Highly focused acoustic pulses could produce superior acoustic images, be used as sonic scalpels, and probe for damage in bridges, boat hulls, and other opaque materials.

Taking inspiration from a popular executive toy ("Newton's cradle"), researchers at the California Institute of Technology (Caltech) have built a device - called a nonlinear acoustic lens - that produces highly focused, high-amplitude acoustic signals dubbed "sound bullets."

The acoustic lens and its sound bullets (which can exist in fluids - like air and water - as well as in solids) have "the potential to revolutionize applications from medical imaging and therapy to the nondestructive evaluation of materials and engineering systems," says Chiara Daraio, assistant professor of aeronautics and applied physics at Caltech and corresponding author of a recent paper in the Proceedings of the National Academy of Sciences (PNAS) describing the development.

NASA's recently launched Solar Dynamics Observatory, or SDO, is returning early images that confirm an unprecedented new capability for scientists to better understand our sun's dynamic processes. These solar activities affect everything on Earth.

Some of the images from the spacecraft show never-before-seen detail of material streaming outward and away from sunspots. Others show extreme close-ups of activity on the sun's surface. The spacecraft also has made the first high-resolution measurements of solar flares in a broad range of extreme ultraviolet wavelengths.

"These initial images show a dynamic sun that I had never seen in more than 40 years of solar research," said Richard Fisher, director of the Heliophysics Division at NASA Headquarters in Washington. "SDO will change our understanding of the sun and its processes, which affect our lives and society. This mission will have a huge impact on science, similar to the impact of the Hubble Space Telescope on modern astrophysics."

Launched on Feb. 11, 2010, SDO is the most advanced spacecraft ever designed to study the sun. During its five-year mission, it will examine the sun's magnetic field and also provide a better understanding of the role the sun plays in Earth's atmospheric chemistry and climate. Since launch, engineers have been conducting testing and verification of the spacecraft's components. Now fully operational, SDO will provide images with clarity 10 times better than high-definition television and will return more comprehensive science data faster than any other solar observing spacecraft.

SDO will determine how the sun's magnetic field is generated, structured and converted into violent solar events such as turbulent solar wind, solar flares and coronal mass ejections. These immense clouds of material, when directed toward Earth, can cause large magnetic storms in our planet's magnetosphere and upper atmosphere.

SDO will provide critical data that will improve the ability to predict these space weather events. NASA's Goddard Space Flight Center in Greenbelt, Md., built, operates and manages the SDO spacecraft for the agency's Science Mission Directorate in Washington.

NASA's Spitzer Space Telescope has discovered something odd about a distant planet -- it lacks methane, an ingredient common to many of the planets in our solar system.

"It's a big puzzle," said Kevin Stevenson, a planetary sciences graduate student at the University of Central Florida in Orlando, lead author of a study appearing tomorrow, April 22 in the journal Nature. "Models tell us that the carbon in this planet should be in the form of methane. Theorists are going to be quite busy trying to figure this one out."

The discovery brings astronomers one step closer to probing the atmospheres of distant planets the size of Earth. The methane-free planet, called GJ 436b, is about the size of Neptune, making it the smallest distant planet that any telescope has successfully "tasted," or analyzed. Eventually, a larger space telescope could use the same kind of technique to search smaller, Earth-like worlds for methane and other chemical signs of life, such as water, oxygen and carbon dioxide.

"Ultimately, we want to find biosignatures on a small, rocky world. Oxygen, especially with even a little methane, would tell us that we humans might not be alone," said Stevenson.

So, the headlines say somebody else has died due to video game addiction. Yes, it's Korea again.

What the hell? Look, I'm not saying video games are heroin. I totally get that the victims had other shit going on in their lives. But, half of you reading this know a World of Warcraft addict and experts say video game addiction is a thing. So here's the big question: Are some games intentionally designed to keep you compulsively playing, even when you're not enjoying it?

Oh, hell yes. And their methods are downright creepy.

Tomorrow, the US Air Force will finally launch the long-delayed X-37B unmanned mini space shuttle, dubbed by the Iranian government a "secret space warplane". But what is it actually for?

Probably nothing hostile, most of the time, is the answer. But it could do some quite naughty and interesting things if required - and what's more, it could probably do them without anyone knowing about it.

The X-37 has had a long and chequered development history. It was built by Boeing's "Phantom Works" advanced-concepts shop, originally for NASA - though it had Air Force heritage from the beginning, drawing heavily on the USAF's X-40 experiments.

NASA saw the craft as a potential "lifeboat" for the International Space Station, but that requirement wouldn't really call for a winged re-entry vehicle: the ISS lifeboat is in fact a common-or-garden Soyuz capsule - perhaps now to be replaced at some point by an American Orion salvaged from the ruins of the Constellation moonbase programme. Neither has wings, or any real need for them.

A previously unknown letter penned by the nation's sixth president, John Quincy Adams, has been found in a dusty box in the basement of Quincy City Hall.

The letter, dated Sept. 8, 1826, outlines the burial wishes of Adams' father, John Adams, the nation's second president.

The letter was recently discovered by a city attorney who was combing through some old city records.

John Quincy Adams wrote that his father, who had died two months earlier, and his mother, Abigail Adams, wished to be buried in the First Parish Church, and that a "plain and modest monument" be built in their memory.

John and Abigail Adams are buried in the basement of the church, as are John Quincy Adams and his wife, Louisa Catherine.

A 3,000-year record from 52 of the world's oldest trees shows that California's western Sierra Nevada was droughty and often fiery from 800 to 1300, according to new research.

Scientists reconstructed the 3,000-year history of fire by dating fire scars on ancient giant sequoia trees, Sequoiadendron giganteum, in the Giant Forest of Sequoia National Park. Individual giant sequoias can live more than 3,000 years.

"It's the longest tree-ring fire history in the world, and it's from this amazing place with these amazing trees." said lead author Thomas W. Swetnam of the University of Arizona in Tucson. "This is an epic collection of tree rings."

The new research extends Swetnam's previous tree-ring fire history for giant sequoias another 1,000 years into the past. In addition, he and his colleagues used tree-ring records from other species of trees to reconstruct the region's past climate.

The scientists found the years from 800 to 1300, known as the Medieval Warm Period, had the most frequent fires in the 3,000 years studied. Other research has found that the period from 800 to 1300 was warm and dry.

Genetic data points to ancient liaisons between species.

Archaic humans such as Neanderthals may be gone but they're not forgotten - at least not in the human genome. A genetic analysis of nearly 2,000 people from around the world indicates that such extinct species interbred with the ancestors of modern humans twice, leaving their genes within the DNA of people today.

The discovery, presented at the annual meeting of the American Association of Physical Anthropologists in Albuquerque, New Mexico, on 17 April, adds important new details to the evolutionary history of the human species. And it may help explain the fate of the Neanderthals, who vanished from the fossil record about 30,000 years ago. "It means Neanderthals didn't completely disappear," says Jeffrey Long, a genetic anthropologist at the University of New Mexico, whose group conducted the analysis. There is a little bit of Neanderthal leftover in almost all humans, he says.

The researchers arrived at that conclusion by studying genetic data from 1,983 individuals from 99 populations in Africa, Europe, Asia, Oceania and the Americas. Sarah Joyce, a doctoral student working with Long, analyzed 614 microsatellite positions, which are sections of the genome that can be used like fingerprints. She then created an evolutionary tree to explain the observed genetic variation in microsatellites. The best way to explain that variation was if there were two periods of interbreeding between humans and an archaic species, such as Homo neanderthalensis or H. heidelbergensis.

"This is not what we expected to find," says Long.

A researcher from UCL is part of a US-led team investigating how the brain and its microcircuitry react to physiological changes and what could be done to encourage its recovery from injury.

Dr Maneesh Sahani (UCL Gatsby Computational Neuroscience Unit) is part of the team led by Stanford University and Brown University.

The project will explore the use of a new generation of 'optogenetic' devices small enough to be implanted in the brain, where they would simulate the function of damaged tissue.

The Reorganization and Plasticity to Accelerate Injury Recovery (REPAIR) project, funded by the US government, involves researchers from UCL, Stanford, Brown, and the University of California at San Francisco (UCSF).

Together their expertise spans neuroscience, neurology, psychiatry to semiconductor micro- and optoelectronics, statistical signal processing, machine learning, and brain modelling.

Feline saboteur 'fried everything' at command base

Control over heavily armed US war robots fighting in Iraq and Afghanistan was lost last year after a cat climbed into machinery at an American command base and "fried everything", a US officer has confirmed.

The news comes from Colonel Grant Webb, describing technical problems at Creech Air Force Base outside Las Vegas, Nevada. This is famously the location from which US Air Force "Predator" and "Reaper" robot aircraft are controlled during missions overseas*.

"A cat climbed into one of the electronic nodes and fried everything," the colonel says (skip to about 1:10 seconds in the vid below). We're indebted to the excellent DEW Line blog for the vid - and speculative analysis suggesting that the feline saboteur was in fact a highly trained al-Qaeda suicide martyr moggy.