The stuff stars are made of: University of Kassel creates interstellar matter in the laboratory

Temperature differences of several thousand degrees and vacuum: Very special molecules are created under extreme conditions. These conditions only exist in space - and soon in a laboratory at the University of Kassel. At the start of the winter semester, the new Laboratory Astrophysics department began its work. It closes a gap in the university's offerings. Unlike the other natural science subjects, astrophysics has until now only offered a theoretically oriented course of study. The instruments for the laboratory at the Oberzwehren site will be delivered at the beginning of February 2013, and the laboratory is scheduled to go into operation soon thereafter.

Matter will then be produced there under conditions that otherwise prevail in interstellar space. "We are investigating the complexity of organic molecules in space," says Prof. Dr. Thomas Giesen, who heads the research group. "This is how we want to explain how stars form and decay."

Instead of randomly looking for previously unknown particles in space, the Kassel scientists are taking the opposite approach. They generate molecules in their apparatus for a few microsecondsthat do not occur on Earth under normal circumstances and study them spectrally. The spectral analysis method can be used to determine how certain molecules absorb light; this behavior is recorded in a so-called molecular spectrum. "The molecular spectrum of a substance is then like a DNA imprint," Prof. Giesen explains the meaning of the method. These specific patterns are also found in electromagnetic radiation, such as that emitted by the molecular clouds of nascent or dying stars in distant galaxies. This radiation is recorded by special telescopes - making it possible to check whether the molecules produced in Kassel are present in space or not. If the researchers find a match, they can draw conclusions about chemical processes that take place there. To do this, the Kassel astrophysicists are working together with the SOFIA stratosphericobservatory, a NASAflying telescope installed on board a converted Boeing 747.

The meaningful radiation reaches Earth in the terahertz wavelength range. So far, studies of the terahertz range in similar quality have only been carried out in Germany in Cologne, and now also in Kassel; worldwide, only about 15 research groups are doing this. The scientists are strongly networked. The researchers at the University of Kassel, for example, form a network with colleagues from Cologne, Paris and Saskatoon (Canada) to gain insights into the origin of celestial bodies; for this purpose, they use the SOLEIL particle accelerator near Paris, for example. "Ultimately, the question is also how planets form in the sequence of stellar births and whether our Earth is a unique exception. And we expect clues as to where the interface between inanimate matter and life lies," Prof. Giesen hopes.

Prof. Giesen expects his team to produce two to three novel molecules per year in the lab. He estimates that more than half of the molecules produced in this way will probably later be detected in space. In the past, the astrophysicist has already been involved in the discovery of more than 20 molecules in space.

Prof. Dr. Giesen (52) was most recently an adjunct professor at the University of Cologne. Born in Duisburg, he studied physics in Cologne, where he received his doctorate in 1992 and his habilitation in 2001. Giesen also worked at the University of California, Berkeley/USA, and at the Bergische Universität Wuppertal. He is a scientific member of several space missions.

Research projects and further information at www.uni-kassel.de/go/labastro.

Info    Prof. Dr. Thomas Giesen
University of Kassel
FB 10 - Mathematics and Natural Sciences
Institute of Physics
Tel.: +49 561 804-4775
E-mail: t.giesen[at]physik.uni-kassel[dot]de