|A piece of the Milky Way sky. Image courtesy of M. Blanton and SDSSIII.|
From the DOE Office of Science’s In Focus, April 12, 2011
Is there a mysterious source of energy driving the expansion of the universe, or is our understanding of gravity incorrect? DOE lab scientists use data from observations and images of the night sky to find out.
Since the 1920s, scientists have known that the galaxies—long thought fixed and unmoving—were actually receding deeper into the cosmos. In fact, we now know from observations of Type 1a supernovae that distant objects are speeding faster and faster away from us as the universe expands. That’s because, not only is the universe expanding, it’s expanding at an increasing rate. Scientists at Fermi National Accelerator Laboratory (Fermilab), Brookhaven National laboratory (BNL), SLAC National Accelerator Laboratory, and Lawrence Berkeley National Laboratory (Berkeley Lab) are eager to find out why. Recent observations by SLAC scientists and the Sloan Digital Sky Survey may provide an answer.