Uploaded August 2026 | Updated September 2026, 2 weeks ago
Do you lie awake at night mentally spiralling about the inevitable heath death of the Universe?
Well do I have some good news for your sleep score, because there’s some new research that suggests that’s probably not how the Universe ends!
Crucially, the future depends on the knife point balance between how much stuff there is in the universe all attracted together by gravity, vs how much energy is being put into the expansion of the Universe pushing everything apart.
The goldilocks “just so” scenario is when the two balance each other perfectly, so much that the expansion eventually slows and the Universe reaches a certain size until it's in equilibrium, perfect balance.
Or, if there’s less stuff than the critical density, gravity will lose against the expansion, and the Universe expands forever to infinity until all the energy and stuff in the universe is so spread out over such a large area that the average energy or temperature of the Universe plummets and approaches absolute zero in what’s known as The Big Freeze.
But if there’s more stuff than the critical density, gravity will eventually win the tug of war against the expansion, and it will be like watching the big bang but in reverse, with everything reeled back down do the hot dense state we started with, what’s been dubbed The Big Crunch.
Back in April 2024 we got the first data release from DESI, with the first small chunk of the 3D map it made from its first few years of observations, and it was here we got our first hints that the acceleration rate of the expansion of the universe might not be constant.
On this cutting edge of astrophysics research, it doesn't look like 'The Big Freeze' is the most likely option for how the Universe will end anymore. The heat death of the universe might not be so inevitable.
Video filmed on a Sony ⍺7 IV
Video edited by Martino Gasparrini: martino.freelance@gmail.com
Video produced by Marina Hui & Dr Becky Smethurst
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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
---
🔔 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.
drbecky.uk.com
Do you lie awake at night mentally spiralling about the inevitable heath death of the Universe?
Well do I have some good news for your sleep score, because there’s some new research that suggests that’s probably not how the Universe ends!
Crucially, the future depends on the knife point balance between how much stuff there is in the universe all attracted together by gravity, vs how much energy is being put into the expansion of the Universe pushing everything apart.
The goldilocks “just so” scenario is when the two balance each other perfectly, so much that the expansion eventually slows and the Universe reaches a certain size until it's in equilibrium, perfect balance.
Or, if there’s less stuff than the critical density, gravity will lose against the expansion, and the Universe expands forever to infinity until all the energy and stuff in the universe is so spread out over such a large area that the average energy or temperature of the Universe plummets and approaches absolute zero in what’s known as The Big Freeze.
But if there’s more stuff than the critical density, gravity will eventually win the tug of war against the expansion, and it will be like watching the big bang but in reverse, with everything reeled back down do the hot dense state we started with, what’s been dubbed The Big Crunch.
Back in April 2024 we got the first data release from DESI, with the first small chunk of the 3D map it made from its first few years of observations, and it was here we got our first hints that the acceleration rate of the expansion of the universe might not be constant.
On this cutting edge of astrophysics research, it doesn't look like 'The Big Freeze' is the most likely option for how the Universe will end anymore. The heat death of the universe might not be so inevitable.
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!): 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. 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
