An enthusiastic update on the search for the materials that make up the universe.
From Newton’s gravity to Einstein’s relativity, explanations of how matter, energy, time and space behave represent a dazzling triumph of human genius. However, astronomer Gates points out in her first book, they don’t explain everything. In the 1930s, scientists studying stars and galaxies discovered that they were moving faster than could be accounted for by the gravitational pull of nearby visible matter. Most mass in the universe must be invisible “dark matter,” they concluded. Researchers and theoreticians had been mulling this over for decades when, in 1998, astronomers discovered that expansion of the universe, which Einstein predicted and everyone took for granted, was accelerating. No one had predicted this, and explaining it required immense amounts of what inevitably became “dark energy.” It turns out that the matter and energy scientists have studied for centuries make up four percent of the universe. The rest remains a mystery. Gates paints a striking picture of astronomers’ efforts to solve this dilemma, emphasizing their use of a fascinating phenomenon she calls “Einstein’s Telescope.” Gravity, Einstein explained, distorts space, and this deflects the path of any light passing nearby. He theorized—and 50 years later astronomers verified—that when an object lies between Earth and a distant light source such as a star or galaxy, that object’s gravity acts as a lens, magnifying the source’s image. Gates vividly describes the avalanche of new information revealed by “gravitational lensing.” Astronomers now measure the movement and makeup of galaxies far across the universe, but lensing also reveals planets orbiting stars in our galaxy and details of peculiar objects such as black holes, neutron stars and brown dwarfs.
Splendidly satisfying reading, designed for a nonspecialist audience.