Saturday, October 17, 2009

Minerals and meteorites at the Messe

Today was yet another cold, drizzly day in Freiburg, so we stuck close to home and walked to the Messe (exhibition hall) for a gem and mineral show, where we helped revive the global economy. The winner of the Best Salesmanship Prize was surely the proprietor of a meteorites display, who heard us speaking English and leapt up to show us a photo of Meteor Crater in Arizona. Thereupon followed a detailed discussion, auf Deutsch, of various types of meteorites, their origins, chemical composition, crystalization patterns, how quickly or slowly they cool, what happens to Earth rock when a meteorite plows into it, what happens to the meteorite when it hits the earth, and what types of meteorites tend to be found in what parts of the world.

We're now the proud owners of a small sample of Muonionalusta meteorite, first discovered in Sweden in 1906. Formerly part of an asteroid core that shattered billions of years ago, our thin slice of iron octahedrite has crystalization patterns that show it cooled at a supremely slow rate in the vacuum of outer space--on the order of one degree per thousand years. About 800,000 or so years ago, it fell to the Earth north of the Arctic circle in a sizable meteor shower, got pushed around for a while by glacial activity, and then sat unceremoniously buried in glacial sediment until the invention of the metal detector and the arrival of intrepid meteorite hunters.

Also new to our collection: a 70 million year old petrified shark tooth from Morocco (hardly rare, but monstrously cool) and some nifty cubes of Spanish pyrite (call us fools).

On the way home, we navigated through the Freiburg Mess'--Freiburg's annual Fall fair--outside the Messe. During a brief pause in the rain, Elias and Stefan saw a double rainbow from the top of the Ferris wheel.

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