Another Inconvenient Truth: The World's Growing Population Poses a Malthusian Dilemma

By 2050, the world will host nine billion people --and that's if population growth slows in much of the developing world. Today, at least one billion people are chronically malnourished or starving. Simply to maintain that sad state of affairs would require the clearing (read: deforestation) of 900 million additional hectares of land, according to Pedro Sanchez, director of the Tropical Agriculture and Rural Environment Program at The Earth Institute at Columbia University. [More]


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Awaiting Animals: Casting East African Wildlife "in a State of Being"

Photographer Nick Brandt spent months on dry lake beds and dusty plains, waiting to capture images of African wildlife in what he calls their "state of being". The animal assemblages that he saw through his lens are now revealed in A Shadow Falls, Brandt's book of stunning, sepia-toned portraits and panoramas released this month by Abrams. It is the second installment, after On This Earth: Photographs from East Africa, in his trilogy of books that Brandt hopes will memorialize "the vanishing natural grandeur of East Africa." [More]


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Readers Respond on "Knowing Your Chances"--And More...

Unintentional Comedy I have been really enjoying your magazine since I started reading it last year.

Readers Respond on "Obama's Science"

Tax Dollars at Work Despite Barack Obama appointing scientists to top posts, I hardly think this qualifies him personally to be named in the “ Scientific American 10 .” His inclusion pales beside the favor bestowed to the others on the list who have actually done some real work for science and humanity. [More]


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Recommended: The Age of Empathy

The Sibley Guide to Trees by David Allen Sibley. Knopf, 2009 [More]


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Earthquakes Exert Global Influence

[ The following is an exact transcript of this podcast. ]

A powerful earthquake beneath the Pacific triggers a tsunami that devastates Samoa and American Samoa. Another powerful temblor strikes off the coast of Sumatra. But is there a connection beyond the fact that both sit on the geologically active Ring of Fire that encircles the Pacific Ocean?  

Mediterranean dragonflies and damselflies disappearing with region's freshwater

As goes the water, so go the dragonflies. That's the finding of a new report from the IUCN concluding that one fifth of dragonflies and damselflies in the Mediterranean region are threatened with extinction as a result of increasing freshwater scarcity . Threats facing the insects include habitat degradation, pollution and climate change. [More]


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What (Maybe) Didn't Kill the Dinosaurs: Comets

The chunks of ice and dust that make their home in the Oort cloud, far beyond the orbit of Pluto, sometimes become dislodged and head into the solar system as streaky comets. Some disruptions, caused by passing stars and other interactions with the Milky Way galaxy, are severe enough to send Oort comets into orbits that buzz or even collide with Earth. New simulations have revealed a novel mechanism for their entry into our part of the solar system, a method that also suggests that comet showers may not have been strongly involved in major extinctions on Earth.

Comet dynamics depend heavily on Jupiter and Saturn: their huge gravitational fields tend to keep objects away from Earth. Comets that manage to skirt Jupiter and Saturn, the conventional thinking goes, had to have originated in the outer reaches of the Oort cloud, where perturbations from outside the solar system can be felt most strongly and are writ large across vast cometary orbits that take hundreds of years to complete. Only during comet showers caused by close stellar passages, the theory holds, have extreme gravitational disruptions brought inner Oort cloud comets into the mix.

EPA Announces Plan to Review Six Controversial Chemicals

Saying that the public is "understandably anxious and confused" about chemicals in their bodies and in their environment, President Obama’s top environmental official announced on Tuesday a new push to transform the way the nation regulates industrial compounds. [More]


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The Effect of Our Surroundings on Body Weight

Obesity is a “global epidemic,” according to the World Health Organization. Two thirds of American adults and one third of school-age children are either overweight or obese (defined as extremely overweight). These proportions have been rising steeply, report the latest surveys. From 1960 to 2002 the population of overweight and obese adults increased by roughly 50 percent, and the corresponding increase for children was 300 percent. Compounding the problem, obesity rates in other countries are rapidly approaching those in the U.S.

What is causing this pandemic, and what can we do about it? Researchers have provided some tentative answers that fly in the face of commonly held beliefs. They suggest that the increase in obesity may be a result of environmental changes that tempt us into unhealthy habits and tend to overwhelm our psychological defenses against consuming too much and succumbing to fattening fare. In fact, environmental cues can exacerbate any innate tendency to use food as a balm for jittery nerves or sadness. Thus, many health experts advocate legislation--for instance, a tax on junk food--that promotes healthy eating. Others are trying to help individuals change their immediate eating milieu in ways that discourage overeating.

How Quantum Effects Could Create Black Stars, Not Holes (preview)

Black holes have been a part of popular culture for decades now, most recently playing a central role in the plot of this year’s Star Trek movie. No wonder. These dark remnants of collapsed stars seem almost designed to play on some of our primal fears: a black hole harbors unfathomable mystery behind the curtain that is its “event horizon,” admits of no escape for anyone or anything that falls within, and irretrievably destroys all it ingests.

To theoretical physicists, black holes are a class of solutions of the Einstein field equations, which are at the heart of his theory of general relativity. The theory describes how all matter and energy distort spacetime as if it were made of elastic and how the resulting curvature of spacetime controls the motion of the matter and energy, producing the force we know as gravity. These equations unambiguously predict that there can be regions of spacetime from which no signal can reach distant observers. These regions--black holes--consist of a location where matter densities approach infinity (a “singularity”) surrounded by an empty zone of extreme gravitation from which nothing, not even light, can escape. A conceptual boundary, the event horizon, separates the zone of intense gravitation from the rest of spacetime. In the simplest case, the event horizon is a sphere--just six kilometers in diameter for a black hole of the sun’s mass.

Feds draft plan to help protect bats from deadly white-nose syndrome

Since its discovery in January 2007 the lethal fungal infection known as white-nose syndrome (WNS) has killed at many as 1.5 million bats in the U.S. Northeast. Now, as temperatures start to drop this autumn into the range where WNS operates at its optimal killing capacity , the U.S. Fish Wildlife Service (FWS) has drafted a plan to respond to the problem. [More]


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Why We Really Want to Go Back to the Moon

This year marked the 40th anniversary of two momentous events related to space exploration. One, the Apollo 11 moon landing on July 20, 1969, was a hallmark technological achievement. The other, the complete first run of Stanley Kubrick’s remarkable movie 2001: A Space Odyssey , vividly depicted author Arthur C. Clarke’s vision of humans traveling the solar system with abandon.

Much of the related flurry of reporting noted the stark differences between reality--people have not been back to the lunar surface since the December 1972 visit--and Clarke’s idea. Articles also asked whether the nation is sufficiently committed to devoting the $200 billion or so to returning to the moon 10 years from now and perhaps, after that, spending even more money to send humans to Mars.

Can Wind Power Be Stored?

Wind farms typically generate most of their energy at night, when most electricity demand is lowest. So a lot of that "green" energy is wasted.

So the big question is: How do you bottle that power for air conditioners and other appliances that are busiest during the day?

Privacy and the Quantum Internet (preview)

Privacy is hard to come by these days, particularly on the Internet, where every time you Google something your desires are recorded for posterity--or at any rate, for advertisers.

Internet search companies say they protect their clients’ privacy by encrypting personal information and by using numbers instead of names to give their users anonymity. The problem is that anonymization is not always effective. AOL user number 4417749 found this out the hard way in 2006 when AOL decided to publish online a list of 20 million Web searches, including hers and those of 657,000 other users. Reporters were able to track down the 62-year-old widow in Lilburn, Ga., by analyzing the content of her searches. Luckily, Thelma Arnold was relatively unembarrassed by the revelation of her identity and intimate interests. How many of us could say the same?

MIND Reviews: Neuro-Economic Boom

Does sex really persuade us to buy a product? Why do economies slip into depressions? And how much do we let our emotions influence our decision making? A spate of new books tries to answer these and other questions about how we make our choices, why they are sometimes so far off the mark and what their consequences are.

Animal Spirits--How Human Psychology Drives the Economy, and Why It Matters for Global Capitalism (Princeton University Press, 2009) examines the relation between economic fluctuations and psychological forces. Economists George Akerlof and Robert Shiller explore how “animal spirits”--the term coined by economist John Maynard Keynes to describe levels of consumer confidence--lie at the core of such questions as why there is unemployment and why minorities are often particularly poor.

Steven Chu to greenhouse gases: we will bury you

The U.S. Secretary of Energy-- channeling former Soviet leader Nikita Khrushchev perhaps?--has one thing to say in this week's Science to the greenhouse gases emitted by coal-fired power plants: we will bury you. Nobel Laureate Steven Chu's department has funneled $3.4 billion in stimulus dollars to research and develop the technology known as carbon capture and storage (CCS). [More]


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Linked Challenges: Climate Change and Energy Use

[ The following is an exact transcript of this podcast. ]

"The energy we use can sustain our planet, or destroy it." So said U.S. President Barack Obama yesterday while addressing the United Nations, talking about the twin challenges of climate change and energy consumption. [More]


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Uncharted waters: Hydrogen and the "law of unintended consequences"

Editor's Note: A team of Rensselaer Polytechnic Institute students are traveling up New York's Hudson River this week on the New Clermont , a 6.7-meter boat outfitted with a pair of 2.2-kilowatt hydrogen fuel cells to power the boat's motor. Their journey began September 21 from Manhattan's Pier 84 and will cover 240 kilometers (at a projected speed of 8 kilometers per hour). After making several stops along the way, the crew expects to arrive back at Rensselaer Polytech's campus in Troy, N.Y., on September 25. This is the third of Scientific American.com's blogs chronicling this expedition, called the New Clermont Project. [More]


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AIDS vaccine surprises scientists, proves partially successful

In an early-morning announcement today, researchers reported that an experimental HIV (human immunodeficiency virus) vaccine effectively reduced the number of people who contracted the virus by nearly a third. [More]


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