Planetary Radio: Space Exploration, Astronomy and Science - Interview with Freeman Dyson

Episode Date: December 16, 2002

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This is Planetary Radio. the Planetary Society. This week on Planetary Radio, a conversation among friends about such inconsequential topics as travel to the stars and life in the universe. Bruce Betts will also be here with another installment of What's Up? and even provide a bit of advice about amateur astronomy on a very tight budget. We'll get started right after this. Very tight budget. We'll get started right after this. Hi, I'm Emily Lakdawalla, Science and Technology Coordinator for the Planetary Society with Random Space Facts.

Most people now believe that an asteroid colliding with the Earth near what is now the Yucatan Peninsula helped cause the mass extinction that ended the dinosaurs' rule over the Earth 65 million years ago. But this is not the only impact in Earth's history. So far, about 165 impact structures have been discovered on Earth, from the tiny 15-meter Haviland crater in a field in Kiowa County, Kansas, to the enormous 300-kilometer Vreed Fort impact structure in South Africa. Photos of the Earth's moon reveal thousands of craters, so why aren't there thousands of craters visible on theos of the Earth's moon reveal thousands of craters. So why aren't there thousands of craters visible on the surface of the Earth? I'll tell you the answer to that question when I return in a few minutes. Now, back to Planetary Radio.

Last September, three old friends got together for a long, speculative conversation about subjects each has taken very seriously for decades. Not that the conversation was all that serious. Bruce Murray headed the Jet Propulsion Laboratory and now serves as chair of the Planetary Society's Board of Directors. Lou Friedman once worked for Bruce at JPL and has been executive director of the Society for more than two decades. And then there's renowned physicist Freeman Dyson, the author of Disturbing the Universe

and Infinite in All Directions, was in town for a conference at JPL when he stopped by the Society's Pasadena headquarters for a chat. What you'll hear in the next few minutes are excerpts from that conversation, beginning with Drs. Murray and Friedman asking for Dr. Dyson's take on the Society's Cosmos One project, which is expected to launch the world's

first solar sail in 2003. I think it's great that somebody finally started on this. The main thing is not to raise expectations too high that this is a very preliminary counter. It's certainly

important to do it. It's important to get your feet wet and find out what the problems are. You're certainly doing that. Yes, my feet are wet. And the problem problems trying to do it for a tenth to a

hundredth of what a space agency would do it for are significant.

I always like to tell the story of Bob Dickey and the corner cube tray that

the astronaut took to the moon. Bob Dickey proposed this to NASA and when the Apollo missions began and

NASA said that's fine and so Bob Dickey gave them a cost estimate based on manufacturing and assembling this corner cube tray in the Princeton physics department shop. And the total cost was $5,000.

And then NASA said, oh, yes, that's fine, but we don't do our accounting that way. It's not flight qualified. Right. So when they did it, it was $ 3 million instead of 5,000 there is something about the first flight which we're trying to do in the Cosmos 1 mission

having to answer the question why are we doing it though just because it's never been done or what's the vision and the vision has been this fact that this is the technology, as we started discussing, that does allow us to think about the stars and the idea of traveling.

But it's also a technology that allows us to think about traveling back and forth through the solar system. Oh, very much so. In fact, that to me is much the most interesting part of it. It could become very cheap. That's the most interesting part of it. It could become very cheap if these sails are produced in large quantity and then it's essentially open to everybody. You may park them in high Earth orbit, for example.

Then you have your little sailboat and you can go wherever you want. Just like sailing ships often had to anchor out away from the coast, and smaller boats went back and forth to load and unload them, and it's the same deal. What's your biggest technological uncertainty about sailing?

In the practical, decadal time scales for use in the solar system? I would say it's all a matter of operations. I mean, the physics is easy. Well, maybe you have to get NASA out of the way first. We're doing a little of that.

Well, that's our strategy. If we can demonstrate a solar sail, even a primitive one, especially on a Russian nuclear submarine launch, that's great. They'll be shamed into it. And Europe and the Europeans are already beginning to look very seriously at this. And that's our job is to induce them to change, just like it was with Mars rovers. We got NASA seriously interested in it by demonstrating what you could do with it. Right.

Yes, so I would say that it's got to come from outside NASA anyway, but certainly it will happen one day, and it's taken much longer than I expected. The Dyson sphere is just one of Freeman Dyson's many brilliant and audacious concepts. Take a planet or two, flatten them like a pancake, and roll this thin layer into a sphere with a star in the center. You capture all the star's energy, and you have enough living space for a trillion or more people. We wondered if Dr. Dyson knew that his sphere had come to life in a Star Trek episode some years ago. No, they didn't.

In fact, I only learned about that afterwards. Well, you should feel honored. Of course. It had migrated into popular culture. To that extent, it could come back out. No, I was delighted. One of my daughters sent me a copy of the program, in fact. My daughter sent me a copy of the program, in fact.

Dr. Dyson has often speculated on both extraterrestrial life and how humans will adapt to life in space. Does he think microgravity will be the major physiological challenge some believe it will be? Yeah, I don't know whether that's important or not. I mean, nobody really knows much about that. But what certainly is true is that if people are going to enjoy being loose in the universe, they'd better be adapted to it. And it's not, I don't think microgravity is the problem. The problem is living in a vacuum.

That's the basic problem. And being adapted to heat and cold. If you lived on Pluto, it would be nice to have a good thick fur. Right. And to me, it's a much bigger question than microgravity. Everything I've seen leads me to believe the microgravity problems are quite exaggerated. On the other hand, the radiation problems are real. It's quite likely we can deal with them. Yeah, they'll be made into a showstopper for human missions.

There are many species of animal which are a lot more radiation resistant than we are. But they're not the ones we're planning to send. No. But there's no shortage of volunteers who will expose themselves to their radiation. We can borrow a few genes from the cockroaches.

Or the bugs that live in the pool cooling tower. No, I mean, certainly I think biological engineering is absolutely essential if you're really to enjoy going places. And so to me, that's really on the critical path.

I guess that comes back to the somewhat discouraged about the idea of interstellar flight being hundreds of years in the future, and you saying, well, that's really a short time. But so much happens. I mean, what will happen in genetic engineering and human evolution? What will happen in robotics technology? To me, that is fairly unimaginable. And so to try and superimpose that kind of stuff on the unimaginable parts,

on the imaginable evolution of a solar sail vehicle, is where I lose it. Yes. And whereas if it was only 100 years, I feel a little better about grabbing onto it. Yes. Well, of course, in the next 100 years, no doubt humans will remain more or less as we are, but that will change. When we return, Drs. Dyson, Friedman, and Murray will talk about how to reach the stars, including an alternative to laser-propelled sails that amounts to an interstellar pellet gun.

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The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. We continue our excerpts from a September conversation at the Planetary Society, which included brilliant physicist Freeman Dyson, chair of the Society's board, Bruce Murray, and executive director, Lou Friedman. If you were with us before the break, you heard Dr. Dyson applaud

the Society's solar sail experiment. Dr. Murray remembered a discussion he sponsored more than 20 years ago at JPL. And the question was, how do we go eventually to another star? And there was quite a

litany of people that had already contributed, including Freeman Dyson, Bob Forward, Willie Fowler, Bob Layton from Caltech, Bob Boussard. I'm probably leaving a few out. But it was just around a table, just talking, and the chalkboard, so it was a lot of fun. And so at that point, the eddy matter, all kinds of bizarre things were discussed,

and most of them didn't make the cut. And the only potentially doable system, it seemed to me, before I got dragged off to the realities of running JPL again, realities of running JPL again, was some kind of giant sail, huge sail, powered by enormously powerful lasers located in the solar system but not on the Earth, seemed to be within the bounds of physical plausibility, whereas the rest of the things didn't even seem to meet that. And so that was pretty exciting. I think at that point, I'd like to ask Freeman is that still a conclusion

with all that's happened in the last 20 years do you think there's any solution to interstellar flight involving matter carrying your fuel along or is that still probably the same conclusion no I think that's still true, but of course there's another way of doing it, which is called pellet stream,

which was promoted by Cliff Singer, which could be somewhat more economical, but it's harder to do. Instead of shooting at your sail with a laser beam, you shoot at it with pellets, and the problem then is how at it with pellets and the problem then is how to catch the pellets but in principle

the thing could be a lot smaller and more compact so it could in fact end up by being more economical but it hasn't really been worked out in detail but I think I would say the pellet stream is perhaps just as good a contender as the sail.

Do you want to define how this works and why the energy to get the pellets there and capture them is somehow less than the photons in the sail? No, the energy isn't any less. If you want to have a mass of the order of a ton going at half the speed of light, of course, that takes a lot of energy no matter how you do it. The question is just what is your efficiency? So the pellet stream doesn't, in fact, in the end, use all that much less energy,

but it just looks a lot neater from an engineering point of view. On the vehicle? The vehicle can be less massive so you save energy just on the mass of the vehicle right problem with the laser the laser sail is the sail itself weighs so much but you don't really want that because I I would like just to to to interject I, there's a lot of stuff between here and Alpha Centauri. And I think it's foolish to think that after you've explored the solar system, there's nothing else interesting until you get to Alpha Centauri. In fact, there's a whole lot of stuff coming by. And there's a fellow called Jack Bagley in New Zealand

who is observing meteors with radar, a thing called AMOR, A-M-O-R, which stands for Advanced Meteor Orbital Radar. And he actually sees stuff arriving here on Earth from Beta Pictoris, which I find very delightful. So we're already getting interstellar stuff here, and it's being measured and observed. So there is already interchange of material because Beta Pictoris as we know is a

star with a huge disk of dust around it and so we're getting some of the dust from Beta Pictoris and if we're getting dust which presumably is being thrown around by encounters with planets or something we don't know in the Beta Pictoris Oort cloud but

whatever it is there's no reason why large objects shouldn't be coming at the same time and probably they are so before we've reached the edge of the solar system

we'll probably see a lot of interlopers coming over comets and asteroids and meteors and stuff from Beta Pectoris

so it's wrong to think of all that space as empty there's all sorts of interesting stuff going on just to a. So it's wrong to think of all that space as empty. There's all sorts of interesting stuff going

Just to a geologist it's empty. There's lots of good victorious geology. A laser

sail mission to the Oort cloud would be fun. Yes, well, I don't

consider 500 years a long time. It's not unimaginable at all.

We'll be there before we know it. It's a very short time in the history of the species. But not a short time in the history of the civilization. No, but still. And so some other civilization will have replaced us by evolution, hopefully. evolution hopefully. Yes, well maybe. Some of them last longer than others. But to my mind the size of the thing

doesn't make it all that difficult. Economic growth takes care of that. What we have to do of course is to make ourselves at home in the solar system first. If we're at home in the solar system, and then we have the chance to grow economically by a factor of a million or a billion or so, then these numbers are no longer so frightening.

Interstellar travel then will be just like traveling on one planet is today. From pellet guns to space wormholes is a big conceptual leap. Dr. Dyson understands the attractive shortcuts offered by esoteric and unproven physics, but... No, that certainly could change things totally. In fact, I don't think wormholes have improved at all in the last 30 years. I mean, as far as we know, there's absolutely no way that that could actually function. I mean, all the models that we've imagined of wormholes don't allow you to travel through. of wormholes don't allow you to travel through. There are all sorts of impossibilities you have to deal with in order to get from one end to the other.

Even a robot, no, not a human. You have to have all kinds of unobtainium. What about other new physics? Yeah, what do you think of this vacuum energy and any other? We understand so much. I mean, that's one thing that we know much more about the vacuum. We know more about gravitation than almost anything else. And so it's certain that vacuum energy isn't at all difficult to understand it just is part of the background, it's certainly not a means

of getting from one place to another or a means of if not a means of getting from one place to another is it a means of getting information from one place to another faster than the speed of light? No nothing like that on the earth I would say of getting information from one place to another faster than the speed of light? No.

Nothing like that on the Earth? No, I would say one of the best features of the universe, at least as far as I'm concerned, is that the speed limit is strongly enforced. Yes. You regard the speed limit as absolutely... It's a guarantee of privacy. You just get far enough away and you're out of sight. I find that very consoling.

Keeps the sky black at night, among other things. Without that, you'll never get away from anybody. Yeah, but it's philosophically not very acceptable because it's a limit. I find it highly acceptable. Speed limits or not, Dr. Dyson still sees humankind spreading out among the stars in coming centuries. But Bruce Murray has an important question that arises from this assumption. Let me ask you another off-the-wall question. By your reasoning, maybe 500 years from now,

would this civilization descend a paleo, maybe humans, to another star? 1,000 years. Let's give it a little longer. 2,000 years. maybe humans to another star, 1,000 years. Let's give it a little longer. 2,000 years.

If that's the case, there are other, there presumably are other planets out there with other civilizations. We certainly spend a lot of our time pretending that's the case. They must have had that same opportunity. This brings us back to the Fermi paradox. Where is everyone?

Yes, that is a paradox and we don't know the answer I tend to believe that life is much more difficult to get started than most people seem to imagine of course we know nothing about the origin of life, it is still a total mystery

it's a view graph on the presentation but the simple explanation is just that life is very rare still a total mystery. It's a view graph on the presentation. Right. But, I mean, the simple explanation is just that life is very rare. And that, to me, would be quite plausible

in that this planet does seem to have been extraordinarily well-suited to life. Although life is very well-suited to the planet, in any case. Or at least evolved life

is very rare. I'm interested in the suggestion in the book Rare Earths where life may not be so hard to get started but very hard to evolve into complexity. Yeah, anyway, there are all sorts of things where you can, all sorts of ways you can

run into a dead end. To me, it's not a big surprise. We close with one last speculation about a future in which it no longer makes sense to voyage to other stars in our fragile bodies. Your thinking all along, I mean for many decades, has been about humans physically migrating out

and adapting in some form, both biologically and otherwise, to the solar system at least. There's an alternative point of view, which is that it will prove much easier for us to stay here and for only sensors and surrogates to go elsewhere, and that that'll be part of a social and cultural technical change of the human species to where we're highly interconnected, we're processing all these kinds of images in different ways, and we become more of a symbiotic organism like a coral or something like that. In that case, we don't go out.

There's not much point. Our surrogates go out, which are robotic. So that's the extreme view of the other side. I wondered again in the 30, 40 years since you first began fantasizing about some of these things, how you feel about that alternative vision. Oh, I detest it very strongly. It's quite possible. If we decide to go that way,

then I will be a rebel and I'll go off in my little spaceship and leave you behind. That's a good answer. So I hope there will be rebels when the time comes. So you won't be satisfied sitting in this room

with six walls and a hologram of data just pouring into you. No, you're virtual reality. You're there. You're there. You can move your fingers. And you're exploring. Yeah, but I've lost any freedom that I may have had.

No, it's a matter of taste, of course. But I hope there will always be people who rebel against that kind of thing. Well, it's easier to live here than elsewhere. Well, it's a matter of taste, of course, but I hope there will always be people who rebel against that kind of thing. Well, it's easier to live here than elsewhere. Well, it's dull. He's not doing this because it's easy, but because it's difficult. I think I got the answer from you. Thank you. Freeman Dyson, Lou Friedman, and Bruce Murray

let their minds run wild at the Planetary Society's headquarters last September. The January-February issue of the Planetary Report magazine will feature much more of their stimulating conversation. You can learn more on the web at planetary.org. Bruce Betts joins us for What's Up in just a minute. Stay with us. I'm Emily, back with more random space facts. The first close-up images returned from Mars in 1965 by the Mariner 4 spacecraft revealed a surface that looked disappointingly moon-like, cratered and dead with no signs of life, intelligent or otherwise. Later, Mariner 6 and 7 revealed water-carved channels,

and more recent discoveries about past water on Mars have renewed the hope that life once existed on the red planet. But no conclusive evidence has yet been found of Martians living or fossil. For more information about Mars and science and popular culture, visit the Planetary Radio page on planetary.org. Join me for more random space facts on next week's show. Here's Matt with more Planetary Radio. And we'll finish today's edition of Planetary Radio as we normally do

by visiting with Bruce Betts, the Planetary Society Director of Projects, for another edition of What's Up? Bruce, what's up? Well, this week, once again, we have some nice planets spread throughout the evening. You've got Saturn in the east early in the evening and through the mid-evening. You can see Jupiter rising earlier and earlier as the weeks go along. Now it's around 9 p.m. Jupiter will come up in the east. It'll get higher and higher, and Jupiter's the brightest object in the sky at that time. You might try, if you have even just binoculars or a

small telescope, take a look at Jupiter, and you can see some of Jupiter's large moons looking like tiny points of light, tiny stars to either side of Jupiter. And if you watch night to night, you can watch them move. You just made a really good point. And you talk about binoculars or even a small, relatively inexpensive telescope. Now, I hope my wife's not listening because I need that expensive professional scope. But really, binoculars, a good pair of binoculars are not bad for doing this kind of observing, right? That's true. They really aren't. You can pick up a lot of things with binoculars, but especially something like looking for the moons of Jupiter.

The only challenge with binoculars is just holding them still enough. You can do that, which you can do by resting your arms on something, then you should be able to easily distinguish the moons. And, again, if you look night to night, you'll see them moving because they orbit Jupiter on periods ranging from three days to 16 or 18 days. And you'll see the movement distinctly one night to the next. And what people should be looking for to see those Galilean moons are just little specks that look like stars. But as you said, if you come back the next day, they've moved.

Right. So specks and they will always they'll appear in a line because we're basically looking at the moons, their orbits edge on, and so you're always seeing a line of them. It's just they will vary where they are relative to Jupiter, and if one's in front or behind Jupiter, you won't see it. If it's not, then you will see. So, you may see anywhere from two to four moons, depending on where they are and their orbits relative to Jupiter. And by the way, Matt, you actually do need to use a really good telescope to see these. I hope Adrian's listening now. But no one else does. Bruce, what other news do you have for us? Well, we also, just to finish off, we've got Venus in the early morning sky in the southeast,

Venus the brightest object in the sky besides the sun and moon. Mars is much dimmer, just to Venus' right, very close to Venus these days. I've got some news on Mars, or at least tell you how to get some. We've had several announcements in the last couple weeks of data and new studies having to do with Mars and relating to water ice being discovered on current Mars or modeled on past Mars. Sort of intricate, so rather than go into that, I'll refer you to the Planetary Society's website, planetary.org, where you can find articles on it. You also can participate still in a couple contests we're running if you are a student.

And one is for K-12 students in the U.S., and that's to name the two Mars rovers going to Mars, getting there in 2004. Go to nametherovers.org to learn more about that or to our website. And the other is the student astronaut contest, basically high school age students who will be able to work in operations at JPL during that mission. Go to planetary.org. And how do young people qualify for that, for the second one, where they might actually end up at JPL helping to drive a rover?

a second one where they might actually end up at JPL helping to drive a rover. They will write an essay, I believe it's 1,500 words, and basically within various constraints of the real mission, they are going to propose what if they had a Mars Exploration rover and they had a couple days in the middle of the mission and they have a view which they'll be given, which is the Viking Lander 1 site, what would they do and why? Justify it. That's right. So there's always a competition for resources.

You never have enough time and power and everything else to do all you want, so you have to think about it. And then, of course, naming the rovers, which is the real thing, folks. These are the names that they're going to have when they take off for the red planet. How about this day in space history? Well, in 1968, we had the launch of Apollo 8, which was the first mission that took humans around the moon in a test leading up to the lunar landing with Apollo 11. Yeah, Apollo 8. And that was the first mission carrying human beings that actually left Earth orbit, right? Yes, it was. And it

also had other things like the first humans that got to see the backside of the moon. A lot of firsts for that mission. Kind of a big deal. Nice milestone in space history, Bruce. We assume you'll be back again with more of What's Up in next week's

Planetary Radio. I look forward to it. Thanks, Bruce. Bruce Betts, the Director of Projects for the Planetary Society. And that's it for this week's Planetary Radio. I look forward to it. Thanks, Bruce. Bruce Betts, the Director of Projects for the Planetary Society. And that's it for this week's Planetary Radio. Join us next week as we go to the set of the Starship Enterprise to talk about those kissin' cousins,

science and science fiction. Thanks very much for joining us. Planetary Radio is a production of the Planetary Society, which is solely responsible for joining us. Planetary Radio is program number 0204 and is copyrighted by the Planetary Society. All rights are reserved. Your questions and comments are always welcome. Write to planetaryradio at planetary.org.