In 2014, Scientists found a strong evidence of primordial gravitational waves. The waves were thought to be produced a few seconds after the Big Bang. The theory, dubbed as BICEP2, was printed in Journal Physical Review Letters.
On Friday, European Space Agency posted a summary and acknowledged that BICEP2 was an incorrect discovery. Next day, the intergovernmental organization issued a press release which verifies that the discovery was result of an optical illusion.