Accelerator results on cloud nucleation (2)

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Did you get the message?

I’m not sure that the significance of my 15 May post, about the accelerator experiment in Aarhus, has been fully grasped. Following my 13 May post, the blogosphere seems to be still in a “waiting for CLOUD” mode. Yes, it will indeed be fascinating to see the first results from CERN’s CLOUD experiment in two or three months’ time, but meanwhile we have the results from Denmark. Perhaps I was negligent in not giving a little history.

The first laboratory test of the Svensmark hypothesis was the SKY experiment in Copenhagen, the outcome of which was published by the Royal Society of London in 2007. The positive results were of course politically incorrect, because Henrik Svensmark’s discovery of the effect of cosmic rays on clouds gave the Sun a much larger role in climate change than supporters of the man-made global warming hypothesis would like to admit.

The warmists were offered a delaying tactic by physicists who said, “Ah, but the SKY people used only natural cosmic rays and radioactive sources. Don’t believe them unless the CLOUD experiment in Geneva, simulating the cosmic rays with a fully controllable beam of accelerated particles, gets similar results.”

Conveniently for the warmists, CLOUD was very slow to get going. Meanwhile the Danes continued with their own experiments, including the one using an accelerator at Aarhus, as reported in Geophysical Research Letters a few days ago. The most important points are:

• The effect of cosmic rays in helping to seed cloud formation is verified with a particle accelerator, just as critics of SKY were demanding four years ago.
• A simple radioactive gamma-ray source gave just the same results in the Aarhus set-up so the earlier insistence, that only an accelerator experiment would do, was unwarranted.

Nevertheless, let’s say good luck to the CLOUD team. Their big chamber should be able to trace the growth of aerosol seeds much farther than in the small chamber used at Aarhus. And they have a large programme of future work, simulating atmospheric conditions at different altitudes.

See the Aarhus University press release that came out yesterday evening: http://science.au.dk/en/news-and-events/news-article/artikel/forskere-fra-au-og-dtu-viser-at-partikler-fra-rummet-skaber-skydaekke/

For references and other links, see my previous post: https://calderup.wordpress.com/2011/05/15/accelerator-results-on-cloud-nucleation/

For a video interview with Jasper Kirkby of CLOUD see: http://physicsworld.com/cws/article/multimedia/45950

Added 18 May: Ah, now the word is spreading. See

Anthony Watts: http://wattsupwiththat.com/2011/05/17/new-study-links-cosmic-rays-to-aerosolscloud-formation-via-solar-magnetic-activity-modulation/

David Whitehouse: http://thegwpf.org/the-observatory/3016-new-evidence-that-cosmic-rays-seed-clouds.html

The second item quotes me directly, and at the end of the second paragraph I should really have said ionizing “gamma rays” instead of “particles” — I amended it on this blog a few hours after posting it.

Added 20 May: Friendly words from The Scientific Alliance

http://us2.campaign-archive1.com/?u=f1e3eeb023e7d88eff0dda8a2&id=ed0b77bcc3&e=ac788faa66

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Ceramic superconductors disappoint

Predictions revisited

Why ceramic superconductors are disappointing

Helping to explain one of the biggest let-downs of 20th Century technology is a report from a US-European team centred at the University of Florida. It was released yesterday online by Nature Physics. Any scientifically minded person over 35 may remember the huge excitement about ceramic superconductors in 1987. For example, Time magazine called them “a discovery that could change the world” and continued:

That discovery, most scientists believe, could lead to incredible savings in energy; trains that speed across the countryside at hundreds of miles per hour on a cushion of magnetism; practical electric cars; powerful, yet smaller computers and particle accelerators; safer reactors operating on nuclear fusion rather than fission and a host of other rewards still undreamed of. There might even be benefits for the Strategic Defense Initiative, which could draw on efficient, superconductor power sources for its space-based weapons.

“Most scientists believe.” Now where have we heard that before?

Writing in Scientific Europe (1990), Ian Corbett of the UK’s Rutherford Appleton Lab summarized the ceramics story, but much more cautiously.

Sensational events are rare in materials science, but superconducting ceramics attracted media attention of a kind normally reserved for football cup finals. In a heady year that followed their discovery in 1986, even respected newspapers implied that our lives were going to be revolutionized overnight, and that an instant fortune awaited anyone who was quick off the mark in exploiting the new superconductors commercially. Such exaggerated expectations were soon damped down by the reality of the technical problems still be overcome.

The scientific breakthrough was real enough. The phenomenon of superconductivity, in which a material loses all resistance to the flow of an electric current, was previously known only in certain metals and alloys, and at temperatures below -250 ^oC, close to absolute zero. A wholly new class of superconductors opens the way to higher operating temperatures and presumably to wider applications in the electrical and electronic ind ustries.

Georg Bednorz (left) and Alex Muller. Image AIP

In the autumn of 1987 one of the fastest Nobel Prizes ever was awarded to Georg Bednorz and Alex Muller of IBM’s Research Laboratories at Ruschlikon near Zurich – just a year after the first publication, in Zeitschrift für Physik, of their observation of apparent superconductivity in a ceramic material, lanthanum-barium-copper oxide, and at a somewhat higher temperature than any previously authenticated in other materials.

The promise of new applications remains, but unless another unexpected discovery changes the prospects, the road ahead appears at the time of writing to be long and stony.