Letters to the Editor

• Sheesh, will DS ever stop digging

  [Read the article: Our rosy future, according to Freeman Dyson]
  [Read more letters about this article: Here]

  Cripes . . .

  Plutonium is decaying very slowly, emitting mostly alpha particles, but to ingest enough or get it on your lungs to do you serious damage in the short term would be tough -- and that indeed is the point. It is chemically toxic -- it is after all a (very) heavy metal, with all of the toxicity issues that brings. Indeed, the big question with say Depleted Uranium antitank rounds may be the chemical toxicity of the fine fragments it creates. The problems with DU may indeed have been underestimated because of focus only on well modeled radiation effects of not very radioactive DU.

  In the scheme of things anyone who has had a radiation safety course learns the issues -- gamma and x-ray is more penetrating than beta, but interacts less, so it will go further, but small fluxes will do much less damage; beta is most dangerous -- it penetrates more effectively, and also has high interaction with matter, i.e., it is more likely to damage tissues and cause cancer; alpha is a very poor penetrator, but very high interaction -- so outside the body it is fairly safe, but inside a serious problem.

  Alpha and beta particles are decay products, unlike gamma -- so the longer the half life, the less alpha/beta radiation. To put it another way, the amount of Polonium 110 that would cause fatal radiation poisoning is a tiny fraction of the amount of Plutonium 239 necessary to have the same effect.

  Perversely, the extreme radioactivity of used nuclear fuel rods has a major advantage, they are pretty tough to steal, since they are not something a thief could safely get close to.

  Grubert - as far as the compernican/ptololomaic point is concerned, observation instruments was a key factor, in part because for some observations, mainly some distant stars, copernican v. ptolomaic models both yield valid results, as well as of course the problem of the moon.

  You are of course correct in saying that quantum mechanics helped solve certain issues, but in the early days there were serious problems reconciling quantum mechanics with observed behavior of some particles . . . but it turned out that the observations were not very accurate. You may recall that Einstein challenged some of quantum mechanics on this basis.

  You know, one does not ahve to agree with Dyson to find his ideas intriguing, and the level of half-witted vituperation against the man by people whose every statement demonstrates a howling ignorance of the topics they are syaing he is wrong on is what stuns me.

  Dyson has some interesting ideas on factors that may be contributing to global warming, including issues related to land management and topsoil. He is also right when he states that the current computer models are far from perfect, and do not explain some major observed climate phenomenon -- but the problem with that argument is that they are what we have -- and its hard to see wha we might feasibly get that is better. the weakness with arguing that we need to use more local data is that climate change is a very slow process (standby for a stupid comment from Sugerman) and to get the sort of local data that he argues for would mean decades of measurement -- since most does not already exist.

  One point that so many posters on this forum absolutely proved Dyson right about is that too many people are letting politics drive the discourse on Global Warming -- I see exactly the same behavior on the part of those who want to deny that it is happening (unlike Dyson) or that human activity is a contributing factor (again unlike Dyson.) Whay stuns me is how many jackasses there are, who fail to see how their complete refusal to learn the physics or engage in anything other than irrational ranting there are. A huge proportion of the posters on this forum simply attack anyone who asks hard questions on climate topics.

  And yes, I did intend the word Jackass to apply to some people.

  Grubert, you ask how respected Dyson is --- well Dyson was elected FRS by his peers, and on that basis it does seem that his fellow Physicists, not to mention a large number of scientists in other disciplines think he is an important figure and pretty first rate.

  Permalink Sunday, September 30, 2007 10:27 AM