Comments on: Dark Galaxy https://briankoberlein.com/2016/09/02/dark-galaxy/ Brian Koberlein Tue, 19 Feb 2019 13:26:59 +0000 hourly 1 https://wordpress.org/?v=5.0.3 By: Tigas https://briankoberlein.com/2016/09/02/dark-galaxy/#comment-4574 Fri, 23 Sep 2016 08:51:26 +0000 https://briankoberlein.com/?p=6241#comment-4574 Hi,

I found this interesting article relevant to this topic:
http://thedaily.case.edu/rotating-galaxies-distribution-normal-matter-precisely-determines-gravitational-acceleration/
Paper on Arxiv:
https://arxiv.org/pdf/1609.05917.pdf
The authors conclusions don’t seem to follow from their findings and are contradicted by a large body of evidence from multiple independent sources but maybe you’re interested in having your take on it?

]]> By: Jean Tate https://briankoberlein.com/2016/09/02/dark-galaxy/#comment-4523 Tue, 06 Sep 2016 20:35:31 +0000 https://briankoberlein.com/?p=6241#comment-4523 “tak[ing] a hard look at the way we perceive the effects of gravity” is something that’s the subject of dozens, nay hundreds, of published papers.

The ideas examined range from the wildest outreaches of theory, to the most prosaic of analyses of observations, and plenty of waystations between. I’m sure that hundreds, if not thousands, of young (and not so young) astronomers and physicists have a secret hope that it’ll be something they do which solves the mystery.

One reason, perhaps, why it’s so hard to come up with good alternatives: the evidence for DM, of the ‘behaves just like Newton/Einstein says’ kind, is so widespread … so many different types of objects, such a huge range of physical scales, very diverse kinds of physics used to estimate “DM here”, observational techniques that boggle the mind, …

So, a great many chalkboards have been worn out already 😉

]]> By: Brian Koberlein https://briankoberlein.com/2016/09/02/dark-galaxy/#comment-4515 Mon, 05 Sep 2016 21:28:01 +0000 https://briankoberlein.com/?p=6241#comment-4515 If most of the mass were concentrated in a black hole at its center, the stellar motions would follow Kepler’s law, like the planets around our Sun. They don’t, and so we know the mass isn’t concentrated in the center.

]]> By: Brian Koberlein https://briankoberlein.com/2016/09/02/dark-galaxy/#comment-4513 Mon, 05 Sep 2016 13:16:15 +0000 https://briankoberlein.com/?p=6241#comment-4513 Dark matter affects light gravitationally, so we can observe its effects.

]]> By: Bruce Elliott https://briankoberlein.com/2016/09/02/dark-galaxy/#comment-4510 Sun, 04 Sep 2016 14:01:48 +0000 https://briankoberlein.com/?p=6241#comment-4510 How do the observations of Dragonfly 44 let us rule out the possibility of an unusually massive black hole at its center? Can we detect or infer the distribution of the unseen mass?

]]> By: Robert Crowley https://briankoberlein.com/2016/09/02/dark-galaxy/#comment-4506 Fri, 02 Sep 2016 16:38:14 +0000 https://briankoberlein.com/?p=6241#comment-4506 With the anticlimactic results from LUX and CDME, while everyone is saying that at least we have a better understanding of what DM isn’t, we actually seem further away from understanding what it is. Our best candidates keep falling by the wayside, and still all we know is that it is the apparent excess of gravity caused by a surplus of, well, nobody honestly has any idea.
So, is there a point in the future, even near future, when we will have to go back to the chalkboard and take a hard look at the way we perceive the effects of gravity?

]]> By: Weam Abou Hamdan https://briankoberlein.com/2016/09/02/dark-galaxy/#comment-4502 Fri, 02 Sep 2016 13:32:30 +0000 https://briankoberlein.com/?p=6241#comment-4502 If Dark Matter cannot be seen, then how can we be sure that Empty Space isn’t Dark Matter?

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