More Science Talk
Nobel Prize-winning physicist Frank Wilczek and Scientific American editor George Musser talk about the Large Hadron Collider, the most powerful particle accelerator ever built, which went online this week. Plus, we'll test your knowledge about some recent science in the news. Web sites mentioned in this episode include www.frankwilczek.com
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Steve: Welcome to Science Talk, the weekly podcast of Scientific American. They flipped the On switch for the Large Hadron Collider this week. We will talk with Nobel Prize–winning physicist Frank Wilczek about the LHC and then we will get some commentary from the Scientific American editor George Musser. Frank Wilczek is the Herman Feshbach professor of physics at M.I.T. In 2004 he won the Nobel Prize for discovering what's called asymptotic freedom in the theory of the strong force which holds subatomic particles together to make protons and neutrons in the atomic nucleus. For more on that, check out the May 3rd, 2006, edition of Science Talk. Wilczek was on the Scientific Advisory Committee of the LHC for six years. Forgive the sound of my voice on the telephone connection. I flipped a switch incorrectly and my voice is a little over modulated, but don't worry, I don't say too much.
Steve: Dr. Wilczek—thanks very much for talking to me today.
Wilczek: My pleasure.
Steve: Let's get to the most important thing for us. How is your opera career going?
Wilczek: (laughs) My opera career has moved into the realm of the ideal, I think.
Steve: You did sing opera—and where was it, Austria?—a couple of years ago.
Wilczek: Yeah, yeah; well, a light opera.
Steve: Light opera.
Wilczek: Light opera; well it was a lot of fun.
Steve: Well speaking of light, lets move on to the subject in hand. It's all over the news the last few days—the Large Hadron Collider. Let's talk to people who are just hearing about this kind of material for the first time very quickly. Give me the one minute explanation of what any kind of particle collider—what they used to call an atom smasher when I was a kid—tell us what that does.
Wilczek: Well it's an instrument for allowing us to study these most basic processes of nature as they occur at very short distances or very high energies. So that's the goal; that['s] the heliological explanation of what's going on in an accelerator. Now what you actually do is bring particles—in the case of the Large Hadron Collider protons—that is the nucleus of hydrogen atoms and you accelerate particles so that they're moving very, very rapidly, they have a very large energy in their motion; and at the Large Hadron Collider, the LHC, the protons will be accelerated to within a part in the billion of the speed of light. So very, very close to the limiting velocity. They'll be moving around, guided by magnetic fields in a gigantic circle, 26 kilometers or 17 miles round. There will be two beams that will begin [in] opposite directions and at a few points the beams will cross so that the protons moving in opposite directions can collide. In those collisions, an enormous amount of energy then will be concentrated in a very small volume and that's what allows us to access these short distances; and so that's a kind of a giant microscope to see what goes on in empty space when you look at very short distances over very short times.
Steve: And when you smash the particles together—and by the way, at these speeds how long does it take for them to make the trip around the 17 miles?
Wilczek: Oh! I don't remember actually, but it's not, it's...
Steve: He is doing the computation.
Wilczek: Yeah, I am a little slow this early in the morning.
Steve: The point being that it is a tiny fraction of a second.
Wilczek: It's a very tiny fraction of a second.
Steve: Right, right. So now when they smashed, together all kinds of things happen; you get all kinds of other particles that come off and that get created and then vaporize in an instant and then this gives us basic information about the structure of the universe.
Steve: Okay now, what is a Hadron, other than a Roman emperor?
Wilczek: Well (laughs) a hadron is a particle that is made out of quarks and gluons, a particle that participates in this strong interaction. So in the first instance, a hadron is a proton; a proton is the prototype hadron and that's the one that is in the LHC normally, but also to explore other aspects of the fundamental physics. From time to time the accelerator will accelerate other things than protons, that is a gold nuclei or iron nuclei. So we have to use a more inclusive term that hadron includes both protons and heavier atomic nuclei.
Steve: Okay, so for the most part though, the LHC will be a large proton collider.
Wilczek: That's right.
Steve: That sounds good. Now in a Scientific American article that came out earlier this year, you were quoted as saying that the LHC is going to be instrumental in bringing about, hopefully, a golden age of physics. What is so special about the LHC compared with the various other particle accelerators, atom smashers that are currently in existence around the world?
Wilczek: Well our equations have been pointing us to the belief, the expectation, that the LHC is getting to probe the distances where new basic processes of nature will be revealed. We have a very powerful, very accurate theory of normal matter which [is] usually called the Standard Model, or, I call it the Core Theory. Standard Model sounds boring, but the equations of the Standard Model are incomplete. They haven't been tested in some of their most remarkable consequences. They are based on the idea that the despite appearances, what we call space and experience as emptiness in everyday life is actually a highly structured medium that's full of stuff. It's as if [we're] fish in an ocean that affects how we move, how fast we can get around, but since we live with it, in it everyday, we think of the ocean as just the normal state of affairs; but eventually being smart fish, we realize that there's some material that's affecting the way we move and what the LHC is in this analogy is the instrument that's going to allow us to see what the atoms of water are and tell us what this medium that we're immersed and is made out of; and that's called looking for the Higgs particle. Because the simplest idea of what it is that it's a new particle that builds up this ocean we live in. But it doesn't have to be just one particle, in fact, but I think the more interesting ideas indicate that it is not just one particle but that's the medium is made out of several things and may be a whole new world of phenomena that will be revealed; we actually have enough resolution and enough discrimination to finally see what this medium we're immersed in is made out of.
Steve: Right, because you are a supersymmetry guy.
Steve: So there's going to be a lot of new particles out there for you.
Wilczek: Yeah, I think that the next idea—which is slightly more speculative, well a lot of more speculative, but I think very compelling—is that we know ways to make our current, very accurate but somewhat lopsided equations that are based on the idea that there are several fundamental forces into a new synthesis in which all the different forces appear on the same footing—what we call a Unified Field Theory. We have ideas for achieving that that really looks very compelling, I think, [and] even have some quantitative success, but the success so far is indirect. Fortunately the same ideas predict very concrete new phenomena, a whole new world of particles that have to be accessible at the LHC and so [we have this] wonderful idea that we've been entranced by for 25 years, and the kind of the thing that Einstein dreamed of, unifying the forces, and now is the time of testing [whether these] ideas have been on the right track; whether nature has, with all these hands, has been teaching us or just teasing us.
Steve: Well put. The Higgs particle or the Higgs boson gets a lot of mention in general media articles as the first thing that they are going to really hope to find at the LHC.
Steve: For people who don't know anything about it, can you just explain a little bit more about what that Higgs thing is out there?
Wilczek: Yes. Our equations are most naturally formulated in terms of particles and fields that have zero mass, but in the world, particles don't have zero mass and the way we reconcile the two is by saying that, really, the particles in themselves do have zero mass but they are moving through a medium that slows them down. This is the analogy I was talking about before with fish that are moving through an ocean: They figure out finally that something has been slowing them down. And the thing that's slowing them[—us or the particles—] down is some kind of medium; and we know some of the properties of the medium, but we only have guesses about its atomic constitution, well, you know, what it's really made out of. The simplest guess is that it's made out of a new kind of particle called the Higgs particle. So just one new kind of particle; but the other ideas of that unification that I mentioned in supersymmetry suggest that it is more complicated; that there at least are several different kinds of particles involved, you know, like hydrogen and oxygen in water where water also has impurities; though we are going to find out anyway what this medium is made out of.
Steve: So let's take just a minute. Thanks very much for talking us through these kinds of basic points about the LHC. Let's take just a minute. I know you have a new book out: The Lightness of Being.
Steve: Tell us about the book.
Wilczek: Well, it's a book that describes the riches of modern physics, of that very surprising reality that [we] live in and I hope, [in] a way, that we'll enrich people's understanding of the world they live in. So the way I weave through all this stuff is through the concept of mass. So I start by describing how we understand the origin of mass of ordinary matter, for normal matter, the stuff you and I are made out of, really starting from constituents that have zero mass, realizing Einstein's dream of reducing mass to energy explaining how mass arises from energy, which is a more basic concept. But really understanding that opens up whole new worlds of ideas and synthesis because it explains, for instance, why gravity, one of the basic forces of nature, appears to be very, very different and very, very much weaker than the other forces. Gravity responds to mass. So when you understand mass more deeply, you'll start to understand gravity more deeply. These ideas all come together with the underlying concept that what appears to us as empty space is a rich dynamical medium. And that dynamical medium kind of hides from us the underlying simplicity and unity of nature. And now that we're starting to understand what empty space really is and we can correct for the distortions that it introduces, and get this vision of an underlying unity and symmetry among all the different forces of nature, [then] we are going to find out very soon if it's correct; and if it is we'll be ecstatic and feel high that we're in a truly marvelous ideal mathematical world that I think adds to or takes our understanding of what the reality [is] to a new level.
Steve: So what do you think? More fun to be a physicist today or in 1905?
Wilczek: Well, we'll see. (laughs) I don't really want to compare one goal to another
, but if we're lucky, it'll make the world appear a very beautiful place.
Steve: Frank Wilczek's Web site is www.frankwilczek.com that's W-i-l-c-z-e-k.
Steve: Scientific American editor George Musser has been following the development of the LHC since it was a gleam in physicists' [eyes]. I spoke to George about the LHC at our offices.
George, why is this such a big deal? Why is the science community really excited about the start up of the LHC?
Musser: Well, it's for a number of reasons. First of all, this is the biggest, most expensive scientific instrument in history. This is the Apollo project of physics. It has been a long time coming; there has been a lot of disappointment along the way; you know the Superconducting Supercollider.
Steve: The one that was supposed to go in and be built in Texas.
Steve: What, 15 to 20 years ago at this point?
Musser: Yes, that's right. It was proposed, they dug a hole in the ground and two billion dollars was poured into said hole and now, know nothing there. Although a lot of the technology that was developed for that is now winding up at the CERN Lab for the LHC. So it's not a totally lost cause, but still physicists have now had to wait 15 years to probe into the next energy realm that they wanted to get to; the one that will really take them beyond the Standard Model of physics.
Steve: And let's take just a second. You know, I heard some headlines this morning. We're talking on Tuesday, the 9th. Even the venerable BBC, not to mention WCBS radio here in New York City, and both headlines were about the LHC and they both went something like this: "The LHC is ready to start up tomorrow and it's going to either reveal secrets of nature heretofor unknown or it'll destroy the world."
Musser: Well those are the only two options we've got. I guess we're good to go.
Steve: I was actually really kind of peeved at their...
Steve: I mean, I understand why they do it. They are trying to attract listeners. But it makes it sound like it's a 50–50 shot and some of the press attention to the collider is dwelling on the possibility of the creation of these mini black holes that could become, that could grow and, you know, destroy the entire planet, solar system, but so why don't we talk just from all around why that's really press sensationalism.
Musser: I think the scientific community and science journalist[s] bear a little bit of [the] responsibility for that perception among the public because we always talk about the LHC as recreating conditions not seen since the big bang, and you would therefore think if there hasn't been an energy level like that seen since the big bang, then all the phenomenon of the big bang might be unleashed upon us; these black holes, possibly being one, because people do talk about black holes having been created in the early universe.
Steve: Tiny, little black holes.
Musser: Tiny, little ones. And by the way I would like to call them is "tortured souls." If you think of your big cosmic sink holes as the monsters of the cosmos, these are all black holes or the tortured souls. They just go pop, they are harmless; they'll just evaporate almost as soon as they are made. In fact they'll evaporate so quickly that even if the collider could make them, which is already questionable, they would just [dis]appear before the instruments could [measure] their existence. All you would see will be the debris that they would just spew out. Now it's a question whether they can even be made; people debate that. There has been some talk among string theorists in particular that the collider might, in the most optimistic to them of cases, create black holes [that would] pop before they could cause any damage. The concern that people had was that they might not go pop, they might linger, they might continue to exist and start to suck things in. Even if that were true, which is probably not the case, they are so tiny that they did still have enough sucking power to them. It would take a long time, billions of years even for them to grow to an appreciable size, so that is the worst-possible-case scenario.
Steve: The worst case scenario is we actually do create the doomsday machine but it takes a few billion years before it has any effect.
Musser: Exactly, by which point, of course the Earth is already toasted by the Sun and so forth. Now the difficulty with even getting to that worst case scenario is that the very laws of physics that predict the creation of the black holes also predict the destruction. So it would seem pretty perverse for nature to allow their creation and not their destruction. That would mean the physics laws that predict them would have to be wrong and very, very specifically and even if [it] were to happen, you would have billions of years, and not to worry.
Steve: To figure it out.
Musser: You're right.
Steve: So this is just a scientific instrument, as massive, as expensive, as unique, and as groundbreaking, as it is. It's still just a scientific instrument. It's not going to destroy the planet.
Musser: Yes, that's right.
Steve: And in fact it may change the way we look at nature although. If it does, it will take a long time probably for that to, kind of, sink in to the population at large but these things do happen when we have major new scientific insights; it does change the way people think, it may take decades for that to happen, but it would [and] does happen.
Musser: Yeah, I think so. I think, I mean, of course I live and read this stuff. So [it] changes the way I think and changes the way that the scientifically interested public thinks. But I think there is a ripple effect, drop [a] stone in a pond and it ripples outward and that's also the same [with] scientific discoveries. Who would have thought that quantum mechanics, which in the 1920s was the most esoteric possible disharmony you could think of, would account for such a large percentage of our economy today—lasers, transistors, and all the like.
Steve: Well, what's the famous quote? There are only three people who understand it.
Musser: And was it Eddington?
Steve: I think it was Eddington.
Musser: And [he] said, "Who are the other two?"
Steve: Right, right.
Musser: But of course even that wasn't really true, because even in its time, the physicists and even interested members of the public really caught on to the theory and just started to grasp its implications and its deep meaning for the universe. But anyway, that seemingly esoteric field is now powering a huge fraction of our economy as well.
Steve: Relativity is?
Musser: Special relativity in particular. Special relativity is incorporated into the Standard Model of particle physics. General relativity is a little bit more out there but even things like the GPS system—global positioning satellites—rely on it for their accuracy.
Steve: Right, right. Okay.
Musser: The way I think of the propagation of scientific knowledge [is that] it is in multiple stages. So there's going to be the initial stage [where] they discover new dimensions or new particles or what have you, or just, "Wow, isn't that amazing?" So there's this kind of gee-whiz stage of it, and then you also see those ideas seeping into the theories, disproving some, suggesting that others are on the right track, proving some even; and those theories, in turn, incorporate principles, new laws of nature, new principles of nature that will, I think, inform our broader culture.
Steve: Does the large in Large Hadron Collider refer to the collider or to the hadrons?
Musser: That's (laughs) credited to the collider, to the collider.
Steve: Because the hadrons are all pretty much the same size.
Musser: Pretty much, although there is some variation because of the speed they...
Steve: Right, right.
Musser: ... and the energies they have, but they are all 10 to the minus 15 meters across, the protons.
Steve: And those, that['s a] pretty small size.
Musser: The distances, to which they were able to probe the energy that they have, the high energy corresponds to short distances; that's just the law of quantum mechanics. I think it goes to 10 to the minus 18 or 10 to the minus 19 meters. So that's the structure within the proton that they get to. So they are able to smash open the protons and new particles will form and will reform from the debris.
Steve: For a fleeting [instant].
Musser: No, some of them could be long lived.
Musser: So for instance they are trying to create, ideally, dark matter; one of the mysteries of the universe [they are] trying to solve with the Hadron Collider is, what is the dark matter? Astronomers know it's there, but physicists have no idea what it is. What particle could constitute the dark matter in the universe? So physicists hope, astronomers hope, and everyone hopes that the collider could actually create the dark matter and the dark matter is a stable particle. So it would just fly out of the accelerator and would just go into deep space.
Steve: And what would the evidence for it be?
Musser: It would be missing energy. So what they would do is, the physicists would take all the measurements they made, add it all, extrapolate back and just try to put the pieces back together and see what came out of the collision of the protons; and in some cases they might notice that there is this gap; they could only account for may be 80 percent of the energy of the collision, 20 percent no matter how hard they looked; 20 percent that was lost. And of course energy is not ever lost; it is only converted from one
from [form] to the other. So the deduction from them would be that the 20 percent or whatever percent that was taken away by a particle that escaped.
Steve: So the next few months, couple of years, [are] going to be very exciting in the world of particle physics.
Musser: Definitely; years probably. You know the thing that's happening this week; they are just starting it up.
Steve: The beam is being tested. We're not even smashing anything individually.
Musser: Not even smashing. The smashing does not occur for a couple of weeks yet and then they shut the thing down in November because of the energy cost of running it. They need to actually heat the city of Geneva as well and they need to use the energy for ordinary uses.
Steve: It takes that much energy that your options are run the collider or heat Geneva.
Steve: It's pretty amazing.
Musser: So they shut it down and pick it up again in spring; and then they'll actually ramp up to the full energy level. The first goal that they will have is simply to rediscover the particles they already know, to rediscover the Standard Model; the electrons, [the] whole gang of particles of the model.
Steve: And is that a test of the collider?
Musser: It is the test of the collider; it's the test of the theory. It also sets a benchmark of measurements, because they'll measure it to that greater precision they already have and therefore any deviations from those predictions would be more significant.
Steve: What's the next instrument on the drawing board after the LHC?
Musser: Well the next biggie is the International Linear Collider. We've had an article about that as well in February.
Steve: February 2008.
Musser: That's right, and it is a follow on instrument to the Large Hadron Collider. The Large Hadron Collider is really your pioneer setting out into the new frontier in trying to just find out what's there; and the ILC, this new one if it's built would be the, kind of, the consolidator. It would make precise measurements of all those particles that had been discovered and in a sense actually that's where lot of the big discoveries will come, is from that ILC because of the precision it can attain.
Steve: So we start with the LHC that gives us the energy levels we've never seen before, then the next instrument will give us the precision that we haven't had.
Steve: So that one hasn't even, there are plans but they haven't even worked on the ground for that.
Musser: No, no, no. But there is a consortium now of the three main countries or groups of countries—the European Union, the US and Japan—that are really footing the bill for the collider and [there] would be site in one of those three countries for the collider; and they've already kind of consolidated and kind of [pooled] their resources; so that initial step is almost the hardest—getting the three countries to agree on anything; and they've done that. So the human side is, kind of, the bureaucratic side, has kind of been taken care of; now it is a question of getting the money and meeting the technical challenges.
Steve: So we are going to have lots of new particle physics fun to talk about for many years to come.
Musser: Oh yeah, my job is safe.
(Twenty-seven kilometers of tunnel underground
Designed with mind to send protons around
A circle that crosses through Switzerland and France
Sixty nations contribute to scientific advance
Two beams of protons swing round, through the ring they ride
'Til in the hearts of the detectors, they're made to collide
And all that energy packed in such a tiny bit of room
Becomes mass, particles created from the vacuum
And then ... )
Steve: Now its time to play TOTALL....... Y BOGUS. We are going to mix it up a little this week. Usually we have four science stories, but only three are true. This week, to make it easy, all the stores are fake. So don't bother to see if you know which story is TOTALL....... Y BOGUS.
Story number 1: The LHC will destroy the world.
Story number 2: From the time he was a young boy, Frank Wilczek was educated at the finest private schools money can buy.
Story number 3: The Hadron is in fact named after the Roman emperor Hadron.
And story number 4: George Musser is a complete idiot.
Story 1 is TOTALL....... Y BOGUS. As we noted, the LHC will not destroy the world and as George Musser wrote to me after we recorded the interview, "I said something to the effect that scientists had stocked [stoked] concerns about black holes by saying the LHC would create particles not seen since the big bang, but those particles have been seen since the big bang, namely in natural processes such as cosmic ray collisions; therefore if black holes posed a threat, the universe would already be a goner."
Story 2 is TOTALL....... Y BOGUS. Frank Wilczek went to public schools in New York City. He is a graduate of Martin Van Buren High School in Queens; so is futurist Ray Kurzweil—listen to the June 18th, 2008 episode of Science Talk for discussion about why Ray Kurzweil will probably not achieve his dream of uploading all the contents of his brain.
And story 3 is TOTALL....... Y BOGUS. There was no Roman emperor Hadron. There was a Roman emperor, Hadrian, and you can still see his wall today in northern England. Hadrian's Wall was roughly four times the length of the LHC's beam path.
And story 4 is TOTALL....... Y BOGUS. George Musser is not a complete idiot. But he is the author of The Complete Idiot's Guide to String Theory. For more on the book, check out our conversation on the July 16th, 2008 episode of Science Talk. George is in fact a very bright guy and a terrific dancer.
Well that's it for this edition of the weekly SciAm podcast. Visit http://www.SciAm.com for all the latest science news, videos, and blogs. We gave you two episodes this week, so we are taking next week off. We'll back with the fresh episode on September 24th. For Science Talk, the weekly podcast of Scientific American, I'm Steve Mirsky. Thanks for clicking on us.