Why are supermassive black holes so, well, supermassive? It has long been a mystery how enough matter can reach these cosmic gluttons to swell them to such large sizes. Now it seems the answer could be connected to a starry disc at the heart of the Andromeda galaxy. Although they may be hard to see, such discs may be common.

Black holes millions or billions times as massive as the sun reside at the heart of most galaxies, including our own. These black holes have been fattened up by huge amounts of gas. But astronomers don't know how that gas makes it through a final hurdle, migrating the last dozens or hundreds of light years to be eaten.

Philip Hopkins and Eliot Quataert of the University of California, Berkeley, suggest that the formation of a skewed ring of stars facilitates the flow of gas, by sapping its momentum so that it spirals in towards the black hole.

Nap-time reveries may show that sleeping brain is making memories

People who have nap-time dreams about a task that they've just practiced get a big memory boost on the task upon awakening, Harvard researchers report.

Those who dream about anything else have no such enhanced recall, the team reports in a paper published online April 22 in Current Biology. Neither do those who stay awake, even if they think about the task.

"I was startled by this finding," says study coauthor Robert Stickgold, a cognitive neuroscientist at Harvard Medical School. "Task-related dreams may get triggered by the sleeping brain's attempt to consolidate challenging new information and to figure out how to use it.

A new study in the journal Icarus provides the latest round-up of the number of impact craters found on Saturn's moon Titan.

Between 2004 and December 2007, Cassini had surveyed 22 percent of Titan's surface. Scientists analyzed images taken by the spacecraft's high-resolution Radar Mapper instrument, and found 49 impact craters.

"Impact craters are created on every planet because of asteroids, comets and other debris that collide with their surfaces," said Charles Wood, senior scientist at the Planetary Science Institute in Tucson, Az, and lead author of the study. "Analyzing impact craters is a standard technique to tell you the history of the world."

There's a lot of circumstantial evident that mtDNA haplogroup U5 was brought to Europe by the first anatomically modern populations. Though this haplogroup is extant around frequencies of ~10% in modern European populations, with the highest proportions in northern Fenno-Scandinavia and the east Baltic region, extractions of DNA from hunter-gatherer remains in northern Europe yield very high proportions of this lineage.

This is not totally surprising, in the early aughts Bryan Sykes wrote a book, The Seven Daughters of Eve, and correctly pointed out that the coalescence for the U5 lineages is very deep in Europe, suggesting that it has had a lot of time to diversify. Sykes' main thesis though was that most of the genetic heritage of Europe predates the expansion of Neolithic farmers within the last 10,000 years. The rough implication was that ~80% of the ancestry of modern Europeans could be derived from people who were resident within the modern boundaries of the continent of Europe during the last Ice Age.

The Cat's Paw Nebula, NGC 6334, is a huge stellar nursery, the birthplace of hundreds of massive stars. In a magnificent new ESO image taken with the Visible and Infrared Survey Telescope for Astronomy (VISTA) at the Paranal Observatory in Chile, the glowing gas and dust clouds obscuring the view are penetrated by infrared light and some of the Cat's hidden young stars are revealed.

Towards the heart of the Milky Way, 5500 light-years from Earth in the constellation of Scorpius (the Scorpion), the Cat's Paw Nebula stretches across 50 light-years. In visible light, gas and dust are illuminated by hot young stars, creating strange reddish shapes that give the object its nickname. A recent image by ESO's Wide Field Imager (WFI) at the La Silla Observatory (eso1003) captured this visible light view in great detail. NGC 6334 is one of the most active nurseries of massive stars in our galaxy.

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.