The Gravity of Math: How Geometry Rules the Universe

Science journalist Nadis and Tsinghua University mathematician Yau follow up 2019’s The Shape of a Life with an esoteric exploration of geometry’s role in explaining gravity and the structure of the universe. The authors chronicle advances in physics and mathematics alongside highly technical discussions of the theory and details behind those advances. An overview of how Albert Einstein combined Bernhard Riemann’s “ideas about curved space with [Hermann] Minkowski’s concept of four-dimensional spacetime” to develop a theory of gravity is challenging yet comprehensible. The historical perspective intermittently intrigues, covering how astrophysicist Karl Schwarzschild first posited the existence of black holes in 1916, and how mathematician Theodor Kaluza’s belief in “the presence of dimensions that have so far remained invisible” provided the premise for string theory. Unfortunately, discussions of more recent advances made by Stephen Hawking and Yau will be exceedingly difficult to grasp for most readers. For instance, the authors write of Yau’s efforts in the late aughts to figure out the “conditions that a definition of quasilocal mass should satisfy”: “The ‘correct limit’ realized at a point—after a procedure called normalization is done to obtain a nonzero limit—would, in fact, be the value of the stress-energy tensor at that point.” This is best suited to those with advanced knowledge of the field. (Apr.)