The Mystery of Mars' Missing Air

Why is there no air on Mars? NASA's MAVEN mission has supplied some details on how our neighbor lost what was likely a robust atmosphere comparable to Earth's. Spoiler alert: size does matter. Mars' diminutive scale poses a number of problems for holding onto the atmosphere. MAVEN has now witnessed erosion of the atmosphere due to the solar wind. Hear about Mars and more on this episode of Walkabout the Galaxy.