StarTalk Radio - Time and The Universe, with Charles Liu

Episode Date: September 27, 2024

Can time itself die? Astrophysicist Charles Liu is back in the hosting hot seat alongside comic co-host Chuck Nice to explore black holes, big bangs, our understanding of time and how it relates to the universe. NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free here: https://startalkmedia.com/show/time-and-the-universe-with-charles-liu/x(Originally Aired December 18, 2018) Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. Welcome to StarTalk All-Stars. I'm your All-Star host, Charles Liu. Feel free to call me Chuck. I'm a professor of astrophysics at the College of Staten Island at the City University of New York and an astrophysicist with the American Museum of Natural History. And I am very excited to be here because tonight I have with me my comedic co-host, Chuck Nice. Hey, hey. Hello, Chuck. It's Chuck and Chuck.

You know it. The Chucks. Absolutely. It's great to see you, Chuck. Hey, Chuck. It's always good to see you, man. And I am always, I know that I'm going to have a good time. I'm going to learn something. I'm going to be fascinated. Every time I see your face sitting behind the microphone, I know we're in for a good show.

Oh, you're very sweet. But you know what? I got to tell you, not only are you going to be fascinated today, you're also going to be fascinating. Because you are also our special guest in the studio today. Chuck, welcome Chuck Nice to our wonderful show here. And thank you for being here and talking with us about all the cool things that you do and who you are and all the neat things. Oh, well, thank you for having me. I didn't know this was happening. This is totally fine. Nobody ever wants to know about me. Well, I disagree because I do want to know about you. Really? Yes,

absolutely. You are, I guess, perhaps amongst all comedians, the representative geek median. You're the geek comedian. Geek median. I love that, by the way. You are the man when it comes to representing the humor that comes out of geekdom. And so let's just start right away. Sweet. Today's topic is time. Time. We are talking about time in all of its aspects.

Time cosmologically, time as it exists. As dimension? Yes. And the idea of what's going to happen to us, present, past, and future. And so I'm going to start by asking you, Chuck, what is your take on time? How has time affected your life, your career, your childhood, your adulthood? You know, things like that. Give me a sense of pick a thing that you feel like most exemplifies your interaction with time. So my interaction with time, to be honest, would be mostly philosophical.

Yeah. Believe it or not, it's mostly philosophical. And I found the physics representation of time not too, you know, of course, in high school when you learn about relativity and all that. Right. But I, you know, it was just like, OK, cool. Now we did that. Now I got to move on. Like it was like that, you know, and now I'm fascinated by it. I'm just fascinated by it. But for most of my lifetime has been a philosophical perspective in that it can be a friend, an enemy. It marks the passing of your life mostly. And that my father used to say, there is no such thing as time.

There is only life. Oh, really interesting. Yeah. And so the more you make of your life, the better your relationship with time. And the less you make of your life, the more time seems daunting. Yeah. Seems like an obstacle, right? Yes.

Because time is always moving. Right. And how you perceive it is very different from sort of the cosmic universal clock. the cosmic universal clock. But at the same time, if you are able to live a life that is taking advantage of all the time or that's available to you, then you really feel like you have all the time in the world, don't you? Absolutely. And, you know, it's funny that that happens that way. And so, like, you know, a lot of my life has been spent, you know, pretty much measuring

whether or not I'm – which side of that equation am I on? Like, am I winning at this game? You know, so, and I think that that's pretty common. I think a lot of people actually. I think that's absolutely right. Now, with respect to, you know, science, I think the most fascinating aspect of time, aside from the dimensional aspects of time, okay, aside from that, is really

Einstein's thought experiments. Yes. And the slowing, the physical slowing of time, that to me is just so rich to think that if we could actually travel or approach the speed of light and take a trip and then come back and here I am still 32 years old. No, you're not a day over 29, Chuck. No way. And everybody else is dead. You know what I mean? Or aged.

Like that to me, that's because that is represented in the physical realm. That's right. Okay. That actual thought experiment, if it played out, would be represented in the physical realm. And so, you know, mathematically, you're actually, you found the fountain of youth. Mathematically, you found the fountain of youth. Mathematically, you found the fountain of youth. Like when I think about that, I get really excited for some reason. It really blows my mind. And at the same time, at the same time, excuse me, but simultaneously, as you try to think about the physical slowing of time, my brain cannot do that. Oh, you can. And let me tell you why you can,

because we are introducing a new segment here on StarTalk All Stars. And we will use this segment to illustrate a wide variety of our more complicated concepts of time. The segment is called All Star Super Silly Space Songs. Oh, right on. Okay, and what we're gonna do is- Is it from KTEL? I could ask them if they were interested. Oh, right on. Okay. And what we're going to do is- Is it from K-Tel?

I could ask them if they were interested. That's right. Put it with Teen Rock 67 or something, right? Or Kidz Bop. K-Tel's Kidz Bop and All Star Super Silly Science Songs. Yeah, yeah. That's great. So, yes, our first Super Silly Science Song describes what you're talking about, the dimensional aspect of time. You see, time, as Albert Einstein explained it in his theory of relativity, is a dimension.

It's like space dimensions, like length, width, and height, but it has a unique thing compared to those other dimensions in that it only moves forward. We can't move backwards in time. We can move forward or backward in length or left or right in width or up or down in height, but we cannot go forward and backward in time if we are moving through the universe since the beginning of time, which is the Big Bang. And so all of that together, if you take length, width, height, and time, they come together in this fabric, which we live in, called space-time. And that was what Einstein's tremendous breakthrough was in his general theory of relativity. That we can imagine space and time being knit together, being affected by matter and by densities and things like that.

So we can twist and bend and shape, kind of like an ill-fitting swimsuit made of spandex on the beach. Well, first of all, let me just tell you, that sounds so sexy. Ill-fitting spandex speedos. I believe I've been on that European beach. Oh, my gosh. Don't make me have to unsee what I just saw in my mind. But, yes, the super silly Science song goes something like this. Go ahead.

Okay. And here it is. We thank, by the way, the Rolling Stones for part of this wonderful music, the Super Silly Space song. Well, already I think I know where you're going. Please feel free to join in if you feel like. Okay. It goes like this. It starts like this.

Time is a dimension. Yes it is! Time is a dimension. Yes it is! Okay, do-do time, length, width, and height. Do-do-do-do-do. They all come together. Do-do-do-do-do.

Making space-time. Making space time. Making space time. Making space time. Yes, indeed. Yeah, yeah, yeah. Time, time, time is a dimension. Yes, it is. Well done.

That is the first. There you go. Super Silly Space Song of the show. Super Silly Space Song. Time is a dimension. You know, here's a great thing. So for those of you listening, if you have not seen the StarTalk television show, Chuck is a frequent scientist guest. And inevitably, we break out into song. That's how it should be, right? It is. and inevitably we break out into song. So.

That's how it should be, right? It is. I mean, why does science and song not work together? Song has to do with psychology, it has to do with voice, physics, chemistry of everything. And it's a very, very nice way for us to remember and learn interesting concepts. Very cool.

So that's how we go with that. Nicely done. Oh, thank you very much. Now, I wanted to go right to Cosmic Queries. Okay. Because we have the opportunity today to do a lot of Cosmic Queries, and they've been building up, and thank you all of you who have been making these questions available for us. Let's go right to it. All right, you little curious people. This is John Callahan from Patreon, and he says this. Is the name Big Bang a misnomer? From what I recall, we don't actually have any evidence that the Big Bang started with an explosion like a supernova or a black hole merger. All we know is that the universe began expanding since the beginning

from a very small point, expanding faster during the inflationary period. Yes, that is an excellent question. Thank you for that. And the answer is sort of. The Big Bang is a misnomer if you think of an explosion as a thing that happens in space. Okay? So let's say you have a firework shell. It goes up in space and it explodes. And therefore you have things going outward from its location out into space. Right?

In that sense, the Big Bang is not such a thing because as you say correctly, it is the expansion of space-time. It is literally the beginning of time ticking in the universe. So if we think though more expansively of what an explosion is, instead of just our conception in a typical daily way of an explosion being some sort of chemical reaction. TNT, dynamite type of deal. Yeah. Then you can certainly consider an explosion of space itself from a very tiny, possibly infinitely small point. And then in that case, you can think of the Big Bang as a bang of whatever, space and time, into or just beginning to exist. It doesn't have to go into somewhere.

And that mathematically is still a challenge. You know, what is beyond our universe or what is the Big Bang? But you are completely correct, and I want to thank you for making that point because indeed the Big Bang is an expansion of space-time which has changed speed a few times. Yes.

So that's really, really cool. And in fact, you know what, Chuck? Do you like Big Bang? Do you like the idea of Big Bang? I do, indeed. I like Big Bang. Yeah. I cannot lie.

I like Big Bang and I cannot lie. Oh, you know what? Uh-huh. I like Big Bang and I cannot lie. Oh, you know what? Uh-huh. You are hearing the first line of our next all-star super silly space song. Oh, my God.

Is it I like Big Bang and I cannot lie? I like Big Bang, no, I cannot lie. That's correct. And with thanks to Sir Mix-a-Lot and all that kind of thing. The lyrics here. I can't wait to hear this. No, they have this idea where space starts very small. Yes.

And then space explodes like this big bang, this boom, shall we say. And then there's suddenly room in space, whereas there didn't used to be. Right. And then from that time starts ticking. The big bang is the moment that we start basically time equals zero. Okay. So time starts moving forward. It goes from the past toward the present and into the future, right? So space-time is now very big. The universe expands. And so we just shake from the excitement of knowing that I

like Big Bang. So Chuck, if you'd be willing to help me with this, I will start this song and... Go ahead. Yes, but this is the abbreviated version. There's a lot more, but we'll just keep it short. Okay. So be ready, okay? Alright, I'm ready. Go ahead.

And any of you fellas out there who are listening, you should be ready too. Okay. Alright, here we go. You gotta help me. Go ahead. One, two... I like Big Bang, no I cannot lie. Astronomers cannot deny. The

universe starts as an itty bitty thing. Then space goes boom and then there's room and time starts moving forward. To the present, it moves toward fellas. Fellas. Fellas. Yeah. Does the universe expand? Hell yeah. So shake it. Shake it. Shake it. Shake it. Space time's really big. Baby got banged. All right. Dude, that's crazy. I love it. But that is the Big Bang. By the way.

That is fundamentally what it is. Yes, John. I am really impressed that your lyrics were a spot on explanation. You know what I mean? You didn't sacrifice anything for creative license. You took no creative license. You actually stuck to the astrophysics the entire way through. Look, there's two points that I want to make on that. Number one, there is no reason why strict science, correct science can't be expressed artistically.

There's no need. When you say artistic licenses suggests that I have to stray from what is known scientifically, and I don't because it's there. Okay. So that's great. So thank you for that. But no, it's completely okay. And the second thing I would say to that is that I cannot take credit for these lyrics. In fact, I don't want to take credit for any of these lyrics. I just want to say that a colleague of mine has helped in every instance in creating these. Fantastic.

So can I take credit on my own? It's probably not a good idea for me to do that. But all of my colleagues, everyone who appreciates science has been involved in it. And so I really, really thank everyone for helping. I appreciate your humility. Another cosmic query, sir. Here we go. Let's see.

Paul Foster says, if we could find the point in space at which the Big Bang originated and could also go there, what do you think we would find or learn about the ever-expanding space? An excellent question, Paul. Here's the answer. You are right now at the point where the universe began to expand. Think about it this way. The whole universe did not exist as a spatial entity until the Big Bang happened. Since then, all of space and time has been created. What that means is that we are all in the Big Bang. We are expanding at this moment. Chuck, you know this as

well as I do. You are at the center of your own observable universe. I am at the center of my own observable universe. We are all at the center of the universe and your mother knew that. She certainly did. My mother knew that I was in the center of the universe and you know what? They were both correct. They were both correct. Which is amazing. Now, Chuck, let me ask you this. When you were younger, at an earlier time in your life, at what time in your life would you say that you felt or realized that comedy was your way of moving forward, that the showmanship and so on? And that you – well, we can talk later about the time you decided to bring science into all this as well. Seven, age seven. I was age seven and I had to give a public speaking in front of a large assembly. And I was wearing a clip-on bow tie. I love it. And it fell off.

No. And everybody laughed. And so instead of, you know, I continued to do the thing, but I stopped and picked. Now, what you're supposed to do is just leave it off and keep your speech going. I didn't know that. So I bent down, I picked it up, I put it back on, I kept talking and it fell off. And I did that like eight more times. And then I was like, I like the fact that they're laughing more than I like the speech part. And it didn't bother me. It didn't bother me that I was speaking in front of this big, large group of people and that it

wasn't going well. I just liked the fact that they were laughing. And that was it. I knew at that point that something was there. What a terrific story. Yeah. So really, I mean, it's a lesson to us all who have ever felt a little bit concerned or worried about being embarrassed doing something that didn't happen. Go with the flow. Go with the laugh. Make it part of who you are and own it.

Yeah, I was too stupid to be embarrassed. Or too smart, shall we say. Because now you have been cosmically indoctrinated. This is true. And we very much appreciate that. I'm Nicholas Costella, and I'm a proud supporter of StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson. We want to talk a little bit about time. We've talked a little bit about already the beginning of time, the Big Bang and how time starts going forward. And now we want to talk about how things

evolve, right? The universe. I want to talk about how things evolve, right? The universe. I want to talk about some of the stages of things that happen when time starts, right? After time begins, the universe is very hot. It's very dense, but then it expands and then it starts to cool down because the same amount of energy, a relatively finite, we think, although we're not puzzling sure, amount of energy is being spread out over a larger and larger area. So with that, here's what I want to ask you. Okay. Okay.

So you have this infinitely dense, tiny little spot. Boom. It starts to expand lots of energy, just an incredible amount of energy. That energy is spread over everything that we are now. Why is it then that it was not centralized as opposed to most of space being empty? And then why is it that you have pockets of it like star forming nurseries and things of that nature? Great question. This is what happened, okay? You have to realize, at least based on our understanding, that when the Big Bang happened, space itself expanded. And whatever was in the universe at that time actually was increased

in energy at some future time. In other words, it hasn't happened for a very long time, but we think that there was an influx. If you just count the amount of mass or energy or density that was in the universe at the moment of the Big Bang, it's not enough to fill the universe as it exists today. So something happened, and we think it might have to do with this thing called inflation

or spontaneous symmetry breaking just after the Big Bang, like a billionth of a billionth of a billionth of a second after the Big Bang. Wow. That infused the universe with a really, really large amount of energy. Right. expansion universe to be so rapid for a tiny fraction of a second that that universe, that information was distributed all throughout the universe, almost perfectly uniformly. So now there was enough energy in the universe then for gravity to start to take effect and produce collections of areas that were denser than others. So now here is one of the mysteries involved.

I was about to say that. You've actually introduced a mystery. Yeah. But go ahead. Yeah, you have a circumstance now where we know that there is almost perfect uniformity. Right. But there is a little tiny itty bit of non-uniformity. Right.

Like so small that if, say, we had a sheet of glass, a perfect sheet of glass, the size of the United States, the imperfections from that perfect sheet would be the size of grains of sand or pebbles across this multi-million square mile area. So from there, how did those little tiny kernels of imperfection turn into the planets and the stars and the galaxies, which are very highly concentrated? And the answer appears to be gravity. What happens is that as you pull these things together, gravity doesn't really pull. I mean, gravity does. so for example, black holes don't suck you in. They don't suck you in, right. But black holes or any other objects in the universe that have mass temporarily dimple the space-time around it, causing a little bit of additional stuff to fall into that dimple.

And then the dimple gets larger as more and more stuff falls into it. So that's why you want them – But you'd have to be in the dimple. That's right. In order to fall into it. That's correct. You wouldn't be, if you're outside of the dimple, you just remain outside of the dimple. That's right.

So if you don't fall into, for example, a black hole, then you don't. You're good. You're fine. As long as you stay away, far enough away. Right. It won't suck you in like a Roomba or something like that. Right. Or my ex-girlfriend. Oh, no, no, no, far enough away. Right. It won't suck you in like a Roomba or something like that. Right. Or my ex-girlfriend.

Oh, no, no, no. Terrible relationship. No, I am so sorry. I should have just circled her for years and never gone near her. Sucked me up. That's okay now. I'm happily married for 21 years and everything worked out fine. That's awesome.

Yeah. Let me ask you about that. That's awesome. Yeah. Let me ask you about that. You know, when your family sees you in both the role of a science communicator and as a comedian, how do they reconcile that, say, with the family? So, for example, do your kids like tell people, yeah, my dad's a comedian that tells people that science is cool. My son said that he told somebody, yeah, my dad does science and comedy, which kind of means we shouldn't be eating, but somehow we still are. No, I think you're on the vanguard of a societal shift. I think you're right. I think more and more people. In fact, I think you will eat better than most of us. Well, thank you, sir.

I appreciate that. That's a great, great. But yeah, no, to be able to do funny things, make people laugh in the service of helping people understand our universe around us must be just a really fun thing to do. Well, it is because I love science. I mean, I'm a fan. You know what I mean? I'm just straight up a fan. You know, that's how I feel when I sit with you guys, you know, you guys who are scientists and you've done the work and you have, you know, you have immersed yourself in the discipline that will put that makes you proficient at, you know, disseminating this type of information. I think it's incredible, you like you and every other scientist that is part of our all-stars and Neil and everyone in our universe has spent an inordinate amount of time and money to glean and garner this information.

And then I sit and learn it from you for free. information. And then I sit and learn it from you for free. Well, we owe you a debt too, because by helping people realize that science is something to laugh about and enjoy and revel in, that you're bringing people who may not otherwise have that opportunity closer to the things that we love so much. You know, I mean, you might talk to someone and say, man, sitting eight hours in front of a telescope in the middle of the night trying to get a few photons on a distant galaxy or a supermassive black hole must be so boring. And I said, no, it is incredibly fun. It is at least as much fun as sitting in front of your TV for eight hours playing Super Mario.

See, now that's a great way to look at it. I know a lot of people are going to disagree. Well, that's up to them. However, I've never played Super Mario, so you may be right. To each one's own, way to look at it. I know a lot of people are going to disagree. Well, that's up to them. However, I've never played Super Mario, so you may be right. To each one's own, right? There you go. Okay. So, yeah. Let's go to Cosmic Queries because we've got the creation of the universe and then all the things in the universe that come and form thereafter, right?

Let's talk about the time passing in the universe. So, talking about time passing in the universe, here's a – let me see. This is Frank Mendola. Okay. Says, hey, black holes. In popular movies like Interstellar, they depict an image of a black hole with an event horizon. Yeah. But is that just Hollywood or would there be just a pinched point in space surrounded by gravitational lensing?

Ooh. Look at Frank Mendola. Very sophisticated question. Let me tell you. Thank you. I think you're just showing off, Frank. You're like, let me throw this in here. Let me let everybody know that I don't understand gravitational lensing.

Good for him. But it's a great question. It's a great question. But let's say I don't know what gravitational lensing is. And let's say I don't know what he means by this pinch point. Can you break that down for me? I certainly can. Let's imagine a black hole as basically a structure where the escape velocity from its surface exceeds the speed of light.

Wow. Which means that if there's a light beam that tries to escape from it, let's say you're standing on a black hole and you shine a flashlight. Right. The beam, instead of going off into the sky, will come up and fall down as if you had thrown a basketball or something here on Earth. That is awesome! It's awesome. And that's what makes... That is so cool!

Oh my God, that is so cool! I know, right? And that's what makes black holes black. However, there is... Right. That and they talk like this. I'm sorry. I'm sorry. I'm sorry. Chuck. I'm sorry. Chuck. I'm sorry. I'm just- Hey, where do you think you going?

Hey. What planet do you think you- Chuck. You think you leaving here, planet? Chuck. Get over here. Okay. Okay.

All right. Thank you. Get your ass over here, planet. Chuck. Come on, man. Oh, God. That is so racist and wrong. Oh, please.

And guess what? I don't care. I can do it. I can do it. Okay. Okay, so, that is so racist and wrong. And guess what? I don't care. I can do it. I can do it. Okay. Okay, so I'm sorry. I have made you so uncomfortable. It's okay.

I'm sorry. Go ahead. It's okay. It's all right. I just love that. It's hypothetical. The black, black hole. It's hypothetical.

It's a planet. It's a black hole. Moving on. The black, black hole. I'm sorry. Go ahead. There's got to be a song in that one, too. There is.

I think, you know, black, black hole. Ooh. Well, you know, like Wild, Wild West. Wild, Wild West. The black, black hole. The black, black hole. The black, black hole. Screw you.

Light. Think you're getting out of here light? Okay. All right. Go ahead. Okay. Okay. So you shine it up.

Yes. And it curves right back down. And we just fall back down. Right. So that's all a black hole really is. It curves right back down. It would just fall back down. Escape velocity. That's all a black hole really is.

Now, if the laws of physics as we understand them hold, under what circumstances could such an object exist, right? Right. That's the thing that makes black holes have the structures that they have. Okay. And what we understand now, what we think, is that black holes have a singularity at their center, which has infinite density, zero volume. But around it, out to that point, the event horizon, we call it, where then if you shine the flashlight, it would fall down. What is there? We actually don't know.

So it really depends on the environment of the black hole. If there are no objects in the area, then it would just be a single pinch point. But if there were gas or planets or stars or something like that, they would start to fall in if they fell into that gravitational dimple we described earlier. And then they would start this sort of slow spiral into the black hole. When they reach the horizon, they would fall in. Right. They would never come out. That's their new home. That's it. But if you are sort of in the process of that spiraling in, you can illuminate the edges. You can make the environment bright. Right. It can be very hot. It could shine not just in visible light, but maybe even in ultraviolet or X-rays

or gamma rays. And then the event horizon itself could indeed be this sort of shimmering- An illuminated kind of ring. Illuminated kind of ring just outside the actual limit where things cannot, like photons, light cannot escape. So it really depends. And obviously movie makers will want to make that more brilliant and pretty looking because that's sort of what movies are about. But this talk of black holes leads us to our next all-star super silly space song. Yes, indeed. And it has to do with black holes. And of course that is what we've been talking about, right? Black holes, as we said,

you have to fall into their gravitational dimple in order to fall in. So they don't suck. Black holes don't suck. There you go. But if you fall in one, you're not coming out again. You might as well make a home there. Right. You're not going anywhere.

Objects check in. That's right. But they don't check out. Gotcha. Yes. So this all-star, super silly space song, we thank Harry Belafonte for the tune as we go forward. And please join in at the proper time, okay? Well, I don't know what it is.

You'll see when it comes in. Here we go. The last line. We're just going to do a little bit. Here we go. I'm just waiting. All right, we go. Black holes don't suck.

But if you fall in one, then that's your new home. No, they don't suck. They don't suck. They don't suck. They don't suck. No, they don't. But if you fall in one, then that's your new home. Nice.

There you go. All right. Well done. Thank you, Chuck, as always's your new home. Nice. There you go. Alright, well done. Thank you, Chuck, as always. I like it. Alright, you want to move on to another question? Let's get another Cosmic Query in. Alright, here we go. This is Jonathan Creatitis. Creatitis. Damn it, Johnson.

Johnson. Alright, Jonathan Creatitis. Creat right. Jonathan Critis. Critis. Critis. And, Jonathan, we apologize in advance, but thank you so much. Jonathan, I don't apologize. You should change your name.

You need to change your name, Jonathan. No, I'm joking. I can't. It's Critis. Critis. Okay. It says, if the Big Bang exploded with half the matter. Oh.

Wow. Interesting question. God, these people are, they're on Bang exploded with half the matter. Oh. Wow. Interesting question. God, these people are, they're on top of their self, man. Would galaxies be half this size? That's a great question. Or would there be half as many galaxies? Great question, Jonathan. The answer is that the Big Bang itself, as we said earlier, doesn't contain all of the matter that is currently in the universe.

Right. contain all of the matter that is currently in the universe. Somehow, an injection of tremendous amounts of energy came into the universe after the Big Bang itself. Could have been tiny, tiny period of time after, but it did come in after. So if the Big Bang had half of its matter or whatever it was at the time, it probably would not have affected the universe as it is today. However, that Big Bang might have wound the universe as it is today. However, that big bang might have wound up differently. It might have had different, say, laws of physics associated with it, might have had different things going on. It might not have even gotten big enough to be able to expand and have that hyperinflation that leads to the universe that we have today. So that's a great

question. And the answer is we really don't know, but it won't be an exact half of everything. Right. Okay, cool. And that's what we talked about with those little imperfections and everything like that. That's exactly right. That's fascinating stuff. I love it, don't you? God, it just never gets old.

No, it doesn't. We've been talking this episode about time. Time. And we're heading toward the end of this episode. And thus, it's appropriate to talk about the future, the end of time, the end of things in general. Not necessarily everything, but things do start and then they go on and they come to an end. This is true for stars, planets, galaxies, maybe the entire universe as well. Chuck, tell me, what do you think? I mean, is there an ending?

Is there something coming up that you're looking forward to ending? that you're looking forward to ending? Or was there something that ended at one point in your life that sort of affected you, shaped you, made you who you are, the cool science-communicating comedian guy? Well, I'll tell you that I don't know who that guy is. He's sitting right in front of you. Yeah, I will say that what I do for a living has shaped beginnings and ends.

So every job that I get, and it's kind of sad, because in entertainment, you know that everything you do is ephemeral. There is no stability, longevity. There is no, it's not a job. There's only gigs, as they say. Really? You only can get a gig. You're never going to have a job.

And so it's kind of sad, but this is the way it happens. Every time you get a job, you immediately start thinking, okay, what's going to be my next job? Because this is going to end. Like no matter how long it lasts, this is going to end. Isn't that interesting? And so that really kind of shapes like your entire perspective. Wow. Because you're always looking towards the end of whatever it is that you're doing. Wow. You know?

And so what you have to learn how to do is enjoy it even though you know it's going to end. I see. Yeah, it's weird. But it's a good philosophy, right? If we're always looking forward to tomorrow is going to be, you know, the brass ring or the pot of gold, you may not enjoy the moment. Your perception of time may not quite be the most optimal for your own personal life and enjoyment and satisfaction. Like we were talking in the first segment about, you know, if you like what you're doing, if it's going well, then you have enough time.

Right. Absolutely. And so, yeah, so that's a big deal. Like, you know, you have to be able to always look at it like, well, this will be over, you know, this is done. This is already done. And it's almost like you're looking at what you're doing in retrospect as it approaches. Isn't that interesting? Wow. Well, of course, I'm sure you can take comfort if you don't think about this on a regular basis, that everything that's being talked about now that you and I are talking about is being beamed out into space, all across space and time. So in a sense, although maybe this gig will end, All across space and time. So in a sense, although maybe this gig will end, your message, your information will go on all the way out into the universe over and over again as long as the universe is around.

So how about that for Cosmic Awesomeness? That is awesomeness. And it also makes me feel like I should do a better job. You do just fine, Chuck. And we appreciate you so much. It's been really a lot of fun all these years, really. We've been doing this a long time. We talk about a lot of different things about the universe, and time is just a natural extension of the kind of science that we do and the kind of things that we talk about all the time. Well, I'm certainly glad that I have fallen into your gravitational dimple. I'll say that. Okay. Likewise, sir. Cool. Okay. Let's go to another

cosmic query. You got something? Yes, I do. Why don't we talk about, oh, um, lilac bluets. Okay. Does a star have to be a certain mass to end in a supernova? Why? And which minerals, metals, and others are made? Oh, that's a great question. That is a great question. It turns out that, yes, there does have to be a threshold before it explodes as a supernova is specifically caused when the gravitational pull of a star's core is so strong that it will overcome any external or outward pressure created by nuclear fusion. So, for example, the sun, it has plenty of nuclear fusion and has plenty of gravitational,

the dimple in the center of the sun, like gravitational dimples, quite deep and quite significant. But the structure that forms at the center of the sun, which we call white dwarf or its electron degenerate material, can resist the collapse of the gravitational dimple as the sun's nuclear fusion winds up. But once a star is many times the mass of the sun, it will not be possible. The white dwarf will not support that star's sort of final end stage. And so it collapses down until it transforms into either a neutron star or a black hole. That collapse and transformation is the thing that causes the supernova to occur. So that is the limit. And in terms of elements formed, it can be a wide variety of elements, because in a supernova, you get something called rapid process nucleosynthesis. You have nuclei

that are being bombarded with neutrons, thousands of them sometimes in a fraction of a second. And the combinations of things that can appear are really almost unlimited. Most of whatever shows up, the elements that are built, decay away almost immediately. Within fractions of a second, you might have a uranium-290 or something, but then it decays away. And so then eventually the ones that stick around are the ones that we know, things like uranium-238, for example, or some of the other heavier elements like the gold or the silver, things like that that we're used to. Sweet.

That's very, very interesting. That is. Yes. God, if only you could just do that on purpose. You could make whatever you want. You could. Or just you wouldn't make it. You could make whatever you want. You could. Or just you wouldn't make it. You could mine whatever you want. You have to go really, really far away during the explosion because a supernova will release more energy in 10 seconds than our sun does in 10 billion years.

So you don't want to mess with that. Wow. 10 seconds. Oh, yeah. God, that's cool. All right. Here we go. Wow. Ten seconds. God, that's cool. All right, here we go. How do we predict the whole universe when we what we astronomers have been forced to do is to rely on a few logical assumptions, which may eventually

prove to be false, but currently we still think are likely to be true. Okay. Okay. One is called the cosmological principle, which in a very brief glib sort of way, basically says everywhere is the same. Once you get into large enough scales, if you look at the universe on macro multi-hundred million light year size scales, then statistically speaking, any given volume of that size will be exactly the same as any given volume of the same size somewhere else. So that's a cosmological principle. And the other one we call is the Copernican principle, named after Copernicus. And that kind of, again, glibly in a single sentence might mean we're nothing special.

Copernicus, of course, as we all know, was the person who is credited in European history with dethroning the Earth from the center of the universe and moving it out as a planet among many where the sun became the center. So the idea was, well, Copernicus said that Earth is actually nothing special. We're not the center of anything. We're just another planet. By the same token, our sun is just another star. Our galaxy is just another galaxy. And so in that case, all the laws of physics and things like that are all pretty much the same, no matter where or when we look at the universe. And it is a limitation and all astronomers understand that. But we are comforted by the

fact that just the part of the universe that we can observe is so huge and so vast and so interesting that we'll never run out of things to study and examine nice there you go what a great question yeah there you go okay um yes how about two more we got time for two more okay and and we have one more all-star super silly space song oh well maybe we don't have time for two more let's get the all-star super silly space song. Oh, well, maybe we don't have time for two more. Let's get the all-star super silly space song. Well, go ahead and ask the one more. Let's see if we can try. Ask one more. Okay.

Kiliya Sildes says this. Okay. I can conceptually understand stars, galaxies, et cetera, burning themselves out and undergoing heat death. Yes. But how will time space itself die? Can time die? What a great question.

Here's the deal, right? If the universe were somehow not going to expand forever, then time actually can run backwards. Because time, again, is this, as we've been talking this episode, is a thing that might be thought of in many different ways. One way that cosmologists who study the universe think about it is you can measure time as a rate of expansion of the universe. As the universe gets bigger, that indicates that time is passing. So if the universe were sufficiently dense that the expansion could be stopped and pulled back, then time would die by going back into a tiny little big bang,

like a big crunch, the anti, and then the time line, shall we say, will end there. line, shall we say, will end there. But currently, research suggests that the universe will not collapse upon itself and will expand forever. In fact, it's expanding faster now than it was a few billion years ago. If that trend continues, the universe will get larger and larger. All the material in the universe, unless there's some refreshment, which we don't know anything about, we can't even predict, will become more and more separated and split up. And eventually all the atoms and molecules will disintegrate into subatomic particles and all the black holes and everything like that will disintegrate into subatomic particles. And all we'll have left is just darkness and quiet and cold and calm. Now, in a sense, that is a death of the universe.

That is. But it's a peaceful death. It's not a violent death. Look at that. The universe died in its sleep. Right. It's a calm, gentle ending. And in that sense, this is the time for the all-star super silly space song in this segment. And this is based on, I know many people have sung this before, but we'll thank Boyz II Men for doing this particular one. Talking about the end of time, you know? Look, it'll be quiet, you know, it'll be dark, so there won't be any light. But it's a long, long, long time from now.

At least, you know, 10 to the 100 years from now. So you have no problem with that. It's going to be peaceful. It'll feel like just a long, gentle night. So it's going to be fun. I'm not afraid of it all. I think it's going to be a really cool thing. Yeah, I'm not afraid of it either.

Seeing that it's going to happen 45 billion years from now. Minimum. Minimum. Way, way, way longer than that. Okay. So at the end of time. So you can join in at the appropriate time Okay, let me see

At the end there I don't know, this might be a hard song Or just give me a little rhythm Whatever you want to do I'm scared No, don't be scared Okay Don't be scared

Ready At the end of time It will be quiet there'll be no light in a long long while from now it will be peaceful all through the night

at the end of time at the end of time. Wow, wow, wow, wow. At the end of the time. Nice. I don't know how that was voiced to men, but cool. Well. I thought you were going to end of the road, although we go to the end of the road. Oh, the road.

I thought we were going there. Oh, that would be possible, too. But it was still the night until the end of the road. I thought we were going there. Oh, that would be possible too. But it was still the night until the end of the time. Look, that's going to be the all-star super silly space song for another time. For another time. Because for us, although time continues, the time for this episode has come to an end. Chuck Nice, thank you so much for being both our comedic co-host and our special guest today on StarTalk All Stars. Thank you so much. I am Charles Liu, or you can call me Chuck. It has been a pleasure today. Thank you all so much. You have been listening to StarTalk All Stars. I have been

your host. And remember, stay curious and enjoy the universe. Bye.