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Could Modified Gravity Kill Planet Nine?

nautil.us

11–20 of 157 posts

Re: Could Modified Gravity Kill Planet Nine?

#11
post #2

Fascinating. So this MOND theory works in this case. If I understand correctly, scientists still prefer the dark matter theory because it applies in more cases at galactic scale, and this is just one occurrence of the MOND theory working fine?

They prefer it because it fits the data best.

The biggest piece of evidence for DM is the BAO patterns in the CMB. Forget all the other numerous mountains of evidence, that is the biggest one. MOND has no good explanation for this without introducing something that's effectively DM.

Re: Could Modified Gravity Kill Planet Nine?

#12

Pluto is a planet ( /s but not really)

Pluto should have had some grand-father clause. Keep it a planet for historical sake, but with an asterisk. So we wouldn't keep arguing about the new objects that are same size or bigger, yes, Pluto isn't a planet. But lets just go ahead and acknowledge that we are going to call Pluto a planet in 'name-only' for the memories.

Re: Could Modified Gravity Kill Planet Nine?

#13
post #6
post #2

Fascinating. So this MOND theory works in this case. If I understand correctly, scientists still prefer the dark matter theory because it applies in more cases at galactic scale, and this is just one occurrence of the MOND theory working fine?

I think dark matter is more appealing to them because the first person to discover a dark matter object is going to get something named after them.

That doesn't make any sense at all unless they simultaneously believe that DM is actually the right answer.

Re: Could Modified Gravity Kill Planet Nine?

#15
post #2

Fascinating. So this MOND theory works in this case. If I understand correctly, scientists still prefer the dark matter theory because it applies in more cases at galactic scale, and this is just one occurrence of the MOND theory working fine?

We have found galaxies with differing amounts of dark matter (as measurer by rotational speed) and have confirmed these measurements with gravitational lensing being more or less effective.

Re: Could Modified Gravity Kill Planet Nine?

#16

Dr Becky explaining the MOND theory and why it's invalid --> https://www.youtube.com/watch?v=HlNSvrYygRc

For those of us who don't already know her, can you explain who Dr Becky is and why we should trust her perspective? I can't watch it just yet, but judging from the thumbnail this feels like just another educational YouTube video, and while I watch more than my fair share of that genre I don't tend to implicitly trust it on complicated scientific topics.

Re: Could Modified Gravity Kill Planet Nine?

#17

Dr Becky explaining the MOND theory and why it's invalid --> https://www.youtube.com/watch?v=HlNSvrYygRc

For those of us who don't already know her, can you explain who Dr Becky is and why we should trust her perspective? I can't watch it just yet, but judging from the thumbnail this feels like just another educational YouTube video, and while I watch more than my fair share of that genre I don't tend to implicitly trust it on complicated scientific topics.

She has a PhD in astrophysics and is a specialist on blackholes. In her video's such as this one she goes into what the paper claims and then looks at the evidence for and against, based on other research and theory.

She knows her stuff and approaches things rationally.

Re: Could Modified Gravity Kill Planet Nine?

#18

Dr Becky explaining the MOND theory and why it's invalid --> https://www.youtube.com/watch?v=HlNSvrYygRc

For those of us who don't already know her, can you explain who Dr Becky is and why we should trust her perspective? I can't watch it just yet, but judging from the thumbnail this feels like just another educational YouTube video, and while I watch more than my fair share of that genre I don't tend to implicitly trust it on complicated scientific topics.

Wikipedia: `Rebecca Smethurst, also known as Dr. Becky, is a British astrophysicist, author, and YouTuber who is a junior research fellow at the University of Oxford. She was the recipient of the 2020 Caroline Herschel Prize Lectureship, awarded by the Royal Astronomical Society, as well as the 2020 Mary Somerville Medal and Prize, awarded by the Institute of Physics. In 2022, she won the Royal Astronomical Society's Winton Award "for research by a post-doctoral fellow in Astronomy whose career has shown the most promising development".`

Re: Could Modified Gravity Kill Planet Nine?

#19

Dr Becky explaining the MOND theory and why it's invalid --> https://www.youtube.com/watch?v=HlNSvrYygRc

For those of us who don't already know her, can you explain who Dr Becky is and why we should trust her perspective? I can't watch it just yet, but judging from the thumbnail this feels like just another educational YouTube video, and while I watch more than my fair share of that genre I don't tend to implicitly trust it on complicated scientific topics.

She has a PhD in astrophysics, with her academic work centered around the co-evolution of supermassive black holes and their host galaxies. As far as I can tell, she's still an active researcher, even though she clearly spends a lot of her time on her Youtube channel.

Re: Could Modified Gravity Kill Planet Nine?

#20

Dr Becky explaining the MOND theory and why it's invalid --> https://www.youtube.com/watch?v=HlNSvrYygRc

For those of us who don't already know her, can you explain who Dr Becky is and why we should trust her perspective? I can't watch it just yet, but judging from the thumbnail this feels like just another educational YouTube video, and while I watch more than my fair share of that genre I don't tend to implicitly trust it on complicated scientific topics.

The YouTube channel doesn't have hard verification, but claims that "Dr Becky Smethurst, an astrophysicist at the University of Oxford."

and Wikipedia editors seem to agree, with further references https://en.m.wikipedia.org/wiki/Becky_Smethurst

The video cites two papers, one for MOND and one against, so you can look up the papers.

It's better than the OP article, which ignores the counterarguments against MOND.

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