Inside a globular cluster

[rockystar]

3 hours ago, SilverAstro said:

A bell is ringing about Population 1 and 2 stars and that the group found in GC are very old, long lived, red, poor in heavy elements having been formed when the universe was young. Another bell is ringing that recently a GC (or some ? GC) confounded  astronomers as found to have some blue young star formation in it (them) ?

Yep, methinks also, some research is called for , , did you find anything since ?

I found a diagram that showed the distribution of the age of stars in a GC and compared it to the HR diagram. It suggested (if I was reading it correctly) that there were a lot of white dwarf stars but it drew a line up towards the giants, through the main sequence. I'll try and lay one over the other when I'm home.

[DRT]

Another question just sprung into my head...

Why are they spherical and not disc-shaped like solar systems and galaxies? Could it be that they do not spin around a central massive gravitational force - i.e. a black hole or a star in those examples - and therefore do not flatten out in a similar way?

[Stu]

Just now, DRT said:

Another question just sprung into my head...

Why are they spherical and not disc-shaped like solar systems and galaxies? Could it be that they do not spin around a central massive gravitational force - i.e. a black hole or a star in those examples - and therefore do not flatten out in a similar way?

Great question Derek! I had a similar thought some time ago and asked on here about it. I think the consensus was that they do orbit around a central point, but in all directions not as a flattened disk. I'm not sure whether any research has been done as to whether there are massive stars in the centre, or even small black holes. 

What I don't understand is why they don't pick up an axial spin and end up as flattened mini spiral galaxies, but seem to stay as balls. It seems inconsistent with all other systems from planetary systems, the solar system right up to galaxies.

[LukeSkywatcher]

Ive never thought so long and hard about GC's before reading this thread. So many questions, so few answers. Think i might have to start reading up on them. Ive always just looked at celestial objects and thought "oh that's nice". Maybe it time i started educating myself as to what it is that i am looking at and the science/mechanics behind what i observe.

[Stu]

24 minutes ago, LukeSkywatcher said:

Ive never thought so long and hard about GC's before reading this thread. So many questions, so few answers. Think i might have to start reading up on them. Ive always just looked at celestial objects and thought "oh that's nice". Maybe it time i started educating myself as to what it is that i am looking at and the science/mechanics behind what i observe.

Definitely do that Paul! It adds so much more to the enjoyment if you actually understand what you are looking at.

[DRT]

I'm so glad I started this thread

When I initially thought of it I honestly believed that two or three people would be able to jump in and answer the whole thing simply because I didn't know the knowledge already existed. To find out that it seems to be an unsolved conundrum is very interesting

 

[Peter Drew]

Guess what we'll all now be looking at next clear opportunity!   

[LukeSkywatcher]

10 minutes ago, DRT said:

I'm so glad I started this thread

When I initially thought of it I honestly believed that two or three people would be able to jump in and answer the whole thing simply because I didn't know the knowledge already existed. To find out that it seems to be an unsolved conundrum is very interesting

 

Us primates, by nature are very curious animals. We as a species (particularly the Human of the species) do and will always try to find answers to the world/universe around us. Lesser primates basically work on natural urges and thought: Food,shelter,procreaction. 

[LukeSkywatcher]

5 minutes ago, Peter Drew said:

Guess what we'll all now be looking at next clear opportunity!   

The double cluster in Perseus during the meteor shower.

[LukeSkywatcher]

21 minutes ago, Stu said:

Definitely do that Paul! It adds so much more to the enjoyment if you actually understand what you are looking at.

Not like i dont have the time to do some reading what with the weather and all that.

Ive been buying the Star Wars helmet collection since January from my local big name book store (Easons). Today when i picked up the latest one, the woman behind the counter asked me if i had a loyalty card. I said no. She said i have spent enough money in the store thus far to warrant about 50 quid in loyalty points.

I have to apply for my loyalty card and the day it arrives in the post, i can and will go down and order a book or two on astronomy. If i have a look online for books........they will order them in for me.

I'm only 1/4 the way through the helmet collection (60 in total)..............so thats a lot of books i can get.

[Peco4321]

I watched a documentary last night recorded a while ago - The Universe on H2 about clusters :

 It's one of those documentaries that really plays on the graphics but worth a watch, all about open and globular clusters. 

 

[rockystar]

Here's the diagram I saw: https://en.wikipedia.org/wiki/Globular_cluster#/media/File:M3_color_magnitude_diagram.jpg

Not sure you can compare it to the HR as it is Visual Magnitude and the HR diagram is Absolute Magnitude.

Slight sidetrack, but I was listening to Startalk Radio this morning and Neil deGrasse Tyson said (paraphrased): "In about a trillion years the speed of the expansion of the universe will have surpassed the speed of light, so light will no longer be quick enough to reach us and that will be the end of cosmology - but it's ok, as we'll have been engulfed by the sun in 4-5 billion years." Nothing GC related, just thought it was interesting.

[SilverAstro]

1 hour ago, LukeSkywatcher said:

Lesser primates basically work on natural urges and thought: Food,shelter,procreaction. 

It's kept me busy.

[DRT]

8 minutes ago, rockystar said:

Here's the diagram I saw: https://en.wikipedia.org/wiki/Globular_cluster#/media/File:M3_color_magnitude_diagram.jpg

Not sure you can compare it to the HR as it is Visual Magnitude and the HR diagram is Absolute Magnitude.

Slight sidetrack, but I was listening to Startalk Radio this morning and Neil deGrasse Tyson said (paraphrased): "In about a trillion years the speed of the expansion of the universe will have surpassed the speed of light, so light will no longer be quick enough to reach us and that will be the end of cosmology - but it's ok, as we'll have been engulfed by the sun in 4-5 billion years." Nothing GC related, just thought it was interesting.

When that happens, no doubt it would be cloudy and we would have missed it anyway

 

[DRT]

47 minutes ago, Peco4321 said:

I watched a documentary last night recorded a while ago - The Universe on H2 about clusters :

 It's one of those documentaries that really plays on the graphics but worth a watch, all about open and globular clusters. 

 

Thanks, Peter, I will watch that soon

 

[Paz]

This is an interesting question. I've had a rummage through "The Complex Lives of Star Clusters" by David Stevenson which has something to say about it. It's a fine book I would recommend but here's some bits of what it says (figures taking the Harris and Webb example about Tucanae 47 referred to below)...

There would likely be perpetual dusk - equivalent to night time on a suburban street - good enough to read a paper but not good enough to drive without headlights (how would they know this?!!!).

There might be 130,000 naked eye stars, maybe 10,000 first magnitude stars (300x more than we've got), maybe 1,000 of these brighter than Sirius is to us (Mag -2), a handful of stars up to mag -9 (100x brighter than Venus - these would remain visible in daylight!).

The book references a couple of pieces of work on this...

Bob King (I think form Sky and Telescope) wrote this, using M4 as the example...

https://astrobob.areavoices.com/2012/04/10/what-the-sky-might-look-like-from-inside-a-globular-cluster/

Harris and Webb from MacMaster University wrote this using Tucanae 47 as the example...

http://io9.gizmodo.com/what-the-night-sky-would-look-like-from-inside-a-globul-1589324556

I guess there would be no amateur DSO observing to be had! I guess the locals would take longer to clock the existence of things in space outside their cluster until they could observe outside of the visual spectrum.

[Ajhayter]

It might not be real, and I'm not sure how accurate it is, but it sure is pretty  Need to take a trip out of the civilisation bubble myself some time, see things up close...

https://www.youtube.com/watch?v=i9XkTiSNy-c

[MattJenko]

On 8/10/2016 at 14:54, SilverAstro said:

A bell is ringing about Population 1 and 2 stars and that the group found in GC are very old, long lived, red, poor in heavy elements having been formed when the universe was young. Another bell is ringing that recently a GC (or some ? GC) confounded  astronomers as found to have some blue young star formation in it (them) ?

Yep, methinks also, some research is called for , , did you find anything since ?

I think the blue stars are thought to be a result of star collisions, so 2 older stars combine to create a bigger new star which then burns brighter as it is larger. The Blue Stragglers.

[Stub Mandrel]

I bet astronomy would be limited by the extra natural LP, until they got space telescopes when they would suddenly be able to image all sorts of DSOs

[Jeff-Colorado]

An interesting thread. I finally got a good look at M13 with my 8 inch scope under dark skies. It was stunning. It's hard to imagine how star-filled the night skies would be on a planet within that cluster.