Einstein understood the importance of a space with positive curvature, as proposed by Schwarzschild several years earlier. The universe, according to general relativity, may be finite, but like the surface of a ball, that is, without boundaries.
Einstein understood the importance of a space with positive curvature, as proposed by Schwarzschild several years earlier. The universe, according to general relativity, may be finite, but like the surface of a ball, that is, without boundaries.