Discover July - August 2015的目錄

Welcome to our annual Invisible Planet issue, focusing on the little known, the hidden or hard to understand, the science we don’t see. As in previous years, I like to use this page to praise the hard work of the invisible planners — the Discover staffers and contributors who work hard to bring you the stories you’ll find in this extra-large issue. Our “Powering the Future” section (page 50) deserves special commendation. The concept was initially developed by Contributing Editor Dan Ferber. Associate Editor April Reese and Associate Art Director Alison Mackey spent many weeks coordinating the words and pictures for this impressive 24-page extravaganza, which showcases innovative renewable energy technologies. Another contributing editor, Jeff Wheelwright, and Managing Editor Kathi Kube also deserve shout-outs for their parts in launching History…

THE STRANGE CASE OF THE RICKETY COSSACK By Ian Tattersall Venerable paleoanthropologist Tattersall opens his latest book recalling the time when, as a young researcher in the ’70s, he traveled to the Comoros Islands to study lemurs and instead found himself in the midst of a coup. But Strange Case is more than reminiscing. It’s an insightful look at how — and why — we Homo sapiens so often get human evolution wrong. Tattersall makes it clear that he’s arguing his interpretation of the fossil record, but even his opponents will find themselves chuckling at many of his wry, sometimes withering critiques, from the near-comical initial interpretation of the first Neanderthal skeleton to be unearthed (referenced in the book’s title) to ongoing debate on whether our family tree is actually…

Schönau im Schwarzwald, Germany — Coming off the twisting mountain road that cuts through the heart of the Black Forest, the village of Schönau looks like something out of Grimm’s fairy tales. Small shops and rustic beer gardens line narrow streets built for horses and foot traffic. Dairy cattle, a rare variety bred here centuries ago to be as sure-footed as mountain goats, graze on steep-pitched pastures high above the village. From the highway north of town, Schönau appears much as it did in the 12th century. Viewed from the south, however, Schönau looks quite different. The sun glints blue off thousands of rooftop photovoltaic (PV) panels — small, grid-connected power plants owned by residents. The panels generate more electricity on sunny days than the village of 2,500 people consumes.…

The Latest Science News & Notes Being stripped of planetary status may be the best thing that ever happened to Pluto. For decades, it seemed like little more than a celestial misfit, much farther out than the solid, Earth-like worlds and far smaller than the giant, gassy ones. But in the nine years since Pluto’s demotion, astronomers have come to appreciate that its oddity is actually an indication of its importance. When the New Horizons spacecraft flies past Pluto on July 14, it will arrive not at the smallest planet but at the brightest and most intriguing member of the Kuiper Belt, the unexplored outer territory of the solar system. Alan Stern — principal investigator on New Horizons and the No. 1 Pluto booster out there — proudly calls his…

Standing on Einstein’s Shoulders The cover of our April issue boasted the cover line “Outsmarting Einstein,” part of our special section celebrating the 100th anniversary of the general theory of relativity. “Outsmarting Einstein,” while catchy, is an unfortunate phrase. Modifying his general theory of relativity would be an enormous intellectual achievement, and the people trying to do so are by no means dummies. But, in place of his pencil and paper, they have a century of experiments upon which to build, as well as incredible instruments and budgets. If his theory is eventually modified, he certainly will not have been outsmarted. Al Wagner Shoreline, WA Species Resurrection March’s “Jurassic Ark” feature explored the science and ethics of de-extinction for animals such as the woolly mammoth, dodo, ibex and Steller’s sea…

University of Southern Denmark researchers have discovered a way heavy metal might help patients with lung disease. We’re not talking Black Sabbath. The heavy metal is cobalt, in the form of a crystalline salt. A mere 10 liters — about a bucketful — is enough to suck up a room’s worth of oxygen. Oxygen stored in the crystalline salt can then be released as needed. Another bonus? That 10 liters of special salt holds three times the oxygen as a conventional tank of the same size, possibly rendering bulky scuba tanks and portable oxygen therapy equipment obsolete. Using pressurization, it could allow lung disease patients and deep-sea divers to draw oxygen directly from their environment using special masks. Other possibilities include regulated oxygen supply for fuel cells in electric cars.…

You may lament your short life span, but cheer up! Your impending death means you won’t have to endure billions of horrific years to come. In 2014, scientists found another reason to rejoice in your genes’ deterioration: White dwarf stars, like the remnant that will remain at the end of the sun’s life, eat rocky planets like Earth for their last meal. Here are a few more milestones to be grateful to miss. 1.1 billion years The sun is 10 percent brighter. The extra heat hitting Earth’s surface causes water to begin to boil off into space. No more yachts, no more Powerade, no more fun. 3.5 billion years After eons of such heat, the sun has turned our planet into a true twin of Venus: dry, hot and dead.…

1480s Leonardo da Vinci does the first real studies of flight. He produces designs for gliders, parachutes and human-powered helicopters. 1783 The skies around Paris are unexpectedly busy in the waning months of 1783. In September, brothers Joseph and Etienne Montgolfier launch a hot air balloon that reaches an altitude of about 1,700 feet. The first passengers are animals; they survive. Two months later, so do the first men to go aloft in a Montgolfier balloon. (But one of them, Jean-Francois Pilatre de Rozier, would have the dubious honor of being one of the first men killed in a balloon crash, two years later). In December, Jacques-Alexandre-Cesar Charles and Marie-Noel Robert take to the skies in a hydrogen balloon, complete with wicker gondola and a valve-and-ballast system to control ascent…

When you encounter, say, some neighbors who refuse to vaccinate their children because of long-debunked fears of autism and mercury poisoning, it’s tempting to throw facts at them. But — as you know if you’ve ever tried this approach — bombarding people with evidence is doomed to fail. If you want any chance of engaging in a meaningful conversation, you’ll need better tactics. Here are six worth trying. We can’t promise they’ll work, but they’ll give you a fighting chance. Be a good listener and make a connection. As much as we’d like to think otherwise, most human judgments aren’t based on reason, but on emotion, says Ditto, the UC Irvine psychologist. Aim to forge a personal connection that makes the other person inclined to see you as “one of…

Nowhere on Earth does the sun shine as brightly as it does in geosynchronous orbit, that parking space 22,236 miles up where a satellite can keep a spot on Earth in steady view all day, every day. Placed high above the gauzy atmosphere, solar panels can intercept rays 35 to 70 percent more intense than midday sunlight on the ground. In high orbit, there is no cloud cover, no twilight, no wan winter sun. And a cleverly designed and positioned solar satellite can avoid the shadow of night for all but 44 hours a year, so there is no need to store energy to keep the electrons flowing almost continuously. All told, an advanced photovoltaic cell in space can deliver up to 40 times the annual amount of reliable 24/7…

Deep inside the massive Z machine at Sandia National Laboratories in Albuquerque, N.M., a tiny cylinder of beryllium, no bigger than a pencil eraser, awaits its big moment. The capsule holds a smidgen of neutron-rich hydrogen gas, hardly enough to make a small pop if you burned it. But the physicists at Sandia have in mind a grander plan than combustion, one that will release kilowatts of power from this tiny capsule: thermonuclear fusion. It’s the same process that heats the sun, and the Z machine team is testing a promising new way to transform it into a clean and plentiful source of electricity on Earth. Red lights flash, and a loud horn sounds. Rivers of electrical current fill banks of capacitors. Nineteen-million amps of current zap through the machine…

Buildings consume 73 percent of the United States’ electricity and produce 38 percent of its carbon dioxide emissions. “We need a change,” says Eric Corey Freed, vice president of global outreach for the International Living Future Institute. The gold standard in energy efficiency, known as net zero, calls for every building to generate 100 percent of the energy it consumes, but Freed believes builders can go further. Enter the institute’s Living Building Challenge (LBC), a certification program for buildings that aren’t just energy efficient but also regenerative — they produce more power than they use and promote well-being. LBC projects use smart technology, including thermostats that learn when to turn off the heat and “daylighting,” which allows natural light to permeate the space. The Bullitt Center in Seattle uses both, along…

In February 1809, Francisco José de Caldas, director of the Astronomical Observatory in Bogotá in present-day Colombia, addressed an issue that everyone was talking about — namely, the weird sky and crazy weather. Caldas published a weekly newsletter about science called Semanario del Nuevo Reyno de Granada. Under the headline “Meteorological News,” he described how the sun had changed its appearance since the previous Dec. 11. Choked by a high, thin cloud, the sun had lost its brightness, “so much so that many have mistaken it for the moon.” The sky was milky, not at all blue, and at night the lesser stars seemed to have disappeared. Plus, the weather had been unnaturally cold, the fields covered with ice and crops damaged. “So many have consulted me, and so many…

You know what it’s like to have an itch that you just can’t scratch? That’s how I feel whenever astronomers discover an intriguing new planet around another star — especially the recent reports of planets like Kepler 438b and Gliese 667 Cc that seem similar to Earth in size and temperature. Are they host to alien life? Are they strange, deadly worlds like Venus, or something completely bizarre, unlike anything we’ve seen before? I am restless to go there and get a look. Judging by the many comments I’ve received and seen online, I’m not the only one. But man, is it a hard itch to scratch. The distances between stars are immense. Consider Voyager 1, the fastest spacecraft in the solar system. It took 18 months to reach Jupiter.…

Per capita potato consumption dropped to an all-time low recently. To boost consumer interest, American potato breeding programs are selectively breeding smaller, more colorful varieties. The flashier hues mean more phytonutrients, compounds linked to a variety of health benefits, and their compact size means shorter cooking times. Breeding those traits takes 12 to 14 years, says Texas A&M program director J. Creighton Miller Jr., but you won’t have to wait that long to see one of the program’s newest creations, a variety called peppermint. It sports white skin speckled with red, and it could arrive in stores later this year. Don’t worry; the name only reflects the potato’s color, not its flavor.…

In 2007, John Scott, who had extreme food and environmental allergies, chronic fatigue and Crohn’s disease, participated in a Nottingham University study to test the safety of hookworms (Necator americanus) on Crohn’s patients. It was a placebocontrolled study, but Scott assumed he received worms because his condition improved. So when the study ended, he wanted the worms back. Scott’s idea to infect himself with roughly centimeter-long worms was not an outlandish plan: Do-it-yourself worm therapy as a way to treat autoimmune disorders has become more common in the past decade. Since humans evolved with parasites and bacteria, some scientists believe the immune system works in tandem with these creatures to keep us healthy. Hookworms have had millennia to develop “exquisite strategies” to suppress their host’s inflammation, doing as little harm…

Astronomers have a new tool to hunt the brightest and nearest exploding stars: ASAS-SN. The two observatories of the All-Sky Automated Survey for Supernovae scan the Northern and Southern hemispheres every night with six 5.5-inch telescopes (eight total by the end of the summer), taking photos of the sky and comparing successive images to find changes, such as supernovas. At $100,000 per pair of telescopes, a bargain in professional astronomy, ASAS-SN proves that small projects can do big science: Since coming online in 2013, it has already found more than 100 supernovas, almost half of the total number of similar discoveries.…

Although the atmosphere seems invisible and gaseous, it’s a more apt description to say we’re surrounded by an ocean of air that acts more like a fluid. Drag, lift, thrust and gravity — all must be considered when designing an aircraft. Drag exerts force on an object moving through a fluid. The more sleek the object, the easier it moves through the medium. Weight represents the downward pull of gravity. Skydivers fall like rocks before pulling parachutes to maximize drag forces and slow their descent. Lift is exerted on the object as it moves. Generally, lift is directed up, perpendicular to the drag force. Gliding is a modified form of parachuting. The airfoil — that web of fabric between the legs of a wingsuited birdman — sometimes provides lift but…

In the digital age, information is more plentiful than ever, but parsing truth from the abundance of competing claims can be daunting. Whether the subject is Ebola, vaccines or climate change, speculation and conspiracy theories compete with science for the public’s trust. Our guide to rational thinking is here to help. In the following pages, you’ll learn tools to identify the hallmarks of irrational thinking, evaluate evidence, recognize your own biases and develop strategies to transform shouting matches into meaningful discussions. The Irrationalist in You We’re programmed for irrational thought. Irrational thinking stems from cognitive biases that strike us all. “People don’t think like scientists; they think like lawyers. They hold the belief they want to believe and then they recruit anything they can to support it,” says Peter Ditto,…

Aside from humans, horses are one of the few mammals that sweat to regulate body heat. 1 Composed of about 99 percent water, sweat evaporates on the skin’s surface, cooling the body and keeping it from overheating. 2 Sweat secretions help you in other ways, too. They include dermcidin, an antibiotic peptide that appears to regulate bacteria growth on the skin and may fight infection. 3 Not all humans sweat equally. Men sweat up to twice as much as women, and both sexes sweat less with age. 4 The sensation of touch can trigger a “sweat reflex” on the opposite side of the body from the spot that is touched. 5 Sweat can trigger other responses: People with atopic dermatitis, a skin condition, can experience an immediate and serious allergic…