Caleb Scharf, director of Columbia University’s Astrobiology Center talks about his latest book, The Zoomable Universe: An Epic Tour through Cosmic Scale, from Almost Everything to Almost Nothing, and the OSIRIS-REx space mission.
Steve Mirsky: Science Talk will begin after this short message.
Brian: Hey, y'all. I'm hoping you'll join me in a step back into the past, a past where you, paw, maw, gramma, grampappy, might head down to the local state fair to enter what was once called a fitter families competition.
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Andrea: And these were not about athletics; they were held in the name of eugenics. Families would happily line up to be judged on their breeding, just like livestock.
Brian: My name is Brian.
Andrea: And I'm Andrea.
Mirsky: We're from Base Pairs, the official podcast of Cold Spring Harbor Laboratory, and there's some huge new science that's making this unsettling American history an urgent issue.
Andrea: More on that later in the episode. Stay tuned.
Mirsky: Welcome to Scientific American Science Talk, posted on November 11, 2017. I'm Steve Mirsky. On this episode –
Caleb Scharf: So if you go, for example, from the scale that we associate with the size of an atom, down to the size of the atomic nucleus is at least another five orders of magnitude. And there's not much there; it's just maybe a fleeting electron, but we're made of all of that.
Mirsky: That's Caleb Scharf; he's an astronomer, and the director of Columbia University's astrobiology center. His latest book is The Zoomable Universe, an epic tour through cosmic scale, from almost everything to almost nothing. It's published by Scientific American and Farrar Straus and Giroux. He also blogs for Scientific American. We met at his Columbia University office on Broadway and 120th Street in Manhattan.
When you get a new car, it comes with this manual that most people never even look at. But this book kind of – and I don't mean this in a pejorative sense – the book is absolutely gorgeous to look at, but it reminds me of, "Here's your manual. Here's everything you need for operating your new universe."
Scharf: Wow, I hadn't thought of that way, but you're right, it does kind of have that feel to it. And, yeah, that wasn't the intent, but it's actually cool that it feels that way. I can see why, because it's systematic, but it also kind of stops off at lots of at lots of different places along the way. So it's, like, "Okay, here's the steering wheel, but did you know [laughs] that you can also do this, you know, if you push that button, or pull this?"
Mirsky: And if you're having a problem with, for example, the indicator lights, you can go right to that section. If you're having a problem with the immediate microscopic realm, you can jump right to that section of the book.
Scharf: That's right, if you're concerned about planets, you can hop in there, or if you wonder what bacteria are really up to, you can flip a few pages and you get that information. Yeah, yeah, it does kind of work like a user's manual – I like that, that's a good way to think about it: it's a user's manual for physical reality.
Mirsky: And you and also the artwork by Ron Miller is stupendous. But you cover 60 orders of magnitude, approximately –
Scharf: Sixty-three, [laughs] if we're exact about it.
Mirsky: In size.
Scharf: Yes.
Mirsky: It's hard to really appreciate what that means. I mean, you can write the numeral 1 with 63 0s following it, but that doesn't mean anything, really, to a human mind. So, can you explain what that is?
Scharf: [Laughs]
Mirsky: I mean, you do it in the book by breaking it down into different realms, but 63 orders of magnitude is such a vast stretch.
Scharf: It's way beyond what you or I ever experience in our lifetime.
Mirsky: We experience, like, six orders of magnitude, right? Maybe seven?
Scharf: Yeah, probably, I mean, if you think about the smallest thing you've seen scurrying around on the bathroom floor, to the time you looked up at the Milky Way, or maybe you visited a mountain or something. For humans, we live in a very narrow piece of the universe in terms of scale, and clearly, evolution has left us with the capacity to appreciate a little bit of it. But as we've learned about the rest of the universe, on the big scales and the small scales, yeah, 63 orders of magnitude is where we're at right now, from the edge of the knowable universe, the cosmic horizon –
Mirsky: The knowable universe –
Scharf: Yeah, the part of the universe from which light has had time to reach us, in the last 13.8 billion years, and that's kind of one measuring stick for the size of the universe right now. But then all the way down to the smaller scales – in fact, there's an equally large universe inside us. It's interesting, we kind of live close to the middle of that range, if you look at those 63 orders of magnitude, you say, "Well, what's 30 orders of magnitude in?" Well, we're pretty close to that; it's around .1 millimeters is the halfway point, in a logarithmic scale. But, yeah, for us to conceive of all these different scales is extremely difficult, and part of the deal with the book is to try to hep you a little bit. I wish I could say, "It'll make you appreciate all 63 orders of magnitude," [laughs] and it can't really do that. But I think when you immerse yourself in the book, and you turn the page, and you turn the page, and you turn the page, you begin to get a sense of just how many scales there are, and how much stuff is going on in all these different scales.
And that's another piece of the book, is trying to tie it together so that you can see, "Okay, I _____ at these scales, and these scales are imbedded in something even bigger," right, they're imbedded in a galaxy, and the galaxy's imbedded in the universe. But then, within me are things also imbedded, and so on. So, scale is a neat way of hooking you into this user manual, this tour through what's happening in physical reality.
Mirsky: And I got the impression that the book is really your way of trying to share your awe about everything that's out there.
Scharf: Yeah –
Mirsky: Because there are more – you've written other books that concentrate on one particular subject, but this is more like your appreciation for the universe.
Scharf: Yeah, it is. And I don't think it started out quite that way, but as I was working on it, and working with Ron who's an amazing artist and really has these wonderfully intuitive ideas about how to show stuff, and also the people who did the infographics in the book had wonderfully intuitive ideas, yeah, for me it became more and more personal and an opportunity – it's like the greatest pub talk, right? You're sitting there with a couple [laughs] of beers, and you start talking about what you do, and in that kind of environment, you can get enthusiastic and remember the things that got you into it in the first place. And it is that sense of awe, and part of the book is trying to capture that – for myself and hopefully for the readers, as well. And I think in places it succeeds, and I think everyone will have a slightly different experience going through it. But, yeah, that awe – I mean, awe is an interesting sensation [laughs], right? And these days, we can go through 24 hours and not experience awe.
Mirsky: Although, we will hear the word "awesome" probably once every couple hours.
Scharf: I would say so, if not more, definitely, and so, it loses a little bit of its punch when everything is "awesome." But the universe is awesome, it really is, and it's also extraordinary that we're here and capable of studying it – that's really awe.
Mirsky: You have the Einstein quote, "Perhaps the most amazing thing about the universe – "?
Scharf: Yeah, I snuck that in, and then kind of modified it a little bit. So, this is kind of paraphrasing what Einstein said, but he said, "The most extraordinary thing about the universe, or the most incomprehensible thing about the universe, is that it's comprehensible." [Laughs]
Mirsky: As far as we know, anyway.
Scharf: As far as we know. And actually, in the book, I was cheeky enough to kind of modify that and extend that and say, the most incomprehensible thing about the universe is that it is comprehensible by itself, because it has produced us, or we have emerged out of it. And 13 billion years ago, we were just uniform muck, right, just hydrogen and helium. Somehow, out of all that, these structures have formed that have minds, have the ability to look around and say, "Okay, this is what's going on." So it's kind of, it's the ultimate bootstrap, right? It's the ultimate self-starting motor, right? The universe at some point generates these things that go, "Hey, we're in a universe." That's awesome. [Laughs]
Mirsky: I keep thinking of the immortal words of Tom Hulce in Animal House: "Can I buy some pot from you?" [Laughter]
Scharf: You know, it's funny, someone was telling me that same story, last night – they really were.
Mirsky: In reference to your book?
Scharf: In reference to the book. Yeah, it's, like, "Wow, you're telling me inside my finger is a whole universe, and inside that universe is another universe." [Laughter]
Mirsky: Yeah, because you actually have the number of different scales right within your fingertip, as an example, in the book.
Scharf: That's right. [Laughs]
Mirsky: Let's talk about what you get into on both ends of the 63 orders of magnitude, just how much nothing there is. It's really mindboggling how empty the vast enormity of space is, for the most part. And also, when you get down into the subatomic realm, all the emptiness within what we think of is solid matter and atoms and –
Scharf: Yeah, yeah, we're mostly nothing. In the book, I try to get at this in a couple of different ways, so on the big scales, you can ask a question – do a little thought experiment: What if I collected together all the stars in our galaxy, right, and lined them up, put them in a box, like a box of fruit or something. Now, I can't really do that, because physics won't let me have fun, right, gravity will take over and make a mess. But let's just imagine I could do it. So, our galaxy has maybe 100 billion to 200 billion stars in it. If I brought them all together and lined them all up, it would occupy a volume actually about the same size as our solar system. It would all fit inside the orbit of Neptune. Which, if you think about it, is an incredible amount of empty space that's just been eliminated, that's just gone away like that. So, even something like our galaxy, our Milky Way, if you ever see a nice artist's impression of it – and of course we've got those in the book – it looks pretty substantial.
But [laughs], in fact, where there's space, there's really space, a lot of space, and you take that out, and you're not left with too much. You can kind of, you know, galaxy to go, you can put it in a bag and take it with you. And then, equally, like you say, on the subatomic and atomic scale, there are all these zones of scale where, at least from our perspective at the moment and our understanding of what's going on there at the moment, there isn't much. So if you go, for example, from the scale that we associate with the size of an atom, where the electrons are floating around in the cloud of probability, to go from that scale, which is, like, 10 to the power of -10 meters, down to the size of the atomic nucleus, is at least another 5 orders of magnitude. That's a lot of – and there's not much there, it's just maybe a fleeting electron.
It's just this hollow thing. But we're made of all of that. So, equally, you can squeeze all of humanity into [laughs] a very small package. I think the example people often use is when they're actually talking about things called neutron stars, which is a state of matter where you've eliminated all the electrons, and you're squashed all the atomic nuclei together. So, a sugar cube-sized piece of that sort of material, where you've squeezed out all of that atomic space, a sugar cube-sized piece would have the mass of all humans, all 7.5 billion of us. [Laughs] If you kind of dehydrated us all in a nuclear sense, that's what you'd end up with.
Mirsky: Yeah, and the picture of the sugar cube in the book, the cube is being fed upon by ants, and now it has a whole different meaning.
Scharf: [Laughs] I've just given it a whole other meaning, yeah.
Mirsky: This is not the first book, as you very forthrightly say, that attempts to cover all these scales; there's the famous Powers of Ten and that's actually a film. Your illustrator, Ron Miller, talks, in his little author bio at the end – which I couldn't help but think about, as I'm looking at the book – about the classic sci-fi movie – what's it – is it The Disappearing Man?
Scharf: Well, I guess there's the Fantastic Voyage, which is where they shrink people, and then, yeah, the Incredible Shrinking Man.
Mirsky: The Incredible Shrinking Man, that's it, where the guy just shrinks away and gets smaller and smaller. But you pay homage, in fact, to all these other efforts before you, and this one, I think, differs from those, in that those were – they're all really good, but they're pretty straightforward in terms of what they're – they're just trying to get those notions of size across. Whereas, you're also sharing our current state of knowledge about a lot of these things, and just, again, that feeling of awe.
Scharf: Yeah, I think that's right, those books – Powers of Ten, Cosmic Zoom, which was a little movie I think the Canadian Film Board did back in the '60s or '70s – yeah, they're wonderful. So we're not trying to outdo those classics; we're really trying to add to the library that they form, this library of knowledge and this idea of stepping through scales, by updating everything. A lot has been learned in the last 20 years. And we also try to do it a little bit differently, because those earlier works really relied heavily on that feeling of you flip the page, and each page is literally another factor of ten in scale. So they're really mimicking what happens when you zoom a lens or something like that. We do that to some extent, but we felt that it would be too cheeky just to reproduce that precisely. And these days, we're used to apps, and iPads, and VR, and so on, so we're a little less impressed with that kind of visceral experience.
But the beauty of modifying that a little bit, and basically adding waypoints, having stopping-off points in that journey, is it's like traveling down a highway and actually getting to stop, occasionally, and look at stuff. It's, like, "Oh, there's a sign for the best apple pie in America. [Laughs] We'll stop and look at that." Well, there's a sign for the most interesting molecule in the universe. We'll stop and look at that. Or the most interesting atom, which happens to be carbon, so we'll take a sidestep into that. So, yeah, it was an interesting process putting the book together, bearing in mind what had come before, all these wonderful works that helped inspire it. But then also, wanting to look to the future, and wanting to lay out, really, the state of the art scientific knowledge now, but also to kind of lay bread crumbs for people to see, you know, what we don't know, where are the gaps, what's coming next.
And we don't go overboard on that, but that's kind of underlying the whole book. And at the end, I talk a little bit about that, you know, what's next? Well, maybe someone looking at this book is the person who's gonna do the "what next?"
Mirsky: The idea that carbon is the most interesting atom, is that from a life-centric point of view, or is it the most interesting if there's no life, too?
Scharf: Yeah, I mean, I'm very biased. [Laughs]
Mirsky: As a living organism?
Scharf: As a living organism, you know, I need that carbon. Well, carbon is fascinating because it does have just the right set of properties, in terms of its electron count and their energy levels, to be able to form all these marvelous molecular bonds. It can bond to other stuff, and it can build big complex molecules. And it really is the only element, right now, that we know of, that does that so efficiently. There are other elements that kind of get close to it, but it's just got the right stuff – that's just how it is. And it's also interesting because of how it's produced in the universe. A lot of it is produced in a type of nuclear reaction called a triple-alpha reaction, deep inside stars, that is very finely tuned. You know, that word has a lot of baggage to it, but it's – that reaction that produces carbon is a little bit unexpected. It took people quite a while to figure out how carbon was produced in stars, because it doesn't appear to be so easy, until you spot, you know, the nuclear physics trick that lets it happen. So, carbon is interesting on many, many levels. But, yeah, carbon prejudice is big amongst living things [laughs], and I suspect that's true across the universe.
Mirsky: Right, because – it's a reductionist viewpoint, but that's –
Scharf: It's how it is.
Mirsky: That's the easiest thing to happen – in terms of building something that's alive, it's probably what's gonna happen.
Scharf: Yeah.
Mirsky: I couldn't help but think about an experience I had, years ago, where I was at a party and I heard some people talking about, there was a guy who had a TV show where he would tell audience members that he was communicating with their dead relatives. And they're talking about this, and it appears that they're really buying this. So I said, "You know that every single atom in your body was produced in a star that exploded billions of years ago?" And they said – they weren't science people – they said, "Really?" I said, "Yeah," and I said, "Isn't that just, like, unbelievable enough that you still wanna talk to dead people?" Which is clearly just, you know, this guy is a charlatan, but – "You still wanna talk to dead people?" And they both said, "Yeah, that's what we want." [Laughter] So, there's only a certain amount of enthusiasm that it may be possible to generate in people, with the kind of information that you're giving. But for those of us who are going to accept it and be awestruck by it, it's pretty incredible.
Scharf: [Laughs] Yeah, that's a great story. And I think, you know, my hope is maybe we can catch a few of those people, right? Maybe if their guard is down and they're not thinking about the after-life for a minute, and they open the book, something will catch their eye, one of the pictures, right? The beauty of an illustrated book is it can catch you without you having to read anything _____, "Oh, what's that?" So, you know, maybe that's a service to humanity, if we can [laughs] catch a few more of those people.
Mirsky: Yeah, and again, the illustrations – you know, I prefer to read on a Kindle, actually, but in this case, you want the book. Because it's a very high-production value book, with creamy thick paper, and the artwork is just beautiful and really conveys a lot of the concepts that you're talking about in the text.
Scharf: Yeah, yeah, we definitely took a lot of care over that. It's full-color all the way through, which was kind of fun, 'cause usually with books you're told, "Oh, you can't really have color – that's too expensive." So, we really went for it with the book, and I think, yeah, there's something about the physical book, you can flip back and forth between the pages. I mean, you already mentioned this, you might see an image here, you might suddenly flip over from galaxies to planets to bacteria – you can do that very efficiently. And I think visual memory is such that we piece things together, we remember where certain pages were. That happens with a physical book much better than with a Kindle or something like that. So I think, yeah, the physical book is the thing to get.
Mirsky: We'll be right back after this.
Andrea: Hi, Brian and Andrea, here, from Base Pairs, the podcast of Cold Spring Harbor Laboratory. And those fitter families competitions we were talking about at the top of the show, they were part of a dark time in America became enamored with the pseudoscience of eugenics.
Brian: Now, with new gene editing tools like Crisper being used on the human genome, we risk repeating history.
Andrea: Search for "base pairs" wherever you get podcasts, to learn more.
Mirsky: Now, more with Caleb Scharf about his blogging for Scientific American.
Scharf: Yeah, so I've been writing blog at Scientific American for a few years, now – possibly five years, maybe? I think it's coming up to five years – and it's called "Life Unbounded" – "Life comma Unbounded," I should say. And that's a little bit of an in-joke, because unbounded problems in science and physics are a particular class of problem to solve, but then it's also speaking about the nature of this thing we call life. And so, the blog is about life, it's about planets, it's about astrophysics, it's the whole shebang. And, yeah, I write this regularly, I talk about material that some of it comes up in the book, but other stuff is about the latest research, my interpretation of new results. I sometimes try to wax a little philosophical about some of it, so, for example, talking about gravitational wave discoveries, and trying to reflect on that as a waypoint in human history, because I think it really is. But, you know, you have to step back and think about it for a moment, to appreciate that.
Mirsky: Yeah, it took 100 years to confirm Einstein, I mean, considering how much else we've accomplished, that's still a good amount of time. That's how difficult it was to create the technology that enabled humanity to get these LIGO results about gravitational waves.
Scharf: Yeah, absolutely. It's extraordinary technology, it makes these exquisitely precise and delicate measurements, and it's taken the brainpower of a lot of really smart people. And a lot of perseverance – they could've got it wrong.
Mirsky: And we've got a lot of stuff on LIGO and gravitational waves on our website, so check those out. In fact, your most recent blog entry is dated October 19th, and it is basically some of the material in the book, very early in the book. But before that, you have a blog piece, just from a couple weeks ago, about the OSIRIS mission, which is a really interesting concept, so I thought we might just spend a couple minutes on that.
Scharf: So, I wrote this little piece about the OSIRIS-REx mission, so that's a space mission, a science mission, that's out there. It's en route to an asteroid, and it's actually gonna sample that asteroid and try to bring back some of that material to study. But en route, the spacecraft did something interesting: it flew by the earth. It did what's called a gravity assist maneuver, so it used the earth – it's been out there for a year or two already, and it's looped back around – it used the gravity of the earth to adjust its trajectory, in order to meet up with this asteroid later on. But it did something kind of neat when it came by: it switched on its cameras and its instruments, and it studied the earth. And it studied the earth in the way that you might imagine studying an exoplanet. Let's say in the future you fly some automated mission, way in the future, past another world, or with our next generation of incredible space telescopes, we get to study possibly earthlike exoplanets in more detail. What would they look like?
Well, it turns out that we actually have limited knowledge of what we look like in those sorts of conditions and studied that way. And this OSIRIS-REx mission kind of duplicated a really beautiful experiment that took place back in the 1990s with the Galileo Mission to Jupiter. And it, too, the Galileo Mission, also flew by the earth to adjust its trajectory, and it switched everything on, and it studied the earth. And there is a beautiful classic paper in the Nature Journal, by Carl Sagan and a couple of other authors, where it's the study of a potentially habitable planet, [laughs] which just happens to be ours. And so, it's kind of a nice, you know, blindfold experiment: "Let's pretend that we don't know what this place is. Can we tell what's happening, here?" And so, that's what they did with Galileo, and now OSIRIS-REx repeated it. And I really wanted to write about that, because I think it's such a – it's a beautiful experiment. Scientifically, it's wonderful, because we don't still have a particularly good grasp on what our world would look like if you didn't know anything about it ahead of time. If you just took some snapshots, what would you think? And so, that's what it was about.
Mirsky: And now we have a baseline database for some time in the future when we're looking at other planets to see if they have certain qualities that might make us think that they're habitable – or inhabited, even.
Scharf: Yeah, that's right, every time you do this, you learn a little bit more. You learn about what kind of chemicals you can register _____a planet – 'cause planets are a complex mix of all sorts of chemicals, but there are certain molecules and compounds that we associate with life. So you can look for that, you can look at the atmospheric composition, but you can also look at things like, "Is the ocean sparking? Does it have an ocean?" that shows up in this kind of data. So it also provides clues as to surprising things that you might go and look for, like ocean sparkle. Who would've thought, right, that you could [laughs] possibly spot that, but you can, not just around the earth, but potentially on other planets.
Mirsky: I'll be back in a moment.
Brian: Hey, all, Brian, here, from Cold Spring Harbor Laboratory.
Andrea: And I'm Andrea. Base Pairs is the podcast about the power of genetic information, and with that power comes responsibility.
Brian: In our newest episode, we speak with experts like Jennifer Doudna, cocreator of the revolutionary gene editing tool –
Andrea: – to find out how to avoid the unscientific traps that gave rise to the American eugenics movement.
Brian: Find us on Apple Podcasts, Stitcher, SoundCloud, Google Play, and wherever else you get your podcasts.
Mirsky: That's it for this episode. Get your science news at our website www.scientificamerican.com, where you can read about the huge column of magma straining for the surface under Antarctica. Why is it there? And what does it want? And follow us on Twitter, where you will get a tweet whenever a new item hits the website. Our Twitter name is @sciam. For Scientific American Science Talk, I'm Steve Mirsky. Thanks for clicking on us.
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