Deep Time: The Cosmos and Us

Deep Time: The Cosmos and Us

Photo illustration/logo by Mark Riechers/Midjourney/Firefly. Original images via NASA, ESA, and S. Beckwith (STScI) and the HUDF Team (CC-BY)

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Original Air Date: 
November 18, 2023

Our lives are so rushed, so busy. Always on the clock. Counting the hours, minutes, seconds. Have you ever stopped to wonder: what are you counting? What is this thing, that’s all around us, invisible, inescapable, always running out? What is time?


Time may be a fundamental quality of the universe, but physicists still can't explain what time is. That hasn't stopped theoretical physicist Marcelo Gleiser from devoting much of his life to studying the origins of time and the formation of the cosmos.


Marjolijn van Heemstra is the poet laureate of Amsterdam. As her anxiety about climate change and other problems ratcheted up, she found solace in the larger cosmos and became a "dark sky" activist.


Physicist Carlo Rovelli travels to the core of a black hole, where the arrow of time reverses and a white hole is born.   


Show Details 📻
November 18, 2023
Theoretical physicist and Professor
Full Transcript 📄

- [Anne] It is To The Best Of Our Knowledge. I'm Anne Strainchamps. Something about living through the pandemic shifted my awareness of time. This was back when we were starting working from home and my days were a lot less rigidly structured. After a while, clocks kind of receded and in their place something else opened up this deep curiosity about time itself. I mean, I could count down the seconds in a minute, but I can't explain what I just measured. What is time? I decided to ask my friend, Marcelo. Marcelo, I don't understand what time is.

- [Marcelo] Hmm. Well, good. You're in very good company.

- [Anne] He's a theoretical physicist.

- [Marcelo] Time is completely embedded in our existence and who we are, and yet we don't know what it is. We can give you operational definitions of time. Physicists are very good at that, but that does not mean we know what time is.

- [Anne] Okay, that is not what I was expecting. I mean, Marcelo Gleiser works in cosmology and high energy physics at Dartmouth College. He won the 2019 Templeton Prize. He's written seven books about time, space, the big bang, the origins of everything. Let's try again. You know the analogy people use about the fish and the ocean and the fish can't tell it's in water because it's in water? Maybe time is like that?

- [Marcelo] Yeah, perhaps you should not be asking what time is because time is just a construction that we humans created-

- [Anne] Huh.

- [Marcelo] To make sense of the fact that we are born, we live, and eventually we don't anymore.

- [Anne] But are you saying time is a kind of fiction, then?

- [Marcelo] It's not a fiction in a sense of we made it up, but I don't think it is a thing, as a glass of water is a thing.

- [Anne] Is it a force, like gravity?

- [Marcelo] I don't think it's a force either, because... From a very basic perspective in physics, time is a way of measuring change.

- [Anne] I'm not sure I'm buying this either.

- [Marcelo] So let me explain. If you're in a room and nothing happens, you don't need to describe anything. You don't need time. You only need time when it's telling a story, a story of how things change.

- [Anne] So any change you need to define in time.

- [Marcelo] Yes.

- [Anne] Okay, this actually makes sense to me. As a journalist, I do know that the one thing you need to tell a story is change. Without change, there's no action, no plot, no life.

- [Marcelo] So for example, paradise, let's talk about religion a little bit. So, what is paradise? Well, paradise is a timeless realm, right? Everything is eternal and things don't really change. Everything is about the same. And that to me is the fiction.

- [Anne] So what if we thought about time as a story? The story of the universe? This is episode three of Deep Time, a new series from To The Best Of Our Knowledge. This hour, what is time? Okay, how are you? Good to see you.

- [Carrie] I'm well, thanks. How are you?

- [Anne] I'm good. How was your time in Italy?

- [Carrie] It's magical.

- [Anne] Aww... It's a sunny morning in early September when I stop at Marcelo Gleiser's house near Dartmouth. Yeah, we would've traded some of our rain for some of your heat.

- [Carrie] Yeah, I know, it was too...

- [Anne] It's gonna be a hot day. His wife Carrie, is heading out for a run. That's good, do it before it gets too hot.

- [Carrie] Yeah, exactly.

- [Marcelo] Yeah, I wanted to do that too. But, later.

- [Anne] I wanted to visit Marcelo because I know he's thought a lot about time. Professionally. As a world class theoretical physicist, and also personally as someone who lived through a devastating loss in childhood and has been struggling to understand the nature of time ever since.

- [Marcelo] We humans are completely bound by time, right? We have a bracket of existence, and that is the reason for the biggest anxiety you can have as a human, but it's also the biggest inspiration for creating, for trying to transcend this boundary of time. So a lot of what we do in the arts, being a scientist, being a mom, being a grandmother with recipes that go from generation to generation, is that we are trying to stay. We try to find ways of remaining, because you are only really dead when nobody remembers you existed, you know? So if you go backwards in generations and say, I remember my parents really well. I remember my grandparents really well. What about my great-grandparents? Poof. Void. They existed. They had a whole life. They had a whole purpose of being, but we don't know anything about them. And that's just horrifying to many people. It should be.

- [Anne] Yeah. I think that the stories that we tell about time are imbued with, connected to sorrow and grief, for the reasons you said. Time ends all things. I mean, you've said you had an early tragic recognition of that. Your mother died when you were very young.

- [Marcelo] Yeah, so I was thinking when you said that, there is definitely this connection of time and loss, but it's also time and gain, it's light and shadow here. And yes, when my mother died, I was six, and it was a time of darkness in my life. You know, how could that even happen? You have no understanding of what that means. You just have the void, the emotional void of not having a mom. And then all your friends have moms and their moms come pick them up at the school, you know, and hold their hands. And I didn't have that. So my dad sometimes came, but he was a busy man.

- [Anne] Did you start thinking about some of these larger questions, time, where do things go, where do things come from, in the wake of your mother's death? Do you think that that helped shape you as somebody who was drawn to those questions?

- [Marcelo] Yes, absolutely. I have no doubt. You know, because a life that is interrupted at 38 in a tragic way is, what is that about? And what happened to her, you know? I mean, after that? That's the big question that was always in my mind when I was, at least between 6 and 16, that was my big thing. Okay, what happened to her?

- [Anne] Were you raised religious? Did you have that story?

- [Marcelo] So my family is Jewish, but they weren't very reli- They weren't Orthodox Jews, and more reformed. So traditions, yes, but not so much the belief in all the details of the Old Testaments and stuff like that. But in all the monotheistic, big monotheistic religions, there is an element of the supernatural that is very present. And I tried to connect with that. So I was obsessed by supernatural stories and supernatural beings and vampires in particular were fascinating to me because they were not, they were both living and non-living.

- [Anne] Yeah.

- [Marcelo] So they had a foot in the world of the dead and a foot in the world of the living. So I said, Hey, maybe if I became a vampire, I could go and connect with my mom.

- [Anne] Hmm. Well, and you were growing up in Rio, right?

- [Marcelo] Yes.

- [Anne] In Brazil, which must be filled with stories of the supernatural.

- [Marcelo] Oh, big time. Because of all the African tradition.

- [Anne] Yeah.

- [Marcelo] There were spirits everywhere, according to my nannies and stuff like that. And my father was a very superstitious guy too. Every Monday is souls day. So people go to crossroads and they light up candles and-

- [Anne] Every Monday?

- [Marcelo] Every Monday, yeah. And the crossroads are essential because that's where the spirits congregate. And then you would see right down your apartment on the corner, you'd see like this little altar with candles, a bottle of cachaça, which is kind of like this sugar cane-distilled thing, like rum, some cigars, and sometimes even a black chicken, dead. Which is an offering for the spirits. So yeah, you can't avoid the other dimension.

- [Anne] Did you ever feel like you were able to be in touch with your mother?

- [Marcelo] Yes, actually, many times. And in fact, if you had asked me, I would have sweared to you when I was nine, that I could see her sometimes hovering on the big long corridor of my house, you know? So I was desperate for that connection, you know? And then what happened is that I started to transition from that to nature, into the need of solitude and being in the natural world by myself. And that's when I started to fish. I was 12, and I would go all by myself to the beach, Copacabana Beach, and just spend hours alone fishing. I mean, what kid does that? And I was surrounded by all these other guys that were just like retired man, and they were always like, what is this kid doing here? And I was just there hanging out, looking at the horizon, for two, three hours, three, four times a week. For years, I did that. And it was really trying to connect with, I dunno, with the vagueness of the horizon in front of you, because it is a weird place, the horizon, when you start to think about that. It is really where the earth and the heavens join. It's the line of connection between one world, our world, and another world, which is not our world, which is up there.

- [Anne] Oh, wow.

- [Marcelo] So...

- [Anne] I can see you feeling drawn to that as though you yourself were hovering there, stuck on the horizon.

- [Marcelo] Yeah.

- [Anne] In a way. Because your mother's death propelled you into this in-between place.

- [Marcelo] Exactly. And then I discovered Einstein in those years, and that kind of changed everything. I realized that some of these questions about space, about time, about duration, about the origins of everything were actually also scientific questions. He has a very wonderful, and I would say mystical way of relating to this kind of hidden intelligence in the depths of nature that we can never quite understand. But it's there. And that the role of the science is to try to, at least once in a while, kind of shed a little bit of light into that mystery. He has this famous, famous quote that I love, which is like, "The most profound emotion you can feel is the mysterious."

- [Anne] Oh, I love that.

- [Marcelo] I mean, who would write that? Krishna Murti would write that.

- [Anne] Yes.

- [Marcelo] I mean, right?

- [Anne] Yeah.

- [Marcelo] That was Einstein. And then I transitioned from this more mystic approach to things to a more rational, let's see what science has to say about all of this. So I think I found a way to be what you could possibly call a rational mystic. A little bit of deep-time history here. We carry the whole history of the universe in ourselves. When we talk about the atoms in our bodies, the iron in your blood, or the calcium in your bones, all those atoms came from stars that exploded 5 billion years ago. So you may say, oh, I'm 20, or I'm 40, or I'm 60. Yeah, but this is just this little arrangement of stuff that is you right now. But this stuff that is making you, you, is billions of years old. And it comes from stars, you know, it comes from out there in space. It traveled gazillions of light years to fall four and a half billion years ago into this nebula that was collapsing to become the sun and the planets. And then in one of these planets, which happens to have water and carbon and magnesium and phosphorus, molecules organized themselves and became alive. And then evolved three and a half billion years ago into a species that is telling a story that is this story. I mean, that is not something that is gonna be happening all over the universe. And that is magical, is beautiful. It's mysterious and is essential because it becomes a part of who we are.

- [Anne] We are talking with Marcelo Gleiser, theoretical physicist and winner of the 2019 Templeton Prize and author of many books. The most recent is "The Dawn of a Mindful Universe." I'm Anne Strainchamps, and we'll be back right after this, onto The Best Of Our Knowledge, from Wisconsin Public Radio and PRX. This is episode three of Deep Time, a new series from To The Best Of Our Knowledge, produced in partnership with our friends from the Center for Humans and Nature. We are tackling a huge question this hour. What actually is time? Earlier, you heard Marcelo Gleiser say he and his theoretical physicist and cosmologist friends don't know what time is, but you can't tell the story of the universe without it.

- [Marcelo] Cosmology is the mother of time. What is cosmology? Well, cosmology is a story that starts with what we call the Big Bang. Well, we don't know what the Big Bang was, but what we do know is that that is when time as we know it started to pass.

- [Anne] And so was there time before?

- [Marcelo] We don't know. We can't know. It's an unknowable. There are theories, models which are incredibly abstract, but we have no clue if they're right or wrong. But we do know something happened in the universe about 14 billion years ago, where what we now call time begun. And the beautiful thing about that is that because the universe is expanding, points in space are stretching away from one another, that change, that transformation, defines the passage of time. So there is something called the cosmological arrow of time, which is saying that the universe had a beginning, and time is changing, it's moving forward. Things are happening in this universe because of this change of time. So there is the overarching, the mother time, is the time, the clock, the universe has itself.

- [Anne] So when you said, "We don't know what the Big Bang was," but essentially it's when time began.

- [Marcelo] Yeah.

- [Anne] How close can we get to that start?

- [Marcelo] Okay, that's, that's a good question. So we can tell the story with confidence from a second on. 'Cause that's when the first atomic nuclei were made. One second after the Big Bang. And you can push that further back to about 100,000th of a second, which is when protons and neutrons, and you know, and you can ask some of my friends, they say, you can go even further back because we can do experiments in Switzerland at CERN, where we can simulate what the universe was like at about 1 Trillonth-

- [Anne] A trillionth!

- [Marcelo] Of a second. And you say, wow, that is so close to zero.

- [Anne] Yeah.

- [Marcelo] Yeah, from our human perspective it is. But for a particle, it's an eternity because a photon, a particle of light in a trillionth of a second can go across a proton distance. The distance of the size of a proton, a trillion trillion times. So you try growing a trillion times around the earth, for example. So those times that for us look ridiculous, are huge for those particles, which is what existed then. Then the effort, of course, is to always push this boundary as further back as we can.

- [Anne] Could we ever know what was before?

- [Marcelo] I don't think so, but that's a debatable answer on my part. The concept of before and after comes if you believe in the flow of time. And as Stephen Hawking very wisely said once, he said, "Asking what happened before the Big Bang is asking what is north of the North Pole?" That's where language fails reality.

- [Anne] Can you imagine in your head any feeling, any sense, of before the Big Bang?

- [Marcelo] No.

- [Anne] Really? Not even...

- [Marcelo] I mean I've-

- [Anne] Not even blankness?

- [Marcelo] I've worked in models, mathematical models where instead of having a big bang, you have an infinite sequence of big bangs. So the universe expands and then collapses and expands and collapses. The universe is like a beating heart.

- [Anne] Wow.

- [Marcelo] And right now we are in one cycle, which is the cycle of expansion that eventually is gonna end and it's gonna go back. And every time this happens, the laws of nature may change. But this is all very speculative. It's awesome to do those models, but we don't know, unfortunately, despite 50 years of very hard work by very smart people, we have beautiful theories like string theory and a bunch of others, but we don't really have an understanding. So we don't know what the big bang is. And in my opinion, it's an unknowable. It's not a question science can answer.

- [Anne] I keep thinking about a thing you said earlier that you're a trail runner and an ultra marathoner, right? So wait, how long is an ultra marathon?

- [Marcelo] It depends. Depends on the race, on the terrain. I've done a 100k races.

- [Anne] Oh God!

- [Marcelo] So about 62 miles, that took me 20 hours to finish.

- [Anne] You just run for 20 hours?

- [Marcelo] Well, you run, you hike, you walk, you sit, you eat, you run, you hike, yeah. But the idea is to cover the distance in the fastest possible way.

- [Anne] So I was thinking you said there's a thing in that community, you're safe to get comfortable with being uncomfortable.

- [Marcelo] Yeah.

- [Anne] Do you feel like doing those extreme marathons is almost like training for thinking in the kind of terms we've been talking about?

- [Marcelo] Yes.

- [Anne] Really?

- [Marcelo] Absolutely. Brilliant.

- [Anne] How so?

- [Marcelo] Well, because just think about it. So research can be very frustrating because you're always pushing the boundaries of your knowledge, right? And you're going into places you don't know and you don't know if you're gonna be successful. In fact, failure is essential in research. And the same happens when you push the boundaries of your body beyond the limits that you think are possible. If you had told me 15 years ago that I was going to go out and run 50 miles or 60, 70 miles in a day, I would say, "There's just no way that can be done." But guess what? It can be done. But it is through tremendous amounts of training and suffering, you have to deal. We call it the pain cave. You know, you have to deal with a lot of physical pain, a lot of physical suffering, because you're hungry. You're severely calorie-deprived. I mean, you're spending 5-6,000 calories or more in a race like this, and you cannot eat that much. So you're weak, you are dehydrated, your muscles hurt like crazy and you still push on as you do these things, you are really stripped of everything that you think you are. Your arrogance, your sense of "I'm the best," or your sense of, "I know this." Or a sense that you are in control. You are not in control anymore. Your body is falling apart. And yet you go with a sense of purpose. Well that's exactly what we do when we are doing research and we try and we fail. And sometimes it's exhausting mentally. And yet you push the boundaries. And there is more. In the ultra running, in the trail running, when you're really tired, that's when the spiritual connection with nature really is magnified, because you're stripped of yourself. You know, it's deep moving meditation and you fall into some sort of transcendent state of the self that is very profound. Sometimes you cry, sometimes you have these incredible highs of joy and sometimes you have some very deep lows of pain and suffering, but you are completely stripped to the absolute essence of who you are. And you get to know yourself so much better for that.

- [Anne] Well, in my head, I have the image so strongly of you as that 12 year old boy standing on the shore just looking for hours at the horizon. The place where the two worlds of sky and ocean meet. And it just seems to me that something in you propels you toward that horizon all the time. Is everybody in your family as driven to breach that boundary?

- [Marcelo] I don't think so.

- [Anne] Why do you think you are?

- [Marcelo] Why do I? I think that my mother's death turned me into a guy obsessed with life. And I think that if anything, you know, my biggest drive is that I love being alive and every day should be a celebration of that.

- [Anne] Thank you. It was wonderful talking with you, thank you.

- [Marcelo] Yay! Very emotional.

- [Anne] That's good.

- [Marcelo] Yeah. These are big conversations.

- [Anne] That's Marcelo Gleiser. He's a theoretical physicist, essayist and endurance trail runner. He's written seven books about science and philosophy. It's most recent is "The Dawn of a Mindful Universe." This is episode three of Deep Time, a series about reclaiming a different kind of time, less clock-driven, more earth-based. So what changes? If we think about time on the scale of the universe, on the scale of a subatomic particle or a neutron star, a black hole, or a thousand galaxies, for writer Marjolijn van Heemstra, it was kind of transformative.

- [Marjolijn] When I was writing the book, it was end of 2018, beginning of 2019, and at least here in Europe for a lot of people, it was really a time when we really woke up to the idea of climate change. And it was also the time that people started to feel this sort of panic and not being able to breathe because what is coming at us. From this place of worry, also with two very small children at the time, I started to look for something that would give me, like, literally perspective. Because when you have the feeling that future is no longer something to look forward to, it can make time seem very suffocating and life seem a bit suffocating. And then I remembered this photo.

- [Anne] It's a photo of the Hubble Ultra-deep field.

- [Marjolijn] When I first saw it, it looked like a lot of fractures as if something has broken into millions of pieces. What you actually see is 3000 galaxies, photographs in a timeframe of three months. And it's so, so huge. I mean, we cannot even imagine how big it is. And it's only a fraction of everything there is. This photo moved me very much because from one side it makes you very small. You can be annihilated in comparison to that. On the other hand, yourself in relation to something so big.

- [Anne] Writer Marjolijn van Heemstra, the title of her new book says it all; "In Light Years, There's No Hurry." We'll be back with more cosmic perspectives after this. I'm Anne Strainchamps, and this is To The Best Of Our Knowledge from Wisconsin Public Radio and PRX. We're talking about time, osmology and the universe, this hour. Unfathomably large concepts, but that's kind of the point. We are living in tense times. Somewhere it always feels like a clock is ticking. So when you're trying to cope with rising urgency and anxiety, it helps to go bigger. Marjolijn van Heemstra is the poet laureate of Amsterdam, had also a space reporter. And a few years ago she read about something called The Overview Effect, a mental shift. Many astronauts have reported. Steve Paulson, who is always up for a cosmic perspective, called Marjolijn in Amsterdam to ask what it is.

- [Marjolijn] Yeah, the overview effect is this sort of overwhelming experience. Also a sort of change of mentality that astronauts can experience when they look at earth from space. And many of them have reported on this, when they came back. I must say not all of them, some of them sort of seemed very immune to the experience, but a lot of the astronauts come back a little changed. Having seen how earth is actually, is not a collection of all different places, it's a unity. It's like one animal. It really changes your life. I even read that the people coming back from the Apollo program, they weren't allowed to join the Army anymore because they were afraid that they would be so soft after this trip, that it's ridiculous to fight people because borders are just manmade. So it's absurd. I know that one of them said something like, "Look at that you son of a , how can we ever fight against something like that?"

- [Steve] So you developed a project where you wanted to see if you could find some equivalent on Earth. Not blasting off into space, but just through our lives here. How did you go about searching for this?

- [Marjolijn] Well, I decided to make a space trip on Earth. So for about a year, I visited a lot of people and projects that were all dealing with the space travel or cosmology. So poets, but also theologians, people in labs that were preparing for Mars missions. That was my sort of being an urban astronaut. And also I realized that if I wanted to have an experience in which I could sort of see unity, I should also do that in my own neighborhood, for example, where gentrification was a huge problem, still is, and I was sort of the face of this gentrification. So I decided, okay, I will focus both on the stars and on the little garden I share with my neighbors to really zoom out and really zoom in at the same time.

- [Steve] I get looking out, but looking into your neighborhood, how does the overview effect play into that?

- [Marjolijn] Well, I decided that besides writing about space and using all those insights in my own life, I should bridge the gap between me and my neighbor Bo, who lives under me. And Bo is really the face of like the old neighborhood, the people who suffer from the gentrification, the people who feel a big distance between them and people like me coming in and you know, sort of setting up the neighborhood to what we want and what we need. You don't go to space alone, right? You have someone with you. So I thought I should take Bo as my fellow astronaut on earth.

- [Steve] Tell me more about that. How did you connect in this larger project of sort of experiencing space?

- [Marjolijn] Well, it was really quite easy, actually. I asked him about his experience and you know, he remembered the first moon landing, for example. And I asked him when he felt this overview effect. And he told me about walking his dogs and looking at the sunset and having this idea of freedom and connection with everything. Looking at his fishes. His fishes were very important to him. He ended up giving me the fishes, which I felt a little bit bad about that, but it was his own choice. Only some of them died because I didn't take care of them well enough. But anyway, also we ended up doing a theater show together through the country with this story. And we became very close. We still are.

- [Steve] You also mentioned that you have two young kids. It's not as if you're just going off having these experiences of awe. I mean, you're dealing with a messiness of daily life. Reading, you know, about all the troubles in the world, the wars and poverty and authoritarianism and all of that. While you are seeking these transcendent experiences. And I'm wondering sort of how do you make sense of the overview effect? How do you put that in context, in the midst of, of all this stuff that happens in our lives?

- [Marjolijn] Well, the thing is, what I think that they see, these people from space, is that everything happens all at once, in the same time, in the same place. 'Cause you see this organism in space and you know, ha, there's a war, there is love, there is peace, there is, it's all there. And it's all carried by this little, well, it's not that little, but from space it is, it is by this little planet. But also if you zoom into your own life, you realize always how everything is existing next to each other, right? So somehow for me, the essence, maybe, of the overview effect was the coexistence of everything. Also, Covid happened when I was writing this book, which was interesting because then we had all these interviews with astronauts because they were the experts on living in an enclosed environment. So yeah, that made me feel like an astronaut as well.

- [Steve] Now I know one thing you did was you, you started going out at night, you wanted to see the night sky, you wanted to be in darkness. Which is probably a little hard to do being in Amsterdam in the middle of a very lit-up city. How did you try to embrace darkness?

- [Marjolijn] Oh, well that, I think in that way, writing this book has really changed my life because I've become a darkness activist almost full-time now. We are one of the most light-polluted cities in the world, so it's really bad. So I started this project called The Night Watch, this September we organized our first Amsterdam dark festival and we had 2000 people going into the night.

- [Steve] Why are you so interested in being in darkness? Why do you think that matters to us?

- [Marjolijn] Well first, of course, I came into the darkness because I wanted to see the stars. But then of course living in Amsterdam was so hard to find. And I started to dig more into the light pollution and what it actually does to animals, to people, how it makes us more depressed, more obese, how many insects it kills. And what I also noticed is when you're in darkness, you experience your surroundings so differently. Not being able to really see your own boundaries, you feel in a way maybe what the overview effect can also give you. You feel like you transcend yourself a little bit.

- [Steve] You talked with one astronomer who said that "If you really wanna get the effect, it just bowls you over." You have to be able to see at least 450 stars.

- [Marjolijn] Yes. Yeah, like 400. And okay, there is a sort of a boundary for how many stars you need. Yeah, so 450 stars, well we don't have that in Amsterdam,

- [Steve] But I mean, it's one thing to look up at the night sky and see the Big Dipper and a few stars and a couple of planets and the moon. It's something else to see literally hundreds of stars. It's an entirely different experience.

- [Marjolijn] Yeah, and the Milky Way as well, I think. That really adds to the experience. Yeah, totally.

- [Steve] Why, what changes, do you think?

- [Marjolijn] It's a sense of something uncontrollable. I think this whole feeling of awe is about not having control. If I look up here in Amsterdam, I see maybe 70 stars and some satellites. So it still feels like a human-made world. And I think if you have this sense of so many stars and seeing the Milky Way, it's like literally uncountable. And that's where the dizziness comes in. And that's where you get lost, a little bit. And I think you need this sense of being a bit lost to be overwhelmed because, well, yeah, you have to let go of this feeling of control. And that's why I like walking in the dark so much because you have to go really slow because you can fall and you never know what's gonna happen and you lose the way. Even if you know a place, you lose the way all the time.

- [Steve] So one final question. I was struck by one of your notes at the end of your book about a piece of music that you listen to a lot. It's Max Richter's "On the Nature of Daylight," which was part of the score for the film "Arrival," which of course was all about first contact with an alien intelligence. Why that piece of music? What does that do for you?

- [Marjolijn] Well, I think it has to do with deep time and how our ideas of time can maybe change by looking at space a bit more. And that film, I've watched it a few times, but it just moved me so much about how we are stuck in this chronological time. And for me, it was a very, maybe it's a big word, but in a way healing to realize more and more how many years things have existed before we came. That even looking at the moon is like 4.2 billion years since it was formed. And all these layers of earth that are sort of the memory of our planet. So if you look at time, like human time at this moment, it's frightening, because we don't know where it's going. We don't know how long we have until it gets really uncomfortable. And for many people it already is. So it's a frightening time, in a way. But then it's a little bit, I don't know if I can find the right word, because I don't wanna say like, ah, you know, it's nothing. The planet will restore itself. But it is a little bit comforting that the planet has been there for so long without us. And I'm not saying that we shouldn't fight for it and we shouldn't do everything we have in our power to stop what's happening now. But, you know, earth will continue and many of these time layers will continue and new time layers will come and we will be part of a new layer and we might be part of the oil that another civilization will use for their transport, whatever. And that somehow is a comforting idea.

- [Anne] Marjolijn van Heemstra talking with Steve Paulson. She's the poet laureate of Amsterdam, a space reporter and author of "In Light Years, There's No Hurry." One of the best antidotes I've found to feeling stuck in chronological time is cosmology. I can't tell you how many people have recommended Carlo Rovelli's book "The Order of Time" to me. It'll make you question everything you thought you knew about reality. Rovelli's an Italian physicist trying to bridge the gap between Einstein's theory of general relativity and quantum physics. He writes about time and black holes and now white holes. And when the stars aligned recently, we both wound up in Santa Fe on the same day and arranged an interview. He had a cold, I was running late, but somehow I did finally make it to his door bearing orange juice and cough drops and microphones. I was feeling tense about whether this was gonna happen, whether we'd managed to do the interview, and then I sat down at breakfast. I told you I took "The Order of Time," was kind of rereading some of it and there were passages that just jumped out at me. Especially, we think the world is things, it's events. And just for a second I thought, well if I just think of all of this, it's just events. I'm just in a sea of events, it's okay.

- [Carlo] Yeah.

- [Anne] Does this make sense to you at all?

- [Carlo] A lot because it has happened the same to me.

- [Anne] Has it really?

- [Carlo] Yeah, absolutely.

- [Anne] So how does that play out?

- [Carlo] Well, I get stressed like everybody else. I panic about time like everybody else. I have too many things to do which I cannot do. And like everybody else, of course, but actually I don't know if it's just my physics or just simply the fact I'm growing older.

- [Anne] So you've been working on "White Holes," your new book.

- [Carlo] Yes.

- [Anne] And that's a whole new picture of what time can do. Time can reverse.

- [Carlo] Yes.

- [Anne] Time can go backwards.

- [Carlo] Yes. Perhaps the biggest surprise in the last decades it says is that the universe is full of black holes.

- [Anne] Which 20 years ago, black holes were contentious. Some people didn't, some scientists didn't think black holes did exist. Now there's photographs of them.

- [Carlo] Very clear evidence. We have photographs, we have the gravitational wave produced by black holes. So now we are all convinced that there are black holes out there. Not only there are black holes out there, but there are many, many black holes out there.

- [Anne] What was it like for you to see that first photograph of the black hole? Do you remember?

- [Carlo] Yes. It was an incredible emotion. It's like, you know, we have been studying an animal, mysterious all your life, and then you see it. Wow, it exists, it's real.

- [Anne] Did people, I don't know, jump up and down?

- [Carlo] Actually the best experience has not been the picture of the black hole, which is a few years ago. But a little bit before that, there was the doubts of the detection of the gravitational waves that was produced by black hole. Since there are so many black holes in the sky, they can meet and fall into one another. They fall into one another. They start orbiting, turning around, then orbiting faster and faster and getting closer and closer. Faster, faster, faster, faster, faster. Closer, closer, closer, and then boom, they just eat each other, so to say. And if they do so, they produce this enormously strong oscillation of space, which is what was detected. The announcement of that was given publicly and the press conference was during a class I was giving to my students in Lycée on general activity. So I told the students, look, there is this press conference. They say they're radiational waves, they're not sure what they've got, what they've seen. They say they've seen. And I turned the computer on in front of the class. But before I gave them the theory, I explained them that the black hole emerge and they produce this wave and oscillations, which first is slow and weak and then become faster and higher. So if it was a sound, it would be something like... It's a chirp, the chirp of the black hole. And I drew the shape of this wave on the blackboard. Then we turn the computer on to the press conference,

- [Radio Announcer 1] The black holes are getting closer and closer to one another.

- [Carlo] There's great emotion.

- [Radio Announcer 1] They're going to merge. Boom. The first time that this has ever been seen.

- [Carlo] As something said,

- [Radio Announcer 2] We can hear gravitational waves, we can hear the universe.

- [Carlo] And this is a signal that we have measured.

- [Radio Announcer 2] There's a rumbling noise and then there's a chirp.

- [Carlo] The shape of the wave appears. It is exactly equal to the shape of drawn of the black hole.

- [Radio Announcer 2] That's the chirp we've been looking for.

- [Carlo] The students, it was a class of 20, 30 students all together "wow!" That's like science at it best when you really, when you really, science is shining.

- [Radio Announcer 1] Gravitational waves. We did it.

- [Anne] So I'm thinking that people listening might think, I thought you were talking about time. Why are you talking about black holes?

- [Carlo] Oh, because black holes-

- [Anne] I think black holes have a lot to do with-

- [Carlo] Because black holes is all about time.

- [Anne] How so?

- [Carlo] A black hole is a defamation of space and a defamation of time. So if you go near a black hole, if you look backward, you see the rest of universe going faster and faster and faster. So time goes a different speed. And if you fall into the black hole, what I think is gonna happen, this is a white hole, and you find yourself billions and billions of billions in the future.

- [Anne] Wow. So what is a white hole?

- [Carlo] So by the white holes, this is where quantum gravity come in. So this is where isotheory is not good anymore and quantum gravity is needed. And what quantum gravity says, evolution in which the black hole becomes longer and narrower stops and bounces back, comes back. There's a bounce. And everything that was falling in now is jumping up. It's bouncing back. And that's a white hole.

- [Anne] So in some ways it's the same as the black hole, it's just in reverse.

- [Carlo] Exactly. It's the same process as a black hole, but in reverse.

- [Anne] I'm imagining putting my hand inside a glove and then pulling my hand.

- [Carlo] Oh, very good. Exactly. But the white holes are also prediction of isoequations and like black hole in the past you can find in books, oh yeah, but these are not real things, just predictions that don't exist in the real universe. But I believe that they may well.

- [Anne] Just wait.

- [Carlo] Just wait, yeah, exactly.

- [Anne] Our senses tell us that the world is made of things.

- [Carlo] Yeah.

- [Anne] But science and especially quantum physics tells us no, the world is made of happenings.

- [Carlo] Yes. The world is not made of things. Once we study things, objects, we realize that they're actually processes. Why? Because a glass, for instance, is really many dancing electrons and protons once around the other who just in the dance, keep a sort of shape for a while, but it's for a while.

- [Anne] Why do I find this so comforting?

- [Carlo] It is, because it brings a levity, likeness to the world. One reason for which I find this emotionally meaningful is because of course we ourself are processes and not things.

- [Anne] Yeah, it's a remark you make near the end of White Holes that we keep making the mistake of thinking that we are studying something that's out there. Whereas in fact we're always studying it from inside. Time, you can't really study time from the outside.

- [Carlo] Yes. Whatever we are studying, we're studying ourself at the end of the day, and we recognize the things of nature as brothers and sisters of us. We have learned with Darwin, absolutely literally that we're brothers and sisters of all the rest of the living beings on earth because we have common ancestors. You and I, your mother, mother, mother, my father, father, father, were making love together years ago. And the same is true with plants and with birds. So we are just part of what we are. We see around us and we want to relate to things. Not like me and that, We want to relate to things like me and you.

- [Anne] Me and you.

- [Carlo] And that's what pull us toward things. That's why we study black holes, I think, and study white holes because they're our brothers and we exist by getting a relation to them.

- [Anne] Yeah, yeah. You talk so beautifully about saying that we should really not talk about the universe as it, we should address the universe as you.

- [Carlo] You.

- [Anne] I guess what I keep being curious about is having thought about time for so long and discovered things about time. Do you now, in ordinary life, notice things about time that other people don't that I might not?

- [Carlo] Maybe all this has given me and coming back to your first question, more serenity.

- [Anne] Yeah?

- [Carlo] I view myself as a little wave in the happening of things. That helps me to accept my responsibility, but also my lack of importance. The fact that my life is finite, I'm gonna die. And that's not too bad. I view reality in this fluid, and I would say unstable, constantly unstable way, it helps accepting everything.

- [Anne] Yeah. That's Carlo Rovelli. He's an Italian theoretical physicist, author of "The Order of Time," which was an international bestseller, and he's got a new book out called "White Holes." A big thank you to the people at the Santa Fe Institute for helping us meet in person. And more thanks to go around. Deep Time is a special series produced with help from our friends at the Center for Humans and Nature, and with generous support from the Kalliopeia Foundation. You'll find more information and more deep time episodes on our website at To The Best Of Our Knowledge is produced at Wisconsin Public Radio by Charles Monroe Cain, Shannon Henry Kleiber, Mark Rickers, and Angela Bautista. Our technical director and sound designer is Joe Hartke with help from Sarah Hopeful. Additional music this week from Kai Engel, Sergei Charimisonov and Ketza. The executive producer of To The Best Of Our Knowledge is Steve Paulson and I'm Anne Strainchamps. From all of us, happy night walking, and stargazing. Somewhere in the dark, we're out there right along with you. PRX.

Last modified: 
November 20, 2023