Astronomer Brad Schaefer of Louisiana State University, a maverick who unmasked the scientific inspiration for Sherlock Holmes and calculated the time of Jesus' crucifixion, is stirring things up again. He now suggests that the universe's expansion may have been fundamentally different in its earliest years from the way it is today, a finding that would rock astrophysics if confirmed.
His work builds on research first published in 1998, when two teams deduced that the growth of the universe is speeding up. Cosmologists now attribute this acceleration to dark energy, an undetected force that stretches space apart. To verify dark energy and understand how it works, scientists are trying to peer ever farther out in space and back in time. Schaefer realized that only a gamma-ray burst, the most powerful type of explosion ever observed, is bright enough to give us information about conditions near the edge of the visible universe, more than 13 billion light-years away.
Schaefer combined six different measurements of gamma-ray bursts to figure their distance and to probe how the universe has changed between their location and ours. He found evidence that dark energy is even more bizarre than his colleagues thought—not constant, as Albert Einstein imagined, but changing over time, so that the expansion of the universe might have sped up, slowed down, or even reversed at times. Schaefer and his colleagues may need years to confirm the results, however. "It's a hard theoretical game to play, even to understand how dark energy can be constant," he says, "since we don't really know what it is."