Category: Videnskab

Hvad er problemet med Intelligent Design?

Det skrev jeg forleden en kommentar om ovre på Pleiotropy, som egentlig fortjener at ophøjes til et helt indlæg her. Kommentaren tager udgangspunkt i en bemærkning om, at irreducibel kompleksitet – argumentet om, at en levende organisme er så kompleks, at fjernelsen af blot en enkelt komponent vil få den til at fejle, og derfor kan den ikke være opstået ved en tilfældighed – egentlig er et sundt, videnskabeligt argument, der er bare ingen observationer, der peger i retning af, at det er relevant for livets opståen her på Jorden:

First of all, I think that the argument of irreducible complexity is a bad argument because it’s a reductio ad absurdum.

Such arguments work extremely well in mathematics, but in empirical science their track record is bad because some way around the “absurdity” might be found which the proposer of the theory hadn’t thought of.

E.g., the existence of the ether was once considered necessary, even proven, because waves (light) can’t propagate in nothing, i.e. vacuum.

Except they apparently could: No positive evidence could be found for the existence of the ether, and in 1905 Einstein famously showed that the ether is not necessary for the consistency of the theory of electromagnetism.

Likewise, saying that irreducibly complex systems can’t arise spontaneously is equal to saying just about nothing, since in some cases they actually can – in physics I believe we see it in chaotic systems and resonance phenomena.

So if the ID people and creationists really wanted to go places they’d want to find positive evidence that point to a creator or designer – evidence that could supposedly tell us something about said designer’s nature, tools, methods, etc. Alas, such a theory is probably not forthcoming.

Carl Sagan had an outrageous idea in one of his novels, that the Creator had signed his work by embedding a representation of a picture of a circle in the decimals of Pi – the ID people would have to come up with something similar if we are to take them seriously.

Even so, I tend to agree that the argument of irreducible complexity is scientific, even if it is potentially flawed. However, I think that what makes the ID theories really not science is that they’re not falsifiable – there’s no experiment we could design or perform which would make these people change their mind. And if you’ve already made up your mind (or let your religious ideas make up your mind) as to what class of phenomena you will accept from Nature and what kind of theories you will use to describe them, then you’re not a scientist period.

Pleiotropy er i øvrigt et godt sted at gå hen, hvis man gerne vil læse kvalificerede indlæg om evolutionsbiologi, striden om Intelligent Design og en masse andre beslægtede emner.

Link: Why teach Intelligent Design?

Dagens citat: Vi ser ikke verden, vi hallucinerer os frem til den

Ray Kurzweil, i et interview til Asimov’s et par år tilbage:

We don’t actually see things, we essentially hallucinate them in detail from what we see from these low resolution cues. Past the early phases of the visual cortex, detail doesn’t reach the brain.

Hvilket selvfølgelig er velkendt og for mange sikkert såre banalt, men her rammende udtrykt.

Illusionen om øjnene som “vinduesglas”, som vi sidder og kigger ud på verden med er slet og ret dette, en illusion – vore øjne kan faktisk kun detektere kontraster, hvad der gør alle de ensartede flader, vores synssans plejer at forsyne verden med, lidt suspekte.

Dagens citat: Psykiatrisk cirkelslutning

Fra Joanna Moncrieff: The Myth of the Chemical Cure, Palgrave MacMillan 2008, s. 65:

Although nowadays the dopamine theory of psychosis and schizophrenia is central to the idea that antipsychotic drugs have a disease-centred action, it was the presumption that the drugs exerted a disease-specific action that was the initial inspiration for the dopamine theory.

Altså: Hele forestillingen om, at schizofreni er forårsaget af for høje niveauer af dopamin er afledt af  den omstændighed, at neuroleptika og andre antipsykotiske stoffer påvirker niveauet af dopamin og synes at medføre en bedring hos sådanne patienter.

Hvis det nu viste sig, at teorien om, at depression er forårsaget af for lave niveauer af serotonin og noradrenalin var inspireret af den kemiske virkning af tricykliske antidepressiva og SSRI-inhibitorer…

og hvis det endvidere viste sig, at en fordomsfri undersøgelse af disse stoffers virkning ikke kan godtgøre, at de skulle have nogen specifikt helbredende virkning, hverken mod psykose eller depression, så ville skandalen – og afsløringen af årtiers medicinsk fejlbehandling  – være komplet. Eller hvad?

Hvorom alting er, Moncrieffs bog kan anbefales.

Klima-SOS

Jeg har modtaget nedenstående i en email og iler med at give opfordringen videre (tak, Rene):

NU GØR VI NOGET FOR KLIMAET – PÅ NETTET

Hvis du er en af de mennesker, der bekymrer sig om klimaet i disse globale opvarmningstider, og vil du have at politikerne skal gøre noget ved det – så start med at SENDE ET POSTKORT TIL EN FOLKETINGSPOLITIKER – ganske gratis her på dette link:

www.klima-sos.dk

I de næste ti dage går hele den del af Danmarks befolkning, som tager ansvar for fremtiden i gang med at fylde det danske web med opfordringer til, at folk skal deltage i denne kampagne. Det gør vi fordi, at vi forlanger, at Danmark skal have en stærk Klimalov, der sikrer bindende årlige reduktioner på 6 % i udledningen af drivhusgasser. En lov der er bedre end den, man allerede har opnået i England med The Big Ask kampagnen. Se film om kampagnen her:

Tag ansvar for fremtiden – gør din del – sådan kan du gøre:

1. Skriv under – www.klima-sos.dk

2. Vær aktiv på facebook:

Join Klima SOS gruppen, Klima SOS eventen, Klima SOS cause og få dine venner med.

Videresend denne besked til alle dine venner.

Få administratorerne på de grupper du tilmeldt til at videresende denne.

Poste www.klima-sos.dk på din mur.

3. Fyr den op på andre sider fx:

Myspace, Arto osv.

Debatsider på BT, DR, JP, Politiken, Berlingske, Femina, Ingeniøren, samt diverse blogs og alle andre mulige steder på nettet.

4. Send mail ud til hele dit netværk med teksten:

GØR EN INDSATS FOR EN STÆRK KLIMALOV I DANMARK.

BINDENDE ÅRLIGE REDUKTIONER I UDLEDNING AF DRIVHUSGASSER.

Gå til WWW.KLIMA-SOS.DK, send et elektronisk postkort til en politiker og fortæl andre om kampagnen. Videresend

5. Er du med i en miljø- eller udviklingsorganistion, send en personlig opfordring til dem om at opsætte Klima SOS bannere osv. på deres hjemmeside og nævne reklamen i nyhedsmails.

GÅ AMOK, FØR KLIMAET GØR DET!

Klima SOS kampagnen er startet af miljøbevægelsen Noah og støttes af Klimabevægelsen i Danmark, Samvirkende Energi- og Miljø-foreninger.

Læs også:

• Klima versus vejr – hvorfor vejrets uforudsigelighed ikke hindrer forudsigelsen af global opvarmning

• Klimadebat, CO2 og miljø

‘Jødisk-kristen’ kultur eksisterer ikke

Razib gør ovre på Gene Expression/Science Blogs opmærksom på, at dén “jødisk-kristne kultur” eller “jødisk-kristne kulturkreds”, som mange har det med at henvise til, når de skal slå ud med armene og holde skåltaler, ret beset ikke eksisterer og aldrig har eksisteret.

De europæiske jøder var f.eks. slet ikke en del af den vestlige kulturkreds før den jødiske oplysningstid omkring år 1800.

Hvis man ønsker at klassificere de tre store “Abrahamske” religioner, har jødedommen og islam bevaret sit traditionelle, orientalske “lov-præg”, mens kristendommen er voldsomt påvirket af græsk filosofi. Hvis man endelig ville, kunne man tale om en jødisk-islamisk versus en kristen religiøs og kulturel kultur.

Razib uddyber:

My own position from a phylogenetic viewpoint is that Rabbinical Judaism, the dominant form of Judaism between 500 to 1800, resembles Islam much more than Christianity. Islam and Rabbinical Judaism have a more orthopraxic orientation (e.g., Halakah, Sharia) and less of a focus on Greek tinged theology than Christianity. I have pointed out before that Rabbinical Jews had arguments as to whether Christians were, or were not, monotheists, but agreed than Muslims were. I agree that some strands within both Judaism and Islam don’t fall into the bounds of this narrative, but these streams have been marginalized for most of the past 2,000 years, just as Judaizing movements within Christianity were never dominant or influential until the Radical Reformation (though I would contend that the Judaizing of most Radical Protestants is rather weak tea, and only notable due to the de-Judaization of Pauline Christianity). I am claiming here that the Great Tradition of Christianity is the outlier when it comes to the various strands of the Abrahamic faiths (along perhaps with the extreme rationalists among the Mu’tazili and various Jewish schismatic groups).

Why does this matter? Because the term Judeo-Christian makes everything I said above totally surprising. Rather, it might give the impression that what we know of as Reform Judaism was the norm for Judaism in the West for the past 2,000 years. I think a clustering of Reform Judaism with mainline Protestant Christianity is very plausible. What I’m trying to say is that if you had all the mainstream branches of Judaism and Christianity and generated a a phylogenetic tree, Judaism would be a paraphyletic class (Reform Jews being accepted as Jews, while Christians are not). But it isn’t only history that is misrepresented by the Judeo-Christian model, most people are rather ignorant, so trying to portray Islam as an outgroup to Judaism, instead of highlighting its similarities of character with Orthodox Judaism, simply wastes the opportunity to impart information-by-analogy to lazy people who can’t be bothered to learn anything about Islam. The reality is most ignorant people will remain that way, and will continue to talk about issues which relate to categories which they are grossly ignorant of (e.g., various religious sects and groups). “Judeo-Christian” compounds the follies of modal stupidity.

Så ifølge det argument giver det altså slet ikke mening at tale om en “jødisk-kristen” kulturkreds. Hvad der giver mening er at tale om et “moderne”, areligiøst eller sekulariseret verdensbillede – ca., hvad man forstår ved det moderne “videnskabelige” verdensbillede.

Dette omfatter i Vesten ateister og agnostikere af jødisk, kristen og i vore dage også islamisk baggrund (tre gode eksempler er fysikerne Albert Einstein, Niels Bohr og Richard Feynman – alle af jødisk baggrund, men med et  sekulært livssyn). Men “jødisk-kristent” er det ikke – det er, som sagt, “moderne” eller “ateistisk”. Hvis vi endelig vil klassificere kulturerne rent religiøst er det, som Razib påpeger, jødedommen og islam der hører sammen, og kristendommen der skiller sig ud.

Link: Gene Expression om begrebet ‘jødisk-kristen’

Klima versus vejr – hvorfor vejrets uforudsigelighed ikke hindrer forudsigelsen af global opvarmning

Jeg lagde egentlig dette som kommentar ovre på Uriasposten, men da jeg ikke forventer, at den kan overbevise mange derovre, poster jeg det her også, hvor det måske kan falde i lidt mere frugtbar jord.

En hyppig indvending mod observationen af global opvarmning og forudsigelsen af, at den vil fortsætte er, at vi ikke engang kan forudsiget vejret pålideligt mere end få dage frem – hvordan kan vi så udtale os om klimaet, dvs. vejret på hele Jorden, mange år frem i tiden?

Man skulle tro, at det ene udelukkede det andet. Men sådan er det ikke:

At forudsige klima og vejr er ikke det samme. Vejret er et kaotisk system, hvor vi især er interesseret i detaljer om, hvordan det opfører sig helt lokalt.

Når vi taler klima kan vi anskue hele Jorden som et termodynamisk system med en række egenskaber, der skal være i termodynamisk balance med primært Solen.

Simple fysiske love som energibevarelsen, Stefan-Boltzmanns lov og atmosfærens absorptionsspektrum tillader os at udtale os på et overordnet plan om, hvordan klimaet og især temperaturen vil opføre sig, hvis forskellige ting sker. En af de lidt enklere ting er, at hvis man øger koncentrationen af drivhusgasser i atmosfæren, vil temperaturen stige. Dette er ganske enkelt, fordi drivhusgasserne absorberer noget af Jordens varmespektrum, hvorfor Jorden har brug for en højere temperatur for at opnå en effekt, der svarer til den effekt, den modtager fra Solen.

At CO2 er en drivhusgas, har man vidst, siden John Tyndall opdagede det i det 19. århundrede. At koncentrationen af CO2 i atmosfæren er steget kraftigt de sidste hundrede år er let at verificere. Herefter er det sådan set bare at opstille nogle modeller og regne på det.

Mht. spørgsmålet om “vejr” vs. “klima” er der en temmelig perfekt analogi i den klassiske termodynamik: Vi ved, at en gas består af mange millioner molekyler, der bevæger sig i et kaotisk og uforudsigeligt mønster. Vi kan derfor ikke forudsige, hvordan disse molekyler bevæger sig lokalt.

Men vi kan anstille nogle statistiske betragtninger, der tillader os at bruge reglerne for ideale gasser om større mængder uden at kende molekylernes bevægelser. F.eks. ved vi, at tryk gange rumfang er proportionalt med temperaturen.

Fuldstændig analogt: Selvom vi ikke kan give alle detaljerne (vejret) kan vi sagtens anvende nogle helt grundlæggende fysiske love (primært energibevarelse og strålingslove) til at sige noget om systemet som helhed (klimaet).

Hvis nogen er mere interesseret i videnskaben bag den globale opvarmning, har American Institute of Physics lavet en side, der fortæller om opdagelsens historie og forklarer (populært) om de videnskabelige principper, der er involveret.

Læs også:

• The Discovery of Global Warming (American Institute of Physics)
• Klimadebat, CO2 og miljø

Klimaforandring – hvad ved vi, og hvor kom det fra?

American Institute of Physics har en glimrende side med baggrund og oplysning om global opvarmning, herunder en forklaring på, hvor den eksisterende videnskabelige konsensus om CO2 som en væsentlig faktor i global opvarmning kommer fra.

Læs bl.a.:

In 1896 a Swedish scientist published a new idea. As humanity burned fossil fuels such as coal, which added carbon dioxide gas to the Earth’s atmosphere, we would raise the planet’s average temperature. This “greenhouse effect” was only one of many speculations about climate, and not the most plausible. Scientists found good reason to believe that our emissions could not change the climate. Anyway major change seemed impossible except over tens of thousands of years.

In the 1930s, people realized that the United States and North Atlantic region had warmed significantly during the previous half-century. Scientists supposed this was just a phase of some mild natural cycle, with unknown causes. Only one lone voice, the amateur G.S. Callendar, insisted that greenhouse warming was on the way. Whatever the cause of warming, everyone thought that if it happened to continue for the next few centuries, so much the better.

In the 1950s, Callendar’s claims provoked a few scientists to look into the question with improved techniques and calculations. What made that possible was a sharp increase of government funding, especially from military agencies with Cold War concerns about the weather and the seas. The new studies showed that, contrary to earlier crude estimates, carbon dioxide could indeed build up in the atmosphere and should bring warming. Painstaking measurements drove home the point in 1961 by showing that the level of the gas was in fact rising, year by year.

Over the next decade a few scientists devised simple mathematical models of the climate, and turned up feedbacks that could make the system surprisingly variable. Others figured out ingenious ways to retrieve past temperatures by studying ancient pollens and fossil shells. It appeared that grave climate change could happen, and in the past had happened, within as little as a few centuries. This finding was reinforced by computer models of the general circulation of the atmosphere, the fruit of a long effort to learn how to predict (and perhaps even deliberately change) the weather. A 1967 calculation suggested that average temperatures might rise a few degrees within the next century. The next century seemed far off, however, and the calculations were plainly speculative. Groups of scientists that reviewed the issue saw no need for any policy actions, although they did draw official attention to the need for a greater research effort.

In the early 1970s, the rise of environmentalism raised public doubts about the benefits of human activity for the planet. Curiosity about climate turned into anxious concern. Alongside the greenhouse effect, some scientists pointed out that human activity was putting dust and smog particles into the atmosphere, where they could block sunlight and cool the world. Moreover, analysis of Northern Hemisphere weather statistics showed that a cooling trend had begun in the 1940s. The mass media (to the limited extent they covered the issue) were confused, sometimes predicting a balmy globe with coastal areas flooded as the ice caps melted, sometimes warning of the prospect of a catastrophic new ice age. Study panels, first in the U.S. and then elsewhere, began to warn that one or another kind of future climate change might pose a severe threat. The only thing most scientists agreed on was that they scarcely understood the climate system, and much more research was needed. Research activity did accelerate, including huge data-gathering schemes that mobilized international fleets of oceanographic ships and orbiting satellites.

Earlier scientists had sought a single master-key to climate, but now they were coming to understand that climate is an intricate system responding to a great many influences. Volcanic eruptions and solar variations were still plausible causes of change, and some argued these would swamp any effects of human activities. Even subtle changes in the Earth’s orbit could make a difference. To the surprise of many, studies of ancient climates showed that astronomical cycles had partly set the timing of the ice ages. Apparently the climate was so delicately balanced that almost any small perturbation might set off a great shift. According to the new “chaos” theories, in such a system a shift might even come all by itself — and suddenly. Support for the idea came from ice cores arduously drilled from the Greenland and Antarctic ice sheets. They showed large and disconcertingly abrupt temperature jumps in the past.

Greatly improved computer models began to suggest how such jumps could happen, for example through a change in the circulation of ocean currents. Experts predicted droughts, storms, rising sea levels, and other disasters. A few politicians began to suspect there might be a public issue here. However, the modelers had to make many arbitrary assumptions about clouds and the like, and reputable scientists disputed the reliability of the results. Others pointed out how little was known about the way living ecosystems interact with climate and the atmosphere. They argued, for example, over the effects of agriculture and deforestation in adding or subtracting carbon dioxide from the air. One thing the scientists agreed on was the need for a more coherent research program. But the research remained disorganized, and funding grew only in irregular surges. The effort was dispersed among many different scientific fields, each with something different to say about climate change.

One unexpected discovery was that the level of certain other gases was rising, which would add seriously to global warming. Some of these gases also degraded the atmosphere’s protective ozone layer, and the news inflamed public worries about the fragility of the atmosphere. Moreover, by the late 1970s global temperatures had evidently begun to rise again. International panels of scientists began to warn that the world should take active steps to cut greenhouse gas emissions. The scientists’ claims about climate change first caught wide public attention in the summer of 1988, the hottest on record till then. (Most since then have been hotter.) But the many scientific uncertainties, and the sheer complexity of climate, made for vehement debate over what actions, if any, governments should take. Corporations and individuals who opposed all government regulation spent large sums to convince people that there was no problem at all.

Scientists intensified their research, organizing programs on an international scale. The world’s governments created a panel to give them the most reliable possible advice, as negotiated among thousands of climate experts and officials. By 2001 this Intergovernmental Panel on Climate Change managed to establish a consensus, phrased so cautiously that scarcely any expert dissented. They announced that although the climate system was so complex that scientists would never reach complete certainty, it was much more likely than not that our civilization faced severe global warming. At that point the discovery of global warming was essentially completed. Scientists knew the most important things about how the climate could change during the 21st century. How the climate would actually change now depended chiefly on what policies humanity would choose for its greenhouse gas emissions.

Link: The Discovery of Global Warming (via Boing Boing).

Læs også: Klimadebat, CO2 og miljø

Det er tåbeligt at lovgive mod Holocaust-benægtelse

Lad det være sagt med det samme og på forhånd: Holocaust-benægterne har ikke en sag. Holocaust er én af det 20. århundredes bedst og grundigst dokumenterede begivenheder, og for at benægte det skal man enten være meget uvidende, have store ideologiske skyklapper på eller have et ganske bestemt ideologisk sigte.  Men når det er sagt, er det stadig en ret tåbelig idé at ville lovgive om, hvilke historiske teorier eller påstande, der kan fremsættes.

Lad os hellere tage debatten for åben pande og med udgangspunkt i empiriske fakta, som i tilfældet med Holocaust ikke er svært tilgængelige.

Timothy Garton Ash påpeger absurditeten i en kommentar i dagens Guardian:

More and more countries have laws saying you must remember and describe this or that historical event in a certain way, sometimes on pain of criminal prosecution if you give the wrong answer. What the wrong answer is depends on where you are. In Switzerland, you get prosecuted for saying that the terrible thing that happened to the Armenians in the last years of the Ottoman empire was not a genocide. In Turkey, you get prosecuted for saying it was. What is state-ordained truth in the Alps is state-ordained falsehood in Anatolia.

This week a group of historians and writers, of whom I am one, has pushed back against this dangerous nonsense. In what is being called the “Appel de Blois”, published in Le Monde last weekend, we maintain that in a free country “it is not the business of any political authority to define historical truth and to restrict the liberty of the historian by penal sanctions”. And we argue against the accumulation of so-called “memory laws”. First signatories include historians such as Eric Hobsbawm, Jacques Le Goff and Heinrich August Winkler. It’s no accident that this appeal originated in France, which has the most intense and tortuous recent experience with memory laws and prosecutions. It began uncontroversially in 1990, when denial of the Nazi Holocaust of the European Jews, along with other crimes against humanity defined by the 1945 Nuremberg tribunal, was made punishable by law in France – as it is in several other European countries. In 1995, the historian Bernard Lewis was convicted by a French court for arguing that, on the available evidence, what happened to the Armenians might not correctly be described as genocide according to the definition in international law.

A further law, passed in 2001, says the French Republic recognises slavery as a crime against humanity, and this must be given its “consequential place” in teaching and research. A group representing some overseas French citizens subsequently brought a case against the author of a study of the African slave trade, Olivier Pétré-Grenouilleau, on the charge of “denial of a crime against humanity”. Meanwhile, yet another law was passed, from a very different point of view, prescribing that school curricula should recognise the “positive role” played by the French presence overseas, “especially in North Africa”.

Mine fremhævelser. I forlængelse af et argument oprindelig fremført af den borgerlige, liberale tænker John Stuart Mill i hans uomgængelige On Liberty: Hvis det ikke er tilladt at argumentere imod sandheden, mister den sin værdi og bliver et arbitrært diktat.

Hvis det ikke er tilladt at forsøge at finde alternative forklaringer på bestemte historiske begivenheder, mister disse begivenheder i sidste ende deres sandhed. Og de empiriske data om Holocaust klarer sig, skulle jeg hilse og sige, særdeles godt mod Holocaust-benægternes usandsynlige og søgte konspirationsteorier. Men hvis nogen mener at kunne argumentere for noget andet, skal vi da have lov til at høre argumenterne, før vi eventuelt skyder dem ned.

Som eksemplet med Bernard Lewis (som jeg ellers ikke er nogen stor fan af) viser, kan det meget hurtigt ende med at blive en ubehagelig glidebane.

Som Garton Ash spørger:

This kind of nonsense is all the more dangerous when it comes wearing the mask of virtue. A perfect example is the recent attempt to enforce limits to the interpretation of history across the whole EU in the name of “combating racism and xenophobia”. A proposed “framework decision” of the justice and home affairs council of the EU, initiated by the German justice minister Brigitte Zypries, suggests that in all EU member states “publicly condoning, denying or grossly trivialising crimes of genocide, crimes against humanity and war crimes” should be “punishable by criminal penalties of a maximum of at least between one and three years imprisonment”.

Who will decide what historical events count as genocide, crimes against humanity or war crimes, and what constitutes “grossly trivialising” them?

Ytrings- og forskningsfriheden må i hvert fald og altid omfatte friheden til at rejse historiske spørgsmål og forsøge at belyse dem empirisk, uanset hvor “politisk korrekt” resultatet må være eller ej. Om ikke andet, fordi denne politiske korrekthed er en vejrhane, der skifter med det politiske klima – men mest af alt, fordi indstiftelsen af en officiel historisk sandhed, der ikke må modsiges, ganske enkelt reducerer den historiske forskning til pjat og tidsspilde.

Og hermed mister de begivenheder, hvis betydning disse velmente men tåbelige love forsøger at beskytte, netop dette: Deres betydning.

Link: The freedom of historical debate is under attack by the memory police

Nej, Jorden går ikke under i dag

Heller ikke i dag.

Lad mig bare citere, hvad jeg i går citerede en fysiker for: “Look, it’s a 10^-19 chance, and you’ve got a 10^-11 chance of suddenly evaporating while shaving.”

En ting man overser i denne diskussion – eller som nogen overser – er, at naturen har udført denne type højenergi-eksperimenter i millioner af år uden at det har medført særligt katastrofale resultater. Hvis der havde været noget om snakken, ville månen have været væk for længe siden …

Update: CERN gør på sin hjemmeside opmærksom på en ny artikel i Journal of Physics G, der konkluderer, at eksperimentet er sikkert:

The safety of collisions at the Large Hadron Collider (LHC) was studied in 2003 by the LHC Safety Study Group, who concluded that they presented no danger. Here we review their 2003 analysis in light of additional experimental results and theoretical understanding, which enable us to confirm, update and extend the conclusions of the LHC Safety Study Group. The LHC reproduces in the laboratory, under controlled conditions, collisions at centre-of-mass energies, less than those reached in the atmosphere by some of the cosmic rays that have been bombarding the Earth for billions of years. We recall the rates for the collisions of cosmic rays with the Earth, Sun, neutron stars, white dwarfs and other astronomical bodies at energies higher than the LHC. The stability of astronomical bodies indicates that such collisions cannot be dangerous. Specifically, we study the possible production at the LHC of hypothetical objects such as vacuum bubbles, magnetic monopoles, microscopic black holes and strangelets, and find no associated risks. Any microscopic black holes produced at the LHC are expected to decay by Hawking radiation before they reach the detector walls. If some microscopic black holes were stable, those produced by cosmic rays would be stopped inside the Earth or other astronomical bodies. The stability of astronomical bodies strongly constrains the possible rate of accretion by any such microscopic black holes, so that they present no conceivable danger. In the case of strangelets, the good agreement of measurements of particle production at RHIC with simple thermodynamic models severely constrains the production of strangelets in heavy-ion collisions at the LHC, which also present no danger.

Du kan læse hele artiklen her.

Enden er nær: Politiken sælger ud til dårlig videnskab

Jorden kan gå under i morgen, udbasunerer Politiken.dk – motivet er selvfølgelig den berømte partikelaccelerator i CERN, som nogle obskurantister og New Age-folk har advaret mod, fordi den nok vil skabe et sort hul, der vil suge hele Jorden og verden som vi kender den til sig.

Nuvel, vi har skrevet om det før, og dengang skrev vi bl.a.:

Verdens undergang er nært forestående. Det mener i hvert fald to amerikanske “forskere”, hvoraf den ene er advokat med en førstedel i biologi, hvorfor de har besluttet at lægge sag an mod CERN for at få stoppet centrets planlagte “Large Hadron Collider” (LHC).

Fysiker og anerkendt skarpretter af dårlig videnskab i medierne Bob Park ripper anderledes op i retssagens “relevans” og karakteren af den fare, verden svæver i:

LHC: A KNIGHT ERRANT TILTS AT HIGH-ENERGY WINDMILL.

Technology has changed in the 400 years since Cervantes first told the story of Don Quixote. Windmills are now particle accelerators and the knight’s lance is a federal court injunction, but the plot is the same.

It begins with a befuddled lawyer in Hawaii named Walter Wagner. Having read far too much science fiction as a youth, Wagner fantasizes that he is a physicist by virtue of an undergraduate biology degree with a minor in physics. Accompanied by Sancho, his loyal TA, Wagner embarks on an adventure to slay the Large Hadron Collider (LHC), a doomsday machine that he believes is posed to destroy the world by creating a black hole. He seems to have forgotten the last time he tried this. In 1999 Wagner warned that RHIC, the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, must be slain lest it create a black hole. The then BNL director, Jack Marburger, named a distinguished panel of physicists to investigate. Their report noted that nature has been conducting the relevant safety test for billions of years by colliding heavy-ion cosmic rays with the moon. It concluded that creation of a black hole is “effectively ruled out by the persistence of the Moon”.

Og hvad kan man så lære af det? At verden er fuld af idioter og nogle af dem elsker at lave larm, og at Jyllands-Postens journalist Morten Vestergaard er for ukritisk i sin vinkling af de to “forskeres” bekymring. Ellers intet nyt under solen.

BoingBoing citerer en mere nøgtern faglig vurdering: “Look, it’s a 10^-19 chance, and you’ve got a 10^-11 chance of suddenly evaporating while shaving.”

Og i dag kan vi så konkludere, at også Politiken har meldt sig i idoternes eller i hvert fald de ukritiske ignoranters rækker.

Update, 10/9: I dag får vi så  i det mindste syn for sagn.