APOD: Globular Cluster M15 from Hubble (2011 May 03)

[Harry SevenEagles]

Fantastical !

[Ailean4321]

Dear Chris & Cabellasus,
What are your occupations? I'm curious. & Intrigued.

[Ailean4321]

Fantastical !

prettttyyyy

[Chris Peterson]

Dear Chris & Cabellasus,
What are your occupations? I'm curious. & Intrigued.

I'm an astrophysicist, currently working in the area of meteor analysis. As an astronomer, I live on the border between amateur and professional astronomy, as my interests and work overlap both.

[Ailean4321]

Amazing, you have fulfilled two of my future aspirations:
Astronomer/physicist & Colorado.
Although, I don't know that my brain is cut out for the former.

[Ailean4321]

For the visually-oriented among us, some fun links. I couldn't find any done really, really well in HD though... Sounds like it could be a fun simulation project for someone.
-Noel

Very much appreciate the videos.

[Ann]

BMAONE and Noel, thanks for your links!

Ann

[Guest]

Should be called "Queen Anne's Lace" cluster.

Meteormaid@gmail.com

[geckzilla]

Amazing, you have fulfilled two of my future aspirations:
Astronomer/physicist & Colorado.
Although, I don't know that my brain is cut out for the former.

Sure it is, just start watching the astronomy 101 videos. Then amaze and baffle your friends with your new found knowledge!

[garry]

If other forms of galaxy structures all have a black hole, rotate & are effected by gravity, and a globular galaxy is supposed to have a black hole, does not rotate and is effected by gravity, why the difference? Are the stars moving in towards the centre or moving away? One can speculate as to why, but it would be nice for someone to say sometime we don't now!

[Chris Peterson]

If other forms of galaxy structures all have a black hole, rotate & are effected by gravity, and a globular galaxy is supposed to have a black hole, does not rotate and is effected by gravity, why the difference? Are the stars moving in towards the centre or moving away? One can speculate as to why, but it would be nice for someone to say sometime we don't now!

Not all galaxies have central black holes, and not all globular clusters have central black holes. In those that do, the black holes generally have very little gravitational impact on the whole structure. In fact, galaxies and globular clusters behave very similarly. Neither rotate, but both contain large numbers of stars which orbit the center of mass. When galaxies are disc-like, they appear to rotate, because many of their member stars have their angular momentum vectors pointing in a similar direction. But even in flat spirals, the majority of stars are usually found in central bulges that approach being spherical, and those stars orbit at nearly random inclinations. And the overall motion of stars is probably very similar in globular clusters and elliptical galaxies. In them, there is little net movement of stars inwards or outwards. Stars are in orbits of various inclinations and eccentricities, and are individually subject to extensive perturbations due to close encounters with other stars.