technology

Human ingenuity seldom fails to improve on the fruits of human invention. Whatever may have dazzled everyone on its debut is almost guaranteed to be superseded and, someday, to look quaint.

In 2000 B.C. a pair of ice skates made of polished animal bone and leather thongs was a transportation breakthrough. In 1610 Galileo's eight-power telescope was an astonishing tool of detection, capable of giving the senators of Venice a sneak peek at hostile ships before they could enter the lagoon. In 1887 the one-horsepower Benz Patent Motorwagen was the first commercially produced car powered by an internal combustion engine. In 1946 the thirty-ton, showroom-size ENIAC, with its 18,000 vacuum tubes and 6,000 manual switches, pioneered electronic computing. Today you can glide across roadways on in-line skates, gaze at images of faraway galaxies brought to you by the Hubble Space Telescope, cruise the autobahn in a 600-horsepower roadster, and carry your three-pound laptop to an outdoor cafe.

Of course, such advances don't just fall from the sky. Clever people think them up. Problem is, to turn a clever idea into reality, somebody has to write the check. And when market forces shift, those somebodies may lose interest and the checks may stop coming. If computer companies had stopped innovating in 1978, your desk might still sport a hundred-pound IBM 5110. If communications companies had stopped innovating in 1973, you might still be schlepping a two-pound, nine-inch-long cell phone. And if in 1968 the U.S. space industry had stopped developing bigger and better rockets to launch humans beyond the Moon, we'd never have surpassed the Saturn V rocket.

Oops!

Sorry about that. We haven't surpassed the Saturn V. The largest, most powerful rocket ever flown by anybody, ever, the thirty-six-story-tall Saturn V was the first and only rocket to launch people from Earth to someplace else in the universe. It enabled every Apollo mission to the Moon from 1969 through 1972, as well as the 1973 launch of Skylab 1, the first U.S. space station.

Inspired in part by the successes of the Saturn V and the momentum of the Apollo program, visionaries of the day foretold a future that never came to be: space habitats, Moon bases, and Mars colonies up and running by the 1990s. But funding for the Saturn V evaporated as the Moon missions wound down. Additional production runs were canceled, the manufacturers' specialized machine tools were destroyed, and skilled personnel had to find work on other projects. Today U.S. engineers can't even build a Saturn V clone.

What cultural forces froze the Saturn V rocket in time and space? What misconceptions led to the gap between expectation and reality?

Soothsaying tends to come in two flavors: doubt and delirium. It was doubt that led skeptics to declare that the atom would never be split, the sound barrier would never be broken, and people would never want or need computers in their homes. But in the case of the Saturn V rocket, it was delirium that misled futurists into assuming the Saturn V was an auspicious beginning—never considering that it could, instead, be an end.

On December 30, 1900, for its last Sunday paper of the nineteenth century, the Brooklyn Daily Eagle published a sixteen-page supplement headlined THINGS WILL BE SO DIFFERENT A HUNDRED YEARS HENCE. The contributors—business leaders, military men, pastors, politicians, and experts of every persuasion—imagined what housework, poverty, religion, sanitation, and war would be like in the year 2000. They enthused about the potential of electricity and the automobile. There was even a map of the world-to-be, showing an American Federation comprising most of the Western Hemisphere from the lands above the Arctic Circle down to the archipelago of Tierra del Fuego—plus sub-Saharan Africa, the southern half of Australia, and all of New Zealand.

Most of the writers portrayed an expansive future. But not George H. Daniels, a man of authority at the New York Central and Hudson River Railroad, who peered into his crystal ball and boneheadedly predicted:

It is scarcely possible that the twentieth century will witness improvements in transportation that will be as great as were those of the nineteenth century.

Elsewhere in his article, Daniels envisioned affordable global tourism and the diffusion of white bread to China and Japan. Yet he simply couldn't imagine what might replace steam as the power source for ground transportation, let alone a vehicle moving through the air. Even though he stood on the doorstep of the twentieth century, this manager of the world's biggest railroad system could not see beyond the automobile, the locomotive, and the steamship.

Three years later, almost to the day, Wilbur and Orville Wright made the first-ever series of powered, controlled, heavier-than-air flights. By 1957 the U.S.S.R. launched the first satellite into Earth orbit. And in 1969 two Americans became the first human beings to walk on the Moon.

Daniels is hardly the only person to have misread the technological future. Even experts who aren't totally deluded can have tunnel vision. On page 13 of the Eagle's Sunday supplement, the principal examiner at the U.S. Patent Office, W. W. Townsend, wrote, The automobile may be the vehicle of the decade, but the air ship is the conveyance of the century. Sounds visionary, until you read further. What he was talking about were blimps and zeppelins. Both Daniels and Townsend, otherwise well-informed citizens of a changing world, were clueless about what tomorrow's technology would bring.

Even the Wrights were guilty of doubt about the future of aviation. In 1901, discouraged by a summer's worth of unsuccessful tests with a glider, Wilbur told Orville it would take another fifty years for someone to fly. Nope: the birth of aviation was just two years away. On the windy, chilly morning of December 17, 1903, starting from a North Carolina sand dune called Kill Devil Hill, Orville was the first to fly the brothers' 600-pound plane through the air. His epochal journey lasted twelve seconds and covered 120 feet—a distance just shy of the wingspan of a Boeing 757.

Judging by what the mathematician, astronomer, and Royal Society gold medalist Simon Newcomb had published just two months earlier, the flights from Kill Devil Hill should never have taken place when they did:

Quite likely the twentieth century is destined to see the natural forces which will enable us to fly from continent to continent with a speed far exceeding that of the bird.

But when we inquire whether aerial flight is possible in the present state of our knowledge; whether, with such materials as we possess, a combination of steel, cloth and wire can be made which, moved by the power of electricity or steam, shall form a successful flying machine, the outlook may be altogether different.

Some representatives of informed public opinion went even further. The New York Times was steeped in doubt just one week before the Wright brothers went aloft in the original Wright Flyer. Writing on December 10, 1903—not about the Wrights but about their illustrious and publicly funded competitor, Samuel P. Langley, an astronomer, physicist, and chief administrator of the Smithsonian Institution—the Times declared:

We hope that Professor Langley will not put his substantial greatness as a scientist in further peril by continuing to waste his time, and the money involved, in further airship experiments. Life is short, and he is capable of services to humanity incomparably greater than can be expected to result from trying to fly.

You might think attitudes would have changed as soon as people from several countries had made their first flights. But no. Wilbur Wright wrote in 1909 that no flying machine would ever make the journey from New York to Paris. Richard Burdon Haldane, the British secretary of war, told Parliament in 1909 that even though the airplane might one day be capable of great things, from the war point of view, it is not so at present. Ferdinand Foch, a highly regarded French military strategist and the supreme commander of the Allied forces near the end of the First World War, opined in 1911 that airplanes were interesting toys but had no military value. Late that same year, near Tripoli, an Italian plane became the first to drop a bomb.

Early attitudes about flight beyond Earth's atmosphere followed a similar trajectory. True, plenty of philosophers, scientists, and sci-fi writers had thought long and hard about outer space. The sixteenth-century philosopher-friar Giordano Bruno proposed that intelligent beings in habited an infinitude of worlds. The seventeenth-century soldier-writer Savinien de Cyrano de Bergerac portrayed the Moon as a world with forests, violets, and people.

But those writings were fantasies, not blueprints for action. By the early twentieth century, electricity, telephones, automobiles, radios, airplanes, and countless other engineering marvels were all becoming basic features of modern life. So couldn't earthlings build machines capable of space travel? Many people who should have known better said it couldn't be done, even after the successful 1942 test launch of the world's first long-range ballistic missile: Germany's deadly V-2 rocket. Capable of punching through Earth's atmosphere, it was a crucial step toward reaching the Moon.

Richard van der Riet Woolley, the eleventh British Astronomer Royal, is the source of a particularly woolly remark. When he landed in London after a thirty-six-hour flight from Australia, some reporters asked him about space travel. It's utter bilge, he answered. That was in early 1956. In early 1957 Lee De Forest, a prolific American inventor who helped birth the age of electronics, declared, Man will never reach the moon, regardless of all future scientific advances. Remember what happened in late 1957? Not just one but two Soviet Sputniks entered Earth orbit. The space race had begun.

Whenever someone says an idea is bilge (which, I suppose, is British for baloney), you must first ask whether it violates any well-tested laws of physics. If so, the idea is likely to be bilge. If not, the only challenge is to find a clever engineer—and, of course, a committed source of funding.

The day the Soviet Union launched Sputnik 1, a chapter of science fiction became science fact, and the future became the present. All of a sudden, futurists went overboard with their enthusiasm. The delerium that technology would advance at lightning speed replaced the delusion that it would barely advance at all. Experts went from having much too little confidence in the pace of technology to having much too much. And the guiltiest people of all were the space enthusiasts.

Commentators became fond of twenty-year intervals, within which some previously inconceivable goal would supposedly be accomplished. On January 6, 1967, in a front-page story, The Wall Street Journal announced: The most ambitious U.S. space endeavor in the years ahead will be the campaign to land men on neighboring Mars. Most experts estimate the task can be accomplished by 1985. The very next month, in its debut issue, The Futurist magazine announced that according to long-range forecasts by the RAND Corporation, a pioneer think-tank, there was a 60 percent probability that a manned lunar base would exist by 1986. In The Book of Predictions, published in 1980, the rocket pioneer Robert C. Truax forecast that 50,000 people would be living and working in space by the year 2000. When that benchmark year arrived, people were indeed living and working in space. But the tally was not 50,000. It was three. The first crew of the International Space Station.

All those visionaries (and countless others) never really grasped the forces that drive technological progress. In Wilbur and Orville's day, you could tinker your way into major engineering advances. Their first airplane did not require a grant from the National Science Foundation: they funded it through their bicycle business. The brothers constructed the wings and fuselage themselves, with tools they already owned, and got their resourceful bicycle mechanic, Charles E. Taylor, to design and hand-build the engine. The operation was basically two guys and a garage.

Space exploration unfolds on an entirely different scale. The first moonwalkers were two guys, too—Neil Armstrong and Buzz Aldrin—but behind them loomed the force of a mandate from an assassinated president, 10,000 engineers, $100 billion, and a Saturn V rocket.

Notwithstanding the sanitized memories so many of us have of the Apollo era, Americans were not first on the Moon because we're explorers by nature or because our country is committed to the pursuit of knowledge. We got to the Moon first because the United States was out to beat the Soviet Union, to win the Cold War any way we could. John F. Kennedy made that clear when he complained to top NASA officials in November 1962:

I'm not that interested in space. I think it's good, I think we ought to know about it, we're ready to spend reasonable amounts of money. But we're talking about these fantastic expenditures which wreck our budget and all these other domestic programs and the only justification for it in my opinion to do it in this time or fashion is because we hope to beat them [the Soviet Union] and demonstrate that starting behind, as we did by a couple of years, by God, we passed them.

Like it or not, war (cold or hot) is the most powerful funding driver in the public arsenal. When a country wages war, money flows like floodwaters. Lofty goals—such as curiosity, discovery, exploration, and science—can get you money for modest-size projects, provided they resonate with the political and cultural views of the moment. But big, expensive activities are inherently long term, and require sustained investment that must survive economic fluctuations and changes in the political winds.

In all eras, across time and culture, only three drivers have fulfilled that funding requirement: war, greed, and the celebration of royal or religious power. The Great Wall of China; the pyramids of Egypt; the Gothic cathedrals of Europe; the U.S. interstate highway system; the voyages of Columbus and Cook—nearly every major undertaking owes its existence to one or more of those three drivers. Today, as the power of kings is supplanted by elected governments, and the power of religion is often expressed in non-architectural undertakings, that third driver has lost much of its sway, leaving war and greed to run the show. Sometimes those two drivers work hand in hand, as in the art of profiteering from the art of war. But war itself remains the ultimate and most compelling rationale.

Having been born the same week NASA was founded, I was eleven years old during the voyage of Apollo 11, and had already identified the universe as my life's passion. Unlike so many other people who watched Neil Armstrong's first steps on the Moon, I wasn't jubilant. I was simply relieved that someone was finally exploring another world. To me, Apollo 11 was clearly the beginning of an era.

But I, too, was delirious. The lunar landings continued for three and a half years. Then they stopped. The Apollo program became the end of an era, not the beginning. And as the Moon voyages receded in time and memory, they seemed ever more unreal in the history of human projects.

Unlike the first ice skates or the first airplane or the first desktop computer—artifacts that make us all chuckle when we see them today—the first rocket to the Moon, the 364-foot-tall Saturn V, elicits awe, even reverence. Three Saturn V relics lie in state at the Johnson Space Center in Texas, the Kennedy Space Center in Florida, and the U.S. Space and Rocket Center in Alabama. Streams of worshippers walk the length of each rocket. They touch the mighty rocket nozzles at the base, like the apes who touched the Monolith in the 1968 film 2001: A Space Oddysey, and wonder how something so large could ever have bested Earth's gravity. To transform their awe into chuckles, our country will have to resume the effort to boldly go where no man has gone before. Only then will the Saturn V look as quaint as every other invention that human ingenuity has paid the compliment of improving upon.

If you visit the gift shop at the Hayden Planetarium in New York City, you'll find all manner of space-related paraphernalia for sale. Familiar things are there—plastic models of the Space Shuttle and the International Space Station, cosmic refrigerator magnets, Fisher space pens. But unusual things are there too—dehydrated astronaut ice cream, astronomy Monopoly, Saturn-shaped salt-and-pepper shakers. And that's not to mention the weird things such as Hubble Telescope pencil erasers, Mars rock super-balls, and edible space worms. With hindsight, you'd expect a place like the planetarium to stock such stuff. But something much deeper is going on. The gift shop bears silent witness to the iconography of a half-century of American scientific discovery.

In the twentieth century, astronomers in the United States discovered galaxies, the expanding of the universe, the nature of supernovas, quasars, black holes, gamma ray bursts, the origin of the elements, the cosmic microwave background, and most of the known planets in orbit around solar systems other than our own. Although the Russians reached one or two places before us, we sent space probes to Mercury, Venus, Jupiter, Saturn, Uranus, and Neptune. American probes have also landed on Mars and on the asteroid Eros. American astronauts have walked on the Moon. And nowadays most Americans take all this for granted, which is practically a working definition of culture: something everyone does or knows about, but no longer actively notices.

While shopping at the supermarket, most Americans aren't surprised to find an entire aisle filled with sugar-loaded, ready-to-eat breakfast cereals. But foreigners notice this kind of thing immediately, just as traveling Americans immediately notice that supermarkets in Italy have vast selections of pasta, and that markets in China and Japan offer an astonishing variety of rice. The flip side of not noticing your own culture is one of the great pleasures of foreign travel: realizing what you hadn't noticed about your own country, and noticing what the people of other countries no longer realize about themselves.

Snobby people from other countries like to make fun of the U.S. for its abbreviated history and its uncouth culture, particularly compared with the millennial legacies of Europe, Africa, and Asia. But five hundred years from now historians will surely see the twentieth century as the American century—the one in which American discoveries in science and technology, rank high among the world's list of treasured achievements.

Obviously the U.S. has not always sat atop the ladder of science. And there's no guarantee or even likelihood that American preeminence will continue. As the capitals of science and technology move from one nation to another, rising in one era and falling in the next, each culture leaves its mark on the continual attempt of our species to understand the universe and our place in it. When historians write their accounts of such world events, the traces of a nation's presence on center stage sit prominently in the timeline of civilization.

Many factors influence how and why a nation will make its mark at a particular time in history. Strong leadership matters. So does access to resources. But something else must be present—something less tangible, but with the power to drive an entire nation to focus its emotional, cultural, and intellectual capital on creating islands of excellence in the world. Those who live in such times often take for granted what they have created, on the blind assumption that things will continue forever as they are, leaving their achievements susceptible to abandonment by the very culture that created it.

Beginning in the 700s and continuing for nearly 400 years—while Europe's Christian zealots were disemboweling heretics—the Abbasid caliphs created a thriving intellectual center of arts, sciences, and medicine for the Islamic world in the city of Bahgdad. Muslim astronomers and mathematicians built observatories, designed advanced timekeeping tools, and developed new methods of mathematical analysis and computation. They preserved the extant works of science from ancient Greece and elsewhere and translated them into Arabic. They collaborated with Christian and Jewish scholars. And Baghdad became a center of enlightenment. Arabic was, for a time, the lingua franca of science.

The influence of these early Islamic contributions to science remains to this day. For example, so widely distributed was the Arabic translation of Ptolemy's magnum opus on the geocentric universe, (originally written in Greek in a.d. 150), that even today, in all translations, the work is known by its Arabic title Almagest, or The Greatest.

The Iraqi mathematician and astronomer Muhammad ibn Musa al-Khwarizmi gave us the words algorithm, (from his name, al-Khwarizmi) and algebra (from the word al-jabr in the title of his book on algebraic calculation). And the world's shared system of numerals—0, 1, 2, 3, 4, 5, 6, 7, 8, 9—though Hindi in origin, were neither common nor widespread until Muslim mathematicians exploited them. The Muslims, furthermore made full and innovative use of the zero, which did not exist among Roman numerals or in any established numeric system. Today, with legitimate reason, the ten symbols are internationally referred to as Arabic numerals.

Portable, ornately etched, brass astrolabes were also developed by Muslims, from ancient prototypes, and became as much works of art as tools of astronomy. An astrolabe projects the domed heavens onto a flat surface and, with layers of rotating and non-rotating dials, resembles the busy, ornate face of a grandfather clock. It enabled astronomers, as well as others, to measure the positions of the Moon and the stars on the sky, from which they could deduce the time—a generally useful thing to do, especially when it's time to pray. The astrolabe was so popular and influential as a terrestrial connection to the cosmos that, to this day, nearly two-thirds of the brightest stars in the night sky retain their Arabic names.

The name typically translates into an anatomical part of the constellation being described. Famous ones on the list (along with their loose translations) include: Rigel (Al Rijl, foot) and Betelgeuse (Yad al Jauza, hand of the great one,—in modern times drawn as the armpit), the two brightest stars in the constellation Orion; Altair (At-Ta'ir, the flying one), the brightest star in the constellation Aquila, the eagle; and the variable star Algol (Al-Ghul, the ghoul), the second brightest star in the constellation Perseus, referring to the blinking eye of the bloody severed head of Medusa held aloft by Perseus. In the less-famous category are the two brightest stars of the constellation Libra, athough identified with the scorpion in the heyday of the astrolabe: Zubenelgenubi (Az-Zuban al-Janubi, southern claw) and Zebueneschamali (Az-Zuban ash-Shamali, northern claw), the longest surviving star names in the sky.

At no time since the eleventh century has the scientific influence of the Islamic world been equal to what it enjoyed the preceding four centuries. The late Pakistani physicist Abdus Salam, the first Muslim ever to win the Nobel Prize, lamented:

There is no question [that] of all civilizations on this planet, science is the weakest in the lands of Islam. The dangers of this weakness cannot be overemphasized since honorable survival of a society depends directly on strength in science and technology in the conditions of the present age.

Plenty of other nations have enjoyed periods of scientific fertility. Think of Great Britain, and the basis of Earth's system of longitude. The prime meridian is the line that separates geographic east from west on the globe. Defined as zero degrees longitude, it bisects the base of a telescope at an observatory in Greenwich, a London borough on the south bank of the River Thames. The line doesn't pass through New York City. Or Moscow. Or Beijing. Greenwich was chosen in 1884 by an international consortium of longitude mavens who met in Washington D.C. for that very purpose.

By the late nineteenth century, astronomers at the Royal Greenwich Observatory—founded in 1675 and based, of course, in Greenwich—had accumulated and catalogued a century's worth of data on the exact positions of thousands of stars. The Greenwich astronomers used a common, but specially designed telescope, constrained to move along the meridional arc that connects due north to due south through the observer's zenith. By not tracking the general east to west motion of the stars, they simply drift by as Earth rotates. Formally known as a transit instrument, such a telescope allows you to mark the exact time a star crosses your field of view. Why? A star's longitude on the sky is the time on a sidereal clock the moment the star crosses your meridian. Today we calibrate our watches with atomic clocks, but back then there was no timepiece more reliable than the rotating Earth itself. And there was no better record of the rotating Earth than the stars that passed slowly overhead. And nobody measured the positions of passing stars better than the astronomers at the Royal Greenwich Observatory.

During the seventeenth century Great Britain had lost many ships at sea due to the challenges of navigation that result from not knowing your longitude with precision. In an especially tragic disaster in 1707, the British fleet, under Vice Admiral Sir Clowdesley Shovell, ran aground into the Scilly Isles, west of Cornwall, losing four ships and two thousand men. Finally enough impetus for England to commissioned a Board of Longitude, which offered a fat cash award—£20,000—to the first person who could design an ocean-worthy chronometer. Such a timepiece was destined to be important in both military and commercial ventures. When synchronized with the time at Greenwich, such a chronometer could determine a ship's longitude with great precision. Just subtract your local time (readily obtained from the observed position of the Sun or stars) from the chronometer's time. The difference between the two is a direct measure of your longitude east or west of the prime meridian.

In 1735 the Board of Longitude's challenge was met by a portable, palm-sized clock designed and built by an English mechanic, John Harrison. Declared to be as valuable to the navigator as a live person standing watch at a ship's bow, Harrison's chronometer gave renewed meaning to the word watch.

Because of England's sustained support for achievements in astronomical and navigational measurements, the Royal Observatory at Greenwich landed the prime meridian. This decree fortuitously placed the international date line (180 degrees away from the prime meridian) in the middle of nowhere, on the other side of the globe in the Pacific Ocean. No country would be split into two days, leaving it beside itself on the calendar.

From the 1890s until the 1930s the Brits also made stunning advances in physics. Atoms are mostly empty space, with a small, dense nucleus packed with positively charged protons and neutral neutrons. Together, they are surrounded by negatively charged electrons. These particles are the principal components of atoms themselves. We take this fundamental knowledge for granted, as though it had been known forever. But using clever tabletop experiments, as well as early versions of particle accelerators, it was J. J. Thompson who discovered the electron in 1897, Ernest Rutherford who discovered the proton in 1914, and James Chadwick discovered the neutron in 1932.

Impressed it was all done in the same country? It all happened in the same building: the Cavendish Laboratory at the University of Cambridge. And it was data from these labs that forced a new generation of theorists to abandon classical concepts of physics in favor of the new branch of science known as quantum mechanics, a description of matter and energy that applies to nature on its smallest scales. To the world's community of physicists, the original Cavendish Laboratories are hallowed ground.

If the English have forever left their mark on particles and on the spatial coordinates of the globe, our basic temporal coordinate system—a solar-based calendar—is the product of an investment of science within the Roman Catholic Church. The incentive to do so was not driven by cosmic discovery itself but by the need to keep the date for Easter in the early spring. So important was this need, that Pope Gregory XIII established the Vatican Observatory, staffing it with erudite Jesuit priests who tracked and measured the passage of time with unprecedented accuracy. By decree, the date for Easter had been set to the first Sunday after the first full moon after the vernal equinox (preventing Holy Thursday, Good Friday and Easter Sunday from ever falling on a special day in somebody else's lunar-based calendar.) That rule works as long as the first day of spring stays in March, where it belongs. But the Julian calendar of Julius Caesar's Rome was sufficiently inaccurate that by the sixteenth century it had accumulated ten extra days, placing the first day of spring on April 1 instead of March 21. The four-year leap day, a principal feature of the Julian calendar, had slowly overcorrected the time, pushing Easter later and later in the year.

In 1584, when all the studies and analyses were complete, Pope Gregory deleted the ten offending days from the Julian calendar: the day after October 4 was declared to be October 15. The Church thenceforth made an adjustment: for every century year not evenly divisible by four-hundred, a leap day gets omitted that would otherwise have been counted, thus correcting for the overcorrecting leap day itself.

This new Gregorian Calendar was further refined in the twentieth century to become even more precise, preserving the accuracy of your wall calendar for tens of thousands of years to come. Nobody else had ever kept time with such precision. Enemy states of the Catholic Church (such as Protestant England, and its rebellious progeny, the American colonies) were slow to adopt the change, but eventually everyone in the civilized world, including cultures that traditionally relied on Moon-based calendars, adopted the Gregorian calendar as the standard for international business, commerce, and politics.

Ever since the birth of the Industrial Revolution the European contributions to science and technology have become so embedded in western culture that it may take a special effort to step outside and notice them at all. The Revolution was a breakthrough in our understanding of energy enabling engineers to dream up ways to convert it from one form to another. In the end, the Revolution would serve to replace human power with machine power, drastically enhancing the productivity of nations and the subsequent distribution of wealth around the world.

The language of energy is rich with the names of those scientists who contributed to the effort. James Watt, the Scottish engineer who perfected the steam engine in 1765, has the moniker best known outside the circles of engineering and science. Either his last name or his monogram gets stamped on the top of practically every light bulb. A bulb's wattage measures the rate it consumes energy, which correlates with its brightness. Watt worked on steam engines while at the University of Glasgow, which was, at the time, one of the world's most fertile centers for engineering innovation.

The English physicist Michael Faraday discovered electromagnetic induction in 1831, which enabled the first electric motor. The farad, a measure of a device's capacity to store electric charge, probably doesn't do full justice to his contributions to science.

The German physicist Heinrich Hertz discovered electromagnetic waves in 1888, which enabled communication via radio; his name survives as the unit of frequency along with its metric derivatives kilohertz, megahertz, and gigahertz.

From the Italian physicist Alessandro Volta we have the volt, a unit of electric potential. From the French physicist André-Marie Ampère, we have the unit of electric current known as the ampere, or amp for short. From the British physicist James Prescott Joule, we have the joule, a unit of energy. The list goes on and on.

With the exception of Benjamin Franklin and his tireless experiments with electricity, the U.S. as a nation watched this fertile chapter of human achievement from afar, preoccupied with gaining its independence from England and exploiting the economies of slave labor. Today the best we could do was pay homage in the original Star Trek television series: Scotland is the country of origin of the industrial revolution, and of the Chief Engineer of the star ship Enterprise. His name? Scotty of course.

In the late eighteenth century the Industrial Revolution was in full swing, but so too was the French Revolution. The French used the occasion to shake up more than the royalty; they also introduced the metric system to standardize what was then a world of mismatched measures—confounding science and commerce alike. Members of the French Academy of Sciences led the world in measures of the Earth's shape and had proudly determined it to be an oblate spheroid. Building on this knowledge, they defined the meter to be one ten-millionth the distance along the Earth's surface from the North Pole to the equator, passing through—where else?—Paris. This measure of length was standardized as the separation between two marks etched on a special bar of platinum alloyed with iridium. The French devised many other decimal standards that (except for decimal time and decimal angles) was ultimately adopted by all the civilized nations of the world except the U.S., the west African nation of Liberia, and the politically unstable, tropical nation of Myanmar. The original artifacts of this metric effort are preserved at the International Bureau of Weights and Measures—located, of course, near Paris.

Beginning in the late 1930s the U.S. became a nexus of activity in nuclear physics. Much of the intellectual capital grew out of the exodus of scientists from Nazi Germany. But the financial capital came from Washington, in the race to beat Hitler to build an atomic bomb. The coordinated effort to produce the bomb, was known as the Manhattan Project, so named because much of the early research had been done in Manhattan, at Columbia University's Pupin Laboratories.

The wartime investments had huge peacetime benefits for the community of nuclear physicists. From the 1930s through the 1980s, American accelerators were the largest and most productive in the world. These race-tracks of physics are windows into the funamental structure and behavior of matter. They create beams of subatomic particles, accelerate them to near the speed of light with a cleverly configured electric field, and smash them into other particles, busting them to smithereens. Sorting through the smithereens, physicists have found evidence for hoards of new particles and even new laws of physics.

American nuclear physics labs are duly famous. Even people who are physics-challenged will recognize the top names: Los Alamos; Lawrence Livermore; Brookhaven; Lawrence Berkeley, Fermi Labs; Oak Ridge. Physicists at these places discovered new particles, isolated new elements, informed a nascent theoretical model of particle physics, and collected Nobel Prizes for doing so.

The American footprint in that era of physics is forever inscribed at the upper end of the periodic table. Element number 95 is americium; number 97 is berkelium; number 98 is californium; number 103 is lawrencium, for Ernest O. Lawrence, the American physicist who invented the first particle accelerator; and number 106 is seaborgium, for Glenn T. Seaborg, the American physicist whose lab at the University of California, Berkeley, discovered ten new elements heavier than uranium.

Ever-larger accelerators reach ever higher energies, probing the fast receding boundary between what is known and unknown about the universe. The big bang theory of cosmology asserts that the universe was once a very small and very hot soup of energetic subatomic particles. With a superduper particle-smasher, physicists might be able to simulate the earliest moments of the cosmos. In the 1980s, when U.S. physicists proposed just such an accelerator (eventually dubbed the Superconducting Super Collider), Congress was ready to fund it. The U.S. Department of Energy was ready to oversee it. Plans were drawn up. Construction began. A circular tunnel fifty miles around (the size of Washington DC's beltway) was dug in Texas. Physicists were eager to peer across the next cosmic frontier. But in 1993, when cost overruns looked intractable, a fiscally frustrated Congress permanently withdrew funds for the $11 billion project. It probably never occurred to our elected representatives that by canceling the Super Collider they surrendered America's primacy in experimental particle physics.

If you want to see the next frontier, hop a plane to Europe, which seized the opportunity to build the world's largest particle accelerator and stake a claim of its own on the landscape of cosmic knowledge. Known as the Large Hadron Collider, the accelerator will be run by the European Center for Particle Physics (better known by an acronym that no longer fits its name, CERN). Although some U.S physicists are collaborators, America as a nation will watch the effort from afar, just as so many nations have done before.

Launching a spacecraft is now a routine feat of engineering. Attach the fuel tanks and rocket boosters, ignite the chemical fuels, and away it goes.

But today's spacecraft quickly run out of fuel. In fact, by the time a craft exits Earth orbit, there's no fuel left in its main tanks—which, no longer needed, have dropped back to Earth. Only tiny tanks remain, permitting only mild midcourse corrections. All the spacecraft can do is coast to its destination.

And what happens when it arrives?

Without the benefit of filling stations or sizable tanks of spare fuel, the craft cannot be made to slow down, stop, speed up, or make serious changes in direction. With its trajectory choreographed entirely by the gravity fields of the Sun, the planets, and their moons, the craft can only fly by its destination, like a fast-moving tour bus with no stops on its itinerary—and the riders can only glance at the passing scenery. That's what happened with the Pioneer and Voyager spacecraft in the 1970s and 1980s: they simply careened from one planet to the next on their way out of the solar system.

If a spacecraft can't slow down, it can't land anywhere without crashing, which is not a common objective of aerospace engineers. Lately, however, engineers have been getting clever about fuel-deprived craft. In the case of the Mars Rovers, their breakneck speed toward the Red Planet was slowed by aerobraking through the Martian atmosphere. That meant they could land with the help of nothing more than parachutes and airbags.

Today, the biggest challenge in aeronautics is to find a lightweight and efficient means of propulsion, whose punch per pound greatly exceeds that of conventional chemical fuels. With that challenge met, a spacecraft could leave the launchpad with fuel reserves onboard, and use them much later. Scientists could think more about celestial objects as places to visit than as planetary peep shows.

Fortunately, human ingenuity doesn't often take no for an answer. Legions of engineers are ready to propel us and our robotic surrogates into deep space with ion thrusters, solar sails, and nuclear reactors. The most efficient engines would tap energy from a nuclear reactor by bringing matter and antimatter into contact with each other, thereby converting all their mass into propulsion energy, just as Star Trek's antimatter engines did. Some physicists even dream of traveling faster than the speed of light, by somehow tunneling through warps in the fabric of space and time. Star Trek didn't miss that one either: the warp drives on the starship USS Enterprise were what enabled Captain Kirk and his crew to cross the galaxy during the TV commercials.

In October 1998, an eight-foot-tall, half-ton spacecraft called Deep Space 1 launched from Cape Canaveral, Florida. During its three-year mission, Deep Space 1 tested a dozen innovative technologies, including a propulsion system equipped with ion thrusters.

Acceleration can be gradual and prolonged, or it can come from a brief, spectacular blast. Only a major blast can propel a spacecraft off the ground. You've got to have at least as many pounds of thrust as the weight of the craft itself. Otherwise, the thing will just sit there on the pad. After that, if you're not in a big rush—and if you're sending cargo rather than crew to the distant reaches of the solar system—there's no need for spectacular acceleration. And that's when ion thrusters work best.

Ion-thruster engines do what conventional spacecraft engines do: they accelerate propellant (in this case, a gas) to very high speeds and channel it out a nozzle. In response, the engine, and thus the rest of the spacecraft, recoils in the opposite direction. You can do this science experiment yourself: While you're standing on a skateboard, let loose a CO₂ fire extinguisher (purchased, of course, for this purpose). The gas will go one way; you and the skateboard will go the other way. This equivalence of action and reaction is a law of the universe, first described by Isaac Newton in the late seventeenth century.

But ion thrusters and ordinary rocket engines part ways in their choice of propellant and their source of the energy that accelerates it. Deep Space 1 used electrically charged (ionized) xenon gas as its propellant, rather than the liquid hydrogen-oxygen combo burned in the space shuttle's main engines. Ionized gas is easier to manage than explosively flammable chemicals. Plus, xenon happens to be a noble gas, which means it won't corrode or otherwise interact chemically with anything. For 16,000 hours, using less than four ounces of propellant a day, Deep Space 1's foot-wide, drum-shaped engine accelerated xenon ions across an electric field to speeds of twenty-five miles per second and spewed them from its nozzle. As anticipated, the recoil per pound of fuel was ten times greater than that of conventional rocket engines.

In space, as on Earth, there is no such thing as a free lunch—not to mention a free launch. Something had to power those ion thrusters on Deep Space 1. Some investment of energy had to first ionize the xenon atoms and then accelerate them. That energy came from electricity, courtesy of the Sun.

For touring the inner solar system, where light from the Sun is strong, the spacecraft of tomorrow can use solar arrays—not for propulsion itself, but for the electric power needed to drive the equipment that manages the propulsion. Deep Space 1 has folding solar "wings." Fully extended, they span almost forty feet—about five times the height of the spacecraft itself. The arrays on them are a combination of 3,600 solar cells and more than 700 cylindrical lenses that focus sunlight on the cells. At peak power, their collective output was more than 2,000 watts, enough to operate only a hair dryer or two on Earth but plenty for powering the spacecraft's ion thrusters. And last I heard, the radio was still on.

Other, more familiar spacecraft—such as the now-disintegrated Soviet space station Mir and the nearly seven-year-old International Space Station (ISS)—have also depended on the Sun for the power to operate their electronics. A work-in-progress orbiting about 250 miles above Earth, the ISS will eventually carry more than an acre's worth of solar panels. For about a third of every ninety-minute orbit, as Earth eclipses the Sun, the station orbits in darkness. So by day, some of the collected solar energy gets channeled into storage batteries for later use during dark hours.

Although neither Deep Space 1 nor the ISS uses the Sun's rays to propel itself, direct solar propulsion is far from impossible. Consider Cosmos 1, an engineless, 220-pound spacecraft that will be propelled (once it achieves Earth orbit) solely by the pressure of sunlight. In fact, Cosmos 1 is a solar sail. By the time you read these words, it may have entered its initial intended orbit, 500 miles above Earth. The project is a privately funded collaboration between U.S. and Russian space scientists, led by The Planetary Society. This summer's launch will culminate nearly five years of work by rocket scientists who would rather collaborate than contribute to mutual assured destruction (aptly known as MAD).

Shaped like a supersize daisy, this celestial sailboat folds inside an unarmed intercontinental ballistic missile left over from the Soviet Union's cold war arsenal, and then launches from a Russian submarine. Cosmos 1 has a computer at its center and eight reflective, triangular sail blades made of Mylar reinforced with aluminum. When unfurled in space, each blade extends fifty feet yet is only 0.0002 inch thick—much thinner than a cheap trash bag—and can be individually angled to steer and sail the craft.

Once aloft, the solar sail will accelerate because of the continual, collective thrust of the Sun's gazillion photons, or particles of light, hitting its blades and bouncing off the reflective surfaces. As they bounce, the photons will give rise to a gazillion little recoils in the opposite direction. No fuel. No fuel tanks. No exhaust. No mess. You can't get greener than that.

Having entered space, a lightweight solar sail could, after a couple of years, accelerate to 100,000 miles an hour. Such a craft escapes from Earth orbit (where it was deposited by conventional rockets) not by aiming for a destination but by cleverly angling its blades, as does a sailor on a ship, so that it ascends to ever-larger orbits around Earth. Eventually its orbit could become the same as that of the Moon, or Mars, or something beyond.

Obviously a solar sail would not be the transportation of choice if you're in a hurry to receive supplies, but it would certainly be fuel efficient. If you wanted to use it as, say, a low-cost food-delivery van, you could load it up with freeze-dried veggies, ready-to-eat breakfast cereals, Cool Whip, and other edible items of extremely high shelf life. And as the craft sailed into sectors where the Sun's light is feeble, you could help it along with a laser, beamed from Earth, or with a network of lasers stationed across the solar system.

Speaking of regions where the Sun is dim, suppose you wanted to park a space station in the outer solar system—at Jupiter, for instance, where sunlight is only 1/27 as intense as it is here on Earth. If your Jovian space station required the same amount of solar power as the completed International Space Station will, your panels would have to cover twenty-seven acres. So you would now be laying solar arrays over an area bigger than twenty football fields. I don't think so.

To do complex science in deep space, to enable explorers (or settlers) to spend time there, to operate equipment on the surfaces of distant planets, you must draw energy from sources other than the Sun.

Since the early 1960s, space vehicles have commonly relied on the heat from radioactive plutonium as a power supply. Several of the Apollo missions to the Moon, Pioneer 10 and 11 (now more than 8 billion miles from Earth, and headed for interstellar space), Viking 1 and 2 (to Mars), Voyager 1 and 2 (also destined for interstellar space and, in the case of Voyager 1, farther along than the Pioneers), and Cassini (now orbiting Saturn), among others, have all used plutonium for their radioisotope thermoelectric generators, or RTGs. An RTG is an inefficient but long-lasting source of nuclear power. Much more efficient, and much more energetic, would be a nuclear reactor that could supply both power and propulsion.

Nuclear power in any form, of course, is anathema to some people. Good reasons for this view are not hard to find. Inadequately shielded plutonium and other radioactive elements pose great danger; uncontrolled nuclear chain reactions pose an even greater danger. And it's easy to draw up a list of proven and potential disasters: the radioactive debris spread across northern Canada in 1978 by the crash of the nuclear-powered Soviet satellite Cosmos 954; the partial meltdown in 1979 at the Three Mile Island nuclear power plant on the Susquehanna River near Harrisburg, Pennsylvania; the explosion at the Chernobyl nuclear power plant in 1986 in what is now Ukraine; the plutonium in old RTGs currently lying in (and occasionally stolen from) remote, decrepit lighthouses in northwestern Russia. The list is long. Citizens' organizations such as the Global Network Against Weapons and Nuclear Power in Space remember these and other similar events.

But so do the scientists and engineers who work on NASA's Project Prometheus.

Rather than deny the risks of nuclear devices, NASA has turned its attention to maximizing safeguards. In 2003 the agency charged Project Prometheus with developing a small nuclear reactor that could be safely launched and could power long and ambitious missions to the outer solar system. Such a reactor would provide onboard power and could drive an electric engine with ion thrusters—the same kind of propulsion tested in Deep Space 1.

To appreciate the advance of technology, consider the power output of the RTGs that drove the experiments on the Vikings and Voyagers. They supplied no more than a hundred watts, about what your desk lamp uses. The RTGs on Cassini do a bit better: they could power your thousand-watt microwave oven. The nuclear reactor that will emerge from Prometheus should yield as much as 200,000 watts of power, equivalent to the energy needs of a small school—or a single SUV. To exploit the Promethean advance, an ambitious scientific mission has been proposed: the Jupiter Icy Moons Orbiter, or JIMO. Its destinations would be Callisto, Ganymede, and Europa—three of the four moons of Jupiter discovered by Galileo in 1610. (The fourth, Io, is studded with volcanoes and is flaming hot.) The lure of the three frigid Galilean moons is that beneath their thick crust of ice may lie vast reservoirs of liquid water that harbor, or once harbored, life.

Endowed with ample onboard propulsion, JIMO would do a flyto, rather than a flyby, of Jupiter. It would pull into orbit and systematically visit one moon at a time, perhaps even deploying landers. Powered by ample onboard electricity, suites of scientific instruments would study the moons and send data back to Earth via high-speed, broadband channels. Besides efficiency, a big attraction would be safety, both structural and operational. The spacecraft would be launched with ordinary rockets, and its nuclear reactor would be launched cold—not until JIMO had reached escape velocity and was well out of Earth orbit would the reactor be turned on. As of this writing, however, plans for JIMO are on hold: a series of simpler missions will more expeditiously test the new Promethean propulsion systems.

Someday there might be wackier ways to explore within and beyond our solar system. The folks at NASA's now-defunct Breakthrough Propulsion Physics Project, for instance, were dreaming of how to couple gravity and electromagnetism, or tap the zero-point energy states of the quantum vacuum, or harness superluminal quantum phenomena. Their inspiration came from such tales as From the Earth to the Moon, by Jules Verne, and the adventures of Buck Rogers, Flash Gordon, and Star Trek. It's okay to think about this sort of thing from time to time. But, in my opinion, though it's possible not to have read enough science fiction in one's lifetime, it's also possible to have read too much of it.

My favorite science-fiction engine is the antimatter drive. It's 100 percent efficient: put a pound of antimatter together with a pound of matter, and they turn into a puff of pure energy, with no by-products. Antimatter is real. Credit the twentieth-century British physicist Paul A.M. Dirac for conceiving of it in 1928, and the American physicist Carl D. Anderson for discovering it five years later.

The science part of antimatter is fine. It's the science-fiction part that presents a small problem. How do you store the stuff? Behind whose spaceship cabin or under whose bunk bed would the canister of antimatter be kept? And what substance would the canister be made of? Antimatter and matter annihilate each other on contact, so keeping antimatter around requires portable matterless containers, such as magnetic fields shaped into magnetic bottles. Unlike the fringe propulsion ideas, where engineering chases the bleeding edge of physics, the antimatter problem is ordinary physics chasing the bleeding edge of engineering.

So the quest continues. Meanwhile, next time you're watching a movie in which a captured spy is being questioned, think about this: The questioners hardly ever ask about agricultural secrets or troop movements. With an eye to the future, they ask about the secret rocket formula, the transportation ticket to the final frontier.