@sonhouse saidHow do you know that?
@Metal-Brain
There are galaxies with no dark matter and Mond will not explain that.
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@metal-brain saidDarling, these days even your Magic Pixie Dream Girl Hossenfelder has rejected MOND in all its various fantabulations. Let go of your obsession, with both of them.
@sonhouse
So does that mean you reject Modified Newtonian Dynamics? Yes or no?
@shallow-blue saidThe problem with dark matter (aside that there is no evidence it exists) is that it does not explain the rotation curve of galaxies. Go ahead and theorize any amount of dark matter you want, it will not explain why the outermost stars in the galaxy go so much faster than those nearer to the center of the galaxy. And I already saw that video from Hossenfelder. She does NOT really reject MoND. She said more research has to be done to know for sure.
Darling, these days even your Magic Pixie Dream Girl Hossenfelder has rejected MOND in all its various fantabulations. Let go of your obsession, with both of them.
Look into Hossenfelder's previous videos supporting the idea of MoND before that latest one. You will get a better idea of how her opinion has evolved. There are serious problems with dark matter that you are not looking at. Galaxy rotation curves do now seem to obey the existing laws of gravity.
Measuring the speed of stars is not an easy thing to do. It may be that astronomers got their measurements wrong. That would best satisfy Occams razor.
@Metal-Brain
There is POSITIVE evidence dark matter exists and further, there are galaxies that have not much which changes the dynamics of how they revolve around a common center.
https://www.pnas.org/doi/10.1073/pnas.1516944112#:~:text=The%20evidence%20for%20the%20existence,in%20the%20universe%2C%20gravitational%20lensing%2C
I guess the work of actual astronomers doesn't cut it with you since you know SO much more and have such massively intelligent fringe sites to go to rather than real scientists.
@sonhouse
"There is POSITIVE evidence dark matter exists"
No, there is a hypothesis that dark matter exists with no evidence.
https://ui.adsabs.harvard.edu/abs/1984ApJ...286....7B/abstract
@Metal-Brain
Both theoretical and astronomical evidence. Without dark matter galaxies would be very different, probably a lot smaller because of lack of mass producing enough gravitational attraction to get large galaxies formed. And they know the mass is there because of gravitational lensing showing the presence of large masses much more than the obvious measurable masses of regular matter and stars.
The fact you choose not to believe it has no bearing on reality.
You are free to choose whatever fringe site you want but that doesn't mean we listen or give a rats ass what you think.
@sonhouse saidYou have not explained the rotation curves of galaxies. Dark matter cannot explain that in any abundance. The inner stars in a galaxy are supposed to do a full rotation around the center much faster than the outer stars. They don't.
@Metal-Brain
Both theoretical and astronomical evidence. Without dark matter galaxies would be very different, probably a lot smaller because of lack of mass producing enough gravitational attraction to get large galaxies formed. And they know the mass is there because of gravitational lensing showing the presence of large masses much more than the obvious measurable masses ...[text shortened]... ose whatever fringe site you want but that doesn't mean we listen or give a rats ass what you think.
The year of Mercury is how much shorter than the year of Neptune?
How does that compare to the inner stars in a galaxy and the outer stars of a galaxy?
Is the ratio comparison consistent with our laws of gravity as we know them? NO!
How can dark matter possibly explain that? And why do you have to make up a purely theoretical non baryonic matter instead of regular matter you simply cannot see? Why are you assuming you would see all regular matter? It is not easy to see black holes. Why did you rule out underestimating how many black holes there are in galaxies? Why did you rule out gas and dust you cannot see in galaxies? Why did you rule out more of these that have not come close enough to see?
https://www.reuters.com/article/us-space-oumuamua-idUSKCN1TW3RP/
And these?
https://en.wikipedia.org/wiki/Rogue_planet
Just because you cannot see regular matter does not mean it is not there.
Is Planet X non baryonic matter? There is theoretical and astronomical evidence of Planet X too. Why can't you see it?
@Metal-Brain
You keep harping on MOND and there are updates to that hypothesis but it still has big problems, one being it cannot explain gravitational lensing which is why we can figure out where the stuff is. MOND ONLY tries to explain the speed of stars around the fringe of a galaxy and cannot fit it into gravitational lensing.
@sonhouse saidWhat does gravitational lensing have to do with it? What "stuff" are you talking about? I have no idea what you are talking about. Gravitational lensing is how you detect black holes.
@Metal-Brain
You keep harping on MOND and there are updates to that hypothesis but it still has big problems, one being it cannot explain gravitational lensing which is why we can figure out where the stuff is. MOND ONLY tries to explain the speed of stars around the fringe of a galaxy and cannot fit it into gravitational lensing.
Do you acknowledge there are more black holes than people used to think there were or not? There is your extra matter and it is dark, but it is normal baryonic matter. There you go. I told you that a long time ago and you insisted all the black holes were accounted for because of gravitational lensing and you were wrong. Gravitational lensing is not magic. It cannot scan the universe for you. It is only a tool that requires you to do the work. If you are not searching hard enough you are not going to find all of the black holes.
I didn't used to know how many bats were flying around at night either until I sat on the porch when it was getting dark one night. I thought they were birds until I realized birds don't fly when it gets that dark. If you want to know how many things are in the sky that are hard to see you have to make an effort to find them all.
@Metal-Brain
Figure it out for yourself. You don't want to learn stuff you just want to tear up anyone else saying anything about science. I don't have time for your bullshyte.
@sonhouse saidJust admit you don't know.
@Metal-Brain
Figure it out for yourself. You don't want to learn stuff you just want to tear up anyone else saying anything about science. I don't have time for your bullshyte.