The Sun and auroras for beginners


Pick of the pics

Our Explosive Sun by Pål Brekke

In “Our Explosive Sun”, the picture has this caption. “A unique image of the planets close to the Sun observed with the LASCO telescope on SOHO. An occulting disk inside the telescope blocks the bright light from the solar disk creating an artificial solar eclipse. Mercury, Venus, Jupiter, Saturn, and the Pleiades are visible. Just outside the occulting disk one can see enormous ejections of gas from the hidden Sun. The horizontal streaks from the planets are artifacts from the digital camera (ESA/NASA).”

It’s one of my favourite images from the Space Age. The Large Angle and Spectrometric Coronagraph (LASCO) took it on 15 May 2000. Four planets and the Pleiades star cluster were almost in line with the Sun – which chose this theatrical moment to blast off a huge puff of gas in a coronal mass ejection (CME). So I’m not surprised to find the picture in Our Explosive Sun by Pål Brekke, a colourful book that’s just been published by Springer.

Pål Brekke (NRS)

Pål (pronounced Paul) is a Norwegian solar physicist who worked in the SOHO team for more than a decade, latterly as Deputy Project Scientist. We’ve known each other well from the time when I was writing a lot for the European Space Agency. Pål’s now a Senior Advisor at the Norwegian Space Centre.

Let’s be clear that Our Explosive Sun is a book for beginners, be they amateur astronomers, aurora watchers, high school students, or interested non-experts of any description. There’s plenty of elementary information about our mother star and the Solar System, and about how to observe the Sun safely or photograph the Northern Lights. Making the book distinctive are a mass of extraordinarily vivid and up to date illustrations, plus the occasional insights you get only from a true expert.

For example, in warning of the dangers that solar explosions will pose to astronauts flying to the Moon or Mars, Pål reminds us that the lunar flights of Apollos 16 and 17, in April and December 1972, were lucky to miss a big burst of deadly solar protons in August of that year. And in explaining the distances of stars, he notes that in about 40 years time an astronomer with a supertelescope on a planet in the Pleiades star cluster might in principle see Galileo turning his own telescope on the Pleaides for the first time, from a distance of 440 light-years.

It’s a pity perhaps that Pål doesn’t mention cosmic rays, which provide one of the great markers of solar variations both currently and in the past. And his remarks on solar activity and climate change are brief and rather cautious, e.g.: One thousand years ago, it was warmer on Greenland than today. … Human-driven climate change will work in addition to natural climate variability mainly caused by the Sun.


Pål Brekke, Our Explosive Sun: A Visual Feast of Our Source of Light and Life, Springer 2012. [Hardcover]

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CERN experiment confirms cosmic ray action


Climate Change – News and Comments

The global warmists’ dam breaks

A graph they'd prefer you not to notice. Tucked away near the end of online supplementary material, and omitted from the printed CLOUD paper in Nature, it clearly shows how cosmic rays promote the formation of clusters of molecules (“particles”) that in the real atmosphere can grow and seed clouds. In an early-morning experimental run at CERN, starting at 03.45, ultraviolet light began making sulphuric acid molecules in the chamber, while a strong electric field cleansed the air of ions. It also tended to remove molecular clusters made in the neutral environment (n) but some of these accumulated at a low rate. As soon as the electric field was switched off at 04.33, natural cosmic rays (gcr) raining down through the roof of the experimental hall in Geneva helped to build clusters at a higher rate. How do we know they were contributing? Because when, at 04.58, CLOUD simulated stronger cosmic rays with a beam of charged pion particles (ch) from the accelerator, the rate of cluster production became faster still. The various colours are for clusters of different diameters (in nanometres) as recorded by various instruments. The largest (black) took longer to grow than the smallest (blue). This is Fig. S2c from supplementary online material for J. Kirkby et al., Nature, 476, 429-433, © Nature 2011

Long-anticipated results of the CLOUD experiment at CERN in Geneva appear in tomorrow’s issue of the journal Nature (25 August). The Director General of CERN stirred controversy last month, by saying that the CLOUD team’s report should be politically correct about climate change (see my 17 July post below). The implication was that they should on no account endorse the Danish heresy – Henrik Svensmark’s hypothesis that most of the global warming of the 20th Century can be explained by the reduction in cosmic rays due to livelier solar activity, resulting in less low cloud cover and warmer surface temperatures.

Willy-nilly the results speak for themselves, and it’s no wonder the Director General was fretful.

Jasper Kirkby

Jasper Kirkby of CERN and his 62 co-authors, from 17 institutes in Europe and the USA, announce big effects of pions from an accelerator, which simulate the cosmic rays and ionize the air in the experimental chamber. The pions strongly promote the formation of clusters of sulphuric acid and water molecules – aerosols of the kind that may grow into cloud condensation nuclei on which cloud droplets form. What’s more, there’s a very important clarification of the chemistry involved.

A breach of etiquette

My interest in CLOUD goes back nearly 14 years, to a lecture I gave at CERN about Svensmark’s discovery of the link between cosmic rays and cloudiness. It piqued Kirkby’s curiosity, and both Svensmark and I were among those who helped him to prepare his proposal for CLOUD.

By an unpleasant irony, the only Svensmark contribution acknowledged in the Nature report is the 1997 paper (Svensmark and Friis-Christensen) on which I based my CERN lecture. There’s no mention of the successful experiments in ion chemistry and molecular cluster formation by the Danish team in Copenhagen, Boulby and latterly in Aarhus where they beat CLOUD to the first results obtained using a particle beam (instead of gamma rays and natural cosmic rays) to ionize the air in the experimental chamber – see

What will historians of science make of this breach of scientific etiquette? That Kirkby was cross because Svensmark, losing patience with the long delay in getting approval and funding for CLOUD, took matters into his own hands? Or because Svensmark’s candour about cosmic rays casting doubt on catastrophic man-made global warming frightened the national funding agencies? Or was Kirkby simply doing his best (despite the results) to obey his Director General by slighting all things Danish?

Personal rivalries aside, the important question is what the new CLOUD paper means for the Svensmark hypothesis. Pick your way through the cautious prose and you’ll find this:

Ion-induced nucleation [cosmic ray action] will manifest itself as a steady production of new particles [molecular clusters] that is difficult to isolate in atmospheric observations because of other sources of variability but is nevertheless taking place and could be quite large when averaged globally over the troposphere [the lower atmosphere].”

It’s so transparently favourable to what the Danes have said all along that I’m surprised the warmists’ house magazine Nature is able to publish it, even omitting the telltale graph shown at the start of this post. Added to the already favourable Danish experimental findings, the more detailed CERN result is excellent. Thanks a million, Jasper.

Enlightening chemistry

And in friendlier times we’d be sharing champagne for a fine discovery with CLOUD, that traces of ammonia can increase the production of the sulphuric clusters a thousandfold. It’s highlighted in the report’s title: “Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation” and it was made possible by the more elaborate chemical analysis in the big-team set-up in Geneva. In essence, the ammonia helps to stabilize the molecular clusters.

Although not saying it openly, the CLOUD team implies a put-down for the Danes with this result, repeatedly declaring that without ammonia there’d be little cluster production at low altitudes. But although the Aarhus experimenters did indeed assume the simpler reaction (H2SO4 + H2O), differing results in successive experimental runs made them suspect that varying amounts of trace impurities were present in the air cylinders used to fill their chamber. Now it looks as if a key impurity may have been ammonia. But some members of the CLOUD consortium also favoured (H2SO4 + H2O) and early runs in Geneva used no intentional ammonia. So they’ve little reason to scoff.

In any case, whether the basic chemistry is (H2SO4 + H2O) or (H2SO4 + H2O + NH3) is an academic rather than a practical point. There are always traces of ammonia in the real air, and according to the CLOUD report you need only one molecule in 30 billion. If that helps to oil Svensmark’s climatic motor, it’s good to know, but it calls for no apologies and alters the climatic implications not a jot.

The experiment's logo. The acronym “Cosmics Leaving Outdoor Droplets” always implied strong interest in Svensmark's hypothesis. And the roles of the Galaxy and the Sun are acknowledged.

Technically, CLOUD is a welcome advance on the Danish experiments. Not only is the chemistry wider ranging but molecular clusters as small as 1.7 nanometres in diameter are detectable, compared with 4 nm in Denmark. And the set-up enables the scientists to study the ion chemistry at lower temperatures, corresponding to increasing altitudes in the atmosphere. Cluster production soars as the temperature goes down, until “almost every negative ion gives rise to a new particle” [i.e. molecular cluster]. The lowest temperature reported in the paper is -25 oC. That corresponds to an altitude of 6000 metres, so unless you wish to visualize a rain of cloud-seeding aerosols from on high, it’s not very relevant to Svensmark’s interest in the lowest 3000 metres.

How the warmists built their dam

Shifting from my insider’s perspective on the CLOUD experiment, to see it on the broader canvas of the politicized climate science of the early 21st Century, the chief reaction becomes a weary sigh of relief. Although they never said so, the High Priests of the Inconvenient Truth – in such temples as NASA-GISS, Penn State and the University of East Anglia – always knew that Svensmark’s cosmic ray hypothesis was the principal threat to their sketchy and poorly modelled notions of self-amplifying action of greenhouse gases.

In telling how the obviously large influences of the Sun in previous centuries and millennia could be explained, and in applying the same mechanism to the 20th warming, Svensmark put the alarmist predictions at risk – and with them the billions of dollars flowing from anxious governments into the global warming enterprise.

For the dam that was meant to ward off a growing stream of discoveries coming from the spring in Copenhagen, the foundation was laid on the day after the Danes first announced the link between cosmic rays and clouds at a space conference in Birmingham, England, in 1996. “Scientifically extremely naïve and irresponsible,” Bert Bolin declared, as Chairman of the Intergovernmental Panel on Climate Change.

As several journalists misbehaved by reporting the story from Birmingham, the top priority was to tame the media. The first courses of masonry ensured that anything that Svensmark and his colleagues might say would be ignored or, failing that, be promptly rubbished by a warmist scientist. Posh papers like The Times of London and the New York Times, and posh TV channels like the BBC’s, readily fell into line. Enthusiastically warmist magazines like New Scientist and Scientific American needed no coaching.

Similarly the journals Nature and Science, which in my youth prided themselves on reports that challenged prevailing paradigms, gladly provided cement for higher masonry, to hold the wicked hypothesis in check at the scientific level. Starve Svensmark of funding. Reject his scientific papers but give free rein to anyone who criticizes him. Trivialize the findings in the Holy Writ of the Intergovernmental Panel on Climate Change. None of this is paranoia on my part, but a matter of close personal observation since 1996.

It’s the Sun, stupid!” The story isn’t really about a bunch of naughty Danish physicists. They are just spokesmen for the most luminous agent of climate change. As the Sun was what the warmists really wanted to tame with their dam, they couldn’t do it. And coming to the Danes’ aid, by briefly blasting away many cosmic rays with great puffs of gas, the Sun enabled the team to trace in detail the consequent reduction in cloud seeding and liquid water in clouds. See my post By the way, that research also disposes of a morsel of doubt in the new CLOUD paper, about whether the small specks made by cosmic rays really grow sufficiently to seed cloud droplets.

As knowledge accumulated behind their dam and threatened to overtop it, the warmists had one last course to lay. Paradoxically it was CLOUD. Long delays with this experiment to explore the microchemical mechanism of the Svensmark effect became the chief excuse for deferring any re-evaluation of the Sun’s role in climate change. When the microchemical mechanism was revealed prematurely by the SKY experiment in Copenhagen and published in 2006, the warmists said, “No particle accelerator? That won’t do! Wait for CLOUD.” When the experiment in Aarhus confirmed the mechanism using a particle accelerator they said, “Oh that’s just the Danes again! Wait for CLOUD.”

Well they’ve waited and their dam has failed them.

Hall of Shame

Retracing those 14 years, what if physics had functioned as it is supposed to do? What if CLOUD, quickly approved and funded, had verified the Svensmark effect with all the authority of CERN, in the early 2000s. What if the Intergovernmental Panel on Climate Change had done a responsible job, acknowledging the role of the Sun and curtailing the prophecies of catastrophic warming?

For a start there would have no surprise about the “travesty” that global warming has stopped since the mid-1990s, with the Sun becoming sulky. Vast sums might have been saved on misdirected research and technology, and on climate change fests and wheezes of every kind. The world’s poor and their fragile living environment could have had far more useful help than precautions against warming.

And there would have been less time for so many eminent folk from science, politics, industry, finance, the media and the arts to be taken in by man-made climate catastrophe. (In London, for example, from the Royal Society to the National Theatre.) Sadly for them, in the past ten years they’ve crowded with their warmist badges into a Hall of Shame, like bankers before the crash.


J. Kirkby et al., Nature, 476, 429-433, 2011. The authors list and abstract are available at


H. Svensmark & E. Friis-Christensen, E., J. Atmos. Sol. Terr. Phys., 59, 1225–1232, 1997

Relevant Danish experimental reports since 2006, not cited in the new CLOUD paper

Henrik Svensmark, Jens Olaf Pepke Pedersen, Nigel Marsh, Martin Enghoff and Ulrik Uggerhøj, ‘Experimental Evidence for the Role of Ions in Particle Nucleation under Atmospheric Conditions’, Proceedings of the Royal Society A, Vol. 463, pp. 385–96, 2007 (online release 2006). This was the SKY experiment in a basement in Copenhagen.

Martin Andreas Bødker Enghoff; Jens Olaf Pepke Pedersen; Torsten Bondo, Matthew S. Johnson, Sean Paling and Henrik Svensmark, ‘Evidence for the Role of Ions in Aerosol Nucleation’, Journal of Physical Chemistry A, Vol: 112, pp. 10305-10309, 2008. Experiment in the Boulby deep mine in England.

M.B. Enghoff, J. O. Pepke Pedersen, U. I. Uggerhøj, S. M. Paling, and H. Svensmark, “Aerosol nucleation induced by a high energy particle beam,” Geophysical Research Letters, 38, L09805, 2011. Experiment with an accelerator in Aarhus.

Sun still sulks


Pick of the pics and Climate Change: News and Comments

The Sun still sulks

Two magnetograms from the ESA-NASA SOHO spacecraft contrast the Sun’s liveliness of exactly 10 years ago (20 June 2000) on the left with its feeble performance today (20 June 2010) on the right. In these images made with Stanford’s Michelson Doppler Interferometer, north magnetic polarity is white, south magnetic polarity is black.

Solstice sunrise over Stonehenge 2005. Credit: User: Solipsist.

As many thousands flock to Stonehenge for tomorrow’s summer solstice, this is a moment to ask for the umpteenth time what the Sun is up to. The mean sunspot number in June 2000 was 119, today it is 28, with the spots clustered in the northern region showing most magnetic activity. Since 2004 there have been 803 days with no sunspots at all (35 in 2010, 260 in 2009). During a typical sunspot minimum there are fewer than 500 spotless days.

In the current issue of the Royal Astronomical Society’s magazine Astronomy and Geophysics, Nigel Weiss of Cambridge considers the long-term variability of the Sun and alternative theories about it, especially concerning “grand maxima” in activity like that in the 20th Century, and “grand minima” like the Maunder Minimum of 300 years ago associated with the Little Ice Age. Weiss’s conclusion is that there’s a 40 % chance the current grand maximum will be followed by a grand minimum.

As for the climatic implications, Weiss and I agreed to differ some years ago. Although we both say that the Intergovernmental Panel on Climate Change underestimates the influence of the Sun, Weiss thinks it can’t compete with man-made global warming. His article ends:

Even if the Sun does enter a new Maunder-like grand minimum, any cooling effect will be small compared with the warming produced by anthropogenic greenhouse gases.

Contrast that with Henrik Svensmark’s conclusion in an article for the Danish newspaper Jyllands-Posten.

That the Sun might now fall asleep in a deep minimum was suggested by solar scientists at a meeting in Kiruna in Sweden two years ago. So when Nigel Calder and I updated our book The Chilling Stars, we wrote a little provocatively that “we are advising our friends to enjoy global warming while it lasts.”

In fact global warming has stopped and a cooling is beginning. Mojib Latif from the University of Kiel argued at the recent UN World Climate Conference in Geneva that the cooling may continue through the next 10 to 20 years. His explanation was a natural change in the North Atlantic circulation, not in solar activity. But no matter how you interpret them, natural variations in climate are making a comeback.

The outcome may be that the Sun itself will demonstrate its importance for climate and so challenge the theories of global warming. No climate model has predicted a cooling of the Earth – quite the contrary. And this means that the projections of future climate are unreliable. A forecast saying it may be either warmer or colder for 50 years is not very useful, and science is not yet able to predict solar activity.

So in many ways we stand at a crossroads. The near future will be extremely interesting. I think it is important to accept that Nature pays no heed to what we humans think about it. Will the greenhouse theory survive a significant cooling of the Earth? Not in its current dominant form. Unfortunately, tomorrow’s climate challenges will be quite different from the greenhouse theory’s predictions. Perhaps it will become fashionable again to investigate the Sun’s impact on our climate.


N. Weiss, “Modulation of the Sunspot Cycle”, Astronomy and Geophysics, Vol. 51, pp. 3.9-3.15, 2010

H. Svensmark: “While the Sun sleeps” (in Danish), Jyllands-Posten, 9 September, 2009

For a related post on this blog see

Postscript on the Song of the Sun

I see that Sheffield solar physicists now generate music from observations of the magnetic coronal loops. Read about it (and hear it):

For an earlier Song of the Sun, using its internal vibrations seen by SOHO’s MDI, click on the second item here (but beware – it’s about 18 MB with visuals)

Star positions matter


Updating The Chilling Stars

Why star positions matter for climate physics

The Making of History’s Greatest Star Map is an excellent account of the European Space Agency’s Hipparcos mission by the project scientist, Michael Perryman. It brings back vivid recollections:

  • of dismay after the launch in 1989, when the satellite failed to go into the right orbit and frantic steps were needed to improvise a survivable orbit and re-configure the observing programme.
  • of satisfaction when operations continued despite unplanned exposure to the Earth’s radiation belts, as well as some nasty solar flares, until the radiation damage became fatal in 1993.
  • of the appetizer in 1994, when early results of the Hipparcos star mapping helped in accurate prediction of the impacts of the fragmented Comet Shoemaker-Levy 9 on the planet Jupiter.
  • of joy on Isola di San Giorgo, Venice, in 1997 when the Hipparcos science team announced their first large-scale results, after a huge computational effort.

Hipparcos in an ESA impression

Astrometry took that great leap forward 30 years after Pierre Lacroute of the Strasbourg Observatory first proposed a space mission to measure the positions of stars, 20 years after Erik Høg of the Copenhagen Observatory refined the concept, and 17 years after ESA earmarked it as something to do. Ground-based astrometry had stalled, because of imprecisions due the turbulence of the atmosphere, and its remaining aficionados had little lobbying power. As a result, Hipparcos remained a distinctly European space project – the first in which there was no competition with the US or Soviet space science programmes.

Applications of the Hipparcos Catalogue of 100,000 plus stars and the Tycho 2 Catalogue with 2.5 million stars (to a lesser but still unprecedented accuracy) have ranged from detecting a bend in the Milky Way Galaxy to checking Einstein’s theory of gravity, General Relativity. But wanting to pursue here the relevance of Hipparcos to climate physics, I’m pleased to see that Michael Perryman points the way.

Michael Perryman. Photo by Richard Perryman

In The Making of History’s Greatest Star Map, pp. 236-243, Perryman notes the role of Hipparcos in refining observations the wobbles of the Earth’s axis, which are involved in the pacing of ice ages (the Milankovitch theory). Then he points to the link between solar activity and climate change, as evidenced by the Little Ice Age, the Medieval Warm Period and other variations. As to the mechanism for the solar connection, Perryman singles out the suggestion that cosmic rays, modulated by solar activity, influence cloud cover.

He continues the story with the Sun’s journey through the Galaxy and the icy intervals on Earth that correspond to exposure to intense cosmic rays when passing through spiral arms. That’s a major topic in The Chilling Stars and, as Perryman says, the Hipparcos data have improved our knowledge of motions in the Galaxy.

It’s reassuring when a professor of astronomy with no scientific or political axe to grind gives serious attention to the cosmic-ray/climate link (the Svensmark hypothesis). Let me reciprocate by reviewing what’s said about the climate-related significance of Hipparcos and its successor Gaia in The Chilling Stars and see if it needs updating or extending.

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