In recent weeks the astrophysics community has been buzzing following the discovery that the universe appears to be filled with a background hum of gravitational waves. Using radio telescopes in the Africa, Asia, Australia, Europe and the US, several teams have noted the same thing: that gravitational waves leave a faint fingerprint in the signals received from pulsars within our galaxy. The discovery is another exciting breakthrough within multimessenger astronomy.

In this episode of the Physics World Stories podcast, Andrew Glester explores the implications of the new gravitational wave discovery, announced on June 28 by the NANOGrav collaboration in the US. He is joined by Cherry Ng, an astronomer at the Laboratory of the Physics and Chemistry of the Environment and Space, part of the French National Centre for Scientific Research (CNRS). In the podcast, you will hear about what this gravitational wave signals can reveal about the massive objects triggering them, most likely the merger of supermassive black holes.