I "Centaurus A Contradicts Dark Matter Models"

[megacal]

According to the article in Astronomy Magazine June 2018, the satellite galaxies of Centaurus A are rotating
in the same direction in a relatively thin plane, vs randomly distributed if there is a dark matter halo/sphere
surrounding large galaxies.

Any thoughts on this new finding? I've only had undergrad physics & math, but am very intrigued & curious about dark matter...or if it even exists, since there is only indirect evidence for it.

1. Are we inside a cloud of it?
2. If it has mass, doesn't it coalesce like barions into massive
   solid objects over time?

Thanks in advance for your insights.

 

[phinds]

1. Are we inside a cloud of it?
2. If it has mass, doesn't it coalesce like barions into massive
   solid objects over time?

Have you done any research at all into what dark matter is? The most cursory reading regarding it will answer both questions immediately.

And by the way, the question of "does it exist?" is very much the wrong way to look at it. The point is that SOMETHING exists and we understand its characteristics pretty well, we just don't know what it is so we call it "dark matter" until we have a better understanding of what it IS to go along with our understanding of what it does.

 

[megacal]

Sorry, Phinds, but that's a very condescending reply to what I still believe are reasonable
questions. This is why I hesitate to ask any questions here.

Yes, I've read many articles about dark matter, and searched here first before asking my questions.

My bad, I should know better by now. Sorry to waste your time.
I'll look elsewhere for answers.

 

[PeterDonis]

According to the article in Astronomy Magazine June 2018

Do you mean this article?

http://www.astronomy.com/news/2018/02/centaurus-as-satellites-rotate-together

It's helpful to provide a link when you give a reference, so it's clear exactly what you are referencing.

Also, the arxiv preprint of the actual paper is here:

https://arxiv.org/abs/1802.00081

That is probably a better basis for discussion.

that's a very condescending reply to what I still believe are reasonable
questions

The questions are reasonable. They are also answered easily by looking at the Wikipedia article on dark matter, which does a pretty good job of covering the subject and gives many good references. You will be able to ask more focused questions and get more useful information here if you have some basic background first.

 

[megacal]

Thank you both for your replies.

I'll spend more time researching DM to be better prepared to ask intelligent questions here
in the future.

https://en.wikipedia.org/wiki/Dark_matter
https://home.cern/about/physics/dark-matter
https://www.nature.com/articles/nphys4039
https://www.sciencedaily.com/news/space_time/dark_matter/