Uploaded April 2026 | Updated September 2026, 2 weeks ago
Above and below our galaxy the Milky Way are two gigantic bubbles blasting out gamma rays, the most energetic light in the Universe. It’s only when we mask out the bright objects and the glow from the gas in the milky way that we notice the emission from the bubbles. And it’s very distinct, the emission has a different signature to the normal diffuse emission from gas in the milky way, a different spread of energies of gamma ray light that they’re emitting. With much higher energy light given off than we typically see from the galactic plane. To do that, we need high-speed electrons accelerated to nearly the speed of light which can collide with a low-energy photon of light, something like infrared or radio light, the collision slows the electron but adds a load of energy to the photon producing gamma rays. This is known as inverse Compton scattering. The other feature of the Fermi bubbles is that the edges are very clear, and sharp, suggesting a a sudden release of energy caused the bubbles rather than a slower process. Not to mention the fact the Fermi bubbles are absolutely huge. This is an image of the entire sky, with the bubbles covering roughly 10% of the entire image. They’re 50,0000 light years long from top to bottom, that’s half the width of the entire Milky way galaxy of stars. So, given everything we know about the bubbles, what are some of the possible explanations for the Fermi bubbles? Watch the full video to find out more...
Pillepich et al. (2021) - arxiv.org/pdf/2105.08062
Yang et al. (2022) - arxiv.org/pdf/2203.02526
Sands et al. (2025) - arxiv.org/pdf/2510.14908
Video filmed on a Sony ⍺7 IV
Video edited by Martino Gasparrini: fiverr.com/mgs_editing
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📚 My book, "A Brief History of Black Holes", out NOW in hardback, paperback, e-book and audiobook (which I narrated myself!): lnk.to/DrBecky
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👕 My merch, including JWST designs, are available here (with worldwide shipping!): dr-becky.teemill.com
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🎧 Royal Astronomical Society Podcast that I co-host: podfollow.com/supermassive
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🔔 Don't forget to subscribe and click the little bell icon to be notified when I post a new video!
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👩🏽💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford (Christ Church). 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.
drbecky.uk.com
Above and below our galaxy the Milky Way are two gigantic bubbles blasting out gamma rays, the most energetic light in the Universe. It’s only when we mask out the bright objects and the glow from the gas in the milky way that we notice the emission from the bubbles. And it’s very distinct, the emission has a different signature to the normal diffuse emission from gas in the milky way, a different spread of energies of gamma ray light that they’re emitting. With much higher energy light given off than we typically see from the galactic plane. To do that, we need high-speed electrons accelerated to nearly the speed of light which can collide with a low-energy photon of light, something like infrared or radio light, the collision slows the electron but adds a load of energy to the photon producing gamma rays. This is known as inverse Compton scattering. The other feature of the Fermi bubbles is that the edges are very clear, and sharp, suggesting a a sudden release of energy caused the bubbles rather than a slower process. Not to mention the fact the Fermi bubbles are absolutely huge. This is an image of the entire sky, with the bubbles covering roughly 10% of the entire image. They’re 50,0000 light years long from top to bottom, that’s half the width of the entire Milky way galaxy of stars. So, given everything we know about the bubbles, what are some of the possible explanations for the Fermi bubbles? Watch the full video to find out more...
Pillepich et al. (2021) - arxiv.org/pdf/2105.08062
Yang et al. (2022) - arxiv.org/pdf/2203.02526
Sands et al. (2025) - arxiv.org/pdf/2510.14908
Video filmed on a Sony ⍺7 IV
Video edited by Martino Gasparrini: fiverr.com/mgs_editing
---
📚 My book, "A Brief History of Black Holes", out NOW in hardback, paperback, e-book and audiobook (which I narrated myself!): lnk.to/DrBecky
---
👕 My merch, including JWST designs, are available here (with worldwide shipping!): 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 (Christ Church). 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.
drbecky.uk.com
