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Svensmark and Supernovae

24 April 2012

At ftp://ftp2.space.dtu.dk/pub/Svensmark/MNRAS_Svensmark2012.pdf 'Evidence of nearby supernovae affecting life on earth' can be found at various sites including Benny Peiser's CCNet, via www.thegwpf.org and at www.ras.org.uk/news-and-press/219-news-2012/2117-did-exploding-stars-hel… … the paper itself, see first link, is published by the Monthly Notices of the Royal Astronomical Society. Svensmark has been forced to go outside climate science journals as peer review would have caused problems with climate scientist especially antagonistic towards his work. The subject is also astronomical, hence the shift to a more amenable publisher is broadly in line with what is written – if not what is implied. Svensmark seems to have trawled through 500 million years of uniformitarian geochronology and astronomical retrocalculated data  in order to look at where the Sun was in the Galaxy and its proximity to nearby supernova – or suspected regions of supernovae activity. For example, when the Sun and it's planets pass through the spiral arms of the Milky Way galaxy it can encounter newly forming clusters of stars – and these involve supernova explosions, or so it is thought. He then compares this with geological events and deduced supernovae shaped conditions for life on earth. Whenever the solar system has come into contact with regions of enhanced star formation life has prospered, he claims, and that is the nutshell of it all. Nigel Calder at http://calderup.wordpress.com/a-stellar-revision-of-the-story-of-life/ or Svenmark's 'Cosmic Jackpot' as he describes it, was a collaborator with Svensmark on their book, The Chilling Stars. He is naturally enthusiastic and begins his post with the Pleiades, saying they were born during the Dinosaur Age and were active over 40 million years ago (but this fails to explain why in Palaeolithic and fairly recent times the Pleiades figure so much in myth around the world). The remnants of the supernovae that created the Pleiades created cosmic rays and he goes on to describe the process used by Svensmark. Exploding stars, it is hypothesized, cooled the world by creating cloud cover and this may explain why evolution was sometimes rampant and at other times it was ponderous and slow, or had even come to a halt. Obviously, this theory could make catastrophism obsolete – so it is interesting how it develops. Calder is enthusiastic but it relies on uniformitarian geochronology which is not doubted, it seems, by either Svensmark or Calder. Is it possible that geologists have got it right – down to the nearest million years? This can hardly be and it was a human calculation and is therefore subject to correction whenever evidence to the contrary is forthcoming. Geochronology is a largely academic exercise – not a fact. The Dinosaur Age may have ended around 63 million years ago – or it may have ended somewhat nearer, or further away. If Svensmark has found a fit one must wonder why – how can it be that a few bods in leather armchairs can derive an exact geological timescale that is unalterable and binding and is it just a bit of luck that it happens to fit the evidence from an astronomical retrocalculation of the movement of the Milky Way galaxy. Are academics that clever?

What other motives might lie behind this paper? Again, Calder provides the clue. It is the climate change dispute. Svensmark stands the popular co2 story on it's head, it is claimed – but is this wishful thinking? Some geologists seek to claim alterations between hot and cold periods of the past were due to rising or falling levels of co2 in the atmosphere, an obvious spin-off from global warming science models. In addition, some geologists see a link between warm and cold periods and changes in sea level – rising in times of warmth (such as the Dinosaur Age). In reality it is a theory that sea levels rose in times of warmth, or that tropical conditions in now temperate or Arctic regions of the world actually denotes warmer global conditions and therefore with icecaps that must have melted, but never the less, Svensmark also manages to insert sea level change into his scheme of biodiversity change associated with the movement of the solar system across the spiral arms of our galaxy. Supernovae, he says, influenced the biodiversity of marine invertebrate animals such as the trilobites, etc. These are common fossils found in certain geological deposits – and few or absent from other strata. In doing so he reinterprets the Permian-Triassic boundary event, discarding the possibility of catastrophe and blames it all on supernovae chilling the planet.

At http://wattsupwiththat.com/2012/04/24/svensmarks-cosmic-jackpot-evidence… … Anthony reduces some of the arguments. In 1) long term biodiversity in life in the sea depends on the sea level set by plate tectonics and the supernovae rate set by astrophysics and on virually nothing else, 2) the long term primary productivity of life in the sea, the net growth of photosynthetic microbes, depends on the supernovae rate and on virtually nothing else, 3) exceptionally close supernovaes account for short lived drops in sea level over the last 500 million years, long known to geophysicists but never adequately explained, and 4) as the geological and astronomical records converge, the match between climate and supernovae rate gets better and better, with high rates bringing icy times (the Ice Ages).

It is all supposed to mesh like clockwork but the comments, from down to earth people with a little pragmatism, are worth trawling. For example, Polistra at 7.33am may hit the mark spot on. The Grnad Universal Theory is a surprise, he says, I thought Svensmark and Calder's main interest was climate, not life of earth. We might ask, with that in mind, is it a mega-study with a single purpose – to nix the co2 theory? The comment at 8.05am is interesting as it harks back to Stephen J Gould's 'punctuated equilibrium in the rate of evolution' and we may also wonder if Svensmark has Gould in mind when he talks about changes in the rate of biodiversity. Stephen Wilde at 8.11am is sceptical and says variation in cosmic rays reaching the surface are merely a proxy for solar variability – but he would say that. Taphonic at 8.15am also scores a bullseye. Plate tectonics is not continental drift – the mechanism behind the theories differs. Is Svensmark up to date in his geology? Vukcevic adds at 8.18am 'cosmic ray science appear to be uncertain what was going on a month ago yet alone thousands or millions of years ago' (see www.vukcevic.talktalk.net/Ap-Cl.htm).

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