Scientific American Magazine
Cover; July 1999; Scientific American Magazine; by Staff Editor; 1 Page(s)
Table of Contents; July 1999; Scientific American Magazine; by Staff Editor; 2 Page(s)
From the Editors, including Masthead; July 1999; Scientific American Magazine; by John Rennie; 1 Page(s)
Letters to the Editors; July 1999; Scientific American Magazine; by Staff Editor; 2 Page(s)
50, 100 and 150 Years Ago; July 1999; Scientific American Magazine; by Staff Editor; 1 Page(s)
STRESS AND SCHIZOPHRENIA-"The adrenal cortex seems to be involved in schizophrenia and perhaps in other mental conditions. A sample group of schizophrenic patients showed a striking inability to respond with enhanced steroid output to stress tests, despite the fact that their normal steroid secretion was little different from that of the general population. The adrenal cortex in the schizophrenic thus generally cannot change its activity with changing situations. It may be that chemical deficiencies of this kind, perhaps genetically determined, make some persons more vulnerable than others to the stresses of living."
LUNAR LANDSCAPE-"The most plausible explanation of the craters of the moon appears to be that they were created by the cataclysmic impacts of great meteorites. To draw a more definite conclusion about this hypothesis, we can draw on the knowledge accumulated during the recent war about craters blasted in the ground by bombs, mines and artillery shells. It becomes clear that the only type of crater that corresponds to the ones on the moon is the simple explosion pit formed by a single application of explosive power. Such a pit always has the same general form."
In Focus: Seeking Common Ground; July 1999; Scientific American Magazine; by Stix; 2 Page(s)
In the mid-1950s a group of astronomers funded by the National Science Foundation showed an interest in a mountain in southwest Arizona called Kitt Peak. Its clear, dry air, removed from Tucson's city lights, made it among the most promising sites being considered for the first national observatory. The Tohono O'Odham, however, refused a request to investigate the suitability of the site atop one of their most sacred mountains. An enterprising anthropologist at the University of Arizona suggested that the tribal council be invited to look through a telescope in the Steward Observatory on the university campus. Peering through the 36-inch-diameter (about one-meter-wide) telescope, the tribal elders had trouble containing their excitement. One after the other, each of the men would stare through the eyepiece and then move his head to view the bright moon glow through the top of the dome. Shortly thereafter, the tribal council voted to reverse itself and let the astronomers proceed. The members "were totally charmed by the people they called the men with long eyes," says Frank K. Edmondson, professor emeritus of astronomy at Indiana University, who chronicled a history of the project in his book on the U.S. national observatories.
Gone are the days when astronomers were granted free run of an isolated mountaintop for a mere peek through an eyepiece. Now astronomers who hope to peer deeper into the universe find themselves running into legal headaches on earth-which threaten to delay or scuttle massive projects.
Make Science, Not War; July 1999; Scientific American Magazine; by Musser; 1 Page(s)
To reach the observatory, we drove past the gutted motel, climbed over the fallen lamppost and walked past the trenches. Muhamed warned me to follow in his footsteps; the area hadn't been searched for mines yet. Over the stubs of trees we could see Sarajevo stretched out below us, a lovely sight for a gunner. The observatory was littered with shiny glass from shattered telescopes, an old Nature cover, a green plastic turtle Muhamed's daughter used to play with when visiting. "Some scraps of memory," he remarked. "I worked here 20 years."
Three years after the end of siege, Sarajevo is once again a fairly normal European city. But scientific research is still just a memory, and many people worry that it might always be. "Higher education never has been a priority in reconstruction efforts," says Wolfgang Benedek of the World University Service, an Austrian-based advocacy group.
Discerning Cern; July 1999; Scientific American Magazine; by Nemecek; 1 Page(s)
One might expect a trip to CERN, the European laboratory for particle physics, to include plenty of talk about quarks, bosons and the rest of the vanishingly small particles that make up our universe. Lately, though, discussions here have focused on much larger objects: the massive industrial cranes, backhoes and tunnel-boring machines being used to move around nearly one million tons of dirt with the goal of pushing back the frontiers of physics.
CERN, located on the French-Swiss border right outside Geneva, is currently home to the world's largest particle accelerator, the Large Electron Positron collider, or LEP. Since 1989 LEP has been creating fast-moving, highly energetic beams of electrons and their antimatter counterparts, positrons, and then smashing the two into each other; specially designed detectors monitor the energy and particles released during the collisions. The electron and positron beams pick up speed and energy as they travel around a circular tunnel 27 kilometers (17 miles) in circumference and 100 meters (330 feet) underground. Four detectors, each several stories tall, intersect the tunnel where the electron and positron beams collide.
By the Numbers: Christian Differences; July 1999; Scientific American Magazine; by Doyle; 1 Page(s)
So many Americans attend church, according to sociologists Roger Finke of Purdue University and Rodney Stark of the University of Washington, because there is a free market in religion, and a free market promotes competition among denominations for new members. U.S. churches, unlike the established churches of Europe, compete by making themselves more attractive to potential parishioners, and thus membership grows. Finke and Stark estimate that the number of adherents rose from 17 percent of the population in 1776 to about 60 percent today. In 1776 Congregationalists, Episcopalians and Presbyterians were among the leading denominations but lost position because they were ill equipped to compete for new members, particularly on the rapidly expanding frontier. Their well-paid, college-educated ministers were loath to leave comfortable parishes in the East for the rough-and-tumble of the frontier. Furthermore, their scholarly, sometimes dry sermons had little appeal to frontier settlers.
Soon the old-line denominations were eclipsed by the Methodists and the Baptists, who, with their revival meetings and circuit riders, promised life everlasting for the saved and hellfire for sinners. Moreover, their relatively uneducated ministers had a natural rapport with the people, coming as they did mostly from the same class. Methodists were the leading group in the mid-1800s, but as they became more affluent and as their ministers became seminary-trained, their fervor declined, and members who yearned for a more evangelistic faith left to found new churches.
Death Of A Vaccine?; July 1999; Scientific American Magazine; by Ezzell; 1 Page(s)
In the late 1980s AIDS researchers began to notice that some of their patients just weren't getting AIDS-despite the fact that they had been infected for roughly 10 years with the human immunodeficiency virus (HIV). The scientists started to hope that such "longterm nonprogressors," some of whom happened to have strains of HIV that were missing some genetic information, might hold the keys to developing an AIDS vaccine.
That hope has now been dampened. At least two long-term nonprogressors have now done just that-progressed toward AIDS. Besides being bad news for other people with HIV who do not yet have symptoms, this turn of events supports other evidence that an AIDS vaccine based on a live form of HIV that is missing one or more genes might not be safe enough to administer to humans.
In Brief; July 1999; Scientific American Magazine; by Staff Editors; 2 Page(s)
Mars Bars-Magnetic patterns in its now cold crust indicate that Mars once had enough heat to spin its iron core and generate a magnetic field, says the Mars Global Surveyor magnetometer team in the April 30 Science. The patterns also hint that Mars may have had processes similar to plate tectonics on Earth. Flip-flops in Earth's magnetic field imprint material along spreading ridges, where rising magma pools on either side and then cools. The magnetic reversals and spreading, caused by the motion of crustal plates, create a unique pattern on either side of the ridge. Such symmetry has yet to be seen on Mars, however, so its past tectonics may have been different.-Christina Reed
Multilegged Mayhem-At least one culprit has been identified behind some of the deformities seen recently in frogs in the U.S. Stanley K. Sessions and his colleagues at Hartwick College report in the April 30 Science that growth of extra legs can result directly from a trematode, rather than from the other suspects, pesticides that may mimic deformity-inducing retinoids. The minute trematodes, called Ribeiroia, burrow into the hind limb buds of tadpoles, wreaking havoc with leg growth. The crippled frogs may help their parasitic cargo infect its primary host-when the frogs fail to escape a hungry bird.-Jessa Netting
Anti Gravity: Soyuz Wanna
Fly in Space
there?s so little space.; July 1999; Scientific American Magazine; by Mirsky; 1 Page(s)
Anybody who goes anywhere without a roll of duct tape is a fool. This is common knowledge. It's also the second thing I thought of when I heard that a British businessman was angling for a ride on board the Mir space station, which at this point is barely even a mere space station. The first thing I thought of, as always, was my own name: Mirsky. My obsessive-compulsive desire to tack a suffix onto Mir skates through my head each time I see that three-letter word, a reaction that even I begin to find tiresome.
Anyway, the Russians, no longer Red, are in the red-which, after throwing off the shackles of communism, is like having an irony curtain descend on them. And Mir's keeping them there, with its operating costs of about $20 million a month. (In case you're wondering, $20 million converted to rubles equals one really stupid monetary transaction.) They were getting ready to scuttle Mir, skint as they are. But on January 22 they announced that they would keep Mir skyborne until 2002 if private investors would sponsor the station's upkeep.
Stem Cells Come Of Age; July 1999; Scientific American Magazine; by Beardsley; 2 Page(s)
A flurry of startling discoveries in stem cell biology in past months has shattered preconceptions about how cell specialization is controlled in the body and has boosted the field to the top of scientific, political and commercial agendas. The excitement has raised hopes that the long-sought goal of being able to regenerate human tissues may be closer than had been thought.
Stem cells can replicate indefinitely and can also give rise to more specialized tissue cells when exposed to appropriate chemical cues. Embryonic stem cells, which are derived from the earliest developmental stages of an embryo and can spawn almost all types of cells in the body, hit the headlines last November, when James A. Thomson of the University of Wisconsin described his isolation of human versions. John D. Gearhart of Johns Hopkins University published at about the same time a report that he had isolated similar human cells, called embryonic germ cells, from the developing gonads of fetuses; he is now making progress in turning the cells into specific tissue types. Since then, more remarkable results have been disclosed, particularly with more specialized stem cells. Such cells lack the complete developmental flexibility of embryonic stem cells but can still give rise to a useful variety of cells.
Profile: Pinker and the Brain; July 1999; Scientific American Magazine; by Hayashi; 2 Page(s)
Steven Pinker does not shy away from fights. Over the years, he has taken on feminists, romanticists, psychoanalysts and fellow linguists, including the brilliant Noam Chomsky. But perhaps his most noted clash has been with Stephen Jay Gould, the paleobiologist. The intellectual feud between the two men, which also involves other leading evolutionary theorists, eventually landed on the front page of the Boston Globe.
So it is with some sense of trepidation that I meet Pinker, the 44-yearold professor of psychology and director of the Massachusetts Institute of Technology's Center for Cognitive Neuroscience. Entering his home, a beautifully remodeled Victorian house a short walk from Harvard University, I am expecting a churlish gadfly. But I am immediately disarmed by his soft-spoken and affable manner.
Parsing Cells; July 1999; Scientific American Magazine; by Stix; 2 Page(s)
Biological cells are not genetic reductionists. The readouts from a gene-sequencing machine do not tell you much about the ultimate structure and function of the cellular proteins made by the genes. After a protein comes off the gene-to-amino-acid assembly line, it is altered as it assumes its place as a cog in the cellular machinery. Carbohydrates, phosphates, sulfates and other residues are pasted onto it. Enzymes may chop the amino acid chain into smaller pieces. A single gene may thus code for several different proteins.
A new biological subdiscipline called proteomics tries to circumvent the information gap between DNA and its end products. Proteomics envisions deducing the structure and interactions of all the proteins in a given cell. Comparing proteomic maps of healthy and diseased cells may allow researchers to understand changes in cell signaling and metabolic pathways better. And pharmaceutical companies might devise diagnostic tests and identify new drug targets.
Lots In Space; July 1999; Scientific American Magazine; by Scott; 3 Page(s)
Nothing shatters the serenity of the rain forest quite like a rocket launch. In French Guiana, local fishermen working their ancient profession in their equally ageold canoes off the coast of Kourou are jarred into the 20th century every three weeks as another Ariane 4 rocket blasts through the sky to hoist a satellite toward its appointed orbital rounds.
Tropical backwater though it may be, Kourou is now the global center for geosynchronous satellite launches. "For the moment we have more than 55 percent of the market of the world," says Jean-Yves Trebaol, Ariane range operations director. "Our hope for the future is to keep with this rate and have 30 percent of the market for constellations [of nongeosynchronous satellites]." Yet whether Arianespace can achieve that goal depends on whether its newest rocket proves to be reliable after only one successful test flight. Moreover, the competition is growing stronger in this literally volatile field, as other firms enter the launch business.
Practical Fractals; July 1999; Scientific American Magazine; by Musser; 1 Page(s)
Fractals have become one of the unifying principles of science, but apart from computer graphics, technological applications of these geometric forms have been slow in coming. Over the past decade, however, researchers have begun applying fractals to a notoriously tricky subject: antenna design.
Antennas seem simple enough, but the theory behind them, based on Maxwell's equations of electromagnetism, is almost impenetrable. As a result, antenna engineers are reduced to trial and error-mostly the latter. Even the highest-tech receivers often depend on a scraggly wire no better than what Guglielmo Marconi used in the first radio a century ago.
Holey Magic; July 1999; Scientific American Magazine; by Gibbs; 1 Page(s)
To less learned eyes, it might have seemed magical. Even physical chemist Thomas Ebbesen felt a "spooky" thrill when, 10 years ago, he raised a gold-plated glass microscope slide up to his eyes and saw not just his reflection in it but also the other side of the room through it. This was not the way that gold and light were supposed to behave.
Ebbesen, who was then working at NEC Research in Japan and is now affiliated with the company's laboratories in Princeton, N.J., did expect to see a little light coming through the gold film, because he had used an ion beam to riddle the metal layer with 100 million microscopic holes. But those holes were so minuscule-each just a few hundred nanometers in diameter, less than half the wavelength of visible light-that basic physics predicted that any view through them would be dim and indistinct. "Like frosted glass," says Tineke Thio, Ebbesen's collaborator at NEC.
Looking back at Apollo; July 1999; Scientific American Magazine; by Staff Editor; 6 Page(s)
On July 20, 1969, on a vast basaltic plain known as the Sea of Tranquillity, astronauts Neil A. Armstrong and Edwin "Buzz"Aldrin, Jr., became the first men to walk on the moon.Thirty years later scientists are still poring over the evidence gathered by Armstrong,Aldrin and the 10 Apollo astronauts who followed them to the lunar surface over the next three years.During the six successful manned missions to the moon, the dozen astronauts collected a total of 380 kilograms (838 pounds) of lunar rock. But just as impressive as the geologic samples was the photographic evidence: 32,000 still pictures,including thousands of shots taken by the astronauts with Hasselblad cameras mounted on the fronts of their space suits.
The film returned to Earth was so precious that technicians at the National Aeronautics and Space Administration duplicated the images just once before putting the film in cold storage.The master duplicates were then used to make copies for newspapers,magazines and museum exhibitions.Until recently,most of the Apollo pictures seen by the public were actually fourth- or fifth-generation copies,with little of the clarity of the original images. But in a new book entitled Full Moon (Alfred A. Knopf, 1999, $50), artist and photographer Michael Light presents a selection of 129 Apollo images that have been digitally scanned from the master duplicates.The sharp,striking photographs capture moments from nearly all the Apollo missions, showing every stage of the journey to the moon.
Cyber View; July 1999; Scientific American Magazine; by Grossman; 1 Page(s)
The past few years have seen a race on-line by higher education. The notion of reaching students who can't fit into the standard residential degree programs has gotten schools everywhere putting everything from individual courses to entire degree programs in cyberspace. The institutions include the traditional universities, such as the University of California at Los Angeles, and distance-learning specialists, such as the University of Phoenix, along with cyber start-ups such as the Western Governors University project and the California Virtual University. Plenty of opportunity exists in remote education: Britain's 30-year-old Open University, the worldwide pioneer in distance learning, had by 1998 awarded more than 200,000 bachelor's degrees since the school's inception in 1969. Management guru Peter F. Drucker has predicted the death of the traditional residential higher education within 30 years.
Now two reports released in April question whether on-line learning can do what's been claimed for it. The first, "The Virtual University and Educational Opportunity," was published by the College Board in Princeton, N.J., and warns that the Internet could become an engine of inequality. Poor kids, the report argues, are less likely to be familiar with the technology or have access to the equipment. Three quarters of households with incomes greater than $75,000 have computers, as opposed to one third with incomes between $25,000 and $35,000 and one sixth of those with incomes less than $15,000.
Life's Far-Flung Raw Materials; July 1999; Scientific American Magazine; by Bernstein, Sandford, Allamandola; 8 Page(s)
For centuries, comets have imprinted disaster on the human mind. By 400 B.C. Chinese astronomers had sketched 29 varieties of comets, many foretelling calamity. Aristotle's assumption that comets were a warning from the gods gripped Western civilization for two millennia after the heyday of the ancient Greeks. Even at the close of the 20th century, comets and meteors play starring roles in cinematic tales of doom and destruction. The comet threat, it turns out, is not merely mythological. Modern science has revealed that a giant collision probably did in the dinosaurs, and in 1994 human beings nervously watched Comet Shoemaker-Levy 9 smash into Jupiter.
In light of their ominous reputation, it is ironic to consider that such far-flung space debris might be responsible for making Earth the pleasant, life-covered planet it is today. Since the early 1960s, space scientists have speculated that comets and other remnants of solar system formation hauled in gas and water molecules and that these components provided the atmosphere and oceans that made the planet habitable. A growing number of investigators, including our team at the Astrochemistry Laboratory at the National Aeronautics and Space Administration Ames Research Center, now believe that some important raw materials needed to build life also hitched a ride from space. Some of these extraterrestrial organic molecules formed leaky capsules that could have housed the first cellular processes. Other molecules could have absorbed part of the sun's ultraviolet radiation, thereby sheltering less hardy molecules, and could have helped convert that light energy into chemical food.
Genetic Vaccines; July 1999; Scientific American Magazine; by Weiner, Kennedy; 8 Page(s)
Vaccines arguably constitute the greatest achievement of modern medicine. They have eradicated smallpox, pushed polio to the brink of extinction and spared countless people from typhus, tetanus, measles, hepatitis A, hepatitis B, rotavirus and other dangerous infections. Successful vaccines have yet to be introduced, however, for too many deadly or debilitating disorders-among them, malaria, AIDS, herpes and hepatitis C. This gap exists because standard immunization methods work poorly or pose unacceptable risks when targeted against certain illnesses.
Clearly, alternate strategies are needed. One of the most promising creates vaccines out of genetic material, either DNA or RNA. In the past 10 years such vaccines have progressed from a maligned idea to entities being studied intensively in academia and industry and in early human trials.
The Mystery of Nucleon Spin; July 1999; Scientific American Magazine; by Rith, Schäfer; 6 Page(s)
Protons and neutrons were among the first subatomic particles discovered this century. They reside in the nuclei of atoms and are hence known as nucleons; they make up more than 99.9 percent of the matter in the everyday world around us, including this page and you yourself. (The other 0. 1 percent is electrons.) Eighty years of experimental study and theoretical analysis have taught us much about the nucleons, yet certain of their fundamental properties still hold puzzles and surprises. For the past decade, physicists have labored to resolve a particular quandary known as the spin crisis.
This crisis emerged from the highly successful quark model of subatomic particles. Theorists developed this model as a neat, compact description of the myriad of new particles detected during the 1950s and 1960s, as well as of old familiars such as the proton and neutron. The properties and interactions of the particle zoo fell into patterns that could be explained by their being made of just three species of quark, called up, down and strange.
The Earliest Zoos and Gardens; July 1999; Scientific American Magazine; by Polinger Foster; 8 Page(s)
Few people realize that zoos and decorative gardens have an astonishingly long history. Some 5,000 years ago in the Middle East, writing was invented and the first cities were established. Within 700 years of those momentous events, Egyptian pharaohs had built their famous pyramids, Mesopotamian kings had created the world's first empires, and rulers in both lands had established menageries and botanical gardens.
Over the next two millennia, the zoos grew to include such animals as giraffes, cheetahs and monkeys from Africa, seals from the Mediterranean, and bears and elephants from Asia. The gardens often incorporated groves of rare trees, aviaries of exotic birds and a central pool stocked with unusual fish.
The Future Of Fuel Cells; July 1999; Scientific American Magazine; by Staff Editors; 2 Page(s)
In 1839 William R. Grove, a British physicist, demonstrated that the electrochemical union of hydrogen and oxygen generates electricity. Fuel cells based on this concept, however, remained little more than laboratory curiosities for more than a century, until the 1960s, when the National Aeronautics and Space Administration began deploying lightweight-and expensive-versions of the devices as power sources for spacecraft. Today the technology, which promises clean, efficient and quiet operation, is being touted for a host of applications, including cellular phones, laptop computers, automobiles and home power supplies.
But numerous hurdles loom. For starters, there is the question of fuel source. Liquid hydrogen, an energy-rich substance, must be stored at impractically low temperatures just above absolute zero. Methanol, a liquid at room temperature, contains abundant hydrogen, but extracting it usually entails reformation, a cumbersome chemical conversion. Furthermore, pricey platinum catalysts are often required. These and other factors complicate the basic design of fuel cells, often necessitating the addition of elaborate subsystems.
Engine for Vehicles; July 1999; Scientific American Magazine; by Appleby; 6 Page(s)
As the number of cars, trucks and buses on the road increases, the need for alternatives to the internal-combustion engine becomes ever more apparent. The largest of the world's oil reserves are in the politically unstable Middle East and in any event cannot last indefinitely. The health hazards posed by nitrogen oxides and other compounds in vehicle exhausts are well known, and concerns about emissions of the greenhouse gas carbon dioxide are also growing. Although cars are becoming cleaner and more efficient, the gains are being offset by the rapid growth in the total number of vehicles, especially in Asian markets. In 1996 some 634 million vehicles were on the road worldwide, an increase of almost 30 percent from the figure a decade earlier; collectively, they emitted some 3.7 billion tons of carbon dioxide, according to the International Energy Agency.
Automakers are investigating a variety of ways to reduce emissions drastically. Electrochemical fuel cells producing power for electric drive motors are now widely seen as a promising possibility. Unlike familiar dry cell batteries, which store a fixed amount of energy in their electrodes, fuel cells can run as long as fuel and oxidant are supplied-or at least until components in the cells degrade.
The Power Plant in Your Basement; July 1999; Scientific American Magazine; by Lloyd; 6 Page(s)
As deregulation of the electric utility industry dissolves the monopoly once held by most power generators, one repercussion has been increasingly long distances between some buyers and sellers of electricity. Nevertheless, within a decade or two, some customers may find themselves living in a home whose electricity comes not from a generating plant tens, hundreds or even thousands of kilometers away but rather from a refrigerator-size power station right in their own basements or backyards. Moreover, not just homes but shops, small businesses, hotels, apartment buildings and possibly factories may all be powered in the same way: by fuel cells in the range of five to 500 kilowatts.
Companies and industrial research laboratories in Belgium, Canada, Denmark, Germany, Italy, Japan, Korea and the U.S. have aggressive fuel-cell development efforts under way, and at least a few are already selling the units. In fact, a subsidiary of United Technologies has been offering fuel cells of up to 200 kilowatts for almost a decade. They have sold about 170 units, many of which are used for generation of both heat and power at industrial facilities or for backup power. They are also increasingly being used at wastewater treatment plants and in "green" facilities, which showcase environmentally sensitive technologies and design.
Replacing the Battery
in Portable Electronics; July 1999; Scientific American Magazine; by Dyer; 6 Page(s)
Despite major advances in portable electronics, the battery has changed little. Even so, small batteries remain the only choice for consumer products that need up to about 20 watts of power, for everything from toys to laptop computers. But batteries can be heavy and expensive, and they can expire without warning, requiring either replacement (presenting a disposal problem) or recharging (taking hours of precious time). Is there no better alternative?
Ironically, the answer may lie with another invention from the past century: fuel cells. Theoretically, the technology has the same consumerfriendliness as batteries: quiet and clean conversion of a material's chemical energy into electricity. But the real advantage of fuel cells lies in their amazing ability to liberate electrical energy from the hydrogen atom. A fuel cell running on methanol could provide power for up to 20 times longer than traditional nickel-cadmium batteries in a comparably sized package but at a lower price and for a small fraction of the weight. Another benefit is that fuel cells do not require lengthy recharging; they can instead be replenished quickly, simply by adding more fuel.
The Amateur Scientist; July 1999; Scientific American Magazine; by Carlson; 2 Page(s)
If electric fields were visible, then even the most barren spot on the earth would provide an awesome sight. Standing on a hilltop, you would see a forest of electric-field lines shooting out of the ground everywhere, stretching up to the ionosphere. You could watch them sweep across the horizon to gather under storms. In fact, the earth's electric field is far more dynamic-and, for me, more interesting-than its magnetic counterpart.
This electrical phenomenon is generated by the thousands of thunderstorms that pummel our planet continuously with 100 lightning bolts a second and that also deliver to the ground a tremendous amount of charge on raindrops [see The Amateur Scientist, August 1997]. As a result, we live atop an ocean of negative charge that generates an electric field of approximately 100 volts per meter elevation. In other words, when you are standing, your head is about 200 volts greater than your feet. And when a thunderstorm passes overhead, the electric fields can increase to thousands of volts per meter. Fortunately, there is very little free charge (unattached electrons and positive ions) in the air around us, and so these high voltages cannot create any large currents, which would otherwise surely electrocute us.
Mathematical Recreations; July 1999; Scientific American Magazine; by Stewart; 3 Page(s)
Mathematics and art have many points of contact, but none is more beautiful than the concept of symmetry. The mathematician's approach to symmetry is a little too rigid for most forms of visual art, but it can be readily applied to any art form that features repetitive patterns. Wallpaper, fabrics and tiles are familiar examples, and all of them can rise to great artistic heights. Tiles and wallpaper designed by 19th-century British artist William Morris are displayed in London's Victoria and Albert Museum. The Edo-Tokyo Museum possesses some absolutely outstanding examples of patterned kimonos, and the Alhambra palace in Granada, Spain, is renowned worldwide for its intricate tiled patterns.
Although the basic mathematics of symmetry and tilings was worked out long ago, new discoveries continue to be made, often by artists. Rosemary Grazebrook, a contemporary British artist, has invented a remarkably simple tiling system that is eminently practical and different enough from the usual rectangular tiles to be interesting. It is also ingenious and, in the right hands, beautiful.
Reviews; July 1999; Scientific American Magazine; by de Grasse Tyson, Staff Editors; 3 Page(s)
Imagine peering into a crystal ball and watching the laws of nature run their course through all of time and all of space. What exactly would you see? One thing is for sure, the cosmos is destined to expand forever. Regardless of what you may occasionally hear on the street or read in the newspapers, the idea that the universe will one day recollapse has never been supported by reliable data. We've made the observations. We've done the arithmetic. When you add up all the mass contained in the hundred billion galaxies scattered from here to the limits of our most powerful telescopes-the ubiquitous dark matter included-you do not have enough gravity to halt our current state of expansion. Worse yet, recent evidence that compared the observed brightness of distant supernovae with their predicted brightness suggests that the expansion of the universe may actually be accelerating.
This one-way cosmos in which we live may not be philosophically satisfying, but to Fred Adams and Greg Laughlin, co-authors of The Five Ages of the Universe, it's a theorist's amusement park. Armed with just the few basic laws of physics and an understanding of the astrophysical behavior of cosmic objects, the authors ride the universe into a formerly unimaginable future. Making the necessary assumption that our knowledge of the laws of physics is accurate and complete, they ask a simple question of their crystal ball: What is the long-term evolutionary fate of all objects in our eternally expanding universe, from its subatomic particles to entire galaxies?
Wonders: The Hidden Cosmic Ruckus; July 1999; Scientific American Magazine; by Philip Morrison; 2 Page(s)
The sun and its planets share the universality of the building blocks of our quantum world: electrons, nucleons and photons. But it comes as a bit of a surprise that the solar system and distant planetary systems have another distinctive modular origin all their own. Those planetary "bricks" are not tiny identical particles; rather they are roughly built out of dust, rock, tarry organics and ice, somewhat like a Boston street gutter in winter. They were postulated around 1900 by two University of Chicago professors, geologist T. C. Chamberlain and astronomer F. R. Moulton. The fine old word "infinitesimal" had long expressed a vanishingly small quantity, so they coined "planetesimal"-the smallest object that might be thought of as an orbiting planet.
In abundance, such modules of matter-estimated to be about a mile in diameter-will attract, collide and merge to become progenitors of full-scale planets. As planetesimals grow ever more massive, their gravitational attraction to the sun and to one another becomes more effective than the collisions they encounter as they move in the solar nebula.
Connections: A Few Notes; July 1999; Scientific American Magazine; by James Burke; 2 Page(s)
One of the things I do to relax (it has the opposite effect on all within earshot) is to play the classical guitar badly, and the other day I warmed up by accompanying myself to a whistled rendition of "Yankee Doodle." Then, just as I was getting down to the serious matter of scales, before attempting yet another failed attack on "Recuerdos de la Alhambra," it flashed upon my inward eye that scales had been mathematically sorted out by that Dutch Renaissance whiz Simon Stevin. Pioneer of decimal fractions, military adviser to Count Maurice of Nassau and builder of sandyachts. And he who had divided the octave into the semitones I was now plucking.
In 1608 Stevin must have been out to lunch on the day an unknown local optical noodler named Hans Lippershey fetched up at Maurice's place with a new gizmo to help the count in his never-ending efforts to turn the Dutch army into a high-tech force with which to chuck out the occupying Spaniards (which he eventually did). Lippershey brought along a tube with a lens at each end to be used for "looking," as he put it. Maurice is reported to have muttered something about binoculars and sent him off with a flea in his ear. Next thing we hear, it's 1609, and Galileo's got the kit and built one. He is about to change the entire history of everything by revealing that the moon has mountains. And he will go on to prove that Earth isn't the center of the cosmos by showing moons orbiting some other body: the planet Jupiter.
Working Knowledge; July 1999; Scientific American Magazine; by Zambelli, Sr.; 1 Page(s)
Surely no other area of applied chemistry has given people so much wonder and enjoyment as fireworks have. Modern displays use computer-controlled electronic ignition and precisely timed fuses to synchronize the bursts to the pulse of music. But the spectacular explosions themselves result from the arrangement of powders, resins, gums, paper and string in clever (and often secret) ways that have changed remarkably little despite five centuries of pyrotechnical experimentation.