Earlier this spring, an astronomy group called Bicep announced that they had discovered gravitational waves in the sky that were echoes of the Big Bang. But the study has been increasingly called in to question by scientists who claim that interstellar dust could have produced the ripples instead.

A recent study led by Jean-Loup Puget of the Astrophysical Institute in Paris confirmed last week that there was a significant amount of dust directly in Bicep’s view, contaminating their results. The data was gathered from the European Space Agency’s Planck satellite and showed a large amount of cosmic dust that could have been mistaken for gravitational ripples.

“We show that even in the faintest dust-emitting regions there are no ‘clean’ windows in the sky,” the report said, published in the journal Astronomy and Astrophysics.

The Planck study calls into question whether the Bicep team measured a cosmological signal belonging to gravitational Big Bang ripples or whether the signal belonged to interstellar dust. But the Paris scientists were quick to explain that their study did not disprove the theory- it only called the methods of observation into question.

The Bicep and Planck teams have agreed to collaborate on a detailed study of each group’s results. Planck team member Richard Bond, an astronomy researcher at the University of Toronto, believes that collaboration would be extremely helpful. “Planck showed that dust could possibly be the entire Bicep2 signal, but Planck alone cannot decide. We have to do this in combination with Bicep2.”

The puzzle of the early universe has long plagued scientists. The predominantly accepted theory of the Big Bang states that the universe began with sudden and rapid anti-gravitational inflation. Astronomers believe that this explosion would have produced gravitational waves that rippled outwards. But the scientific community isn’t sure that the Bicep team found these waves at all.