12286Backlash to Big Bang Discovery Gathers Steam
- May 22, 2014URL to an interesting article from Scientific AmericanSo maybe there was no super inflation in the early moments of the universe?Comments?Chris
Did you ever stop to think, and forget to start again?
The sun sets behind BICEP2 (in the foreground) and the South Pole Telescope (in the background).
Credit: Steffen Richter, Harvard University
On March 17 Paul Steinhardt, a physicist at Princeton University, abandoned a theory he’d been championing for more than a decade. Known as the “ekpyrotic universe” model, it was an alternative to the prevailing theory of inflation, which says the cosmos expanded faster than the speed of light in the first fraction of a fraction of a second of the big bang. If inflation is true, then the process should have released a burst of gravity waves; in Steinhardt’s model, they shouldn’t exist. On that day in March a team of observers announced at a major press conference at the Harvard–Smithsonian Center for Astrophysics that they had indeed detected the waves, thus providing the first clear look at the universe’s earliest moments. The announcement made a huge splash. “Space Ripples Reveal Big Bang’s Smoking Gun,” trumpeted The New York Times front page. “Discovery Bolsters Big Bang Theory,” proclaimed The Wall Street Journal. Dozens of similar headlines appeared, seemingly everywhere. Steinhardt promptly pronounced his theory dead.
But now he’s not so sure. “The situation,” Steinhardt says, “has changed.” Right from the moment results from the BICEP2 microwave telescope at the South Pole were released, many cosmologists had a sense that the discovery rested on shaky ground. “I think it’s fair to say,” argues William Jones, a physicist also at Princeton, “that the claims struck a lot of people, myself included, as far overreaching what the data can support.” Charles Bennett, a physicist and astronomer at Johns Hopkins University who led research on the Wilkinson Microwave Anisotropy Probe (WMAP) satellite, agrees. “Several of the plots in their paper looked odd to me,” he says.
In the ensuing two months, the doubts have only grown stronger, as physicists have attempted, and failed, to reproduce the BICEP2 team’s calculations—admittedly, without the original data, which the team hasn’t yet provided, and without the “systematics” paper, laying out the possible sources of error, which the team has promised but not yet completed. The paper describing the results themselves has not yet been published by a peer-reviewed journal, although that process is underway.
Growing doubts in the astronomical community, meanwhile, have been raised, first in private and over e-mail, then in a blog post by physicist Adam Falkowski, of the French National Center for Scientific Research, in Paris, and most recently by articles in The Washington Post, New Scientist, Science News and other outlets.
If the detection of primordial gravity waves weren’t such an enormous deal in the first place, nobody would be making such a fuss. But the BICEP2 results are crucial to verifying inflation, a cornerstone of modern cosmology. The theory was first proposed back in the early 1980s as a solution to a number of cosmological puzzles. One is the fact that the universe appears the same in all directions even though the opposite sides of the visible cosmos could never, under normal circumstances, have been in contact with one another, even at the very beginning. Another is that the universe appears to be flat—two parallel lines won’t touch even if they traverse the entire cosmos. Inflation explained all of these puzzles by positing an episode of superfast expansion long before the cosmos was a billionth of a billionth of a second old.