Tomorrow our semester starts back, which means I have to return to the classroom. It is always hard to go back after a semester break. For me the dread is not because of teaching - necessarily - but because of all the useless wastes of time that accompany a semester in term. Faculty meetings rise to the top of the hate list. Perhaps I'll do more blogging during faculty meetings this time around... I think that helps.

Anyway, this semester I'm teaching a course on the environment, specifically about the cyclic processes and systems that operate on or around Earth's surface and define our world as habitable. Earth is a unique planetary system. Compared with every other planetary body we know much about, Earth is astoundingly rich in chemical and physical complexity. Earth has liquid oceans and a thick atmosphere of gases that are chemically reactive and trap thermal energy from the Sun. Earth has a vigorous system of plate tectonics that drives a factory conveyor belt pumping out new land and fresh carbon dioxide. Earth has a churning outer core above a shining inner-core nugget of electrically-conductive iron; a self-contained dynamo driven by gravity, heat and momentum that exerts a protective planetary barrier of magnetism that screens out most particle radiation from space. Earth has a large Moon that steadies its axis of rotation... and our seasons. Earth has spawned an astounding assortment of self-replicating machines - life - that collectively transform and continually modulate the planet's climate and the long term atmospheric composition.

I try to teach my students a useful perspective when addressing environmental issues; that of a planetary geologist. That is the reason for this blog's name. In the classic novel Dune, planetologists were appointed by the Emperor of the Known Universe to study whole worlds, to figure out what interlocking attributes of a planet contribute to its makeup and surface conditions, and ultimately to determine how a planet can be most usefully and sustainably managed to optimize habitability. Aside from the Emperor stuff, that's basically how I look at the study of planets. What kinds of planets can exist, with what weird variety of surface compositions and conditions? What subset of those possible planetary profiles are capable of supporting natural self-replicators? Once evolved, what influences do self-replicators exert on their birth world... and ultimately, the universe at large?

In my environmental systems course I have to address a smaller scope, by necessity of time and the catalog course description. Mostly I focus on how Earth formed, how climate works, and how human activities can perturb planetary-scale processes in tangible, measurable ways. It's never clear how much of that gets across to students in one semester. Probably not much.

Well, if students are going to get something from my courses, it might as well be something useful. The first lectures I give, in most of my introductory courses, deal with skepticism. Skeptical thinking and rational evaluation of evidence are two things I care very much about, and which get a lot of coverage in my blog posts here. Looking critically at evidence and evaluating claims using skeptical inquiry appear to be the only tools available for reliably solving problems. When applied to certain problems, we call that practice science. When applied generally, we call it not being stupid. Failure to apply this practice results in all sorts of terrible, stupid, harmful things... such as fundamentalism, creationism, science denial, conspiracy theories, the anti-vaccination movement, pyramid schemes, psychic predictions, homeopathy, 'recovered' memories, abduction by UFOs, haunted houses, and children being beaten to death during exorcisms. Being gullible kills. Skepticism saves lives.

In the environmental arena gullibility is no less deadly. Corporations lie and propagandize to hide pollution, or the harm it causes. Governments choose ideology over pragmatism, leading to warped and destructive public policies - and wars - that weaken our national security and place our fate as a civilization in the hands of people still motivated by Bronze Age tribal disputes... both in Middle Eastern theocracies and in American bully pulpits. People vote for politicians who reject facts that disagree with faith. Well-meaning young people march against genetic engineering, yet are ignorant of both genetics and engineering, or the fact that they most of them wouldn't exist without agricultural and medical science.

I can't do much about most of those problems, but I can try to diffuse a tiny bit more skepticism and rationality into the people who sign up for my courses. That's a goal of this blog, too... although the Planetologist allows himself to be much more in-your-face than Prof. Haas is ethically supposed to be. Nonetheless, every time I teach a course on the environment, or on the evolution of life through geologic time, or on the geochemistry of life's origins, I try to start off with a short primer on baloney detection and gullibility avoidance. The skeptical community gets plugged at that point (e.g. The Skeptic's Guide to the Universe, Bad Astronomy, Skepchick, and Skepticality, for starters), but that's only appropriate. They're the ones who got me into this media-skeptic thing in the first place. Thanks for that, by the way.

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Comment by Planetologist on January 6, 2009 at 12:09pm
Thanks, Scott, for the Sagan comparison... he's a personal hero of mine, and his Cosmos series was one of the critical factors, I think, that led me into becoming a scientist. His are big shoes, though... and I'm nowhere close to worthy enough to even try them on for size.

Clarence... I do a lot of work with trace elements, including rare earth elements, lead, uranium, cadmium, arsenic, and others that are much more harmful than Hg. Heavy metal poisoning is like radiation poisoning, in that dose matters. A tiny dose is literally unavoidable, just by virtue of living in the world. Thimerosal contains Hg, but the amount delivered in a typical vaccine dose - though today most vaccines don't even contain this harmless agent anymore - is far below the level at which a measurable effect would be observed in the body. Eat a couple of fish and you'd get more Hg. Also the form of Hg in thimerosal is not particularly bioavailable, in contrast to methylmercury and dimethylmercury, which are the most common forms of Hg encountered in fish... and which are far more bioavailable and toxic. Thimerosal as once used in vaccines is not dangerous, in all practical considerations... not vaccinating, or using vaccines without preservatives, are far more dangerous. Amalgam is more unclear... I've read papers that indicate some Hg leaching from tooth amalgam is possible... but it's complicated by diet and other conditions. In any event I think most fillings today use ceramics, at least in the developed world. But I'm not a dentist, so I can't quote figures on that.

Fluoride is only poisonous in sufficient dosage... just like anything else. At very low concentrations F in water presents no measurable health risk, but at higher concentrations can cause a condition known as fluorosis, which weakens apatite in bones and teeth. The mineral apatite can include F in its crystal structure, where otherwise it would include hydroxide (OH) or chlorine (Cl). Too much F warps the crystal structure relative to hydroxyapatite (that containing OH), the normal form of apatite in teeth and bones, and enough F can be deadly. I know of cases where volcanic eruptions released enough HF gas (along with HCl gas) to cause extreme fluorosis in nearby cattle herds, warping their bones over time and killing them most hideously. But those are extreme cases. In fluoridated water the F concentration is very low, about 1 ppm, and doesn't appear to cause any measurable health problems.

I did a literature search for any references to fluoride and villi. One paper from 1995 (Sondhi et al., FLUORIDE v. 28(1), pp. 21-24) found an association between intestinal damage and F in mice, but at F intake concentrations of 100 ppm... which is 100 times the normal treated-water dosage. Another study from 1998 (Tertrin-Clary et al., FEBS LETTERS v. 422(1), pp. 123-128) looked at the activity of protein kinase-C activity in stem villi vessels from human placenta, versus F, and found no adverse effects. A third study from 2007 (Bhatnagar et al., FLUORIDE 40(1), 55-61) found an association between damage to intestinal villi in fish and elevated F exposure... but again, they used F concentrations that were about an order of magnitude above public water supply levels. Those are the only three papers I could find on that topic, and none of them address dental villi. If there are other papers on this issue I'd be interested to get the references.
Comment by Clarence Dember on January 6, 2009 at 1:56am
Hi Professor Haas. Dune is an great series of books dealing among other things with the evolution of a planet. (Max Von Sydow is a favorite actor of mine. Dune, What Dreams may come...)

Although there has been much benefit from vaccines over the years, there is no benefit to allowing mercury to find it's way into my tissues- be it as a preservative such as thimerosal or an amalgam such as the ones of silver and mercury found in some dental fillings.

Fluoride is also poison, and has been used to kill rats, as well as bacteria on your teeth. Dentists think it's necessary. I don't agree. It poisons the tooth root and loosens the grip of the villi which fasten the teeth to the jaw bone by exacerbating oral infections caused by plaque gingivitis and tooth decay from dietary sucrose.
I have a surgically implanted port to decompress an odontogenic kerato cyst of the mandibula. I won't be needing any fluoride, pork or mushroom fungus in there.
Comment by Scott on January 4, 2009 at 10:22pm
I imagined myself being in your class and listening to this lecture and I felt amazed. Talk about science and rationality is for me, often a source of wonder. You remind me of Carl Sagan... funny, fascinating but profoundly and flagrantly enlightening.

Looking forward to your next post.

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