Ever since the Big Bang nearly 14 billion years ago, the universe has been expanding. Astronomers once believed this growth spurt would gradually slow down, but in 1998 they discovered that distant galaxies were actually moving away from one another faster than ever. Instead of hitting the brakes, the universe is flooring the gas pedal.
A new project representing 23 scientific institutions is investigating this mysterious cosmic propellant, called dark energy. The centerpiece is the Dark Energy Camera, which will be operational in July after it is installed in the telescope at the Cerro Tololo Inter-American Observatory in Chile.
The “lens” of the 5.5-ton camera consists of 62 digital sensors calibrated to detect the light trails of celestial bodies moving away from Earth. Astronomers will collect data on the acceleration of 300 million galaxies to study the properties of dark energy—and why the universe is exceeding its speed limit.