Black holes on the Russian Front

A short story of a scientist soldier

Honored Mr. Einstein,
In order to be able to verify your gravitational theory, I have brought myself nearer to your work on the perihelion of Mercury, and occupied myself with the problem solved with the First Approximation. Thereby, I found myself in a state of great confusion. But I was able to find the following results. It is an entirely wonderful thing, that from one so abstract an idea comes out such a conclusive clarification of the Mercury anomaly.
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.

Letter from Karl Schwarzschild to Albert Einstein on December 22, 1915 on The Eastern Russian Front.

Karl Schwarzschild wrote this letter to Einstein while he was a soldier fighting on the Eastern front during the first world war on the 22nd of December 1915. It was on that day, under the heavy gunfire as he states, that he was able to find, for the first time ever, an exact vacuum solution to the Einstein Field Equations ( EFE ), which are the equations Einstein derived that same year to describe the curvature of spacetime. The EFE are highly complicated equations. In mathematical terms, they are a set of 10 non-linear partial differential equations that cannot be solved analytically. Even Einstein himself couldn’t solve his own equations at first, he only found an approximate solution to the equations. Schwarzschild however, found a trick to this problem, he assumed spherical symmetry of the metric ( “spacetime” ). After all, stars and planets are “almost” spherical, so the spacetime they bend has to have this spherical symmetry.
The exact solution, known as the Schwarzschild metric, describes how spacetime is bend around a spherically symmetric object, like planets, stars, and even black holes. This was the birth of the modern concept of a black hole, a massive dense point in space that even light cannot escape, and it shows up in the metric through a singularity, that is when the metric blows up ( becomes infinite ). However despite the theoretical prediction of black holes his own solution showed, Schwarzschild disbelieved in them ( although the concept back then was not put forth ), calling them a physically meaningless solution.

Why was Schwarzschild on the Russian Front anyway ?

Schwarzschild was a respected scientist in the scientific community, having served great amount of work in astronomy and mathematics. From a professor and the director of the observatory of Göttingen, to a professor and director of the observatory in Potsdam, Schwarzschild earned the most prestigious title any astronomer can get in Germany. This secured him a high government position in his life, later being elected to the Berlin Academy of Science.
Schwarzschild carried over into political life the unitary concepts that guided his scientific life.
On the outbreak of war in August 1914, he volunteered, himself, for military service, feeling that loyalty to Germany should come ahead of professionalties and his personal background as a jew. After an initial delay, because of his high government position, he was accepted and placed in charge of a weather station in Namur, Belgium. Subsequently he was commissioned as a lieutenant and attached to the headquarters staff of an artillery unit, serving first in France and later on the Eastern front. His assignment was to calculate trajectories for long-range missiles; a communication to the Berlin Academy in 1915 (not published until 1920 for security reasons) dealt with the effect of wind and air density on projectile. It was there where he found the famous solution, the solution that was named after him.
Unfortunately, it wasn’t long until the atrocious war got to him. He contracted an illness while in Russia called pemphigus, which is a rare autoimmune blistering disease of the skin. For people with this disease the immune system mistakes the cells in the skin as foreign and attacks them causing painful blisters. In Schwarzschild’s time there was no known treatment and, after being invalided home in March 1916, he died two months later at the age of 42, not knowing that his work will lure scientists to the depth of knowledge for the centuries to come. (1) (2)