TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. This summer when President Trump proposed a sixth branch of the U.S. military called the Space Force, one of first people the media turned to for reaction was our guest Neil deGrasse Tyson. In the early 2000s, Tyson served on a presidential commission on the future of the U.S. aerospace industry, where he worked with political leaders, defense contractors and high-ranking military leaders. He's also well known as an astrophysicist with the American Museum of Natural History and director of its Hayden Planetarium. He's written several books, including "Astrophysics For People In A Hurry," and he's hosted several popular TV and radio programs about the science of outer space.

Lately he's been thinking about the centuries-old relationship between scientists and the military. It's a two-way-street, he says. While generals exploit technology developed by scientists for new weapons, scientists and the rest of us benefit from technology developed for new weapon systems. Communication satellites launched and maintained by the U.S. Air Force are the foundation of the GPS system used in everything from ship navigation to pizza delivery.

Fresh Air's Dave Davies recently sat down with Tyson to talk about everything from the Space Force to the chance that a rogue asteroid may be headed towards Earth and what we can do about it. Tyson's new book with Natural History Museum Research Associate Avis Lang is called "Accessory To War: The Unspoken Alliance Between Astrophysics And The Military."

DAVE DAVIES, BYLINE: Well, Neil deGrasse Tyson, welcome back to FRESH AIR.

NEIL DEGRASSE TYSON: Thanks for having me.

DAVIES: A lot of the early parts of this book are explorations of how human civilizations have advanced in technological ways often in connection with military activities or the pursuit of empire - you know, advances in navigation through the sextant and the magnetic compass and eventually telescopes. Do you find that these periods of advances in technology correspond significantly to periods of war? Do we do this more when a nation is focused on it for its own interests?

TYSON: So it works both ways. So first, the blunt answer is yes. Any time a nation engages in war and they don't want to die or they feel threatened, innovation picks up. Innovation gets stimulated and solutions to not dying arise. This has been true ever since there's been human conflict - tribal human conflict from cave to cave. Why else do you invent the club with a narrow handle on one side and a big bulb on the other side that's easier to wield than holding it the other way or creating a stick where it's the same dimension from the front to the back? So this is innovation, and its weaponry. But you could also use it to hunt down your food, right? So yes, this - that's the case.

However, what I can tell you is we are not - we the astrophysicists are not waiting around for military advances to help us. We're just plodding along, doing our thing. And what we realize - and I try to make it clear in the book - is that we're on a street, and we walk in one direction. The military walks in the other. And there's, like, a picket fence between us. And every now and then, we look over and say, hey, that's a cool thing you guys just did; is it declassified yet?

DAVIES: (Laughter).

TYSON: It will be in a year. OK, call us when it is. I want to use that to help me understand the universe. Meanwhile, they look over from their side of the picket fence and say, hey, you've got some serious intellectual capital assigned to this problem that they've been trying to solve for years. And, of course, we publish it in peer-reviewed journals that are publicly available, so they don't have to get our permission. They can just take it, and that's what they'll do (laughter) if they need it and the judgment it's in the interest of national security.

So it's just this two - it's this street where we look over each other's fence every now and then. But they're not waiting around for us to innovate any more than we are for them, but it happens in either case. And for me, the key part of this is - for me, my field is overwhelmingly liberal antiwar - overwhelming, 90-plus percent, no doubt about it. Yet we are all curiously complicit when some technology arises from the war investment that could help our cause.

DAVIES: You want to give a simple example?

TYSON: And - if there's a dot of light high up in the atmosphere, it could be the afterburner of a missile headed our way. The light - if it's high up in the atmosphere and comes down to your detector and your telescope, that light passes through many layers of air, layers that are not all at the same temperature, layers that are not all stable. Some are, like, turbulently roiling. And by the time that bit of light makes it through, the position of the thing in the sky does not precisely correspond with where you think it is from where the light came from.

DAVIES: It jiggles, right (laughter)?

TYSON: Even if it's stationary there, OK? So if you want to shoot at it, you could be just shooting at a phantom path of light that does not correspond with the location of the actual object, and it's not fundamentally different from what happens when you put a - stick a pencil in a glass of water and right at the boundary between the water and the air, there's a bend in the pencil. It looks like it's broken there, but it's not. The light is coming from different places when it reaches you from the water than when it reaches you from the air. This is refraction that's doing that, and different pockets of air in the atmosphere that have different temperatures refract the air and have that same effect on points of light.

The military wants to hit its target and doesn't want to miss, so they invented something called adaptive optics, and it is a way of tracking what the air is doing and then compensating for it at your telescope that's doing the measuring. It completely undoes the thing that made it bend and wiggle and jiggle so that when you aim for your target, you hit it. We didn't know anything about this in astrophysics until one day at an astrophysics conference, someone who is related to that study and that - those discoveries gave a paper on it. And we said, yeah, we're taking it, OK? And it had finally become declassified.

And within days, if not hours, we were - we my colleagues were drawing up plans to retrofit current telescopes to have adaptive optics on them, and every new telescope built after that has adaptive optics as a fundamental part of its design. And in that way, the starlight we find - no, we're not shooting down the star, but what happens is you take a long exposure, and the starlight which would otherwise be in one spot starts meandering in that long exposure, and it smears out in the final result what the picture of that star looks like, and it completely dilutes the intensity and precision of the data you're collecting. When we adopted adaptive optics, it transformed modern astrophysics.

DAVIES: So I want to talk a bit about space exploration - how we have managed it, how it fits in here. You write in the book that space has been politicized and militarized from the opening moments of the race to reach it. What drove U.S. efforts to explore space early on - the '40s, '50s?

TYSON: Yeah. So the word explore is kind of misleading. It's a retrospective cleansing of what actually drove it in the first place. We all remember the stirring words of John Kennedy. We'll put a man on the moon and return him safely to Earth before the decade is out. In fact, that's chiseled in the granite at Kennedy Space Center in Florida. That's from a speech he gave to a joint session of Congress in May 1961. But if you go earlier in that speech - just a couple of paragraphs earlier, what he says is, if the events of recent weeks - he's referring to Yuri Gagarin, the Soviet cosmonaut, the first human in space. So if the events of - he wouldn't even utter his name.

If the events of recent weeks are any indication of the impact of this adventure on the minds of men everywhere, then we need to show the world the path to freedom over the path to tyranny. That's the war cry for going into space, and ultimately that's what dislodged the money necessary to accomplish it, not, oh, we're explorers, and we're Americans, and this is the next step. No, that would have been insufficient to make the investment we actually did to go into space. We were at war, and money flowed like rivers.

DAVIES: And of course, I mean, the space race really got going during the Cold War when the U.S. and Soviet Union were assembling these terrifying arsenals of nuclear weapons. What was the military's attitude toward space? Was it seen as a new theater of war? Did they want to deploy weapons in space?

TYSON: So theater of war doesn't have to mean weapons. It could just mean a place that matters when you conduct your warfare. And so what space enabled - because you can now actually fly directly over other countries 'cause you're not in their airspace, space became the ultimate high ground of reconnaissance, of intelligence gathering. And so we - it was immediately adopted for just that purpose. It had other utility as well for communication. The orbits that work for transmitting information from one continent to another, special orbits - it's called geosynchronous orbits - very high up. And the thing just is sort of parked up there, and you reflect signals to it and then back down 'cause that signal wouldn't otherwise move along the curvature of the Earth. But they - it does go in straight lines that can be reflected. So yeah, so there's a whole birth of a communications satellite industry that we still enjoy today. But yes, space was politicized. And when I say militarized, I don't mean weapons in space. I mean reconnaissance in space. And that feeds efforts on the ground when you're actually conducting military operations. So yes, it's been militarized ever since the beginning.

DAVIES: Right. We're speaking with Neil deGrasse Tyson. His new book with Avis Lang "Accessory To War: The Unspoken Alliance Between Astrophysics And The Military." We'll continue our conversation after a short break. This is FRESH AIR.

(SOUNDBITE OF LOOP 2.4.3 SONG, "ZODIAC DUST")

DAVIES: This is FRESH AIR, and we're speaking with Neil deGrasse Tyson. He is an astrophysicist with the American Museum of Natural History and Director of its Hayden Planetarium. His new book with museum research associate Avis Lang is "Accessories To War: The Unspoken Alliance Between Astrophysics And The Military."

There are a lot of fascinating details that emerge in this book, and one of them that I loved - you write about, you know, at a time when satellites offered these possibilities of reconnaissance for the military - and a big change occurred in the 1970s with the development of charge-coupled devices. I don't exactly get the science here, but my sense is that this allowed images from satellites to be converted to digital files and then transmitted electronically to Earth. How did - before that development, how did the military retrieve the images that its satellites were collecting?

TYSON: (Laughter) Yeah, it's an interesting problem, isn't it? So in some cases, they would just deorbit the satellite, make sure it had a soft enough landing so that you could go back in and get the film and then develop the film. And then you'd have the images. And of course, that would engender the time delay of deorbiting the satellite, finding the satellite, developing it. And by then, the troop movement could be - it could be too late, if that's what it is you're monitoring. Or if there's a launch of a rocket, it's too late. The rocket already hit its target.

With digital detectors, of course you can now beam the signal back down to Earth and have that received. And that signal is an image. It's not fundamentally different from a fax when you think about it. A fax is sending sort of zeros and ones and converting it into a - people might not remember what a fax is, I just realized. But...

(LAUGHTER)

TYSON: It's the same idea. It's not the same technology, but the same idea. You're sending information that can be assembled into an image that created it in the first place. And the CCDs - as an astrophysicist, we were early out of the box using CCDs because they're a hundred times more sensitive to light than photographic film, which means you can take shorter exposures and get the same integrity of data. Or you can take longer exposures and see things really, really dim that you couldn't have ever even dreamt was there. So we were early users of CCDs, and they were very expensive in the day. Later on, they got up picked up by cell phones and other sort of camcorder-type recording devices. And now there's a CCD in every smartphone in the world. That's - and it's cheap.

DAVIES: So when humans learned to launch objects into space, eventually objects with people in them, I mean, there were all kinds of possibilities this presented. And you write that the United States and other countries had to figure out what its policy was going to be with respect to the military uses of space. How did the government approach this question? Who decides it?

TYSON: Well, all right, so go back to the 1960s when the space era was 10 years old. So we're now speaking of 1967. The U.N. felt it necessary, justifiably, to come up with a peaceful use of outer space treaty. And if you read this document whose title is much longer than I just recited to you, it's committee-long, OK?

DAVIES: Right.

TYSON: They should have - they needed some marketing folks to get in there. But basically, you could think of it as the treaty for the peaceful uses of outer space. And in it, it reads like kumbaya, oh, my gosh. And we will go together and explore together and use the results to benefit mankind, and if one of your astronauts is in trouble, I will come to their assistance. And it reads beautifully, and the spacefaring nations of the day were signatures to it. And to this day, last I checked, there's 107 participants in the treaty. Oh, by the way - and it prohibits weapons in space, OK? It was very clear about that.

Now, here's the problem - a fact. It allows you to have defensive capability of your activities in space. And all right, so there's a gray area there. What do we mean by that? Well, let's say I'm a satellite, and I'm going to nestle up next to your satellite. And I have some radiative field that will scramble your data, and you don't want that to happen. But you just see me ambling over towards you. Now you whip out your lasers and destroy me. Well, I hadn't really done anything to you yet. You feared that I would hurt you, one satellite says to another. And I just took you out. Is that a first strike? Is that aggression? Is that - or is that used in a defensive way? This is still a bit of a gray area in the interpretation of that of that treaty.

DAVIES: Right. And one could also - speaking more broadly, I mean, if I'm a country that believes that I stand for democracy and freedom and I'm going to deter aggression, well, part of preserving freedom and democracy is military action in some circumstances against a mean authoritarian regime. That's you. So I can attack you, and that's defensive. It's peaceful because I'm preserving peace and democracy.

TYSON: Yeah, and that's part of that the wiggle room that exists. So it's not clear how binding the thing will ultimately be. I viewed it not so much as something that everyone will obey to the letter. I viewed it as a hopeful gesture that maybe when we all go to space, we'll all get along. That's how I really viewed it, as a - that we are capable of signing a document that we'll never fight again. Now, my - as I got older, I got more cynical. I'm seeing the world not through rose-colored glasses but through crystal-clear glasses. And I realized, who were you kidding? What do you mean when we go into space, we have to be nice to each other? What do you mean by that? I'm not nice to you down here. Why should space make any difference to that at all? And if I can be nice to you in space, why can't I be nice to you on Earth? Where's the peaceful use of Earth treaty? How about that? Why don't we start with that? And if that works, hey, now I might believe you that you can have a peaceful use of outer space.

DAVIES: In the book, you quote a Nobel laureate in physics who says the International Space Station is an orbital turkey. This person says no important science has come of it, almost no science at all, and further says that - this person would say that the whole manned space flight program, which is enormously expensive, has produced nothing of scientific value. What do you think of that point of view?

TYSON: So let me first tell you on this program what I have said to his face, OK? What I said was, we go into space as a nation not to serve scientists. You are naive to think that the entire existence of the space program was to advance the cause of scientists. That - I'm sorry, that is not how the world works. We went into space driven by geopolitical forces. Not only that, every astronaut but one that we had ever launched into space - Mercury, Gemini and Apollo - was an active or former member of the military. So to think of this as, oh, you're wasting money; it should be spent on my experiment - that's just naive.

And so the fact is when the country is exercising its geopolitical interests, science piggybacks that - to great gain, I might add. And - it's that has been that case forever. I can go back to Captain Cook's voyage, to the - Darwin's voyage on the Beagle. The Beagle didn't go to the Galapagos Islands for him. It went there - had his own agenda, and he hitched a ride, practically was a stowaway on the boat. So science happens not because governments care about science - only in a small way. Science happens because governments care about other things that need the science. And in its most visible forceful expression, it could be dominion building, empire building, hegemony - all of this.

And by the way, he's a friend. His name is Steven Weinberg. He and I went to the same high school, the Bronx High School of Science here in New York City. And so we've talked about this and other topics. He is right. Not much science has come out of this. But that's not why we did it in the first place, so therefore I cannot fault it.

GROSS: We're listening to the interview FRESH AIR's Dave Davies recorded with astrophysicist Neil deGrasse Tyson. His new book, "Accessory To War," is about the unspoken alliance between astrophysicists and the military. After our break, they'll talk about President Trump's proposal for a new branch of the military, the Space Force. Also, we'll have reviews of Wayne Shorter's new album and the new nonfiction book "The Real Lolita" about the kidnapping case that helped inspire Nabokov's novel. I'm Terry Gross, and this is FRESH AIR.

(SOUNDBITE OF ALEXANDRE DESPLAT'S "EXTREMELY LOUD AND INCREDIBLY CLOSE")

GROSS: This is FRESH AIR. I'm Terry Gross. Let's get back to the interview FRESH AIR's Dave Davies recorded with Neil deGrasse Tyson. His new book, "Accessory To War," is about the unspoken alliance between astrophysicists and the military. In the early 2000s, Tyson served on a presidential commission on the future of the U.S. aerospace industry where he worked with political leaders, defense contractors and high-ranking military leaders. He's also hosted several popular TV and radio programs about the science of outer space and has written best-selling books.

DAVIES: I'm interested in your impressions of the Trump administration's views, approach to science. They're talking about creating a new branch of the military, the Space Force. What do you think of their approach to space exploration?

TYSON: You know, just because something is uttered by Donald Trump does not require that it be a crazy idea. I just want to make that clear. Back in 2001, I was appointed to a commission by George W. Bush to study the future of the aerospace industry of the United States. It had fallen on hard times. And I was one of a 12-men-member commission. And we represented the full spectrum of political, cultural views. We had aerospace management as well as aerospace labor. We had people who were Republican members, ex-Republican members of Congress, and Democratic members. I'm an academic, so I'm fundamentally left-leaning. I'm on the panel. And so there we are.

And when I saw that we have this aerospace industry falling on hard times, I put it in the table. And I said, has anyone considered breaking the space activities away from the Air Force and creating a Space Force? And those others - there was a four-star general from the Air Force. He said, I think we got this. You know, we - there's U.S. Space Command under the umbrella of the Air Force. OK? So they felt pretty comfortable with it, and I'm not going to second-guess that. It is a four-star general who runs it. So that's fine. And then we left it on the cutting-room floor.

It is not a crazy idea. If you did it, you would remove all the space activities that are currently overseen by the Air Force into its own category called a Space Force. That would be the bulk of what the Space Force would be, stuff we're already doing. Then I would throw in a couple other things if you're going to do that. I'd throw in, hey, why don't you defend us against asteroid strikes? And how about cleaning up the space garbage? That could be defensive because you don't want space garbage interfering with our space commerce. I might add a few things to its portfolio.

But it's not a crazy idea any more than it was crazy to separate the Air Force from the Army. The entire Second World War was fought with the Army Air Force, Air Force as a branch of the Army. And it was clear that command and control in the air is different from command and control on the ground. You're soldiers or pilots. You're engineers or aerodynamicists. Today, no one would question the need and the value for a branch of the military called Air Force. And I - probably in the future, if we made an - a Space Force today, it wouldn't be questioned decades from now.

DAVIES: OK. What do you think of the Trump administration's policies towards other aspects of the study of space? I think you do mention that there were plans to fund a wide-field infrared telescope that are probably not going to happen.

TYSON: Yeah. There's a lot that goes on with regard to science under any given administration. There's the background of science research that's conducted no matter who is president. And that takes place through the funding channels of, in the biological sciences, the National Institutes of Health, the NIH. The National Science Foundation is the primary funder of science in my field, as well as NASA. And so these monies, yes, they're budgeted each year under different Congresses and different administrations. But basically, if they change, they don't change by much. So there's a fundamental level of science that's going on no matter what the rhetoric is of the Commander in Chief.

I can tell you that, historically, budgets for the science portfolio of the United States under Republican Congress has been statistically higher than it has been under Democratic Congress because at some level, holding aside denial of climate change and other things that could be the end of civilization - hold that (laughter) aside for the moment - informed and intelligent Republicans know and understand the value of innovations in science and technology to drive tomorrow's economy. So that's what accounts for this support, very broad support, for the National Science Foundation over the decades. So whatever Trump says, it can have, like, effects on the edges, yes. But in terms of the major bulk of the science portfolio of the United States, it's a ship in motion no matter who's in charge.

DAVIES: Is there technology which could find and destroy targets in space such as, you know, bodies like asteroids that could threaten the planet? Is that a realistic thing?

TYSON: No. Well, it's realistic. We just - there's no funded agency or program to actually do that right now. And this was my point about, if there is a Space Force, why don't we task them with that goal? And by the way, that would be the noblest of all goals because if you could deflect an asteroid, then you are saving not only your country, but all other countries on Earth, because a big-enough asteroid could render us all extinct as - just ask the dinosaurs (laughter) from 65 million years ago. That was a Mount Everest-sized asteroid that came in and completely altered the climate, knocking out the base of the food chain, rendering 70 percent of the world's species extinct.

So - by the way, we have ideas on how to deflect asteroids. There've been conferences, engineering conferences, on how to do it. Do you blow it to smithereens? Well, that's the macho way. Do you deflect it? That's the kinder, gentler way, and you can monitor your progress. Do you paint one side of it black so that it absorbs sunlight and re-radiates it with a differential pressure from one side of the asteroid to the other so that, under natural causes, it drifts out of harm's way? There're all these really innovative plans for how to deflect an asteroid, and there's no money to do any of it.

DAVIES: Are we safe? Is there a realistic possibility that terrible damage is out there waiting to hit us?

TYSON: Oh, yeah. For example, just a few years ago - was it 2013? - an asteroid the size of a house exploded in midair above the Russian town of Chelyabinsk. And the reason why something would explode in midair is that it's moving so fast from space that when it goes through Earth atmosphere, it's going so fast it's as though it hits a brick wall. And you could do this experiment. Go 60 miles an hour down the road, roll down your window and stick your hand out the window. You'll see how hard it is to keep your hand rigid against that wind. Your hand gets pushed backwards just by 60-mile-an-hour wind.

Now imagine you're going 10, 15, 20 miles per second, and then you hit Earth's atmosphere. You're not just gently passing through it. You - all of your kinetic energy gets stopped and pumped back into you, and the only way that can manifest by doing so is for you to explode. That happened over Chelyabinsk. It created a shock wave that shattered practically every window in the town. And people standing near the windows got laceration injuries. About a thousand people were injured.

I call it the Band-Aid incident because no one died because it was simply the shock wave and the broken glass. But had that thing been larger and was able to hit the ground and make a crater, had that thing hit a major metropolitan area rather than the lower-density areas of the Ural Mountains - oh, my gosh. So for me, this Chelyabinsk asteroid was a shot across our bow from the universe. And it said, here you go. You just pull out the Band-Aids for this one. I'm not going to kill anybody. Just don't make this mistake again. Deflect me next time. And so the problem is, something as small as a house, you only discover it when it's too late. So yeah, I'm very disappointed with civilization that we've got nothing going on this.

DAVIES: What questions are you interested in these days as an astrophysicist?

TYSON: Yeah. I have a cop-out answer.

DAVIES: (Laughter).

TYSON: So please forgive me as I give you this answer, but it's really true. All right? For me, the questions I care most about are the ones I do not yet know to ask because they will only arise after future discoveries have been made. Those questions keep me awake at night because I don't even know how to pose them.

DAVIES: You're confident they will emerge?

TYSON: Oh, of course. They emerge all the time. Look at the big questions 50 years ago, 100 years ago. They're not even - we don't even care about those questions. We're asking other questions undreamt of by those previous generations. Those are the questions I want access to, the questions we don't even know to ask, because we're not standing in the place where we see that those are questions that await our curiosity.

DAVIES: Well, Neil deGrasse Tyson, thanks so much for speaking with us again.

TYSON: Thanks for having me.

GROSS: Neil deGrasse Tyson's new book is called "Accessory To War: The Unspoken Alliance Between Astrophysics And The Military." He spoke with FRESH AIR's Dave Davies, who is also WHYY's senior reporter. After we take a short break, jazz critic Kevin Whitehead will review Wayne Shorter's new album. This is FRESH AIR.

(SOUNDBITE OF DEEP BLUE ORGAN TRIO'S "TELL ME SOMETHING GOOD") Transcript provided by NPR, Copyright NPR.

NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.