Der Triumph der Relativitaetstheorie: Bestaetigung der ART
Cosmological Considerations in the General Theory of Relativity, Sitzungsberichte der Preußische Akademie der Wissenschaften, Berlin 1917, reproduction
In 1917, Einstein introduces new field equations for the General Theory of Relativity. They include a
cosmological constant and their solutions describe a closed universe of constant size. Einstein hopes to exclude the existence of a universe that contains no mass and yet still contains inertial forces. This universe would stand in contradiction to Mach’s principle.