Astronomy Picture of the Day -- Messier 9 Close-up

NASA ^ | March 23, 2012 | (see photo credit)

[SunkenCiv]

Explanation: Renown 18th century astronomer Charles Messier described this 9th entry in his famous astronomical catalog as "Nebula, without star, in the right leg of Ophiuchus ...". But Messier 9 (M9) does have stars, known to modern astronomers as a globular cluster of over 300,000 stars within a diameter of about 90 light-years. It lies some 25,000 light-years distant, near the central bulge of our Milky Way galaxy. This Hubble Space Telescope close-up resolves the dense swarm of stars across the cluster's central 25 light-years. At least twice the age of the Sun and deficient in heavy elements, the cluster stars have colors corresponding to their temperatures, redder stars are cooler, bluer stars are hotter. Many of the cluster's cool red giant stars show a yellowish tint in the sharp Hubble view.

[SunkenCiv]

[Credit: ESA/Hubble, NASA]

[SunkenCiv]

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[henkster]

I just don’t get how globular clusters exist without some sort of identifiable orbital pattern.

[montanajoe]

This brings back great memories of youth(?) pointing my little 3 inch refractor at M-9 almost nightly

[SunkenCiv]

Nowadays, youth is anything more than ten years ago. :’)

[Talisker]

I just don’t get how globular clusters exist without some sort of identifiable orbital pattern.

One theory I read is that they are the cores of very old galaxies which lost all of their angular momentum through the shedding of vast amounts of mass through lost galactic arms that were full of stars. As a result, the core that is left has been slowed to a standstill, and then unflattens because of lack of spin and opens up into a ball and actually gives birth to new stars through the resulting gravitational compression of interstellar gas.

The theory went on, but by that point I'd run out of beer : )

[martin_fierro]

Messier than what?

[JoeProBono]

[Joe Brower]

"The stars, like dust..."

[blueunicorn6]

“Deficient in heavy elements” - here comes another government program.

[henkster]

Thanks. I still don’t get it. And while I don’t think the beer will help, I don’t see how it could hurt, either.

[SunkenCiv]

And messier than what? That’s never explained.

[GATOR NAVY]

I wonder what the night sky looks like on a planet in the middle of that? Would there even be a real night in that density of stars?

[hattend]

“My God! It’s full of stars!”

[SunkenCiv]

Isaac Asimov’s ‘Nightfall’
http://doctord.dyndns.org:8000/Stories/Nightfall.htm