Founder’s Day 541
Stargazing and stargazers at LMU
LMU celebrates its 541st birthday on 28. June. Astrophysicist Professor Ralf Bender gives this year’s lecture – on “The Invisible Universe”. In LMU’s history, however, astronomy has been anything but invisible.
Spiral galaxy, as seen from Wendelstein Observatory.
In 1611, while observing the Sun from the tower of the Jesuit Church of the Holy Cross in Ingolstadt, Christoph Scheiner (1573 or 75-1650), a member of the order and professor at the town’s Hohe Schule – the College of Higher Learning that would later become LMU – made a significant discovery:
Seven or eight months ago, a friend and I turned our telescope, the instrument that I still use, which magnifies the image of an object by 600- or 800-fold, on the Sun. We wanted to compare its optical size with that of the Moon, and found that the two were very nearly equal. While we were so engaged, we noticed in the Sun several somehow darkened spots, like black drops …
Together with his assistant Johann Baptist Cysat, and at around the same time as Galilei, Scheiner had discovered sunspots, irregularly shaped solar regions that are cooler and radiate less energy than their surroundings. It is now clear that they arise at points on the Sun’s surface where intense magnetic fields restrict the flow of energy from the underlying convective zone.
Actually, Scheiner is probably better known for his pioneering work in optics. Among other things, he built so-called helioscopes, telescopes designed to project part of the Sun’s light onto a sheet of white paper or card, thus allowing it to be observed without risk of injury to the eye. This kind of instrument can be used to monitor and map the changing distribution of sunspots.
Leaders in observational astronomy
Munich’s Scheinerstrasse, located in the Bogenhausen district of the city, is named after the co-discoverer of sunspots. And on Scheinerstrasse, right beside the present Institute of Astronomy and Astrophysics, one can find what is left of the former Royal Observatory, erected in the years 1816-1818. In the context of a reorganization of the State Science Collections undertaken in 1937/38, the Observatory was integrated into the Faculty of Natural Sciences at LMU, and became the University Observatory. Here one can still admire the refractor designed by the glassmaker and inventor Joseph Fraunhofer (1787-1826) – in its day the finest telescope in the world. It was used to initiate a long-term program of observations of Halley’s Comet and, more importantly, to continue Fraunhofer’s epoch-making spectroscopic observations of bright stars, which inaugurated a field of research that is still central to modern astronomy.
Johann von Lamont (1805-1879) was appointed Director of the Observatory in 1835, and became Professor of Astronomy at LMU in 1852. A native of Scotland, he made notable contributions to observational astronomy, but is chiefly remembered today for his work on terrestrial magnetism, geophysics and meteorology. Two craters, on the Moon and on Mars, bear his name.
Astronomical research has never been a simple matter of stargazing. Whether at the Hohe Schule in Ingolstadt or in 19th-century Munich, astronomy has always thrived on the interplay between theoretical intuition and technical innovation. From a technical point of view, one of the most significant developments for “watchers of the skies” at LMU was the incorporation into the University of the Solar Observatory on the 1800-m Alpine peak of Wendelstein in 1949. This establishment had been set up in 1941 to study the influence of solar activity on radio communications – primarily in military contexts. After the war, attention turned to the investigation of plasma physics on the Sun, based on observations of phenomena such as solar flares. However, the increase in light scattering caused by the rising concentration of particulates in the atmosphere eventually made ground-based solar observations impossible. The focus then shifted to night-time observations, which were carried out mainly with an 80-cm telescope that was installed on the mountain in 1989.
Munich has remained a prime address in the field of astronomy – thanks to the concentration of expertise to be found in the “Universe” Excellence Cluster, the extensive involvement of the University’s observatories in collaborative projects with the great international observatories around the world, and, not least, the new 2-m telescope deployed on the Wendelstein site in 2012. Financed by the State of Bavaria and the Federal Ministry for Research and Technology, the new instrument is named after Fraunhofer. Its 2-m main mirror, with a total focal length of 15,600 mm, provides high-resolution views of objects in the depths of the Universe. Professor Ralf Bender, Director of the University Observatories, mentions some of its capabilities: “Not only can we now analyze galaxies and galaxy clusters in great detail, the new telescope significantly enhances our ability to study the dark components of the Universe and the growth of supermassive black holes. In his lecture on “The Invisible Universe: Matter and Energy Beyond the (Present) Limits of Physics“, to be given (in German) on Founder’s Day, Prof. Bender will discuss the observational evidence for dark matter and dark energy. These mysterious phenomena represent one of the greatest challenges that physicists and cosmologists face today. They are also at the heart of the University Observatories’ future research program – with which the history of astronomy at LMU enters a new era.
- For further information on the history of LMU, consult the richly illustrated volume: Die Ludwig-Maximilians-Universität – Geschichte und Gegenwart