After making history by flying by Pluto in 2015, NASA’s New Horizons spacecraft is speeding toward a New Year’s Day 2019 flyby of a mysterious world in the outer realm of the solar system. In this episode of Gravity Assist, Jim Green talks with New Horizons Principal Investigator Alan Stern about what we’ve learned about Kuiper Belt object 2014 MU69 and the remarkable story of how — against all odds — the New Horizons team captured MU69’s fleeting shadow on Earth as the object passed in front of a distant star.

For the full podcast and transcript, visit