Discover的November 2015目录

After decades of searching, astronomers have finally found a medium-size black hole. About 12 million light-years distant in galaxy M82, middleweight M82 X-1 is bigger than the black holes left over from stars’ deaths, but it’s not big enough to be supermassive. Astronomers had long thought such in-betweeners might exist and believed they might be catching glimpses of them, but they had no solid proof. University of Maryland’s Dheeraj Pasham set out to change that. While no one can see a black hole by definition, an X-ray telescope can see the orbiting material around that black hole, which is so hot it emits high-energy radiation. Pasham studied six years’ worth of X-ray data from M82 X-1. He found two repeating signals. The time between blasts gives clues about how fast…

“But can I still go to the Virgin Islands?” Ellen, 51, vivacious and trim, looked the perfect candidate for some fun in the sun. “I feel fine. It was only a minute or two,” she said. “I’m sure you’re OK,” I said. “But better to do all the tests quickly in the hospital and start treatment.” “I do everything right.” She ticked off her fingers, “I work out. I quit smoking. I even skip birthday cake!” “The CT scan and your lab work look good so far.” “Do I really need to stay overnight?” I held her shoulder. “We’ll get the MRI in a few minutes, then we need some heart tests. It would make me much happier if you stayed.” It started with a phone call. “Couldn’t move her…

Israel Finkelstein used microarchaeology to find any trace of David and Solomon’s kingdoms within a slice of six partially dated cities, stacked below, atop and inside Tel Megiddo. The site, pictured right, is divided into specific areas of excavation. Assyrian city built after invasion in 732 B.C. caps the tel’s Iron Age layers. Monumental Israelite city, notable for a massive wall and two pillared buildings, widely considered stables. Built by the Omrides of the north. Finished-stone ashlar palaces and other structures of high civilization are woven through Yigael Yadin’s Solomonic tales. Finkelstein also identified it as belonging to the Omride Dynasty. A slum so crudely wrought, its builders did not even bother to clear the rubble. Red burnt brick city. This rich cosmopolitan world represented the last of Canaanite culture.…

OR MILLENNIA, MYTHOLOGY HAS SERVED as a vessel for passing down traditions and knowledge in countless cultures. Sometimes, though, these tales seem a little too tall, especially those of magic that transforms men into beasts. But if you examine them closely, there are some slivers of truth, and they might actually be based in science. Among the most famous of these myths is part of Homer’s The Odyssey. During their wanderings, Odysseus and his crew arrive at the island of Aeaea. Starving and exhausted, they split into two groups to search for resources, and one group stumbles upon a palatial home. A beautiful woman emerges and welcomes the men inside for a feast. All but one of them follow her. This is no ordinary woman. This is the sorceress Circe…

Drama is coming to the U.S. On August 21, 2017, Sun-watchers along a line from Oregon to South Carolina will experience nature’s grandest spectacle: a total solar eclipse. It’s likely to be the most viewed sky event in history. That’s why even now, nearly two years before the eclipse, astronomy clubs, government agencies, cities, and even whole states are preparing for the unprecedented onslaught of visitors whose only desire is to experience darkness at midday. This will be the first total solar eclipse crossing the continental U.S. in 38 years (totality touched Hawaii on July 11, 1991). The last one occurred February 26, 1979. Unfortunately, not many people saw it because you had to be in (or travel to) a narrow path crossing one of just five states in the…

WATER FAIRIES These egg-beater-shaped structures are actually water-repellent hairs found on the leaves of Salvinia natans, or water ferns. About a millimeter tall, the hairs — known as superhydrophobic trichomes — trap a thin layer of air between the fern leaves and the surrounding liquid to improve stability in water. The Salvinia effect has drawn the attention of researchers developing coatings that could reduce the drag created by ships’ hulls traveling through water.…

Q Where do different flu strain names, like H1N1 and H7N9, come from? — Claudia Mulder, Perth Amboy, NJ A First, let’s take a step back. Influenza viruses are divided into three categories: A, B and C, depending on their antigen protein type. (Antigens are any foreign substance that can stimulate an immune response, typically spurring antibody production.) Whereas type C can cause mild respiratory illness and B seasonal epidemics, type A can lead to serious worldwide pandemics and is the type you’re most likely to hear about in the news. The World Health Organization, which adopted the classification system in 1979, further divided influenza A based on its surface glycoproteins, hemagglutinin (H) and neuraminidase (N). Hemagglutinin, which plays a role in how the virus binds to host cells, has…

The more your parents bond before you’re born, the better adjusted you’ll be — at least if you’re a Japanese quail. Researchers at the University of Rennes in France studied how bonding in this monogamous species might affect their progeny. They looked at 30 male-female pairs, some of which developed close bonds by staying together all the time, while others met just three times a week for sex. Those bonds mattered: Chicks from the tight-knit parents were more social and less fearful. DID YOU KNOW? In eastern Washington state, “habitat-enhanced” vineyards — which have added native plants as a strategy to increase “good” insects and reduce pests — are attracting four times as many butterflies as conventional vineyards. We’ll drink to that.…

Driving north to Tel Megiddo, I am traveling back in time. Receding behind me, the Wi-Fi cafe culture of Tel Aviv, the white city on the beach. Looming ahead, Highway 6, tracing the Via Maris, the major trade route of the ancient world. Stretching from Egypt to Mesopotamia (present-day Iraq), the road passed the overlook city, Megiddo, making the community atop the mound a player in the history of wars and men. One of the most embattled sites of antiquity, Megiddo has another name: Armageddon, the place the book of Revelation says we will savage each other in the last days of Earth. Back in Tel Aviv, sirens will soon be sounding, the Iron Dome defense system blasting missiles out of the sky. Atop Tel Megiddo, I’ll mainly hear wind…

Eutiara “This wonderful creature is a completely new species,” says Anthony Berberian. It seems to be a jellyfish from the Eutiara genus, family Pandeidae. The umbrella is less than an inch long, but the tentacles are about 3 feet. Like similar tentacled invertebrates, it is likely venomous. Jellyfish specialist Jacqueline Goy is working on a paper with the pair to describe and name it. For the past few years, a pair of French Polynesian photographers have been taking outsize risks to study the smallest of creatures off the Tahiti coast. Fabien Michenet and Anthony Berberian are physicians by day, but at night they dive between 66 and 164 feet underwater to document an astonishing diversity of plankton species. These tiny, free-drifting creatures are rarely seen in the wild, a few…

In 2013, a 400-pound research drone went missing off the coast of Alaska, threatening the very environment that the scientists were studying. Fortunately, the fuel tank didn’t rupture, and fishermen recovered the wreckage without mishap. But the near-miss inspired NASA biologist Lynn Rothschild to design a new kind of drone: one that would have minimal environmental impact if it crashed because it would be made of biodegradable materials, such as bacteria and fungus. Although Rothschild says it “looks sort of like a dried whole wheat sandwich,” the prototype her team developed is flightworthy. And future iterations of her biodrone — such as the one illustrated at right — might even be designed to fly one-way missions that end in an intentional crash, providing a snack for Alaskan salmon when the…

If you could shrink yourself down to the size of a bacterium and explore a watery pool, your normal swimming technique would soon prove worthless. Liquids feel thicker, more like moving through honey than water, and tiny swimmers are easily jostled off course. So when an international team of engineers wanted to design tiny robots that could move cells around, deliver drugs deep inside the body or clean clogged arteries, they looked to nature for inspiration: sperm. The team’s “magnetosperm” are small, about the size of a dust mite, but six times longer than a human sperm cell. Their design mimics the familiar swimmer’s physique, with a thin magnetic disk added to the head. To get the sperm to swim in liquid, the researchers switch on an oscillating magnetic field…

The contrast couldn’t be more stark: Only a chainlink fence, camouflaged by thick bushes and mighty oak trees, separates residents from a Shell chemical plant and the Motiva oil refinery. On one side is a verdant park, with a gazebo and a children’s slide, surrounded by a handful of small, tidy clapboard homes with well-tended lawns. On the other side is a huge industrial zone: low-slung concrete and corrugated buildings, and vast storage tanks connected by a maze of thick pipes. Smokestacks spew clouds of noxious chemicals. This is the Diamond district of Norco, a Mississippi Delta hamlet about 25 miles west of New Orleans. It’s like a ghost town now — empty and quiet, even at midday. Tall grasses have overtaken open fields where homes once stood. This used…

The afternoon skies were clear and blue like countless centuries of others in Chile’s Atacama Desert when the blast rang out. The explosion shattered the silence and sent rock high into the thin Andean air. Some 70 controlled detonations would follow, removing millions of cubic feet of dirt to flatten the peak of Cerro Las Campanas for the nearly $1 billion Giant Magellan Telescope. But this won’t be the only highdollar instrument in the Atacama Desert. Nearby, work has begun on the Large Synoptic Survey Telescope, designed to image the entire visible sky every few nights. To the north, Europeans are constructing their Extremely Large Telescope, which will one day be the world’s largest. Combined with the recently finished Atacama Large Millimeter/submillimeter Array, these projects will cost more than $4…