An astrophysicist reacts to DOCTOR WHO | The Doctor was wrong about black holes...

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Doctor Who Season 2 Episode 8 The Impossible Planet sees the Doctor and Rose stranded on a planet in orbit around a black hole. The Doctor claims this is “impossible” - but is it? Which bits of this episode are based in science and which are most definitely fiction? Filmed for all you Whovians out there.

Watch all the previous seasons of Doctor Who on BBC iPlayer: https://www.bbc.co.uk/iplayer/episode...

Check out my other “astrophysicist reacts” videos:    • Astrophysicist reacts...  

Padovani et al. (2017; review paper on AGN showing light emitted by accretion disk across wavelength spectrum) - https://arxiv.org/pdf/1707.07134.pdf
Bondi (1957; negative mass in general relativity - behind paywall unfortunately) - https://journals.aps.org/rmp/abstract...
King (2016; how big can black holes grow, equation for self-gravitational radius) - https://arxiv.org/pdf/1511.08502.pdf


00:00 - Introduction
01:01 - How good is the black hole visualisation?
02:09 - You CAN be in orbit around a black hole
03:26 - A geostationary orbit around a black hole?
05:24 - The Innermost Stable Circular Orbit around a black hole (it’s not “impossible” Doctor)
06:49 - The inevitable radiation burns from a growing, glowing black hole
08:20 - “Gravity funnels”, artificial gravity and negative mass
11:48 - Spaghettification and the self-gravitational radius
13:43 - “the blazen scale” lol
13:59 - Tidal Disruption Events and spaghettification
14:47 - WORMHOLES AND BLACK HOLES ARE TWO DIFFERENT THINGS ROSE
15:58 - Outro
17:28 - Brilliant
18:32 - Bloopers

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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.


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https://rebeccasmethurst.co.uk