ORSAY, France, Jan. 31 (UPI) -- Scientists have countered a controversial 2014 study that claimed to find evidence of the rapid expansion of the early universe, upending what was considered the best evidence of the Big Bang theory.
Scientists working with the European Space Agency's Planck satellite, which observes the Cosmic Microwave Background, said the apparent gravitational waves that were thought to be caused by cosmic inflation were instead space dust.
In March, researchers from the U.S.-led BICEP2 project at the South Pole Station said the gravitational waves were evidence of the "first big tremors of the Big Bang" about 13.8 billion years ago.
The BICEP2 team concluded the pattern they observed in polarized light in a small patch of sky originated in the primordial gravitational waves that astronomers believe would be present if cosmic inflation had occurred.
But in September Planck scientists revealed new data that showed polarized dust emissions were more widespread than previously thought.
Planck researchers teamed up with BICEP2 scientists and used the latest data from the Keck Array, also in the South Pole, to conduct a joint study, which found the same effect can be produced by interstellar dust in the Milky Way, our own galaxy.
"So, unfortunately, we have not been able to confirm that the signal is an imprint of cosmic inflation," Jean-Loup Puget, principal investigator of the HFI instrument on Planck at the Institut d'Astrophysique Spatiale in Orsay, France, said.
Researchers note, however, that cosmic inflation is still an open question.
"This [most recent] analysis shows that the amount of gravitational waves can probably be no more than about half the observed signal [from the 2014 study]", says Clem Pryke, a principal investigator of BICEP2 at University of Minnesota.
"The gravitational wave signal could still be there, and the search is definitely on."