Chemists claim metallic hydrogen creation first

Chemistry WorldJon Cartwright

Published in Chemistry World, 14 Nov 2011

For over a century, scientists have said it should be possible to turn hydrogen into a metal. Now, a pair of chemists in Germany claim to have finally performed the feat, although others remain sceptical.

In the late 19th century, chemists pointed out that hydrogen, topping the column of alkali metals in the periodic table, ought to form a metal itself. Physicists Eugene Wigner and Hillard Bell Huntington predicted in 1935 that hydrogen should become a metallic solid at very high pressures – around 25GPa – but experiments later performed at these pressures showed no trace of a metal transition. More recent experiments, reaching pressures above 100GPa and temperatures approaching absolute zero, have offered hints of a metal transition, but generally results have been inconclusive. […]

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How to Tame Lightning

ScienceJon Cartwright

Published in ScienceNOW, 10 Nov 2011

Who at school didn’t like to play with a Van de Graaff generator? Wind it up, put a finger close to the metal shell and—zap!—a spark jolts across the gap. Now imagine the length of that electrical discharge isn’t a few millimeters, but 60 meters. That’s the accomplishment of a team of electrical engineers, which has developed a new way to create electrical discharges, or “arcs.” […]

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Four-wheel nanocar takes to the road

Physics WorldJon Cartwright

Published in Physics World, 9 Nov 2011

A “four-wheel drive car” less than one billionth the length of an average SUV has been built and operated by researchers in the Netherlands and Switzerland. The molecular machine is about 1 nm long and uses electrons as fuel as it navigates across a copper surface. The tiny device could find use in nanometre-sized robotics or as tiny transporters that shift molecules around.

Molecular machines are common in nature. Motor proteins, for example, can move along a surface to transport molecular-sized cargo and are often used to build structures within living cells. Scientists would like to make their own versions of motor proteins, and indeed they have already designed and demonstrated single molecules that can move across surfaces. But these have been mostly passive: to ensure that they travel in a certain direction, they have had to be pulled or pushed. […]

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Plasmonic absorbers turn a corner

Physics WorldJon Cartwright

Published in Physics World, 9 Nov 2011

A new nanostructure that can absorb light at any polarization and across the entire visible spectrum has been made by physicists in the US. The “plasmonic” structure has been used to convert absorbed light into heat and might be able to improve the efficiency of solar cells.

Solar cells may be a tempting green-energy technology, but they remain much less cost-effective than fossil-fuel energy. Most of the high cost of solar cells resides in the production cost of silicon – the most commonly used semiconductor. For this reason, industry is interested in solar cells made of far thinner films – around 1 µm, rather than 300 µm – so that less material is required. […]

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For Newton, a right Hooke

Physics WorldJon Cartwright

Published in Physics World, 8 Nov 2011

Hanging Hooke
Dir. Siobhán Nicholas and Chris Barnes
The Royal Society, 2 October 2011

Shortly after lunchtime on Wednesday 26 June 1689, Robert Hooke began delivering one of his regular lectures at the Royal Society, London. These were dramatic performances in which he would entertain his philosophically minded peers with experiments, often using instruments he had developed himself. But in this lecture, Hooke digressed. “Many of those things I here first discovered could not find acceptance,” he protested. “Yet I find there are not wanting some who pride themselves in arrogating of them for their own.”

Quite how many developments in science and engineering should be credited to Hooke rather than to his contemporaries – especially Isaac Newton – had long been a matter of debate. Then, in 2006, a stash of mysterious papers turned up at a Hampshire country house that threw new light on the subject. They turned out to be Hooke’s long lost Folio – the minutes of meetings at the Royal Society during his tenure as curator of experiments. The Folio revealed that, as Hooke had always maintained, it was he and not the Dutch astronomer Christiaan Huygens who was the first to demonstrate a portable timepiece based on a balance spring. More importantly, it showed that Hooke was first to state that gravity causes the elliptical motion of the planets – an idea that Newton later honed into the famous inverse-square law. […]

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Organic LEDs set to become displays’ flexible friend

Chemistry WorldJon Cartwright

Published in Chemistry World, 31 Oct 2011

Researchers in Canada have created organic light-emitting diodes (OLEDs) on flexible plastic substrates that retain the high efficiency of their non-flexible counterparts. The advance could help OLEDs make the leap into flexible displays.

OLEDs have several advantages over their inorganic counterparts. Unlike normal LEDs, for instance, OLEDs do no not contain toxic heavy metals, such as arsenic, which have been banned in many jurisdictions. Another advantage is that OLEDs are amorphous: they can be made into a variety of different shapes and forms. The most promising are designs on flexible plastic, which can be used to make roll-up computer displays or light-emitting wallpaper. […]

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Complex organic matter may have been found beyond the Solar System

Chemistry WorldJon Cartwright

Published in Chemistry World, 26 Oct 2011

Scientists in Hong Kong believe they have found traces of organic compounds deep in interstellar space that have similar structures to coal and oil. The findings – which are based on infrared spectroscopic data – suggest that these organic compounds exist throughout the universe, and may have seeded life on Earth.

For decades astronomers have been aware of a band of mid-infrared emissions coming from interstellar space, but haven’t been certain of its origin. Many believe the emissions arise from polycyclic aromatic hydrocarbons (PAH) that are excited by ultraviolet photons. Others claim that there are flaws with this hypothesis. These scientists argue that the infrared emissions exist even around cool stars where there is no stimulating ultraviolet radiation, and – perhaps more significantly – that in interstellar environments no individual PAHs have ever been identified. […]

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Mixed solvents exfoliate graphene analogues

Chemistry WorldJon Cartwright

Published in Chemistry World, 4 Oct 2011

Chemists in China have used a mixture of solvents to exfoliate inorganic graphene analogues – two-dimensional nanostructures – from their parent material. The advance could to manufacture inorganic graphene analogues for novel electronic devices.

Inorganic graphene analogues (IGAs) were first discovered by physicists Andre Geim and Konstantin Novoselov of the University of Manchester, UK, in 2005, a year after the same pair discovered graphene. Like graphene, IGAs are single sheets of atoms, bonded in a ‘chicken-wire’ hexagonal structure, with high mechanical strength and flexibility. But although IGAs are less stable at higher temperatures compared with graphene, they do have some particular advantages: for instance, they can act like doped semiconductors without actually adding any dopants. […]

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How to spot a multiverse

Physics WorldJon Cartwright

Published in Physics World, 4 October 2011

How can we tell if another universe has collided with our own? Physicists in Canada and the US believe they have the answer – it would leave “a unique and highly characteristic” imprint in the microwave background that pervades the cosmos. The physicists claim that the prediction can be tested using existing and future space telescopes, which contradicts a widespread view that the existence of a multiverse is untestable.

Chuck Bennett, an astrophysicist at Johns Hopkins University in Maryland, US, who was not involved with the study, believes the prediction helps bring multiverse theory into the realms of conventional, falsifiable science. “Science relies on being able to falsify ideas through experiment or observations of nature,” he says. “The fact that these potentialities exist enables us to call this ‘science’. That, to me, is a significant statement.” […]

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Messenger sheds light on Mercury’s formation

Chemistry WorldJon Cartwright

Published in Chemistry World, 30 Sep 2011

Nasa’s Messenger spacecraft is bringing new understanding to the question of how Mercury formed. The new information looks set to rewrite theories about the birth of the solar system’s smallest planet.

Many scientists consider Mercury – with its high density composition, heavily cratered surface and magnetic field – to be the most unusual planet. It is the smallest of the other three rocky planets – Mars, Venus and Earth – yet it has a massive iron core and only a thin mantle. Scientists had thought these unusual features might have been remnants of a particularly violent formation. […]

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