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Globular Clusters part 2

I just posted about Globular clusters(GC), including M10 around the Milky Way, with a link to DeepSky Videos that included an analysis of several GC around a dwarf spherical galaxy in Fornax.
DeepSky Videos also has a video about more of the GC around the Milky Way. In 2018 using Gaia data astronomers plotted motions of the stars in 91 individual GC and found similar patterns among these samples.
This video has too many interesting descriptions to be summarized here.
Among them are: a subset where some of the GC had stars with very little rotational velocity but more radial velocity that alternated direction.
When looking at a GC like M75 it is not apparent some of those stars are alternately approaching and receding.

When I did my last post I did not know that the collection of GC moving around the Milky Way has different patterns of motion among their stars. There is a subset of 8 called sausage globular clusters because of the shape of the plot of their star's motions.

Wikipedia has only a little information under the topic 'Gaia sausage' and it has a link to only the paper's abstract.
I did not read the paper.
Iron to Hydrogen ratio  (metallicity) defines the age of each star. As I learn more of Robitaiile's solar model I wonder about these assumptions.
I get the message of certainty with comments beginning 'we know' but that just makes me suspicious
A plot using the age of the universe in Gly also makes me suspicious about assumptions in that time line.

Watching this later video does not change the observations of my previous post.

The observed approach/recede combination of motion among some stars cannot come from gravity alone.

link

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