It was a claim so bold, it could not go unnoticed. In March, American scientists using the BICEP2 satellite reported they’d found evidence of primordial gravitational waves left over from the Big Bang. If confirmed, these cosmic ripples would provide strong support for the theory of inflation—a short but explosive spurt of growth that launched the universe.
With the international press blaring news of the discovery (see also here, here and here), astrophysicists around the globe quickly split into two camps. Many cheered the findings. But skeptics, including several supporters of inflation theory, challenged the findings, raising questions about possible distortions in the data.
“Unfortunately, we have not been able to confirm that the signal is an imprint of cosmic inflation,” said Jean-Loup Puget, a member of the European Space Agency’s Planck satellite team.
A joint study released Friday from BICEP2 and the European Space Agency’s Planck Satellite team shows these signals were, in fact, distortions. The culprit: interstellar dust in the Milky Way.
As early as last spring, BICEP2 team leader John Kovac acknowledged dust might account for a portion of the signal detected. While confident of the initial findings, Kovac told a gathering at the 2014 World Science Festival event Ripples From the Big Bang he was eager to see what light new Planck data could shed on the BICEP2 findings.
But supporters and skeptics alike insist a failure to detect gravitational waves is not a failure for science.
“Had the astronomers actually seen gravitational waves…generated just after creation, that would have been spectacular, of course,” said physicist and World Science Festival co-founder Brian Greene. “But the whole episode is a triumph for science. Scientists put forward results, they are debated by the community, and in the best case scenarios, new observations or new experiments settle the issue.”
The paper, “A Joint Analysis of BICEP2/Keck Array and Planck Data,” has been submitted to the journal Physical Review Letters. Meantime, supporters of cosmic inflation are not giving up. NASA’s Brendan Crill, a leading member of both the Planck and BICEP2 teams, insists “gravitational waves might still be hiding in the data,” adding, “the search is definitely on.”