Scientists thought they found evidence of the process behind the expansion of our universe and the Big Bang. They very well may have-- but they're no longer sure about it.
In March, a group of astrophysicists announced that it detected what seemed to be gravitational waves left over from the Big Bang. If correct, the evidence would back up Einstein's theory of relativity and would confirm the theory of cosmic inflation.
The idea behind cosmic inflation is one of most important details of the Big Bang. The theory states that the universe underwent rapid expansion only 10^-35 seconds after the explosion, and allowed the universe to become flat, continuous, and seemingly more uniform. This phenomenon, if it did occur, would have produced fluctuations in the cosmic microwave background (CMB), or photons that were emitted as a bi-product of the Big Bang and are still spreading through the universe today.
In March, astrophysicists from Caltech, UCSD, Harvard, Stanford, and others (the BICEP2 collaboration) used the BICEP2 telescope in the South Pole to identify what they believe to be such fluctuations in the CMB, or B-mode polarization. It was a big deal at the time because it gave concrete evidence of cosmic inflation, previously only a theory. Their results, published this week in the journal Physical Review Letters, now claim some uncertainty about the findings. It turns out that cosmic dust may have gotten in their way.
The team used images of the CMB taken by the Planck satellite, an orbiting satellite run by the European Space Agency (ESA). According to many physicists, the team underestimated the disturbance of cosmic dust in the images and overestimated the amount of B-mode polarization.
The team's method of calibration of the BICEP2 telescope had ruled out the effects of cosmic dust, causing arguments among astronomers and physicists all over. Now the Planck telescope is obtaining data pertaining to the CMB that should more accurately depict the amount cosmic dust in the area the BICEP2 studies.
The scientists extracted explanations of their calibration techniques from the paper, since they failed to account for the dust problem, and are humbly deferring to further scientific analysis before making any more claims.
The paper included a footnote saying that "[w]hile these papers do not offer definitive information on the level of dust contamination in our field, they do suggest that it may well be higher than any of the models considered."
The diminished confidence is obvious, and the team is not taking the uncertainty lightly, but they are taking it with grace. Science is, if anything, the persistently hopeful chasing of a truth that often seems impossible to find.
