Scientific American.com: How Things Work
Scientific American Topic - How Things Work
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Obama's choice for warrior in chief, Gen. James Mattis, calls Iraq invasion "the dumbest thing we ever did"
James N. Mattis is the four-star Marine general whom Barack Obama just nominated to head the U.S. Central Command, with oversight of the U.S. wars in Afghanistan and Iraq. If confirmed by the Senate (a hearing is set for today), Mattis will replace David Petraeus, who took over command of troops in Afghanistan from Stanley McChrystal after he and his staff spoke too bluntly to a Rolling Stone reporter.
The irony is that Mattis is a tough talker, too, who got in trouble in 2005 for saying that "it's fun to shoot some people." (Imagine that! A warrior who likes war !) I heard Mattis speak in May, just before his promotion, at the "Hybrid Warfare" conference that I described in a previous post . I'm not one to fawn over military leaders, but I liked Mattis. He came across as smart, earnest and reflective, if a bit scatterbrained. He sees himself as a just warrior, but he also seems to have an acute sense of war's inevitable moral ambiguities. "There is probably no one in this room more reluctant to go fight than me," he said. "But once in a fight, I give it everything I've got."
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Barack Obama - David Petraeus - United States - Afghanistan - War in Afghanistan
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How Does a Heat Wave Affect the Human Body?
Climate change promises to bring with it longer, hotter summers to many places on the planet. This June turned out to be the fourth-hottest month ever recorded--globally-- scientists are reporting . With more heat waves on the horizon, and a big one currently sweeping much of the U.S., the risk of heat-related health problems has also been on the rise. [More]
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Manipulation of the Crowd: How Trustworthy Are Online Ratings?
Web sites such as Amazon, TripAdvisor and Yelp have long depended on customers to rate books, hotels and restaurants. The philosophy behind this so-called crowdsourcing strategy holds that the truest and most accurate evaluations will come from aggregating the opinions of a large and diverse group of people. Yet a closer look reveals that the wisdom of crowds may neither be wise nor necessarily made by a crowd. Its judgments are inaccurate at best, fraudulent at worst.
According to Eric K. Clemons, a professor of operations and systems management at the Wharton School of the University of Pennsylvania, online ranking systems suffer from a number of inherent biases. The first is deceptively obvious: people who rate purchases have already made the purchase. Therefore, they are disposed to like the product. “I happen to love Larry Niven novels,” Clemons says. “So whenever Larry Niven has a novel out, I buy it. Other fans do, too, and so the initial reviews are very high--five stars.” The high ratings draw people who would never have considered a science-fiction novel. And if they hate it, their spite could lead to an overcorrection, with a spate of one-star ratings.
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How Babies Think (preview)
Thirty years ago most psychologists, philosophers and psychiatrists thought that babies and young children were irrational, egocentric and amoral. They believed children were locked in the concrete here and now--unable to understand cause and effect, imagine the experiences of other people, or appreciate the difference between reality and fantasy. People still often think of children as defective adults.
But in the past three decades scientists have discovered that even the youngest children know more than we would ever have thought possible. Moreover, studies suggest that children learn about the world in much the same way that scientists do--by conducting experiments, analyzing statistics, and forming intuitive theories of the physical, biological and psychological realms. Since about 2000, researchers have started to understand the underlying computational, evolutionary and neurological mechanisms that underpin these remarkable early abilities. These revolutionary findings not only change our ideas about babies, they give us a fresh perspective on human nature itself.
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How Does Sewage Treatment Work?
The guy running the snake down our sewer looks matter-of-fact. Our sewage has been backing up. Right next to the pipe connecting our house to the sewer line running down our street stands a 70-year-old willow oak, and I worry the tree's roots have found their way, during the droughty past year, into our line. He shrugs: Maybe it's tree roots, maybe it's a collapsed pipe, maybe it's a yo-yo. The snake went in only a dozen feet or so and found a clog, and now the little claw at the end is spinning. Once he pulls it out we'll know better what's going on. I leave him to his business, though I cast an annoyed glance at the oak. Sewer pipes fit together simply, with a bell joint, and tiny root hairs find their way to the nutrient-rich flow, then grow larger, eventually growing large enough to shatter the vitreous clay pipe that forms so many service lines or dislodge a joint if the pipes are cast iron. Nobody knows what our pipes, 70 years old, are made of, but I fear we're about to find out.
Fifteen minutes later he's winding the snake back up, writing a bill, and exonerating the oak.
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How did life begin on Earth?
LINDAU, Germany--What steps led to the origin of life on Earth? Scientists may be zeroing in on that most profound of questions. “We’ve gone a long way to showing” the processes that “set the stage” for cellular life on Earth, Jack Szostak said Tuesday here in his talk at the 60th annual Nobel Laureate Lectures at Lindau .
Recent findings--such as that life seems to be everywhere on Earth--have encouraged scientific inquiries into the nature of life’s beginnings, said Szostak. Along with Elizabeth H. Blackburn and Carol W. Greider, Szostak won the 2009 Nobel Prize in Physiology or Medicine for work in understanding telomeres [see Blackburn and Greider's Scientific American article “ Telomeres, Telomerase and Cancer ”]. His talk focused on his recent research on life’s start [see his Scientific American 2009 article, “ The Origin of Life on Earth ”]. He cited discoveries of microbes eking out existence in steaming hot springs in Yellowstone, in an acidic environment in Rio Tinto, Spain, and other hostile locations. “Even in rocks, there’s life,” he added, showing the audience an image of a green streak tenaciously spreading through rock. “Once life gets started, it can adapt and colonize many, many different environments.” In addition, astronomers have found hundreds of planets in other solar systems , and the space-based Kepler telescope recently identified more than 700 more candidate exoplanets. Many of those could have Earth-like conditions, raising the possibility that they also could harbor some form of life. How common might life be? “The question is: Is it easy or hard to make the transition in the chemistry of planets from not alive to alive?” asked Szostak.
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Adventures in Alaskan science: How I escaped from a thermokarst
Editor's Note: Vienna, Austria-based science writer Chelsea Wald is taking part in a two-week Marine Biological Laboratory journalism fellowship at Toolik Field Station , an environmental research post inside the Arctic circle. To see the current conditions in Toolik, check out the Webcam .
I was nearly eaten by a thermokarst. I just stepped in and, before I knew it, I was sucked in up to the top of my big rubber boot. [More]
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Wrangling Renewables and the Smart Grid: How Can the Federal Government Change the Future of Electricity?
Offshore wind turbines will line the Atlantic coast; vast solar arrays will cover swaths of the southwestern desert; transmission towers will cradle high-voltage direct current lines and take electricity from the windy Great Plains to the populated coasts. That is the renewable future for the U.S. that the Obama administration seems to envision and, certainly, what Jon Wellinghoff forecasts. And as chairman of the Federal Energy Regulatory Commission (FERC) Wellinghoff has a better than even chance of making his vision a reality.
Already, FERC is rewriting the rules for new transmission lines, potentially making it easier to permit new electricity-carrying capacity--and, as a result, unleashing the development of more renewable resources. The commission released a new rule on June 17 that would require that mandates for renewable energy--enacted in 36 states nationwide--be taken into account when determining where and when new transmission lines get installed.
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Making Connections (preview)
Many people wish their memory worked like a video recording. How handy would that be? Finding your car keys would simply be a matter of zipping back to the last time you had them and hitting “play.” You would never miss an appointment or forget to pay a bill. You would remember everyone’s birthday. You would ace every exam.
Or so you might think. In fact, a memory like that would snare mostly useless data and mix them willy-nilly with the information you really needed. It would not let you prioritize or create the links between events that give them meaning. For the very few people who have true photographic recall--eidetic memory, in the parlance of the field--it is more burden than blessing.
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The Green Apple: How Can Cities Adapt to Climate Change?
NEW YORK CITY--Here is how climate change could shut down a city: On the morning of August 8, 2007, a thunderstorm paralyzed the largest rail transit system in the U.S.--New York City's subway--during morning rush hour. Flash floods deposited more than 7,000 kilograms of dirt and debris on tracks that stretch more than 1,350 kilometers and carry 1.5 billion passengers annually. A December 1992 storm had a similar impact, including flooding portions of Lower Manhattan and the East River Drive. [More]
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How to find a habitable exoplanet: Don't look for one
Most planetary scientists will tell you that the objects they study are more complex and harder to categorize than almost anything else out there in the universe. That assertion is surprising and interesting, and it's a point that is gradually sinking in for astronomers. Much of the past 400 years of telescopic exploration has been about stellar taxonomy, pinning objects into their respective display cases. Despite the glorious wealth of 200 billion stars in our galaxy, the physics underlying their fundamental properties is remarkably uniform , and most can be readily described with only a few parameters--mass, age, elemental abundance. Individuals may be having particularly bad millennia, covered in spots, twisting their magnetic fields into knots, and throwing off flares, but their overall place in the cosmic zoo can be well defined.
Not true for planets, especially the smaller ones that just might be suitable for harboring life in a recognizable form. Mass, age and composition are just the start of a lengthy list of important characteristics. How far does it orbit from its parent star? What type of star does it orbit? Is the orbit elliptical ? Does the planet have an atmosphere, and if so what is the composition? Is there an axial tilt? Are there other planets in the system, exerting their gravitational might and forcing the orbit to shift over time? Are there gravitational tides at work, flexing and molding the planet? Is there volcanism or tectonic activity? How is the interior of a world layered? Is there a global magnetic field, cocooning the world? How did the planet assemble, does it have surface water? Did the planet get washed by rich organic chemistry in its youth? Does it have moons, and if so, what are the conditions on those? How often are they pelted by asteroids and comets?
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The Reproductive Revolution: How Women Are Changing the Planet's Future
Aisha, Miriam and Akhi are three young factory workers in Dhaka, the capital of Bangladesh. They are poorly educated and badly paid. But, like millions of other young women, they relish their freedom from the stultifying conformity of rural life, where women are at the constant beck and call of fathers, brothers and husbands.
There is something else. The three women together have 22 siblings. But Aisha plans three children, Miriam two and Akhi just one. They represent a gender revolution that many see as irrevocably tied to a reproductive revolution . Together, the changes are solving what once seemed the most difficult problem facing the future of humanity: growing population.
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Why so many artists have lazy eyes, and other things art can teach us about the brain
NEW YORK--When ancient denizens of central France painted leaping horses on the cave walls at Lascaux, they might not have had the late Renaissance understanding of how to illustrate perspective and three dimensions. But they did, with simple black lines, give the implication of depth, showing the far pair of limbs behind the closer pair. [More]
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Understanding the mind of the elite athlete
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