Dazzle or dust?
Unpredictable glow of galactic dust could undermine biggest cosmological discovery in years
DUSTY DATA The BICEP team used one map (left) to estimate the effect of galactic dust on the polarization of light across the sky (red denotes stronger polarization, blue weaker). Raphael Flauger reconstructed a similar map (right) from other sources showing that dust could account for much more of the signal detected by the BICEP team.
J.-P. Bernard/Planck Collaboration; R. Flauger
On March 17, Lloyd Knox, a cosmologist at the University of California, Davis, joined scientists around the world in celebrating a Nobel Prize–worthy discovery. That day researchers from the Background Imaging of Cosmic Extragalactic Polarization project announced that their telescope at the South Pole, BICEP2, had detected a subtle twirling pattern imprinted on light that had traveled across the universe for 13.8 billion years.
The measurement was impeccable, the implications profound. The imprint, the BICEP researchers said, could be made only by gravitational waves, ripples in space triggered when the universe explosively kick-started its expansion a split second after the Big Bang. If the results held up, they would serve as the first direct evidence of that rapid expansion, known as inflation, which was predicted in 1981 to explain the uniform structure of the cosmos (
