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Why are we so sure that there is a need for dark matter?


Dandav
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12 hours ago, JeffreysTubes8 said:

I have a whole mathematical model in the Historical Codex Thread. I had started my hypothesis in explaining the SMBH formation issue, there were other hypotheses to explain the problem, direct collapse of primordial gas clouds, blue giant stars, etc. However, they don't give time enough to form such large black holes so early in the universe. In my model everything gravitates to one center almost immediately forming SMBHs but these objects themselves can create enough dark energy to prevent the universe from becoming a black hole due to the superluminal gravity within the event horizon proximity and launching galaxies FTL as we observe them to be traveling. -e particles, or even down quarks, would represent the local strength of gravity, the up quarks or positively charged particles would be experiencing similar pulls from another direction due to the higher gravitational frame-drag rate, even though the frame-drag magnitude is infinitesimal to a local source by comparison. So the opposing pull of a local object like the SMBH against dark energy particle collisions from far away forms the first atoms. This is before light is free to move about the cosmos. 

The model's logic base is Murphy's law, a sphere is the product of what can happen in a dimensional body. Infinite spheres are then likely to occur with every possible velocity in every possible direction, and due to the constant of c we observe, these graviton spheres should be about a planck length. So when they make contact they emit a gravity wave which tugs (frame-dragging) everything within the vicinity of the wave by a planck length, then as the wave expands this gravitational magnitude decreases by the inverse square law. A black hole is just many gravitons inseparably combined into one, each time a new graviton combines with the black hole a very strong gravitational wave is released. Inside the eh a graviton that is not combined will continue to move by this frame drag rate of millions or billions of planck lengths in a planck time long after it outraces the expanding gw of the black hole, it is now a dark energy particle. When it collides with another graviton the gw emitted may not pull by more than a planck length, but it will do so in millionths or billionths of a planck time, inverse of the gw that created it, but the effect is the same on an object experiencing this gravity. Fast gravity = strong gravity. Which is why I believe anti-gravity crafts observed, like the Gimbal Video, are real. 

 

11 hours ago, JeffreysTubes8 said:

When I speak of "what is waving between particles" 

http://labman.phys.utk.edu/phys136core/modules/m9/images/dslit.gif

When one sees this the immediate question that comes to mind is, what is waving? What is this particle pond? If particles aren't bullets that is, as originally thought, and they are as observed in that diagram, as a microscopic fluid. Apropos a gravitational fluid. Two up quarks and one down quark, the hydrogen atom, that's a pattern held in place by external gravitational influences converging at a local cosmic region in such a way that it creates the specific structure of a specific type of matter. So in my theory matter is a holoprojection of what's going on at the heart of galaxies and collisions between galaxies - as these forces converge at the spiral discs of the galaxy, or the spherical gas cloud back before the CMB. 

So again all you give is meaningless word salad... still trying to baffle us with bullshit due you having no brilliance.  

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On 12/4/2022 at 8:35 AM, Halc said:

It is known as the winding problem. If all matter stayed in the same arm at all times, moving at the measured velocities, the galaxy shape would very quickly wind up so tight that all structure would be lost, leaving just a disk.

windprob.gif

If the structure retains its general shape over multiple rotations and the stars maintain their general position in that structure, the matter in the galaxy would constitute approximate rigid motion, making the velocity of any star relative to the galaxy a linear function of its distance from the center.

The winding problem is an indication that our scientists have considered a possibility for gravitational arm "where all matter stayed in the same arm at all times".

However, this idea of gravitational arm had been rejected not due to any error in the gravity force that can bond the stars in the arm, but due to the winding problem.

Do you agree with the above?

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5 hours ago, Dandav said:

The winding problem is an indication that our scientists have considered a possibility for gravitational arm "where all matter stayed in the same arm at all times".

There was never a theory of 'gravitational arm'. A galactic arm is a human abstraction, an arbitrary subset of material. There is no valid physics that suggests that an arbitrary subset of matter like that can exhibit gravity in isolation of other gravity. It's like asserting (as you do) that Earth's pull on the moon somehow negates the pull of the sun on it. That was shown to be wrong, despite the fact that the moon tends to stay in Earth's vicinity.

So yes, there was a time when the prevailing view suggested that most stars tended to stay in the same 'arm'. It was never a 'gravitational arm' theory since an abstraction does not have gravity of its own. Each bit of matter everywhere (not just in the galaxy, which is just another abstraction in the end) exerts pull on all other bits. The acceleration of any given particle is due to the sum of these forces, including local interactions through forces other than gravity. An arm isn't a mass at a location, so it adds nothing to the above description.

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11 hours ago, Halc said:

So yes, there was a time when the prevailing view suggested that most stars tended to stay in the same 'arm'.

When was it and why the stars tend to stay together in the arm?

11 hours ago, Halc said:

There is no valid physics that suggests that an arbitrary subset of matter like that can exhibit gravity in isolation of other gravity.

is it?

Please look carefully at the following image:

hubble_arp248_potw2244a.jpg

https://www.nasa.gov/image-feature/goddard/2022/hubble-inspects-a-pair-of-space-oddities

Do you confirm the following:

1. We observe dual spiral galaxies.

2. Each galaxy has two spiral arms while each arm is located exactly at 180 degrees from the other arm.

3. Mutual gravitational attraction - It is stated: "This elongated stream of stars and interstellar dust is known as a tidal tail, and it formed by the mutual gravitational attraction of the two foreground galaxies."

Therefore, do you agree that the bridge is all about two arms that are connected/interact to each other by gravity force?

5. Please look at the other arm of each galaxy - Do you agree that it is located exactly on the other side? Therefore, can we agree that the other arm is due to tidle gravity force?

7. T-hold time = The time duration for that mutual gravitational attraction, (or how long this structure of "mutual gravitational attraction" could live in total)?

Few thousands of years, few million years or you are sure that this Mutual gravitational attraction had been formed yesterday and it will break down by tomorrow morning?

8. Do you confirm that during T-hold time the spiral arms of each galaxy can't rotate anymore?

9. Do you agree that as long as the two galaxies are connected by their mutual gravitational attraction in one arm, then the other arm can't move.

10. If the answer is yes - then why can't we claim that those two arms in each galaxy are gravitational arms?

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I cannot give human designated subsets of matter special physics properties. The mathematics would be violated if this was done. Answers are therefore given in this light since you are attempting to give special physical properties to abstract concepts.

6 hours ago, Dandav said:

1. We observe dual spiral galaxies.

That is a matter of human designation. One person might see a single structure and others more. Most people would, in that picture, say that it is two interacting galaxies, but how the material evolves has absolutely nothing to do with this human opinion.

6 hours ago, Dandav said:

2. Each galaxy has two spiral arms while each arm is located exactly at 180 degrees from the other arm.

I count 7 arm-ish things. Two yellowish arms each for the galaxies (which you apparently don't see at all), plus more bluish material somewhat ejected to the upper left and lower right of the picture, plus the bridge between them. Only the yellow ones are the usual rotating arms. The blue concentrations of material are the tidal tails, not arms at all. You obviously label them differently, which is fine until you start giving special physical properties to your designation.

6 hours ago, Dandav said:

3. Mutual gravitational attraction - It is stated: "This elongated stream of stars and interstellar dust is known as a tidal tail, and it formed by the mutual gravitational attraction of the two foreground galaxies."

That's what the article says, yes. No disagreement until you start denying mutual gravitation with all the other galaxies as well.

6 hours ago, Dandav said:

Therefore, do you agree that the bridge is all about two arms that are connected/interact to each other by gravity force?

No You forgot to number this one as '4'. You also forgot 6 altogether.

6 hours ago, Dandav said:

5. Please look at the other arm of each galaxy - Do you agree that it is located exactly on the other side? Therefore, can we agree that the other arm is due to tidle gravity force?

I presume you're talking about the outside extensions of the bluish tidal material. They don't have an exact location since the material is spread out, so it is meaningless to say 'exactly on the other side'. All the bluish material is where it is largely due to tidal effects, as the article states. It's a classic tidal signature, just like the one the moon gives Earth.

6 hours ago, Dandav said:

7. T-hold time = The time duration for that mutual gravitational attraction, (or how long this structure of "mutual gravitational attraction" could live in total)?

Gravitation attraction never stops. There's nothing about a time limit in the equations.

6 hours ago, Dandav said:

8. Do you confirm that during T-hold time the spiral arms of each galaxy can't rotate anymore?

There is no T-hold time. The yellow actual arms continue to rotate as before. Watch the simulations which make it a lot clearer than a single still shot, but careful because most simulations use unrealistic rotation curves to simplify the programming. Simulations of realistic density waves are more compute intensive and rarely have collisions added in.

6 hours ago, Dandav said:

9. Do you agree that as long as the two galaxies are connected by their mutual gravitational attraction in one arm, then the other arm can't move.

All galaxies are effected by each other's mutual gravity. If you call that a connection, then that connection lasts forever. The blue material in the tidal clouds have little effect on the rotation of the galaxies which just keep right on spinning after a close encounter like this. The pattern would probably be more disrupted with a more direct hit, but this wasn't a very direct hit. Angular momentum is always conserved.

6 hours ago, Dandav said:

why can't we claim that those two arms in each galaxy are gravitational arms?

You can call them anything you want. The term is reasonably undefined in celestial mechanics, so sans a definition, you'd just be making a statement that's not even wrong.

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19 hours ago, Halc said:

.

On 12/7/2022 at 3:09 PM, Dandav said:

3. Mutual gravitational attraction - It is stated: "This elongated stream of stars and interstellar dust is known as a tidal tail, and it formed by the mutual gravitational attraction of the two foreground galaxies."

That's what the article says, yes. No disagreement until you start denying mutual gravitation with all the other galaxies as well.

On 12/7/2022 at 3:09 PM, Dandav said:

Therefore, do you agree that the bridge is all about two arms that are connected/interact to each other by gravity force?

No 

Why No?

You confirm that there is "Mutual gravitational attraction", then based on your understanding what is the meaning of that gravitational attraction and tidal tail?

What kind of force could form  "This elongated stream of stars and interstellar dust is known as a tidal tail" / Bridge?

Is it some kind of dark force due to dark matter or just a simple gravity force?

As you claim that Gravitation attraction never stops

19 hours ago, Halc said:
On 12/7/2022 at 3:09 PM, Dandav said:

7. T-hold time = The time duration for that mutual gravitational attraction, (or how long this structure of "mutual gravitational attraction" could live in total)?

Gravitation attraction never stops. There's nothing about a time limit in the equations.

Then do you agree that this bridge could last for very long time?

What about the other arm of each galaxy?

While one arm is locked in that bridge between the galaxies, do you claim that the other free arm should continue to rotate?

19 hours ago, Halc said:

Simulations of realistic density waves are more compute intensive and rarely have collisions added in.

I have asked you in the past and I will ask you again:

How the density wave + dark matter could form the unique structure of spiral galaxy?

Bulge: 0 - 1KPC

Bar: 1KPC - 3KPC

Ring - 3KPC

Spiral arms: 3KPC - 15KPC. 

Diameter of spiral arms: at 3KPC - 3000LY, at our location - 1000LY, at 15KPC - 400LY

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On 12/6/2022 at 8:51 AM, Moontanman said:

 

So again all you give is meaningless word salad... still trying to baffle us with bullshit due you having no brilliance.  

They're not empty words, for one there's a graph that can make particles like these. And second, early SMBH formation and expansion are not well explained by the standard model. Lastly, the hypothesis can be tested and probably will be. I.E. fast gravity, this is why I'm getting an engineering degree, so I can know how to build a test. 
 

Where here are the criteria of a fundamental theory not met? For example, disorganization in the skeleton of the graphical arithmetic doesn’t count, but an error would. If it is intended to be tested that is the only area where it would fall short, if it hasn’t been experimentally proven it is still a fundamental theory.

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6 hours ago, Dandav said:
On 12/7/2022 at 8:09 AM, Dandav said:

Therefore, do you agree that the bridge is all about two arms that are connected/interact to each other by gravity force?

Why No?

I would not agree to a meaningless statement. "Is all about" is not a meaningful term in this context. Physical objects are not meaningfully 'about' something, be it 'all about' or just partially about. So I have no clue what you're suggesting with your statement let alone enough to agree with it.

6 hours ago, Dandav said:

based on your understanding what is the meaning of that gravitational attraction and tidal tail?

Physics does not give meaning to celestial objects. Astrology maybe does. Go ask them.

6 hours ago, Dandav said:

While one arm is locked in that bridge between the galaxies, do you claim that the other free arm should continue to rotate?

Nothing is locked. You are again trying to give rigid properties to what is essentially an effect.

6 hours ago, Dandav said:

How the density wave + dark matter could form the unique structure of spiral galaxy?

Dark matter has little to do with it. A galaxy with little to no dark matter will still show structure. A galaxy with little to no baryonic matter will not. This tells me that gravity alone is not enough, so in attempt to use your phrase, it isn't 'all about' gravity.

As for the density wave hypotheses, there is more than one model. They're not my models. Read up on them. I'm not a cosmologist, but the simulations I've seen from them look a lot more like real galaxies than do the simplified ones.

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On 12/9/2022 at 12:51 AM, Halc said:

Dark matter has little to do with it. A galaxy with little to no dark matter will still show structure. A galaxy with little to no baryonic matter will not. This tells me that gravity alone is not enough, so in attempt to use your phrase, it isn't 'all about' gravity.

Are you sure that "it isn't 'all about' gravity"?

Why our scientists have invented the dark matter idea?

Don't you agree that it was due to the impact of gravity on the Rotation Curve problem in the Galaxy?

 

Rotation_curve_eqs.jpg

 

Rotation following Kepler's 3rd law is shown above (blue) as planet-like or differential rotation. Notice that the orbital speeds falls off as you go to greater radii within the Galaxy. This is called a Keplerian rotation curve.

However, in order to keep the flat orbital velocity dark matter is needed.

Never the less, we can't just take dark matter and set it in the galaxy.

It is much more complicated as the dark matter density isn't constant in the galaxy.

For any galaxy at any radius there is a need for different dark matter density.

Therefore, if the spiral galaxy wish to keep its galactic orbital velocity, it needs a specific density of dark matter at any radius.

How galaxies can set so complicate calculation for the requested dark matter density?

Do they have  some sort of built in computer in order to calculate the requested dark matter formula?

Even if they can do it, don't you agree that at the end of the day dark matter is all about adding missing gravity force in the galaxy?

Therefore, why can't you agree that even the dark matter is all about gravity?

However, the dark matter can ONLY help the galaxy for the Rotation Curve problem

Unfortunately, it can't offer any solution for the complexity of spiral galaxy.

On 12/9/2022 at 12:51 AM, Halc said:

As for the density wave hypotheses, there is more than one model. They're not my models. Read up on them. 

Sorry, you don't have real theory that can deeply explain the full structure of spiral galaxy.

You don't know why the Bulge has a sphere shape while as we go further away from the we get the disc shape.

You don't know the real functionality of the bar and how it works,

You don't know why there is a ring.

You don't know why there are two main symmetrical arms that are connected to the ring exactly at the other side of the ring. If there are other arms which are connected to the ring, then they must come in a pair & be symmetrical to each other

You don't know why the spiral arms are so massive at their base (3000LY) while at the edge their diameter is only 400LY.

Not the density wave, not the MOND and not any other imagination that our scientists may invent can solve those questions.

 

On 12/9/2022 at 12:51 AM, Halc said:

I'm not a cosmologist, but the simulations I've seen from them look a lot more like real galaxies than do the simplified ones.

Based on my understanding all simulations start with a disc shape galaxy.

If this is the case, then this isn't realistic starting point.

In the following article it is stated:

https://www.smithsonianmag.com/smart-news/supercomputers-create-beautiful-simulations-spiral-galaxies-180963462/

"According to the Auriga Project website, other attempts to simulate galaxy formation have resulted in galaxies that weren’t quite right—from weird bulges to unusual spins that didn’t conform to the what astronomers observe in the skies." 

Hence, they admit that there are fatal problems with the simulations

Never the less, they have added new idea that is called magnetic fields

"The new project attempted to correct those mistakes by adding in elements other simulations did not model, especially the magnetic fields, or did not have the processing power to compute."

However, the main idea of the dark matter is that it can ONLY affects the gravity.

So how come that they have invented that magnetic fields?

I claim that this message proves that the simulation can't offer real solution.

Even so, at the best case, that spiral shape can live for just short time during the simulation.

Sonner or latter if you keep on with the simulation you loose the spiral shape.

However, we know that 70 % of the galaxies are spirals.

Therefore, they must live for billions of years.

As the simulation can show a spiral image for very short time, then this simulation is not realistic.

At the best case, the simulation can only give a brief highlight for the spiral arms shape.

Therefore, do you agree that the best simulation can't really represents the full structure of spiral galaxy (especially not the Bar, not the density of stars in spiral arms and even not the thickness of the spiral arms as we go further away in the radius)?

Therefore, why do you insist to reject the idea that the sun is interacted by gravity to the Orion arm and go with the arm wherever it goes?

If you would know that by accepting this simple idea you would understand how the entire spiral galaxies in the Universe really works with all their unique structure and without any need for dark matter would you continue to reject it?

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4 hours ago, Dandav said:

Notice that the orbital speeds falls off as you go to greater radii within the Galaxy. This is called a Keplerian rotation curve.

Keplerian orbits don't apply to galaxies since galaxies are not single primary masses like our own solar system. What's missing from your graph is the line showing what the curve should be given just the baryonic matter. Many similar graphs show that, but the one you've chosen does not.

4 hours ago, Dandav said:

if the spiral galaxy wish to keep its galactic orbital velocity

Galaxies don't make wishes.

4 hours ago, Dandav said:

How galaxies can set so complicate calculation for the requested dark matter density?

Galaxies don't make calculations. No requests are made of them. What's with the anthropomorphism all of a sudden?

4 hours ago, Dandav said:

Sorry, you don't have real theory that can deeply explain the full structure of spiral galaxy.

That's right. I'm no physicist. They're the ones with the real theories. The bulge/disk is pretty easy to explain. To get an explanation of the bar and such, you need to read up on the current models. I'm not doing it for you, but none of them are based only on assertions. I've not seen a viable MOND model.

4 hours ago, Dandav said:

Based on my understanding all simulations start with a disc shape galaxy.

Your understanding is very likely wrong then. A simulation of how a galaxy maintains its apparent structure would start with the structure. A simulation of galaxy formation would not start with a galaxy already formed.

4 hours ago, Dandav said:

So how come that they have invented that magnetic fields?

They were not invented. They were noticed far before galaxies were noticed.

5 hours ago, Dandav said:

However, we know that 70 % of the galaxies are spirals.

Therefore, they must live for billions of years.

Non sequitur

5 hours ago, Dandav said:

Sonner or latter if you keep on with the simulation you loose the spiral shape.

Many maintain it indefinitely

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17 hours ago, Halc said:
22 hours ago, Dandav said:

Sorry, you don't have real theory that can deeply explain the full structure of spiral galaxy.

That's right. I'm no physicist. They're the ones with the real theories. The bulge/disk is pretty easy to explain. To get an explanation of the bar and such, you need to read up on the current models. I'm not doing it for you, but none of them are based only on assertions. I've not seen a viable MOND model.

As you aren't physicist how do you know how spiral galaxy really works?

Let's focus on the Bar.

In the following article it is stated:

https://www.nasa.gov/mission_pages/hubble/science/bar_galaxies.html

"Bars form when stellar orbits in a spiral galaxy become unstable and deviate from a circular path. "The tiny elongations in the stars' orbits grow and they get locked into place, making a bar," explained team member Bruce Elmegreen of IBM's research Division in Yorktown Heights, N.Y. "The bar becomes even stronger as it locks more and more of these elongated orbits into place. Eventually a high fraction of the stars in the galaxy's inner region join the bar."

Therefore, our scientists clearly understand that somehow stars get locked in the Bar.

However, they don't really explain how that process works and what kind of glue is needed to lock the stars in the Bar?

Is it some sort of dark glue or magic glue?

Don't you agree that simple gravity force is needed to lock the stars to the Bar (without any need for dark matter or dark glue)

In order to make it clear:

Gravitational arm = when stars are locked together by gravity force to the arm.

Therefore, the bar is also some form of gravitational arm.

However, instead of spiral arm it is a very linear gravitational arm.

We can consider it as some sort of globular clusters of stars that are locked together by gravity force, however, instead of spherical shape it has a bar/arm shape.

Hence, why is it so difficult for those scientists to say clearly that the Bar is a linear gravitational arm where all that stars are locked to the bar by gravity force?

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On 12/10/2022 at 9:15 AM, Dandav said:

Therefore, why do you insist to reject the idea that the sun is interacted by gravity to the Orion arm and go with the arm wherever it goes?

If you would know that by accepting this simple idea you would understand how the entire spiral galaxies in the Universe really works with all their unique structure and without any need for dark matter would you continue to reject it?

Why are you in a panic just from the thought that stars could be locked to the bar or to the spiral arm by simple gravity force and go with it where ever it goes? 

What might happen to the MY galaxy if our scientists would finely understand that for its proper operation, gravity is good enough and there is no need for dark matter?

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14 hours ago, Dandav said:

In the following [NASA] article it is stated:

"Bars form when stellar orbits in a spiral galaxy become unstable and deviate from a circular path. "The tiny elongations in the stars' orbits grow and they get locked into place, making a bar," explained team member Bruce Elmegreen of IBM's research Division in Yorktown Heights, N.Y. "The bar becomes even stronger as it locks more and more of these elongated orbits into place. Eventually a high fraction of the stars in the galaxy's inner region join the bar."

Therefore, our scientists clearly understand that somehow stars get locked in the Bar.

Nicely explained there. More than I knew. The stars in the bar may actually stay in the bar if that's right. It would explain the arms too then, similar to the wake of a turning bar in water. The bars don't move around the galaxy at all, but rather outward just like the water waves do.

That's not a statement of fact, just an observation of mine that seems to make sense to me.

14 hours ago, Dandav said:

However, they don't really explain how that process works and what kind of glue is needed to lock the stars in the Bar?

You persist in your rigid object model, which contradicts the quote you gave which says that stars move about within the bar. That much I've definitely read before in other places.

14 hours ago, Dandav said:

Don't you agree that simple gravity force is needed to lock the stars to the Bar (without any need for dark matter or dark glue)

Can't agree with that (or anything with which you ask me to agree). Dark matter is probably not needed, and dark glue is just something you made up. There's no glue at all. But more than gravity is involved, as I've said repeatedly in prior posts.

14 hours ago, Dandav said:

Gravitational arm = when stars are locked together by gravity force to the arm.

OK, at least now I have a definition of sorts for what you mean by that. No, by that definition, a gravitational arm directly contradicts observations, which you'd notice if you actually worked out the mathematical implications your assertions, all of which have been pointed out above.

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8 hours ago, Halc said:
23 hours ago, Dandav said:

However, they don't really explain how that process works and what kind of glue is needed to lock the stars in the Bar?

You persist in your rigid object model, which contradicts the quote you gave which says that stars move about within the bar. That much I've definitely read before in other places.

Why do you claim for rigid object?

I compare the Bar to a star cluster.

In that cluster there could be Millions of stars that are locked together by GRAVITY FORCE, while each star can move about within the cluster.

There is no need for any kind of dark matter to lock the stars in the cluster.

Therefore, do you claim that under this definition a star cluster should be consider as a rigid object?

I hope that you agree that a cluster isn't a rigid object as the bar shouldn't considered as a rigid object.

Therefore, let's agree that gravity is the ultimate force that is needed for "stars to move about within the Bar" as they can also move about within the star cluster.

However, there is a difference in the shape between the two objects.

While the cluster has a spherical shape, the bar has a bar shape.

Our mission is to understand why the Bar that technically works similarity as star cluster got its bar shape.

In order to understand that issue, lets look at the following image of the Milky way:

Milky_Way_Arms-sketch-with-4-major-arms-

This image is based on real observation (and I didn't draw it by myself) - what we see is what we have!

Do you see those dots/tiny bars in the arms?

Do you agree that technically each dot could be a star cluster with millions of stars that are locked to the cluster while they all  move about within the cluster?

However, as there are quite many clusters in each arm, then each cluster is effected by gravity in both sides.

Therefore, instead of a simple spherical dot we actually got those tiny bar shape.

However, if we could take out one tiny bar from the arm and put it somewhere in the open space we would immediately get a simple star cluster.

Please remember that around the bar there is a Ring.

That ring generates some gravity force.

Therefore, why can't we consider the bar as some sort of star cluster that got its bar shape due to the impact of the Ring gravity force?

In the same token, why can't we consider the spiral arm as many star culsters that are locked together one after the other by gravity force in a long line?

Hence, the Bar and the spiral arms might look rigid but they aren't rigid as stars can move about within them.

This can also explain the motion of stars around us.

TCP_01_15.jpg

We see that each star is moving in a different direction but they wouldn't collide with each other and they would stay/locked together due to gravity force!

Don't you agree that this is exactly the expected motion of stars in a star cluster?

There are exactly 64 stars per 50 LY sphere around the Sun and 512 stars in a 100LY sphere.

As the diameter of the arm in our location is 1000LY (and based on the above density of stars), why can't we claim that this 1000LY diameter represents a star cluster with 512,000 stars while the sun with all the other nearby stars move about within that cluster?

 

 

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21 minutes ago, Dandav said:

There is no need for any kind of dark matter to lock the stars in the cluster.

Yes, but dark matter wasn't posited to explain why stars stay with their arms, especially since they obviously don't. Yes, stars are gravitationally bound to (they have negative mechanical energy relative to) their star cluster. Star clusters don't need glue, and my comment was about the glue comment.

25 minutes ago, Dandav said:

Our mission is to understand why the Bar that technically works similarity as star cluster got its bar shape.

It was actually explained quite nicely by the nasa quote you gave.

28 minutes ago, Dandav said:

Do you see those dots/tiny bars in the arms?

Do you agree that technically each dot could be a star cluster with millions of stars that are locked to the cluster while they all  move about within the cluster?

You mean those soap-bubbly things here and there? Those are H II regions, areas of high star formation activity. They're not clusters, nor are the oval shapes containing some of the bubbles. The picture does not identify any star clusters. Surely there's a map of them you can find.

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1 hour ago, Halc said:
2 hours ago, Dandav said:

Our mission is to understand why the Bar that technically works similarity as star cluster got its bar shape.

It was actually explained quite nicely by the nasa quote you gave.

No, there is no real explanation.

Let's Read it again:

"Bars form when stellar orbits in a spiral galaxy become unstable and deviate from a circular path. "The tiny elongations in the stars' orbits grow and they get locked into place, making a bar," explained team member Bruce Elmegreen of IBM's research Division in Yorktown Heights, N.Y. "The bar becomes even stronger as it locks more and more of these elongated orbits into place. Eventually a high fraction of the stars in the galaxy's inner region join the bar."

Let's look at the bulge.

There are millions or even billions of stars over there.

Most of them don't have a circular orbital path.

We can clearly see the un circular path in the S stars motion:

The orbits of four S stars, including S62 (red), around the Milky Way’s central supermassive black hole. The dots are observed positions, and the lines are the calculated orbits. The black hole is at the small black line in the center of the displayed coo

Therefore, when stellar orbits in a spiral galaxy become unstable and deviate from a circular path, it should set a spherical shape and not a Bar shape!

If those scientists were correct, then:

1. Why the bulge has no Bar shape?

2. Why the bar is always located between the Bulge to the Ring?

3. Why the Bar NEVER continue after the ring?

Can you please answer the above questions?

Unfortunately, those scientists totally ignore the key function of the ring.

They do not even consider that the bar is there due to the gravity force impact of the ring.

Actually, if they were correct and the ring has no impact, then technically we should see a bar structure even if there were no spiral arms and no ring.

Why do you think that the Bar has so symmetrical structure.

Don't you agree that this symmetrical structure is due to tidal force?

However, tidal with what?

Why not a tidal force with the ring?

Therefore, the ring gravity is vital for the bar structure.

Hence, stellar orbits in a spiral galaxy become unstable and deviate from a circular due to the ring gravity impact and therefore, we get the bar structure.

If you eliminate the ring and the spiral arms you won't get a symmetrical bar shape and it would be just a spherical shape.

Can you please offer even one Bar galaxy in the entier universe without ring and its spiral arms?

Edited by Dandav
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