In this episode of the Physics World Weekly podcast, we meet Shep Doeleman, who is the founding director of the Event Horizon Telescope. He explains how he and his colleagues obtained that iconic image of the “shadow” of the supermassive at the centre of the Milky Way. Based in the US at the Harvard & Smithsonian Center for Astrophysics, Doeleman explains what the image tells us about the physics of black holes, and he looks forward to the day when we can watch “movies” of dancing black-hole shadows.

Also in this week’s podcast is the geophysicist Sarah Albert, who studies sound propagation in the atmosphere by listening in on rocket launches using high-altitude balloons. Albert works at Sandia National Laboratories in the US and talks about what her research reveals about an atmospheric phenomenon called the “acoustic duct”.