A cool shirt

IF A room is cold, you have a choice. Pull on a jumper or a jacket, or turn up the heating. If it is hot, the obverse choice is not so easy to make. There is a limit to how much disrobing is permissible, and even the wearing of light garments such as T-shirts, in order to stay cool, is frowned on in some business circles. The default is therefore to switch on the air conditioning.

That may change if a discovery published this week in Science comes to commercial fruition. Yi Cui and his colleagues at Stanford University have discovered a fabric that keeps skin 2°C cooler than a cotton T-shirt. In terms of comfort, this is a significant drop—and one which would be good not only for the wearer but also for energy bills. If widely adopted it would mean buildings could be kept warmer than at present, saving huge amounts of electricity in the summer months.

Dr Cui’s goal was to cool the wearers of clothing by tinkering with the way heat radiates from their bodies. More than half of body heat is in the infrared (IR) part of the spectrum. This means its wavelength is longer than that of visible light. Materials like…Continue reading
Source: Economist

Dawn of a new epoch?

The start of something new

ONE way to think of science is as a series of painful demotions. In the 1500s Nicolaus Copernicus kicked Earth from its perch at the centre of the universe. Later, Charles Darwin showed that humans are just another species of animal. In the 20th century geologists found that all human history amounts to less than an eye-blink in the span of a planet that they discovered is 4.6 billion years old.

Now, though, those geologists’ spiritual descendants may give humans an unexpected promotion—to the status of geological movers and shakers. On August 29th Colin Waters, the secretary of the Anthropocene Working Group (AWG), an ad hoc collection of geologists, addressed the International Geological Congress in Cape Town. He told his colleagues that there was a good case for ringing down the curtain on the Holocene—the present geological epoch, which has lasted for 12,000 years—and recognising that Earth has entered a new one, the Anthropocene.

As its name suggests, the point of this new epoch would be to acknowledge that humans, far from being mere passengers on the planet’s…Continue reading
Source: Economist

The Countess of Computers

Source: Economist

Round and round the mulberry bush

A PLANET orbiting a star tugs it gently this way and that, so it oscillates between moving towards Earth and away from it. The velocities involved are tiny: for Proxima Centauri about two metres per second, a brisk walk. Nevertheless, the effect on the star’s spectrum can be measured from the ground. When a star is approaching Earth, its light is slightly bluer; when away, slightly redder. For this method, the plane of the planet’s orbit need not be aligned with Earth.

The transit technique, by contrast, requires that it is, so that the planet passes between Earth and its parent star every orbit. When that happens, the parent star’s light will dim accordingly. Transiting was used with great success by Kepler, an American space telescope which detected well over 1,000 distant planets earlier this decade. Statistical analysis of that sample suggests many—possibly all—red dwarfs have rocky planets, and that they are likely to crop up quite frequently in a red dwarf’s habitable zone. Since red dwarfs are the commonest stars, the most likely place to find an Earthlike planet is in orbit around one.

Source: Economist

Dark arts

SINCE their invention two centuries ago, batteries have been made from many things. The first were of copper and zinc. Today, lithium is preferred for a lot of applications. Lead, nickel, silver and a host of other materials have also been used. Until recently though, no one had tried melanin, the pigment that darkens skin and protects it against ultraviolet light. But, as he reported this week at a meeting of the American Chemical Society in Philadelphia, Christopher Bettinger of Carnegie Mellon University, in Pittsburgh, has now done just that. His purpose is to create a battery safe for use in the human body.

Melanin is not, at first sight, an obvious battery ingredient. It is a complicated molecule composed of carbon, oxygen, nitrogen and hydrogen. To synthesise it on an industrial scale would surely require biotechnology rather than conventional chemistry. But it does have the ability to capture and release positively charged ions, known as cations. Batteries depend on the movement of ions, so this property is a good start. On top of that, being a normal ingredient of bodies, melanin is not toxic. This is in contrast to many conventional battery…Continue reading
Source: Economist

Foul play

Blistering barnacles!

“FOR God’s sake and our country’s,” wrote an 18th-century captain in Britain’s navy to the Admiralty in Whitehall, “send copper bottomed ships to relieve the foul and crippled ones.” Copper sheathing, first deployed widely in the 1780s, kept fouling at bay by inhibiting the growth of barnacles, mussels, tube worms and shipworms (actually a type of clam). But even today, when copper has been replaced by modern antifouling paints and wooden hulls have given way to metal ones, ship-fouling is still a problem.

Dealing with it costs billions of dollars a year and often involves toxic chemicals whose use is being progressively restricted. How the larvae of befouling creatures choose where to settle is thus of great interest. A paper just published in the Proceedings of the National Academy of Sciences by Nick Shikuma of San Diego State University and his colleagues sheds some light.

Dr Shikuma studies tubeworms. These shell-forming annelids have become model organisms for students of ship-fouling. Their research has already shown that tubeworm larvae like to…Continue reading
Source: Economist

Deep waters

The good ship Zhang Jian over the New Britain trench

TO MAN or not to man, that is the question. In the great days of exploration—of deserts and jungles, of the Arctic and Antarctic, even of the Moon, there was no alternative. Now, though, machines can do most of what human beings can accomplish, and frequently more. Yet humanity continues to put men and women in harm’s way when robots would do the job perfectly well.

The latest example comes from China, where a scientific adventurer called Cui Weicheng hopes to reap glory for himself and his country by organising routine manned expeditions to the hadal zone—the deepest part of the ocean, defined as anything below 6,000 metres. Dr Cui is the founder and director of the Hadal Science and Technology Research Centre (HAST) at Shanghai Ocean University. He became a national hero four years ago when Jiaolong, a manned submersible whose construction he organised, successfully plunged 7,062 metres down into the Mariana trench in the western Pacific Ocean. That enrolled China into the small club of countries (other members: America, France, Japan and…Continue reading
Source: Economist

Exploring the final frontier

Source: Economist

Scientists have discovered an Earth-like planet orbiting a nearby star

“WE’VE been wondering what planet we’re first going to look for life on. Now we know.” Rory Barnes, of the University of Washington, puts it nicely. Proxima Centauri, the star closest to the sun, has a planet. That planet weighs more or less the same as Earth and is therefore presumably rocky. And it orbits within its parent star’s habitable zone—meaning that its surface temperature is likely to be between 0°C and 100°C, the freezing and boiling points of water at sea level on Earth.

A prize discovery, then, for astrobiologists such as Dr Barnes. And the discoverers are a transnational team of astronomers who have been using telescopes at the European Southern Observatory (ESO) in the Atacama desert, in Chile, for planet-hunting. Though they have not seen the new planet directly (they have inferred its existence from its effect on its parent star’s light), their paper in Nature describes what they have been able to deduce about it.

Proxima Centauri b, as it is known, probably weighs between 1.3 and three times as much as Earth and orbits its parent star once every 11 days. This puts its distance from Proxima Centauri…Continue reading
Source: Economist

Cutpurse capers

Big Brother really is watching you

SMART-CARD public-transport ticketing systems let people hop between buses, subways, trams, surface rail and river boats—even when these are operated by different companies—without having to buy new tickets. This undoubted good, though, has ramifications. One is that anyone with access can, by following individual passengers (or, at least, their cards), study precisely where people are going.

Companies use this knowledge to optimise services—again, an undoubted good. But many other things, some disturbing to freedom lovers, might also be done with smart-card data. One, outlined in San Francisco this week at the Knowledge Discovery and Data Mining conference, seems completely unsinister on the face of it. This is to use such data to catch pickpockets.

The idea is the brainchild of Xiong Hui of Rutgers University, in New Jersey, and Du Bowen and Hou Zhenshan of Beihang University, in Beijing. Together, they studied the movements of passengers on Beijing’s buses, trains and subways. As might be expected, most moved swiftly from A to B—taking the least time or smallest number…Continue reading
Source: Economist