What Juice Revealed About Interstellar Comet 3I/ATLAS

What can a visitor from another star system teach us about our own cosmic neighborhood? Join host Dr. Franck Marchis and guest Dr. Cecilia Tubiana (INAF) for a conversation about interstellar comet 3I/ATLAS and the surprising observations made by ESA's Jupiter Icy Moons Explorer (Juice) during its rare close encounter with this ancient traveler. In November 2025, Juice turned five of its instruments toward 3I/ATLAS, capturing a once-in-a-lifetime dataset as the comet passed through the Solar System. From massive water vapor outgassing to tails stretching millions of kilometers into space, the observations are helping scientists better understand what this object is made of, how it behaves near the Sun, and what it can tell us about planetary systems beyond our own. We'll talk about: • how Juice managed to observe 3I/ATLAS while en route to Jupiter • what scientists learned about the comet's water, dust, and composition • why this interstellar object looks surprisingly familiar—and why that's exciting • how these observations support planetary defense and future spacecraft science • what 3I/ATLAS may reveal about the early history of the Milky Way Press release: https://www.esa.int/Science_Exploration/Space_Science/Juice/Five_things_Juice_has_revealed_about_Comet_3I_ATLAS