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QuotePlease look at our moon.The Gravity force of the Sun/Moon is stronger by more than a twice with regards to the Earth/Moon.If the Moon had to chose its orbital path based on the sum of the force vectors acting upon it, it will had to orbit around the Sun instead around the Earth, however - this isn't the case. Your understanding of orbital mechanics needs a lot of work. The strongest force acting on the moon is from the sun, and that means that at all times, the moon accelerates towards the sun. That's the implication of what I've said above. I did not say the moon cannot orbit Earth. The moon has no choice or preference about this. It moves exactly as per forces as described by Newton.
Please look at our moon.The Gravity force of the Sun/Moon is stronger by more than a twice with regards to the Earth/Moon.If the Moon had to chose its orbital path based on the sum of the force vectors acting upon it, it will had to orbit around the Sun instead around the Earth, however - this isn't the case.
We have to ask"The sun attracts the moon with a force twice as large as the attraction of the earth on the moon. Why does the moon not revolve around the sun?"
Please look at the following article:https://www.quora.com/The-sun-attracts-the-moon-with-a-force-twice-as-large-as-the-attraction-of-the-earth-on-the-moon-Why-does-the-moon-not-revolve-around-the-sun
"Here the moon and earth form a system, which is like a Binary system . If two astrologers rotate around their center of gravity together, then it is called binary system"
The answer is: "Binary system"So, this binary system is a "local gravity force" that gives the moon/earth system the possibility to orbit around the Sun.
Hence, the noon is not their by itself, as the earth is not their by itself.
But it is clear that without setting a binary system with the Earth - Just based on pure gravity force - the moon will prefer to orbit around the Sun.It will never ever set a binary system with the earth if it was orbiting around the Sun.
Few words about binary-and-multi-star-systems:https://stardate.org/astro-guide/binary-and-multi-star-systems"A binary is a pair of stars that orbit each other. A multi-star system consists of three or more stars. The stars in a binary or a multi-star system all formed from a single cloud of gas and dust, so they are true “siblings.”"
The Earth & the Moon are real "siblings". This is a key element. I will explain later on why the current concept of how the Moon had been created is absolutely unrealistic:
"The giant-impact hypothesis, sometimes called the Big Splash, or the Theia Impact suggests that the Moon formed out of the debris left over from a collision between Earth and an astronomical body the size of Mars, approximately 4.5 billion years ago"I will also explain how the earth and the moon had been formed "from a single cloud of gas and dust, so they are true siblings". and why they set this binary system due to gravity force.
But in order to explain it, we must know how our galaxy really works.The spiral arm is a key element in our discussion.Therefore, understanding the gravity force between the objects in the arm is vital.So, the Earth/moon is a binary system which holds them both while they orbit around the Sun. In the same token, the arm is a multi-star-system.Each star in the galaxy has its own virtual host point.Together, those host points set that "multi-star-system" which holds all the neaby stars in the arm.
Sure, arms hold themselves together via gravity. That is pretty simple since force (towards galactic center) goes up at the outside edge of the arm, and force (towards galactic center) goes down on the inside edge.
If you agree with that, than this is all is needed to explain the spiral arm structure.
As I have stated, each star is connected in the arm by Newton gravity force. All the stars have a similar orbital speed. (More or less)
Therefore, for any time frame, they all cross the same distance.
In order to achieve it, as they drift outwards, they also drift backwards.That activity sets by definition the spiral shape of the arms.
Now, let's try to find what our scientists have to say about: "How Our Milky Way Galaxy Got Its Spiral Arms"
https://www.space.com/24642-spiral-galaxies-milky-way-shape-explained.htmlDated - February 12, 2014
"The researchers found that the universe was a very chaotic place in its infancy. The first galaxies were disks with massive, bright, star-forming clumps and little regular structure. To develop the nice spiral forms seen today, galaxies first had to settle down, or "cool," from the previous chaotic phase. This evolution took several billion years."First contradiction - "Massive disc galaxies" - If our universe was "very chaotic place in its infancy" how could it be that we have got immidiatly disk galaxies with massive, bright, star-forming clumps and little regular structure."Why those massive disc galaxies had been developed in the chaotic Universe? How long it should take to set the first massive disc galaxy in that unclear process? How could it be that all the billions spiral galaxies formed from this chaotic Universe?
Second contradiction - "Age" - We see spiral galaxies at the most far end of the Universe.The estimated age of many mature spiral galaxies is more than 13.2 Billion years.So, how could we see today very mature spiral galaxies at estimated age of only 0.6 billion years, if based on this article we need several billions (3.6 Min) and also with the assumption that we have got "Massive disc galaxies" almost immediately from the chaotic Universe?
Third contradiction – "Random process" - They don't show exactly how do we get this spiral arms from massive disc galaxy. They just say that "Gradually, the galaxies that were to become spirals lost most of their big clumps,.."This is a random activity by definition. They don't say why they lost the big clumps and how they really got their spiral arms based on Newton gravity.
Conclusions:I have set a simple explanation why 400 Billion spiral galaxies have got their spiral shape from day one based on Newton gravity force.
You can accept it or reject it.
The speed at which everything moves is unexplained by your assertions. You never address this issue.
Your link above seems to be fairly in line with similar graphs I've seen.
Than it goes down to about 190 Km/sec at 3KPC.
The ends of the bar are moving faster than anything else, just like the ends of the thrown spanner are moving faster than the rest of it.
I get that at about 0.5 KPC.
QuoteWhy they also give this information without any connection to the galaxy shape?It seems there is little connection. Objects at radius X move at the same speed regardless of being in an arm, near one side or the other, or between them. The arm might affect regular wobble in and out, but not the tangential speed around the galaxy.
Why they also give this information without any connection to the galaxy shape?
No, it means that not a lot of pop-science web sites focus on that part. I haven't tried much to actually see what the consensus is about how things move in that inner 3 kps, and how the bar keeps its shape. Such a thing is fairly common, hardly a weird anomaly of just our own galaxy.
The arms seem not to be continuous tubes of stellar material, but rather chunks arranged sort of like fallen dominoes...
Well I don't see it from that data.
The ring I think is way outside, like maybe 40 kps or something, a halo of gas not particularly dense enough to form luminous objects.
QuoteThe one which is closer to the Sun is called: Near 3KPC ArmThe one which is farther from the Sun is called: Far 3KPC ArmTogether they set the ring.No, they set the inner portions of a spiral.If you want to call it a ring, fine, but the two arms do not connect. Each spirals out into the two major arms. The image clearly shows this. I notice both arms get noticeably thicker at the point halfway around when the pass relatively close by the opposite end of the bar from which they appear anchored.
The one which is closer to the Sun is called: Near 3KPC ArmThe one which is farther from the Sun is called: Far 3KPC ArmTogether they set the ring.
As I said, I can consider that a ring if you wish, but I see a clear spiral thereGreat! Other people call it a ring. Let's go with that.
Let's start with the following question:What kind of gravity force that ring could generate?Let's assume that there is no SMBH at the center.Let's also assume that we set Billion of stars at a perfect ring of 3KPC and hold them ALL at their current position for very long time.(Please don't tell me what will happen to the ring after one minute. This is a theoretical question about stars ring)
What kind of gravity force we might find inside the ring?
Do you agree that all the stars together will set an equivalent gravity force on any object which is located inside that ring?
Therefore:1. If an object is located directly at the center - Do you agree that the impact of the gravity force from the stars in the ring at a distance of 3KPC in one side should cancel the impact of the stars in the other side of the ring? Therefore, the net gravity force on that object is - Zero?
2. If an object is located at 1.5KPC from the Center (Let's set it close to 12 (in clock) - The impact gravity force of the stars in 3 and 9 should cancel each other?
However, the distance to 12 is now 1.5 KPC while the distance to 6 is 4.5KPC.Therefore, do you agree that the net gravity force in the direction of 12 is quite strong?
3. If an object is located very close to 12 (let's say at 2.9 KPC). - The impact of the gravity force in 12 is almost maximal (as the distance is just 0.1KPC). However, the impact of 6 is minimal (as the distance is 5.9KPC). Remember that 3 cancel the impact of 9.
Therefore, do you agree that the impact of the ring gravity force is higher as the object is closer to the ring?
Without reading further, a hoop like that is in equilibrium and can orbit itself, with or without a central object. The mass within (not part of) the ring will contribute to higher speed of the ring, but a ring by itself will have some minimum speed. It isn't totally stable, but stable enough, just like our asteroid belt, which has a central mass. I can think of no example of a ring on its own.
You treat the ring and arms as solid objects, talking about loads being put on them and such. They're not. They're collections of detached objects which don't alter paths if loads are put on other parts. You can't alter the speed of the ring by putting a force on part of the ring. That works only if it is an object.
agree that the spiral seems to end at 3 kps, not spiraling all the way into the center. There are some galaxies that do that, but they're in the minority.
Quote from: HalcYou treat the ring and arms as solid objects, talking about loads being put on them and such. They're not. They're collections of detached objects which don't alter paths if loads are put on other parts. You can't alter the speed of the ring by putting a force on part of the ring. That works only if it is an object.I disagree with you,The ring is an object by itself as the Earth is an object by itself.The Earth is made by many different of Atoms and molecular that are all bonded by gravity force.In the same token, the Ring is made by many Stars and dust that are all bonded by gravity force.
We see clearly that the arms are connected exactly at the opposite sides of the ring.In some galaxies it is quite difficult to see the ring, but we see clearly that spiral arms are connected exactly at the opposite sides of the ring and directly to the bar.This connection between the Arm to the Bar is very important.
Please look at the following image:http://hubblesite.org/image/1636/news_release/2005-01Please see the ratio between the bar radius to the arm maximal radius:Do you agree that the ratio is about 1:3?
In the Milky Way the bar gets to 3 KPC while the spiral arms gets to 45 KPC.So the ratio in the Milky way (with a ring) is 1:15.
Do you agree that without a ring (or with minimal ring) there is a maximal load (or maximal spiral arm size/radius) that spiral galaxy can take?
Our scientists only try to explain the orbital velocity in the arm, but they ignore completely the Bar. How could it be that they don't see that the bar is directly connected to the arm?
3. How could it be that at the ring, the orbital velocity is at its minimal value (190Km/s)?
If you look at the Milky Way image in your first link of the prior post, the bar ratio seems to be about 1:5 or 1:6, and a similar ratio for that 'perfect spiral' galaxy you link.So the ratio is higher, but not a lot higher.
QuoteOur scientists only try to explain the orbital velocity in the arm, but they ignore completely the Bar. How could it be that they don't see that the bar is directly connected to the arm?Probably because it isn't.
So, we agree that with a ring the ratio between the bars radius to the maximal arm radius is higher.If so, why do we ignore the outcome of this evidence?
5. Based on this image, it is clear the bar is orbit in clock wise.
8. So do you agree that we see clearly a symmetrical view from both end sides of the Bar?
Don't you think that there is a meaning for what we see?
As you don't like to call this spot as a "connection" point, do you estimate that the bar can move faster/slower than the starting point of the main arms and one day it should be disconnect from the arm?
QuoteAs you don't like to call this spot as a "connection" point, do you estimate that the bar can move faster/slower than the starting point of the main arms and one day it should be disconnect from the arm?You would have images of galaxies then where that happens. No, the [main] arms always start at the bar ends, just like the wake always starts at the duck despite not being connected .
As the bar had been set due to "density wave", can we claim that it is an object?If the ring isn't an object than how could it be that the bar is an object?
If it isn't an object, how can we compare it to duck?
Astronomers believe that galaxies have spiral arms because galaxies rotate – or spin around a central axis – and because of something called “density waves.”
So, the bar is there due to "density wave", while the spiral arms is there due to the same idea of "density wave".Hence, how could it be that the bar has a totally different shape and structure from the spiral arm while they both had been created based on the same concept of density wave?
I don't understand the dynamics of the bar. It seems to not be a density wave itself like the arms are, but I could be wrong about that. They give a reference to a paper on the subject, but it is heavy reading.
There are some really good illustrations that show what they're talking about.Here's a gif showing how a wave forms moving at one speed when all the material moves at a different speed.https://imgur.com/gallery/dtb8WrDFollow any particular star and it doesn't stay with either arm.
:https://en.wikipedia.org/wiki/Wake#/media/File:Bodensee_at_Lindau_-_DSC06962.JPGThe duck wake appears completely stationary to a camera that is following the duck, and has that overlapping fallen-dominos signature, not just one clean wave that angles out. The material of the waves does not follow the wave/duck however. The water is moving in a completely different direction than is the wake. The wake appears to be a solid object connected to the duck, but it is not connected at all.