the highway.

46:10It's moving forward and gravity is slowing it down. And so he thought eventually it will crunch, right? That was his supposition. But he didn't need cosmological constant anymore, and he got rid of it. Okay. And this was in response to information he learned in his lifetime. He went from thinking the universe was stable to decelerating. Okay. Yeah. And that's the origin of his comment. I don't know the exact quote, that the cosmological constant was his greatest blunder. You know, that he put it in and then he had to take it out. We all make mistakes. Yeah. Now, 80 years later, we discover, okay, the universe isn't just expanding, it's expanding and accelerating, right?

46:49And so now people are searching for a theoretical reason that might happen. What could accommodate that? Not just that it's accelerating, but that it started accelerating recently, right? That the history is that we were always expanding, but that expansion was decelerating for the first 9 billion years. Gravity was winning. And then around 5 billion years ago, 9 billion years into the history of the universe, it turned around and it went from decelerating to accelerating. So like the car was always moving forward, but it was slowing down the first 9 billion years. And then we went from brake to gas, and now we're accelerating.

47:25We're still moving forward, still expanding, but now that expansion is faster and faster. Somebody was like, would you like a cookie with raisins in it? And you put your foot on the gas to get out of there as fast as you can. The universe is trying to escape raisin cookies. I am driving as fast as possible to the oatmeal cookie factory. No, huge mistake. So I can consume them as quickly as possible. Huge mistake. And so the cosmological constant can actually describe this. It's amazing because the cosmological constant says, look, you got some potential energy to fill space. We don't know what it is yet, but say you have something that fills space with potential energy.

47:59That will cause some expansion. And the amazing thing is that as the universe expands, matter gets more dilute, radiation gets more dilute, right? By which I just mean like you got more space and the same amount of stuff. So the density of matter goes down, which means essentially gravity is decreasing, but potential energy doesn't. It's just built into space. So if you get twice as much space, you get the same density of potential energy everywhere, which means more energy. So as the universe expands, the cosmological constant becomes more and more important because everything else has energy density that's decreasing with expansion, but it's staying constant, which means that it gets a larger and larger fraction.

48:44So expansion leads to more expansion because as time goes on, as the universe expands, the cosmological constant becomes more and more important, which according to the equations of general relativity means more expansion until at some point it starts to win and it's overwhelming everything. And that's what happened 5 billion years ago. So it actually goes to accelerating expansion, a runaway effect. And this predicts that as time goes on, it's just going to get more and more important. We're in a dark energy dominated universe. So my brain is trying to make a connection to Nothar and her there.

49:18Did she play a role in helping us understand this? So she didn't help us understand it, but she helps us understand the implications. Because you're probably remembering that Nother has her amazing theory about conservation laws and symmetries. And there's a connection between whether the laws of physics and space are constant in time and conservation of energy. And she says, if space is not expanding and the laws of physics don't change, actually, if the action is invariant over time, then energy is conserved. Check out our whole podcast episode about action if you want to learn more about that.

49:52But now we know that the action is not invariant, that as time goes on, space is expanding and accelerating. And that's how we know that energy can't actually be conserved in our universe. It shouldn't be conserved in our universe because the symmetry that you would need to get energy to be conserved is broken, right? Space is expanding. The action is not invariant. So that's the connection to Emmy Neuther. Is that what you're asking about? Yeah. And so I guess now I'm trying to connect that to, so as the universe is expanding, you're getting more dark energy being made. Is that the same thing as the cosmological constant or is that like a part of understanding the cosmological constant?

50:31It's a great question because that's the essential piece of this theory that helps us make it work. That as the universe expands, cosmological constant is constant. It's a constant density, right? It does not get diluted. That's the reason that it works. And it's sort of amazing that our theory of general relativity already has a knob in it, which if you crank it up to a certain number, explains perfectly, well, not perfectly, but very, very well, this accelerating expansion of the universe. You don't have to reach for totally crazy new theory of physics, but what you do need is potential energy that fills all of space and doesn't get diluted.

51:10And that's the big mystery. So we've made sort of a step forward by saying like, oh, there's a feature of general relativity, which can create this thing, which we've observed, which we know is happening. But it also kicks the can down the road and invites more questions like, well, what is this potential energy? You just like put it in there. You haven't said what it is. Like potential energy is not just some abstract thing. You know, you can have potential energy stored in a field, for example. Like we know that the Higgs boson is a particle that's an oscillation in a field that's out there.

51:41And one of the most interesting things about the Higgs field, the reason it does what it does, is because it's filled with potential energy, unlike other fields. The photon field and the electron field don't have this kind of potential energy, but the Higgs does. It's potential energy that fills all of space. And you might think, oh, wow, is the Higgs boson field providing the potential energy you need to explain the cosmological constant? Wouldn't that be incredible? If you came out from one direction, you're like, hey, the universe is expanding, and that suggests maybe there's potential energy in all of space.

52:15And you came out from the other direction, you're like, hey, particle physicists have discovered a field that fills all space with potential energy. And you might be like, oh my gosh, am I about to make the best understanding in the history of the universe? And you put these two numbers together and say, do they agree? And the answer is no. And not even to within 10 % or 50%. They're different by 10 to the 120. And so let me guess, this is a project you decided you wanted to be part of because it was destined to not get a Nobel Prize. Oh my gosh. Understanding theoretically the source of dark energy would definitely get somebody the Nobel Prize.

52:50And so we have no explanation, right? We have this mechanism, the cosmological constant, which if you put into general relativity can explain the accelerating expansion of the universe, but we have no idea what the cosmological constant really is. It's just like a first idea. It's a number we put in to make things work. And then we come back and say, well, what could be causing it? And our first idea, all the quantum fields that we know about, definitely is not explaining that. That does not work. We don't have another better idea yet. So is that a fudge factor? I mean, I think it's a little bit of a fuzzy question because it's not a bad fudge factor.

53:28It's not like, hey, we discover the universe is expanding and accelerating and we really want to stick with general relativity. So we're going to do anything to make it work. And we're just going to stick this number in here. We're going to pretend it makes sense, even though it doesn't. Right. That's the like cartoon version of conspiratorial physicists trying to defend general relativity or something. I mean, which makes no sense because in reality, everybody, especially the conspiracy folks out there are trying to disprove Einstein. I get Einstein was wrong emails 10 times a day. So I don't know why they think that like, you know, physicists don't also want to disprove Einstein.

54:02Because then your face would be on all the posters. What would your quote be, Daniel? My quote would be, this is never going to work. Daniel was wrong again. Oh, I'd put that poster up. Good to always be skeptical. And the issues go deeper, right? It's not just that we don't know where this number, the cosmological constant, comes from. We'd love to be able to derive it from first principles to say, oh, the Higgs field, and you calculated it, and here's the potential energy, and here's the number you put in, and it works. We're not there yet. We're nowhere close to there. The other issue is that, as I was saying earlier, even just having a single number, the cosmological constant, doesn't quite work.

54:44Because we see the number you would need changing over time a little bit, like the early universe measurements and the late universe measurements. So it might be that there's two different kinds of expansion happening there. So there's a theory of early dark energy that is another kind of dark energy that turned on early, kicked things off, and then turned off, which maybe explains why we're seeing inconsistent measurements. So there's complexity to this fudge factor. And there's even other people out there with totally different theories. Like a couple of years ago, there was all this excitement because people noticed a correlation between supermassive black holes at the hearts of galaxies and the expansion of the universe and the accelerating expansion.

55:28And so there was thought for a while, like maybe supermassive black holes in the hearts of galaxies are the dark energy. Maybe somehow they are doing this to the universe. And there were some problems with that theory and it sort of went away. But what it shows you is not a field that's out there to convince you of one idea of whether or not it works, but it shows you a group of people being curious about the universe, scratching their heads, being open about what works and what doesn't work, like the big mysteries that we write 10 ,000 PopSci articles about a year, the Hubble constant and all this kind of stuff.

56:00We're open about what's not working, and it's a work in progress. And it's a work in progress that's out there in public. You can see people making progress, people disagreeing about it, people suggesting new ideas. There's no defense of the dogma here. This is just like you're watching it in action. You know, welcome to the forefront of ignorance. This is how science works, right? We're confused about how stuff is happening, and we're trying to figure it out. There are some older questions that we're much less confused about, and we're not very excited about revisiting. Like, is the speed of light constant?

56:35You know, maybe we're wrong about that. I don't know. But it doesn't seem as interesting as other questions that we know we're wrong about, And we have no explanation for like, you know, what is the source of dark energy, theoretically. So that's why some questions get more attention and other questions get less attention because, hey, we're humans and we're driven by our curiosity. And curiosity is frankly subjective and personal and, you know, driven by what gets you excited to get out of bed and spend your day doing science. Yeah. All right. End rant. And this is the process. You know, you do what you can with the information you have.

57:10You try to collect more information so that you can ask more specific and better questions. And sometimes you're going to be wrong. You just always need to be open to that. And you move forward the way you can. Yeah. And, you know, let's also acknowledge that there are structural incentives in science and in every human endeavor for people to defend an idea even after we're clear it's not working. You know, there are people who have an idea and stake their reputation on it. and it was their baby. And when it doesn't look like it's working, they try to make it work and they stick to it. And there are definitely structural incentives for people to not do the right thing.

57:47But people have lots of incentives and they're not always necessarily just gonna follow one set of incentives. There are also incentives to figure out how things work and to be a reasonable human being. And in reality, people's actions are complex and this is not a perfect system. And I don't wanna suggest that science is a pure meritocracy and every idea rises to the top perfectly and that we always work on the most useful thing. Absolutely not. It's a messy political human endeavor, but it's also the best system we've ever had for building knowledge about the universe. So anyway, I was supposed to end my rant a minute ago, but this is the real end.

58:25That's rant part two. But I mean, there's like, you know, different people have different incentives. So if you've got somebody whose incentive is to like not back down, even when it's clear that their theory isn't explaining things as well as they thought, There's an incentive for the like lab at the other university across the ponds to prove you wrong. Or there's the incentive of your grad students who like maybe, you know, when they start their own lab, realize I'd really like to be remembered as someone who was right. And so, you know, maybe they slowly push back against, you know, the ideas of their advisor because they don't want to spend their whole careers on an idea that's wrong.

58:57And so, you know, it's different people have different motivations. And hopefully in the end, science pushes everybody towards the right answer. Mm-hmm. Yeah. And another note for people who have ideas that they're excited about and they can't get the community to engage, you've written grant proposals and they've all been rejected or nobody will read your theory. Remember that resources are limited. In a perfect world, we could give everybody money to investigate the universe, no matter whether their theories were popular or not. But we have limited funding, we have limited time, we have limited attention.

59:32We where to put those resources. And so rather than having like one random YouTuber decide, this is what's most important and everybody else is wasting their time. We have panels, we have consensus, we argue over it, we do it in public so that we try to get as many perspectives as possible. But in the end, yes, we do want to put resources towards the things we think are going to lead to discoveries. And that means investing in the mainstream ideas, not always giving money to everybody out there with a crazy new idea, which may be promising and may even be correct, right? But in the same way that the best screenplays aren't always turned into movies in Hollywood, right?

1:00:12The system isn't perfect because of limited resources. And that's just the unfortunate reality. And the way to fix that is not to burn academia to the ground, but to spend more money to fund more of these ideas further from the mainstream, right? If we instead invest in academia, then we get more crazy blue sky ideas. We can take more risks. Anyway, for the third time, I'll say end rant then. Yeah, yeah, sure. We'll see. We'll see. I should stop saying that. That's right. It's like when you title a document or a grant or a manuscript final version, you are making it certain that there will be a final version two and a final version three.

1:00:53But OK, to try to bottom line, we have this observation that we feel pretty darn confident about because we've seen it using a bunch of different methods. Yes. We're doing our best to explain it. We realize that there's shortcomings in our explanations. We are trying to figure it out. It is an open conversation. And this is one of the big exciting questions in physics that, you know, hopefully we'll figure out in the next generation or two or this generation. And if Daniel thinks the lab is probably not on the right path, those guys and gals are getting a Nobel Prize. That's my backwards seal of approval.

1:01:26Exactly. That's right. All right. Well, thank you, everybody, for going on this journey with us back into history to our understanding of the universe and how the universe evolves and how our understanding of it has evolved to try to predict the future and how our understanding will eventually, we hope, coalesce into a crystal clear picture of the history and future of the universe. Good luck, physicists.

1:01:57Thanks, everybody, for listening. Please go and do us a favor and rate the show on whatever podcast app you're using. It really helps people find us. Daniel and Kelly's Extraordinary Universe is edited by the amazing Matt Kesselman. He really is a wizard. You can also find us online on Blue Sky, Instagram, and XDNKUniverse. Come engage with us. You can email us at questions at danielandkelly.org. We really do want to hear from you. And you can find our website, www.danielandkelly.org, where you'll also find an invitation to join our Discord, where everybody comes and talks about the amazing universe.

1:02:36And we also have the most amazing moderators. This is an iHeart Podcast. Thanks for joining us.

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