Physicists are Backing Away From the Biggest Discovery of the Century

By Sarah Zhang on at

Back in March, a group of physicists announced the first direct evidence of the Big Bang in a splashy press conference followed by Nobel prize forecasts and champagne. But scientists have since questioned the discovery, and a new paper suggests the signal detected was not evidence of the Big Bang but instead largely, if not entirely, from interstellar dust. Oops.

Earlier this year, scientists using data from the BICEP2 telescope in Antarctica said they found a pattern called "B-mode polarisation" in the cosmic microwave background, which is radiation left over from the formation of the universe. These swirls matched the patterns thought to be made by primordial gravitational waves, which had been predicted but never seen before.

BICEP2 seemed to offer proof of the existence of primordial gravitational waves, and by extension, the Big Bang. Woohoo! Applause! Nobel!

But there is much more prosaic explanation for those patterns too: dust. The BICEP2 scientists tried to account for this by using several known models of dust in space, including a preliminary map from a Powerpoint presentation given by a researcher working with the European Space Agency's Planck space telescope.

Now, Planck scientists have published their full map of interstellar dust, and there is more contamination than BICEP2 had accounted for. How much of BICEP2's signal actually comes from dust is still a matter of analysis; the teams are working together and expected to publish something in November.

There's still some hope that BICEP2 detected more than dust, but those celebrations back in March were just as likely premature. Science by press conference is flashy, but it obscures how science really works: slowly, in fits, with lots of back and forth. [Quanta]

Top image: BICEP2 Telescope. Amble/Creative Commons