From Dr. Becky.
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We don’t yet understand the early Universe. And that’s not surprising because for a long time we weren’t able to observe the distant Universe, because telescopes couldn’t see that far. That is until the James Webb Space Telescope, which has now allowed us to see galaxies at greater distances than ever before, and those galaxies are confusing us. Which is not surprising since all our models were extrapolated from what we’d seen with the Hubble Space Telescope in the nearby Universe. So because we’re still learning about the early Universe, there’s been lots of discussion in research articles about what could explain what we’ve seen, with lots of ideas raised. One that’s been highlighted this past month is in a research paper from McGaugh and collaborators which focussed on the “over massive” galaxies that JWST has found, that I’ve covered on this channel before including their discovery, and some possible explanations for them. Now McGaugh and collaborators have another possible explanation that these galaxies were predicted by an alternative theory of gravity, known as MOND, that doesn’t need dark matter to explain the Universe…
My previous videos on JWST’s overmassive galaxies problem – https://www.youtube.com/playlist?list=PLd19WvC9yqUcl4TksvGTTL5NSdQwobWvh
My previous video on the evidence for dark matter – https://www.youtube.com/watch?v=nbE8B7zggUg
My previous videos on alternate theories of gravity – https://www.youtube.com/playlist?list=PLd19WvC9yqUe_IteZI-qP_yqvohNR9Of3
McGaugh et al. (2024) – https://iopscience.iop.org/article/10.3847/1538-4357/ad834d
Milgrom (1983; first MOND paper) – https://articles.adsabs.harvard.edu/pdf/1983ApJ…270..365M
Anglés-Alcázar et al. (2017; FIRE sims) – https://academic.oup.com/mnras/article/470/4/4698/3871367?login=true
Rodriguez-Gomez et al. (2016; Illustris sims) – https://academic.oup.com/mnras/article/458/3/2371/2589235
00:00 Introduction
02:14 AD | Novium Hoverpens
03:57 A recap of JWST’s "overmassive" galaxies problem
09:23 What is MOND?
13:22 What are McGaugh and collaborators claiming?
16:59 What are the caveats and implications for this result?
23:42 Bloopers
Video filmed on a Sony ⍺7 IV
Video edited by Martino Gasparrini: https://www.fiverr.com/mgs_editing
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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.
