In 1964, physicists Robert W. Wilson and Arno A. Penzias heard excess noise from their radio telescopes and thought they’d made a mistake. Was the noise from a previous nuclear bomb test over the Pacific? Was it coming from nearby New York City? Image © NASM/SI, Loan from Robert Wilson
Image above: A pigeon trap used by Nobel Prize winners Penzias and Wilson to remove the two pigeons, roosting in the radio antenna’s large horn. From the Air and Space Museum
Then they suspected two pigeons that were living inside the antenna. It was only after trapping the birds and cleaning the antenna that they were able to conclude that it was cosmic radiation they were hearing, an echo of the universe moments after the Big Bang. So it was thanks in part to those two pigeons that Wilson and Penzias were awarded the Nobel Prize in Physics in 1978 and the Big Bang Theory was confirmed.
Read more at Smithsonian.com.