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Currently Playing: How do black holes get so SUPERMASSIVE?

AD | Go to https://ground.news/drbecky to stay fully informed with the latest Space and Science news. Save 40% off the Vantage plan through my link for unlimited access | How do black holes get to be SUPERMASSIVE?! We're talking millions to billions of times heavier than the Sun. With all that mountain of matter crushed down until it becomes so dense, that we can’t see it, because not even light can escape. We know black holes form when a star dies, goes supernova, and its core collapses, but that only makes black holes 10 times heavier than the Sun. How do you get something as massive as the SUPERMASSIVE black hole at the centre of the Milky Way that’s 4 million times heavier than the Sun, that could easily fit inside the orbit of Mercury. Or the supermassive black hole at the centre of M87 that’s 6.5 billion times heavier than the Sun, with an event horizon that would engulf the Solar System. For a long time now we’ve thought that the only way this can happen is when two galaxies collide and merge together, increasing the mass of both the galaxy and its supermassive black hole at the same time, explaining the well known correlation we see between the two objects. But a new paper by Jewell and collaborators has shown that mergers aren’t the only way supermassive black holes grow, by studying the black holes in merger-free galaxies, confirming something that’s long been predicted by simulations… Papers mentioned: Jewell et al. (2026) - https://arxiv.org/pdf/2609.22434 Simmons et al. (2012) - https://arxiv.org/pdf/1207.4190 Simmons, Smethurst, Lintott (2017) - https://arxiv.org/pdf/1705.10793 Previous videos: https://youtu.be/Dr8CJAOlGVc?si=W1lHHejIpj-q6z08 https://youtu.be/3DLylJZBBLo?si=Z07RGNynG0jDvXMK 00:00 - Introduction 04:31 - I - How do galaxy mergers grow black holes? 08:45 - II - How do you find merger-free galaxies? 14:44 - III - How do black holes grow to be supermassive without galaxy mergers? 17:38 - Bloopers Video filmed on a Sony ⍺7 IV Video edited by Martino Gasparrini: martino.freelance@gmail.com Video produced by Marina Hui & Dr Becky Smethurst --- 📚 My book, "A Brief History of Black Holes", out NOW in hardback, paperback, e-book and audiobook (which I narrated myself!): http://lnk.to/DrBecky --- 👕 My merch, including JWST designs, are available here (with worldwide shipping!): https://dr-becky.teemill.com/ --- 🎧 Royal Astronomical Society Podcast that I co-host: podfollow.com/supermassive --- 🔔 Don't forget to subscribe and click the little bell icon to be notified when I post a new video! --- 👩🏽‍💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford. I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars. http://drbecky.uk.com