Space junk – debris left by humans in space – is a growing danger for satellites and space missions orbiting the Earth. It turns out that the Moon also has space junk and in this episode of the Physics World Weekly podcast, Roberto Furfaro and Vishnu Reddy of the University of Arizona talk about the challenges of tracking lunar space junk and identifying its origins.

Also this week, the teacher David Marshall talks about the sometimes byzantine process of correcting errors in physics textbooks, curricula and exams. He also shares some of the more bizarre mistakes he has found over the years – including one about bouncy light, which has yet to be corrected.

• Marshall has written an article for Physics World about his adventures in error correction: “Error carried forward: why we need to be vigilant even about textbooks”.