Science Friday - Neutrinos, Book Club, Air Conditioning. July 13, 2018, Part 1

Episode Date: July 13, 2018

In 1988, physicist Stephen Hawking’s wildly popular A Brief History of Time introduced general audiences around the world to scientists’ questions about the Big Bang, black holes, and relativity. Many of those questions remain unanswered, though the science has advanced in the 30 years since the book was first published. Hawking, who passed away this spring, was known not just for this book, but for his enthusiastic and persistent communication with the public about science. And this summer, the Science Friday Book Club celebrates his legacy on the page, and off. Join Ira and the team at Science Friday as we read A Brief History of Time and ponder the deep questions about matter, space, and time. We’ll read the book and discuss until late August. And we want to hear from you!  Neutrinos are particles that are constantly raining down in the universe. They are created from nuclear reactions in places like our sun, distant stars, and even on Earth. But the source of higher-energy cosmic neutrinos formed deeper in the universe is still a mystery. Researchers have built telescopes to detect these low and high energy neutrinos as they pass through the Earth. One of these telescopes is IceCube, which is buried deep beneath the ice in the Antarctic. In September, IceCube detected one of these cosmic neutrinos and alerted the Fermi Gamma-Ray Space Telescope and other observatories. These telescopes were able to trace the source of the neutrino to a flare up in a blazar—a black hole at the center of a galaxy—4 billion light-years away. When the mercury soars dangerously high, air conditioning can help save lives that might otherwise be lost to heat exhaustion, heat stroke, and other stresses brought about by heat waves. But there’s a downside: it can take a lot of electricity to keep you cool. New research published in PLOS Medicine earlier this month assesses what happens when the demand for air conditioning rises with the temperature, and why saving those lives might also cost lives. Senior author Tracey Holloway, a professor of atmospheric and oceanic science at the University of Wisconsin-Madison, explains. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato. A little bit later, we'll be having our book club where we'll be talking about Stephen Hawking's a brief history of time. But first, people like to say that our brain is like a computer, right? It's a usual metaphor. But in reality, no computer comes close to matching the power and complexity of the human brain. But that hasn't stopped technologists from trying to build an even better computer that acts even closer to the human brain. and one company is closer now to that goal. Here to tell us more about this milestone in brain-inspired computing is Amy Nordrum, news editor at I-Triple-E Spectrum. Well, there's all other selected short subject in the size.

Hi, Amy. Hi, Ira. So what's the breakthrough reach this week? Yeah, well, this field of neuromorphic computing, as it's called, has a bunch of big research projects going on right now, and one of the biggest is called Spinnaker out of Europe. And this week, a group related to that project announced that they had done the largest simulation,

on their computer to date. So they did a simulation of a neural circuit that contained 80,000 neurons and 300 million synapses. So they were able to run this simulation and then compare it to traditional software running on supercomputers today that's typically used to do

these kinds of neural simulations. And they found that the results of their new hardware, their new system, were as accurate as this top-of-the-line, state-of-the-art neural simulation software that most scientists are using on supercomputers today. So this is a good step for the process.

It means that they're on the right track. And then as they continue to scale up their neuromorphic computer called Spinnaker, the project will hopefully be able to produce results that are even more accurate and do it with less power and faster than the supercomputers that are used today for these kinds of things. And why do they think they need to create such a computer like this? They just wanted to get, to recreate the human brain? Is that the idea? Yeah, the thinking is that since our traditional computers really aren't designed, similar to the brain,

If you really want to study the brain in depth, if you want to run a lot of simulations on it, learn more about how the brain learns and adapts and the plasticity elements of it, you really should design a computer that works a lot like the brain. And so in theory, if they continue to scale this project up, they'd be able to do a lot more accurate simulations of our own brains. What if you could get close to that? Think of the ethics considerations here? Absolutely.

I talked with the researcher involved with this project. Last night, Sasha von Albaata, and was asking her about this possibility. and one of the applications that they hope to build to use it for some day is to create a kind of artificial intelligence that's very similar to our own or can provide robots with more better abilities to sense and respond to the world around them. But she also made a good point about how this kind of intelligence could also help you do experiments in ways that could be perceived as more ethical. So right now we're using a lot of animal experiments

and animals to do these kinds of experiments about different neuroscience topics. And this could provide a way to do simulations that would, could possibly eliminate the need for that, which would be a good thing. Let's move on to the next topic. A new study out this week that shows how fish can ignore self-generated sounds to focus on other things in their environment, just like people do, right? We tune out stuff. Yes, and thank goodness we do.

This study has to do with the concept of what's called the negative image. So that is a way that your brain learns to filter out the sounds and movement that your own body produces so that it can pay attention to whatever else is going on in the world. And researchers at the Zuckerman Institute at Columbia University were interested in how this negative images produced within the brain. And to try to figure that out, they looked at a much simpler organism. So they looked at the elephant-nosed fish, which is found in Africa, and does have like a weird snout that looks a lot like a trunk. And this is a fish that produces electrical pulses and very consistently. And then it also senses electrical fields from other fish and organisms in the water.

So it has this issue where, you know, it's producing electricity, but also trying to sense it. it at the same time. And they were able through a series of experiments to figure out how the fish does that. And basically in the fish's brain, as it's sending out motor neurons to produce that electrical pulse, it's also kind of making a local copy of those motor neurons that it sent out, and then using that to filter out and calibrate its response to the world around it, which is a really clever mechanism. Yeah, it sounds very electronic, you know, like we do in filter circuits. Yeah, absolutely. And it's very useful for them. And, you know, a similar thing needs to happen for us to be able to process and respond to the environment around us and the way that we do.

So we might learn something from these fish. Absolutely. The hope is that. There's a lot of study into this. We haven't been able to exactly figure out how it works in humans quite yet, but the mechanisms and the structures and the fish brain can be thought of as a model or similar to the human cerebellum, which is thought to be involved with this process in us. Let's move on from fish to mice because there's a study showing out. that possibly living in a cold climate could lower your chance of being overweight if you're a mouse at least? Well, this is an interesting study actually about the relationship between, so male mice and then their offspring,

and it has to do with brown fat. So brown fat is the tissue that burns energy to produce heat in the body, and it's a good thing to have more of it. And it's associated, having more of it is associated with a lower risk of obesity and being overweight in humans. So researchers at ETH Zurich in Switzerland were looking at what, leads to the presence of brown fat, they decided to study this presence in mice. And they found that male mice that were exposed to cold temperatures before they reproduced tended to have offspring with more brown fat than male mice that were not exposed to cold temperatures before

they reproduced. And this experiment has results that are also reflected in humans. So other studies have pointed to findings that show humans who live in northern climates tend to have more brown fat and also humans that were conceived in the colder habits. half of the year tend to have more brown fat. And so this is an interesting relationship of, you know, environmental factor, the temperature of the father actually being translated into a change in their offspring. That would be something like what we call epigenetic. It's changing the genes somehow.

Exactly. This is not a genetic change, but it is an epigenetic one. So it's changing the way that the genes. Yeah, exactly. It's changing the way that the genes are expressed. In this case, they say it has to do with the cluster of genes and two particular pathways in the mice. So it's a pretty interesting observation on their part.

Wow, yeah. Who knows what else might happen with people? And then lastly, a new study suggests that doctors working in smaller practices experience less burnout. Sounds logical to me. It's actually the, you could kind of see it either way because the researchers were expecting the opposite. Is that right? Yeah, they were surprised by these results. They were expecting, you know, larger practices. You've got more people to, you know, handle different tasks. You can focus on what, you know, what you're good at. And maybe you've got more support in different ways. But they found that physicians, at smaller practices with five or fewer physicians actually were less likely to report burnout. So nationwide, the burnout average for physicians is about 50%, which is a concern

because none of us want to be treated by a physician that's bored at their job or tired of it. But these small practices, it was only 13%. That is a real difference, isn't it? 5013. Yes, absolutely. It's very meaningful. And this is actually good news

because most practices in the U.S. are small practices. I was asking about why this might be the case, and they were saying, you know, small practices deal with things like billing that are stressful, and they have to handle more of those kinds of tasks like electronic health records and managing all of that. But they also tend to have more autonomy. They have more control over their schedule. And they seem to have more of a sense of community among the physicians in the practice itself. And those things seem to outweigh the extra stress that these small practices have to deal with.

Yeah, someone who has been to a small practice and a large practice, well, go to the smaller one. All right. That's a good idea. That's what it says there. Amy Nordrim, news editor at the I, AAA Specter. Thank you very much for being with us today. Now, it's time to play. Good thing, bad thing. Because every story has a flip side.

You know, we're halfway through 2018 and already breaking record temperatures for the lower 48 states this May. This May was the warmest May on record, and this June was the third warmest the U.S. has experienced. So in response, of course, we turn up the air conditioning to stay alive for a lot of people. When mercury soars at dangerous heights, that's what they need to do. But at what cost, new research published in Laplace Medicine earlier this month weighs the downside of cranking up the AC as the climate warns. Tracy Holloway, a professor of environmental studies and atmospheric and ocean studies, Ocean Sciences University of Wisconsin. And Madison is here to explain. Welcome to Science Friday. Thanks, Ira. It's a pleasure to be here.

It's nice to have you. You know, I have been really grateful for my own air conditioning this summer. I mean, it has been so hot. But to what degree is air conditioning actually vital for people's health? Well, the good news is that air conditioning is a really effective way of saving lives on hot summer days. Many studies have shown that having air conditioning at your home or going to cooling centers where people can get access to air conditioning really is an effective intervention in protecting health on hot days. Now, what's the bad news about this? Well, the bad news is that when all of these air conditioners are running, so are power plants around the United States. And most of our electricity comes from fossil fuels.

So when we're burning all of this electricity, we're emitting a lot of chemicals into the air. And on the hot summer days, this is when the chemical reactions in the air are going fastest, and there's a lot of air pollution being formed. So it's the worst time to be emitting this extra air pollution from a health perspective. Yeah, we always hear stories about it's actually the pollution is cooking in the sunlight and the heat. What's it making in that brew? The two main things are ground-level ozone, often referred to as smog. And this is a gas that has a lot of adverse impacts on human health and on agriculture,

from making our eyes itchy to actually leading to premature death. The other pollution, the pollutant that's cooking up is called particulate matter. And this can be either liquids or solids that are sometimes directly emitted, like smoke from a barbecue. But what we're talking about here are ones that form in the atmosphere through chemical reactions. And is there a number for the number of people who die each year from being too hot and being too hot out there? Yeah, about 600 people die each year, according to the CDC from extreme heat. And this is considered an underreported number. So it's probably quite a bit more than 600 a year in the United States.

Closer to 1,000, you think? It's hard to say, but it's considered a conservative estimate. So there is a trade-off here, and it's obviously as the climate changes, is going to get hotter over this century, right? Yeah, yeah, exactly. And so then we're going to be depending more in air conditioning, and the idea is if we're going to be getting more pollution, we have to find some way of cutting back on that pollution.

Right, and the good news is that this is something that's within our control, There are a lot of solutions to be getting the cooling and the air conditioning that we need while having cleaner air. And this can come in the form of moving our electricity system toward less emitting sources, designing buildings that are easier to cool, and having air conditioning units that are more energy efficient. Yeah, okay, so there is some hope for us. Thank you very much, Dr. Holloway. Thank you very much. Tracy Holloway, Professor of Environmental Studies at University of Wisconsin in Madison. And we're going to take a break, and when we come back,

we're going to talk about pinpointing one source of high-energy neutrinos. Scientists have detected a single, this is amazing, a single neutrino from a source, what, 4 billion light years away. That was some feat and involved a lot of ice. You'll get, it's going to be a pun. You'll get it. I'll talk about it later. After the break, stay with us.

This is Science Friday. I'm Ira Flato. I know you've probably heard about neutrinos. talked about them over the years. They have been called the ghost particle created by nuclear reactions in the sun, and they're particles that pass through just about anything without leaving a trace, and because there's so many of them, they're raining down on us all the time. But there are even higher energy neutrinos coming from way out in the universe.

These are even harder to detect. Figuring out where they come from is a bit of a mystery. Well, this week, scientists came a little closer to solving that puzzle, and all it took was a giant collaboration of scientists and a network of telescopes scattered around the world. An observatory called Ice Cube buried a mile deep in the Antarctic ice. All of this to detect one neutrino. One neutrino made all the difference. And so we want to know what made this single neutrino so important. Well, we're going to talk about it.

Scientists were able to follow it back to its source. This is the first time they could take a single neutrino and follow it. Four billion light years it traveled, followed it back to its source. They traced this one way back. You know, what is? And the source was something called a blazar. You know what a quasar is? It's a cousin to a blazar.

How does this all work? What does it mean for the understanding of universe and astronomy? Good question. A massive team of scientists published their results this week in the journal. Science. My next guest is an author on one of these studies, and he's here to answer all those questions. Chad Finley, an associate professor of physics at Stockholm University. He's also the former leader of Ice Cube's point source analysis working group. Welcome to Science Friday. Thank you very much. It's nice to be here. Nice to have you. I'll tell all the listeners,

if they have any questions, they can phone them in at 844-724-825, also SciTalk, and also you can tweet us at SciFri. Ice Cube is a neutrino detector. Give us a number 101 lesson, like a neutrino 101, about why this is so important, what Ice Cube is, how this all work? So, yeah, I mean, the goal of Ice Cube, as this neutrino observatory, is to sort of initiate the field of neutrino astronomy. And the goal of neutrino astronomy is to do astronomy but with something different than light, to do it with these neutrino parts. particles. And it's in the same vein as we're doing now in astronomy with gravitational waves, which I'm sure people have heard about before as well. And I mean, each of these things,

already starting with light, when people started to be able to do astronomy with gamma rays and x-rays and radio waves, each of those opened up new windows, and we learned so much more about the cosmos because we could see things that you couldn't see, you know, with optical light. And the idea with neutrino astronomy is similar, that you can learn things about the universe, you can see things. It's like another diagnostic tool that a doctor might have to look into a patient. You can investigate the universe with this different messenger. But the problem, I mean, what makes it challenging and why we're just starting to see things now is what you said, that the neutrino is this ghost particle that hardly ever interacts at all with ordinary matter.

Most neutrinos will just fly to the earth and they don't leave a trace. So that's the challenge that Ice Cube neutrino Observatory has tried to tackle, finding a way to detect a few of these and be able to trace back where they came from. And so this is the first time you could do that, detect one and trace it way back, and you traced it back to something called the Blazar, 4 billion light years away? Tell us what that is. That's right. So, I mean, what we've seen is an association.

It started with this first neutrino, and that kick things off. And we've been able to see more neutrinos since then, which made us, you know, more convinced that this really seems to be the first neutrino source that we're pinpointing in the sky. Because we have the directions in the neutrinos, but if you look back in the sky, there's out to the edge of the universe, there's actually quite a number of objects that could be in the same field of view as that neutrino. So you need, it takes a lot of work to really make a convincing association between the neutrino and the object. And what happened here was we had started about a year, two years ago, from now, but about a year before this event happened in September of 2017, we had started

an alert program so that when we get this ice cube observatory, our telescope is built into the ice, into the glacier at the South Pole and Antarctica. It's a crazy place to make a telescope, and it's a crazy thing that it actually sits in the ice, about three kilometers deep, and watches for neutrino interactions that can happen in the ice. And when we get a really high energy neutrino, the kind that we might only see two or three times a year, we send out an alert. It's a new system that we had started, and we could send out an alert within about 30 seconds from when that neutrino interacted in the ice. It's a public alert that goes to all observatories. In fact, anyone who wants to track these alerts can receive them and can find them on the web.

And that means that telescopes can then go point and look and see what's happening in that spot in the sky. And when this one went out last September 22nd, the Fermi satellite, gamma-ray satellite, made a connection in the same direction in the sky. They had noticed that there was a blazar that was in a flaring state. It was an enhanced state of gamma-ray emission. And what the blazar is, when we've known about blazars for some time, they're one of the craziest objects in the universe. Every galaxy, we believe, has a massive black hole at its center. has one several million times the mass of the sun, and some galaxies have them that are billion times a mass of the sun. And most of those are relatively quiet. But in some galaxies,

those supermassive black holes are busy eating up gas that's around them. And when they do that, they shoot out these jets of particles, these extreme jets of particles that go out to axis. There's sort of the top and bottom axis of the black hole. Those jets go out of, you know, shoot out of the galaxy. And if one of those galaxies happens to just, be lined up so that that jets pointing at us. So it's sort of like you're looking into the into the beam of a lighthouse. Then we get this intense blast. And so we can see these things out to the, you know, the edges of the universe because they're so bright when we happen to be looking at them. So the blazer is a special case where not only you have a supermassive black

hole that's eating matter and devouring and shooting out these jets, but the jets also pointed right at us. And so this blazer had perked up a few months before and it had been in a much higher state of gamma-ray emission. And so this connection between having such a high-energy neutrino and having it just line up perfectly with this blazar, this started to make a convincing case that there's an association that these blazers can be the source of the high neutrinos

and also the high-energy cosmic rays, which has been a mystery going back to 1912 when cosmic rays were first discovered, where in the universe the high-energy cosmic rays get created. So this is just a quasar that's pointing at us with those beams. That's right. That's right. I mean, if it was pointed somewhere else, it's still possible to see them, but it wouldn't be as bright.

And probably the particles and the neutrinos that would be created, and one of those jets would, you know, point off into some other part of the universe. So how many of these do you need to discover before they become useful for your, what do you call it? It's astronomy? Do we still call it astronomy? astronomy, astrophysics, astroparticle physics, there's a lot of different names that people use it for. So, I mean, what we've seen so far, you know, there's sort of two, where we've just arrived now, this is a milestone for neutrino astronomy to be able to start to pinpoint one source is, you know, we're hopefully closing the door, beginning to close the door on this old question of where nature's, you know, most powerful.

particle accelerators, you know, millions of times more powerful than the large Hadron Collider or the Fermilab accelerator. You know, somewhere in the universe, these particles are being accelerated, the enormous energies. And the neutrinos are tracer of that. If we find the high-energy neutrinos, we can say this is where it's happening. And if we start to say, we start to be able to answer that question, it's Blazars. That's at least one of the sources.

There may be other sources, but at least we start to have one that we can study in detail. But that's the flip side, is that now we want to understand, now it's the diagnostic. Now we can start to, people have been studying blazars with gamma rays, with x-rays, with radio waves, and they're really fascinating objects. They're extremely variable, despite being so massive, these massive black holes, they can sometimes flare up and turn off in a matter of minutes. Sometimes they flare for months. It's unpredictable.

No one really knows when they're going to turn on or off. and so the neutrinos will give us a new window into what's going on. The neutrinos that we see are actually about a thousand times higher in energy than the highest energy gamma rays that people can see from these blazers. So we're looking at a much higher energy, and we're using these particles that are created in different processes. And already we're seeing some strangeness in the fact that we have this one neutrino associated with this flare, but we also look back on our data,

and we saw more neutrinos coming from this source, which were hard to find before because we didn't know how to do the analysis right at this spot. We didn't have a reason to look exactly at this blazer and do this deep analysis. But we see that there was neutrinos that being emitted before in 2014, 2015, over a period of months.

And there's not the same enhancement of gamma reactivity at that time. So maybe there's something different going on in these two periods of time. Maybe sometimes you see an enhancement with gamma reactivity. arrays and sometimes you don't. So we're starting to, we don't know where this is going to take us, but this is a lot of new data. And this starts to become a new window into the, you know, the extreme physics that we can study without leaving our comfortable planet. And, you know, we can't do these kinds of physics experiments on Earth. We wouldn't want a supermassive black hole, you know, in our laboratory. But we can study it where this happens in the universe. And so

it's also a way of, you know, understanding physics, understanding extreme states of matter and energy. Let's go to the phones. Let's go to Los Angeles. Stuart. I welcome Science Friday. Hi, yes. This one might be a little heady, but I'm kind of curious, can you explain the substantive nature of the neutrino, maybe in relation to gamma rays and radio waves and also in relation to, like, quartz or smaller particles of matter? Good question. Yeah, that's, I mean, that's probably the easier way. It's in their fundamental particles. So if you're familiar with quarks that make up protons and neutrons, and then you have also the electrons, the fundamental particle. And so those families of quarks and the electron are the familiar ones. And then the cousin of the electron, I would call it that. It's sort of electron's kin

is the neutrino. So it's also a fundamental particle. But the difference is that it doesn't have any charge. And so it doesn't interact. It doesn't have any of the interactions the other particles that doesn't have the electric interaction. It doesn't have the strong force interaction that holds the quarks together. It only has this thing called the weak force interaction. And as you guess from the name, that means it interacts very weakly. So they most of the time just tend to, they're created and then they just zip off and they don't ever interact again. But they're in that same level of fundamental particle as the quarks and the electrons. and they should be created, and we know they're created in the nuclear fusion processes in the sun.

They're created in nuclear reactors, and they should be created in the high-energy particle collisions where cosmic rays are born. So that's why we can use them to do astronomy, because they're creating other places in space, and we can look and see where they're coming from. Now you say you've already looked into your data and found other instances. Yes, yes. The more you look, the you think the more you'll find. That's, I mean, that's what we're hoping for is that now with this lead, we actually have an immense amount of data, but the troublesome thing is that we have an enormous number of neutrinos.

We actually have close to a million neutrinos recorded, but most of those are background neutrinos. They're created, oddly enough, they're created by cosmic rays hitting our atmosphere. And the cosmic rays hit our atmosphere, they make neutrinos, and we detect those as well. well. So fishing out, you know, the rare neutrinos that are actually from space, from deep space, from billions of light years away, from this background is what's, you know, a very big data analysis challenge. And once you have a lead, and that started with that first neutrina that we sent the alert now from, once you have a lead, then you have an idea how to sharpen your analysis. So we went to look at other blazers we have in our data and see if we can find more evidence of these kinds of

I'm Ira Flato. This is Science Friday from WNYC Studios. Talking with Dr. Chad Finley, Associate Professor of Physics at Stockholm University and Stockholm, Sweden, about this new finding of a neutrino. Okay, so you have, we have all kinds of tools in astronomy now. We have telescopes that can see infrared, ultraviolet, x-ray, gamma-ray, gravitational waves, and now we've got neutrinos. Yes. How do you put all that together to get a better picture of what the universe is looks like or should be or what it's made out of? Yeah, sure. I mean, that would be the most amazing thing is if you eventually will see something

in every single one of those messengers. And so that hasn't happened yet. We have the gravitational waves were first seen sort of by themselves, and then they were seen last year with this, where there was electromagnetic, you know, radiation at the same so people saw light and gamma rays the same time. But we didn't see neutrinos at that time. Seeing all of those things from one object may be, it would be fantastic, but it may be asking too much.

But what's happening right now is that a lot of these tools are, for each sort of question you want to ask, there's a subset of these tools that work the best. So there's a good connection between, let's say, looking for gamma rays and looking, for gravitational waves, there's a good connection. If you want to, from, this happens usually that gravitational waves will come from things that merge, two black holes slam together, two neutron stars slam together.

That's the kind of thing that makes a very intense gravitational wave emission. And so that's what gravitational wave detectors are good for. For these blazers, you don't have the same, as far as we know, you don't have the same sort of dynamics of two masses coming together. So it's not expected that you would get strong gravitational wave signal from blazars. So this is where neutrinos would come in. Neutrinos together with gamma rays and x-rays and radiance. Interesting.

I know you've worked on this for a decade, right? Did you imagine you'd ever get to this point? What does it feel like now? Yeah, well, you do and you don't. Yeah, I mean, you certainly start with optimism, and then at a certain point you're wondering if you are ever going to see anything. So, I mean, there's the moment where these things start to connect. And I think myself and others found it hard to believe.

We'd never seen something like that before where things seemed to fall into place. So there's a lot of going back and checking and rechecking and trying to make sure that you really have all the evidence solid and fitting together. But, I mean, it's tremendously exciting to. to get to this point and start to feel that with this lead, you actually know where to go next. Yeah, and which is? To go back, the first thing, I mean, the thing we're doing now is going back in our data. Yeah.

And looking for more evidence they may already have. And then the next steps are we have, there's a plan. We have an idea of how we can improve already the data we have with an upgrade that can, The main thing we've learned running the telescope for 10 years is how much better we can make the telescope. That's always better. You're going to upgrade it and see where you go from there. Unfortunately, we've run out of time, but please come back and talk more with us, Dr. Finley. Chad Finley, Associate Professor of Physics at Stockholm University, also former a leader for Ice Cube's Point Source Analysis Working Group.

We're going to take a break. Bookworms. Science Friday Book Club is back. It's a classic bestseller. Stephen Hawking, you know what book I'm talking about. We'll be back after the break. Stay with us. This is Science Friday.

I'm Ira Flato. This spring, physicist Stephen Hawking passed away, and of course he's remembered for many things, including his poetic descriptions of the often technical work of physicists and other sciences. Here he is on Science Friday back in 2013 when I asked him if he thought there were any questions we might never answer.

I believe there are no questions. that science can answer about the physical universe. Although we don't yet have a full understanding of the laws of nature, I think we will eventually find a complete unified theory. Some people would claim that things like love, joy, and beauty belong to a different category from science and can't be described in scientific terms, but I think they can all be explained by the theory of a very.

Revolution. It was Stephen Hawking back on Science Friday in 2013, and in his honor, what better book for your summertime reading list than a brief history of time? Hawking's groundbreaking work of cosmological communication. It is our choice for our book club. Science Friday producer and book nerd in chief, Christy Taylor, is here to tell you more and explain how you can participate. Plus, introduce you to our guests. Welcome, Christy. Hey there, Ira. So, to get you excited about a brief history of time, this is actually something our readers from our last book club, which you may remember was Frankenstein.

Our readers from that last book club weighed in on what they thought we should read next, and it was a brief history of time to celebrate the life of Stephen Hawking. But also, it's the 30th anniversary of its publication in 1988. It was cutting edge at the time. It asked all these big questions that sparked people's imaginations. How does the universe begin? How does time seem to flow in one direction, even though maybe there are some reasons why it should not? And other dimensions, things like that.

It was a real groundbreaking work, and we want you to read it with us. So the first thing that I want people to know is that you can get a copy for free on our website at sciencefriiday.com slash book club. Jump in, sign up. We will pick 20 lucky winners. And then if you don't win, you can get a discounted copy from Powell's books.

because they are generously donating such things to us, as always, and start reading with us. We will talk about it today. We will read for six weeks and then jump back into the conversation with our guest readers at the end of August. And those readers are here today. And they are? They are.

Great question, Ira. They are two people who both think deeply about the universe as it is now and are also science communicators to some degree as well. So we have Priya Naderajan, who is a... professor of astronomy and physics at Yale University and the author of Mapping the Heavens, which is all about some of those big ticket cosmological questions. She joins us today. Hi, Priya. Yeah, hi, Christy. Hi, Ira. Hey there. And then we also have Clifford Johnson, who is another fantastic professor of physics and astronomy at the University of Southern California. He's the author

of that great comic book about cosmological questions, the dialogues, which sort of breaks it down into really cool and accessible visual representations. And he also joins us today. Hey, Clifford. Hi, Ira and Christy. Pleasure to be here. Thanks for coming. So we're just going to dive into a little bit of why we should be excited to talk about

this book right now. Priya, when did you first read a brief history of time? So I grew up in India, but I was in college at MIT when the book actually came out. And I was actually back home in Delhi that summer. and, you know, I had to resist getting a pirated copy in paperback because I hadn't bought the hard back. So I promptly came back from India back to Boston and bought my first copy. And it was deeply, deeply influential, especially, I think, the chapter on Blackholds, as you can imagine, right? It set me on a journey of falling in love with Blackholds and has really shaped my scientific interest over all these years.

And Clifford, you re-read the book for us just this week. How is it aged since graduate school? I think it's aged pretty well. I think it's still extremely striking as a book that, like nothing before it, I think, put a huge amount of what I considered, very esoteric and mathematical sorts of concerns alongside concerns that we can all get to grips with, you know, how does time work and how this universe work, what have you. put them together in this really great way. There's some things in there that are a little bit dated, but I think the core of the book is still very sort of sparkling with freshness. Ira, we asked our Twitter listeners if any of them had read the book before today,

and some 40%, so about 250 people responded, and only about 40% had read it. There's this joke that a brief history of time is one of the most purchased, never read books of all time. It sold like millions of copies in the next. 90s. I read you read this before. You know, I read parts of it, but not the whole thing.

You're right. It was said that it was the greatest coffee table book written. No one wanted to admit that they didn't read it, but they had it in their home. And in rereading it and reading parts for the first time, I'm just struck by two things. One is what a great communicator, Stephen Hawking was. I mean, how he could break down stuff into complex material but make it sound very simple, big ideas and very simple. And two, how the, I've been reading now these books for 30, 40 years, but forgetting how he laid the groundwork with the terminology, with the, you know, the basis for what we now read in books later to come, even some of the drawings. We're there in the first book.

So it's still fascinating now. Tell me about those drawings, Ira. I mean, there was this light cone one, you know. It looks like, right? It looks like an hourglass when you look at it. I've seen it in current books, not realizing that Steve. even had put it in that book 30 years ago. Yeah?

So it's, and then also about, when you put, when we talk about quantum, they give numbers, spin numbers to it. I never really understood what the spin number actually meant. And he gives a very simple explanation about what the spin means. It's just beautiful stuff. Yeah, I was going to say, I really like his sense of humor here and there. I mean, he introduces the book with, I think it's a now famous analogy about turtles all the way down, which I don't know, Priya, if you can sort of connect to that. that to how we talk about physics.

Yeah, no, I think that there's a way in which he came up with analogies to give a sense for these cosmologically large numbers to kind of make them tractable. And also talk about, you know, the concepts, the really complex concepts that we really didn't have a scientific explanation for. So for causation, for example, when people talked about, you know, he talks about how when we think about the origin of the universe, right, so we don't yet have a fully scientific explanation. We are still working, and he had this analogy of how we could kind of keep reducing it and say, well, it's turtles kind of all the way down, right, holding things together.

And I think that, you know, coming back to the point about him being, you know, his stature as an international ambassador for science, you know, I agree with Ira that he was sort of the original. He was the first guy. He believed so strongly in the need to communicate. And I think it's his legacy now that there's so many of us who've realized how important it is to bring science to the public. You know, I happen to be at his service of Thanksgiving in his memory, which was held at Westminster Abbey, last month, where his mortal remains were interred between the graves of Newton and Darwin. And it was a really, really moving occasion.

and I think his stature and how he touched people was just incredible, right? So there were 1,000 members of the public who were going to be invited to this ceremony. And the Hawking Foundation said that there was a lottery by which they were selected, and 27,000 people from around the world had applied to be there. Yeah, sorry, go on for you. No, I think he was, you know, he's definitely one of the most influential communicators of science. And, you know, really firm believer that, you know,

it's really important to share the awe, the curiosity about the cosmos with the general public. Yeah, Clifford, when Hawking passed away in March, it very much felt to me like more people knew him as this famous, this famous person, this scientist who was famous. He was on the Simpsons, he was on Star Trek. He gave all these lectures. He had written these books. What about his actual research?

Do you think people really know what he contributed to science? Well, I think most people don't. And I think one of the things that makes him quite singular, well, at the time, was while there were massively popular people like Carl Sagan as well, I think they were very much perceived as maybe, rightly or wrongly, having stepped aside from research to do their popularization. Whereas he, I think people understood that he was still helping drive the field at various points. But that doesn't mean that they knew exactly what he did.

One of the very striking things is that I and many, many researchers like me are writing equations in our notebooks right now. In fact, I'm looking at one of my notebooks. And there are things in there that go directly back to his amazing work in the late 60s and early 70s on the quantum nature of Black Hulls and things like that. And he really sort of helped change the entire language of the field and point up some crucial things. And that really is a legacy that will be there whether or not he ever had written this book.

And so that's quite striking. I mean, Priya, what do we know about Black Holes, thanks to Stephen Hawking? Yeah, I think one of the most significant contributions that he made was that, you know, although we, we, no black holes as these monsters from which even light can't escape, he realized that black holes actually give off thermal radiation. So this is not stuff that's coming from inside the black hole, but stuff that's coming from right around the periphery from the event horizon. And this radiation

is referred to as hawking radiation. It's at very, very low temperatures for the black holes that we have evidence for, like, you know, the stellar mass black holes that were recently detected by LIGO, the collision of these black holes and the gravitational waves, or the kind of supermassive black holes at the center of our galaxy and others that people like me work on. So the significance of this work was not so much the effect itself that the radiation was coming out, but the fact that he was able to provide a rather clear-cut physical sort of implication that brings together these two major theories in physics, this general relativity and quantum mechanics and this sort of marriage that includes deeper notions from thermodynamics. So this idea

of black hole evaporation, although it's not particularly relevant in terms of how long it takes, it takes an eternity for the kinds of black holes that we love and know and have observed so far. But this sort of attempt to bring this theory of the largest scales, general relativity, combine it with a theory for the smallest scales in this one instance. around Blackholes is phenomenal. And, you know, this deeper connection and a more overarching theory is something people are still sort of searching for.

But this was an illustration of, you know, one setting where these two theories could really be powerfully combined. I mean, I think, you know, this work on Blackholes for me, look, this book is just absolutely wonderful. It's exhilarating to read still, right? But I think it's the chapter on black holes, and I keep saying, right, Chapter 7, I mean, that did it for me. And I think a lot of people of my generation, right, he really debuted Blackholtz for the public with this book.

And for me personally, sort of my reaction, when I read this, you know, especially Chapter 7, immediately went back to MIT, took a graduate course in gender volatility that was taught, incidentally, by one of his former students, Nick Warner, using his notes. So, you know, I think it's been deeply influential to share his work both for people pursuing science and academic science professionally. But definitely for the public. You know, his descriptions, as IRA mentioned, those lovely diagrams, as simple as they were, right, not complicated, fancy graphics like we have today, but they convey a lot of the ideas and the conceptions. I'm Ira Plato. This is Science Friday from WNYC Studios. And we have to wrap this up in the next few minutes.

But Clifford, in our last segment, we were talking about the recent neutrino discovery, which traced high-energy neutrino right back to this black hole called a blazar. This is exactly the kind of discovery Stephen would find exciting if he were still alive, right? Yes. You know, it marks the coming together of many different kinds of physics, which also, I think, is an earmark of Stephen's work. This is part of what people are now calling, and maybe that was mentioned in the previous segment, multi-messinger astronomy where we're seeing different ways of looking at the sky, not just optical telescopes,

but looking with neutrinos, and as, as Priya mentioned, looking with gravitational waves. We're seeing those different things come together in concert with other ways like telescopes to really change how much we can learn about the universe, possibly in a very revolutionary way. So being able to tag neutrinos and associate them with particular astronomical events in the sky is the beginning of a whole new lever we can pull to understand how the universe works.

This is completely what Stephen would be excited about. Great. Well, thank you both so much. Ira, I hope this has wedded your appetite to finish reading the book. Absolutely. Great. So in order to encourage everyone else, to participate. Again, we are giving away 20 free books, thanks to the generous donation by Powell's

Books. And everything that you need to know about participating will be on our website, ScienceFriiday.com slash book club. Enter the giveaway. That will close by Sunday night. We will also have a link where you can buy a discounted copy from Powell's books all book club long. And then there's a whole bunch of other stuff there. You can sign up for our newsletter, which will come out every Tuesday with extra resources for listening or for participating and learning and reading. We have a special call out to artists. We are commissioning art based on some of Stevens' really fantastic analogies. We will pay you.

Also, again, science Friday. Real money, not just science dollars, which I don't know what those are, not neutrinos. And so we are calling out to artists to help us visualize these great words. We are having an event in New York City at the end of August, a time travel. cocktail party in honor of Stephen Hawking having thrown one himself a long time ago. We are sending out the invitations in advance, unlike Stephen. And then we also have a voicemail line. So that's 567-243-24-6, where you can call with your questions, your comments, your reactions,

anything that crosses your mind as you're reading. And, of course, we are always on Twitter, hashtag SciFri Book Club. How long is this going on? This is going on until the end of August. Six weeks, August 24th is our wrap-up conversation with Priya and Clifford. We'll have more of the same great discussion you just heard. Thank you both. Thank you all three of you for taking time to be with us today.

Priya Natarajan is Professor of Physics and Astrophysics at Yale University. And Krovor Johnson, Professor of Physics and Astrophysics at the University of Southern California. Also author of a great book of The Dialogue. And Priya has written The Mapping the Heavens. A couple of great books to add to this reading list also. As we're saying, we're reading Stephen Hawking's Brief History of Time, and joining us back on the air, August 14th, to discuss in depth, back with our panel to talk about the book when it's all over. Charles Berkowitz is our director, senior producer, Christopher Taliaata.

Our producers are Alexa Lim, Christy Taylor, Katie Heiler. Our intern is Lucy Wong, and we had technical engineering help today from Rich Kim and Sarah Fishman, and we are active all week on Facebook, Twitter, Instagram, all social media, and if you have a smart speaker, you can ask him to play Science Friday whenever you want. So every day, considering all our social, community and everything else. Every day is Science Friday. I'm Ira Flato in New York.