Mars’ polar ice caps are slowly melting.

The martian ice caps are shrinking. As they are made mostly of frozen carbon dioxide, this evaporation could trigger an increase in Mars’ own greenhouse effect.

Images from the Mars Global Surveyor spacecraft show that ice ridges and escarpments have retreated over the past two years or so. The orbiting probe has also captured the ice thickening and thinning with the passing seasons.

The reason for the change is not yet clea

In any computer’s hard drive, magnetic fields spin electrons this way or that. Now physicists have demonstrated that an electric field can do the same when applied to electrons in semiconductors. And unlike the older magnetic approach, their new device, called a spin gate, is capable of easily imparting a range of spin values. The team’s results, described in a report appearing today in the journal Nature, may one day help to scientists realize the ideal of spintronics—quantum computing based on ele

Astronomers from the University of Pennsylvania, in collaboration with an international team of researchers, have made the first direct detection and measurement of the properties of a dark matter object in the Milky Way.
This observation of a gravitational microlensing event — a temporary increase in the brightness of a background star during the time it takes dark matter to pass in front of it — is reported in today’s issue of Nature.

“By measuring its mass, distance and velocity, w

Bacteria give skin cells their marching orders.

Bacteria that cause potentially lethal ’flesh-eating’ infections make their entrance by telling skin cells to step aside. The bugs hijack the body’s signal for skin cells to become mobile.

Group A streptococci (GAS) normally infect the surface lining of the throat. But occasionally they penetrate skin or the tissues lining the airways, invading deep into the body and causing life-threatening disease.

Finding out how s

A new material helps to make clean fuel from water.

Scientists in Japan have found a more efficient way to extract hydrogen, the ultimate ’green’ fuel, from water. They have developed a material that uses sunlight to break water molecules into their constituent elements of hydrogen and oxygen 1 .

The material is not yet efficient enough to be commercially viable, but its inventors believe that it can be improved. If they are right, hydrogen may soon be on tap

Dental diary of a teenage hominid aged 1.5 million years.

Our early ancestors never went through the awkward age, suggests a new analysis of dental records. Extended youth may have emerged relatively late in human evolution.

Although apes cut the apron strings at around 12 years, despairing human parents are well aware that their kids take at least 18 years to grow up. The development of this prolonged growth period is seen as a key event in human evolution, allowing extra ti