Posts

End without Horizons? In “Naked Singularities,” Pankaj S. Joshi argues that models for stellar collapse can produce naked singularities, or singularities without the event horizon that surrounds a black hole. According to quantum theory, black holes emit thermal radiation and evaporate because of the separation of particle-antiparticle pairs near their event horizon. Will a naked singularity ever disappear? Daniel Chamudot Riverdale, N.Y. If an event horizon has an extreme but finite spacetime curvature and gravity, and in a singularity these are infinite, how can there be any path between a low-gravity and curvature region and a singularity without passing through a horizon?...

Editor’s Note: This is the fifth in a series of six features on the science of food, running daily from March 30 through April 6, 2009. STATE COLLEGE, Pa.—Donald “Buster” Needham and his sons Artie and Don are moving their mushrooms out of Pennsylvania. Needham, 73, took over the business from his own father 50 years ago, but his West Grove operation—fueled with several hundred tons of steaming horse and chicken manure each week—has proved too stinky for city folk buying up homes in this township 40 miles (65 kilometers) west of Philadelphia....

DNA has long been considered the sole arbiter of heredity. New research seems to show, however, that its lesser known cousin, RNA–previously thought only to facilitate the creation of proteins as dictated by the genetic code–may itself pass traits down through the generations. Fifty years ago, researchers observed that the factors controlling the amount of purple coloring in certain corn kernels deviated from the accepted laws of genetics. Genetic variants that should have been bred out could sometimes exert their empurpling effect in subsequent generations....

Last Sunday, six Greenpeace activists boarded a ship named the Yang Ming Success in Hong Kong’s Victoria Harbor. Their mission: to prevent workers from unloading so-called e-waste, the toxic remnants of computers and other electronic devices. They succeeded—this time. The U.S. and some European countries often ship electronic junk to Hong Kong for disassembly in mainland China, where copper, iron and other valuable metals inside are removed and sold. Greenpeace and other environmental groups warn that workers, who wear little or no protective gear when they handle the devices, breathe in toxic heavy metals that include lung-damaging cadmium as well as lead and mercury (both known to cause brain damage)....

A biodegradable protein solution stanches bleeding in mere seconds when applied to open wounds in rodents, according to a new study. How the material works in detail is unclear, but it appears nontoxic and long lasting in animals, suggesting that it may either have advantages over existing bleeding stoppers or be able to complement them, researchers report. A number of different products are in use or are being developed to control bleeding on the battlefield and in routine surgery....

If you ever swim or paddle upstream, you will notice two things. First, a river’s speed varies a lot. Second, those variations should cause you to pull harder when you hit rapidly flowing water. If you don’t, you will simply make no progress. This puzzle replaces your muscles with a motor, but still asks you to figure out how to trade off energy for time. Here are the facts: • You want to go 72 kilometers (km) upriver....

For centuries men dominated academic science and engineering. Gender bias once greatly imperiled the progress of any woman inclined to pursue science, technology, engineering or math (STEM). Over the past 40 years, however, society has gradually begun to accept, if not embrace, the notion of the female biologist, mathematician or engineer, and the number of women in science at all levels has increased dramatically. In the early 1970s women received 29 percent of bachelor’s degrees and 10 percent of Ph....

One unintended side effect of Congress’s intense efforts to jump-start the U.S. economy is the threat of fraud. Earl Devaney, chair of a newly appointed federal watchdog agency, the Recovery Accountability and Transparency Board, has warned that without precautionary measures, as much as 7 percent of the stimulus package will end up in the hands of bad actors. Apply Devaney’s math to the $31 billion being spent on science—by the National Institutes of Health, NASA, the Departments of Commerce and Energy, and the National Science Foundation (NSF) combined—and stimulus funds represent an unprecedented boost not only for science, but also, potentially, for science fraud....

In 1935 Albert Einstein and his collaborators wrote two papers about what seemed to be vastly different things. One, which he famously later described uncomfortably as “spooky action at a distance,” is quantum entanglement: a surprising connection between objects, such as atoms or subatomic particles, which may be quite far apart. The other is wormholes, shortcuts between distant regions of space and time predicted by relativity. Work by theorists, including Juan Maldacena, author of this issue’s cover story, “Black Holes, Wormholes and the Secrets of Quantum Spacetime,” suggests a surprising link between the two phenomena....

I have always had a soft spot for the philosophical dreamers among us, and the ancient alchemists are no exception. Maybe it is partly because, in eighth grade, I was a serious little person with a 100 average in my science class and a very proud member of an after-school club called the Alchemists. (Our main function seemed to be to bring order to the Bunsen burners and various flasks.) But I think, beyond that, I have always admired the raw ambition of trying to transform something that has little value (such as base metals) into something that has a great deal (such as silver and gold)....

Key concepts Physics Sound wave Frequency Pitch Introduction Did you know the modern guitar is an instrument that dates back more than 4,000 years? The first written guitar music was published in the 16th century, during a time when guitars still had strings made from animal intestines! Although guitars have a long history, they are still extremely popular in modern day music. Have you ever wondered how they make the music you listen to everyday?...

The annual Lindau Nobel Laureate Meeting brings a wealth of scientific minds to the shores of Germany’s Lake Constance. Every summer at Lindau, dozens of Nobel Prize winners exchange ideas with hundreds of young researchers from around the world. Whereas the Nobelists are the marquee names, the younger contingent is an accomplished group in its own right. In advance of this year’s meeting, which focuses on physics, we are profiling several promising attendees under the age of 30....

The global health community has won many victories against infectious disease in the poorer parts of the world—eradicating smallpox in the 1970s and beating down the number of reported polio cases. Now it is turning to cancer and heart disease. The Institute of Medicine (IOM) in Washington, D.C., recently released a report warning that the rising tide of cardiovascular disease in low- and middle-income countries is threatening those nations’ economic well-being....

Readers responded in the comments thread to the blog posting, “Interactive Publishing: A Simpler Origin for Life.” Later, Shapiro answered some of these questions in “Responses from Shapiro.” The version in the June issue of Scientific American is shorter, but also includes figures, some of the questions and answers from the blog and a response from RNA-first researcher, Steven A. Benner of the Westheimer Institute for Science and Technology in Gainesville, Fla....

Originally posted on the Nature news blog A new year is a good time to make long-term plans, and NASA has jumped into the deep end of planning. On 20 December the US space agency’s astrophysics division released a wish list of future space missions — looking three decades into the future, and even beyond. The new ‘astrophysics road map’ is notable not because it restates broad and popular themes it thinks scientists should pursue, such as “Are We Alone?...

It sounds improbable: a documentary film about global warming, starring Vice President Al Gore, has become the third-highest-grossing documentary of all time. After his loss in the 2000 presidential election, Gore began giving a talk on global warming to audiences around the world. An Inconvenient Truth is the film version (also appearing in book form) of his multimedia presentation. Remarkably, its heavy use of PowerPoint slides actually adds to the narrative, which interweaves explanations of climate science with defining episodes from Gore’s life to convey a mix of alarm and hope....

Late in the 19th century an unknown artist depicted a traveler who reaches the horizon, where the sky meets the ground. Kneeling in a stylized terrestrial landscape, he pokes his head through the firmament to experience the unknown [see illustration on next page]. The image, known as the Flammarion engraving, illustrates the human quest for knowledge. Two possible interpretations of the visual metaphor correspond to two sharply different conceptions of knowledge....

The Astronomer and the Witch: Johannes Kepler’s Fight for His Mother by Ulinka Rublack Oxford University Press, 2015 (($29.95)) Johannes Kepler was a renowned 17th-century German astronomer, mathematician, natural philosopher … and lawyer? Although he is not known for the last occupation, in 1620 he put his work on hold, packed up his household and moved back home to Württemberg, Germany, to defend his mother in court on charges of witchcraft....

Lights and video displays made with energy-efficient light-emitting diodes (LEDs) are already making strong inroads in consumer and industrial markets long dominated by fluorescent bulbs and liquid crystal displays (LCDs). Although the majority of these LEDs get their electroluminescence from layers of film made from carbon-containing organic compounds, such organic LEDs (OLEDs) may be superseded by LEDs made from inorganic compounds that shine brighter and last longer than OLEDs. The life spans of inorganic LEDs (ILEDs) can be 100,000 hours or more, much longer than OLEDs....

MADISON, Wis.–Trey Mackey expertly baits his fishing hook with a live worm, sits down on a folding chair and casts a line into the waters of Monona Bay. He’s driven up from Chicago for a day of fishing that could provide a fresh, tasty dinner of blue gill. But unbeknownst to Mackey, consuming fish from the bay carries a significant health risk. Every state, including Wisconsin, has issued health advisories for an array of rivers, lakes and bays that warn of the dangers of eating fish tainted with industrial compounds and other chemicals....