Tiny single-cell organisms discovered living underground could help dispose off hazardous nuclear waste, scientists say.

Although bacteria with waste-eating properties have been discovered in relatively pristine soils before, this is the first time that microbes that can survive in the very harsh conditions expected in radioactive waste disposal sites have been found.

The disposal of nuclear waste is very challenging, with very large volumes destined for burial deep underground.

The largest volume of radioactive waste, termed 'intermediate level', will be encased in concrete prior to disposal into underground vaults, researchers said.

When ground waters eventually reach these waste materials, they will react with the cement and become highly alkaline.

This change drives a series of chemical reactions, triggering the breakdown of the various 'cellulose' based materials that are present in these complex wastes.

One such product linked to these activities, isosaccharinic acid (ISA), causes much concern as it can react with a wide range of radionuclides - unstable and toxic elements that are formed during the production of nuclear power and make up the radioactive component of nuclear waste.

In an experiment on fruit flies, UCLA biologists activated just one gene, AMPK, which extended their lifespan by nearly a third, by helping them to get rid of "cellular garbage" causing old age diseases such as Parkinson's. Humans have the same gene.

"Instead of studying the diseases of aging - Parkinson's disease, Alzheimer's disease, cancer, stroke, cardiovascular disease, diabetes - one by one, we believe it may be possible to intervene in the aging process and delay the onset of many of these diseases," said author David Walker, an associate professor of integrative biology and physiology at UCLA, whose paper was published last week in the scientific journal Cell Reports.

"We are not there yet, and it could, of course, take many years, but that is our goal and we think it is realistic."

UCLA's laboratory conducted the study on 100,000 fruit flies, used because they have been genetically mapped, and scientists can easily mutate just one gene within a population, limiting variables, and ensuring a perfectly controlled experiment.

Those flies with the gene activated in their intestines lived just over eight weeks, instead of the usual six, and, almost as crucially, remained healthier for longer into their lifespans. Projected onto the current US life expectancy of 78, this would correspond to an average lifetime of 101 years.

A new study published in The Journal of Geology provides support for the theory that a cosmic impact event over North America some 13,000 years ago caused a major period of climate change known as the Younger Dryas stadial, or "Big Freeze."

Around 12,800 years ago, a sudden, catastrophic event plunged much of the Earth into a period of cold climatic conditions and drought. This drastic climate change - the Younger Dryas - coincided with the extinction of Pleistocene megafauna, such as the saber-tooth cats and the mastodon, and resulted in major declines in prehistoric human populations, including the termination of the Clovis culture.

With limited evidence, several rival theories have been proposed about the event that sparked this period, such as a collapse of the North American ice sheets, a major volcanic eruption, or a solar flare.

However, in a study published in The Journal of Geology, an international group of scientists analyzing existing and new evidence have determined a cosmic impact event, such as a comet or meteorite, to be the only plausible hypothesis to explain all the unusual occurrences at the onset of the Younger Dryas period.

In electronics, changing the path of electrons and manipulating how they flow is as easy as applying a magnetic field.

Not so for light. "We don't have such a thing for light," said Michal Lipson, professor of electrical and computer engineering. "For the majority of materials, there is no such thing as something I can turn on, and apply this magic field to change the path of light."

Until now. Lipson, a leader in the emerging field of silicon photonics - sending light through waveguides instead of currents through wires - and colleagues have shown that an equivalent field for light does exist. Experiments led by graduate student Lawrence Tzuang, in collaboration with Paulo Nussenzveig of University of Sao Paulo and Kejie Fang and Shanhui Fan from Stanford University, are described in a recent issue of Nature Photonics.

This effective magnetic field has to do with the light's phase, which is a measure of a particular point in a light wave's cycle, quantified as an angle in degrees.

A powerful solar flare sparked on an Earth-facing section of the sun. A subsequent coronal mass ejection is expected to reach our planet later in the week, possibly causing disruptions of communication and power grids.

The flare was unleashed by the sun on Wednesday and was estimated at X1.6, putting it in the strongest 'extreme' class of solar flares. It was launched from a sunspot called Active Region 2158 and was caught on camera by NASA's Solar Dynamics Observatory spacecraft, reports Space.com. The same region produced a smaller flare a day before that.

The flare was accompanied by the release of superhot plasma, a coronal mass ejection, with the cloud expected to reach Earth later on Friday. Luckily, most of it is expected to pass north of Earth, causing a relatively week solar storm. Power grids may experience some fluctuations, as the plasma would affect the planetary magnetic field, but it poses little danger either to anyone down here or to crew members of the International Space Station.

Humans are killing off species thousands of times faster than nature creates them, new research finds.

The modern rate of extinction across species is 1,000 times that of the background rate before humans began altering the globe and thousands of times faster than the creation of new species, according to a new study in the journal Conservation Biology. The findings echo and expand on previous research published in the journal Science, which also suggested that humans are on the verge of causing a sixth mass extinction on Earth.

"We now know for certain how much faster species are going extinct," said Stuart Pimm, a conservation ecologist at Duke University and president of the nonprofit conservation group Saving Species.

The latest in robotic design is leading to 'new creatures' that can move without constraint, withstand harsh temperature changes, ambulate over a variety of surfaces and even 'limbo'. The newest model has recently been let off the leash.

The latest 'soft' robot from Professor George M. Whitesides Research Group at Harvard uses embedded pneumatic networks that enable movement by pressurizing particular channels.

The work is possible because of collaborations happening across the sciences combining organic chemistry, soft materials science and robotics.

Astronomers using NASA's Hubble Space Telescope have discovered a companion star to a rare type of supernova. This observation confirms the theory that the explosion originated in a double-star system where one star fueled the mass-loss from the aging primary star.

This detection is the first time astronomers have been able to put constraints on the properties of the companion star in an unusual class of supernova called Type IIb. They were able to estimate the surviving star's luminosity and mass, which provide insight into the conditions that preceded the explosion.

"A binary system is likely required to lose the majority of the primary star's hydrogen envelope prior to the explosion.

The problem is that, to date, direct observations of the predicted binary companion star have been difficult to obtain since it is so faint relative to the supernova itself," said lead researcher Ori Fox of the University of California (UC) at Berkeley.

Astronomers estimate that a supernova goes off once every second somewhere in the universe. Yet they don't fully understand how stars explode. Finding a "smoking gun" companion star provides important new clues to the variety of supernovae in the universe. "This is like a crime scene, and we finally identified the robber," quipped team member Alex Filippenko, professor of astronomy at UC Berkeley. "The companion star stole a bunch of hydrogen before the primary star exploded."

The explosion happened in the galaxy M81, which is about 11 million light-years away from Earth in the direction of the constellation Ursa Major (the Great Bear). Light from the supernova was first detected in 1993, and the object was designated SN 1993J. It was the nearest known example of this type of supernova, called a Type IIb, due to the specific characteristics of the explosion. For the past two decades astronomers have been searching for the suspected companion, thought to be lost in the glare of the residual glow from the explosion.

A long-standing theory that excessive conflict is bad for society has been demonstrated in an animal population, researchers report.

Aggressive and peaceful Gouldian finches can live together as long as the aggressors are not too successful, suggest the findings which are based on game theory.

The research is published today in the Proceedings of the Royal Society B.

Game theory is a branch of mathematics used to model the effects of different strategies through a series of games. It's widely used in economics. In the 1970s it was applied to biology in the form of the 'hawk-dove game' to explain why it is that animals don't fight all the time.

In this game, 'hawks' have a strategy of aggression while 'doves' have a more peaceful strategy. According to the theory, overall conflict is minimised because while hawks fight for a resource, doves backs down and let them have it.

"It means those individuals are avoiding conflict and that's good for both of them," says Associate Professor Simon Griffith, an evolutionary biologist at Macquarie University.

While this is an advantage to an individual hawk it may backfire in the long term. This is because hawks are generally too busy wearing themselves out fighting to look after themselves or the next generation.

"There is a trade off between how much time you spend fighting and how much time you spend at your nest looking after your chicks," says Griffith.

According to the hawk-dove theory, there is an optimal ratio of hawks to doves that allows for the fact that hawks aren't good at rearing chicks.

We often view the solar system as constant and unchanging, at least over human time scales. This, of course, is not entirely accurate and astronomers have detected a surprisingly rapid phenomenon inside one of Saturn's rings: moonlets the size of mountains are created and destroyed over a matter of days or even hours.

This discovery centers around the gas giant's F-ring where, over the course of 30 years, has dramatically changed its morphology.

"The F ring is a narrow, lumpy feature made entirely of water ice that lies just outside the broad, luminous rings A, B, and C," said Robert French of the SETI Institute, at Mountain View, Calif., in a news release "It has bright spots. But it has fundamentally changed its appearance since the time of Voyager. Today, there are fewer of the very bright lumps."

French and co-investigator Mark Showalter (also from the SETI Institute) studied photographs of the F-ring taken by NASA's twin Voyager spacecraft when they encountered the ringed planet in the early 1980s.

On comparison with photographs from NASA's Cassini spacecraft that is currently in orbit around Saturn, the F-ring has changed appearance extensively.

Further investigations revealed that bright lumps in the ring come and go over periods of only hours or days - features that the researchers believe are small moons.