[Dave Lev (OP)]

Hello
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Quote from: Dave Lev on 04/07/2022 07:27:58
The outwards section of the bar is located at the same radius as the most inwards side of the spiral arms.
Therefore, this answer is clearly incorrect.

That would be the location at which gravitational dominance switches from that of normal matter to that of dark matter.
Take a look at figure 22 on this page: https://ned.ipac.caltech.edu/level5/Sept16/Sofue/Sofue4.html
The mass contribution of the dark halo begins to dominate the other forms of mass between 1 and 10 kiloparsecs. Inside of that, the other, normal parts of the galaxy make up greater mass contributions. At about 100 parsecs, the bulge appears to have over 10 times the mass contribution of the dark halo.

Please look again at figure22
https://ned.ipac.caltech.edu/level5/Sept16/Sofue/Figures/figure22.jpg

The dark matter influence is described by the black line that is called - direct mass sphere (and a similar red line that is called - flat disc) and it starts from 10^-3 KPC. (which means 1PC = 3.2 LY)
Therefore, the dark matter has neglected impact till about 3LY.
Up to this 3LY range the gravity impact is mainly due to the Black hole.
Therefore, based on the graph the dark matter has an impact From that 3LY (10^-3 KPC) upwards.
So yes, your following message is correct:

The mass contribution of the dark halo begins to dominate the other forms of mass between 1 and 10 kiloparsecs.

However, the bar is located from 1KPC to 3KPC.
Therefore, this graph fully supports my message that the bar is dominated by the mass contribution of the dark halo/matter.
We already know that based on Kepler's third law, in the bar (from 1KPC to 3KPC) there is no need for the dark matter at all.
Hence, the existence of dark matter in the bar violates Kepler's third law!
When we try to focus on the edge of the bar (3KPC), where the ring is located and the spiral arm starts, we don't see any change is the dark matter line.

Quote from: Dave Lev on 04/07/2022 07:27:58
However, you refuse to understand how the ordinary matter can fully explain the rotation curve anomaly.

I'm not refusing to understand it, it's just that it doesn't work. It violates Kepler's third law.

Sorry, you are.
I have just proved that the existence of dark matter in the bar fully violates Kepler's third law.
So, the dark matter imagination clearly can't work!
I hope that you agree that the dark matter can't explain the full structure of the spiral galaxy.
It can't explain why the ring is at 3KPC, why the bar is always inwards to the ring and the spiral arms are always outwards to the ring.
Actually, if you take this graph and run it in the the computer, the chance to get back the structure of the spiral galaxy (Bulge, Bar, ring, spiral arms)  is purely ZERO!
You know it and anyone knows it.

There is a limit on how fast the gravity from normal matter can make the stars orbit. That limit is represented by Kepler's third law.

Sorry, there is no limit.
You all miss the key functionality of the arms in the galaxy (Bar, ring or spiral). Yes the ring is also an arm!!!
You refuse to understand that once the star is bonded to the arm (in the Bar, Ring, or spiral), it must go wherever the arm goes.
Any attempt to look on individual star that is located in the arm (and is gravity bonded to the arm), and try to calculate its velocity as there is no arm - is a FATAL mistake!!!
Hence, when you base the star orbital velocity on the imagination that the arm has no impact, you made a sever mistake that leads you to wrong conclusions - which is:

It violates Kepler's third law.

Sorry, No!
Unfortunately, you refuse to understand that ONLY the arm is responsible for the velocity of the stars that it carry with it.
You keep holding the dark matter imagination which clearly violates Kepler's third law in the bar, just to explain the orbital velocity of stars that are bonded to the arm while it can't explain the full structure of the spiral galaxy.
This is your severe mistake!

Please look at the following image of the Milky way:
https://www.researchgate.net/figure/Schematic-view-of-the-spiral-arms-of-the-Milky-Way-Georgelin-Georgelin-1976-with-the_fig1_23795669
Please, Please try to assume that all the arms are based on stars that are bonded by gravity.
I claim that the mutual gravity force of ordinary matter as stars and gas form the arm structure.
If you don't accept it, then please assume for just one moment that the dark matter is used as an extra bonding element between the stars in the arm (even if if there is no need for that imagination).
In any case, let's agree that we start our explanation about the spiral galaxy while each arm is all about stars that are bonded by gravity (with or without dark matter or dark glue).

Therefore, the ring, Bar and spirals arms are all about stars that are bonded together by their mutual gravity force..
Are you ready to stop the No No NO messages and let me explain how real spiral galaxy works?
Please don't try to show why there is an error in my explanation before you fully understand how the full spiral galaxy structure really works.
I feel as a teacher in a class room where the students don't want to listen and claiming No No no.... on every message that I try to deliver.
Is there any possibility for them to understand my message?
So please. even if you are sure that my explanation is incorrect, would you kindly try to be positive, assume that each arm in the galaxy is all about stars that are bonded together by their mutual gravity force and let me offer full explanation about spiral galaxy based on the steps that I select?
Please...

I wish to start with the ring as this is the most important element in the spiral galaxy!
At the end of my explanation, you are more than welcome to compare this explanation to the dark matter imagination and decide which one is superior and which one really violates Kepler's third law.
Agree?

[Bored chemist]

I have just proved that the existence of dark matter in the bar fully violates Kepler's third law.

No.
You proved that you didn't understand it.And we already knew that.

[Kryptid]

Please don't try to show why there is an error in my explanation before you fully understand how the full spiral galaxy structure really works.

If part of your idea breaks the laws of physics, then the whole idea is going to be wrong too.

This discussion is obviously just going around in circles with nothing being accomplished. I'm done.

[Dave Lev (OP)]

This discussion is obviously just going around in circles with nothing being accomplished.

This discussion is very important as we have accomplished key understanding - The dark matter is incorrect theory.
We have already proved that there is no need for Dark matter in the Bar.
The orbital velocity of stars in the bar can be fully explained by the shape of the bar.
Therefore, the existence of the dark matter in that bar violates Kepler's third law.

I hope that by now we also fully agree that the dark matter by itself can't explain the full structure of the spiral galaxy.
At the best case it can only offer an answer for the orbital rotation velocity of stars in the spiral arms section, but it doesn't give an explanation why there are spiral arms in the disc, why there is a ring, why the bar is always inwards to the ring while the spirals arms are always outwards and many other key questions about the spiral galaxy shape.
We know that 70% of the 400 Billions galaxies in the visible universe are spirals galaxies. ( = 280 Billions)
Therefore, there must be a mechanism that can force/set those 280 Billions galaxies in that specific spiral shape.
I hope that by now we understand that this Mechanism can't be base on dark matter.
Therefore, as the dark matter can't give an answer for the complex shape of the spiral galaxies, it is clear that this dark matter theory is incorrect.

I'm done.

Please don't be upset because of the dark matter.
The science community should be glad to understand that the dark matter is incorrect.
It is much better for the science community to abandon wrong theory and stay without any theory instead of holding an error one in their hand.

If part of your idea breaks the laws of physics, then the whole idea is going to be wrong too.

Even if you would find that my explanation about the spiral galaxy is incorrect, the science community must abandon the dark matter imagination.
Somehow, the science community must look for better theory which can explain the existence of those 280 Billions spiral galaxies just in the visible universe.
As the dark matter can't explain the full shape of spiral galaxy (Bulge, Bar, Ring, Disc, Spiral arms... ) - that dark matter imagination should be abandon and the sooner is better.
Therefore, please don't be upset.
It might be small step for us, but it is a big step for the science community.

[Kryptid]

Please don't be upset because of the dark matter.

I'm not upset. I'm just done trying to do the impossible.

It might be small step for us, but it is a big step for the science community.

Nothing of note has been accomplished in this thread.

[Dave Lev (OP)]

Nothing of note has been accomplished in this thread.

Yes it is.
At least, do you agree that the dark matter can't explain the complex structure of spiral galaxy?
Yes or no please?

On the other hand, there is clear OBSERVATION that the Bar arm and the spiral arm are temporarily connected by "their mutual attraction due to gravity" and "move as one".

I have just found an excellent article about the Bar:
https://scitechdaily.com/galactic-bar-paradox-a-mysterious-and-long-standing-cosmic-conundrum-resolved-in-cosmic-dance/
It is stated:
"The bar pulsations result from its regular encounters with the Galactic spiral arms, in what can be described as a “cosmic dance”. As the bar and spiral arm approach each other, their mutual attraction due to gravity makes the bar slow down and the spiral speed up. Once connected, the two structures move as one and the bar appears much longer and slower than it actually is. As the dancers split apart, the bar speeds up while the spiral slows back down."
It is specifically stated: "their mutual attraction due to gravity makes the bar slow down and the spiral speed up."
It is also stated: "Once connected, the two structures move as one"

So it is all about gravity that connects the stars in the Bar to those in the spiral arm so they all become one.
Wow!!!
What a great information!!!
I was looking for that information for years.
This is the smoking gun of the spiral galaxy!

Not gravity between dark matter to ordinary matter but gravity between two key elements (Bar and spiral arms) in the spiral galaxy that are all based on ordinary matter as stars.
If our scientists would understand the real meaning of this explanation, they would verify that there is no need for dark matter. The stars (ordinary matter) in each element in the galaxy are good enough to maintain its full structure (Bulge, Bar, Ring, Spiral arms...) without any need for even one particle of dark matter!
Take out one element from that complex and you break down the galaxy.
Nothing would help - not even dark matter.

This isn't imagination.
It proves that the "mutual attraction due to gravity" between the ordinary matter (stars and gas) at the edge of the Bar to the ordinary matter in the base of the spiral arm can bond them together and "move as one".
Therefore, we have a clear observation for the bonding impact of the "mutual attraction due to gravity" between stars and gas in the arms (which is all about - ordinary matter).
There is no need for dark matter to bond the stars and gas in the bar to the stars and gas in the spiral arm.
It is all about "mutual attraction due to gravity" of stras and gas between the arms.
In the same token, why the same "mutual attraction due to gravity" of stras and gas that works so perfectly between the arms can't work also in each arm?
Therefore, this is clear observation that stars and gas in each arm can bond themselves by thier "mutual attraction due to gravity" in order to form the arm shape (Bar arm, ring arm and spiral arm).
Once we accept that simple observation, we can easily solve the enigma of spiral galaxy without any need for dark matter.
Each moon goes wherever its planet goes, as each planet goes wherever its star/Sun goes, as each star in the arm goes wherever its arm goes and as each arm goes wherever the galaxy goes.
280 Billions of spiral galaxy - do not make any mistake as they do not need any dark matter. They all base on "mutual attraction due to gravity".

So simple as it is!

[Dave Lev (OP)]

So how spiral galaxy really works:

Any arm in the spiral galaxy (bar arm, ring arm & spiral arm) is based on "mutual attraction due to gravity" between the stars and gas in that arm.
However, the Ring arm is the most important arm in the spiral galaxy.
There are many spiral galaxies without bar arm, but in order to have the bar, they must have the ring (even if it is thin and difficult to be fully observed).
The ring arm is the boundary between the bar arm to the spiral arm.
From outside, it generates the gravity force that holds the base of the spiral arms.
From inside it generates the gravity force that is needed to pull stars from the bulge and form them together in the bar shape by their "mutual attraction due to gravity".
The stars in the Bar arm, would be delivered to the spiral arms and to the ring while the spiral arm would be drifted outwards.
In this way, the structure of the entire spiral arms would be kept even while stars in the spiral arms are drifting outwards.
That drifting outwards movement of the stars in the spiral arms can keep them all in a relatively constant orbital velocity while they increase their radius around the galactic disc. In the same token the spiral arm would keep them all in the galactic disc and they would have to go wherever the spiral arm goes.
As the star gets to the edge of the spiral arm it would be ejected from the arm and from the galactic disc.
Please be aware that there might be a possibility for bridges and gateways between the spiral arms.
A star can hold itself to any arm, bridge or gateway by the "mutual attraction due to gravity"
However, once it moves out of those sections, it would be ejected from the galactic disc.
This is the real simple story about the spiral galaxy.
it is all about "mutual attraction due to gravity" between stars and gas without any need for dark matter.


Now, which theory is more realistic?
Is it the dark matter that can't explain the shape of the spiral galaxy (and many other questions)?
Or
Is it this simple understanding that gives an explanation for each section in the spiral arm and show why 280 Billion galaxies can hold their structure for almost indefinitely?

[Bored chemist]

The science community should be glad to understand that the dark matter is incorrect.

You should be glad to understand why you are incorrect.
But you refuse to.
Since part of your idea is impossible because of the laws of physics, the whole of your idea is impossible because of the laws of physics.
You really should rejoice in knowing that.
But you choose to ignore it.

[Bored chemist]

Now, which theory is more realistic?

The one that doesn't violate Kepler's law.

[Dave Lev (OP)]

The one that doesn't violate Kepler's law.

Dark matter imagination is the only one that violates Kepler's law.
We already know that there is no need for extra gravity at the Bar.
Please see the following confirmation for that from Kryptid:

Quote from: Dave Lev on Today at 20:12:19
Therefore it must be stable structure and there is no need for dark matter to explain the orbital velocity at the Bar.

I never said that dark matter was needed for the bar.

Thanks
So can we agree that the dark matter is not needed for the bar, but you think that it is needed for the spiral arms?

Therefore, as there is no need for dark matter in the bar, while based on the data it is fully there in the bar section (between 1KPC to 3KPC), then this dark matter clearly violates Kepler's law.
Please also be aware that this imagination can't give any explanation for the unique shape of spiral galaxy.
Therefore, it is irrelevant

You should be glad to understand why you are incorrect.
But you refuse to.

Sorry, you are the one that refuse to understand that the spiral galaxy doesn't need even one particle of dark matter.

Please read the following:

Any arm in the spiral galaxy (bar arm, ring arm & spiral arm) is based on "mutual attraction due to gravity" between the stars and gas in that arm.

I also like the following message from Kryptid about the arms:

Metastable is probably the better word.

So, the arms in the spiral galaxy is all about "mutual attraction due to gravity" between the stars and gas that are located in Metastable stage.
Once a section from the arm (with its hundreds or thousands stars) is ejected from the spiral arm, it get its stable stage by converting to globular cluster.
Therefore, all the globular clusters that we observe around the Milky Way are just small sections of arms that had been ejected from the spiral arms.
As long as the stars and gas are in the galaxy's arm - they are considered at their Metastable stage and form the arm structure.
Once, they are out of the galaxy's arm - they are considered at their stable stage and form the globular cluster structure

Since part of your idea is impossible because of the laws of physics, the whole of your idea is impossible because of the laws of physics.

There is no mistake in my idea as it fully meets all laws of physics especially the gravity law.
While the idea of existing of dark matter that we can't detect by any sort of detector and it still has so severe impact on gravity - this is the real idea that breaks the law of physics.

In any case, my idea gives perfect explanation for the full structure of the spiral galaxy.
It shows why the 280 Billions spiral galaxies in the visible universe can keep their structure for billions and trillions of years.
The dark matter by itself can't give any answer for the complex shape/structure of the spiral galaxy.
At the maximum, it gives an answer for the orbital velocity of stars at the spiral section. That's all.
Therefore, this idea which breaks the law of physics and can't help the spiral galaxy to form its unique shape with all its complex structure is just irrelevant
Spiral Galaxy is more than just orbital velocity.
Real theory must answer all the questions about spiral galaxy stracture (if possible - in one single explanation).
As the explanation about the "mutual attraction due to gravity" between the stars and gas in the galaxy' arm is the only one that offers full explanation for the complete structure of the spiral galaxy without any need for extra imagination - then it proves that it is the only real one!

[Bored chemist]

Please see the following confirmation for that from Kryptid:

I saw it.
It seems you did too.
You recognised the issue

but you think that it is needed for the spiral arms?

Yes.

And  then you ignored it.

[Dave Lev (OP)]

but you think that it is needed for the spiral arms?

Yes.

And  then you ignored it.

I didn't ignore it.
Even in the last reply I have stated:

The dark matter by itself can't give any answer for the complex shape/structure of the spiral galaxy.
At the maximum, it gives an answer for the orbital velocity of stars at the spiral section. That's all.
Therefore, this idea which breaks the law of physics and can't help the spiral galaxy to form its unique shape with all its complex structure is just irrelevant
Spiral Galaxy is more than just orbital velocity.

So, let's make it clear.
Do you confirm that the Dark matter has invented to "glue" the individual star in a fixed orbital motion (and radius) around the galaxy while its location in the arm was totally ignored?
Hence, the spiral arm was absolutely irrelevant for those scientists that have invented the dark matter imagination
without any second verification about the idea that the all those stars are located in spiral arms (including bridges and gateways between the arms)?
So, each star in the galaxy keeps its orbital radius around the galaxy by his own gravity force to the center of the galaxy.
Therefore, in order to help each star to accomplish his mission to keep its orbital radius while all move in a similar velocity, the dark matter had been invented.
Bravo!!!

Hence, based on this imagination our scientists have understood that stars must get in and out from the spiral arms. (as they have totally ignored the arms)
In order to solve this new problem our scientists have invented new idea that is called "density wave".
https://www.pa.uky.edu/~shlosman/anim/spiral_jam.gif
Based on this new imagination, due to the chance that there might be some traffic jam there is a possibility to get the spiral structure while each star in the galaxy keeps its orbital radius and its orbital velocity.
Second Bravo!!!

However, our scientists don't have any clue why there is a ring in the galaxy.
Why the based on the spiral arm is always connected to that ring from outside?
Why there is a bar?
 Why the bar is always in the inwards side of the ring?
And many other questions..

Do you really think that by offering dark matter to all of those 400 Billions of galaxies that are located in the visible universe, somehow 280 Billions would form their complex spiral structure,?
Let's assume that this imagination is correct and try to verify if it can work:
Take a sphere of 15KPC, set a SMBH at the center, set randomly 250 Billions of stars inside of that sphere (each one at different radius and at different orbital plane (as it is a Mega Bulge) and finally add the magic dark matter based on any sort of formula that you wish.
Now try to run it in your computer.
What is the chance to get any sort of disc shape from this random orbital motion of each star in the Mega Bulge (up to15KPC)?
If the dark matter works so well, why the Bulge (up to 1KPC) has a spherical shape instead of disc shape?
How many orbital cycles are needed for the Mega Bulge to be transformed to full spiral galaxy structure with its Bulge, Bar, Ring and spiral arm shape?
is it 50 cycles or 10^100....0 cycles?

Let's focus on the Milky Way:
Based on the current understanding, it takes the Sun 240MY to set one orbital galactic cycle while it keeps its radius of 8KPC.
Therefore, Even if the Sun was there from day one of the galaxy, at the maximum it could set 13By/240M = 54 cycles.
So, what is the chance for the Milky way to get its full spiral galaxy structure in just 54 galactic cycles of the sun?

On the other hand, let's assume that 54 cycles is perfectly OK.
A star that is located at 4KPC in the spiral arm would set one orbital cycle in 120MY
Hence, how long it should take the sun (or any other star) to get out from its spiral arm and how long it should take the spiral galaxy to break its structure?

So, how can you explain that for any three galaxies in the Universe, about two galaxies are spirals (remember the 70%)?
Do you think that all of those 280 Billions spiral galaxies are there just by good chance of traffic jam?

Sorry, the dark matter & the traffic jam can't represent any sort of science.
It is a pure imagination from people that have totally failed to understand how spiral galaxy really works.
Unfortunately you keep on with this approach.

[Bored chemist]

At the maximum, it gives an answer for the orbital velocity of stars at the spiral section. That's all.

So, you accept that, without it, Kepler's laws are broken.

[Bored chemist]

Hence, the spiral arm was absolutely irrelevant for those scientists that have invented the dark matter imagination

No
That's absurd.
The motion of the spiral arm was exactly what the dark matter was hypothesised to explain.

[Origin]

Therefore, in order to help each star to accomplish his mission to keep its orbital radius while all move in a similar velocity, the dark matter had been invented.
Bravo!!!

Your ignorance of astrophysics, which you demonstrate daily, means that your posts are little more than anti-science ranting.
Scientist's 'invented' dark matter to explain:
1.  Galactic rotation.
2.  The movement of galaxies in galactic clusters.
3.  The greater than expected gravitation lensing of galactic clusters.
4.  The distribution of the cosmic background microwave radiation.

[paul cotter]

The ongoing spread of "anti-science" is something that is seriously worrying, certainly to me.

[Halc]

So, you accept that, without it, Kepler's laws are broken.

FYI, there's a lot of references to Kepler's laws (the third one especially), yet those laws only apply to orbits of insignificant masses about one significant (effectively point) mass. So the laws are not violated either with or without dark matter since the laws are not applicable in the first place.
1) 'Orbits' about the galaxy are not elliptical, or even planar.
2) A line segment joining some star and center of the galaxy does not sweep out equal areas during equal intervals of time, although it's pretty close with any star that has little eccentricity to its path.
3) 'Orbit' periods do not follow the square-cube rule, with or without dark matter.

What is being violated without dark matter is basic Newtonian law. We have objects (our solar system say) that accelerate far more than can be accounted for by the sum of the forces applied by all the various baryonic masses in the galaxy. Thus there must either be more (a lot more) mass that isn't baryonic, or Newton's laws (the inverse square one concerning gravitational attraction) are wrong.

[puppypower]

The

"Astronomers led by researchers at the University of Arizona spotted the brilliant quasar about 13.03 billion light-years from Earth"
"This quasar, called J0313-1806, can be dated back to just 670 million years after the Big Bang (the universe at this time was a mere 5% of its current age), making it the most distant and earliest quasar ever found. This quasar also hosts a supermassive black hole that has a mass equal to 1.6 billion of our suns. "

One of the conceptual problems that is not addressed is connected to the continued expansion of the universe from the BB. If the signals from that quasar did indeed travel for 13.03 billion years, and the universe was/is still expanding all that time, the original signals should have red shifted out of what we expect from a quasar, after 13 billion years of constant red shift expansion of early energy that cannot regenerate with matter.

The only way you can maintain the original signal of a quasar, is if the universe is not really expanding in terms of space-time. This way only a doppler shift will appear, and then stay constant, forever.

How can light, given off by a quasar, traveling in an expanding universe for 13 billions of years, avoid all the extra 13 billion years of red shift, due to the continuing expanding universe? If space-time is expanding all energy wavelengths stretch out, to lower and lower and lower energy.

What someone should do is use the observed energy signal and back calculate 13 billion years of blue shift; needed to go back into time 13 billion years. This energy calculation would make the starting quasar much hotter and much more massive, like nothing we have anywhere near our galaxy.  it may open up new early universe quasar formation scenarios. 

[Dave Lev (OP)]

The motion of the spiral arm was exactly what the dark matter was hypothesised to explain.

Sorry, you have a severe mistake.
The dark matter doesn't care about the spiral arms, Ring and Bar
It is mainly about the galactic rotation of stars.
Please see the following replies:

Scientist's 'invented' dark matter to explain:
1.  Galactic rotation.
2.  The movement of galaxies in galactic clusters.
3.  The greater than expected gravitation lensing of galactic clusters.
4.  The distribution of the cosmic background microwave radiation.

What about the complex structure of spiral Galaxy?
Why our scientists totally ignore that somehow there are 280 Billions spiral that should be explained (while the dark matter doesn't give any answer for their complex structure)?

What is being violated without dark matter is basic Newtonian law. We have objects (our solar system say) that accelerate far more than can be accounted for by the sum of the forces applied by all the various baryonic masses in the galaxy. Thus there must either be more (a lot more) mass that isn't baryonic, or Newton's laws (the inverse square one concerning gravitational attraction) are wrong.

Your explanation is valid as long as we ignore the arms.
So, if you look at a single star (as our solar system) and try to accounted the sum of the forces applied on it by all the various baryonic masses in the galaxy then you are fully correct - 

there must either be more (a lot more) mass that isn't baryonic

However, in this case, you totally ignore the great impact of the spiral arm?
Why is it so difficult to understand that any star outside the Bulge doesn't hold itself to the center of the galaxy, but holds itself to the arms (spiral arm, ring arm & bar arm)?
We have full observation that proves it.
How many times do I have to offer you the same article?

I have just found an excellent article about the Bar:
https://scitechdaily.com/galactic-bar-paradox-a-mysterious-and-long-standing-cosmic-conundrum-resolved-in-cosmic-dance/
It is stated:
"The bar pulsations result from its regular encounters with the Galactic spiral arms, in what can be described as a “cosmic dance”. As the bar and spiral arm approach each other, their mutual attraction due to gravity makes the bar slow down and the spiral speed up. Once connected, the two structures move as one and the bar appears much longer and slower than it actually is. As the dancers split apart, the bar speeds up while the spiral slows back down."
It is specifically stated: "their mutual attraction due to gravity makes the bar slow down and the spiral speed up."
It is also stated: "Once connected, the two structures move as one"

So why do you all insist to ignore the key functionality of the spiral?
Don't you understand that it is all about: "mutual attraction due to gravity" between the ordinary matter..

the "mutual attraction due to gravity" between the ordinary matter (stars and gas) at the edge of the Bar to the ordinary matter in the base of the spiral arm can bond them together and "move as one".

Why do you refuse to understand that the solar system doesn't need to bond itself by gravity to the center of the galaxy, but bond itself to the spiral arm by its own gravity, while the spiral arm is bounded by its gravity to the ring arm?
Hence there is no need for extra gravity force to bond the solar system to the center of the galaxy.
As long as the solar is bonded to the spiral arm, it would go wherever the spiral arm goes
However, if our Sun, would dare to move away from its spiral arm, then there isn't enough baryonic gravity to hold it in its orbital motion and it would be ejected from the galactic disc as a rocket.

[Bored chemist]

1.  Galactic rotation.

That includes the rotation of the spiral arms of the galaxy.