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Man, Welcome back to Coast to Coast, George Nori with you. Marcus choundback with us. An award winning writer and broadcaster. He's based in London, England, formerly a radio astronomer at the California Institute of Technology in Pasadena. He's the author of a number of popular science books, including The Magicians, The Ascent of Gravity, Quantum Theory, Cannot Hurt You, We need to talk to Kelvin, and Solar System for iPad now. His latest book we're talking about tonight is called The
One Thing You Need to Know. Marcus, Welcome back to the program.
How have you been?
Hi?
Thanks George, It's great to be on the program. Thanks inviting me. I'm well, how are you? I mean? Unhappy Independence Day?
Thank you very much. Thanks. Calming down in France right now? Boy, what a mess?
Huh wow. It's very difficult to know. I don't know how much you get on your news in the US. It's covered a bit in Britain, but I think things are coming. My sister actually lives in Nant, which is in France, so I think they had a bit of trouble there, but she lives in a main new kind of rural country area, so hopefully it is quieting down.
Yeah, tragic story. Anyways, You've got your new book that just came out, right.
Yeah, it's published in the US today, So that's really exciting for me.
The one thing you need to know tell me about that.
Title, right, Well, basically it's about the one thing you need to know to understand a particular topic. So I've picked twenty one topics, things like relativity, the Big Bang, plate tectonics, you know, evolution, all this kind of stuff, and I've tried to think of what is the one thing you need to know from which everything else follows logically. So it's kind of a way of trying to make a lot of really complicated science and what.
Is that one thing we need to know.
Well, for each topic, there's a different thing. So if I were to tell you about, for instance, relativity, I'm side to relativity. The one thing that you need to know is that that light is uncatchable. You know, it's impossible to catch up a light beam. This was something that was realized by Einstein when he was just sixteen. He was imagining what it would be like to travel alongside the light, alongside the light beam, and he realized
that you would see something impossible. So he concluded that you could never catch up a light beam. And all of the stuff of relativity or that or the madness of relative relativity follows from that sentence. You know, if you were to someone must move past you traveling near the light, you would see their times slow down, and you would see them shrink in the direction of motion. So they would have looked like they were walking through treacle or walking in slow motion, and they would drink
like a pancake in the direction of motion. And we see this all the time when we accelerate particles, for instance, in particle accelerators like the large hadron collide. We see these effects of relativity. But they all stem from this simple idea that you cannot catch up light. So it plays the role of the cosmic speed limit. So I take things like this and I just you know, I take the sentence that you need, and then I kind of deduce from that all the consequences.
You've got twenty one great chapters in this book will digest some of them, and maybe by the end of this interview over the next couple hours, Marcus, you'll help us learn about the Big Bang, which I still don't understand.
Yeah, well nobody does really, Let's face, that's good to hear that. Well, we don't know. We know a lot, you know. So we can see that the universe is expanding, and we can kind of imagine it the expansion running backwards like a movie in reverse. And you know, we come to this point about fourteen billion years ago when everything was concentrated into a single location, which we call a Big Bang, and we see all around us the
heat of to glow with the Big Bang. So incredibly, the whole universe is growing with the afterglow of the Big Bang fireball. About ninety nine point nine percent of all the light in the universe is the afterglow of the Big Bang, and only point one percent, that's one thousandth of the light in the universe is coming from stars and galaxies. But of course it's not light that we can see with our with the naked eye, which is why we didn't spot it until two guys at
Bell Lads in nineteen sixty five. So the evidence that the universe began in a hot, dense phase and a big bang of exploded outwards and the galaxy is like a milky way of kind of coalesced from congealed from the cooling debris. That's kind of beyond doubt. But of course the questions you're you're wondering about are what was the Big Bang? You know, what drove the Big Bang? What happened before the Big Bang? You don't know the answers to those questions?
Will we ever right? Will we ever get the answers?
Marcus got I really hope, I really hope. So, I mean, I think we're in an amazing position at the moment. I think previous generations would would have killed to have the kind of information we've got, you know, I mean James Webb Space Telescope, And that's as James Webb's Space Telescope was launched Christmas twenty twenty one, and it's looking back to very very close to the Big Bang, and
it's already surprising us with its discoveries. You know, so we we we can look at how the galaxies began to can jeel out of the cooling stuff of the debris of the Big Bang, and we can kind of learn more and more about this this Big Bang picture so yeah, I think I think we I mean, the incredible thing is that we have a good chance of asking answering these ultimate questions, you know, like what happened before the Big Bang? What is space? What is time?
All these really really big questions. We have a good chance of answering them, maybe in the next couple of decades, you know. So that's an amazing position to be in the history of science because it's there's so many these incredible space experiments that are up there. You know. James Webb Euclid was launched, i think this week, and it's
trying to probe dark matter and dark energy. These are the two biggest mysteries in the whole of astronomy are the universe is filled with this dark matter stuff that doesn't give out any light, and dark energy, which doesn't give out any light and is speeding up the expansion of the universe. So that there's another chance that we'll well had, maybe in the next few years, to figure out what they are. So yeah, I think there is hope. There's hope.
Who are you structuring and going after with the book? The one thing you need to know, who do you want to read?
Who do I want to read it. I kind of aim it all on my wife's she's a nurse in Britain, you know, and she doesn't have any science background, so I kind of I kind of aim it at her. Really, you know, I was very lucky, as you pointed out, to go to caw Tech, and I was taught by a lot of really interesting people, I reach of women. But I want to communicate the kind of things I learned to everyone, you know, because I think when people understand how amazing science is, they realize, you know, that
it's a fascinating topic. And maybe at school, you know, they learned the whole and boring science, but actually it's really you know, when you tell them about what we know, it really fires their imagination. So my aim is really to communicate some of this stuff that I learned to everybody, really, anybody, even if you have no science background whatsoever.
Back in the eighteen fifty four, there was a scientists that not a lot of people knew about. Unie's Foot. Tell us about her.
That's right. So she was an American scientist called Unice Foot, and she's pretty much nobody knows her name, but she did an incredibly important experiment and it's such an simple experiment that any one could do it in high school, you know. So what she actually did was she got some glass tubes and she filled them with different gases. She filled one with oxygen, she filled one with water vapor, another one with carbon dioxide, nitrogen, all these kind of things.
And she's start thermometers in these sealed glass tubes and she put them in the sun, and to her amazement, the tube that contained carbon dioxide and the tubes that contained water vapor in there, the temperature rose dramatically. So she realized she was the first person to realize that these gases, I mean, carbon dioxide is a made there's hardly any of it in the in the atmosphere. I mean it's I don't know, it's a fraction, a very small fraction of one percent of the atmosphere of cambraxer.
So this gas that appears to have no be to be really unusual and really there's not much of it, was having this tremendous effect. So she made the she spentated in eighteen fifty four that changes in the amount of carbon dioxide might be connected with changes in the climate. So she was the first person in history to recognize what we now call the greenouse effect. And now an Irish physinessist three years later called John Tyndall made the
same discovery. And in all the history books we remember John Tyndall, and Unice Foot has kind of been written out of history. So we need to remember Unie Foot, the American scientist who basically discovered the greenouse effect.
Yeah, Unis is not mentioned in many high school books on science.
No that she should be. But this is really common that you get these women who make these enormous contributions and are completely forgotten. I mean, my favorite is the Celia Paine and she was English, but she went from Cambridge to Harvard in the nineteen twenties and they didn't I mean, I think she was paid on equipment expenses something like that. And she actually discovered that the Sun
was made of ninety eight percent hydrogen and the helium. Now, these are two gases which are almost nonexistent on the Earth basically because they're very light, so they float off into space. So Ever, since Greek times, people have thought that sun was made of iron, you know, because it looks like it looks like a ball of glowing iron. It glows orange, glows in a golden color, and so until then people have thought it that had. Her supervisor was called Henry Norris Russell was one of the great
American astronomers. He told her in her PhD thesis to actually write that her result was almost certainly wrong. But ten years later, when it was discovered that she was right, he mentioned her on about one hundred and page one hundred and fifty of a paper that he wrote, and he got the credit. But part of the Celia Pain basically discovered the major component of the whole universe because most of the universe that we see is hydrogen and helium.
I mean, all the elements that we're made of calcium and oxydshire and oh and all the things that are in our body are am I in a contaminant at the universe. So she was the person who basically discovered what the universe was made of.
Marcus, when I was young in school, very very young, our teacher said that the son's going to burn out folks in the four and a half billion years, there'll be nothing anymore. And I would go home really upset. I talked to my dad and my mother, and I would say, the son's going to burn out. We're all going to be gone. And I didn't comprehend what four point five billion years from now was.
And we've got plenty of time. We can sleep tonight.
We can, we can. But I don't know why the teacher didn't explain that part of it to us, Like four point five billion years, folks is a long time. We're just kids.
Well maybe they should have done. I mean, the interesting thing is that when people started thinking of this in the nineteenth century, they obviously thought the lump of the sun is a lump of coal, because in the nineteenth century it was an age which was driven by steam, so they thought it was a lump of coal. And they were able to look at a lump of coal in the grate, you know, and they could see how long it took before it burnt out, and they could
extrapolate to something the size of the sun. And the calculation showed that, in fact, it was only five thousand years that the sun would burn before it burnt out, which was not enough for anybody, you know, It wasn't really enough even with every guy called Bishop Usher, who was an Irish bishop who calculated from the Bible that the Earth was created on. I think it was twenty third of October four thousand and four BC, So it wasn't even enough for him, and certainly not for geologists.
You know, we know that mountains rise up out of the sea, and for the biologists because we know that organisms have diverged from a common ancestor, but that process takes a long time. But it's this thicker you're talking about comes from analysis of meteorites, you know, the builder's ravel left over after the formation of Sosis, and we can date them, and you're actually right. We find out what the Earth is about four point five billion years, which seems a long time, doesn't it.
It doesn't, it.
Does, Marcus. What does this mean in terms of a divine creator? When you think of all the different things, just just by reading your book, we talk about gravity, electricity, all these incredible things. There seems to be so much order in the universe to make all these things happen. Where does the divine creator come in on this? Do you think about that much?
A matter of choice? Really? Where you can I mean some of the great physessests in history, like Isaac were very religious. They believed that in figuring out how the universe was working, they were actually laying bare the mind of God. So actually incredibly Newton is one probably the greatest scientist in history, but most of his work was analysis of the Bible, alchemy, and hardly any of his work was actually science. But he thought these were all
ways of appreciating God. So he would he, you know, the lord of gravity. He imagined that God had imposed the law of gravity. So you see this throughout history. So you have scientists who don't believe and scientists who do. But it doesn't really make much difference, you know, because either you believe the universe is this fantastically incredible beautiful thing or you think it's a fantastically incredibly beautiful thing that God made, it doesn't really make a lot of
difference really. So but what we actually see is that laws of physics that we've actually discovered do actually produce the universe that we that we see around us. So, for instance, we kind of know what's what the universe was like very early on in a big band, because we can see the art to go with the big Bank, so we could we know what the universe was like within within a few hundred thousand years of the Big Bank.
We can run in our computers forward the history of the universe using the laws of gravity, you know, the law of gravity in the laws that we see, and it gives us the universe which is very similar to the one that puts around us, you know, with galaxies, the size of the Milky Way, and all the properties of the universe. So it doesn't appear to be any divine hand is actually needed. So that's why I say it's a matter of choice, really, And some some physicists
are or scientists are religious, and others are not. I mean, Eiseen used to make loads of statements that use the word God. He wasn't religious himself, but he used to say things like God does not play dice with the universe and all that kind of stuff. But that's that's so that's really as I say, that's that's you can or you can't. It depends on your your own belief really.
Sure do you think gravity is the glue that keeps everything together?
Well?
Gravity is that is the glue that keeps large things together. Because gravity, and this is one of the absolute mysteries of science, is one followed by forty zero strong weaker than the forced the electric force. That's holding together the atoms in your body. So that's ten thousand, billion, billion, billion billion times weaker. Okay, So that's a real mystery
why the electric force is so much stronger. But it turns out that the electric force comes in two types, So it says a repulsive type and an attractive type, and in your body, those two forces completely cancel out. But gravity only comes in one form. It's only attractive. So the more material you get, the more gravity you get. So when you get to a certain size a certain amount of material, gravity begins to dominate. And in our solar system, that size is an object about three or
four hundred kilometers across. Okay, So when you get beyond that, gravity is so strong it can gather everything, crash everything into a sphere. When you have less material and that it can't. So when you look out across the Solar system, everything that's less than three or four hundred kilometers across is like a potato potato shaped, and everything that's more than three or four hundred klometers across is a sphere. And that's because that's the scale of which gravity begins
to dominate. So after that scale, it dominates everything. So it dominates planets, It dominates stars, it dominates the galaxy, and it dominates the universe. So in a way, it controls everything that matters to us. But of course it doesn't control the physics in your body, because that's the electric force. But so yeah, yeah, it is the dominant force because it only comes in one form and it only gets strong the more matter. The more matter you have, the more gravity you have.
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