For the first time, the "background hum" of the Universe caused by gravitational waves has been captured. The result is contained in research published in the journals Astronomy and Astrophysics and Astrophysical Journal Letters, as well as on the arXiv platform. The European Pulsar Timing Array (EPTA), of which Italy is a member with the National Institute of Astrophysics, at its Cagliari site, and the University of Milan Bicocca, made a major contribution to the discovery. Specifically, scientists from the eleven European institutions that make up EPTA used data on 15 pulsars, or particularly dense stars that rotate on themselves, which undergo alterations in rhythm due to the passage of gravitational waves of their own. Along with the European organization, Indian and Japanese researchers from the Indian Pulsar Timing Array (InPta), North American NanoGrav, Australian Ppta and Chinese Cpta participated. Special mention comes for Sardinia, whose Sardinia RadioTelescope collected data along with the Effelsberg Radio Telescope in Germany, the Lovell Telescope at the Jodrell Bank Observatory in the United Kingdom, the Nancay Radio Telescope in France and the Westerbork Radio Synthesis Telescope in the Netherlands.