Join host Dr. Franck Marchis and guest Dr. Andy Rivkin (Johns Hopkins University Applied Physics Laboratory) for a discussion on asteroid 2024 YR4 and its potential impact on the Moon. Thanks to new observations with the James Webb Space Telescope (JWST), scientists have refined the asteroid's orbit and determined there is about a 4% chance it could strike the Moon in December 2032. While there is no risk to Earth, a lunar impact could create a crater nearly a kilometer wide and send debris into space—possibly affecting satellites or even producing a visible meteor shower. In this episode, we'll explore how JWST contributed to narrowing the odds, what such an impact would mean for lunar science, and how planetary defense research helps us better understand and prepare for near-Earth objects. NASA Blog: https://science.nasa.gov/blogs/planetary-defense/2025/06/05/nasas-webb-observations-update-asteroid-2024-yr4s-lunar-impact-odds/ (Recorded live 25 September 2025.)