A team of astronomers generated excitement last year when they claimed to have found an evidence for primordial gravitational waves, which are believed to have been produced when the universe underwent a rapid period of growth spurt a fraction of a second after the Big Bang.

The discovery of gravitational waves is crucial to many of the theories regarding the early universe but a press release made by the European Space Agency (ESA) suggests that what had been detected by the BICEP2 team that announced the discovery in March 2014 was in essence an optical illusion.

In the statement released on Friday, Jan. 30, ESA said that a joint analysis of data coming from the Planck satellite, BICEP2 and Keck Array experiments has found that there is no conclusive evidence of these primordial gravitational waves.

Astronomers have been using powerful telescopes such as the Planck and BICEP2 to look for signs of these waves in the cosmic microwave background, or CMB, the left-over radiation that was emitted 380,000 years after the Big Bang that led to the formation of the universe about 14 billion years ago, and which now permeates the cosmos.

Theory holds that the waves would have produced a swirly pattern in the CMB dubbed the B-mode polarization. Such was what astronomers reportedly discovered in March last year.

The European Space agency, however, said that the B-mode polarization in the CMB that the BICEP2 measured was not caused by the presence of these gravitational waves but rather of obscuring space dust.

"The BICEP2 team presented evidence favouring the interpretation that this signal originated in primordial gravitational waves," ESA said in a statement. "However, there is another contender in this game that can produce a similar effect: interstellar dust in our Galaxy, the Milky Way."

The dust in the Milky Way that emits near-infrared light and has the same characteristics as the microwave background appeared to have confused the scientists' observation.

"It turns out that the fraction due to dust had been significantly underestimated," said the French Planck team. "Once the fraction [of the signal] due to galactic [dust] emissions has been correctly subtracted, an excess remains, but at present it is too weak to be considered a detection."

The results though did not seem to come as a surprise because since the supposed discovery of the gravitational waves in 2014, many scientists have already heavily scrutinized the BICEP2 data.