Craig Hogan was hooked on astrophysics the minute he learned that remnant heat from the Big Bang was still detectable. His wide-ranging contributions to the field include the co-discovery of 'dark energy' — the mysterious force behind the acceleration of the expanding Universe. But he hopes that future experiments will reveal an as-yet undetected dimension of the Universe. See CV

“Craig has forged unusually original and versatile theoretical insights into astrophysics,” says Martin Rees, Hogan's PhD adviser at the University of Cambridge, UK. “If you look at any number of subjects — from dark energy to how the Universe began — you'll find the earliest papers are from Craig.”

After postdocs at the universities of Cambridge and Chicago and at the California Institute of Technology in Pasadena, Hogan helped to build the first theoretical group at the University of Arizona's Steward Observatory. There, he learned the inner workings of telescope-based experiments as they applied to theory projects.

Hogan eventually joined the physics and astronomy department at the University of Washington in Seattle, where it was easier to bridge his interest in those two fields. Despite the clouds and mountains, Washington had a telescope large enough to survey supernovae, key to detecting dark energy. Hogan plays down the discovery. “The tension between the age of the Universe and the velocity of the galaxies had suggested a cosmological constant for a long time,” he says. The real surprise, he adds, was how well the experiment actually worked.

Hogan's research focus now includes proposed space-based experiments such as the Laser Interferometer Space Antenna (LISA), designed to detect gravitational waves in space. “So far we've turned snapshots of the Universe into a silent movie,” says Hogan. “Detecting gravitational waves would be like adding a soundtrack — and that is potentially much more transformative to science as a whole than discovering dark energy.”

As director of Fermilab's Center for Particle Astrophysics, Hogan will push for LISA as well as for other new ways to explore the physics of gravity and space-time. Fermilab will need a new focus once the Large Hadron Collider in Switzerland makes the lab's Tevatron particle collider obsolete. “Fermilab is the premier high-energy physics lab in the United States,” says Hogan, “and gravity is the one force of nature it hasn't yet studied.”