Dark Cosmos: In Search of Our Universe's Missing Mass and Energy

As Fermi Lab astrophysicist Hooper tells readers, the mass in any solid object, like a chair or a table, makes up only about 4% of the universe. The other 96% of the cosmos consists of invisible "dark matter" and "dark energy." Scientists have known about dark matter for a long time; some minigalaxies are composed almost entirely of the stuff. Dark energy is a more recent discovery: it's what seems to be pushing the universe apart faster and faster. Hooper explains why he and his colleagues have ruled out many leading candidates for the constituent particles of dark matter, like neutrinos. Today they are betting on particles called superpartners that bear Seussian names like sneutrinos, zinos and Higgsinos. Some researchers believe the missing mass may just be ordinary matter moving through the extra dimensions posited by string theory. Dark energy, which accounts for two-thirds of the energy in the universe, presents even more of a mystery. According to the author, some scientists have theorized that multiple universes may play a role. Hooper's clear presentation in very simple, jargon-free prose should appeal especially to young people just starting to get excited about the mysteries that still await them in science. (Nov. 1)