From Space Daily:
A team of researchers from Case Western Reserve University has found that gravitational radiation-widely expected to provide “smoking gun” proof for a theory of the early universe known as “inflation”-can be produced by another mechanism. According to physics scholars, inflation theory proposes that the universe underwent a period of exponential expansion right after the big bang.
A key prediction of inflation theory is the presence of a particular spectrum of “gravitational radiation”-ripples in the fabric of space-time that are notoriously difficult to detect but believed to exist nonetheless.
“If we see a primordial gravitational wave background, we can no longer say for sure it is due to inflation,” said Lawrence Krauss, the Ambrose Swasey Professor of Physics and Astronomy at Case Western Reserve.
At the same time the researchers find that gravitational waves are a far more sensitive probe of new physics near the highest energy scale of interest to particle physicists than previously envisaged. Thus their work provides strong motivation for the ongoing quest to detect primordial gravitational radiation.
More here. [Thanks to Pete Chapman.]