HUGE blow for alternate theory of gravity MOND

00:00 - Introduction
01:39 - Curiosity Stream - AD
03:08 - What is MOND?
05:56 - What is the wide binary test?
08:31 - What have previous studies found?
09:34 - How have Banik et al. ruled out MOND?
14:00 - Why Banik et al. think the viral Chae results are unreliable
15:10 - Why this isn't evidence for dark matter
16:24 - Outro & thank you
17:13 - Bloopers

Video filmed on a Sony ⍺7 IV

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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.

[Dr_Kenneth_Noisewater]

Credit to good science here. A proponent of a theory who, when new data (and methods in this case) became available, used that data to rigorously test that theory - and then finds the complete polar opposite - is science approaching its ideals and nice to see. Big credit also to the GAIA mission for collecting these observations!

[annmoore]

I am so impressed by the rigor of a scientist who did not hesitate to show where his earlier paper missed the mark. Just as a lay person, I really respect a scientist who can say, "we were wrong about that explanation." And can then go on to say "we still haven't ruled out using these other approaches." That's a really open mind. Yay, Banik, and yay, Dr. Becky!

[Rubrickety]

The “dueling sigmas” aspect is a nice reminder that these sigma values _aren’t_ measuring the certainty of a given theory being right, but merely of a certain result being due to chance given the data used and assumptions made. Our certainty that the entire Gaia dataset wasn’t replaced wholesale by alien hackers is surely way below even 10-sigma.

[robbierobinson]

Great follow-up on the first video on MOND; thanks for getting it out so quickly after the paper came out. So good to see the scientific method being so clearly shown in operation using the same data set but applying greater rigour to the body of data used.

[Jonno]

This was a very in-depth and well explained video that really helps us understand the gravity of the situation in the field.

[davehall]

Wow! Dr Becky...your explanative clarity of this complex material is wonderful!..you really do bring an appreciation of the science papers to even a lay science curious individual like me!

[muddydave]

Things I love.
1) the way you can summarize the work so far, explain key differences and the consequent outcomes.
2) Fights between scientists. They bring all the data and destroy papers so completely. I wait to see Chae's response.
3)un-cen-turtle-tees.

[davidbignault]

Thank you so much for this video. Your talent in communicating such a complex subject is the envy of us all.

[sailorgeer]

Statistics was probably my least favourite subject in uni, narrowly edging out the dreaded “partial differential equations” for that dubious honour. I’m so glad that there are smart people in the world (like Dr Becky and the other authors mentioned in this vid) who can not only understand the math, but actually apply it to solve the great mysteries of our age :)

[.]

This video should've been posted on MONDay.

[peters]

Thanks for a great video. I'm starting to become skeptical that Bayesian statistics is being applied correctly in the majority of these papers. Between these two papers something is wrong, because the statistics should account for possible error in the data. Getting that level of confidence for either paper seems fishy.

[lambeausouth]

Dr. Becky, I feel lucky to be able to learn from your scientifically trained assessments! Up until now I had not heard of Bayesian Statistics! Your unique viewpoint in itself helps me to understand more than I would have otherwise bend able to ascertain on my own!

[martinedwards]

Beyond the result of dismissing MOND, I’m really impressed with the methodology and rigour of the analysis. This is science at its best.

But, I’m with you. I’d rather be lying on a beach at night, sipping a margarita, and staring up at the stars. Especially with a 40 inch telescope available when I feel like getting up and getting “serious”.

[tonymurphy]

It was already pretty dead with its failure to deal with baryon acoustic oscillations in the CMBR, to be fair. MOND has always been fringe with a strong taste of crank.

[FredPlanatia]

Hi @DrBecky ! Aren't they making a prior assumption on the distribution of eccentricities? Do they have a way of supporting their chosen distribution which was then used to model data from the different gravity models?

[cassert]

I admire Banik's rigorousness for a definitive scientific conclusion, unlike many researchers who throw their research (worse yet, with statistical sugar and hope that people buy it). I need to look back on "my" research mentality, too. On the other thought, I always wondered who was genuinely convinced of MOND except for a few astrophysicists studying it.

[leo]

Muito interessante esta alternativa à Gravidade. Parabéns pela explicação Dr. Beck ❤

[AriFeliZiggy]

I am 9 years old and i love ❤ space and i want to be a astrophysicists when i grow up. i love your videos i also have a question for you, you know how before the big bang their was nothing i don't get how there was nothing no space no nothing it just seems really confusing and i'm hoping you can answer this question bye😊❤🎉😮

[Styphon]

This is what makes science great. The complete willingness to rip each others' (and their own) research and conclusions to shreds.

[stuartrharder]

That first chart with the negative slope is utter nonsense. The slope, is by simple visual analysis, zero or very close to it. Check the relationship with the Theil-Sen Median Slope method. You seem to be searching for oak trees in a pine forest.