The 4-Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality

Oneworld Publications, 2011 The book's namesake comes from the scientific confusion over how ordinary matter makes up only four percent of the mass energy in the universe, with the rest consisting of mysterious dark matter and dark energy that are both invisible and almost impossible to detect. It is due to dark matter that galaxies are able to keep their shape, with the mass of dark matter creating enough gravitational force to hold the stars that make up a galaxy together. Dark energy, however, is a substance or force responsible for the accelerating expansion of the universe over time. The significant focus of The 4 Percent Universe is on the developments of astronomical science in the 20th century, including the formation of the expanding universe theory by Edwin Hubble in the 1930s. This model, when used in conjunction with Albert Einstein's general relativity helped in the creation of the Big Bang model and the later discovery of the cosmic background radiation in the 1960s. In following this history, Panek also discusses the flaws and missing pieces in the theories and the quest by two major scientific groups to discover the reason for the expansion of the universe not matching the models as expected. The book discusses the science behind the idea of dark matter being made up of weakly interacting massive particles and how scientists tried to determine the existence of dark energy from the 1990s and onward. The two groups involved in this research were the Supernova Cosmology Project headed by Saul Perlmutter and the High-Z Supernova Search Team headed by Brian Schmidt, both of which were involved in pioneering the use of Type Ia supernovae as standard candles for determining the variation in the universe's rate of expansion over its history, which in turn allows prediction of its future expansion.. Soft cover. Fine.