Edge 111— February 13, 2003

(16,000 words)


Additional spatial dimensions may seem like a wild and crazy idea at first, but there are powerful reasons to believe that there really are extra dimensions of space. One reason resides in string theory, in which it is postulated that the particles are not themselves fundamental but are oscillation modes of a fundamental string.

LISA RANDALL is a professor of physics at Harvard University, where she also earned her PhD (1987). She was a President's Fellow at the University of California at Berkeley, a postdoctoral fellow at Lawrence Berkeley Laboratory, and a junior fellow at Harvard before joining the MIT faculty in 1991. Between 1998 and 2000, she had a joint appointment at Princeton and MIT as a full professor, and she moved to Harvard as a full professor in 2001. Her research in theoretical high energy physics is primarily related to exploring the physics underlying the standard model of particle physics. This has involved studies of supersymmetry and, most recently, extra dimensions of space.

Lisa Randall's Edge Bio Page

Amidst all the self serving rhetoric, I think Edge should contribute its own obsequy. The people who died were scientists. Whatever else they may have believed in, their goal was to learn and to explore.

Contributors (to date): Oliver Morton, Gregory Benford, George Dyson, Nicholas Humphey, Paul Davies, Martin Rees

"Big, deep and ambitious questions....breathtaking in scope. Keep watching The World Question Center." — New Scientist


"What are the pressing scientific issues for the nation and the world, and what is your advice on how I can begin to deal with them?" — GWB

New Philip Brockman • George Smoot • John McWhorter • Sherry Turkle • Gregory Benford • Vera John-Steiner • Paul MacCready • Margaret Wertheim


The Engine of Prosperity
Academics Demand a New Science Policy from Bush

by Andrian Kreye
January 14, 2003

Because the last decade brought forth not only scientific successes, but also a new scientific culture, the struggle for the future no longer takes place in privileged circles, but on the public stage...The worldview with the greatest profile in this regard is the "third culture," because it attempts to find scientific answers to the most important questions facing humanity. New York literary agent John Brockman coined the term...and conducts its most important debating club on his internet platform, Edge (http://www.edge.org).

Amidst all the self serving rhetoric, I think Edge should contribute its own obsequy. The people who died were scientists. Whatever else they may have believed in, their goal was to learn and to explore.


Nicholas Humphrey

The death of the seven astronauts aboard the space shuttle Columbia has been represented by the media as a tragedy not just for the individuals but for American values—as if democracy, liberty and Christianity were part of the payload. Amidst all the self serving rhetoric, I think Edge should contribute its own obsequy. The people who died were scientists. Whatever else they may have believed in, their goal was to learn and to explore. Speaking at their press conference from space on Friday, each in turn talked of how he or she felt themselves a part of the trans human quest to know more and go further—and each emphasised how the view from space revealed the absurdity of narrow political or religious divisions. The scientific aims of the mission may not have been large, but the human spirit that flew with it was. I hope Edge will want to salute these fellow travellers on our own terms.

NICHOLAS HUMPHREY. School Professor at the London School of Economics and Professor of Psychology at the New School for Social Research is a theoretical psychologist, His books include A History of the Mind,and The Mind Made Flesh.

Contributors (to date): Oliver Morton, Gregory Benford, George Dyson, Nicholas Humphey, Paul Davies, Martin Rees

Most recent first

Martin Rees

I recall attending a lecture given, back in the 1960s, by John Glenn, the first American to go into orbit. A questioner asked him what went through his mind while he was crouched in the rocket nose-cone, awaiting blastoff. He wryly replied "I was thinking that the rocket had twenty thousand components, and each was made by the lowest bidder".

Glenn was aware of the risk he was taking—so surely, would have been the astronauts who perished in Columbia. But their fate injects a dose of reality: space travel is not a routine exercise. We need to ask—as we do of any pioneering venture—whether the goals of manned spaceflight are inspiring or valuable enough to justify the hazards involved.

The Shuttle's 98 percent success record—two disasters in just over a hundred flights—is actually rather good by space standards. Must unmanned rockets have a worse record. (The French Ariane V rocket had two catastrophic failures in less than a dozen flights).

We don't yet know whether last week's accident could have been avoided by better maintenance. I suspect it could. But even with optimal precautions, the risks of going into space will remain high compared to those that most of us willingly and routinely accept.

Publicly-funded astronauts are, in a sense, acting on our behalf. We feel uneasy about civilians bearing such risks, when the issues aren't of life or death urgency, but primarily science or exploration. Nonetheless, some individuals—wealthy amateur mountaineers who join guided parties to climb Everest, or test pilots—willingly do things that are at least as dangerous as a Shuttle flight.

When I am asked about the case for sending people into space, my answer is that as a scientist I'm against it, but as a human being I'm in favour. Practical activities in space—for communications, science, weather forecasting and navigation)—are better (and far more cheaply) carried out by computers and robots. I am nonetheless an enthusiast for space exploration as a long-range adventure for (at least a few) humans .

The next humans to walk on the Moon may be Chinese—only China seems to have the resources, the dirigiste government, and the willingness to undertake a risky Apollo-style programme. I hope Americans or Europeans will sometime venture to the Moon and beyond, but this will be in a very different style, and with different motives..

The kind of vibrant manned programme that I'd one day like to see will require changes in techniques and style. First, costs must come down. Second, there must be an overt acceptance that the enterprise is dangerous.

A role model for the future astronaut is not a NASA employee, nor even a military test pilot, but someone more in the mould of Steve Fossett, the wealthy "serial adventurer" who, after several expensive failures, succeeded in his solo round-the-world balloon flight. He has a craving for arduous challenges, and is now trying to beat altitude and endurance records for gliders. In each venture, Fossett must knowingly accept accepts a risk of at least 1 percent. Were he to come to a sad end, we would mourn a brave and resourceful man, but there would not be a national trauma. We would know that he willingly too the risks, and it was perhaps the way he wanted to go. Future expeditions to the Moon and beyond will only, I think be politically and financially feasible if they are spearheaded by individuals prepared to accept high risks, and perhaps even privately funded.

Dennis Tito and Mark Shuttleworth each spent 20 million dollars in return for a week in the International Space Station. A line-up of others was willing to follow them, even at that price. Such people won't, in the long run, restrict themselves to the role of passengers passively circling the Earth: they will yearn to go further.

Manned expeditions into deep space may one day be fundable by private consortia. Larry Ellison, who bankrolled a yachting challenge for the Americas Cup would already have the resources to initiate a cut-price project to take humans beyond Earth orbit.

The intrepid voyagers who set out from Europe in the 15th and 16th century to explore the then-open frontiers of our own world were mainly bankrolled by monarchs, in the hope of recouping exotic merchandise or colonising new territory. Some later expeditions, for instance Captain Cook's three 18th century voyages to the South Seas, were publicly funded, their mission being to survey new territory, discover new plants, and make astronomical measurements. For some early explorers—generally the most foolhardy of all—the enterprise was primarily a challenge and adventure: the motivation of present-day mountaineers, balloonists, round-the-world sailors and the like.

The first travellers to Mars (maybe thirty years from now), or the first long-term denizens of a lunar base, could be impelled by this same mix of motives. They would confront hostile environments: nowhere in our Solar system offers an environment even as clement as the Antarctic or the deep ocean. However, no space travellers would be venturing into the unknown to the extent that the great terrestrial navigators were: those early pioneers had far less foreknowledge of what they might encounter in the regions where ancient cartographers wrote "here be dragons". Nor would space travellers be denied contact with home, any more than explorers and lone sailors now are. There would admittedly be about a 30 minute turnaround for messages to and from Mars, because it takes that long for a radio signal to traverse the hundreds of millions of miles distance. But that is as nothing compared to the isolation of traditional explorers.

The stakes will be high for space explorers: they will be opening up entire new worlds, Maybe some would accept—as many Europeans willingly did when they set out for the New World—that there would be no return. A Martian base would develop more quickly if those constructing it were content with one way tickets.

The mountaineers George Mallory and Andrew Irvine both perished on Mount Everest in 1924, during a celebrated early attempt to reach its summit. A stone tablet in Irvine's memory bears a text from Pericles's famous funeral oration (in Hobbes's translation) .

"They are most rightly reputed valiant who perfectly understand what is dangerous and what is easy, but are not thereby diverted from adventuring".

This sentiment, I believe, would have resonated with the Columbia astronauts. In future decades, if humans venture to the Moon and beyond, they will have to go in this same spirit.

SIR MARTIN REES is Royal Society Professor at Cambridge University, Fellow of Kings College, and the UK's Astronomer Royal. He books include Just Six Numbers; Our Cosmic Habitat; and Our Final Hour: A Scientist's Warning: How Terror, Error, and Environmental Disaster Threaten Humankind's Future In This Century—On Earth and Beyond (forthcoming, March).

Paul Davies

I once met an American scientist (in Tucson) who claimed he trained (secretly) for a one way journey to the moon. The program was deemed politically unacceptable, and scrapped. There may be some interesting history to this.

PAUL DAVIES is a physicist, writer and broadcaster, now based in South Australia
Author of The Mind of God; Are We Alone?; The Fifth Miracle; and The Last Three Minutes.

Nicholas Humphrey

I've been dwelling on George's suggestion of a one way manned voyage to Mars. I think George is right that it has the potential to capture the world's attention as nothing ever has done—science, religion, sex, adventure, reality tv, all rolled into one. The child of Shakespeare, Newton, Darwin, Freud and Einstein. Why don't we make this an Edge project? John Brockman has the best of all address books. Edge could make it happen!

George Dyson

When I think of the "Columbia", I still think of the 213-ton "Columbia Rediviva," launched in Plymouth, Massachussetts in 1787, in which Captain Robert Gray explored the Northwest Coast. There could be no better monument to the crew of the recent Columbia than to make their sacrifice a decisive turning point in truly expanding Earth's biology, technology, and biotechnology out into the solar system.

There's no shortage of ways to to go about this. Here's my (non-original) suggestion.

Let the new "Columbia Rediviva" (Columbia Revived) be a ship built to deliver seven human beings on a (for the time being) one-way voyage to Mars. We all know that technically, the hard part is getting back. But if we could get seven people there, the world would unite as one in sending these first colonists all possible support, and, eventually, developing the infrastructure that might allow people to go back and forth.

GEORGE DYSON, a historian among futurists, has been excavating the history and prehistory of the digital revolution going back 300 years. He is the author Baidarka: The Kayak; Darwin Among the Machines; and Project Orion: The True Story of the Atomic Spaceship.

Gregory Benford

Beyond The Shuttle

A friend at NASA's Marshall Space flight Center in Huntsville, Alabama told me today that all his engineer friends were working on their resumes. After the Challenger disaster, NASA dithered for 2.5 years before using the shuttle again. How long this time?

Quite probably, a year—if ever. This second wreck calls into question the entire shuttle program. Voices already are calling for a wholly new approach. The shuttle has the worst safety record of any launch vehicle, and is the most expensive, costing half a billion dollars per mission.

And we now contemplate a war in Iraq that depends on our technical prowess. I doubt that Americans will be moved to doubt our military, just because an advanced spacecraft fell out of a clear blue sky. We are tougher than we may look—and more resolute. The country is reasonably united, and yet again the president has responded with the right sense of gravity. He does disaster well.

Still, it is a good time to reassess. Early results from the telemetry and the huge debris field suggest that the thermal tiles failed. One amateur observer saw something blowing off the shuttle as it passed over California, possibly red-hot tiles. We know that a piece of foam blew off the fuel tanks at launch, striking the shuttle's left wing, a location that seems implicated in the heating spike that the telemetry recorded just before the craft began to slew and tumble.

Reentry is a tricky negotiation between gravity and aerodynamics. Controlling descent angle is important to reduce mechanical and thermal stress on the spacecraft, and an error in the on-board computers can allow the angle to get so steep that the craft breaks apart. (Multiple computers should reduce the risk, but that has not saved computer-run aircraft like the SAAB 39 Gripen from the occasional crash.)

Whatever the fault, tiles or computers or human error, the crash occurred at what many engineers thought was the most dangerous portion of a shuttle's flight. This is not a fluke; the system was vulnerable, and it failed yet again.

Perhaps the only good thing about this disaster is that it will prompt NASA to rethink the design of manned spacecraft from first principles. Foremost is that the more complex a spacecraft is, the more things can go wrong.

The safest manned descent module was also the simplest: the Soviet "sharik" descent capsule, which was used by Vostok and Voskhod craft, and also in many unmanned missions since. It was just a sphere with the center of gravity on the side with the thickest ablative thermal shielding, so it was self-stabilising. Even if the retrorockets failed to separate, it could re-enter safely.

Simple ballistic craft that do not fly are also (relatively) simple. With a spaceplane like the shuttle, however, you are not only committed to a complex shape, you are also committed to using brittle ceramic materials for thermal shielding. The first item on NASA's agenda will be to revisit the tiles issue.

The ceramic tiles not only make overhaul very time-consuming and expensive—specialists affix each tile by hand, managing to do a few per day, and there are thousands— they are also literally impossible to check for inner defects. Unlike metal components, you cannot test them for small cracks that may cause failure.

One way around this is to use many small ceramic tiles, so the spacecraft can survive losing individual tiles. But if several adjacent tiles are lost, it will cause catastrophic failure during reentry. Maybe that happened; it is consistent with what we know now (or are likely to know for several months).

A second line of defense is to have the crew in a detachable unit that can land safely. This would be straightforward in a ballistic craft, but with an aerodynamic spaceplane it is difficult to squeeze such a unit into the nose. On the B-58 bomber the crew had small individual pods that enabled them to eject safely at supersonic speeds, but the weight penalty ruled out this option for the shuttle.

Ideally, you need a descent module that can take a lot of punishment. But a big spaceplane would get impossibly heavy if it was stressed for this. This is another argument for small sixties-era crew capsules.

Ironically, the Soviet "Buran" shuttle could lift loads to orbit without any crew at all, and might make a viable alternative to the US shuttle. But the only remaining craft got badly damaged when a corroded hangar roof fell down on it last year—a symbol of the Russian program's decay.

The safest manned spacecraft built was also among the cheapest and simplest. The lunar lander used pressurized tanks, eliminating the need for turbo pumps, and the fuel and oxidizer self-ignited when mixed, making the engine very reliable.

NASA considered mass-producing similar, simple rockets in the sixties as an option to make space flight cheaper. Political considerations favored the more spectacular spaceplane solution. To date, this decision has killed two shuttle crews and cost billions.

In the end, the next months will try NASA as never before. It has tried to convince its public that going into space is safe, when it is not. Once is an accident, twice is a defect.

The shuttle's justification these days has been its role in supporting a space station that now does little science. The station runs with the minimum crew of three, to save money while forgetting science. The Russian Soyez vehicle could cycle crews and probably will be used to bring down the three up there now.

The station program can limp along for a few years with two flights a year, to cycle crews every half year and not abandon the station entirely. A Russian Proton rocket can continue to boost the station up as its orbit decays from atmospheric friction, as we now do routinely.

This can go on until NASA can decide what to do. Its habit is not to be truly decisive, but now its back is to the wall. It must confront the big question:

What is the American destiny in space? The station is not a destination; it is a tool. But for what?

NASA has played up the station as "a stepping-stone to the planets" — but it cannot perform the two experiments we know must be done before any manned ventures beyond Low Earth Orbit begin.

These are, first, development of a true closed biosphere in low or zero gravity. The station recycles only urine; otherwise, it is camping in space, not truly living there.

Second, we must develop centrifugal gravity. Decades of trials show clearly that zero-g is very bad for us. The Russians who set the endurance records in space have never fully recovered. Going to Mars demands that crews arrive after the half year journey able to walk, at least. No crew returning from space after half a year ever have, even for weeks afterward. So we must get more data, between one gravity and none. Mars has 0.38 g; how will we perform there? Nobody knows.

Spinning a habitat at the other end of a cable, counter-balanced by a dead mass like a missile upper stage, is the obvious first way to try intermediate gravities. The International Space Station has tried very few innovations, and certainly nothing as fruitful as a centrifugal experiment. Until a livelier spirit animates the official space program, the tough jobs of getting into orbit cheaply, and living there self sufficiently, will probably have to be done by private interests who can angle a profit from it. But not right away.

This is an historic moment, one of great opportunity. NASA can either rise to the challenge and scrap the shuttle, or just muddle along. An intermediate path would use the shuttles on a reduced schedule, while developing a big booster capable of hauling up the big loads needed to build more onto the station. This would be cost-effective and smart.

The past Director of NASA said to me a few years ago that he thought the agency had about a decade to prove itself. Around 2010 the Baby Boomers will start to retire and the Federal budget will come under greater pressure. Space could go into a slow, agonizing withering. He thought this was a distinct possibility if NASA did no more than fly around in cycles over our heads. "It has to go somewhere else," he said.

The obvious target that has huge scientific possibility is Mars. Did life arise there, and does it persist beneath the bleak surface? No robot remotely within our capability can descend down a thermal vent or drill and find an answer. Only humans are qualified to do the science necessary, on the spot.

A Mars expedition would be the grandest exploit open to the the 21st Century. It would take about 2.5 years, every day closely monitored by a huge Earthside audience and fraught with peril.

This is what we should be doing. Such an adventure would resonate with a world beset by wars and woes. It has a grandeur appropriate to the advanced nations, who should do it together.

The first step will be getting away from the poor, clunky shuttle, a beast designed 30 years ago and visibly failing now. How we respond to the challenge of this failure will tell the tale for decades to come, and may become a marking metaphor for the entire century.

As well, the engineers at NASA would be overjoyed to have a larger prospect before them, something better than patching up an aging shuttle that, in the end, was going nowhere.

GREGORY BENFORD is a professor of physics and astronomy at the University of California, Irvine, a long-time advisor to NASA, and a novelist. His books include Timescape and The Martian Race.

Oliver Morton

The most fitting salute I can imagine for the Columbia seven would be a continued—indeed expanded, in scope if not in budget—space programme; but not a continuation of the space programme America has today.

Most people who believe that expanding the shared human world beyond the planet of its birth is a good idea have a sad belief that if they give up the shuttle there will never be another manned programme. There is a strange dissonance between the grandeur of the vision and the insistence that its survival depends on never giving up on the programme as it is today.

It's time to resolve that dissonance by providing human spaceflight with a mission other than its own continuation (which has been the de facto mission since Nixon approved the programme) and re-inventing the programme in the context of that mission. I think solar system exploration should be the mission; an ambitious robotic and human partnership with the human side focused, at least to begin with, on Mars. Understanding the earth and its life as a system that has developed—and will continue to develop—over history is a crucial goal for the twentieth century. Learning the history of a similar but different possibly-once-living world could be crucial to that.

So if I was President Bush I would reaffirm my commitment to space by mothballing the last three shuttles and the station (after finding the best way to boost it into a century-stable orbit). I'd then use the annual $6 billion thus saved for a serious solar-system exploration programme. Under that heading I would put: the design of a heavy lift vehicle in the Energia-plus/Saturn V class, capable of launching very large payloads to earth orbit and substantial ones to Mars; a production facility capable of producing those rockets at a rate of two or so a year; development work with others (eg Europe, Russia, India, Japan) on vehicles that would use that capacity for Mars missions along the lines of those that Robert Zubrin has proposed, though not necessarily with exactly that profile; and safe space nuclear power and advanced ion engines to make use of that power, initially to do some impressive robot missions but with planned growth to allow eventual use for manned missions.

I'd use this material for a series of humans-to-Mars precursor missions in which robots would go to Mars and humans would start off practising things nearer to earth. The robot missions would increase knowledge of relevant environmental conditions (for example, set up a weather network) and also demonstrate necessary technologies such as in-situ fuel production using a reactor. The human program would use launched-in-one-piece Skylab-type spacecraft to check out the unknowns about Mars flight. I think relatively short duration Skylab type missions specifically designed to do this represent a significant advantage over the use of today's long-duration space station. Such missions, unlike today's station, could test simulated gravity systems, both systems using centrifuges on board for individual exercise and those that require spinning entire spacecraft on a tether. They would also serve as testbeds for the development of flight hardware for the cruise and landing parts of a Mars mission. And they offer a way of parcelling out the effort between different nations, with different units built in different places. (On international cooperation, and Nick Humphrey's mention of the meaninglessness of borders in space, I'm reminded of the exchange between two astronauts in Niven and Pournelle's "Lucifer's Hammer": "'So you can't see the international borders from space and everyone tries to make a big point of it. If we keep that up, you know what'll happen?' Rock laughed 'Yeah. Everyone's gonna start painting their borders in neon orange a mile wide'")

These Skylab type craft might be used for some beyond-earth-orbit missions, as well as in orbit tests. One such mission might be a near earth asteroid rendezvous and subsequent testing of a low-thrust long-lifetime engine to change the asteroids course, as suggested by Piet Hut and the B612 Foundation. Another might be a trip to Mars orbit, where the crew could do some intensive service work with robots tele-operated in real time but wouldn't have to function outside microgravity. Then start the landings, going to sites that the robots have shown to be interesting that will repay detailed fieldwork. On the timing I'm thinking roughly ten years of development and ten years of trying things out with people in orbit before we start doing the Mars stuff, but with a permanently crewed Mars base developed fairly quickly thereafter (ie in the third decade). That's my feeling for the sort of rate at which a $6 billion (plus non American funds) programme might progress happily.

A programme like this would require no shuttles. It could get by with Soyuz capsules and, later, more advanced landing capsules. And so I would not rush into the development of a replacement shuttle. Instead I'd fly a variety of prototypes for orbital space planes. We need to try a lot more technologies, philosophies and designs in real conditions before even thinking about locking in to a concept for a new reusable TSTO or SSTO machine. But I would make this a considerably lower priority than solar system exploration. We can do the most exciting stuff without it.

It's possible that the USAF will want a manned spaceplane of its own—among other things, the men in blue suits may find the idea of Chinese astronauts being able to go up and rendezvous with US satellites unchecked a little disturbing. If the USAF wants something soon, then let them develop it to their own specifications and out of their own budget; many of the compromises that made the shuttle so complex and vulnerable came from USAF requirements. If such a spaceplane then becomes useful for the solar system programme, then I'm sure they would let us borrow a coupleŠ

If the airforce builds a spaceplane, though, that does not necessarily mean that NASA should do all the other stuff. The shuttle programme is so central to NASA that a post-shuttle restart might make a new organisation desirable; I'd be interested to hear what others think on that.

The Scottish science fiction writer Ken MacLeod provided this epitaph in the wake of the Columbia:

Husband, McCool, Anderson, Brown, Chawla, Clark, Ramon.
Komarov, Grissom, White, Chaffee, Dobrovolsky, Volkov, Patsayev,
Resnick, Scobee, Smith, McNair, McAuliffe, Jarvis, Onizuka.
These names will be written under other skies.

It's a beautiful thought. But the other skies are not going to be reached any time soon through a continued shuttle programme.

OLIVER MORTON is a freelance writer who used to edit Wired UK, and previously worked at The Economist, spending almost five years as Science and Technology Editor. He is the author of Mapping Mars.


Additional spatial dimensions may seem like a wild and crazy idea at first, but there are powerful reasons to believe that there really are extra dimensions of space. One reason resides in string theory, in which it is postulated that the particles are not themselves fundamental but are oscillation modes of a fundamental string.

Lisa Randall: EdgeVideo
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LISA RANDALL is a professor of physics at Harvard University, where she also earned her PhD (1987). She was a President's Fellow at the University of California at Berkeley, a postdoctoral fellow at Lawrence Berkeley Laboratory, and a junior fellow at Harvard before joining the MIT faculty in 1991. Between 1998 and 2000, she had a joint appointment at Princeton and MIT as a full professor, and she moved to Harvard as a full professor in 2001. Her research in theoretical high energy physics is primarily related to exploring the physics underlying the standard model of particle physics. This has involved studies of supersymmetry and, most recently, extra dimensions of space.

Lisa Randall's Edge Bio Page


LISA RANDALL: Particle physics has contributed to our understanding of many phenomena, ranging from the inner workings of the proton to the evolution of the observed universe. Nonetheless, fundamental questions remain unresolved, motivating speculations beyond what is already known. These mysteries include the perplexing masses of elementary particles; the nature of the dark matter and dark energy that constitute the bulk of the universe; and what predictions string theory, the best candidate for a theory incorporating both quantum mechanics and general relativity, makes about our observed world. Such questions (along with basic curiosity) have prompted my excursions into theories that might underlie currently established knowledge. Some of my most recent work has been on the physics of extra dimensions of space and has proved rewarding beyond expectation.

Particle physics addresses questions about the forces we understand█the electromagnetic force, the weak forces associated with nuclear decay, and the strong force that binds quarks together into protons and neutrons█but we still have to understand how gravity fits into the picture. String theory is the leading contender, but we don't yet know how string theory reproduces all the particles and physical laws we actually see. How do we go from this pristine, beautiful theory existing in ten dimensions to the world surrounding us, which has only four█three spatial dimensions plus time? What has become of string theory's superfluous particles and dimensions?

Sometimes a fruitful approach to the big, seemingly intractable problems is to ask questions whose possible answers will be subject to experimental test. These questions generally address physical laws and processes we've already seen. Any new insights will almost certainly have implications for even more fundamental questions. For example, we still don't know what gives rise to the masses of the fundamental particles█the quarks, leptons (the electron, for example), and electroweak gauge bosons█or why these masses are so much less than the mass associated with quantum gravity. The discrepancy is not small: The two mass scales are separated by sixteen orders of magnitude! Only theories that explain this huge ratio are likely candidates for theories underlying the standard model. We don't yet know what that theory is, but much of current particle physics research, including that involving extra dimensions of space, attempts to discover it. Such speculations will soon be explored at the Large Hadron Collider in Geneva, which will operate at the TeV energies relevant to particle physics. The results of experiments to be performed there should select among the various proposals for the underlying physical description in concrete and immediate ways. If the underlying theory turns out to be either supersymmetry or one of the extra dimension theories I will go on to describe, it will have deep and lasting implications for our conception of the universe.

Right now, I'm investigating the physics of the TeV scale. Particle physicists measure energy in units of electron volts. TeV means a trillion electron volts. This is a very high energy and challenges the limits of current technology, but it is low from the perspective of quantum gravity, whose consequences are likely to show up only at energies sixteen orders of magnitude higher. This energy scale is interesting because we know that the as-yet-undiscovered part of the theory associated with giving elementary particles their masses should be found there.

Two of the potential explanations for the huge disparity in energy scales are supersymmetry and the physics of extra dimensions. Supersymmetry, until very recently, was thought to be the only way to explain physics at the TeV scale. It is a symmetry that relates the properties of bosons to those of their partner fermions (bosons and fermions being two types of particles distinguished by quantum mechanics). Bosons have integral spin and fermions have half-integral spin, where spin is an internal quantum number. Without supersymmetry, one would expect these two particle types to be unrelated. But given supersymmetry, properties like mass and the interaction strength between a particle and its supersymmetric partner are closely aligned. It would imply for an electron, for example, the existence of a corresponding superparticle█called a selectron, in this case█with the same mass and charge. There was and still is a big hope that we will find signatures of supersymmetry in the next generation of colliders. The discovery of supersymmetry would be a stunning achievement. It would be the first extension of symmetries associated with space and time since Einstein constructed his theory of general relativity in the early twentieth century. And if supersymmetry is right, it is likely to solve other mysteries, such as the existence of dark matter. String theories that have the potential to encompass the standard model seem to require supersymmetry, so the search for supersymmetry is also important to string theorists. Both for these theoretical reasons and for its potential experimental testability, supersymmetry is a very exciting theory.

However, like many theories, supersymmetry looks fine in the abstract but leaves many questions unresolved when you get down to the concrete details of how it connects to the world we actually see. At some energy, supersymmetry must break down, because we haven't yet seen any "superpartners." This means that the two particle partners█for example, the electron and the selectron█cannot have exactly the same mass; if they did, we would see both. The unseen partner must have a bigger mass if it has so far eluded detection. We want to know how this could happen in a way consistent with all known properties of elementary particles. The problem for most theories incorporating supersymmetry-breaking is that all sorts of other interactions and decays are predicted which experiment has already ruled out. The most obvious candidates for breaking supersymmetry permit the various kinds of quarks to mix together, and particles would have a poorly defined identity. The absence of this mixing and the retention of the various quark identities is a stringent constraint on the content of the physical theory associated with supersymmetry-breaking, and is one important reason that people were not completely satisfied with supersymmetry as an explanation of the TeV scale. To find a consistent theory of supersymmetry requires introducing physics that gives masses to the supersymmetric partners of all the particles we know to exist, without introducing interactions we don't want. So it's reasonable to look around for other theories that might explain why particle masses are associated with the TeV energy scale and not one that is sixteen orders of magnitude higher.

There was a lot of excitement when it was first suggested that extra dimensions provide alternative ways to address the origin of the TeV energy scale. Additional spatial dimensions may seem like a wild and crazy idea at first, but there are powerful reasons to believe that there really are extra dimensions of space. One reason resides in string theory, in which it is postulated that the particles are not themselves fundamental but are oscillation modes of a fundamental string. The consistent incorporation of quantum gravity is the major victory of string theory. But string theory also requires nine spatial dimensions, which, in our observable universe, is obviously six too many. The question of what happened to the six unseen dimensions is an important issue in string theory. But if you're coming at it from the point of view of the relatively low-energy questions, you can also ask whether extra dimensions could have interesting implications in our observable particle physics or in the particle physics that should be observable in the near future. Can extra dimensions help answer some of the unsolved problems of three-dimensional particle physics?

People entertained the idea of extra dimensions before string theory came along, although such speculations were soon forgotten or ignored. It's natural to ask what would happen if there were different dimensions of space; after all, the fact that we see only three spatial dimensions doesn't necessarily mean that only three exist, and Einstein's general relativity doesn't treat a three-dimensional universe preferentially. There could be many unseen ingredients to the universe. However, it was first believed that if additional dimensions existed they would have to be very small in order to have escaped our notice. The standard supposition in string theory was that the extra dimensions were curled up into incredibly tiny scales█10 33 centimeters, the so-called Planck length and the scale associated with quantum effects becoming relevant. In that sense, this scale is the obvious candidate: If there are extra dimensions, which are obviously important to gravitational structure, they'd be characterized by this particular distance scale. But if so, there would be very few implications for our world. Such dimensions would have no impact whatsoever on anything we see or experience.

From an experimental point of view, though, you can ask whether extra dimensions really must be this ridiculously small. How large could they be and still have escaped our notice? Without any new assumptions, it turns out that extra dimensions could be about seventeen orders of magnitude larger than 10-33 cm. To understand this limit requires more fully understanding the implications of extra dimensions for particle physics.

If there are extra dimensions, the messengers that potentially herald their existence are particles known as Kaluza-Klein modes. These KK particles have the same charges as the particles we know, but they have momentum in the extra dimensions. They would thus appear to us as heavy particles with a characteristic mass spectrum determined by the extra dimensions' size and shape. Each particle we know of would have these KK partners, and we would expect to find them if the extra dimensions were large. The fact that we have not yet seen KK particles in the energy regimes we have explored experimentally puts a bound on the extra dimensions' size. As I mentioned, the TeV energy scale of 10-16 cm has been explored experimentally. Since we haven't yet seen KK modes and 10-16 cm would yield KK particles of about a TeV in mass, that means all sizes up to 10-16 are permissible for the possible extra dimensions. That's significantly larger than 10 33 cm, but it's still too small to be significant.

This is how things stood in the world of extra dimensions until very recently. It was thought that extra dimensions might be present but that they would be extremely small. But our expectations changed dramatically after 1995, when Joe Polchinski, of the University of California at Santa Barbara, and other theorists recognized the importance of additional objects in string theory called branes. Branes are essentially membranes█lower-dimensional objects in a higher-dimensional space. (To picture this, think of a shower curtain, virtually a two-dimensional object in a three-dimensional space.) Branes are special, particularly in the context of string theory, because there's a natural mechanism to confine particles to the brane; thus not everything need travel in the extra dimensions even if those dimensions exist. Particles confined to the brane would have momentum and motion only along the brane, like water spots on the surface of your shower curtain.

Branes allow for an entirely new set of possibilities in the physics of extra dimensions, because particles confined to the brane would look more or less as they would in a three-plus-one-dimension world; they never venture beyond it. Protons, electrons, quarks, all sorts of fundamental particles could be stuck on the brane. In that case, you may wonder why we should care about extra dimensions at all, since despite their existence the particles that make up our world do not traverse them. However, although all known standard-model particles stick to the brane, this is not true of gravity. The mechanisms for confining particles and forces mediated by the photon or electrogauge proton to the brane do not apply to gravity. Gravity, according to the theory of general relativity, must necessarily exist in the full geometry of space. Furthermore, a consistent gravitational theory requires that the graviton, the particle that mediates gravity, has to couple to any source of energy, whether that source is confined to the brane or not. Therefore, the graviton would also have to be out there in the region encompassing the full geometry of higher dimensions█a region known as the bulk█because there might be sources of energy there. Finally, there is a string-theory explanation of why the graviton is not stuck to any brane: The graviton is associated with the closed string, and only open strings can be anchored to a brane.

A scenario in which particles are confined to a brane and only gravity is sensitive to the additional dimensions permits extra dimensions that are considerably larger than previously thought. The reason is that gravity is not nearly as well tested as other forces, and if it is only gravity that experiences extra dimensions, the constraints are much more permissive. We haven't studied gravity as well as we've studied most other particles, because it's an extremely weak force and therefore more difficult to precisely test. Physicists have showed that even dimensions almost as big as a millimeter would be permitted, if it were only gravity out in the higher-dimensional bulk. This size is huge compared with the scales we've been talking about. It is a macroscopic, visible size! But because photons (which we see with) are stuck to the brane, too, the dimensions would not be visible to us, at least in the conventional ways.

Once branes are included in the picture, you can start talking about crazily large extra dimensions. If the extra dimensions are very large, that might explain why gravity is so weak. (Gravity might not seem weak to you, but it's the entire earth that's pulling you down; the result of coupling an individual graviton to an individual particle is quite small. From the point of view of particle physics, which looks at the interactions of individual particles, gravity is an extremely weak force.) This weakness of gravity is a reformulation of the so-called hierarchy problem█that is, why the huge Planck mass suppressing gravitational interactions is sixteen orders of magnitude bigger than the mass associated with particles we see. But if gravity is spread out over large extra dimensions, its force would indeed be diluted. The gravitational field would spread out in the extra dimensions and consequently be very weak on the brane█an idea recently proposed by theorists Nima Arkani Hamed, Savas Dimopoulos, and Gia Dvali. The problem with this scenario is the difficulty of explaining why the dimensions should be so large. The problem of the large ratio of masses is transmuted into the problem of the large size of curled-up dimensions.

Raman Sundrum, currently at Johns Hopkins University, and I recognized that a more natural explanation for the weakness of gravity could be the direct result of the gravitational attraction associated with the brane itself. In addition to trapping particles, branes carry energy. We showed that from the perspective of general relativity this means that the brane curves the space around it, changing gravity in its vicinity. When the energy in space is correlated with the energy on the brane so that a large flat three-dimensional brane sits in the higher-dimensional space, the graviton (the particle communicating the gravitational force) is highly attracted to the brane. Rather than spreading uniformly in an extra dimension, gravity stays localized, very close to the brane.

The high concentration of the graviton near the brane█let's call the brane where gravity is localized the Planck brane█leads to a natural solution to the hierarchy problem in a universe with two branes. For the particular geometry that solves Einstein's equations, when you go out some distance in an extra dimension, you see an exponentially suppressed gravitational force. This is remarkable because it means that a huge separation of mass scales█sixteen orders of magnitude█can result from a relatively modest separation of branes. If we are living on the second brane (not the Planck brane), we would find that gravity was very weak. Such a moderate distance between branes is not difficult to achieve and is many orders of magnitude smaller than that necessary for the large-extra-dimensions scenario just discussed. A localized graviton plus a second brane separated from the brane on which the standard model of particle physics is housed provides a natural solution to the hierarchy problem█the problem of why gravity is so incredibly weak. The strength of gravity depends on location, and away from the Planck brane it is exponentially suppressed.

This theory has exciting experimental implications, since it applies to a particle physics scale█namely, the TeV scale. In this theory's highly curved geometry, Kaluza-Klein particles█those particles with momentum in the extra dimensions█would have mass of about a TeV; thus there is a real possibility of producing them at colliders in the near future. They would be created like any other particle and they would decay in much the same way. Experiments could then look at their decay products and reconstruct the mass and spin that is their distinguishing property. The graviton is the only particle we know about that has spin 2. The many Kaluza-Klein particles associated with the graviton would also have spin 2 and could therefore be readily identified. Observation of these particles would be strong evidence of the existence of additional dimensions and would suggest that this theory is correct.

As exciting as this explanation of the existence of very different mass scales is, Raman and I discovered something perhaps even more surprising. Conventionally, it was thought that extra dimensions must be curled up or bounded between two branes, or else we would observe higher-dimensional gravity. The aforementioned second brane appeared to serve two purposes: It explained the hierarchy problem because of the small probability for the graviton to be there, and it was also responsible for bounding the extra dimension so that at long distances (bigger than the dimension's size) only three dimensions are seen.

The concentration of the graviton near the Planck brane can, however, have an entirely different implication. If we forget the hierarchy problem for the moment, the second brane is unnecessary! That is, even if there is an infinite extra dimension and we live on the Planck brane in this infinite dimension, we wouldn't know about it. In this "warped geometry," as the space with exponentially decreasing graviton amplitude is known, we would see things as if this dimension did not exist and the world were only three-dimensional.

Because the graviton has such a small probability of being located away from the Planck brane, anything going on far away from the Planck brane should be irrelevant to physics on or near it. The physics far away is in fact so entirely irrelevant that the extra dimension can be infinite, with absolutely no problem from a three-dimensional vantage point. Because the graviton makes only infrequent excursions into the bulk, a second brane or a curled-up dimension isn't necessary to get a theory that describes our three-dimensional world, as had previously been thought. We might live on the Planck brane and address the hierarchy problem in some other manner█or we might live on a second brane out in the bulk, but this brane would not be the boundary of the now infinite space. It doesn't matter that the graviton occasionally leaks away from the Planck brane; it's so highly localized there that the Planck brane essentially mimics a world of three dimensions, as though an extra dimension didn't exist at all. A four-spatial-dimensions world, say, would look almost identical to one with three spatial dimensions. Thus all the evidence we have for three spatial dimensions could equally well be evidence for a theory in which there are four spatial dimensions of infinite extent.

It's an exciting but frustrating game. We used to think the easiest thing to rule out would be large extra dimensions, because large extra dimensions would be associated with low energies, which are more readily accessible. Now, however, because of the curvature of space, there is a theory permitting an infinite fourth dimension of space in a configuration that so closely mimics three dimensions that the two worlds are virtually indistinguishable.

If there are differences, they will be subtle. It might turn out that black holes in the two worlds would behave differently. Energy can leak off the brane, so when a black hole decays it might spit out particles into the extra dimension and thus decay much more quickly. Physicists are now doing some interesting work on what black holes would look like if this extra-dimensional theory with the highly concentrated graviton on the brane is true; however, initial inquiries suggest that black holes, like everything else, would look too similar to distinguish the four- and three dimensional theories. With extra dimensions, there are an enormous number of possibilities for the overall structure of space. There can be different numbers of dimensions and there might be arbitrary numbers of branes contained within. Branes don't even all have to be three-plus-one-dimensional; maybe there are other dimensions of branes in addition to those that look like ours and are parallel to ours. This presents an interesting question about the global structure of space, since how space evolves with time would be different in the context of the presence of many branes. It's possible that there are all sorts of forces and particles we don't know about that are concentrated on branes and can affect cosmology.

In the above example, physics everywhere█on the brane and in the bulk█looks three-dimensional. Even away from the Planck brane, physics appears to be three dimensional, albeit with weaker gravitational coupling. Working with Andreas Karch (now at the University of Washington), I discovered an even more amazing possibility: Not only can there be an infinite extra dimension but physics in different locations can reflect different dimensionality. Gravity is localized near us in such a way that it's only the region near us that looks three-dimensional; regions far away reflect a higher-dimensional space. It may be that we see three spatial dimensions not because there really are only three spatial dimensions but because we're stuck to this brane and gravity is concentrated near it, while the surrounding space is oblivious to our lower-dimensional island. There are also some possibilities that matter can move in and out of this isolated four-dimensional region, seeming to appear and disappear as it enters and leaves our domain. These are very hard phenomena to detect in practice, but theoretically there are all sorts of interesting questions about how such a construct all fits together.

Whether or not these theories are right will not necessarily be answered experimentally but could be argued for theoretically, if one or more of them ties into a more fundamental theory. We've used the basic elements found in string theory█namely, the existence of branes and extra dimensions█but we would really like to know if there is a true brane construction. Could you take the very specific branes given by string theory and produce a universe with a brane that localizes gravity? Whether you can actually derive this from string theory or some more fundamental theory is important. The fact that we haven't done it yet isn't evidence that it's not true, and Andreas and I have made good headway into realizing our scenario in string theory. But it can be very, very hard to solve these complicated geometrical set-ups. In general, the problems that get solved, although they seem very complicated, are in many ways simple problems. There is much more work to be done; exciting discoveries await, and they will have implications for other fields.

In cosmology, for instance. Alan Guth's mechanism whereby exponential expansion smooths out the universe works very well, but another possibility has been suggested: a cyclic universe, Paul Steinhardt's idea, wherein a smaller amount of exponential expansion happens many times. Such a theory prompts you to ask questions. First of all, is it really consistent with what we see? The jury's out on that. Does it really have a new mechanism in it? In some sense, the cyclic idea still uses inflation to smooth out the universe. Sometimes it's almost too easy to come up with theories. What grounds your theories? What ties them down? What restricts you from just doing anything? Is there really a new idea there? Do we really have a new mechanism at work? Does it connect to some other, more fundamental theoretical idea? Does it help make that work? Recently I have been exploring the implications of extra dimensions for cosmology. It seems that inflation with extra dimensions works even better than without! What's so nice about this theory is that one can reliably calculate the effect of the extra dimension; no ad hoc assumptions are required. Furthermore, the theory has definite implications for cosmology experiments. All along, I've been emphasizing what we actually see. It's my hope that time and experiments will distinguish among the possibilities.

New Responses Philip Brockman • George Smoot • John McWhorter • Sherry Turkle • Gregory Benford • Vera John-Steiner • Paul MacCready • Margaret Wertheim

The type of research we pursue is not as important as the horizon.

Philip Brockman

Today I retire from 43-year career as a physicist for NASA. I look back to when I began working at Langley Research Center in 1959. At that time, NASA research centers had a base program and there was no expectation that our research was to be applied. My goal at that time was to work on long term problems and solutions.

The current method in government research is to work on projects with a one or two year payoff. This is where our nation's corporations have gone in the last few years. Government is now following corporate America's lead in pursuing instant gratification rather than research which reaches over the horizon. It is now an MBA-driven culture, one which is anithetical to the long horizon stuff that inevitably leads to future breakthroughs.

I have had a wonderful career at NASA and I've been at the edge as I watched research from our laboratories change the world. But I am not pleased with the direction the agency is now pursuing, and I regret that a young physicist now beginning his or her career will not have the same opportunities I have had to dream, to explore their vision. This is to the detriment of NASA and to our nation.

The one big lesson I have learned in 43 years as a scientific researcher: the type of research we pursue is not as important as the horizon.

Philip Brockman
Distinguished Research Associate
NASA—Langley Research Center

  Science and the nation are inextricably intertwined. The economic and military strength of the county is based upon the technologies that have sprung from our basic science research. Likewise our medical system is fully dependent on a mixture of medical research and physical sciences detector development. Thus the health, well being, safety of our country's citizens depends very directly on the technological fruits of scientific research.

George F. Smoot

Dear President Bush,

Standard Long Term Analysis in Style of Business and Government

Science and the nation are inextricably intertwined. The economic and military strength of the county is based upon the technologies that have sprung from our basic science research. Likewise our medical system is fully dependent on a mixture of medical research and physical sciences detector development. Thus the health, well being, safety of our country's citizens depends very directly on the technological fruits of scientific research.

If the USA is to remain the premier nation on Earth, then it must maintain a robust scientific research program. The appropriate level is open to societal debate; however, many businesses, e.g. drug companies and advanced electronic companies, have developed guidelines at a few percent of their total budget. The issue is not can the country afford this level of expense, but whether it can afford not to continue an active, high-quality basic research program.

In terms of defense this is obvious. One only needs to ask the question: What would be the consequence if some other country to develop a new energy-directed or new generation bio-weapon, before the US did and created countermeasures? However, that same thing is true for major new technologies in the economic and health arenas? Basic scientific research is so key to the long-term viability of the nation, that even though the pay off is often years out, it is current priority. Change can be so rapid in technology that ten years is often two generations.

A strong scientific research program is not sufficient alone. Clearly, there must be sufficient infrastructure. The most key ingredient is a scientifically literate work force and general population. Just as it is clearly wise to invest in science, investment in education (science, mathematics, critical thinking) is better than exporting technical jobs, electronically or otherwise, to other countries (e.g. India, Russia, etc.) with stronger educational systems. No matter how good an infrastructure the nation has, it still must have the people to run it and the scientists and engineers to create and design the next generations. It is hard to believe that the country would hire foreign mercenaries for military and daily operations.

At present we enjoy a very good lifestyle. The primary question for the nation and civilization as a whole is: What is it that allows this? What has been the big change since the stone age? What steps can we take to keep this and progress to the next level? Are humans smarter, harder working, or any another way significantly better raw material now than in the stone age? One surmises most of the difference in physical attributes can be ascribed to better nutrition and medical care.

The Human Future for Stone-Age Man?

It appears in fact that most humans use our technological infrastructure to live a lifestyle with which a stone-age human could readily identify. People live in shelters—houses or apartments rather than caves. The go out daily to make their livelihood—now in SUVs, cars, commuter trains rather than most by foot. People gather by electronic fires (TV) or in bars ­most probably more isolated than the stone-age clans. In general the bulk of people live in, exploit, and make up a large cultural and technological infrastructure. They take advantage of the base accumulated by humanity.

Nearly all the advances are made by a very small fraction of the population—the innovators—mostly scientists, engineers, entrepreneurs. The society and nation, which encourages, nurtures, and makes this innovation possible and exploits it, will proper in many ways.

Humans as a whole really have not have changed basically since the stone age. Natural selection has not really changed humans since humans became the dominant species. In some regions local culture has instilled in its people respect for law and human life but even in those places the people will go to war when threatened. Other regions tribal and clan clashes are a way of life.

If the bulk of humans have not advanced physically, intellectually and socially over the stone age milieu, then new technology can be as easily used for terrorist and criminal activities as for neutral and beneficial activities. Thus as technology improves, the potential for devastating acts of terrorism continues to increase. The logical end would be when it is possible for a small group or single individual to destroy all life on Earth.

For economic, medical, and likely military motivations it is likely that many areas of technology will continue to develop and its potential for positive or negative consequences will increase. This means that, if humans are not changed significantly physically different, then we must understand how to develop a world culture that rejects suicide attacks and then eventually violence to resolve conflict. This would requires a whole program: (1) a better understanding of why people form cults and groups that support such activities, (2) understanding and removing the reservoir of young people (e.g. HAMAS recruits, Jim Jones cult,) (3) demagogic and totalitarian leaders and societies. This is a mixture of social and political science studies and actual programs.

The first step is to assess the various issues and determine what programs can be put in place in the short run and what research should begin soon. Then developing a longer-term program to reduce the threat of terrorism both by technical robustness and by social efforts. Note that El Al is most successful through focusing on the people rather than relying on sophisticated technology. Intelligence comes first and then attention to people. We would prefer not to be in the position of Israel as a country suffering terrorist activities on a very frequent and regular basis. It costs much in terms of casualties, economic, and military activities without any end in sight.

As long as terrorism can be kept at a low level in the country, then the USA can continue most of its development including the scientific research for the future. We also need to invest in the twin programs of being robust against terrorist acts and an active program to convert potential terrorists into positively contributing members of society. Rather than nation building we must engage in civilization building.

The path I did not mention was to stop or slow dramatically scientific research and the development of new technologies and hope or search for a new stability. We cannot stop things completely because other countries already have significant scientific and technological capability. Already third-rate countries, such as Iraq and North Korea, are able to have advanced welcome programs. We could enter new dark ages, the Nuclear Dark Ages or Weapons of Mass Destruction Dark Ages. I don't mean nuclear winter from the exchange of thousands of nuclear weapons; but a more gradual but catastrophe filled deterioration. In the new Dark Ages there will be a repeat of regional wars, blackmail and spoils of war, occasional small nuclear exchanges, all of these leading to a spiraling down of civilization.

George F. Smoot
Professor of Physics
University of California at Berkeley
Leader. NASA's COBE (Cosmic Background Explorer) Team
Author (with Keay Davidson) of Wrinkles In Time

  The typical college student who has studied Arabic for a year has essentially learned how to decode text and utter simple sentences—which is useless in decoding a memo written in running script by a terrorist, or even in understanding a speech by an Arab official.

John H. McWhorter

Dear President Bush:

Recent geopolitical events bring into sharp relief the inadequacy of foreign language training in the United States. I am dismayed by the inability of our high schools and universities to impart a truly useful competence in foreign languages to any but the most self-directed and dedicated of students.

Obviously, our country is in dire need of people proficient in Arabic, to assist us in defending ourselves against Islamicist terrorists. The shortage of such people in the FBI, CIA, and Foreign Service is truly chilling, as we see days go by before we even have worthy translations of Arabic-language statements and documents.

Yet not only are few institutions of learning equipped to impart Arabic to students, but even fewer are equipped to do so at anything beyond an elementary level that will serve little use in the urgent circumstances that confront us.

This is an especially serious problem with Arabic, a language that seems to present a virtual hydra-head of challenges. The script is elaborate, takes a great deal of practice to master, and only approximately spells out the sounds of words. The vocabulary is too different from English's to ease learning through ample cognates (opportunity/opportunidad in Spanish, milk/Milch in German). And on top of this, spoken Arabic varies from country to country to the point that Egyptians, for example, speak essentially a different language from Moroccans, and all of the spoken varieties are almost as different from the written one as French and Spanish are from Latin. The typical college student who has studied Arabic for a year has essentially learned how to decode text and utter simple sentences—which is useless in decoding a memo written in running script by a terrorist, or even in understanding a speech by an Arab official.

Military institutions, and other bodies with a concrete reason for teaching their charges foreign languages well, such as religious bodies, have long used truly effective, intense language-learning programs that produce competent foreign language speakers. It is also clear that European countries regularly give their students a solid grounding in English that has always been the envy of Americans. For years, I have been amazed at how an obscure series of books published by the Assimil company in Europe can give the solitary learner a decent conversational competence in any language in just six months of home study, so cleverly are the lessons arranged to impart what is really needed to speak the language in real life.

But meanwhile, school textbooks, for all their claims to teach "the language as it is really spoken", continue in a tradition of foreign language teaching descended from conceptions of grammar based on how Latin happens to be constructed, imparting tiny vocabularies ("my uncle is a lawyer but my aunt has a spoon") and rarely lending the learner any genuine sense of the "feel" of how native speakers actually put living sentences together. Language training rarely affords the student any serious time speaking the language at length on meaningful subjects. It is common to come away from several years of classes in, say, French or Spanish unable to even carry on a simple conversation with a native. Language training that leaves the student unable to say "This smells like a rose", "Never mind", "The car is stuck in the mud" or "Take your feet off the table"—sentences that eight years of dedicated French "teaching" left me unable to render—does not deserve the name.

The time has passed when our country could afford for excellent language teaching to be limited to circumstances lending specialized training to a few. Language teaching schools like Berlitz, the military, and even findings from academic specialists in second-language teaching have long bypassed our schools and universities in foreign language teaching. In our moment, it is high time that an effort on a nationwide scale be made to not only impart foreign languages to students, but to do it in an effective way.

And in these times, our efforts must be focused as much on languages like Chinese, Arabic, and Persian as the "old standby" languages like French, Spanish and German. Our geopolitical situation requires this, and the marvelous ethnic mixture of our country since the Immigration Act of 1965 renders it even more urgent, in helping to foster understanding and exchange in a new kind of America.


John H. McWhorter
Associate Professor of Linguistics, UC Berkeley
Senior Fellow, Manhattan Institute
Author of Losing The Race: Self-Sabotage In Black America and
The Power Of Babel: A Natural History Of Language.

 Advocate technology as a learning partner across the curriculum. This strategy is important for improving learning, developing computer literacy, and for inviting a variety of users, including girls, into technology.

Sherry Turkle

The Gender Gap In The Computer Culture

There has been much interest in the digital divide as it pertains to inequities between the poor and the rich. There is another digital divide that threatens to limit scientific productivity and scope. This is the inequity in the numbers of women who participate in the computer culture. The computer culture is still, in the main, made by engineers for engineers and by men for men. Girls are less likely to take high-level computing classes in high school, and comprised just 17 percent of those taking Advanced Placement Computer Science exams. Girls outnumbered boys only in their enrollment in "word processing" classes, arguably the contemporary version of a typing class. In 1995, at the post-secondary level, women received one in four of the Computer/Information Sciences bachelor's degrees and only 11 percent of the Ph.D.'s in Engineering-related technologies. These educational gaps reverberate in the workplace, where by most estimates women today occupy only 20 percent of the jobs in Information Technology.

A recent study of middle school and high school girls, commissioned by the American Association of University Women made it clear that gender inequity in digital culture is increasing. One goal is to get more girls into the "pipeline" to computer-related careers. This could, of course, be an end in itself, but diversity in participation would also mean a richer digital culture. Digital culture (not so far away from a world that asked users if they wanted to "abort, terminate, or fail" processes running on their machines) could be positively transformed through the integration of girls' and women's insights and life experiences. So one of the values in getting more girls and women interested in the computer pipeline is that their greater presence may transform the computer culture overall; by the same token, changes in the e-culture itself—the ways technology is discussed, valued, and applied—would invite more girls and women to participate fully in that culture, to become computer fluent.

This comment on values reflects the fact that today women seem to be disenfranchised in the computer culture for cultural rather than intellectual reasons. When young women are asked about their attitudes towards computing they almost never report overt discrimination, but at the same time, when asked to describe a person who is "really good with computers" they describe a man. And most of them do not predict that they will want to learn more about or become more involved with computers in the future. These girls are not computer phobic, they are "computer reticent." They say that they are not afraid but simply do not want to get involved. They express a "we can, but I don't want to" philosophy. Girls' views of computer careers, and of the computer culture—including software, games, and Internet environments—tend to reproduce stereotypes about a "computer person" as male and antisocial, Women no longer (as they once did) see computing as "too hard" for them. Earlier generations of women said, Women can't be involved in technical professions, "We can't but I want to." Girls and young women today seem to be saying, Women can do computing, "We can, but I don't want to!" This position is usually accompanied by a characterization of the computer as it has been presented to them at school as infused with values that they cannot identify with. Simply put: the computer culture is presented as a world which emphasizes technical capacity, speed, and efficiency. It estranges a broad array of learners, many girls included, who do not identify with the wizardry of computer aficionados and have little interest in the purely technical aspects of the machines. The computer culture has become linked to a characteristically masculine worldview, such that women too often feel they need to choose between the cultural associations of "femininity" and those of "computers," a cliché that has proven resistant to the growing diversity of information technology and its users. Girls discuss information technology-related careers not as too difficult, but as a "waste of intelligence." Insists a young woman from Baltimore, "Guys just like to do that: sit in a cubicle all day." In talking about their lack of desire to continue learning about computers, girls also focus on the violence and cruelty of current video games and see a culture that they do not want to participate in. They are happy to play social simulation games and chat with their friends, but see their identity on the computer as that of "users," not the empowered.

Their teachers have given them little to inspire them. Teacher education has stressed the "technical" side of things: Education schools tend to give instruction in basic technical skills rather than on how to integrate computers into the curriculum. A 1999 national survey found that only 29 percent of teachers had six or more hours of curriculum-integration instruction, whereas 42 percent had that amount of basic-skills training. In the study by the American Association of University Women of 2000, only 30% of teachers ranked as "sophisticated" in their use of computers report that they received any technology training in an undergraduate or master's teacher education program, which probably reflects in part responses from older teachers. Only 11 percent of the total teachers who were polled report that they received training specifically in how to apply or integrate computer technology into their lesson plans. Thus, current teacher-training practices emphasize short technical courses on connectivity and hardware. Preservice teachers make it clear that they start their jobs uninformed about what the technology is supposed to accomplish for their classrooms, either educationally or socially.

Our current approach to teacher training focuses on the technical properties of hardware; it does not emphasize educational applications or innovative uses of computing across the curriculum. Yet what teachers need is sustained and ongoing education about how to integrate technology with curricular materials and information about how to make technology part of a humanistic classroom culture, so essential for bringing girls into the picture. This latter approach would create better informed teachers as well as multiple entry points to computer competence for both students and teachers. The prevailing emphasis on the "mechanics of computer operation" does not respond to this need. As one teacher put it: "Without teacher education, it won't matter if each student has his/her own computer. We teachers hate having thousands of dollars of equipment thrown at us and being told to use it when we have no clue how to go about it"

There are many points of entry to address this problem. All require research and educational imagination in curriculum planning. All would make the computer culture more vibrant and relevant for women as well as men, and ultimately for us all.

• Advocate technology as a learning partner across the curriculum. This strategy is important for improving learning, developing computer literacy, and for inviting a variety of users, including girls, into technology. The infusion of technology across the curriculum also recognizes and supports multiple entry points into technology. Some learners may develop a fluency with information technology through music, some through mathematics, and others through the arts.

• Enforce a distinction between using the computer as a tool (teaching students how to use powerpoint) and using computation to inspire new ways of thinking and learning. It is the second that will inspire young minds to believe that there are rich rewards in staying with the subject.

• Professional development for teachers, both preservice and inservice, needs to emphasize not simply how computer technology works but on how it can spark creativity across disciplines. There appear to be a group of learners, predominantly young men, who are willing to throw themselves into computing, presented as a technical puzzle. But given the integration of computing into culture, those in the field need to have broader interests and motivation for being there. Improving the way computation is introduced in education will thus not only draw in young women and keep them from dropping out, it holds our only chance of having a more broadly based computer culture for all of us.

Sherry Turkle
Director, Initiative on Technology and Self
Author of Life on the Screen: Identity in the Age of the Internet and The Second Self: Computers and the Human Spirit.

 Rather than fixate on controlling greenhouse gases, which are politically hard to suppress, I suggest a new, innovative research program directed at the central global problem: warming. A partial cure can come from simple methods, until now little studied.

Gregory Benford

Mr President:

Prudence alone should lead you to ask the scientific establishment to study new, less costly methods of dealing with a global problem—the possibility of climate change. It is time to require more inventive thinking on this issue.

In his recent letter to you, William Calvin pointed out that shifting ocean currents could trigger big shifts in weather. Rather than fixate on controlling greenhouse gases, which are politically hard to suppress, I suggest a new, innovative research program directed at the central global problem: warming. A partial cure can come from simple methods, until now little studied.

They are:

1) Increase the overall reflection of sunlight from the planet as a whole. Here simple methods may work well. Trigger more cloud cover over the tropical oceans. Color rooftops and blacktop roads lighter, to lessen absorption. These ideas are fairly simple, and some field work on them has been done. They do need study to make them efficient and effective.

2) Hide carbon in the deep oceans. This keeps it from making carbon dioxide in the atmosphere for about 1000 years. Most biospheric carbon is already in the oceans anyway, and they can take a good deal more.

3) Push innovative energy research. Hand Ray Orbach at DOE the paper by Hoffert et al, in Science 298, (p 981, 2002) and ask him to implement its suggestions. You should also probably help develop nuclear power in the most needy areas of the developing nations. With safeguards against nuclear proliferation, this could cut down on the default choice many are using—coal burning plants.

These approaches need further research, and should be fashioned into off-the-shelf technologies. If in the next decade alarm bells go off, warning of an approaching big wrench in our global climate, we can then reach for these methods. Whatever one's position on global warming, it is prudent to be prepared with a strategy that goes beyond just nay-saying to the Kyoto Protocols.

Gregory Benford
Professor of Physics at University of California, Irvine
Author of Deep Time

 The problem of political and religious fanaticism is beyond the scope separately of psychology, political science, or historical study. An interdisciplinary program building upon current efforts but addressing the issues with the use of multiple methods is needed.

Vera John-Steiner

For a while after the defeat of Fascism and Nazism in the Second World War, there was a hope for an era of enlightenment. It was thought that a scientific understanding of its sources could help avoid a repetition of the fascist nightmare. The Authoritarian Personality by Theodor Adorno and co authors was a well known effort to achieve such understanding.

Today political and religious fanaticisms are a source of world wide anxiety. Al Qaeda is the most frightening at present. But it is not only Islamic fanaticism that leads to atrocities. The Oklahoma City bombing, mass murders of Moslems by Hindu mobs in India, the assassination of Prime Minister Rabin in Israel and of Martin Luther King in Nashville were the work of non-Islamic fanatics.

The torture-murder of a young gay man in Wyoming, the bombing of abortion clinics, the torching of black churches and of Jewish synagogues, all were associated with fanatical beliefs and movements.

Legislative, military, and educational solutions are proposed and undertaken, but without any prior understanding of how fanaticism is being fostered, both wittingly and unwittingly, or what causes certain fanatical individuals to resort to individual or mass murder. Neither is it well understood what factors or measures might counteract or inhibit fanatical violence. At present, specialists concerned with these issues focus either on social antecedents (including political, economic and religious factors) or on personality variables .
The problem of political and religious fanaticism is beyond the scope separately of psychology, political science, or historical study. An interdisciplinary program building upon current efforts but addressing the issues with the use of multiple methods is needed. Such a proposal is made while recognizing that no single approach, however carefully planned, can fully meet the challenge of fanaticism in contemporary society. But a major and well-planned study, devoted to causes and solutions, could make a contribution to the urgent task of decreasing fanatical violence. President Bush should initiate such a program as a scientific response to the sense of incomprehension and despair so prevalent in the world at present.

Vera John-Steiner
Presidential Professor, University of New Mexico
Author of Notebooks of the Mind and Creative Collaboration

Civilization's rocketing growth comes from exploiting non-renewables: coal since 1800 and oil since 1900, for example. US oil peaked about 15 years ago; global supplies should peak in about 10-15 years. There are semi-practical alternatives available or at least conceivable to let us get by on renewables, but virtually no one really sees the importance.

Paul B. MacCready

The world can support 1.5 to 2.0 billion people continuously, in combination with a natural world. Right now we have 6.2 billion people. The total mass of vertebrates on land and in the air is now made up 98% by humans+livestock+pets, and 2% by all natural creatures. Ten thousand years ago the 98% was only under 0.1%. Civilization's rocketing growth comes from exploiting non-renewables: coal since 1800 and oil since 1900, for example. US oil peaked about 15 years ago; global supplies should peak in about 10-15 years. There are semi-practical alternatives available or at least conceivable to let us get by on renewables, but virtually no one really sees the importance.

Virtually all your correspondents focus on details of how to make humans better and more numerous. Very few examine civilization's growth and the world as would a creature from space visiting us every few thousand years. Sincerely yours,

Paul B. MacCready
Chairman/Founder of AeroVironment Inc.
The "Father of Human-Powered Flight"

In a climate of growing religious fundamentalism and rising skepticism about science, the scientific community itself has began to understand the importance of reaching out to the wider public.

Margaret Wertheim

Dear Mr. President

Of all the scientific issues currently confronting us it seems to me that one is paramount—the woeful state of the public understanding of science in our nation. Some of your other correspondents have already raised this issue and I concur with much of what they have said. But I would like to bring to your attention a further dimension of the problem—the degree to which ignorance about science is correlated with gender, age, race and socioeconomic position.

At present the serious science readership in the USA is estimated to be around 1.5 million people, the combined subscriber base to our 2 major popular science publications, Discover and Scientific American. Readers of these and other science-based magazines are well served and scientifically fluent. But who precisely are these readers? Overwhelmingly they are white, male, over 35, well educated (often employed in science and technology fields) and in the upper socioeconomic brackets. This 1.5 million people constitutes just a little more than half a percent of our population, yet they are the audience at whom almost all scientific publishing is aimed. This is also the readers at whom science book publishers pitch their wares. The question I would like to raise is what about the other 99% of our population?

In a climate of growing religious fundamentalism and rising skepticism about science, the scientific community itself has began to understand the importance of reaching out to the wider public. Yet for all the admirable rhetoric on this subject, most science communication continues to be aimed at an already-well-informed audience. What I would like to propose, Mr President, is the establishment of a National Office for the Public Understanding of Science—an organization that would be charged with responsibility for reaching out to the "other 99", those who at present read almost no science and who, as polls continue to show, are almost universally ignorant about the subject. Such an office would have as its mission the task of finding and supporting truly innovative ways to communicate about science outside the box.

One major group of people who are disenfranchised from science are women. One of the tasks for our proposed National Office could be to explore ways in which science might be made more accessible and exciting to women. It is a sad but true fact that few women read science magazines, yet women buy and read an enormous number of magazines per se. One thing our office might explore then is ways to get science content into women's magazines such as Vogue, Elle and Glamour. What about science programs on television that might appeal to women? At present almost all the science on television is watched by men—is it possible that there are other ways of presenting science on TV that might also appeal to a female audience?

Another task our office might consider is ways in which scientific organizations could be partnered with cultural organizations such as art galleries and museums. So often science is presented as an isolated activity, but like all human enterprises science takes place within the context of the wider social and cultural spectrum. One way to draw more people into science, I believe, is to bring them through the portal of their other interests. There are, for example, many artists today producing work based around scientific themes—genetic engineering, nanotechnology, and computation in particular. This work, and the immense interest in the arts world in scientific issues right now, constitutes a formidable resource. Our office could work to create links between artists and scientists in specific areas of mutual interest.

We urgently need to improve our nation's pool of scientific literacy. If we are serious about achieving this goal we must be serious about reaching out to those who are disenfranchised. That means taking seriously who those people are and how to speak to them effectively. 99% of our people is too large an audience to ignore—it is no good sitting around demanding that they come to science—science must find ways to go out to them!

Margaret Wertheim
Science writer and Commentator
Author of Pythagoras' Trousers and The Pearly Gates of Cyberspace: A History of Space from Dante to the Internet.


The Engine of Prosperity
Academics Demand a New Science Policy from Bush

by Andrian Kreye
January 14, 2003

In the center of Cambridge at the intersection of Vassar and Main Street, you can still see the future growing. There the Massachusetts Institute of Technology is building an institute according to the plans of Frank Gehry. When you watch how the construction team translates powerful movements first drafted in lead and paper using concrete forms, steel girders, and sheets of aluminum, you get a sense of the euphoric mood that has reigned in the natural sciences in the last few decades.

But then came George W. Bush, September 11, and the crisis in Iraq. Everything now revolves around fear, war, and politics, and Gehry's new construction appears like an echo of a long gone era of progress and hope. Because the last decade brought forth not only scientific successes, but also a new scientific culture, the struggle for the future no longer takes place in privileged circles, but on the public stage.

The worldview with the greatest profile in this regard is the "third culture," because it attempts to find scientific answers to the most important questions facing humanity. New York literary agent John Brockman coined the term, represents most of the stars of this movement, and conducts its most important debating club on his internet platform, Edge (http://www.edge.org).

Every year since 1998, he has asked a public question just before the turn of the new year. This year, he drafted a fictitious e-mail from George W. Bush asking how the Edge community would respond to the president's question, "What are the most pressing scientific problems for the nation and the world, and what is your advice on how I can deal with them?"

The natural ambassadors

"Previously, countless articles in the scientific publications had complained," explains Brockman, "that the office of scientific advisor has become greatly weakened—with the consequence that as little as no public discourse about the sciences takes place under the current administration. Bush's science advisor, John Marburger, enjoys a spotless reputation, but the office for his ministry is located distant from the White House, and he has neither regular access to the president nor a public forum. That shows how much interest this government has in the sciences."

John Brockman has published 85 responses on his website to date. Nearly all of them contain sharp words for the president. "You are in an amazing position," reminds computer scientist Jaron Lanier. "You are the most powerful president in a generation. Be bold! Science and technology are the most potent tools mankind has for improving our circumstances." Chaos theoretician Doyne Farmer postulates, "Science is patriotic." One must only remember the origins of the nation. "Good old American know how is the foundation that has made this a great country. It is no coincidence that so many of the founding fathers, such as Thomas Jefferson and Benjamin Franklin, had a lifelong passion for science. Science is the engine that has fueled our prosperity."

In order to renew public excitement for the sciences, computer scientist David Gelernter of Yale University makes the resolute pitch, "Focus the nation's mind on a big, real and exciting problem. Ideally we ought to have a competitor to keep us playing our best game—but if the problem is interesting enough, maybe the competitor doesn't matter." The Australian physicist Paul Davies advises just the same: "Many commentators are urging George Bush Jr. to finish in Iraq what President George Bush Sr. began in the Gulf War. Mr. President, I urge you to apply this advise in space. Take up the challenge. Go to Mars! Even without a political challenge like Sputnik."

According to British evolutionary biologist Brian Goodwin, America stands before just such a dramatic challenge, one that far exceeds Iraq: "Accelerating the rate of CO2 increase in the atmosphere by profligate use of Iraq's vast oil supplies, together with the continuing deforestation of the Amazon, will not only turn the Amazon basin into a parched desert but plunge the entire mid-West into prolonged drought, resulting in famine in your own land." Behavioral researcher William Calvin blows the same tune: "When the patient is civilization itself, science can provide a heads-up—but only the best politicians have the talent to implement the foresight. And coming on stage now is a stunning example of how civilization must rescue itself."

Also according to Joel Garreau, a writer for the Washington Post, "We are entering an era of scientific change that is rocking no less than human nature itself." Above all, it is now worth capitalizing on the progress that genetic research has made. Physicist Freeman Dyson suggests calling into life a worldwide genome project to catalog the genetic structures of all species in the next 50 years.

Nobel Prize-winner and neurobiologist Eric Kandel believes on the contrary that one must above all research the biology that lies at the foundations of human consciousness. The Editor-in-Chief of Nature, Philip Campbell, sees completely different priorities — in light of the million people who die of malaria every year, he argues that we should be dedicating all of our powers to finding a vaccine. Against the background of the stem-cell debate futurologist Ray Kurzweil argues for the development of a technology with whose help a stem can be developed out of the DNA of every individual cell in order to evade the use of controversial embryonic cells while at the same time making overdue medical progress possible.

Kevin Kelly, his colleague from Wired magazine, warns of another danger: "Science, like business, has been totally captured by the next quarter mentality, and it will require a deliberate effort to stress the long view so that our knowledge matches our predicament." Only then do scientific utopias permit themselves to be pursued. And if one is to believe Munich brain researcher Ernst Pöppel, political utopia also follows closely on the heals of the scientific one. "Scientists are natural ambassadors." It is only scientists who bring people and nations together. "Independent of history, religious faith, economic status, gender or color of skin, scientists work together and have worked together to pursue a common goal, i.e. a deeper understanding of nature and culture."

[translation: Christopher Williams]

Copyright © sueddeutsche.de GmbH/Süddeutsche Zeitung GmbH

[Original German text]

John Brockman, Editor and Publisher
Russell Weinberger, Associate Publisher
contact: [email protected]
Copyright © 2003 by
Edge Foundation, Inc
All Rights Reserved.