Astronomy Cast Ep. 721: Rogue Planets By Fraser Cain & Dr. Pamela Gay Streamed live on May 20, 2024. Most of the exoplanets we’ve found are around stars, where they belong. But a few have been found free-floating in interstellar space. The evidence is growing that there are a lot of them out there, maybe even more than planets with stars. How do they form and how can we learn more about them?