From Dr. Becky.

AD | Go to https://surfshark.com/drbecky and use code DRBECKY at checkout to get 4 extra months of Surfshark VPN | Above and below our galaxy the Milky Way are two gigantic bubbles blasting out gamma rays, the most energetic light in the Universe. For 15 years, we’ve been trying to figure out what created them. We thought we had the answer. And now new research has just complicated everything. These are the Fermi Bubbles found by the Fermi gamma ray telescope back in 2010. Two bubbles of gas so hot they’re giving out gamma ray light a billion times more energetic than light we see with our eyes. And for the past 15 years us astrophysicists have been trying to figure out what these bubbles are and what formed them? And at the start of the 2020s we thought there was finally enough pieces of evidence that had come together to solve the Fermi bubble mystery, but then at the end of 2025, a new research paper was published that has put the cat amongst the pigeons once again…

Pillepich et al. (2021) – https://arxiv.org/pdf/2105.08062
Yang et al. (2022) – https://arxiv.org/pdf/2203.02526
Sands et al. (2025) – https://arxiv.org/pdf/2510.14908

00:00 Introduction
02:48 How did we find the Fermi bubbles and why are they glowing in
gamma rays?
06:15 The possible explanations for the Fermi bubbles
11:46 The evidence in support of each explanation
15:23 Bloopers

Video filmed on a Sony ⍺7 IV
Video edited by Martino Gasparrini: https://www.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!): 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 (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.

http://drbecky.uk.com