The signal of Big Bang ripples announced in March this year was too weak to be significant, two separate analyses say, suggesting the astronomers had jumped the gun.
Astronomers this spring announced that they had evidence of primordial gravitational waves - ripples in the fabric of space-time generated in the early Universe.
According to a new study, the scientists did not take into proper account a confounding effect of galactic dust.
"The faint twisting pattern in the polarisation of the cosmic microwave background (CMB), the Big Bang's afterglow, could be accounted for dust in the Milky Way galaxy and not because of primordial gravitational waves as some astronomers claimed earlier this year," explained Uros Seljak, an astrophysicist at University of California, Berkeley.
"Based on what we know right now, we have no evidence for or against gravitational waves," Seljak added.
The announcement in March caused a sensation because it seemed to confirm the theory of cosmic inflation.
This theory holds that the cosmos mushroomed in size during the first fraction of a second after the Big Bang.
Researchers who claimed the evidence for gravitational waves in March used a South Pole-based radio telescope called BICEP.
"They had probably underestimated the fraction of polarisation due to dust in the map which was compiled from data gathered between 2009 and 2013 by the European Space Agency's Planck spacecraft," said authors of the new study reported by the journal Nature.
"There is no evidence for the detection of gravitational waves," said David Spergel from Princeton University in New Jersey.
"But a final determination cannot be made until a more precise dust map, expected to be released by the Planck team in October, is available," he added.
