Whoosh — not missing just busy

23/10/2010

I’m all too aware of the sluggish rate of new posts recently. That’s because of other fascinating and urgent work that I hope you’ll all hear about before too long.

Douglas Adams famously said,  “I love deadlines. I like the whooshing sound they make as they fly by.”

Perhaps I take them too seriously, but it’s a fault that’s done no harm in my work.

Can I suggest to my very welcome visitors that they might like to browse  through the 90-plus existing posts, under Categories?


Hal Lewis quits APS

10/10/2010

Climate Change – News & Comments

Prof. Hal Lewis resigns from the American Physical Society

Going along with Anthony Watts’ suggestion that this should be posted on every science blog, I have merely added a photo,  some emphasis, and some bulleting.

From: Hal Lewis, University of California, Santa Barbara

To: Curtis G. Callan, Jr., Princeton University, President of the American Physical Society

6 October 2010

Dear Curt:

When I first joined the American Physical Society sixty-seven years ago it was much smaller, much gentler, and as yet uncorrupted by the money flood (a threat against which Dwight Eisenhower warned a half-century ago).

Indeed, the choice of physics as a profession was then a guarantor of a life of poverty and abstinence—it was World War II that changed all that. The prospect of worldly gain drove few physicists. As recently as thirty-five years ago, when I chaired the first APS study of a contentious social/scientific issue, The Reactor Safety Study, though there were zealots aplenty on the outside there was no hint of inordinate pressure on us as physicists. We were therefore able to produce what I believe was and is an honest appraisal of the situation at that time. We were further enabled by the presence of an oversight committee consisting of Pief Panofsky, Vicki Weisskopf, and Hans Bethe, all towering physicists beyond reproach. I was proud of what we did in a charged atmosphere. In the end the oversight committee, in its report to the APS President, noted the complete independence in which we did the job, and predicted that the report would be attacked from both sides. What greater tribute could there be?

How different it is now. The giants no longer walk the earth, and the money flood has become the raison d’être of much physics research, the vital sustenance of much more, and it provides the support for untold numbers of professional jobs. For reasons that will soon become clear my former pride at being an APS Fellow all these years has been turned into shame, and I am forced, with no pleasure at all, to offer you my resignation from the Society.

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Sun cools? How daft!

07/10/2010

Climate Change – News and Comments

An active Sun cools the world? How daft!

Valiant efforts of British physicists to deny that the Sun is important in climate change have always been good for a laugh. Names like Mike Lockwood and Arnold Wolfendale spring to mind. But with what she’s published in today’s Nature a professor at Imperial College London, Joanna Haigh, wins the my Gag of the Year prize.

The 200-year-old problem for solar-terrestrial physicists is to explain why the historical record shows strong and persistent links between solar activity and climate change over decades, centuries and millennia. Variations in visible light won’t do the job. The only mechanism powerful enough is Svensmark’s hypothesis about cosmic rays governing low cloud cover – see https://calderup.wordpress.com/category/3b-the-svensmark-hypothesis/ .

Haigh has never gone along with Svensmark, preferring instead to focus on ultraviolet light from the Sun, which does vary more than the visible light, and generally to minimize solar effects on climate. But in her new paper she offers to tear everything up and scatter it to the wind, because a satellite measured an increase in the intensity of visible light between 2004 and 2007, when solar activity was in decline. From the paper:

Daily measurements of the solar spectrum between 0.2 mm and 2.4 mm, made by the Spectral Irradiance Monitor (SIM) instrument on the Solar Radiation and Climate Experiment (SORCE) satellite3 since April 2004, have revealed that over this declining phase of the solar cycle there was a four to six times larger decline in ultraviolet than would have been predicted on the basis of our previous understanding. This reduction was partially compensated in the total solar output by an increase in radiation at visible wavelengths.

As summarized in an ICL press release:

The researchers used satellite data and computer modelling to analyse how the spectrum of radiation and the amount of energy from the Sun has been changing since 2004. Instruments on the SORCE satellite have been measuring the Sun’s energy output at many different wavelengths. The researchers fed the data from SORCE into an existing computer model of the Earth’s atmosphere and compared their results with the results obtained using earlier, less comprehensive, data on the solar spectrum.

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With graphene, carbon scores again

05/10/2010

Updating Magic Universe

With graphene, magical carbon scores again

Today’s award of the physics Nobel Prize to Andre Geim and Konstantin Novoselov “for groundbreaking experiments regarding the two-dimensional material graphene” gives me the chance to update what I wrote about carbon honeycombs in Magic Universe, which was published a year before the graphene story broke in 2004.

In an earlier post I’ve rhapsodised about polycyclic aromatic hydrocarbons in the cosmos, and their relevance to the origin of life – see https://calderup.wordpress.com/2010/06/01/comets-and-life-2-2/ — but now it’s the terrestrial side of the carbon saga that makes the mind boggle. We’re talking about the familiar graphite that comes off the end of your pencil when you write, but now reduced to a layer just one atom thick.

The relevant story in Magic Universe is called “Buckyballs and nanotubes: doing very much more with very much less.” Starting with a nod to the geodesic dome designer Buckminster Fuller, who inspired the names of the football-like C60 molecules, fullerenes or buckyballs, found in 1985, it proceeds from that discovery to the molecular basket-work of the carbon nanotubes, first made in 1991. Today’s update belongs after some cheerful speculations that followed.

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Relativity on the human scale

24/09/2010

Updating Einstein’s Universe and Magic Universe

Relativity on the human scale

The most gratifying physics I’ve seen for a while comes in today’s Science magazine, from James Chin-Wen Chou and his colleagues in the Time and Frequency Division at the National Institute of Standards and Technology in Boulder, Colorado. They detect well-known effects of relativity on the rate of time passing, but now on the scale of ordinary human activities.

Standard atomic clocks employ microwaves to ensure their regularity, but Chou’s team used laser light in a pair of aluminium-27 optical clocks (invented in 2005), which gives about 100 times better accuracy. In one experiment, they used an electric field to jiggle the aluminium ion at the heart of a clock and showed that time passed more slowly in accordance Einstein’s Special Relativity theory, about the effect of motion on time. The effect of atomic motion as slow as 8 metres per second (about 30 km/h) was detectable.

Raising a clock makes it run a little faster. Credit: Chou et al., Science, 24 September 2010 – see reference.

Especially pleasing for me was another experiment, in which one clock was jacked up just 33 cm relative to the other. The clock gaining height ran faster because it was further from the Earth’s centre of gravity, and the gravitational field was slightly weaker, in accordance with General Relativity. As the change in clock rate was only about 40 parts in a billion billion (1018), its detection was a tour de force for the NIST team.

This effect of altitude on time was the key to the efforts by Martin Freeth of BBC-TV and me to make Einstein’s theory of gravity, General Relativity, comprehensible to the public, in our film “Einstein’s Universe” (1979).

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Kennelful of Pluto puppies

13/09/2010

Pick of the Pics and Updating Magic Universe

A kennelful of Pluto puppies

Three successive images from the Hubble Space Telescope show two remote objects in the Solar System inching across the sky in front of a distant galaxy (bottom left of each image). The near-vertical streaks are due to the objects moving while Hubble was watching. They are small “trans-Neptunian” objects – comets or asteroids – orbiting the Sun at about 43 times farther out than the Earth. They appear to be companions, at about half the separation of the Earth and Moon. Credits: a negative version of part of Fig. 3 in Fuentes et al., Astrophysical Journal (see references); imagery from HST/ACS/WFC

Soon to be published is the discovery of 14 new members of the Solar System in the so-called Kuiper Belt beyond the most distant “real” planet, Neptune. They are 40-100 km leftover scraps from the building of the Sun’s family of planets. To find them, a team from the Harvard-Smithsonian Center for Astrophysics and Northern Arizona University, led by Carlos Fuentes, trawled through existing images from the Hubble Space Telescope.

As Halley’s Comet and 15 other regular visitors came from the trans-Neptunian Kuiper Belt, I suppose I should be updating my Comets book, but although it mentions “Halley-class” comets orbiting not far beyond Neptune, it doesn’t name the Kuiper Belt. That important feature figures in Magic Universe, which was written two decades later and is more receptive to updating on this point. Here’s the most relevant section in the story called “Comets and asteroids: snowy dirtballs and their rocky cousins”.

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Worse than Ivan the Terrible

06/09/2010

Predictions Revisited

Worse than Ivan the Terrible

The “balance of error” for a missile boat’s captain

Prompting this post is a recent report that Russian Akula-class hunter-killer submarines are stalking British Vanguard-class submarines carrying Trident nuclear missiles. It’s the sort of thing that happened routinely during the Cold War. Thomas Harding, defence editor of the Daily Telegraph, quotes a senior Royal Navy source as saying: “The Russians have been playing games with us, the Americans and French in the North Atlantic. We have put a lot of resources into protecting Trident because we cannot afford by any stretch to let the Russians learn the acoustic profile of one of our bombers as that would compromise the deterrent.”

Bombers, by the way, is Navy slang for missile-carrying boats.

The special problems of controlling them figured in one of the predictions of possible routes to nuclear war explored in 1979 by Peter Batty and me in our BBC-TV programme “Nuclear Nightmares”.

In the accompanying book of the same title I wrote:

… the submarine as the weapon of the last resort remains an important concept and an awkward problem in command and control because, by definition, the submarine ought logically to be able to launch its missiles without receipt of explicit orders.

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Wheat genome

27/08/2010

Updating Magic Universe

The genetic code of wheat

Last night the UK’s Biotechnology and Biological Sciences Research Council made available online a draft of the largest genetic code of an organism ever tackled – the genome of wheat, which is five times larger than the human genome and more than 30 times larger than that of rice, revealed back in 2002. But well worth the effort, for a crop with virtues that have shaped human history since its domestication more than 10,000 years ago.

Spikelet of Chinese Spring wheat, Triticum aestivum. Photo: E.J.M. Kirby

Chinese Spring wheat is the variety now read. Leading the work is the British team of Neil Hall and Anthony Hall at the University of Liverpool, Keith Edwards and Gary Barker at the University of Bristol. and Mike Bevan at the John Innes Centre. Most of the actual gene-reading was done with a “platform” developed in the USA by a subsidiary of Swiss company Roche.

The implications are big. Although the genome isn’t yet organised into its chromosomes, plant breeders now have access to 95 per cent of all wheat genes. That should shorten by some years the time required to develop viable new varieties of wheat that can thrive in marginal conditions – adapted for example to face drought, salty soil, or disease.

Here’s the most relevant extract from the story in Magic Universe called “Cereals: genetic boosts for the most cosseted inhabitants of the planet.”

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Who blew up Jerusalem?

23/08/2010

Predictions Revisited

Who blew up Jerusalem?

A nightmare from the 1970s persists

US Assures Israel That Iran Threat Is Not Imminent” says a headline on a recent New York Times report, available here: http://www.nytimes.com/2010/08/20/world/middleeast/20policy.html . It seems that US intelligence is saying, “Relax, Iran won’t have a nuclear weapon for a year or more.”

For 30 years since the producer Peter Batty and I explored the possible triggers of nuclear war, in our TV blockbuster Nuclear Nightmares: The Wars That Must Never Happen”, a truly depressing number of people have continued to play with fire, in the proliferation of bomb-making technology. The accompanying book, Nuclear Nightmares, quoted an anonymous American strategist calling proliferation “the least unlikely route to nuclear war”. And because Israel was known (in 1979) to have already made nuclear weapons at a plant in the Negev Desert, we set our story in the Middle East.

Each scenario in the programme culminated with a fictional survivor trying to make sense of what happened. Here’s the relevant extract as broadcast.

PRESENTER (Peter Ustinov) on a vantage point above Jerusalem: The holy city of Christians, Jews and Moslems – the order is strictly alphabetical. It has been the focal point for conflict for thousands of years. Jerusalem is at this time in Israeli hands. But you can look North towards the Soviet Union with its Moslem minorities and affiliations. East towards a patchwork of Moslem states, patient yet unforgiving. South towards Mecca, the power of religion and of oil. And West toward America, Israel’s powerful friend.

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Dark matter’s lens

20/08/2010

Updating Magic Universe

Dark matter’s lens on the cosmic scenery

Since 1996 the efforts of the French astrophysicist Jean-Paul Kneib to exploit natural lenses in the sky, created by the dark matter that surrounds clusters of galaxies, have fascinated me. While other stargazers used the “gravitational lenses”, bending light in the Einsteinian manner, to see galaxies far beyond the range of unaided telescopes, Kneib’s aim was to chart the mysterious dark matter itself. He wanted to see how visible matter and the far weightier dark matter have interacted through cosmic time – to see “the whole history of the Universe from start to finish”, as Kneib remarked to me in 2002.

It’s been taxing work, but now Kneib is one of the team reporting in today’s Science magazine about the dark matter around one the richest known clusters of galaxies. Abell 1689 lies 2.2 billion light-years away in the Virgo constellation, and a couple of years ago its extraordinary lensing power revealed a very distant and early object in the sky, Galaxy A1689-zD1, 12.8 billion light-years away. But that’s by the way

The new report not only gauges the cluster’s dark matter but uses the galaxies beyond it to infer the overall nature of space-time itself, dominated by the even more massive dark energy that drives the accelerating expansion of the Universe.

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