Hubble finds appearances can be deceptive

Jan 28, 2013

(Phys.org)—Globular clusters are roughly spherical collections of extremely old stars, and around 150 of them are scattered around our galaxy. Hubble is one of the best telescopes for studying these, as its extremely high resolution lets astronomers see individual stars, even in the crowded core. The clusters all look very similar, and in Hubble's images it can be quite hard to tell them apart – and they all look much like NGC 411, pictured here.

And yet appearances can be deceptive: NGC 411 is in fact not a globular cluster, and its stars are not old. It isn't even in the Milky Way. NGC 411 is classified as an open cluster located in the , a small sister galaxy near our own. Less tightly bound than a globular cluster, the stars in tend to drift apart over time as they age, whereas globulars have survived for well over 10 billion years of galactic history. NGC 411 is a relative youngster—not much more than a tenth of this age. Far from being a relic of the early years of the universe, the stars in NGC 411 are in fact a fraction of the age of the sun.

The stars in NGC 411 are all roughly the same age, having formed at one time from one cloud of gas. But they are not all the same size. Hubble's image shows a wide range of colors and brightness in the cluster's stars; these tell astronomers many facts about the stars, including their mass, temperature and evolutionary phase. Blue stars, for instance, have higher surface temperatures than red ones.

The image is a composite produced from ultraviolet, visible and made by Hubble's 3. This filter set lets the telescope "see" colors slightly further beyond red and the violet ends of the spectrum.

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Caliban
3.3 / 5 (3) Jan 28, 2013

Oh, I thought this cluster was located in the "Strawman Galaxy".

Appearances can be just as deceiving as headlines, one supposes.
SethD
1.7 / 5 (6) Jan 28, 2013
This is one political group trying to undermine another political group, I heard. Both are composed exclusively of physicists, unfortunately.

The grab started around some multimillion deal for a new telescope array or something, if I understood it correctly.

Anywho, these folks don't like that the enemy group got ahead by making observations that make these guys look obsolete with NSF.

LOL
Tuxford
1.6 / 5 (7) Jan 28, 2013
Classification schemes based on faulty assumptions are misleading. Open or closed? Is nature binary? Such is the compelling human need for classifications. Classify it and call it knowledge. What has really been learned?

They call it open, though it looks like a globular? Because they see 'young' stars according to their scheme, which in fact may be older blue stars?

Is this really news?
nkalanaga
5 / 5 (4) Jan 28, 2013
No, the difference is that the stars in an open cluster aren't gravitationally bound to the cluster, but will eventually disperse. In a globular most of the stars are bound, and will only leave the cluster through interactions with other stars.
Tuxford
1.6 / 5 (7) Jan 28, 2013
No, the difference is that the stars in an open cluster aren't gravitationally bound to the cluster, but will eventually disperse. In a globular most of the stars are bound, and will only leave the cluster through interactions with other stars.


And they know most of the stars are not bound with certainty in a cluster outside our galaxy??? Again, a binary answer is all that is allowed? Could it be this cluster is evolving from one to the other, as it resembles both?
yyz
5 / 5 (5) Jan 28, 2013
" Could it be this cluster is evolving from one to the other, as it resembles both?"

From this study of the color-magnitude diagram for NGC 411, the age of the cluster was determined to be 1.5 plus/minus 0.5 Gyr: http://articles.a...ype=.pdf

This isn't exactly unexpected, as young stellar clusters seem to be a regular feature of interacting and merging galaxies, such as the SMC/MWG system:

http://arxiv.org/...10v1.pdf

http://iopscience...ext.html

http://arxiv.org/...47v1.pdf

What's so surprising about seeing young stellar clusters in an interacting galaxy?
Q-Star
3.7 / 5 (6) Jan 28, 2013
What's so surprising about seeing young stellar clusters in an interacting galaxy?


I'm thinking that young stellar clusters will be found to be more common than is conventionally thought,,, with the new generation ground based super-telescopes to come on line in the next decade.

And I lose sleep wishing for them to hurry with the JWST. Delaying it to save money is only driving the costs up. The only thing good about the delay is the extra QC & tweaks they are able to apply to the construction,,,, but I still wish it was already up there on the original schedule.
obama_socks
2.6 / 5 (5) Jan 28, 2013
@Q-Star... I have answered your ?? regarding Pussycat_Eyes in the aurora thread.

The launch of JWST is proposed to go in 5 years. Let's hope it's perfect with no glitches.
Q-Star
3 / 5 (4) Jan 28, 2013
@Q-Star... I have answered your ?? regarding Pussycat_Eyes in the aurora thread.


Yes, I saw it. I thank you and Otto for the input,,,, I'm glad I'm not in that dust up, as Mr. Eastwood would say: "A man's got to know his limitations" and I don't mind admitting that either one of you would eat me alive.

Yeppers, 2018 for something that should have been up now,, and I agree, let it be perfect, they certainly had/have enough time to make it so.

By the By: Does anyone ever consider what it would be like to work your entire productive career on just ONE single project, day-in and day-out for 20 or 30 years, ONE single project. There are people working on the JWST who will retire with that claim to fame.
TheGhostofOtto1923
2.1 / 5 (11) Jan 29, 2013
Yes, I saw it. I thank you and Otto for the input,,,, I'm glad I'm not in that dust up, as Mr. Eastwood would say: "A man's got to know his limitations" and I don't mind admitting that either one of you would eat me alive.
Let me caution you, that engaging with this person only encourages her. Stay tuned for a flood by the fake NASA engineer (contract) explaining how auroras can be used by aliens to communicate, and how NASA has plenty of time to add new equipt to the Hubble. And how zero growth requires zero births. For a hundred years.
TheGhostofOtto1923
1.9 / 5 (9) Jan 29, 2013
Yes, I saw it. I thank you and Otto for the input,,,, I'm glad I'm not in that dust up, as Mr. Eastwood would say: "A man's got to know his limitations" and I don't mind admitting that either one of you would eat me alive.
Let me caution you, that engaging with this person only encourages her. Stay tuned for a flood by the fake NASA engineer (contract) explaining how auroras can be used by aliens to communicate, and how NASA has plenty of time to add new equipt to the Webb (sorry). And how zero growth requires zero births. For a hundred years.
katesisco
3 / 5 (4) Jan 29, 2013
Thinking about the M Clouds and their apparent discrepancy --Let's say there existed in the past a Magellanic spiral galaxy whose nucleus collapsed and exhausted its gas outward. Let's further speculate this event produced a lessening of gravity. Stars wandered off, gas streamed off for greener pastures, globular clusters expanded and became loose clusters. As the gas cooled gravity reasserted itself and what science sees are these weird discrepancies, and of course, the restart of normal, the star nursery of the LMC.
obama_socks
1 / 5 (5) Jan 29, 2013
Yes, I saw it. I thank you and Otto for the input,,,, I'm glad I'm not in that dust up, as Mr. Eastwood would say: "A man's got to know his limitations" and I don't mind admitting that either one of you would eat me alive.
Let me caution you, that engaging with this person only encourages her. Stay tuned for a floord by the fake NASA engineer (contract) explaining how auroras can be used by aliens to communicate, and how NASA has plenty of time to add new equipt to the Webb (sorry). And how zero growth requires zero births. For a hundred years.
-Blotto the lover of all things NAZI

Blotto keeps talking about a "her". Who is this "her" Blotto keeps referring to? Obviously, it's all in Thegoatofotto's wild imagination, brought on by his/her DISSOCIATIVE IDENTITY DISORDER, a mental illness which causes Blotto to create multiple sock puppets to support Blotto for when he talks to himself.
There is NO pussytard...also no Pussycat_Eyes. (contd)
obama_socks
1 / 5 (6) Jan 29, 2013
It is all in Theghostofotto1923's diseased mind. Everybody has noticed that Blotto goes into a thread and starts ranting about how I said this...and I said that...and Blotto floods the whole thread with crap that nobody appreciates or wants to read. And then Blotto misquotes everything I said in another thread because Blotto is aware that very few people will bother to go to the other threads to read what I actually said. That way Blotto can tell as many lies as it wants about what I supposedly said with the intention of getting people to believe its lies.

Blotto makes an excellent Socialist who follows Saul Alinsky's "Rules for Radicals" because most of what Blotto says is based on fabrications meant to intimidate and harass.

Blotto harassed Pussycat_Eyes until she couldn't take it anymore and finally gave up her user name and changed it so that she could enjoy this site in peace.

Theghostofotto1923 is very sick mentally, but I am a patient man who doesn't get offended easily.

FrankHerbert2
2.7 / 5 (7) Jan 29, 2013
Just look at the endless deflections. Everyone knows you're a mental defect, Obama_socks.
rubberman
3 / 5 (4) Jan 30, 2013
The globular clusters in the MW hang in the magnetic field above and below the eclipitic, they don't disperse. The SM cloud has no active galactic nucleus generating a magnetic field strong enough to hold it's clusters together. If these clusters were held together by gravity alone they wouldn't really care where they were or how old they are.
yyz
5 / 5 (3) Jan 30, 2013
"The SM cloud has no active galactic nucleus generating a magnetic field strong enough to hold it's clusters together."

For this (unsupported) statement to be true, you would then need to explain the presence of intermediate-age and old clusters in the SMC: http://iopscience...8/5/1403

Additionally, several dwarf galaxies (with no obvious "active galactic nucleus") are known to harbor old clusters. The Fornax dwarf galaxy has 6 known clusters, 5 of them old: http://en.wikiped...clusters

On the flip side, if the strength of the galactic magnetic field is somehow responsible for holding globular clusters together, you would need to explain the presence of the dozen or so sparse, loose old GCls known in the MWG.

Like the globular cluster NGC 5053 (lower left of M53 in this image): http://4.bp.blogspot.com/-XAz_WknvIDQ/T4JgIy599lI/AAAAAAAAAns/o-_CqWko7EI/s1600/m53_ngc5053_x1240.jpg
rubberman
1 / 5 (1) Jan 30, 2013
YYZ- Your first link actually states that the core radii expands based on the age of the clusters (indicating they spread out with age) and that there is only one "globular" cluster in the SMC (NGC121)which is an eliptical formation (classified based on the age of the stars) . I don't need to explain the age of any cluster as we are talking about maintenance of structure (globular or open), not classification based on age(which is how they classify NGC5053 as globular despite is "loose" arrangement). Which galaxy in the Fornax are we talking? Fornax 4 is the only named GC in the group and there is very little info. about it. NGC1363 and 1398 both display an active nucleus. My unsupported statement provides a mechanism for GC maintenance vs. OC dispersal. I suppose there is some explanation for how DM could be responsible, but clearly I don't have that one.....
TheGhostofOtto1923
1 / 5 (5) Jan 30, 2013
Blotto harassed Pussycat_Eyes until she couldn't take it anymore and finally gave up her user name and changed it so that she could enjoy this site in peace.
Like I said, endless flood of bile. The chance that any 2 people would exhibit identical ignorance such as you and pussytard, is very small indeed. And so we can conclude that you are one and the same.

If pussytard (you) posted under another name, she (you) would be immediately identified. As you have. And as you will be. Your Unique Imbecile Signature (UIS) is impossible for someone as dumb as you, to disguise. Haven't you realized even THIS?

This is a site full of professionals. How could you ever think that you could pretend to be a nurse, or a farmer, or an engineer, HERE?? And why would anyone try, unless something was seriously WRONG with them?
rubberman
1 / 5 (1) Jan 30, 2013
As sidebar YYZ, I think it has as much to do with the field polarity as with the strength. If it is DM, then I would be wrong which I can live with. Better to have the answer than not.
Q-Star
2.3 / 5 (3) Jan 30, 2013
Which galaxy in the Fornax are we talking? Fornax 4 is the only named GC in the group and there is very little info. about it.


Fornax is a dwarf galaxy. Fornax 4 is a globular cluster within the dwarf galaxy Fornax.
Q-Star
3 / 5 (4) Jan 30, 2013
My unsupported statement provides a mechanism for GC maintenance vs. OC dispersal. I suppose there is some explanation for how DM could be responsible, but clearly I don't have that one.....


Not unless the mechanism includes the primary force as gravity. Magnetism is not enough to explain the velocities observed and mass observed. (It won't work like a child's toy magnetic which sticks to an iron object. That is not the mechanisms which holds thing together on large scales.)
rubberman
2 / 5 (4) Jan 30, 2013
Which galaxy in the Fornax are we talking? Fornax 4 is the only named GC in the group and there is very little info. about it.


Fornax is a dwarf galaxy. Fornax 4 is a globular cluster within the dwarf galaxy Fornax.


Yup. My stupidity...sorry. I was reading from YYz's link on GC's...didn't scroll up.
Q-Star
3 / 5 (4) Jan 30, 2013
The globular clusters in the MW hang in the magnetic field above and below the eclipitic, they don't disperse.


For that to be correct, they would all hang together along "lines of force". They don't. They are evenly spread throughout the halo, with orbits moving every which way, with out an overlaying pattern. If they all moved together, along the same lines, in the same directions, with the same mechanics,,,, only then could you possible make a case that some "magnetic" thing was directing. The observations clearly show that this is not the case.
Q-Star
3 / 5 (4) Jan 30, 2013
Yup. My stupidity...sorry. I was reading from YYz's link on GC's...didn't scroll up.


I never find your posts stupid. I disagree with some of the things you seem to support. But it is clear that you THINK. That is refreshing. Thinking is good all the time. I even rate some of your posts 5's that I personally think are tepid or weak,,,, because of the amounting of thinking and reasoning involved in them.

Thinking that you don't really need to think because you think you are so smart that you don't need to think is not so good. And there are way to many people on this site who fall into that group.
rubberman
1 / 5 (2) Jan 30, 2013
Not unless the mechanism includes the primary force as gravity. Magnetism is not enough to explain the velocities observed and mass observed. (It won't work like a child's toy magnetic which sticks to an iron object. That is not the mechanisms which holds thing together on large scales.)


You are correct that it doesn't work like a childs toy, It is far more complicated. Gravity does an even worse job without the mass of it's undetectable partner, which can't be tagged as "observed mass"....only inferred mass. How does gravity maintain a GC without it completely collapsing yet isn't able to maintain an open cluster? The only answer SC has right now is DM. So until DM is actually identified, Magnetism in it's various forms is equally viable (I realize that is in my opinion). Fortunately my career isn't based around this stuff, but if it were a court of law DM isn't even admissable as evidence.

rubberman
1 / 5 (2) Jan 30, 2013
Yup. My stupidity...sorry. I was reading from YYz's link on GC's...didn't scroll up.


I never find your posts stupid. I disagree with some of the things you seem to support. But it is clear that you THINK. That is refreshing. Thinking is good all the time. I even rate some of your posts 5's that I personally think are tepid or weak,,,, because of the amounting of thinking and reasoning involved in them.

Thinking that you don't really need to think because you think you are so smart that you don't need to think is not so good. And there are way to many people on this site who fall into that group.


That's funny, I look back at some of them and think they are pretty freakin sensless. In all seriousness, the only reason I debate against SC and put my eggs in the EM/magnetic basket is it's ability to amplify itself by coupling of fields. If interstellar space is full of magnetic "structures" , the domain walls are where the force is located...con't
rubberman
1 / 5 (2) Jan 30, 2013
...since fields can't be "broken",the heliospheres domain wall which has been shown by voyager measurements to be essentially an enormous magnetic bubble would be suspended in these structures. IF that is the case, DM and these structures could be one in the same. But the galactic halo is a different animal....A2G gets this one better than I as he has done the experiments. Of everything I have read, watched and understand about the properties of magnetism, the relationship between magnetism and gravity seems pretty clear, and makes more sense than anything else I can find.

But thanks Q! Like I said you know your stuff.
yyz
5 / 5 (2) Jan 30, 2013
@rubberman,

What I was trying to get at is why any globular clusters are found in these dwarf and irregular galaxies if such galaxies have "...no active galactic nucleus generating a magnetic field strong enough to hold it's clusters together"? Why is NGC 121 for example, an old globular cluster, found in the SMC at all if the galaxy is lacking a strong galactic magnetic field?

How do globular clusters exist at all in intergalactic space, far from the gravitational influence of any galaxy (AGN or otherwise), if a strong magnetic field is, as you propose, a "mechanism for GC maintenance"?

In short, I don't see the connection between the magnetic field strength in galaxies and the existence (or not) of globular clusters. Globular clusters are known to exist in intergalactic space far from any galaxy.
rubberman
1 / 5 (1) Jan 30, 2013
Missed the comment about the "lines of force" in the galactic Halo. The Andromeda galaxies "satelites" orbit in the co-planar fashion you describe. I have never seen a graphic depicting the ones in the MW but I would love to (I'll check google). It's times like this I am envious of of the tools of your trade. If I can find one and have an opinion, I'll let you know. What I can tell you is the galactic magnetic field is as poorly understood (by most) as the suns was 20 years ago. There are more variables at play and more compounding factors which effect it than are given credit.
Q-Star
3 / 5 (4) Jan 30, 2013
What I can tell you is the galactic magnetic field is as poorly understood (by most) as the suns was 20 years ago. There are more variables at play and more compounding factors which effect it than are given credit.


We are truly in a golden age as far as astronomy, astrophysics and cosmology are concerned... It's almost like we are acquiring TOO MUCH new data, TOO MANY new observations,,,, and we just don't have the computer power or time to assembly it all. Ain't it a wonderful age to live in?

There are at least several hundred billions of galaxies out there, averaging several hundred billions of stars each. And so much stuff we've been able to discover in-between them all. I'm amazed that we can even know just that.

Only a hundred years ago, we were clueless about how the atom might be arranged. We didn't even know about neutrons. We had no good idea what powered the sun. We didn't know there were any other galaxies other than The Galaxy.
rubberman
1 / 5 (1) Jan 30, 2013
@YYZ - I had never heard of a globular cluster not associated with a galaxy (dwarf or otherwise)or galactic cluster. I have no explanation what could hold them together if they are floating around in intergalactic space, far from the influence of any galaxy. (other than admitting that DM is there of course). Do you have a specific cluster in mind?
rubberman
1 / 5 (1) Jan 30, 2013
Agreed Q, this stuff is showing up at a breakneck pace compared to even the 90's. Thanks to you and YYZ for demonstrating how assumptions breed flawed logic, ( I will endeavour to check them when i make them....prior to commenting).
yyz
5 / 5 (2) Jan 30, 2013
" I had never heard of a globular cluster not associated with a galaxy...Do you have a specific cluster in mind?"

There have been studies of intergalactic globular clusters in

Abell 1656(Coma Cluster): http://arxiv.org/...1.1000v2

Abell 1185: http://arxiv.org/abs/1101.5399

as well as unbound GCls in the Virgo and Hydra galaxy clusters. Theoretical studies into the origin and evolution of intergalactic GCls has also been undertaken, e.g.: http://arxiv.org/.../0509744

As far as DM (around clusters) being responsible for keeping GCls bound, several studies of very remote GCls have found little evidence for intrinsic DM halos, e.g.:

http://arxiv.org/abs/1010.5783

http://arxiv.org/abs/1210.7787

As an aside rubberman, I find many of your posts on AGW and so on to be well informed, up to date, with references to the published science (thanks for those). I guess it's some of your astrophysical musings that give me reason to pause from time to time. I'll get over it. :)
Tuxford
1 / 5 (3) Jan 31, 2013
How do globular clusters exist at all in intergalactic space, far from the gravitational influence of any galaxy (AGN or otherwise), if a strong magnetic field is, as you propose, a "mechanism for GC maintenance"?

In short, I don't see the connection between the magnetic field strength in galaxies and the existence (or not) of globular clusters. Globular clusters are known to exist in intergalactic space far from any galaxy.


Indeed, Z, nice question you found. Here is an answer you will not like. Intergalactic clusters grow over time after ejection from a core.

http://phys.org/n...axy.html

And again, why they contain 'old' blues.

http://phys.org/n...ter.html

yyz
5 / 5 (3) Jan 31, 2013
"Intergalactic clusters grow over time after ejection from a core."

The SMC, LMC, Fornax dwarf galaxy and many dwarf irregular galaxies with known clusters have no discernable core (nucleus). Where did their clusters come from?

Got a link to some published work or do you wanna keep making stuff up?
Tuxford
1 / 5 (4) Jan 31, 2013
Some galaxies condense to form early stars, with no initial discernable core. Nevertheless, the first stars that grow big are likely to eventually eject material forming the basis for a new cluster. Why should the universe be binary in nature? LaViolette claims only that some galaxies form from ejected cores, not all. He specifically mentions condensation as another mechanism.

http://phys.org/n...tly.html

http://phys.org/n...ace.html

http://phys.org/n...eas.html

http://phys.org/n...680.html

What career-seeking astronomer can permit these ideas to invade decades of science propaganda? The publication system is self-limiting.