During my last trip to Berlin I took the S-Bahn to Potsdam Hauptbahnhof intending to take the uphill bus to Telegrafenberg. However the line only operates in the morning and the late afternoon transporting the employees of the science institutes up and down the hill. Eventually I took a taxi taking me to the guarded entrance of the Science Park. I told the man behind the counter that I wanted to pay a visit to the monument dedicated to my famous physics colleague. He smiled, stood up, and handed me a pound of paper information. Well documented I started my up-hill walk passing various information panels and institute buildings.
The Telegrafenberg got it's name from the mechanical telegraph that the Prussian government implemented in the first half of the 19th century. Following Napoleon's defeat and the Congress of Vienna in 1814/15 most of the old borders in Europe were restored with some noteworthy exceptions. Austria cleverly gave up its possessions on the Upper Rhine - note that on Napoleon's order the Breisgau with its capital Freiburg had already become "badisch" in 1806 - thus avoiding any future confrontation with France while Prussia acquired territories on the Lower Rhine including the coal-rich Ruhr district as well as the cities of Cologne and Coblenz. Thus the Prussians were assuming the Wacht am Rhein (The watch over the Rhine river) with respect to France.
|Königlich-Preußische Optische Telegrafenlinie from Berlin to Koblenz|
|Reconstructed Prussian optical mechanical telegraph station in|
Cologne-Flittard. The many signal arms enabled the transmission
of information-rich messages (©Superbass/Wikipedia)
With such a vast territory spanning from Königsberg in East Prussia to Aachen at the Belgian border fast transmission of information in the kingdom was a challenge. It took messengers on horseback three to four days to cover the distance between Berlin and Coblenz. Thus Prussia began the construction of an optical mechanical telegraph line in 1833 with 62 relay stations covering a distance of 550 kilometers between Berlin and Coblenz. The line started at Dorotheenstraße in Berlin, joined the Saint Anna Church in Dahlem, passed the miserable hill of the Schäferberg (shepherd's mountain!), went to the Telegrafenberg at Potsdam, and continued to Magdeburg's Saint Jean Church. After having gone through many more relay stations the line crossed some regions belonging to the Duchy of Brunswick, regained Prussian territory in Westphalia at Paderborn, and eventually reached Coblenz via the Cologne-Flittard relay. With the new installation the transmission of a telegram took 1.5 hours.
Karl Schwarzschild, the German astronomer. He was director of Potsdam's Astro-Physical Observatory from 1906 to his early death in 1916. In 1897, while in Vienna, he derived a formula to calculate the optical density of a photographic emulsion. Now the intensity of faint stellar light sources could be calculated with high precision from photographic measurements.
Whereas Einstein only gave an approximate solution for his field equations of general relativity around a single spherical non-rotating mass Schwarzschild while serving with the Prussian Army in Russia in 1915 calculated the exact solution. He wrote to Einstein: As you see, the war treated me kindly enough, in spite of the heavy gunfire, to allow me to get away from it all and take this walk in the land of your ideas. Needless to say, Einstein was impressed. Schwarzschild's calculations resulted in the famous Schwarzschild Radius being the size of the event horizon of a non-rotating black hole. Karl's son Martin became a distinguished professor of astronomy at Princeton University.
The Einsteinturm was built on the summit to house a solar telescope designed by the astronomer Erwin Finlay-Freundlich. The telescope supports experiments and observations to validate (or disprove) Einstein's relativity theory.
|The Einstein Tower seen from the front|
|Here it is seen from the back with the Big Refractor in the background|
|Together on earth and in space|