In March of this year the Harvard-Smithsonian Center for Astrophysics announced a breakthrough discovery, (the yet unconfirmed) existence of gravitational waves. As I wrote back on the day of its announcement, the discovery was thought to be "evidence to support [Einstein's] last untested prediction about the Theory of General Relativity." The existence of gravitational waves was viewed as proof of a period of inflation after the birth of our universe.
When it was announced, on March 17, the discovery had yet to be confirmed. Since then, other researchers have been skeptical that gravitational waves were viewed by the team and BICEP2 telescope in the South Pole. It may have all just been dust in the Milky Way.
Now the researchers themselves are hedging the discovery. Nature writes:
"In a paper published on 19 June in Physical Review Letters1, the BICEP2 collaboration, named after the South Pole telescope they used to look at a patch of the microwave sky, acknowledges that the foreground effect of dust in the Milky Way may account for a larger fraction than previously estimated — and possibly all — of what had appeared to be a signal from the dawn of time.
"In addition, presentations given earlier this week at a cosmology conference in Moscow, based on observations from the European Space Agency’s Planck satellite add fresh evidence that what BICEP2 could be entirely due to a confounding effect of dust."
Dust in the Galaxy can cause similar polarization as gravitational waves. And due to the lack of public availability, the researchers did not include information from Planck, the European Space Agency satellite, which according to Nature, has been doing scans of the microwave sky from 2009 to 2013.
Scientific critiques include those from Rafael Flauger at Princeton and Uroš Seljak at University of California, Berkeley. Despite these, and the researchers' own journal admission that dust could be a much larger factor than anticipated, a team member from BICEP2 still believes the polarization could have been from gravitational waves.
“We still say the data disfavour an all-dust interpretation,” Jamie Bock of JPL and Cal Tech said, according to Nature, “which is what we said on the topic of dust in March.” Though he also notes that the dust “appears to be somewhat higher than the pre-Planck models predicted.”
The Planck models will not be available until October. However, according to Nature, Jean-Loup Puget, a Planck astronomer of the University of Paris-Sud in Orsay, says that he and his collaborators will have a paper out in about six weeks explaining "that polarization from interstellar dust grains plays a significant role and might account for much of the BICEP2 signal that had been attributed to inflation-generated gravitational waves."