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Quote from: DavidPlease look at the following article:https://www.space.com/19915-milky-way-galaxy.html"Spiral arms are like traffic jams in that the gas and stars crowd together and move more slowly in the arms. As material passes through the dense spiral arms, it is compressed and this triggers more star formation," said Camargo.So, our scientists belive that stars don't stay at spiral Arms but they just move slower at the arms.Therefore, all the stars actually cross the arms while they orbit around the galaxy.The article didn't say that. It explains that the stuff moving through the arms is slowed by friction, and thus tends to more or less stay in the arms. That seems to be why there are arms and not a homogeneous fog without structure.Nothing in that article suggests that all stars do a certain thing.The article says that stars and gas are slowed (by friction) to a lower speed relative to the arm, not relative to the galaxy. The whole galaxy moves at about 217 km/sec at this radius, and things moving at a different speed tend to match the local speed due to collisions with the thick material.
Please look at the following article:https://www.space.com/19915-milky-way-galaxy.html"Spiral arms are like traffic jams in that the gas and stars crowd together and move more slowly in the arms. As material passes through the dense spiral arms, it is compressed and this triggers more star formation," said Camargo.So, our scientists belive that stars don't stay at spiral Arms but they just move slower at the arms.Therefore, all the stars actually cross the arms while they orbit around the galaxy.The article didn't say that. It explains that the stuff moving through the arms is slowed by friction, and thus tends to more or less stay in the arms. That seems to be why there are arms and not a homogeneous fog without structure.Nothing in that article suggests that all stars do a certain thing.
In any case, if stars stay at the Arms (all the time from day one), than why is it?Does it mean that they hold each other by gravity force?If so, that exactly the whole idea which I have presented.
Quote from: DaveIn any case, if stars stay at the Arms (all the time from day one), than why is it?Does it mean that they hold each other by gravity force?If so, that exactly the whole idea which I have presented.I never disagreed with that. Yes, gravity (and friction) seems to be what holds them together, just like those two effects are what hold a solar system together.
Quote from: HalcYes, gravity (and friction) seems to be what holds them together, just like those two effects are what hold a solar system together.So, you agree that the stars hold each other in the arm due to gravity (or friction if you like)
Yes, gravity (and friction) seems to be what holds them together, just like those two effects are what hold a solar system together.
Therefore, do you agree that in this case each star must obey to the local gravity force in the Arm?
It is similar to the Earth/sun gravity force.
The Earth doesn't care about the gravity forces on the Sun. It is just holds/orbits the Sun by gravity force and follows it where ever it goes.
So, as we do not set the calculation why the Earth orbits around the galaxy, we also shouldn't worry why the sun orbits around the galaxy.The Sun holds itself in the spiral arm.Where ever the spiral arms goes - the Sun goes.
So, we have to find why/how the spiral arm orbits the galaxy and not why the Sun orbits the galaxy.
Only if the Sun is disconnected from the arm, than we must look for dark matter.
As long as is connected in the arm due to gravity, we must look for answers about the armWe might find that Dark matter is needed for the Arm, but there is no need to find an explanation for the Sun - as long as it is connected to the arm by gravity.
An asteroid orbits around the Moon. Hence, the moon holds this asteroid by gravity.The moon orbits around the Earth. Therefore, the Earth holds the Moon which holds the Asteroid by gravity.So, we can continue at higher hierarchy.
Therefore, at this phase, we must find the answer for – "Why the Arm orbits around the galaxy (and not why the sun orbits around the galaxy)"?Do you agree with that?
You keep asking this. Each star's velocity and acceleration is determined by the sum of the force vectors acting upon it. This is all things, not just local ones.
The arm is not an object like the sun is to Earth. The arm is a smear of matter, all moving at different orbits about the galaxy. Some of it goes around in much less time than parts further out. It isn't one thing that the sun follows.
In the same token - as long as the Earth is connected to the Sun by gravity force, we do not need to find an explanation why the Earth orbits around the galaxy.
With minor edits, sure. We must ask why the local portion of the arm orbits around the galaxy at the speed it does. Not why it goes around, but why so fast? It accelerates at about 2e-10 m/sec˛ and the mass of the matter we see in the galaxy is not enough to explain that acceleration.We know why the arm orbits: Things just do when there is a mass to orbit, such as the material that makes up the inner portion (stuff closer than us) of the galaxy. But orbital speed is very much a function of the mass of that material, and there apparently isn't enough of it.
Quote from: HalcEach star's velocity and acceleration is determined by the sum of the force vectors acting upon it. This is all things, not just local ones.Yes and No.Yes - based on theoretically point of view.No - based on real evidences.
Each star's velocity and acceleration is determined by the sum of the force vectors acting upon it. This is all things, not just local ones.
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.
Our scientists claim that more than 100 Billion Sun mass is needed to be at the orbital center of the Sun (in the galaxy) in order to hold the Sun in its orbital path.If we try to calculate the Galaxy/Earth gravity force (based on that mass), we should find that it is much higher than Sun/Earth gravity force.
So, Based on a pure sum of the force vectors acting upon the earth, it had to ignore the Sun and start running around the galaxy. But again - this isn't the case.
Each star orbits around a local virtual host point.
Therefore, although we see that all the stars are moving in different directions, their host points are very stable with regards to each other.Hence, The Arm Is an ARM. It holds all the Virtual host points at the arm due to local gravity force.This is the key element of spiral arm.
If the arm can't hold the stars, than by definition the stars must cross the arm and get out of it.
You can't just say that the stars stay at the arm but the arm doesn't hold them by gravity.This is none realistic statement.
Sorry - this is incorrect. We can't take it for granted. We need to find an explanation why the Earth orbit around the Sun although its gravity force is lower than the Gravity force of the galaxy.
I will give you a tip - Gravity Works locally.
There is no need for dark matter in the galaxy to hold the Sun in the orbital path around the center.All we need is - Gravity works locally in the arm (and everywhere).
The answer is very simple - Gravity works locally. If you agree with that - you have got the answer!!! There is no need for dark matter in the galaxy to hold the Sun in the orbital path around the center. All we need is - Gravity works locally in the arm (and everywhere).
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.
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.
Quote from: HalcThe speed at which everything moves is unexplained by your assertions. You never address this issue.Yes, I can explain it.However, I need to see the real data.Please look at the "Observed rotation curve" in the following article?http://ircamera.as.arizona.edu/astr_250/Lectures/Lecture_22.htmObserved rotation curve:We see that at about 0.2 KPC the orbital velocity is maximal - 260 Km/sec
Than it goes down to about 190 Km/sec at 3KPC.From this point it goes up to 210 Km/sec at 4KPCand to 230 Km/sec at 7 KPC.Than it starts to go down again to 200 Km/sec at 10KPCGoes up to 235 Km/sec at 13 KPC and stay at that velocity at any further distance.Is this correct?
If so, how could it be that we don't see the real orbital velocity near the SMBH?
We know that the orbital velocity of the plasma is 0.3 c (speed of light)At the end of this article it is stated:"Consider a star whose proper motion has been measured to be equivalent to 1000 Km/sec and which lies only 0.01 pc from SgrA*.So, why we don't see the real velocity at the center?\Why it shows that the orbital velocity at the center is almost Zero?
Why they also give this information without any connection to the galaxy shape?
I would expect to see measured velocities per radius in the following segments:1. Accretion disc (What is the Min radius and maximal radius. What is the orbital velocity at each radius?
2. Bulge - Radius range and velocities
3. Bar - Radius range and velocities
4. Ring - Radius range and velocities
5. Disc/spiral arms - Radius range and velocities
6. From the end of the disc - Radius and velocities
Would you kindly direct me to the real measurements of orbital velocities Vs radius in the Milky Way? (From 0 - 20K Pc)I will give full explanation once I have the real data.
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.
So as you agree on this graph, let's set the correlation with the structure.In order to do so, please look at the following diagram of the Milky way structure:http://www1.ynao.ac.cn/~jinhuahe/know_base/astro_objects/galaxies/Milky-Way-Galaxy-files/logarithmic-spiral-pattern-before2001.JPGWe can see clearly that the radius of the ring is 3Kpc.
So, the orbital velocity at the ring is 190 Kpc.
That shows that at the end of the bar, the orbital velocity is minimal. That evidence contradicts your following message:Quote from: Halc on 03/01/2019 14:55:16 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.
So, the end of the bar has the minimal orbital velocity.This by itself must set a big red light. How could it be???
In any case, the spiral arms starts exactly at that ring (3KPC).We don't see the end of the arms but we can assume that it ends at about 15 KPC (at about 45K light year).Let's focus on the Bar and the bulge:As we move inwards from the ring the orbital velocity is increasing.It almost goes to 260 Km/s at 0.5KPC.However, as we get closer to the center from that radius, the orbital velocity gets down.At about 0.1 KPC the orbital velocity is almost Zero!!!
This is a very important segment in the galaxy.There is a meaning for that activity.Our scientists focus only on the orbital velocity of the stars in the arms, while they ignore completely other important segments..That shows that their knowledge in spiral galaxy is very poor.
I can explain each segment.However, do you agree by now that there is high correlation between the galaxy structure and the orbital velocity?
Do you agree that your following message is incorrect?Quote from: HalcIt 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.
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.
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.
Please look at the following image from NASA (which is identical to the one that you have offered)https://solarsystem.nasa.gov/resources/285/the-milky-way-galaxy/It shows clearly that at 3KPC there are two sides of the ring
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.
The end of the Bar is directly located just between those arms on each side.
How can you claim that:Quote from: HalcThe arms seem not to be continuous tubes of stellar material, but rather chunks arranged sort of like fallen dominoes...
The data is clear. It is time for you to agree with the evidences.There is a clear ring at 3KPC!!!This ring has a great impact on the activity of the galaxy.I will explain it later on.
But first - do you agree that :1. There is a ring at 3KPC?
2. The orbital velocity at that ring is minimal - 190 Km Sec?
3. The Bar ends exactly at that ring?
4.The arms starts to form exactly from that Ring?
Why do you disqualify even the clear evidences which me & you represent?Why are you so negative?
Would you kindly look again at the evidences and try to understand that spiral galaxy is not just spiral arms?Would you kindly try to be more cooperative and help us to highlight the real activity at spiral galaxy?
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.