Lichtgedanken 02

Editorial 51 02 | LICHT GEDANKEN Photos left: The Jena piece of the Stubenberg mete- orite (»Stubenberg M6«). The stone made of common chondrite weighed around 35 grams from which one piece was sawn off and provided for analysis. The light grey, slightly gleaming rock is surrounded by a deep black fusion crust – traces of its scorchingly hot passage through the earth’s atmosphere. Originally, it comes from the asteroid belt between Mars and Jupiter. Top left: Location of the find in a piece of woodland; Bottom left: The remaining piece of the meteorite with cut surface. Photo right: Dr Agnese Fazio and Dr Dennis Harries. When they’re not off hunting meteorites, the minera- logists analyse rock samples as here with a Raman microscope. in weight with a diameter of 70 cm be- fore entering the earth’s atmosphere,« Agnese Fazio recounts. »Much larger pieces must have hit the ground than what had been found so far,« says the 29-year-old junior scientist with expe- rience of hunting meteorites. In 2012, she was with a team from Pisa Univer- sity on an expedition to the Antarctic. The researchers there had discovered more than 100 meteorites in the space of two months. Meteorite hunt with a happy end After three days, Fazio returns to Jena. Harries continues to search. His frust- ration mounts, and his feet are hurting. He has now left the farmers’ fields whe- re searchers had a clear view, and was now combing through brambles in the dense wood. Still he finds nothing. But this would not be a good story if it did not have a happy ending: On 3 April, ten days after starting his search, Den- nis Harries notices an unusual-looking black rock on the side of a path, about the size of a ping-pong ball. »I knew immediately it was at least something unusual,« Harries recalls. As a precau- tionary measure, he photographs the site of the find before carefully lifting the stone out of the soft soil lined with pine needles and small twigs. When he has the stone in his hand, he knows that he has found a piece of the Stubenberg meteorite. What followed after the happy end, is part of everyday scientific life: the mete- orite was measured, sectioned and sub- jected to mineralogical analysis. »The stone is a common chondrite,« says Dr Harries. As a meteorite, the »Stuben- berg« is pretty unspectacular, he goes on. »Over 80 percent of all meteorites found on earth are made of this mate- rial.« Nevertheless, these stones, that are not found on earth (except as me- teorites), afford a glimpse into the deep past of our solar system. The meteorites come from the asteroid belt between Mars and Jupiter and they were created from the cloud of gas surrounding the sun in the early ages of the solar system, more than 4.5 billion years ago. They therefore consist largely of unchanged original matter from our solar system. nis Harries who works at the Chair of Analytical Mineralogy of Micro- and Nanostructures, and among activities, conducts research on meteorites. Ba- sed on the photographs and data on the weather situation that evening, it was possible to narrow the area in which the cosmic rock must have struck the ground very precisely. When the first pieces of the Stubenberg meteorite were found a few days later, Harries could not wait any longer in Jena. Together with his Italian colleague, Dr Agnese Fazio, he sets out for Bavaria. »The calculated scatter field comprised several square kilometres of farmland and woods,« Harries recalls. On the very day of their arrival, the 35-year-old discovers a tiny fragment of the mete- orite. »It was then that the thrill of the chase gripped me.« There followed a day-long hike. Metre for metre, Den- nis Harries and Agnese Fazio combed the area along with dozens of other re- searchers and amateur meteorite hun- ters – often watched sceptically by the farmers who were waiting to be able to plough their fields at long last. »According to calculations, the rock must have been around 600 kilograms Behind the Scenes