Scientists on the receiving end of big attention earlier this year when they announced some findings about the first moments of the early universe now say they might have been wrong in their conclusions.
Those conclusions about finding evidence of a long-theorized rapid expansion of the universe in the first fraction of a second after the Big Bang -- assumptions that garnered a lot of headlines -- may have to be revisited, they admitted.
A study led by researchers at the Harvard-Smithsonian Center for Astrophysics suggested detection of polarized light patterns in light still spreading out from the first moments of the universe was "smoking gun" proof, or at least strong evidence, of the so-called inflation theory, which holds the universe experienced an extreme expansion after it was less than a trillionth of a second old.
The findings constituted an identification of gravitational waves still rippling through space from the earliest moments following the Big Bang, they had announced in March.
The researchers have published the findings in the journal Physical Review Letters, but in their published article they've included an important caveat, admitting it's possible that what was detected may just have been ordinary starlight scattered and polarized by cosmic dust in our Milky Way galaxy.
"Since we submitted this paper new information on polarized dust emission has become available," the study authors, led by Harvard astronomer John Kovac, wrote.
Almost as soon as the research team made its initial announcement of its findings there was considerable debate and doubt as to what they had in fact observed -- gravity waves or something more mundane.
"I think the issue is still unresolved ... the issue being whether what they measured comes from gravity waves in the early universe or from the dust," said Alan Guth, a theoretical physicist at MIT who developed the inflation theory in the late 1970s. "I expect it to be resolved fairly soon."
Since the Harvard announcement, other researchers have published their own analysis of where the signals might have come from and what they might mean -- or not mean.
"We know that galactic dust emits polarized radiations," Princeton theoretical physicist David Spergal says. "We see that in many areas of the sky, and what we pointed out in our paper is that the pattern they have seen is just as consistent with the galactic dust radiations as with gravitational waves."
The resolution of the question may come within as soon as a few months when a competing research group working with the European Space Agency's Planck space telescope publishes the results of its work.
The Planck instrument scans more of the sky, and can detect more signals at more frequencies, than the telescope used by the Harvard-led team, Spergal noted.
While it may eventually prove the Harvard researchers right after all, they may have jumped the gun in their initial release of their findings, he said.
"I think, in retrospect, they should have been more careful about making a big announcement," he said.
