Daniel and Kelly’s Extraordinary Universe - How Old Is The Universe?

Episode Date: February 28, 2019

How long has the Universe been cooking, and how do we know? Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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Listen to the new season of Dacius Come Again on the IHeartRadio app, Apple Podcasts, or wherever you get your podcast. I'm Dr. Scott Barry Kaufman, host of the Psychology Podcast. Here's a clip from an upcoming conversation about how to be a better you. When you think about emotion regulation, you're not going to choose an adaptive strategy which is more effortful to use unless you think there's a good outcome. avoidance is easier ignoring is easier denial is easier complex problem solving takes effort listen to the psychology podcast on the iHeart radio app apple podcasts or wherever you get your podcasts Hey, Jorge, I've been meaning to ask you a really important question. Yeah, go ahead. How old are you?

How old am I? Isn't that a rude question? It's a little bit rude, but I want to mask it by saying that I'm interested scientifically. I just want to know, like, how did the Jorge begin? Did you start with a big bang? Well, I'm not sure how my mom would describe it. Am I getting better with age? Is that kind of why you're asking?

Yeah, is Jorge like a fine wine that just gets better and better and more valuable, or sort of like yesterday's banana? I have been working on my earthy bouquet and undertones of cherry and oak. I give you 90 points on the wine scale. Did you think we should focus on bigger topics, perhaps? Yeah, I think asking the age of stuff is a really good way to figure out, like, where it came from, and why it's important, and, you know, where it's going to go

and the whole context of everything. So, yeah, I'm interested in how old you are, but I'm also interested in how old the Earth is or how old the solar system is or how old the galaxy is or even how old is like everything. You want to be rude to everything. Yeah, I want to ask your mom

if she was around during the Big Bang and so she can tell us all about it. Your mom is so old, she witnessed the Big Bang. Hey, look, you're the one who brought your mom into this. Hi, I'm Jorge. And I'm Daniel. I'm about 42 years old. 42 years is the perfect age, actually,

since that's the answer to life, the universe, and everything. Yeah, that's why I brought it up. because, you know, I'm the answer to everything. But I did notice you slyly avoided standing your age. I thought I was starting. Did you think that was sly? I did kind of avoid that, didn't I? Yeah.

Yeah. And now you're doing it again. That's double sly. Oh, my goodness. Can you go for a triple sly? Well, let me tell you from the advanced age of 43, that 42 is a good year. You should enjoy yourself while you're young. You should go out there and, you know, enjoy your fitness and your flexibility.

because when 43 comes around, everything changes. Really? 42's peak life. No, jokes aside for me, every year has been better than the last. So, so far, 43 is the best year I've ever had. Yeah, awesome. Oh, what are we talking about? Oh, this is our podcast. Daniel and Jorge explain the universe.

This is not just us chatting about random stuff. This is our podcast where we try to explain the whole universe to you from front to back, from start to finish. Today's topic. How old is the universe? How long has all of creation been around? This amazing, beautiful, crazy, chaotic mess that we find ourselves in. How long has this party been going on? Yeah.

Are we at the beginning of the party? Is the party ending? We're the best moments of the party in the very early evening, and we've missed it already. Yeah. Is the universe the equivalent of 42, or is it all downhill from here? That's right. Let's hope that like my life, every year in the world, universe just gets better than the last, right? That would be pretty nice. But I think it's a really

important question. It's interesting, not just from a, you know, academic physics point of view, like, can we figure this out? But I think it's one of these great questions that touches on something I think everybody wants to know the answer to, right? Like, how did it all start and where is it going to go? Yeah, it's pretty amazing to imagine not knowing how old you are. Can you imagine not knowing how old you are? That is kind of hard to imagine. I think actually a lot of people in the world used to not know like when they were born or how old they were and their parents would just tell them oh you were born in the summer it was several years ago and you know i think a lot of people don't keep track of their age but you're right for most modern people we know exactly how old

we are and that is a big part of our identity yeah i wonder if you could figure it out like if you if you went into your brain and erased that little bit of neurons that store how old you are if you could piece it together just from your memories i think if you slice my brain open yeah you would find rings and probably be able to count them and figure out how old i It was. Don't recommend doing that at home, by the way, people. Is that where your old bouquet comes from? Yeah, if I was a fine wine, I think I would taste sassy but unpretentious.

Yeah, and I'm a little nerdy. Just a little bit of nerdy. Just a little PhD in physics nerdy, but not overpowering in its undertones, yeah. But yeah, imagine how disorienting it would be not to know how old you are. Absolutely. I guess what I'm trying to say is that it's important. to our identity to know how old we are yeah it is and it's important our identity to know how old like human civilization is like what is our history how long have people been crawling along

this planet how long have people been people right that tells you um you know of something about the context and of your own life and i think even more interesting is how long our lives are compared to how long the world has been around you know like we live a hundred years is that long compared to the lifespan of the earth or in the universe you know like is the The universe 200 years old and I'm going to live 100? Or is it a tiny flicker in this vast, incredibly old universe, right? Yeah. I think that helps us understand whether we mean anything.

Spoiler, we don't. Yeah. Kind of like, where do our lives fit in the history of everything else? Yeah. Yeah. And even more interesting, I think, the unanswerable is not just the question of how long are our lives compared to the history of the universe so far, but how much history is left in the universe, right?

Are we in the very, very beginning stages of the universe? Is the universe a baby or is it middle age, right? We have a whole other podcast about that. So these questions are important, I think. Yeah. I feel like we're going through puberty right now. At least the United States, maybe. Your voice is already pretty low if we're going through puberty or anything.

I'm not going to ask you if you're growing hair in any new places. I don't want to know. Is the universe growing hair in new places? I hear that things are pretty hairy in Mars. Black holes are growing hair. People talk about hairy black holes these days. That's totally a physics topic. Oh, really? Are black holes black-haired or blonde?

Well, that's the question. It's like, how many characteristics can a black hole have? You know, because in a sense, it's just a collection of matter compressed down to a tiny scale. We know black holes can rotate. We know they have mass. And the question is, you know, basically, can they have other attributes? Oh. Okay, so this is a really interesting and important question. How old is the universe? And we were wondering how many people out there know how old the universe is.

Yeah, which is interesting from two points of view. is do people care? Have they spent any time thinking about it? Is it important to people? And two, if they do care, do they know the right answer? Are they operating under completely false pretences for how old the creation is? Yeah, so as usual, Daniel went out there to his university and asked the question, how old do you think the universe is? Here's what people had to say. I think 13 billion years. And do you know how we know that number? I believe we look way out as far as we can and detect the early gases from the universe

and then we extrapolate based on the distance we're looking I think something like that 51 51 years 51 years yeah oh wait wait wait world or universe the universe

universe no the universe It's like $1.2 billion? 2 billion. And do you know how we know the age of the universe? By the Big Bang. Yeah, Big Bang Theory. And looking at how far the stars are, right? 52?

Not the university, the whole universe. Oh, I'm sorry. 1.2 billion? All right. And do you know how we know the age of the universe? How do we measure it? Stars? 6 billion years.

Okay. And do you know how we measure the age of the universe? I'm guessing it has to do with some type of carbon dating materials. I don't know. All right. 10 billion years. 10 billion is that your best guess? It's older than 26 years old.

And do you know how we measure the age of the universe? Any idea? Or how would you figure it out if you had to? I don't know. Gravity ripples or something. I'm a biologist, not a physicist. All right, thanks very much. All right.

A lot of pretty good guesses, right? Yeah, a lot of people guess sort of in the range of billions of years. years, right, which is totally respectable. I think my favorite answer is with the people who misunderstood my question, and they thought I was asking them, how old is the university, which it just turned 50, we had a big party, et cetera. But when they said 50, I didn't really understand they misunderstood. I thought for a moment that they thought the universe was 50 years old,

and I thought, my God, I've met some really young Earth creationists. How do I respond, you know, to keep a straight face? I'm trying to be respectful, you know? Yeah. And then I understood, oh, no, they just. miss her the question. Well, when you're young and you're in college, the university is your universe in a way, right? Yeah, exactly.

That is their whole life. I like the guy who said, I don't know, at least 26 years old, right? Which tells you a little bit how self-centered some college students are. But, you know, everybody gave it their shot. He's like, yeah, the universe was here when I was born, so obviously at least 26 years old. That's right. And maybe that's the only information that matters to that guy. You know, like, who cares?

As long as it was around for me, nothing else is important. Yeah, I guess his universe started 26 years ago. Yeah, exactly. But, you know, he's actually using a strategy to measure the universe which scientists use, which is how old is stuff in the universe. The universe has to be at least as old as that. So while his, you know, focused on himself isn't that helpful in determining the age of the actual universe, he's got a good idea there about how to figure it out.

Oh, how old is the oldest thing that I know about? That should give you at least like a minimum age of the universe. Yeah, exactly. So even though he's a biologist, he sort of invented that strategy on the fly. Well, I think it's important. Let's start, first of all, talking about what it means to ask how old the universe is. Like what does the age, what does the term the age of the universe mean? Yeah, that's right.

That's the kind of answer somebody would give it. They're trying to evade a question, right? How old do you? Well, what do you mean by age? I mean, do you mean moment of conception, moment of birth, right? But there's actually a really good analogy there because human age is a little fuzzy. Like if you're conceived on a certain day and then you're born premature, you know, you are older than you otherwise would have been, right? Whereas if you stayed in your mother's womb

longer, you're technically younger, even though, you know, it doesn't really matter from that point of view. Which is kind of arbitrary, right? Because technically your body and your brain, all your parts started earlier than your birth. Yeah, and we're not taking a position here on you, Wendy's a fetus alive. I was just thinking. And maybe that's why. Maybe that's why we do that. But, you know, actually, I heard that in other cultures, they define age a little differently. Like in the U.S., when you're born, you're zero, right?

And the clock starts then. But in other cultures, when you're born, you're one. And your age increases in the new year. And everybody, like, goes up one year in the new year, where the concept of age is, like, how many years have you been around in? Not exactly how many years since your moment of birth. So the age of the universe is sort of a similar question, right? Like, how do you define the zero-th moment of the universe?

T-equal-0. T-equal-0, yeah. Let's talk about what it means T-quil-0. So what do physicists mean usually when they say T-equals-0? Well, it's not terribly well-defined as the problem. What we can do is we can say we know when now is, and we can walk backwards from now to what we know to be a very hot and dense state in the very early moments of the universe, right?

Like a big primordial hot plasma, which is nasty and wet, and all sorts of stuff was happening, right? Like a baby when it's born. Like a baby, a big, hot, nasty mess. It probably wasn't as loud. I don't know, maybe it was, actually. There was baryon acoustic oscillations, so it could have been a lot of screaming going on.

And we understand that very well. Like we can propagate that forward to get to our universe. We can go backwards. But the problem is that just before that is very fuzzy for us. Like we can't see past that. For those of you who heard our episode about the baby universe, we can't see earlier than like 380,000 years after the Big Bang. And so we don't exactly know what happened then.

And so exactly how to define it is not clear. Like you'd like to say, T equals zero is the Big Bang, right? Yeah. So isn't that what they usually mean? that the universe started with the Big Bang, or we don't know. Right, except that we don't really have a great definition of what the Big Bang is, right? Like, we don't know what was the Big Bang. Was it a singularity that then exploded?

Was it, you know, some weird quantum blob? Was it inflatons? Like, that whole process is still very mysterious to us. So we don't know exactly what happened and exactly how long it took. So what we can do. You just blew my mind a little bit. Yeah. Scientists think T-Equo zero is the moment possibly of the Big Bang.

you're saying it's possibly, like, we don't really know what happened around the time of T-Quil-0. Yeah, and the, I mean, the whole definition of the Big Bang is still a tiny bit fuzzy. Like, some people think the Big Bang is sort of still happening. Like, what was the Big Bang? It was this inflation of a dense amount of matter into a hot primordial gas that was on a macroscopic scale, right? Really fast inflation took less than 10 to the minus 30 seconds. Right. And that ever since then, things have been expanding, but things are still expanding.

they're still inflating. Like, we have dark energy, which is just like a modern day analogy of inflation. So from some point of you, you could say, like, the Big Bang is still banging. So then when do you put T-Equil-0? From the beginning of the Big Bang, like we don't really understand very well

the physics of what happened in the early days. So it's hard to define what T-equal zero is. So you mean we can look back in our history and you get to a point where you can't look beyond. And you just assume that there's some sort of event beyond that, but we can't see. That's right. You don't have records of yourself beyond pictures of you when you were one year old.

You've no idea what you look like before you were one years old. Exactly. And so what you can do is you can extrapolate. You can say, like, well, I know what happened when I went from one to two and two to three and three to four. And I understand the biology of it. So I can extrapolate backwards from one and think about what zero must have been like and when zero was, right? How long it took to get to one, which is really the question. When you were conceived, probably.

Yeah, exactly. But if you suspect that the physics happening down there between zero and one, you know, just after the moments of the Big Bang, were different, were interesting, or maybe not typical of what happened the rest of your life, then there's a lot of uncertainty and how to do that extrapolation, right? You can't just blindly extrapolate. Like what if the physics before I was one years old were totally different, which means I could be older than one year old when I think I'm one year old? Yeah, exactly. And it's not that we think the laws of physics were different, but you know, just different as stuff. was happening, stuff we haven't seen, stuff we haven't had a chance to understand. So, you know, we're extrapolating down, down, down, down, down, down.

But we get to a region where we don't really have a lot of data to extrapolate into. So we're skeptical of that extrapolation. But this is a very technical discussion of like exactly when t-equal zero is. The good news is it doesn't really matter. What do you mean? It doesn't matter. We just talk about how important it was. It doesn't really matter exactly when you define T-Equil-0.

because this uncertainty is a small number compared to the age of the universe. Like, we can extrapolate all the way from now back to, you know, less than a million years after the Big Bang, whatever that was, right? And so there's an uncertainty there of like, you know, a million years, a couple million years, whatever,

for what happened before the part we can extrapolate beyond. But that's a small fraction we think of the age of the universe. So if you want to say, how old is the universe, you can sort of sweep that question under the rug. You can say, well, you know,

how old is it, how far back can we see? And that's really 99.99% of the age of the universe. Oh, I see. So if I said, Daniel, I hear you're 43 years old, plus or minus a million years. You would just sweep that under the rug. I would say, no, that's an accurate statement, Jorge. Correct statement. Oh, that's right.

Technically, you are 43 plus or minus. Plus or minus a million, yeah. More plus than minus, but yeah, exactly. But I think a better analogy would be like, you know, I'm 43 plus or minus. a day, you know, or a second, right? These are details on the scale of the times we're talking about. But, you know, we want our listeners to really understand the nitty-gritty. And so the exact definition of the age of the universe is a little bit fuzzy

because those first few fractions of a second, especially, are not well understood. Okay. So when we say the age of the universe, we really mean how old the universe is since some mysterious thing happened called the Big Bang. That's right. exactly and even deeper right we don't know what happened before that so it's just an arbitrary thing to call that t equal zero right it could have been that before the big bang there was another universe which had like a big bang of its own and a big crunch it's not really a different universe it's just like another cycle and this could have been happening forever so when you talk about the age of the universe you really can only talk about the age since this early state that we understand what happened before that is a total question mark the universe could have just started before that It could have gone on forever before that. Okay, let's get into how we know all this stuff.

But first, let's take a quick break. A foot washed up a shoe with some bones in it. They had no idea who it was. Most everything was burned up pretty good from the fire that not a whole lot was salvageable. These are the coldest of cold cases, but everything is about to change. Every case that is a cold. old case that has DNA. Right now in a backlog will be identified in our lifetime. A small lab in Texas is cracking the code on DNA. Using new scientific tools, they're finding

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I'm Dr. Joy Hardin Bradford. And in session 421 of therapy for black girls, I sit down with Dr. Othia and Billy Shaka to explore how our hair connects to our identity, mental health, and the ways we heal. Because I think hair is a complex language system, right? In terms of it can tell how old you are, your marital status, where you're from, you're a spiritual belief.

But I think with social media, there's like a hyper fixation and observation of our hair, right? That this is sometimes the first thing someone sees when we make a post or a reel is how our hair is styled. We talk about the important role hairstyles play in our community. the pressure to always look put together and how breaking up with perfection can actually free us.

Plus, if you're someone who gets anxious about flying, don't miss session 418 with Dr. Angela Neil Barnett where we dive into managing flight anxiety. Listen to therapy for black girls on the iHeartRadio app, Apple Podcasts, or wherever you get your podcast. Okay, Daniels, so settle this for us. How old do physicists think the universe is? 43 years old.

I mean, that's how long I've been alive, so what else is important? No, the most accurate age of the universe currently is 13.8 billion years. That's how long we think the universe has been expanding since that hot, dense, nasty mess at the very beginning. Okay, and just to put that into perspective, the solar system is 4.5 billion years old. That's right. So the solar system's only been around

for the last third of this party. There was 10 billion years almost when we didn't even have our star, right? Wow. So two-thirds of the universe, there was nothing where we are. Oh, there might have been stuff, right? There might have been other stars.

There might have been globular clusters or gas or whatever. But our star took 10 billion years to even form. Wow. Okay, and by that, by the same account, the Earth itself is about 4 billion years old. That's right, yeah. It took less than a billion years for life to start on Earth.

Wow. Yeah, and then to put that in scale, my Fablius University, UC Irvine, is 50 years old, right? So now the party has started. Well, the United States is only about, it always blows my mind a little bit. The United States, it's only like 250 years old, less than 250 years old.

I know. My brother keeps reminding me of that because his university is like three times as old as I. country, right? He's at Oxford. So, you know, they have traditions. They have like, I have silverware over there that's older than our country. So he's, he's a younger brother and he's like trying to find something to get to have over you. Aren't always, aren't younger brothers always doing that. No, he is an academic rock star at Oxford. And so he gets to look down on the rest of us at fairly new universities.

Okay, so 13.8 billion years old. That's how old the universe we think it is. And how do we know that? How do we know? Are there, is there a birth certificate? Is there like DNA evidence? Well, I've been asking your mom, but she claims did not been around then. So we have to figure it out for ourselves. There's basically two ways that we, we know the age of the universe. And this is really classic science strategy, is like find two completely separate, independent ways of asking the same question. And then if they agree, then awesome, you think probably you have it figured out. And if they don't agree, then you know something's wrong. Like to independent then experts.

Yeah. Or two suspects more like. Like if you're a detective, you're trying to figure out, you know, who did something, you find two suspects, you separate them, you ask them questions separately. If they tell you all the same details, they're probably telling the truth, right? If they give you totally different stories, then you know they're lying. So science is sort of like that. Okay.

So what's the first way that we know how old the universe is? The first way is just looking for old stuff. Like if you find something in the universe that's 50 billion years old, then you know the universe is at least 50 billion years old. right it's not very complicated so you just look around and you try to figure out how old is the stuff around us and that sets like sort of a lower limit on the age of the universe so if you find a rock that's 60 billion years old then you know the universe must be at least 60 billion years old that's right yeah or if you find an unpaid bill from 14 billion years ago right then you know

you know your universe is about to end that's right you know exactly they're coming for you Yeah, but that's a tricky thing to do, right? How do you know the age of stuff, right? We've changed one question. How do you know the age of the universe into another question, which is how do you know the age of stuff we see around us, right? Yeah, well, what's the oldest stuff that we know about then? Yeah, the oldest stuff that we know about is stars, basically.

I mean, there's a caveat there with the cosmic microwave background, which we know is a little bit older, but that's more difficult to age. But direct stuff that we can see, that we can ask the question, How old is it, are stars? And we look around and we look for really, really old stars. And this is a tricky thing to do, but what you can do is you can look for blobs of stars. They're called globular clusters. These are collections of stars.

They're sort of like mini galaxies. I mean, they have a whole different name for them because of the size distinction, but they're called globular clusters. He didn't like mini galaxies? Galaxinos. I thought that would have been good. Galaxini's. Yeah, exactly. That sounds like a nice pasta.

I'll have the Galaxini's with anchovies, please. Yeah, so you look at these globular clusters, and you ask, how old are they? How old are the stars in these globular clusters? And it's hard to know how old an individual star is, but you can look at a group of them, and you can figure out how old that group is. Really? Yeah, based on which ones are still there and which ones are not there anymore. And the reason is that stars have different lifespans, right?

So you form a bunch of stars, and they form out of gas. in dust they coalesce with gravity and you get some really big ones and you get some really little ones now the big ones burn really fast and they don't last very long and the little ones they burn a long time they're like saving their fuel remember stars burn by compressing hydrogen right and they glow and they burn it's fusion and you can listen to our podcast episode about that if you're curious about that but the big ones burn out pretty quickly so if you're looking at a population of stars really really far away and you notice that they still have a bunch of big ones in them you know it's pretty young because those ones would have burned out already if it was old like the cluster itself is young

like the cluster itself is young exactly and if you find a club a group of stars the globular cluster that only has little stars in it left then you know it's pretty old because there's been time for all the bigger stars to burn out okay so what's the oldest star that we know about or how old are the oldest stars that we know about well this is really fascinating it's been controversial because this is a hard thing to do you have to know how far these things are away you have to have to measure their light. There's a connection between the color of the star and its size. So it's a lot of intermediate steps, right? You see the color that tells you the size, that you can make a distribution of the sizes. There's a lot of steps that go along, and there's a lot

of uncertainty. And things happen very quickly in the beginning of a life cycle of a globular cluster, like the big bright stars burn out fast. Near the end, things happen more slowly, which means for really old stuff, the uncertainties are pretty large. Like, it's hard to tell the difference between a 10 billion-year-old globular cluster and an 11 billion-year-old. But between 1 and 2 billion is easier. So people have been looking at these things for a while, and the oldest ones we found are something like 13 billion years old. That's a very recent estimate. Up to like 20 years ago, people thought they had found globular clusters that were like 20 billion years old or even 30 billion years old. Did you say 30? 30, yeah. They think maybe the universe is 30 billion years old.

Well, that's what they thought for a while. They had this one measurement from the stars that was saying like 20 or 30 billion years old. And they thought, well, let's compare that to other ways we can measure the age of the universe. Now, the most current one, in the end, they found some mistakes and they updated it. And they weren't like, you know, somebody goofed by adding one plus one making three. You know, we just got a better understanding of how stars evolve and how they burn and how to do these calibrations. And now the more recent updates are like 13 billion years old. But for a while, it seemed like those globular clusters were suggesting the universe was older than 20 billion years.

So there are things out there in the universe that were there when the universe started that are still around today? Well, not quite when the universe started, right? We're looking at stars. And, you know, the universe started. There was the big bang. There was a hot mess of plasma. The thing spread out and cooled off. And then stars formed from that gas and dust.

Those are called the first generation stars. None of those stars are still around. We can't see those stars. nobody's ever seen those we're looking for them it's people want to understand it but nobody's seen those the OG stars the OG stars exactly back when stars were cool man back when they were hot in the 90s yeah and then those didn't last very long and then they you know they burn they cool they exploded supernovas and you have this they gather back together you have the second generation of stars so remember stars are this cycle right they burn they then they explode and their fuel get spread out into the

universe then they gather back together make another cycle And so the second or third generation, it's sort of the oldest stars that we can see so far. And that's why it's a lower limit, right? We see something super old. We don't know if the universe is old, how much older than that the universe is. We just know it's at least that old. It's like finding a relic from an ancient civilization. You know that the civilization is at least at all, but it could have been around for much longer.

Just because you haven't found something older, it doesn't mean that it wasn't older. That's right. Exactly. It sets a lower limit. And currently that lower limit is about 13 billion. years old. That's the oldest thing that we've found. So we're seeing things from the very, very early universe, not exactly from

the beginning, right, but from very, very early on, which is pretty awesome, right? That's like the ancient history of the universe. I think that's super cool. Yeah. Imagine like coming up to these clusters and you're staring at something that's been around for 13 billion years old. Yeah. That'd be pretty amazing.

Yeah, well, I mean, I'm already just flabbergasted looking down at the earth, right? The earth has been around for 5 billion years. It's such an ancient rock. seen so much history. I think about that when I, you know, we just walk across the planet. I wonder, like, who else has stepped here? That's one of the things that makes me love those footprints, right? You can see like footprints of dinosaurs from hundreds of millions of years ago. Like, they were just like walking along, boop. You know, so much has happened on this

planet we're not even aware of. There's so much history that's just been lost that we'll never know. Okay, so that's one way we know how old D universe is. What's the other way we know? The other way is by looking at the expansion of the universe. We know that the universe is spreading out. Things are moving away from us, and they're moving away from us faster and faster every year. And we can measure that.

We look out in the universe and we see how fast things are moving away from us. We can measure that by looking at how the light from them is stretched. Things that are moving away from you have their light waves stretched out longer. They turn more red. Things that are moving towards you have their light waves squeezed. They turn more blue. This is the Doppler effect. It's the same effect that makes like a police siren sound different as it's approaching you and leaving you, right?

So we can use that to measure how fast things are moving away from us. And if you remember our podcast episode about dark energy and the expansion of the universe, we have these really cool standard candles. They're called Supernova, Type 1A Supernova, and we know how bright they should be, and we can look at them, we can measure their velocity, we know how far away they are. So we use that to measure how fast the universe is expanding. That's important because remember we talked about the definition of the start was really what we're doing when we're measuring the age of the universe is we're saying

how long has the universe been expanding since that hot date? And if you know the expansion rate, then you can extrapolate backwards. So we hit the rewind button from how fast we think the universe is expanding and that makes the universe, if you watch it in reverse, makes the universe go down, down, down, down, down into a very small blob. Yeah, exactly. Everybody starts talking funny because it's backwards. Yeah. And the critical thing is you have to measure the rate, right?

We have to know the expansion rate to know how fast to rewind. And we have to know the expansion rate now and the expansion rate a billion years ago and 10 billion years ago. And we can do all that because remember, the further we look out into space, the further we're looking back into history. Right. So we can see the expansion rate now. We can see it a while ago. We can see it a long time ago. Like the history of the universe is written out there.

in the stars. Like you can tell how fast things we're expanding throughout the history of the universe. Yeah. And our history is out there also. You know, light left the earth when you were 10 and you did something embarrassing at your cousin's birthday party. Light from that event left the earth

and is still out there and somebody could capture it and see that, right, even though it happened 20, 30, 40 years ago. So all that information is still out there. Yeah. So watch out. So watch out. It's an alien light that come back and expose your 10-year-old antics.

that's right well when the aliens come they'll have seen it right so they'll know who's been naughty and who's been nice santa is an alien what oh did i just reveal that on the air oops yes santa is an alien i mean santa can do a whole bunch of stuff that nobody else can do right i think having him be an alien with super tech is really the only reasonable explanation that would explain it yeah that myth yeah boom we just solved that mystery right there well this is a perfect point to take a break A foot washed up a shoe with some bones in it. They had no idea who it was. Most everything was burned up pretty good from the fire that not a whole lot was salvageable.

These are the coldest of cold cases, but everything is about to change. Every case that is a cold case that has DNA. Right now in a backlog will be identified in our lifetime. A small lab in Texas is cracking the code on DNA, using new, scientific tools, they're finding clues in evidence so tiny, you might just miss it. He never thought he was going to get caught. And I just looked at my computer screen. I was just like, ah, gotcha. On America's Crime Lab, we'll learn about victims and survivors. And you'll meet the team behind the scenes at Othrum, the Houston Lab that takes on the most hopeless cases to finally

solve the unsolvable. Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Hola, it's Honey German, and my podcast, Grasas Come Again, is back. This season, we're going even deeper into the world of music and entertainment with raw and honest conversations with some of your favorite Latin artists and celebrities.

You didn't have to audition? No, I didn't audition. I haven't audition in, like, over 25 years. Oh, wow. That's a real G-talk right there. Oh, yeah. We've got some of the biggest actors, musicians, content creators, and culture shifters

sharing their real stories of failure. and success. You were destined to be a start. We talk all about what's viral and trending with a little bit of chisement, a lot of laughs, and those amazing vivas you've come to expect. And of course, we'll explore deeper topics dealing with identity, struggles,

and all the issues affecting our Latin community. You feel like you get a little whitewash because you have to do the code switching? I won't say whitewash because at the end of the day, you know, I'm me. Yeah? But the whole pretending and code, you know, it takes a total.

Listen to the new season of Grasasas Come Again as part of My Cultura Podcast Network on the IHartRadio app, Apple Podcasts, or wherever you get your podcast. I'm Dr. Joy Hardin-Bradford. And in session 421 of Therapy for Black Girls, I sit down with Dr. Othia and Billy Shaka to explore how our hair connects to our identity, mental health, and the ways we heal. Because I think hair is a complex language system, right? In terms of it can tell how old you are, your marital status, where you're from. you're a spiritual belief.

But I think with social media, there's like a hyper fixation and observation of our hair, right? That this is sometimes the first thing someone sees when we make a post or a reel. It's how our hair is styled. You talk about the important role hairstylists play in our community,

the pressure to always look put together, and how breaking up with perfection can actually free us. Plus, if you're someone who gets anxious about flying, don't miss session 418 with Dr. Angela Neil Barnett. where we dive into managing flight anxiety. Listen to therapy for black girls on the IHeartRadio app,

Apple Podcasts, or wherever you get your podcast. So if you know the expansion rate, the universe you can rewind back. And we actually measure the expansion rate two different ways. One is just by looking at how things are moving, right? Right. Right. these stars. The other is by looking at the cosmic microwave background. This is the light from

the very early moments of the universe. That also tells us how old the universe is? Yeah, it contains an incredible amount of information about what was going on in the early universe, how much dark matter there was, how much normal matter there was, how dense it was, all of that stuff. And all that information in the end can tell you about the expansion rate of the universe. But you can extract the expansion rate directly from that. That's actually the most precise way to do it. And then once you know the expansion rate, you can rewind the universe to figure out how old it is. And that's the measurement that tells us it's 13.8 billion years. And the uncertainty on that is about 21 million years. So it's pretty accurate. Plus or minus 21 million years. Depends in

your scale. Yeah. But it's kind of interesting that, you know, scientists hit the rewind button, right? We look out into the stars. We hit, we press the rewind button. We see it all compress. And then we sort of stop once it gets really small, right? Because we, A, we can't rewind further, but also kind of conceptually, right? We can't imagine there being anything before that, or we can't imagine anything surviving being that small. Yeah, and we have to ask questions like, what does it even mean, you know, space and time started at the Big Bang, so can you count before the Big Bang? You get into really, really difficult philosophical waters, absolutely. And, you know, it's only recently that we've known this. This seems to be an important piece of information. It

tells me something about who I am and how to live my life and how meaningless it is. But it's sort of a new piece of information. You know, like a hundred years ago, people thought the universe was steady state, right? That there was just a bunch of stars out there. And they'd basically always been there. And the universe wasn't expanding or contracting. It didn't have an interesting history or a moment of birth. It was just been around forever. Right. This was a hundred years ago, right? Only. Yeah, only 100 years ago. So for most of human history. First of all, for most of human history, we didn't understand anything about anything, right? So we were basically completely all ignoramus. You just

exalted most of humanity, but go ahead. I mean, in the best possible way. But yeah, and only about 100 years ago, do we even figure out that there might have been a beginning, that there was this expansion which suggests, you know, that if you rewound it, you got back to a very early, hot, nasty state. So 100 years ago, we thought the universe had been around forever, right? Yeah. Like forever, infinity, right? Yeah, so what was that like to learn that the universe,

you know, to go from age of the universe is infinity to age is, you know, in the billions of years? And it wasn't until the 50s that we had any sort of accurate estimate, because these things are hard to measure. It's taken decades to get the technology and the math and the physics models. So it was in the 50s that really had the first accurate estimate of the universe's age at about 14 billion years. Wow.

Okay, so the universe is 13.8 billion years old, plus or minus 21 million years old. And so what does that mean? What does that tell us about how the universe came to be or where it's all going? It tells us something about how far we are along. You know, we know that we've been around for long enough for galaxies to form, right, for galaxies to spin for a while, for stars to form and explode and coalesce again and form and explode, right? We're not in the very first few moments of the universe, but we don't really know much more than that. Yeah, and more important, we don't even know how old the universe is going to

be, right? We don't know how all the universe is going to be around. So we could be in the very early part of the universe, or we could be in the really late part of the universe. We don't really know. No, we have no idea, exactly. It could be that in a trillion years, there are life forms that are studying the age of the universe, and they think about this first little bit, the first 15 billion years as like the big bang right to them this could have just been like oh the engine's just getting started you know put put put put put put form from stars and galaxies we don't know and we don't know if this part of the age of the universe is typical right like it could be that things go along and everything turns to black holes and they have like only black holes for a trillion years right um so we

really don't know wow when is the puberty of the universe right things changing or is it already grown up we don't know so maybe the real question we should be asking the one that that's less rude, is how young the universe is. How young is the universe? Exactly. Hey, universe, how do you feel? You know, you're feeling pretty good, yeah? Got some joint pain.

You've been planning for your retirement? Yeah. You know, like if you knew you were going to live to a thousand years old, you would say things like, oh, I'm only 42 years young instead of 42 years old. That's right. If I knew I was going to live to a thousand, I would have started saving for retirement a lot earlier. You want to be retired for 9,000, 9,000. 160 years.

No, honestly, I'm never going to retire. I mean, I have tenure. Why should I ever retire? I'm going to sit in my office for the next thousand years and do physics. You're already retired. Mentally, mentally retired. No, you do your best work and you have tenure. That's exactly the point.

You're free to think and expand and go to crazy places in your career, like recording a podcast with a cartoonist, right? Yeah, sure. Yeah, and the universe is 50 years old. The universe is 50 years young. all right everyone so that's the answer to the question how old is the universe and how do we know or how young is the universe how young isn't the universe oh my god universe you look good you're looking sparkly that's right keep burning bright universe we're happy to be around

see you next time thanks for tuning in if you still have a question after listening to all these explanations, please drop us a line. We'd love to hear from you. You can find us at Facebook, Twitter, and Instagram at Daniel and Jorge, that's one word, or email us at Feedback at Danielandhorpe.com. I'm Dr. Scott Barry Kaufman, host of the Psychology Podcast. Here's a clip from an upcoming conversation about how to be a better you. When you think about emotion regulation, you're not going to choose

an adaptive strategy which is more effortful to use unless you think there's a good outcome. Avoidance is easier. Ignoring is easier. Denials easier. Complex problem solving takes effort. Listen to the psychology podcast on the iHeart Radio app, Apple Podcasts

or wherever you get your podcasts. Hi, it's Honey German and I'm back with season two of my podcast. Grazias. Come again. We got you when it comes to the latest in music and entertainment with interviews with some of your favorite Latin artists and celebrities. You didn't have to audition? No, I didn't audition.

I haven't auditioned in, like, over 25 years. Oh, wow. That's a real G-talk right there. Oh, yeah. We'll talk about all that's viral and trending with a little bit of cheesement and a whole lot of laughs. And, of course, the great bevras you've come to expect. Listen to the new season of Dacias Come Again

on the IHeart Radio app, Apple Podcast, or wherever you get your podcast. Every case that is a cold case that has DNA right now in a backlog will be identified in our lifetime. On the new podcast, America's Crime Lab, every case has a story to tell, and the DNA holds the truth. He never thought he was going to get caught, and I just looked at my computer screen. I was just like, ah, gotcha. This technology's already solving so many cases. Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. This is an IHeart podcast.