What Is This? The Mystery of the Runaway Black Hole

Script written by Nathan Clarke In 2023, astronomer Pieter van Dokkum was reviewing archival Hubble images when he noticed something that had no explanation: a perfectly straight line of light stretching 200,000 light-years out of a distant galaxy. Twice the diameter of the Milky Way. A streak across the universe. It wasn't an error. It was real. And for two years, nobody could fully explain what it was. Until the James Webb Space Telescope pointed at it in 2025 and confirmed something nobody had ever seen before: a supermassive black hole of 10 to 20 million solar masses, ejected from its galaxy, racing through intergalactic space at 954 kilometres per second — fast enough to cover the Earth-Moon distance in 14 minutes — leaving behind a 200,000 light-year trail of newborn stars. Its name is RBH-1. The first confirmed runaway black hole in history. Subscribe for weekly space documentaries. Sources: NASA/ESA Hubble — Runaway Black Hole Discovery: https://science.nasa.gov/missions/hubble/hubble-sees-possible-runaway-black-hole-creating-a-trail-of-stars/ van Dokkum et al. 2023 — Original Paper ApJL: https://iopscience.iop.org/article/10.3847/2041-8213/acc2bb van Dokkum et al. 2025 — JWST Confirmation ApJL: https://iopscience.iop.org/article/10.3847/2041-8213/ae3d0e NASA — James Webb Space Telescope: https://science.nasa.gov/mission/webb/