JON CARTWRIGHT – Page 51 – & THREE QUARKS EDITORIAL

NASA’s airborne division

Sky at NightJon Cartwright16 November, 2010

Published in Sky At Night, 16 Nov 2010

Neither a space telescope nor a ground-based observatory, SOFIA is a compromise that could be one of astronomy’s most useful tools

It seemed like a good idea at the time: a modified jumbo jet that could fly non-stop, a quarter of the way around the world from New York to Tokyo, filled with passengers. But when Boeing’s 747SP (special performance) airliner went into production in the mid-’70s, it didn’t do as well as the company had hoped. Rising fuel prices, not to mention a hefty price tag, meant that only a few dozen of the planes were ever produced.

Too bad for Boeing. Yet for a team of researchers at NASA some two decades later, a grounded 747SP was an attractive bargain. Aside from the airliner’s extended flight range, it had an unusually short, fat body – fat enough to house a telescope the size of a hot tub. “The widest body gets you the widest diameter telescope,” says Dana Blackman, a spokesperson for the Stratospheric Observatory for Infrared Astronomy (SOFIA), a joint project between NASA and the German space agency DLR. […]

To read the rest of this article, please contact Jon Cartwright for a copy.

Space–time invisibility cloak could ‘edit history’

Physics WorldJon Cartwright16 November, 2010

Published in Physics World, 16 Nov 2010

Physicists in the UK have proposed a “space–time” invisibility cloak that, if built, could be used to prevent signal interference or give the illusion of a Star Trek teleportation device.

The idea comes after four years of research by different groups that are creating devices to make objects invisible. In 2006 researchers at Duke University in the US created the first device that could cloak a small object in two dimensions in the microwave region of the electromagnetic spectrum. Last year groups at Cornell University and the University of California at Berkeley, US, independently created 2D cloaks that operated at optical wavelengths. Then, earlier this year, a team at the Karlsruhe Institute of Technology in Germany went one step further to produce a 3D optical cloak. […]

The rest of this article is available here.

Feat of clay

New ScientistJon Cartwright10 November, 2010

Published in New Scientist, 10 Nov 2010

The stuff of pottery and piggy banks can be transformed into a material stronger than steel but as light as plastic. Jon Cartwright reports

Julian Evans leans back on his chair in the chemistry department of University College London. For the past hour or so we have been discussing a new wonder material, and now it’s time for me to see it for myself. He shows me a close-up picture of a sample. It looks like the plastic wrapping on a pack of supermarket fruit. “It’s see-through,” I observe, surprised.

Lots of materials are transparent, of course, but they are rarely noted for their strength. Yet this stuff is stronger than steel, and perhaps even a match for Kevlar, the material used in bulletproof vests. It’s also as light as plastic yet as stiff as carbon fibre.

Perhaps the most surprising thing is that it is made from clay – the same stuff we use to make bricks and crockery and which sticks to your spade as you dig your garden. But treated in the right way, clay’s properties can be transformed. It is also dirt cheap. “All you need is to pull it out of the ground and wash it,” Evans says. […]

The rest of this article is available here.

Neutral positronium scatters like a charged particle

Physics WorldJon Cartwright5 November, 2010

Published in Physics World, 5 Nov 2010

Positronium is the atom-like bound state of an electron and its antiparticle the positron – and therefore has no net electrical charge. But physicists in the UK are scratching their heads after finding that positronium interacts with matter as if it were a lone electron, with the mass and positive charge of the positron seemingly invisible. This surprising discovery will spur researchers to find an explanation, and may have consequences from medicine to astrophysics. […]

The rest of this article is available here.

‘Best evidence yet’ for dark matter comes from Milky Way centre

Physics WorldJon Cartwright29 October, 2010

Published in Physics World, 29 Oct 2010

Energetic radiation pulsing from the belly of the Milky Way is the clearest signal yet of dark matter. That is according to a pair of astrophysicists in the US who reach this conclusion after scrutinising the public data collected by NASA’s orbiting Fermi Observatory. “I certainly think it’s the best evidence we’ve seen so far,” says Dan Hooper, one half of the team, based at the University of Chicago.

It is a huge claim because for over 70 years astrophysicists have debated the existence of dark matter, which is thought to make up 80% of the universe’s mass, yet they have failed to gather any definitive evidence, either direct or indirect, for its existence. But with several hints for dark matter published in recent years – all received with scrutiny by the wider astrophysics community – the US pair will have a hard time convincing others that their signal is what they think it is. […]

The rest of this article is available here.

Analogue Hawking radiation spotted in the lab

Physics WorldJon Cartwright22 October, 2010

Published in Physics World, 22 Oct 2010

It was one of Stephen Hawking’s finest insights: the 1974 prediction that black holes are not totally black, but emit a steady stream of radiation. Experimental confirmation of Hawking radiation would probably bring the 68 year-old British cosmologist a Nobel Prize in Physics. Unfortunately, no-one has been able to detect a black-hole signal because it would be so faint compared with the universe’s background radiation.

However, Hawking’s chances at a Nobel may be rising, thanks to a paper that will soon be published in the journal Physical Review Letters. In this work, Italian physicists describe what many believe to be the first measurement of Hawking radiation from a black hole “analogue” in the lab. […]

The rest of this article is available here.

Flexible LEDs to boost biomedicine

NatureJon Cartwright17 October, 2010

Published in Nature, 17 Oct 2010

Bendy, stretchy and bio-compatible arrays of light-emitting diodes (LEDs) and photodetectors that can be implanted under the skin are boosting prospects of using light inside the body to activate drugs or monitor medical conditions.

The materials were made by John Rogers at the University of Illinois at Urbana-Champaign and his colleagues, who describe applications of their work today in Nature Materials. […]

The rest of this article is available here.

Organic solar cells receive a boost

Physics WorldJon Cartwright15 October, 2010

Published in Physics World, 15 Oct 2010

Physicists in the US have shown that organic semiconductors may be just as promising as their inorganic counterparts in solar cells. The researchers’ discovery – that bound electron–hole pairs can travel a thousand times farther in organic semiconductors than previously observed – suggests that organic solar cells could one day be made efficient, cheap and in high volume.

Today, commercial solar cells are made of inorganic semiconductors such as silicon. When a photon in the visible or near-infrared part of the light spectrum strikes the surface of the cell, it generates an electron–hole pair, which quickly disassociates. It is effectively the separation of such electrons and holes in the semiconductor that creates a voltage, so that a current can flow. […]

The rest of this article is available here.

An everlasting read

Sky at NightJon Cartwright29 September, 2010

Published in Sky at Night, 1 Oct 2010

Cycles of Time

Roger Penrose

The Bodley Head (Random House), 288pp

Currently emeritus Rouse Ball Professor of Mathematics at the University of Oxford, and perhaps best known for his work on black holes with Stephen Hawking, Sir Roger Penrose is without doubt a very clever man.

Yet if one can fault Penrose’s brain, it is that he doesn’t realise everyone else is not so clever. In his first “popular science” book, The Emperor’s New Mind (1989), a work that explored the nature of consciousness, he casually slipped in a few entire pages of binary code for the “enterprising reader” to decipher. In his last great tome, The Road to Reality (2005), he attempted to explain all the laws of the universe in a mere 1,136 pages. It seems likely a vast portion of readers never finished his past books, and the same, sadly, will probably happen with his latest. (more…)

Relativity comes down to Earth

NatureJon Cartwright23 September, 2010

Published in Nature, 23 Sep 2010

Albert Einstein’s theories of relativity, which predict that relative speed and gravity affect the passing of time, have never been easy to bring home to the general public. In the early 1970s, scientists demonstrated relativity by putting synchronized atomic clocks on jumbo jets that flew eastwards and westwards around Earth. The westbound plane — the one flying against Earth’s rotation — gained time compared with a fixed reference clock on the ground. But this wasn’t exactly an everyday scenario.

Chin-wen Chou and his colleagues at the National Institute of Standards and Technology (NIST) in Boulder, Colorado, have now demonstrated Einstein’s theories on more mundane scales. In tests of the special and general theories of relativity, the NIST researchers show that time speeds up if you climb just one rung up a ladder, and slows down if you travel at just 36 kilometres per hour. Their results are reported in Science this week. […]

The rest of this article is available here.