Chapter 2 opens with theoretical physicist Albert Einstein opening a letter from Karl Schwarzschild that contains “the first exact solution to the equations of general relativity” (37). Einstein is shocked because Schwarzschild was able to calculate how the mass of a star changes the space and time around it. Einstein responds to the letter, but Schwarzschild is already dead.

Schwarzschild’s calculations are accurate for ideal stars, but it troublingly indicates that for collapsing stars space-time would tear apart: “The star would go on compressing and its density would increase till the force of gravity became so powerful that space would become infinitely curved, closing in on itself […] permanently cut off from the rest of the universe” (39). This phenomenon is called the Schwarzschild singularity.

When Schwarzschild initially makes this discovery, he can hardly believe it because it defies all known laws of physics. While fighting in WWI, Schwarzschild obsesses over the dark hole of the singularity. Later, he is diagnosed with pemphigus, an autoimmune disease that may have been triggered by a gas attack and that ultimately kills him. Schwarzschild volunteered to fight for Germany in WWI, even though he was 40 years old and the director of the Astrophysical Observatory in Potsdam.