Heino Falcke | The Hidden World Above

Falcke:

The heavens declare the glory of God. I think people intuitively understand if you look at the sky and the stars, you understand there’s something bigger and deeper out there, and something that you will not be able to control or understand fully. That’s what black holes tell us as well. There’s something that we cannot, at this point, at least understand. They are almost modern, mythological objects, because they speak of the beyond, they speak of destruction, they speak of death. That’s what people think intuitively, even if they’re not scientists, they feel this. From that perspective, they are fascinated by it. 

Heino Falcke, Professor of Astroparticle Physics and Radio Astronomy at the Radboud University in Nijmegen, the Netherlands.

Stump:

Welcome to Language of God. I’m Jim Stump. 

When the news came out that the first ever picture of a black hole had been taken, our staff all got called into the conference room. That’s what happens when the president of your organization is an astronomer as Deb Haarsma is. Deb pulled up the pictures on the screen and we talked about why this was such an amazing discovery. Heino Falcke, our guest today, has been staring up at the sky since he was just a kid in western Germany. And then fascination and the desire to see further into the darkness of space, led him to be one of the leaders of the project that took that picture of a black hole. We talk about that accomplishment and other scientific topics from the book he has recently published. But Heino is also a Christian and believes not only that his faith and science do not contradict each other, but even that his regular contemplation of the mysteries of the cosmos has widened the possibilities of what his faith might mean. 

Let’s get to the conversation.

Stump: 

Heino Falcke, it’s good to have you here. Thanks for taking the time to talk to us.

Falcke:

Well, thanks. I’m glad I can be here with you.

Stump:

So where is here for you right now? Where are you talking to us from?

Falcke:

We are on the internet, aren’t we? You know, doesn’t matter where we are? No, I’m actually here, in a little city near Cologne, in Frechen, near Cologne in the Rhineland area of Germany in the west of Germany, somewhat near the Dutch border.

Stump:

Oh, nice. So this technological ability to talk to people in real time like this across an ocean is pretty remarkable. That’s some of what we’ll talk about in a bit. But first, let’s get to know you a bit better if we could. So where did you grow up? What kind of kid were you? How did you get interested in science? Give us a little autobiography in that sense.

Falcke:

Okay. Everything in one minute, I guess? Actually, I grew up where I am now, near Frechen. Actually. I was born in Cologne, and we moved here. My father was a doctor of orthopedic, medical doctor, medical doctor, my mother a teacher. We grew up in a Protestant church here, which is, this is a generally Catholic area. And this church while I am at is… you know, we only have Catholic and Protestants, we are not so complicated as in the US, having many different denominations. This was one of the first in this entire area, in the 1600s, actually. And that’s where the Protestants were sort of still surviving. In Cologne, they couldn’t. So, one part of my family has always been part of this church for a couple of hundred years actually. Think about it. 

Stump:

We Americans have this view of Europeans as not very interested in church these days. Was your family peculiar in that sense?

Falcke:

No, I think church is still part of social life in general. Of course, its influence on society is declining. It certainly was bigger when I was young, politically, socially, but it’s part of the fabric of the social society, civil society in Germany. That’s certainly true.

Stump:

So tell us a little bit more about your interest in science. So you said dad was a medical doctor? What were the experiences you recall as a kid that made you interested in observing the natural world and even eventually going into astronomy?

Falcke:

Well, the first thing I remember actually was the moon landing. It’s not the first one, it was one of the last, Apollo 15 I was a little kid, I think it was four and a half years old. I was more or less the only one still watching it because people got bored after you know what we did a moon landing last year, so you know, what’s so special about it? So all the kids were playing on the street and the parents were enjoying the sunshine. I was sitting inside, watching a black and white television and seeing people running around on the moon. I was totally fascinated, flabbergasted that this would be possible. Intuitively I knew this was a bizarre, enormous thing that was going on, people walking around on the moon. So I wanted to be an astronaut. I wanted to reach for the stars. My grandmother who grew up actually in East Prussia, what’s now actually even part of the Soviet Union. Sorry, Russia. It was part of the Soviet Union when I was a kid. Soviet Union doesn’t exist anymore. She had beautiful night skies and she was growing up on a farm and she wanted to be an astronomer, as a young woman. She wasn’t allowed to, her parents said, you have to do something that’s something that’s sensible, not astronomy, that’s nothing for a woman. She was allowed to study, she started studying English and other things. But her passion was for astronomy. So I think part of that she passed on to me a little bit. She took me to a local observatory. I saw Saturn and the moon and so forth. The first time you look through a telescope it’s always a special experience, isn’t it? To see all the hidden world. But in general, I was always curious. I can’t even say that this was the defining moment, I remember myself always being asking questions, Where’s this coming from, why is this? And generally being curious, reading a lot. Then when I was 14-15, I discovered the computer. Everybody now has computers. but at the time, this was really, really special. This was when you only had super computers, very fancy big things that NASA had and some of the big companies, and now they had become available, you could have them at home. The first thing I saw was a programmable pocket calculator, it just would program a certain formula. Wow, this thing would do what you tell it to do. Then I talked with my parents. I wanted one of these VIC 20, Commodore VIC 20 computers. I got it in the end, because they asked, What is this thing? And what’s the computer? So I had to figure it out. They thought, yeah, that’s a good thing. Okay, he’ll learn something. So I got this computer. I really dived into it, I knew everything about the computer, every bit and byte in this computer, I knew I printed the entire operating system, you know, decoded it printed out on paper, as a big stack of paper, you could do this at the time. It had a whopping three and a half kilobytes of RAM memory. If you think about that, I think it was expanded then to 16 kilobyte if you know how little that is, but it was just but it was a fantastic tutor. That computer because what you learn with computers is they do exactly what you tell them to do. I mean, that may not be your experience today with a computer, right? They do their own thing. But these computers were simple enough. Whatever they did was what you programmed them to do what you told them to do, they don’t do what you think they should do, they do what you tell them to do. That’s what programming is. Every error that the computer makes is your own error. It’s because you didn’t communicate properly with the computer, you didn’t tell it exactly what you meant. That teaches us to be very precise, to always question yourself, because every time I got upset and tried to throw the computer into whatever the bin, it was my fault. It was me not formulating things properly. That was, I think, one of my best teachers. Ever since I’ve been using a computer for everything I do in science, I tried to optimize everything I did in science. I did it by hand, typically, but then always had the computer redo it.

Stump:

So by the time you got to university, were you pretty well on this track toward astronomy and the computerized automated world that that has become?

Falcke:

Well, it wasn’t that automated yet. In the first semester I was one of the first to actually use computers for data analysis. That wasn’t so widespread. People would still write things down and columns on paper with a pencil. I was using the computer. It wasn’t quite clear, in my mind, what I wanted to do, because I was fascinated with particle physics as well. I was interested in the fundamental questions. I wanted to do fundamental science, the deep questions, where there’s something new to discover. And that was either particle physics — because that was really booming in the 70s-80s in the last century, really — but I recognized astrophysics is also interesting. There’s so many new discoveries being made, new telescopes being built, new insights and every time there was something new happening, astronomy was really just beginning, the beginning of the golden age of astronomy. I could feel that, and you could see that. I don’t want to insult any particle physicists, but you could feel that particle physics if I was gonna phase a long period of hard work with maybe not so exciting results. Because a lot of things had already happened. You had to build bigger accelerators in much bigger teams. In astronomy, individual people could make new discoveries and find new things. What I also realized was that already then black holes started to fascinate me because what I understood was that if you would think about a theory of everything, that was a big thing at the time, the equation of everything, the theory of everything. We had an understanding of particle physics and other things, but gravity was resisting. That was one force we didn’t understand well because we couldn’t rhyme it was quantum physics. That was already clear in the 80s and 90s. So I thought, well, that’s interesting. So there’s a really fundamental theory here, theory of gravitation, of general relativity of Albert Einstein, that describes a world that seems to work well. We have quantum physics that seems to work well. They don’t work together. You don’t have a theory of quantum gravity yet. And where this is most obvious and happening is near black holes. So even in my mind, black holes were already very fundamental for understanding physics.

Stump:

Let’s get to your book here a little bit — Light in the Darkness: Black Holes, The Universe and Us. It came out in German last year and translated into English published at HarperOne this year. I just had to read through it this last week. People in your discipline, I think, primarily apply their writing skills to technical articles for peer reviewed journals. What was the experience like for writing a book like this for the general public?

Falcke:  

It was actually a joy to write, I must say. It was my first book I wrote. It happened actually, at the beginning of the corona pandemic. So I was like, halfway through and pandemic struck, and many things were canceled. So I had a lot of time to actually focus on on the book. I had reserved time for it. Being able to tell a story and to write your story in a book was really a pleasure. Of course, I do have some experience, which we haven’t mentioned yet, I’m also a lay minister in our church, so I’m used to telling sermons, to giving sermons. I’ve been giving public lectures for 30 years of my life, going to little churches, to amateur astronomer clubs, whatever. So I’m used to telling stories. That’s what you also learn at church, in fact, to tell stories, and writing down your own story, and mixing that with a story of science, the way you’ve got to know it, of course, was wonderful. You don’t create a fantasy world, right? You try to describe reality, but this book is the world that you’ve experienced, and you can write it down and tell the story. At some point, also, that gets hard when you have to cut things out, or it would have been much bigger. Then the publisher said, No, that’s getting too long, you’re telling too many stories, cut them out here. Too many jokes, not so many jokes, it’s a German book. I was working together with a professional journalist, it was really a collaboration, which is something you learn in science. In fact, you don’t just write an article, you constantly get comments, and some people say, oh, that’s crap, take out this, and it’s constantly revised. You have to have a lot of patience these days to write a scientific article, because everybody has an opinion, all your collaborators. Then the referee comes and so forth. So an article is never done, you polish it, you rewrite it. So being prepared to work with a publisher with a co-author, that was new to me, that was much easier than writing a scientific article.

Stump:  

Well, one of the very nice features of your book is that it situates this achievement of producing a photograph of a black hole, or at least the shadow of a black hole, we’ll get to that in a minute. But it situates that against the backdrop of the historical development of astronomy and cosmology. And I think it’s hard to overstate the really remarkable change, the revolution really, in our picture of the universe and our place in it that’s occurred over the last century, or maybe 115 years we go back now. Can you give us just a taste of what we know about the universe now that we didn’t at the beginning of the 20th century?

Falcke:

Well think about 1915, that’s when Albert Einstein developed general relativity. We had a universe that was not even the size of our Milky Way, that was static, that existed since eternity, and would keep existing for eternity. Space and time were absolute, everything was determined. The universe was like a clockwork. If you just would know a little better, we could exactly predict how the universe would be what you would think perhaps, in the future, I don’t know. You could predict where the stars, where the planets are, but also how machines… how the entire state of the universe would develop. Then Einstein came along and showed that time and space are relative, they’re not absolute things that exist by themselves in a way, they are only the ones that we measure, and we can measure them differently. Then we discovered the mathematical solution of black holes by Karl Schwarzschild just a few months later. And then David Hilbert, a mathematician, calculates how light is bent around a black hole, light can go around circles, and we find that light could actually disappear with all information in black holes and never come back. People think, oh, that’s just crazy, it’s just theory. Astronomers start to look at the universe. They figure out, well, there is more out there. It’s not just this galaxy, there are other things out there. Maybe they are galaxies, maybe they’re like our own galaxy. And ten years later in the 20s, they find that’s true actually. They are galaxies, our universe is much bigger than just our own galaxy, our Milky Way. Then they figure out, in fact, it was a Catholic priest, that the universe is expanding. According to the theory of Albert Einstein, that universe couldn’t be static. If you just apply the calculations, then either this universe is collapsing, or it has to be expanding, or you need some mysterious force to keep just right. The universe should be dynamic and the universe would have a beginning. What a radical thought. People like Einstein or any famous physicist just hated that thought, that the universe would have a beginning. Then you have quantum physics, which is even weirder, which tells you, you can’t even know the state of every object because it’s just to some degree random. Certain things you just can never measure precisely enough. Then even later, you have quantum chaos theory, which tells you, you can’t even predict everything, even if you measure everything precisely. You cannot even predict where, in 20 million years, exactly the Earth will be on its orbit. So the universe from being completely understood, from being predestined, being determined, being in a way boring, becomes something that started at some point, becomes unpredictable, at some level, becomes where time space are changing, where there are limits to our knowledge. The Big Bang, which doesn’t tell us with doesn’t allow us to look into the beginning of the universe, we don’t know where it’s coming from. We have black holes we look into where we can’t know what’s happening inside. We cannot predict the future over long timescales, at least not for individual particles. Our worldview has completely changed. I think many traditional Christians are fighting the signs of the 19th century rather than having understood that the 20th century has completely changed that picture.

Stump:

Yeah, that’s interesting. So 1915, we thought we were in a cozy little universe about the size, smaller, you say, even than what we understand the Milky Way to be. What can you tell us about the size we believe the universe to be now?

Falcke:

I think the visible universe is about 80 billion light years across. The Milky Way itself, if you look to the center of our Milky Way, we know very exactly it’s about 27,000 light years that we are looking into the past as well and into the distance. We’re looking at the Andromeda Milky Way, the Andromeda Galaxy, at about 2.5-3 million light years away, something you can still see with your naked eye. That’s how far your eye can see it can look a few million years in the past by looking at the Andromeda Galaxy. Then we are looking at the Quasars, supermassive black holes in the early universe, billions of light years away that we see. And yeah, our universe has expanded. If you go back to let me just mention the closest, the moon. I’ve talking about light years, the moon is a light second away. The most nearby, the planets are light hours away. The sun is eight light minutes away. The stars are a few years too few 1000 years away. Well, and then you go out all the way to the farthest galaxy in the universe, tens of billions of light years.

Stump:

Let’s talk a little bit about black holes here now. Can you give us a sort of crash course on what black holes are? You said they were first posited as a sort of mathematical abstraction or a solution to a mathematical problem. Tell us a little bit more about that. Why were these things posited? What led to the positing that there is such a thing? And give us a bit more about what they are exactly?

Falcke:

They were posited because it was the most simple thing to calculate, to be frank. When Albert Einstein’s theory came out, Schwarzschild calculated, okay, how would space and time look like around an object where all the mass is just the size of a point. It’s not even extended, it’s just everything in a single point. Every physicist knows that this is essentially a mathematical trick. It’s just something that makes your calculations easier. Einstein said this couldn’t exist. Why did he say that? Because when you calculate this situation where all the mass is in one point, then you find that the curvature of space and time becomes infinite, the gravitational attraction becomes infinite, and become so strong that nothing can ever escape due to the force of gravity. In fact, even if you go away from this point, at a certain distance, which we call the Schwarzschild radius now, because he was the first to calculate it. That three kilometers from a black hole the mass of the Sun, then even light would not be able to escape, still at that distance from that point source. That means that not even light can escape, no form of information can ever escape, nothing can escape, no matter no light, no matter what you do. That would mean that there will be a region of space that’s inaccessible to scientific investigation, because you need to measure, you need to observe for something to be real. That is a bizarre thought, if you’d had such an object, it would for sure be real, because you’d feel its gravitational attraction very far out still. But the region directly surrounding it, you would fundamentally never be able to measure and see. So Einstein said this can’t exist.

Stump:

And there was no empirical evidence for these things at that time?

Falcke:

At that time, absolutely no evidence. Except that a few years later, Heber Curtis, an American astronomer, looked at this nebula called M87 which later became famous because we took the first image of a black hole in this galaxy. At that time, people didn’t even know this was a galaxy, right? They didn’t know this was 55 million light years away. They didn’t know there were thousands of billions of stars, they didn’t know it had a black hole in the center. And he saw a little streak of light coming out of the very center. We now know this is a plasma jet, hot gas is shooting out with almost the speed of light and is accelerated by the black hole. He knew nothing of that; he just saw this little streak of light in his photograph, so to speak. It was pointing towards a supermassive black hole, but nobody knew. So you had this theorist developing the theory of black holes, so to speak, purely mathematically, and you had an astronomer seeing something there and it was pointing to where the theory was real. And they didn’t really know. It took decades to figure out that these things had anything in common.

Stump:  

Well, according to the well developed confirmed theories you work with now about how common are black holes? How many would we expect to find in our galaxy, say?

Falcke:

They are widespread, and there are two different types of black holes: there are the stellar ones so that they come out of the end stages of stars, when the star has used up all its fuel, then there’s no pressure anymore, no heat anymore to keep it up, and it will collapse. In that collapse, if the star is really big, the pressure in the inside becomes so big, the density becomes so high, the gravity becomes so strong, that it’ll keep pulling everything together. There’ll be a counter pressure all the way through, like normal pressure. But gravity will win. That object in the center of a star will collapse forever. We think there’s about hundreds of millions of stellar mass black holes coming out of the super explosions that roam around our own Milky Way. Again, you have sort of hundreds of billions of galaxies, throughout the entire universe. But then in the very center of each galaxy, where you have the highest density of stars, where here we have one star, namely our Sun. In the very center of the Milky Way, we have millions of stars. Then there’ll be lots of smaller black holes forming and they will sink towards the center, and they will merge, and they form a big black hole. A black hole can only grow, black hole can never shrink, at least if Einstein is correct, we could talk about Hawking radiation, maybe later. But in principle, a black hole only knows one direction, and it will keep growing. The biggest one will go towards the center and it will assume, it will accrete and it will merge with many others. It will just eat the rest, so to speak, and become bigger and bigger and bigger. So in the very centers of galaxies, you have the supermassive black holes and our Milky Way, million times the mass of the Sun. Then in M87, this galaxy I just mentioned, it’s about 6 billion times the mass of the Sun.

Stump:

6 billion times the mass of our Sun. 

Falcke:

6 billion suns have fallen into that black hole. 

Stump: 

And then the issue with the black hole in our own, at the center of our galaxy is that it’s shrouded in various kinds of dust that makes the image more difficult to get. Is that correct?

Falcke:

The radio emission is a little bit corrupted as it travels through the Milky Way, through ionized plasma and so forth. Luckily, at the high frequencies that we observe them with, that effect starts to decrease substantially. So if you look at lower frequencies, you will not see the structure of this source. We hope that by going to the high frequencies that we do our measurements with, we actually can beat that effect, that it becomes smaller and smaller, but it still makes it a tough experiment to do.

Stump:

Yeah, let’s talk about that a little bit. First, M87, which direction are we looking? If we were to look at the night sky, which direction should we be looking if we actually wanted to face where M87 is? 

Falcke:

Well, the easiest is to go to a star chart, and look for the constellation of Virgo, in the Virgo cluster. That’s the closest cluster of galaxies in the universe, the closest cluster of hundreds of thousands of galaxies that are nearby to our own galaxy, and depends on of course, what time of the year you look, where you will see it.

Stump:

Well, if anybody thinks the process of snapping a picture of a black hole like this is simply getting a really big telescope and pointing it in the right direction and the black hole appears in the viewfinder, like what happened for you as a kid looking at Saturn and the moon, they’re going to be in for a surprise, right? Tell us about the telescope or rather, the system of telescopes, you had to use the image M87?

Falcke:

Well, it’s sort of easy, all you need is a telescope the size of the Earth, right? [laughs] If you have that it’s no problem. Since we don’t have that, we have to build it somehow and we have to use a trick. We don’t use a mirror that covers the entire Earth, I guess you would get in trouble with some people if you’d do that. So instead, we use only small telescopes distributed over the world, which already exist. We couple them digitally with wire computers, and we record the radio waves, essentially, hitting the radio telescope there. What a big telescope would do, the mirror would reflect the waves and then would bring it together in the focus, you have to focus every telescope where the light is bundled and brought together in one point. That focus would be way above the earth in our telescope. So what we do is we actually store the radio light on hard drives, we record the light in the computer. This focusing, the bringing together, we do in the computer. So we synthesize a world-sized telescope by combining many little telescopes, every telescope looks under a slightly different angle, brings its own perspective. By bringing these different perspectives together from the entire world, we can actually measure the structure and make an actual image.

[musical interlude]

BioLogos:

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Stump:

One of the, I think, really enlightening aspects of your book is the glimpse that it gives us into what the life of a professional astronomer is really. Like you had about 10 days set aside for the actual observation and data collection. And you could only observe for about five of those because of weather. But all of this was years and years in the making to get to that point. And it wasn’t all just science, right? There’s a lot of raising money and persuading bureaucracies and you had challenges like earthquakes and supply chain fiascos and even armed bandits one time, right? So how much of your time is actually doing the science itself?

Falcke:

Yeah, good question. It took 25 years for me from the first idea and you have to do it together. So half of the work is like maybe most of the work is actually convincing your colleagues this is worth doing. This is realistic, that makes sense, then, you know, finding the right team to work on this, and then has to happen internationally. Astronomers are a little bit like a lone cowboy, sometimes they do their thing in little bands. Now we have to band together in a big group, which is really transcending nations and cultures. We have people from Asia, from Africa, from Latin America, from Europe, from Africa, all this collaboration, they have to work together. So the diplomatic political buttons are sometimes as large as the technical ones. That makes science sometimes also, so fascinating of course. It’s not just sitting in your office and having a pen and paper and thinking about things. I mean, some theorists still do this. But really, this is the entire spectrum from understanding of technology, to understanding the algorithms, from developing some of those managing a team, diplomatic negotiations, finding the funding, going into competitions, to get the funding. We got a huge funding from the European Union that had a chance, when we put it in, of 1.5% to succeed. So, if you do this, you just go paranoid, when you prepare your proposal everything has to be perfect.

Stump:

So this is a very human endeavor and all aspects of being human.

Falcke:

I can tell you, it’s even more human than I write in the book. I didn’t write everything. 

Stump:

Okay, so you have all these telescopes now looking at the exact same spot of the sky at precisely the same time, and they’re collecting all the data 450 terabytes of data from each of these eight telescopes, then it takes nine months and a bunch of grad students and postdocs to sift out from all the static, the information you’re looking for. And that’s what ultimately then produces this image?

Falcke:

If you sum it up, briefly, yeah. Some of these hard drives were on the South Pole. Our colleagues in Chicago in Arizona, they actually had to equip the telescope in the South Pole and it takes an entire night. You can’t travel during the night from the south pole, and the night takes half a year. So that means the data takes a while to come back. And then you have to figure out all the issues. I always say telescopes are only human. Because every telescope has its own personality, its own problems, that you need to sort out to understand the data and you combine it. Then you see the very first time the combination of everything. It’s not yet an image, just a graphics on your computer. In fact it was my PhD student, Sara Issaoun, who’s now going to Harvard as a Hubble fellow, who showed me the first data that we had collected, kind of preliminary calibrated. It was just a curve, it wasn’t an image. But you could see, boy, that looks really interesting. That’s something. It looks like a dream result. And that’s why… 

Stump: 

What do you mean by that? What was your reaction to seeing the graph data that was so remarkable?

Falcke:

You have to do a mathematical transformation in your head. But you’re trained to do this as a radio astronomer, and it looked like a ring. When we usually observe black holes, we see this plasma streak. This is a line, so to speak, something shooting out. Like a smoke trail, this is what we usually see. We usually never see a ring, we never see a ring when we look at black holes. But this time we saw a ring. That was exactly what we expected, if we would look really at a black hole, if you get close to a black hole light would be going around in a circle around the black hole and in the center, you would not see a bright object, you would see darkness, you would see the darkness of the event horizon. And even though it was an image in my mind, an image was forming, and it looked very, very promising. We may be looking at something that nobody’s ever seen before, we’re looking at a world nobody had ever approached, we are the first to set eyes on the most bizarre point in space and time in our universe.

Stump:

What do you learn from the photograph that you didn’t know on strictly mathematical grounds?

Falcke:

Mathematically it confirms what the maths was predicting. But of course we never know what the math is and what reality is. It’s the physicist’s job to figure out which ones of these mathematical predictions represent a real world and which ones are just fantasy, so to speak. Are just abstract, they’re just mathematics. So for the first time, we really see that supermassive black holes really behave as black holes, they can bend light to go in circles, you see the darkness of the event horizon. So for all practical purposes, we can say supermassive black holes really exist as predicted. You also learn how the stuff around it is behaving. This is bizarre astrophysics, gaskets, hundreds of billion degrees hot, they’re strong magnetic fields, some of them can even launch these plasma jets and and shoot them out again. So, not all the matter that falls into a black hole or falls towards a black hole will end up in the black hole a few percent a lucky few percent are able to escape with those magnetic field lines. So if I give a talk, I tell people, if it’s one thing you learn today is if you fall into a black hole, make sure you know to hold on to a magnetic field line that gives you a chance to escape. It’s only a 3% chance, but better than nothing.

Stump:

So I don’t want to denigrate pure knowledge for the sake of knowing and the pleasure that that brings. But is there any sort of application to the knowledge that you’ve gained about black holes? Or this one in particular, 55 million light years away. Why is it important that we learn how these things behave and what they are and how they operate?

Falcke:

My first answer is because you’re curious, because we want to know what’s happening at the, at the limits of our knowledge. We want to see where we can’t go any further. And we’ve reached those points. Now we’ve looked at the beginning of the universe, we were looking towards the Big Bang, we know there’s a wheel that’s covering the beginning. We get further and then we see the darkness of the enterprise that we know, up till here, and what’s happening behind we cannot measure. So we’ve gone as far as you can go with nobody has gone before and what nobody else will be able to come back from. In the future, of course, what we want to learn is eventually quantum physics and gravity, whether there’s a theory that describes them. For the first time in the history of humankind, we have experiments that can measure in the region where it is happening. We have this gravitational waves measurement now, where we see we actually listen to black holes, so to speak, how they merge and form. And we can see black holes with Event Horizon telescopes and see how they look. So hopefully, this gives us a new theory of space and time and matter. What that will give you in terms of stock market where you should invest, which company maybe will take 100 years or more. But I give you the example of GPS that we’re using today. GPS only works because general relativity is understood and because the earth actually makes time go slower, here on the surface compared to a satellite in space. So we have to correct for that, based on the theory of relativity. And without Albert Einstein’s theory, GPS wouldn’t work and wouldn’t be understood. Why did that come about? Because people were curious, there was no technological, you know, reason to develop general relativity in 1915, it was able to explain a very subtle effect in the orbit of Mercury around the sun. Yeah, something nobody cared about, except for a few astronomers. And it was a really tiny little deviation from the theory, that was it. But this was enough to really change entirely the way we think about space and time in our universe. And it made your car navigation possible in the end.

Stump: 

So you released the image of this black hole, and it really created quite a stir. I read something like the billions of people that saw this and were amazed and had a sort of awe inspiring reaction to it. Why is it that you think an image of a black hole can evoke this or maybe even cosmology, astrophysics in general seems to evoke a sense of awe and wonder and even provoke ultimate questions about the meaning of life.

Falcke:

Yeah, the heavens declare the glory of God. I think people intuitively understand if you look at the sky and the stars, you understand there’s something bigger and deeper out there, and something that you will not be able to control or understand fully. And that’s what black holes tell us as well. I mean, there’s something that we cannot, at this point, at least understand. And they are, I mean, almost modern, mythological objects, because they speak of the beyond, they speak of destruction, they speak of death. And that’s what people think intuitively, even if they’re not scientists they feel this. From that perspective, they are fascinated by it. I call them the dinosaurs, all the kids are fascinated by dinosaurs, right? And in astrophysics, the black holes are so to speak the dinosaurs, everybody’s fascinated, fascinated by them. Just because of what they are, not necessarily because of the science. But here, both come together, this intuitive feeling and the fundamental science that we still have to learn at their edge.

Stump:

Well, in the last chapter of your book, you bring up religion more specifically, and I might get you to comment on a couple of these aspects just in closing part of our conversation. I really like how you explain there that science can’t answer all the most important questions we humans have. For example, science became so successful by adopting the language of mathematics, but there are lots of things that don’t really admit a mathematical treatment. So you say the language of mathematics gives me no insight into questions like whether I am loved or what I am worth. I think this really adds an element of humility to our search for knowledge. But then you go on to say a couple of interesting maybe even provocative things that I’d like to get your thoughts on. The first of these you say I don’t think that a completely godless physics is possible. Not if you’re truly asking questions that go right to the limits of human knowledge and then continue beyond these limits. And then you go on to address what’s sometimes called a god of the gaps problem according to which people sometimes claim that God was merely used to fill in the gaps in our understanding that we no longer have need for that. On the contrary, you say, “I say that today God is more necessary than ever, the gap of unknowing that God is meant to fill has become larger and more fundamental than it ever was.” What do you mean by those claims?

Falcke:

We have used the entire arsenal of science, of technology to go really to the extremes of the cosmos, trying to understand everything, trying to predict everything. And we are extremely successful. Let there be no question about it. Science works, science is important. And I believe that actually, as a Christian, I believe that also God speaks through science, so you have to listen to science. But the ultimate question, the hope that you really can explain every question and the most fundamental question where does everything come from? Why is it that it works? That ultimate question has become just even more mysterious, more wonderful, so to speak. You suddenly start with a few natural laws, and if some quantum cause, some [inaudible], I don’t know what the English word that’s sort of the ancient sort of sea, the ocean of nothingness that existed before the world was created. The ancient chaos, so to speak. Then with a few natural laws, and I say in the book also. To me, the laws of nature are also a word of God. Right? If you look at Genesis, God spoke, that’s the first thing that happened. And then out of this an entire universe emerges where life is possible, and everything this is miraculous. It’s natural, we can describe how it works, but the sheer fact that it works is totally amazing. It looks like I think we’ll never be able, well, I’m pretty confident we’ll never be able to explain why this works. Because people say okay, maybe there are multiple universes, we just happen to live in the one universe that works. But then where do these multiple universes come from? The question just becomes bigger in a sense. We can picture Somalia, in crafting every little detail of the earth, as we craft things, but someone just saying a word was a few natural laws. Out of this comes such a complex, wonderful Earth, with life and thoughts and songs and stories, and everything emerges from just a few words, the basic equations of this universe, we can write down on a few pages. And that’s all we need. This is just mind boggling to think about.

Stump: 

Astrophysics is often fertile ground for theistic arguments, fine tuning that you refer to there, the incredible narrowness of many of these parameters within which life can even exist, the Big Bang itself, often referred to as an uncaused cause, at least in the language of Thomas Aquinas. You mentioned at the time of the discovery of an acceptance of Big Bang that the scientific community wasn’t exactly thrilled about this, thinking that’s the phrase you use, thinking that it lets the Creator jump right back out of the coffin. Has there been any widespread return to theism among professional astrophysicists as a result of these discoveries?

Falcke:  

No, I don’t think that that has caused it because I don’t believe that you can prove God through logical reasoning. You can show that God is a very sensible assumption, a very sensible thing to live with, but I don’t believe you can prove God through science or logic. Because you can always make another argument. And that’s you always have to believe something. You don’t have to believe God doesn’t exist or God exists. You can say this fine tuning, which is miraculous, the fact that it works is just wonderful, we could always say, it’s just coincidence, it just happened to be. That’s how we can look at the world. You can say just everything that happens to me, it’s just coincidence, it just happens to me. Someone loves me, oh, it just happens, it’s just coincidence. I can say there’s a purpose, this world has a purpose. It is because there is a God that wanted that world to be there, I’m here because I’m loved, I have a place here, and God wants me to be here. Or you could say I’m just totally random coincidence, I’m just lucky. That is a pure choice, that is faith. It’s nothing you can prove scientifically. But on the other hand, let me just tell one more story. I was in Louvain, this is a Belgian University City. And that’s where the Big Bang was actually discovered, by a priest, a Catholic priest, George Lemaitre, he was very well educated. He was at all the places he was in Princeton, he was traveling through the US, at Caltech, he was talking with Albert Einstein, with all the leading physicists of his days. He was the first to realize that the equations of Albert Einstein have another solution, namely, an expanding universe as well. Einstein was worried about the collapse, but he was thinking exactly the opposite, it could be expanding. He had known about the galaxies that were measured at the time, and with just a very new result that they were expanding. So he came up with this idea that the universe could have had a beginning. I just saw like, a few weeks ago, this first graph he made of the expanding universe, he was the only person at the day that knew this. He wrote down t equals zero at the bottom of the graph. Time had a beginning, that was the beginning. And literally, Einstein and others were just saying this is repugnant, literally, they said that. You’re just saying this, because you want to defend your Catholic faith, or your faith in general. That makes me, by the way, even more angry that Christians today fight the Big Bang even though it is… As one colleague said, science of the 20th century has proven the first three words of the Bible to be correct. In the beginning, it was a beginning, you have to remember what a radical thought that was. But then, in a little article that he wrote to Nature Lemaitre said, it actually, that was the final paragraph when he was defending on physical grounds, The Big Bang Theory, which wasn’t called Big Bang at the time. He wrote a theological thinking, and he crossed it out, he didn’t send it to the journal in the end, but it’s in the original manuscript. He said, I don’t know it literally, but what a relief it is to us believers, those of us who believe that there is a supreme being, that the Supreme Being is shielded, that physics doesn’t reach that point, you cannot use physics to describe God. Physics ends at this point, t equals zero, so to speak. God is beyond that; God is beyond physics. So you have to imagine the time you were living in you were afraid that physics would describe the beginning and the end, everything was determined. And you could just calculate God, so to speak, God was a watchmaker who had nothing to do with his world. Physics told you then, that’s not true. There is a veil of secrecy, of darkness, of you not getting any further, the secret of God remains. You cannot uncover God with physics or math or logic or whatever. 

Stump:

I think it’s pretty exciting to think about the fact that physics has explained so much that perhaps we never thought was possible but at the same time has shown that there will probably always be areas that physics will never be able to explain that there is something beyond that. And our time is up here but I thank you so much for talking to us. This achievement is pretty remarkable for your career. Anything else on the horizon that’s next that may compete with it? What are you looking to do next?

Falcke:

You’re never satisfied are you? [laughs] We’ve been looking at one black hole we’re looking at more, we’re still looking at the center of the Milky Way. It’s still very exciting. Confirmation and even better tests of general relativity. We want to understand how the astrophysics works around black holes, what’s happening there. We want to understand how gravity and quantum physics go together. I think we’re just beginning in a way.

Stump:

Hmm. Well, very good. The book, again, is called Light in the Darkness, Black Holes, The Universe and Us. I recommend it. And I hope that you might write another one, we might talk again someday about what it is that you discover next.

Falcke:

Yes. I already have some ideas. 

Stump:

Good. Well, thanks so much, Heino Falcke, for talking to us. 

Falcke:

Thank you for having me.

BioLogos:

Language of God is produced by BioLogos. It has been funded in part by the John Templeton Foundation, the Fetzer Institute and by individual donors who contribute to BioLogos. Language of God is produced and mixed by Colin Hoogerwerf. That’s me. Nate Mulder is our Assistant Producer and our theme song is by Breakmaster Cylinder. 

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