← All Of It with Alison Stewart
All Of It with Alison Stewart
A Space Science Roundup With Brian Cox
00:24:11
Particle physicist and science communicator Brian Cox takes questions on the nature of the universe.
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Alison Stewart
This is all of it on wnyc. I'm Alison Stewart. And to close out today's show, we're talking about outer space. And February is a big month for space happenings. This year marks the 100th anniversary of the discovery by Edwin Hubble that there's more to our universe and there are other galaxies out there besides our own. February also marks two anniversaries of space missions to space missions to study the sun, which we're seeing more and more of since the Soltis and December. And later this month, we'll be stargazing opportunity that we won't have again until the year 2161. It's called the Great Planetary Alignment, or less formally a planetary parade. And with all that, we thought it was time for a space roundup. To Joining me now to share his expertise, please welcome physicist Brian Koch, who studies particle physics at the particle accelerator at CERN in Switzerland. He'll be touring his live show for the first time in the US in the spring. It's called Horizons A 21st Century Space Odyssey. We'll hear about that as well. Brian, thank you so much for being with us.
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Brian Cox
Pleasure.
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Alison Stewart
Let's start with I'm calling this Sun 101. We'll talk about the axial tilt. Am I saying that right?
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Brian Cox
Yeah, that will do.
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Alison Stewart
It'll do. All right. Can you explain the Earth's axis is tilted and how that creates the size, the seasonal climates that we expect?
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Brian Cox
Well, yeah, the seasons, I always think they're a wonderful thing because they're evocative and we all know what they are. So obviously we're in the winter now and it snows, and then summer it's hot. But this manifestation of the geometry, the arrangement of the solar system. So of course, the Earth goes around the sun once every year, but the Earth's axis is tilted about 23 degrees or so. And that means that at some points of the year, if we're in the northern hemisphere, the northern hemisphere is pointing towards the sun and at other times is pointing away from the sun. Now why is the axis tilted? Well, it's tilted, we think because the Earth got hit by something very early on in the in the history of the solar system. So four and a half billion years ago, which knocked the Earth over. And so you realize that this gentle passing of the seasons is telling you that you're on a tilted spinning ball of rock tearing around a star and the Earth. The radius of the Earth's orbit is about 93 million miles away or so from the sun. And so it's going very fast around the sun. And we're obviously once a year. So I like the fact that it reminds every time you see that snowfall or the leaves fall off the trees in the, in the fall, you can imagine why that is. And it's a history going back four and a half billion years. And it's a story of big lumps of rock orbiting around the nuclear fusion reactor.
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Alison Stewart
That's a beautiful way to put it.
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Brian Cox
Yeah, it's, it connects us with the, with the, the wider universe that we don't always, I don't think we're always a. You know, it's not natural to think you're on a ball of rock tearing through space because we don't feel it.
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Alison Stewart
Sometimes it's natural. Sometimes you just think I'm a dot.
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Brian Cox
Yeah, I do. Sometimes I guess I'm a very tiny dot. I mean, the sun, you can fit a million Earths, roughly speaking, inside it.
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Alison Stewart
Yeah.
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Brian Cox
So although it's a kind of small thing in the sky because it's over 90 million miles away, a million Earths inside it is a big thing.
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Alison Stewart
Actually, I'm a smaller dot. Let's talk about the two launch anniversaries that are related to the study of the Sun. On February 5, 2002, NASA launched HESI to study solar flares. And then on February 10, 2020, I believe it was, NASA launched the Solar Solar Orbiter. Could you walk us through both of these anniversaries, how they've helped us understand the sun?
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Brian Cox
Well, yeah, and there's a. Your question is really a good one because the deeper point, you might think that we understand how the star works. And we, we sort of do in broad terms. But even that it's only the last hundred years or so. You go back a century and there were people calculating how long, what the lifetime of the sun would be if it was burning coal, because we didn't know about the atomic nucleus. And if you don't know about nuclear physics, which is a 20th cent rediscovery, you can't understand how something could emit so much energy. And yet. And we knew how far away it was that was measured in the 1700s. So we, so it was one of the great conundrums actually. So solar research itself is, is only about 100 years old, but it's now we're interested in questions about how stars work in detail. And again, you might say, well, does it really matter? Does it concern us? Well, it does, because solar flares, for example, that you mentioned, they're eruptions from the sun, they're to do with its magnetic field, which we don't fully understand by any means, but they reach the Earth and we see them as aurora. So again, experiencing, when you see the aurora borealis, the northern lights or the southern lights, you're seeing eruptions from the sun, charged particles from the sun interacting with the Earth's magnetic field. They're important. They're not only pretty and a beautiful thing to see in the sky, but they can affect communication satellites. At the largest that the biggest solar flares. There was one called the Carrington flare, which was Sometime in the 1800s, I can't remember the exact date, which is a huge solar flare. We saw aurora in Hawaii. So, so it was, if such an eruption happened today, now we have modern technology and communication satellites and so it would be tremendously disruptive. And so we want to understand better those solar storms, those eruptions from the sun, because they have a direct impact on us and potentially it can be quite a very serious impact actually.
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Alison Stewart
And those are the ones. It's an 11 year cycle.
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Brian Cox
Yeah. So the sun has an 11 year cycle. We don't really fully understand that. Sometimes it's not, not as active, sometimes it's more active. Its magnetic field flips around. The Earth's magnetic field flips around, but on hundreds of thousands of years time scale, the sun does it on a few, it's decades. So again, it's, it's interesting to me that we don't, we don't fully understand by any means how our near, how our neighboring star works. And that's what these missions are doing. As I said, some of it's just pure curiosity. We want to understand how stars work, but some of it's space weather and space weather is actually important.
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Alison Stewart
When you think about the Solar Orbiter mission, it's scheduled to go through 2026. It can be extended to 2030. If you could, if you could have a say in it, what would you want? What questions would you want answered?
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Brian Cox
Well, it's those, it's those fundamental questions about stars, about the way that they're, that they're big spinning magnets in a sense. So why are they big spinning Magnets, how does that all interact? How is it that these, these huge eruptions of energy form and, and sometimes affect the earth and sometimes don't. And so that there are still there are practical questions. And I think it's interesting as we, as we go further out into space and become more reliant on space and we're already, we all use satellite navigation and communications and weather forecasting and earth observation and so all those things. But, but as we get more and more involved in the space economy, we're going to become more reliant on it. So I think it's I. The study of stars, it's a beautiful example of the wider sort of question of why we do science. So ultimately we do it because we're interested, so we're interested in how stars work. Curiosity. But also it tends to turn out that the study of nature, finding out more about the way that nature works is useful to us. And it's worth reminding ourselves sometimes that this, this what might seem like rather esoteric questions often lead to tremendous advances. And in this case just understanding the way that the, the environment up there in space works.
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Alison Stewart
I remember I interviewed a scientist in their lab and she says, I just ask questions.
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Brian Cox
It's the, it's the way that it precedes one of my great heroes, Richard Feynman, very famous Nobel Prize winning scientist. He used to say that, you know, you, you ask very simple questions. Those are the only questions we can answer actually. So we don't have, we can't answer grand philosophical questions about the, the meaning of it all and the, the origin of the universe and those things. We're not at that level yet. But by asking very simple questions, it could be why is the sky blue? Or what is the aurora or you know, why is there oxygen in our atmosphere? Those kind of questions, you're led to a deeper understanding of nature that can then sometime quite profound ideas. You mentioned Hubble, the anniversary of Hubble, Edwin Hubble showing that these so called nebulae in the sky, the misty patches that we'd seen in the sky for a long time since the invention of the telescope, and actually the Andromeda Galaxy, our nearest neighboring large galaxy. You can see with the naked eye in the right conditions. So it was known this little patch was there. What is it? It's a remarkable discovery that he made building on work that had been done for, for many years. But a great astronomer called Henrietta Levitt did a lot of work on these particular kind of stars called Cepheid variable stars. And he used that work to measure the distance to this misty patch and found that it was outside our galaxy. We now know it's two and a half million light years away, which is the modern number for that measurement. But what a remarkable thing. How do you measure the distance to a star, never mind the distance to a galaxy? And it's so it's a long ultimately, by the way, it begins by measuring the distance of the Earth from the sun. So without that, you can't measure the distance to the stars. And that was it all comes back to the sun. It does. And so you need to know the distance of the Earth from the Sun. And that was in the 1700s as well. So it's quite relatively recent, actually, that we've understood that these things are far outside our own galaxy.
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Alison Stewart
My guest is physicist Brian Cox. He's joining us to talk about the latest space news as well as about his Show Horizons A 21st Century Space Odyssey, which will be coming to the US this spring. Check online for shows and tickets. By the way, I'll turn over my microphone to our listeners. If you have questions about space or the nature of the universe or anything else you want to ask Brian Cox, give us a call now. 212-433-WNYC, 212-433-9692. We'll be right back.
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Brian Cox
This is Ira Flato, host of Science Friday. For over 30 years, the Science Friday team has been reporting high quality science and technology news, making science fun for curious people by covering everything from the outer reaches of space to the rapidly changing world of AI to the tiniest microbes in our bodies. Audiences trust our show because they know we're driven by a mission to inform and serve listeners first and foremost with important news they won't get anywhere else. And our sponsors benefit from that halo effect. For more information on becoming a sponsor, visit sponsorship.wnyc.org.
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Alison Stewart
You are listening to all of it on WNYC. I'm Alison Stewart. My guest in studio is physicist Brian Cox. He's joining us to talk about the latest and about his live Show Horizons, a 21st century space oddity. I want to know about the show. What do you cover in the show?
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Brian Cox
Well, I mentioned before the break that science you start with simple questions and then sometimes it led to rather grand questions. So in that I asked the question at the start, actually, once you consider the size and scale of the universe, and we mentioned the Andromeda galaxy, in fact, two and a half million light years away, we now think there are something like 2 trillion galax each with hundreds of billions of stars in the universe that we can see. And so questions arise. And I say at the start, you know, when you consider cosmology, you think, what does it mean to live a finite, fragile life in an infinite, eternal universe? Which is a very good question. And I point out, I don't know the answer, so don't buy a ticket. If I knew the answer, I'd charge a lot more for tickets. Right. But it's remarkable how much progress we've made in. In trying to understand why is the universe the way that it is? Why does the universe allow life to exist? I talk about life in the show. It's easy to dismiss, again, as we said before, the fact that we are. We take for granted that we exist, but we're just collections of atoms. The great Carl Sagan once said that a physicist is a hydrogen atoms way of learning about hydrogen atoms. And so you say, well, how can it be that the universe 13.8 billion years ago is just full of hydrogen and helium, the simplest chemical elements? 13.8 billion years later, there are collections of atoms like you, us, you and me, and everyone that's listening that can think and learn about the universe and consider these great existential questions. What properties of the universe allowed that to happen? And what do we know about those properties? And so, quite immediately after, we've done a tour of the universe, and I should say there are huge LED screens, as much as we can fit in the town hall here in New York, and I was down there yesterday, actually, you can fit a lot of LED in there, so it's going to be great. But you see these pictures. But then quite quickly, because I'm interested in these questions, we start to talk about the origin of life, the evolution of life. Questions like, well, how many civilizations might there be in a galaxy like the Milky Way? My guess is there might be very few. In fact, my guess is, and it's a guess based on the history of life on Earth, there might be one which would be us. And then you get an interesting question about, well, how, notwithstanding our physical insignificance, we're little dots on one planet, around one star amongst 400 billion stars in one galaxy, almost 2 trillion galaxies in the observable universe. Notwithstanding that, imagine that this is the only place where a civilization currently exists. Then suddenly this little rock is tremendously valuable. And so we talk about that. And so soon we're off into sort of rather more profound terrain.
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Alison Stewart
We actually have a question about that. Let's talk to Tierney from Putnam Valley. Hi, Tierney, you're on the air.
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Brian Cox
Hi. How's it going?
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Alison Stewart
Okay. What are your thoughts?
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Brian Cox
I wanted to ask if.
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Progressive Insurance
I wanted to ask if you think.
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Brian Cox
That there's a chance that we are living in a simulation. It's a great question. And the answer is that I have no idea. Because the question, the scientific question becomes how would you know? And what I would say is that I can see nothing in the laws of physics that that would rule that out, but I also see nothing that would rule it in. So at the moment it become. In scientific terms, it would become. The question would be, could you make an observation or do an experiment or learn something that would tell you that you live in some kind of simulation? The last thing I'll say very quickly is there is interesting evidence from. We're trying to understand at the moment what space and time are in physics. And it turns out that we. One of our pictures of space and time is that they emerge from a deeper structure which looks a bit like a quantum computer. So that would not be evidence that we live in a simulation. It just might say there's a description of the universe that looks a bit like a quantum computer. But it's. So I. That's what I would say to you. The answer is, nobody knows. And the really interesting thing for the challenge to you and everybody else that's thinking about it is what kind of an observation would convince you that we are.
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Alison Stewart
Let's talk to Ed, who is calling in from Clifton. Hi, Ed. You are on the air with Brian Cox.
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Progressive Insurance
Thank you so much. My question is 50 years ago, exactly. I was in a freshman in college, and due to the inquisitiveness that you spoke about, I took an astronomy class. And in that class, the most interesting thing that I recall is they talked about quasars, and they didn't understand how a quasar could exist because they were too bright to be at the distance that the red shift indicated they should be at. And it was a puzzle. And since then, I've never really heard an answer. And it seems you don't hear about quasars anymore. So I'd like to understand that better.
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Brian Cox
Yeah, it's a great question because you say they weren't discovered so long ago. So for everybody listening, they're very, very, very bright sources of radiation energy in the centers of galaxies very far away. So we're pretty sure. I mean, I'd say they are associated with supermassive black holes. Now, supermassive black holes, 50 years ago, we didn't know that we, we had very little evidence that these things existed beyond theory. So they were kind of predicted from Einstein's theory back in 1915, but we didn't have good evidence for them. Now we do. So Nobel Prizes have been awarded for the discovery of these things. And we have a photograph of one which is in the center of a galaxy called M87, which is 55 million light years away, which is 6 billion times the mass of our Sun. So we talked about the sun earlier, and I said, you can fit a million Earths inside this thing. There's a black hole in the center of that galaxy that's 6 billion times more massive than our Sun. And so these are tremendous sources of energy. But the exact mechanism, you're right about it, to do with the way these things interact with the wider galaxy, I think it's. This is not exactly my area, but I think it's fair to say the exact mechanism is still a source of research. But I also think it's fair to say that it's certainly associated with these incredible supermassive black holes.
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Alison Stewart
I want to get back to one more thing that's going to happen this month, February 28th. They're calling it the planetary parade. Okay? It's Saturn, Mercury, Neptune, Venus, Uranus, Jupiter and Mars will be sort of in the same region in the sky. Explain to us the significance of this event.
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Brian Cox
It's significant aesthetically, right? It's very beautiful. And it's just to do with the fact that from our vantage point on the Earth, when we look out, the planets are at the right place in their orbits around the sun such that they line up in our sky. So there's no, there's no significance that it doesn't do anything to us. It's just a. We're just looking out into the solar system and it's moved into this arrangement. But it is tremendously beautiful because you can see. So the brighter planets, you can see Uranus and Neptune. You can't see it unless you have a telescope, but you'll see Saturn and Jupiter and Mars, and it's worth looking at them. Mars is obviously red. So the moment you know what you're looking at. So you could get one of those apps on the, on the phone that are free to get and just, just identify them because then your mind can be transported. So even if you have a small telescope, you can see the rings of Saturn and the clouds on Jupiter. But even if you don't, just with your eyes, you can see these worlds. You can see their different colors and then you can start to think that Mars is this planet with polar caps on the. And it's got. It probably almost certainly once had oceans and rivers in orbit around Jupiter. So you look at Jupiter, this point of light, if you have binoculars, you'll see it's moons, it's brighter moons. We have two missions on the way to those moons, in particular a moon called Europa. Europa. So you can let your mind wander. Europa is an ocean world with a frozen surface, with a saltwater ocean. And there's more water in the ocean than in all the oceans of the Earth combined. So we think it's a possible habitat for life. So we have two spacecraft in flight going there. So, so again, you can let your. I think that one of the beautiful things about astronomy is that you can, you don't need any, anything other than your eyes and just you can familiarize yourself with the sky. And then the more you know about the points of light that you're looking at, the more magical it is.
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Alison Stewart
This text says what was here before the Big Bang according to its theory and what did it look like?
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Brian Cox
So we have a theory that the Big Bang was something that happened in a pre existing universe. It's a theory called inflation. And so the idea is that before the universe was very hot and very dense, which is what we call the Big Bang. And that's the thing we have a measurement back to. So we know that 13.8 billion years ago then the universe was very hot and dense. So the question is, is the caller said what happened before that? So there's a theory called inflation, that the universe was still around, space was stretching very fast, and that period in the universe's life came to an end. And in coming to an end, that's what kind of nucleated the Big Bang, if you like. And you might say what, how can you. What a ridiculous thing to say. But that theory, it was in 1980s, that theory was explored and it made some predictions in particular, a beautiful prescription, a beautiful prediction about how galaxies are distributed on the sky. So you might think the galaxies, when you look, we see thousands of galaxies. And you might think they're random like a snowstorm, but they're in fact patterns in them. And this theory predicted the pattern before it was. Pattern? Yes, before it was observed. So it's almost like there's a message written in galaxies across the sky which is telling us something about this early universe. So it's a very, it is the textbook theory, the thing I've just described called inflation. And the aim now is to test it as far as we can. And we have some tests and it's past the tests.
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Alison Stewart
Let's try to get Mark in. Mark, real quick, what's your question?
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Progressive Insurance
Oh, I was just. My question is about Planck length and the, the infant, the subatomic world and the universe. And when does, when is small? What's going to be the smallest object or can it be infinitely small?
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Brian Cox
So way back actually turn of the 20th century, Max Planck noticed that you can, you can measure the strength of gravity and you can measure the speed of light and you can measure something called Planck's constant, which is associated with quantum mechanics and the way that light is emitted from things and so on. If you get those three things which are really fundamental, you can construct the. A length, you can make them into something that you can measure in meters. And it's 10 to the minus 35 meters, which in English is 0.000 with 35 knots. One of the meters. Tiny length, but it seems to be really fundamental, a fundamental property of the universe. And I'll give you one example of how it's fundamental, which is if you look at a black hole and you look at this, this thing which has a. You can say, well, what's the event horizon which defines where this black hole is, where if you go inside that, you can't get out, the amount of information contained in the black hole is equal to the surface area of the event horizon of the black hole in square plank lengths. So it's telling us something fundamental about space and time and information. So I would say yes, the Planck length is the smallest thing we can conceive of and that has any meaning in physics. 10 to the minus 35 meters.
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Alison Stewart
My guest has been Brian Cox. Thank you for your time, Brian. His show is called horizons, a 21st century space oddity. It'll be coming to the US in spring. Check online for shows and tickets and I will meet you back here tomorrow.
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Progressive Insurance
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