Naked Science Forum
On the Lighter Side => New Theories => Topic started by: Dave Lev on 14/11/2022 02:55:48
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Do you confirm, that the arm that is connected between the galaxies is all about stars & gas that are bonded by gravity force?
https://www.nasa.gov/image-feature/goddard/2022/hubble-inspects-a-pair-of-space-oddities
"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."
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I'm highly suspicious that this thread is going to be about material which you have had previous threads locked over. So let's get straight to the point: what is your "new theory" here? Keep in mind that if you start making the following arguments, this thread will be locked as well:
(1) That dark matter doesn't exist and that anomalous galactic rotation curves are caused by the gravity of regular matter alone.
(2) That gravity can be used to create unlimited energy.
(3) That it's the natural tendency for objects in orbit to move away from the body that they are orbiting without energy input.
(4) Any other physics-defying proposals you've made before.
So take caution in how you proceed. I will go back and look at your previous threads to check if I have to.
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Dear Kryptid
We discuss about the mutual gravitational attraction of the two foreground galaxies that have set that Gravitational Arm between the galaxies.
Is there any possibility to get a simple answer to my question?
Do you confirm, that the arm that is connected between the galaxies is all about stars & gas that are bonded by gravity force?
Yes or no please.
If you don't want to answer this question, then just let me know.
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Please look again at this amazing photo from NASA:
https://www.nasa.gov/image-feature/goddard/2022/hubble-inspects-a-pair-of-space-oddities
We clearly see that each galaxy is a two arms spiral galaxy.
While those galaxies are bonded by one arm the other arm of each galaxy is pointing exactly to the other side of the connected arm.
It almost seems as a one long line from the left arm of the first galaxy all the away to the right arm of the other galaxy.
Can you please explain this unique stracture?
As it is quite difficult to you to accept the idea that those spiral arms are all about Gravitational Arms, would you kindly explain how the idea of density wave could set that kind of almost a perfect line from side to side?
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Yes, it's formed by gravitational attraction. Calling it a "bond" isn't appropriate, though. It's certainly not a stable situation, as the stars and dust would eventually settle in one galaxy or the other (or be thrown out by gravitational slingshoting).
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Yes, it's formed by gravitational attraction.
THANKS
So you fully confirm that one spiral arm which is connected to the other galaxy is due to gravitational attraction.
Therefore, I hope that you agree that this arm should be called "Gravitational Arm"
Do you also agree that in each galaxy there might be hundreds of billions of stars?
Please look again on the following photo:
https://www.nasa.gov/image-feature/goddard/2022/hubble-inspects-a-pair-of-space-oddities
Do you see the bright dots in the "Gravitational Arm" of the upper galaxy.
Don't you see that those dots seems as a direct line?
Each dot could represent several millions of stars or clusters.
So how can you explain that long lines of bright dots (clusters)?
Don't you agree that those clusters (with million stars in each cluster) are connected by gravity to each other?
Calling it a "bond" isn't appropriate,
How would you call that gravitational connections between the bright clusters of millions or billions stars?
What's wrong with gravity "bonding"?
Now. please look at the other side of each galaxy.
Don't you agree that second spiral arm over there is almost in a pure symmetrical location (and also structure) with regards to the other "Gravitational Arm" - in both galaxies?
This arm isn't connected to any other galaxy, therefore, let's call it a free spiral arm.
You claim that:
It's certainly not a stable situation, as the stars and dust would eventually settle in one galaxy or the other (or be thrown out by gravitational slingshoting).
So, why this free spiral arm forced itself to locate exactly in the opposite side of the "Gravitational Arm" in that lovely symmetrical structure - in BOTH galaxies?
Why all the billion stars and all the matter in the free spiral arm are not thrown out by gravitational slingshoting?
Do you confirm that also this free spiral arm is due to "gravitational attraction"?
However, gravitational attraction with what?
We can understand that one spiral arm is there due to "gravitational attraction" with the other galaxy.
However, how can we explain that gravitational attraction in the free spiral arm and why all the billions stras there do not use the idea of gravitational slingshoting and find their way outwards from the spiral arm & the galaxy?
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Don't you see that those dots seems as a direct line?
It looks more wavy or crooked to me than a straight line.
So how can you explain that long lines of bright dots (clusters)?
The stars and gas in one galaxy are falling towards the other due to gravity.
Don't you agree that those clusters (with million stars in each cluster) are connected by gravity to each other?
Everything with gravity is technically connected to everything else with gravity in some sense.
How would you call that gravitational connections between the bright clusters of millions or billions stars?
Falling.
What's wrong with gravity "bonding"?
The word "bond" implies that the objects are joined together. This tidal tail is more like a waterfall, where the stars and gas are essentially in free fall from one galaxy to the other.
So, why this free spiral arm forced itself to locate exactly in the opposite side of the "Gravitational Arm" in that lovely symmetrical structure - in BOTH galaxies?
It looks like the tidal tail is the joining together of two previously "free" spiral arms.
Why all the billion stars and all the matter in the free spiral arm are not thrown out by gravitational slingshoting?
However, how can we explain that gravitational attraction in the free spiral arm and why all the billions stras there do not use the idea of gravitational slingshoting and find their way outwards from the spiral arm & the galaxy?
Because there's no reason that they should be. Some would every now and then, but it would be an extremely long process.
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The stars and gas in one galaxy are falling towards the other due to gravity.
Can you please explain how that "falling" mechanism works?
Let's focus on two similar stars that are located at the different sides of the Gravitational Arm that is connected between the two galaxies (A & B).
The star that is closed to galaxy A - is called star 1, while the other star that is close to galaxy B - is called star 2.
Do you agree that the gravify force on star 1 due to galaxy A should be much stronger than Galaxy B?
In the same token the gravify force on star 2 due to galaxy B should be much stronger than Galaxy A?
So how could it be that star 1 would "fall" in the direction of galaxy B (with less gravity force), while star 2 would "fall" in the direction to galaxy A (with less gravity force)?
Is it feasible to fall in the direction of less gravity force?
As an example - would you agree that an object on Earth should fall upward to the moon due to gravity?
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would you agree that an object on Earth should fall upward to the moon due to gravity?
Yes it does - it is called a "tide".
- But the gravitational force of the Moon (1/80 the mass of the Earth, at a distance of almost 400,000km)
- Is much less than the gravitational force of the Earth (at a distance of 6,300km)
- So the ocean tide is pretty small (typically 1 or 2 meters around here)
- And there is an equivalent tidal force on the far side of the Earth
However, it looks like these two galaxies have similar mass, and may have almost "touched" (the edge of a galaxy is a rather fuzzy boundary). So the tide can easily stretch from one galaxy to the other, tearing stars from both galaxies, and leaving a "luminous bridge" or "tidal tail" between them (NASA's words).
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Can you please explain how that "falling" mechanism works?
Pick up a rock and drop it. It's the same principle.
The star that is closed to galaxy A - is called star 1, while the other star that is close to galaxy B - is called star 2.
Do you agree that the gravify force on star 1 due to galaxy A should be much stronger than Galaxy B?
In the same token the gravify force on star 2 due to galaxy B should be much stronger than Galaxy A?
Yes.
So how could it be that star 1 would "fall" in the direction of galaxy B (with less gravity force), while star 2 would "fall" in the direction to galaxy A (with less gravity force)?
What I suspect happened is that these two galaxies had a very close encounter in their past (as evan_au says). The gravitational interactions between the two ended up dragging stars and dust out of their respective galaxies and thus forming the tidal tail. The tail would then currently be in the process of breaking up and resettling back into those two galaxies (except for whatever stars and gas had been given enough energy in the process to escape galactic recapture).
Since you posted this in New Theories, I'm assuming you are trying to say you have some kind of new explanation for what's happening here. What is it?
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Yes it does - it is called a "tide".
- But the gravitational force of the Moon (1/80 the mass of the Earth, at a distance of almost 400,000km)
- Is much less than the gravitational force of the Earth (at a distance of 6,300km)
- So the ocean tide is pretty small (typically 1 or 2 meters around here)
- And there is an equivalent tidal force on the far side of the Earth
Tidal gravity force can band the surface of the Erath and lift it by 1 - 2 m if there is a ocean over there.
However, I hope that you agree that it can't take even one drop of water from Earth.
However, you have stated a supper important message:
And there is an equivalent tidal force on the far side of the Earth
So, when tidal gravity force lift the earth surface in the closed side, it also has a similar effect/impact on the other side.
Therefore, we discuss on a symmetrical impact or shape due to tidal gravity force!!!
I think that this understanding of symmetrical impact due to tidal (gravity force) is a key issue for our understanding about the gravity impact!
Now please look again on the Photo:
https://www.nasa.gov/image-feature/goddard/2022/hubble-inspects-a-pair-of-space-oddities
Don't you agree that the connected arm (or bridge) between the two galaxies is all about one of the spiral arms??
Do you also confirm that on the other side of the galaxy we clearly see the other spiral arm.
Hence - do you confirm that both galaxies are actually two arms spiral galaxies.
I think that your following explanation due to tidal gravity force: "there is an equivalent tidal (gravity) force on the far side of the Earth", can also explain why there is a second spiral arm in the far side in each galaxy (as there is also an equivalent gravity force on the far side of the galaxy).
Now, please look carefully on the upper galaxy.
Do you confirm that it is a clear Barred_spiral_galaxy?
https://en.wikipedia.org/wiki/Barred_spiral_galaxy
Do you also confirm that in any barred spiral galaxy, there are two arms that goes exactly from the other side of the bar?
Actually, even the Milky way is a Barred galaxy:
https://phys.org/news/2016-07-earth-milky.html
we clearly see that it has two main spiral arms that are growing directly from each side of the bar.
However, it seems to me that most of the barred galaxy has several spiral arms around them.
So, how could it be that in this photo from Nasa we see in the same image two galaxies with only two spiral arms that are connected together in one of their spiral arms?
I don't think that it is just a good chance.
Therefore, please let me know if you agree with my following explanation:
Let's assume that those two spiral galaxies were just normal Barred spiral galaxies with several spiral arms around them exactly as the Milky way structure.
Based on the following explanation:
tearing stars from both galaxies, and leaving a "luminous bridge" or "tidal tail" between them (NASA's words).
As those massive Spiral galaxies with similar size came closer to each other stars in the far away spiral arms had been ejected "tearing" from both galaxies, and leaving a "luminous bridge".
That bridge is just one of the two main spiral arms that we see in any barred spiral galaxy.
I hope that you confirm that this "luminous bridge" is all about two spiral arms that are conected by gravity force due to mutual gravitational attraction.
If so, you also need to agree that those spiral arms can't rotate any more - I call them Frozen arms.
Never the less, as one spiral arm in the galaxy had been frozen by gravity force to the other galaxy, its second spiral arm at the other side of the galaxy can't rotate anymore and therefore it also must be frozen and keep itself on the other side of the galaxy due to the symmetrical impact of gravity (or tidal).
However, the Internal bar has to continue its rotation as there is no force that could froze the orbital motion of the bar.
Therefore, while the Bar continue to rotate, its two arms can't rotate any more.
For me, that photo from NASA (with the two frozen spiral arms at the two sides in each galaxy) is a solid observation that those spiral arms are all about gravitational arms and not just a "luminous bridge".
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However, once one spiral arm had been frozen by gravity force to the other galaxy
It isn't. Gravity isn't freezing anything in place here. It's like saying something in free fall is frozen in place. It's not. This tidal tail is a temporary structure.
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However, once one spiral arm had been frozen by gravity force to the other galaxy
It isn't. Gravity isn't freezing anything in place here. It's like saying something in free fall is frozen in place. It's not. This tidal tail is a temporary structure.
Dear Kryptid
Do you see that "luminous bridge"?
Do you agree that this bridge is all about a connection between one of the spiral arms from each galaxy?
If so, how that bridge could rotate while the arms are connected to each other by gravity force?
In the same token, don't you agree that if the arms were not there due to gravity force (or tidal force) than the other free spiral arm has to continue its rotation.
However, as we clearly see that both free spiral arms are frozen exactly at the other size on each galaxy it proves that it is all about tidal force as explaind by Evan_au:
And there is an equivalent tidal force on the far side of the Earth
Don't you agree that otherwise, the other free spiral arm has to rotate with the rotation movement of the bar?
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THANKS
So you fully confirm that one spiral arm which is connected to the other galaxy is due to gravitational attraction.
Do you fully confirm that this simulation shows that using our current theories a stream of stars between interacting galaxies is not a surprise?
https://svs.gsfc.nasa.gov/10687 (https://svs.gsfc.nasa.gov/10687)
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If so, how that bridge could rotate while the arms are connected to each other by gravity force?
Because that bridge is going to break. Watch the video Origin posted. At 0:16, it looks a lot like that galaxy pair you posted. Then just watch the video from there to see what happens.
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Watch the video Origin posted.
It is stated that this simulation is "over a period spanning two billion years of evolution."
If we divide it by 1.4 minutes (84 sec) we understand that each second represents 24 M years.
At 0:16, it looks a lot like that galaxy pair you posted.
Yes, at 0:16 it looks similar – but it has some key problems as follow:
1. The real interaction stars at 0:12 (till that moment, each galaxy keeps its full structure). After 2 sec (at 0:14), which represents 48 MY we already got the two-spiral arm structure in both galaxies.
2. From 0:14 till almost 0:23 (9 sec that represents - 216 My), each one of those two arms spiral galaxy kept its two arms structure.
3. If we focus on the free arm of each galaxy, in this simulation it took it almost from 014 till 0:44 (30 sec = 720M years) to complete only one orbital cycle.
4. From 0:46 till almost the end 1:40 (54 sec which represents 1,296 M Year) we see a severe ejection of matter from the galaxies.
Do you have an idea which kind of theories they have used to form this simulation?
How could it be that all the matter in each massive galaxy with its several spiral arms and hundreds of billions of stars had been transformed in just two sec (48MY) to a two arms spiral galaxy (without any major ejection of matter), and than kept this structure for 216 MY?
How could it be that it starts the real ejection of matter only at 0:46 and kept the ejection for almost 1.3 BY?
How could it be that the free arm in each galaxy sets just one orbital cycle in 720MY?
Is it all realistic?
Please look again at the real photo:
https://www.nasa.gov/image-feature/goddard/2022/hubble-inspects-a-pair-of-space-oddities
We clearly observe that both galaxies are almost in a "direct line" from the free arm of the upper (and left) galaxy to the free arm of the lower (and right) galaxy
At 0:16 we clearly see that the free arm of the left galaxy is pointing downwards, while the free arm of the right galaxy has a long cycle structure.
Actually at any other point of time in the simulation, we didn't get that "direct line" which is the most important feature in the real photo.
Don't you agree that this unique feature is due to tidal force as explain by Evan_au
And there is an equivalent tidal force on the far side of the Earth
Could it be that they didn't take in their simulation the real impact of this tidal force?
Therefore, the image at 0:16 looks similar - but it is so totally different.
I want to send many thanks to Evan_au
He actually found the key solution for spiral structure enigma.
His message that "there is an equivalent tidal force on the far side of the Earth" can clearly explain the spiral arms and also the Bar structure:
Please look again at any MW Bar:
https://phys.org/news/2016-07-earth-milky.html
Don't you agree that it looks symmetrical?
Please remember that the bar is made out of stars that are not fully connected to each other side by side as sand, rocks and water on earth.
Therefore, the matter there is much more flexible than the matter on Earth.
Hence, on Earth the gravity force tides the ocean by two meter as explained by Evan_eu:
So the ocean tide is pretty small (typically 1 or 2 meters around here)
While in the center of our galaxy, the bar is tided by KPC.
Can we explain that Bar shape without using the tidal idea?
Therefore, we would never see a spiral galaxy with only one arm and never Half of the bar that starts from the center in one direction.
Hence, do you agree that Tidal force is a key ellement in the formation of spiral galaxy?
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Do you have an idea which kind of theories they have used to form this simulation?
Yes, the science community refers to this phenomena as gravity.
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Do you have an idea which kind of theories they have used to form this simulation?
Yes, the science community refers to this phenomena as gravity.
Gravity with what?
Do you confirm that based on our current understanding each star is connected by gravity to the center of its galaxy by the dark matter?
Hence, it is not about a gravity impact between the real matter (stars) in each galaxy, but between each star to the dark matter in the galaxy.
Therefore, do you agree that it is all about dark matter?
How do they know the real impact on the dark matter during this collision?
Why they assume that dark matter would move in the expected direction and density?
How gravity by itself between two massive spiral galaxies could restructure the billion stars in those complex spiral galaxies into a dual arm galaxy in just 48MY while each star is bonding to its galaxy by dark matter?
Why they assume that while stars are ejected outwards from the galaxies, the combined dark matter would move to the center of the galaxies?
We know that each galaxy should have a complex formula for its dark matter
Therefore, how do they know that after the chaos of the collision between those galaxies they would get a perfect new dark matter formula for the merged galaxy?
Is there any possibility to simulate so complex situation and movement of dark matter & real matter at the same time?
Did they also use the idea of the density wave?
With or without it, how they have calculated that the dual spiral arm structure can keep itself for so long time (720 MY - in this simulation) while there is no gravity bonding between the stars in each arm?
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How gravity by itself between two massive spiral galaxies could restructure the billion stars in those complex spiral galaxies into a dual arm galaxy and keep this structure for so long time?
I don't understand your question. What do you mean "keep this structure for so long time". How long do you think a stream of stars between 2 galaxies should last?
Did they also use the idea of the density wave?
I doubt it.
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I don't understand your question.
I mean the impact due to dark matter.
Please read the updated questions
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Do you have an idea which kind of theories they have used to form this simulation?
The theory of gravity, most importantly.
Is it all realistic?
Take a look at the video I posted. It compares a simulated galactic collision simulation with observations of real galactic collision. So yes, I'd say it is realistic.
Actually at any other point of time in the simulation, we didn't get that "direct line" which is the most important feature in the real photo.
It's a matter of degree. Not all galaxy collisions are going to look exactly the same. If you want one that looks more like that, take a look at this simulation:
The time between 0:31 to 0:34 has the galaxies connected by a straight line of gas and stars.
Could it be that they didn't take in their simulation the real impact of this tidal force?
Simulating gravity would automatically simulate tidal forces.
Hence, do you agree that Tidal force is a key ellement in the formation of spiral galaxy?
I thought we were talking about a galactic collision, not the formation of a galaxy (unless you are talking about the formation of a new, unified galaxy after the collision of two different galaxies has settled down).
Hence, it is not about a gravity impact between the real matter (stars) in each galaxy, but between each star to the dark matter in the galaxy.
It's both.
How do they know the real impact on the dark matter during this collision?
We know the distribution of dark matter in our galaxy because we've measured it via star velocities.
Why they assume that while stars are ejected outwards from the galaxies, the combined dark matter would move to the center of the galaxies?
Some of the dark matter would likely be ejected as well.
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I mean the impact due to dark matter
Then you need to ask that question I'm not the telepathy guy...
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in our current understanding each star is connected by gravity to the center of its galaxy by the dark matter?
Our star is connected to the supermassive black hole in the center of our galaxy by the mutual gravitation of the Sun and the supermassive black hole.
- The same goes for every other star in our galaxy
- The same goes for every star and every other star in our galaxy
- The same goes for every star and all the Dark Matter in our galaxy (whatever it is)
Unfortunately, when you get 3 or more objects interacting gravitationally, it is too hard to write down a general equation for their motion ("in closed form" is the jargon)
- So astronomers have to use simulations of the gravitational interactions between stars and dark matter when simulating one galaxy, or the interactions between colliding galaxies.
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Do you confirm that based on our current understanding each star is connected by gravity to the center of its galaxy by the dark matter?
Why do you do that? You start with "do you confirm" and then state some convoluted story that is partially correct and partially your made up stuff with just plain wrong concepts sprinkled in.
So the simple answer to your question is no. The longer answer is; part yes, part kind of and part no.
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in our current understanding each star is connected by gravity to the center of its galaxy by the dark matter?
Our star is connected to the supermassive black hole in the center of our galaxy by the mutual gravitation of the Sun and the supermassive black hole
No!
You have a severe mistake.
In the following article it is stated:
https://www.e-education.psu.edu/astro801/book/export/html/1863
"If you take the semi-major axis of the Sun's orbit to be 8 kiloparsecs and the orbital period to be 250 million years, you can determine that the Milky Way's mass interior to the Sun's orbit is approximately 10^11 solar masses, or 100 billion times the mass of the Sun."
The SMBH mass is only 4*10^6 solar masses.
Therefore, it is clear that Our SUN is NOT connected to the supermassive black hole in the center of our galaxy by the mutual gravitation of the Sun and the supermassive black hole as the SMBH has not enough mass to hold the Sun by gravity.
Therefore, our scientists claim that there is a need for dark matter.
Please let me know if I understand correctly the current main stream explanation:
The Sun motion is affected by two kinds of gravity forces at the same time.
1. The gravity due to dark matter that holds it in its orbital motion around the galactic center.
However, the dark matter can't hold the Sun in the galactic disc by itself. There is a need for one more gravity force.
2. The Gravity due to the galactic disc that holds it in the disc. Therefore, based on the main stream the Sun is bobbling around the disc while it orbits around the galactic center
Please look again at the following video at 0:12
https://svs.gsfc.nasa.gov/10687
We clearly see that the galactic disc is lifted due to the collision.
Once you lift the disc you actually destroy the second gravity force that keeps the stars on the disc.
Hence, there is no way to keep the disc structure of the galaxy.
At the best scenario, you would get a spherical galaxy.
Do you agree with that?
If you want one that looks more like that, take a look at this simulation:
The time between 0:31 to 0:34 has the galaxies connected by a straight line of gas and stars.
Yes, this one looks better, however, there are still few issues.
Let me just focus on the following two issue:
1.In the simulation we see that those two massive galaxies collide which each other while their galactic disc is fully aligned with each other. What is the chance for that?
2. Please focus on the arm that is connected between the galaxies.
We see that at 0:31 there is a significant mass cloud around it.
At 0:35 that mass cloud is already absorbed in the arm and makes it thicker.
The arm keeps itself to almost 0:51. However, it gets more concentrated over time
Therefore, don't you agree that this arm is all about stars that are connected/bonded to each other by gravity.
https://www.nasa.gov/image-feature/goddard/2022/hubble-inspects-a-pair-of-space-oddities
Hence, why do you refuse to accept the simple idea that the bright line that we see in Nasa Photo is all about stars (or cluster of stars) that are connected to each other by gravity?
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1.In the simulation we see that those two massive galaxies collide which each other while their galactic disc is fully aligned with each other. What is the chance for that?
There are an awful lot of galaxies in the Universe. You'd expect collisions like that (or close to that) to happen once in a while. Perhaps the galaxy pair you have been talking about this whole time is an example of exactly that.
Therefore, don't you agree that this arm is all about stars that are connected/bonded to each other by gravity.
Gravity most certainly is an important factor in the shape of the arm.
Hence, why do you refuse to accept the simple idea that the bright line that we see in Nasa Photo is all about stars (or cluster of stars) that are connected to each other by gravity?
I'm not refusing it. I acknowledge that gravity plays an important role here. To be honest, I still don't really get what your new theory is and how it differs from what we already know about physics.
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Gravity most certainly is an important factor in the shape of the arm.
Therefore, don't you agree that this arm is all about stars that are connected/bonded to each other by gravity.
Gravity most certainly is an important factor in the shape of the arm.
Hence, why do you refuse to accept the simple idea that the bright line that we see in Nasa Photo is all about stars (or cluster of stars) that are connected to each other by gravity?
I'm not refusing it. I acknowledge that gravity plays an important role here.
Many Thanks!!!
I really appreciate that you are willing to accept the idea that the arm which is connected between the two galaxies is all about Gravitational arm where stars and gas clouds are connected to each other by gravity.
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I really appreciate that you are willing to accept the idea that the arm which is connected between the two galaxies is all about Gravitational arm where stars and gas clouds are connected to each other by gravity.
I guess that depends on what you mean when you say "all about".
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I really appreciate that you are willing to accept the idea that the arm which is connected between the two galaxies is all about Gravitational arm where stars and gas clouds are connected to each other by gravity.
I guess that depends on what you mean when you say "all about".
I mean that each star in that gravitational arm bridge holds itself by gravity force to the other stars in the arm
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I mean that each star in that gravitational arm bridge holds itself by gravity force to the other stars in the arm
In a sense... but it's not like some sturdy structure like the steel beams that hold a building up. The distances between those stars are constantly changing. This arm is dynamic, unstable, and will eventually lose its current form.
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I mean that each star in that gravitational arm bridge holds itself by gravity force to the other stars in the arm
In a sense... but it's not like some sturdy structure like the steel beams that hold a building up. The distances between those stars are constantly changing. This arm is dynamic, unstable, and will eventually lose its current form.
Well, this arm is dynamic and stable or unstable as any orbital system that holds itself by gravity.
I fully agree that eventually it should lose its current form as expected from any orbital system.
The life time of a star in that arm is not relevant.
Sooner or later all the stars would be ejected from the arm (as a single star or as a cluster of stars)
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So what is it about contemporary science that you are disputing here? I assume you put this into "New Theories" for a reason.
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So what is it about contemporary science that you are disputing here? I assume you put this into "New Theories" for a reason.
I'm slightly curious also. His idea that gravity holds galaxies together doesn't seem like a new theory.
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Do you confirm that based on our current understanding each star is connected by gravity to the center of its galaxy by the dark matter?
The word 'connected' implies a physical EM connection like bars and strings and such, stuff of which objects of varying degree of rigidity are made. Stars are not connected in this way. They instead interact via gravity. All matter attracts all other matter as described by F=GMm/r². That's it.
The visible structure of a galaxy is due to more than just gravity since without the other forces there'd be nothing to see at all, an there'd be perhaps a gathering of mass but no stars, arms, black holes, or anything. All those things require more than just gravity to form. No, they're not 'connected'. There's effectively empty space between the parts.
As for the 2nd part of your statement, there's nothing in F=GMm/r² that distinguishes dark matter from baryonic matter. There's not a separate formula for dark matter. It's the same either way.
Why they assume that dark matter would move in the expected direction and density?
Who is 'they'? Nobody is assuming this. Nobody sees the dark matter. It isn't in your picture. The dark matter does the same as the regular matter, except it doesn't interact via the other forces. The evidence of EM interaction is very obvious in some of the simulations, especially the super-symmetric one.
Please let me know if I understand correctly the current main stream explanation:
Dave, if you actually did understand something, I don't think you could bring yourself to display that understanding. It's not what you do.
The Sun motion is affected by two kinds of gravity forces at the same time.
Wrong. There's only one kind of gravity. Newtonian mechanics works just fine for a galaxy collision, and F=Mm/r² describes it exactly for every kind of matter.
The gravity due to dark matter that holds it in its orbital motion around the galactic center.
Orbital motion is a term usually reserved for simple 2-body systems in a Keplerian relationship. The path of no object around the galaxy is really an orbit. It isn't elliptical. It happens to sort of look like a circle drawn by somebody with Parkinson's disease, but it's pushing it to call it an orbit since there's no object being orbited.
There's nothing special about the galactic center. There's no special 'connection' to it. There's nothing particularly big there. We're attracted to all matter everywhere (not just in our galaxy), and F=Mm/r² perfectly governs our path, plus whatever other forces are involved such as meteors hitting the Earth which definitely divert it from the path gravity would otherwise have taken it.
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Do you confirm that based on our current understanding each star is connected by gravity to the center of its galaxy by the dark matter?
The word 'connected' implies a physical EM connection like bars and strings and such, stuff of which objects of varying degree of rigidity are made. Stars are not connected in this way. They instead interact via gravity. All matter attracts all other matter as described by F=GMm/r². That's it.
Dear Halc
Thanks for your excellent explanation.
Yes, I fully agree that: "All matter attracts all other matter as described by F=GMm/r²" and from now on I should call it: "interact" (or Interaction) via gravity instead of connect (or connection) via gravity.
You discuss about the "Bar":
The word 'connected' implies a physical EM connection like bars and strings and such
There is a bar in the MY galaxy.
We can clearly see this BAR at the center of our galaxy:
https://phys.org/news/2016-07-earth-milky.html
Do you confirm that this bar is there due to gravity interaction?
However, interaction with what???
If it was just a gravity interaction between the stars in the bar it was expected to get a spherical shape as a nice cluster of stars.
Evan _au offered an excellent explanation for tidal force that could form a Bar:
would you agree that an object on Earth should fall upward to the moon due to gravity?
Yes, it does - it is called a "tide".
- But the gravitational force of the Moon (1/80 the mass of the Earth, at a distance of almost 400,000km)
- Is much less than the gravitational force of the Earth (at a distance of 6,300km)
- So the ocean tide is pretty small (typically 1 or 2 meters around here)
- And there is an equivalent tidal force on the far side of the Earth
Please look again at the following image:
https://phys.org/news/2016-07-earth-milky.html
We clearly see that the bar has also gravity interaction with the two main spiral arms:
Preseus & Scutum-Centaurus
Therefore,
Do you agree that tidal gravity interaction between the stars/matter in the bar to the stars/matter in the two main spiral arms have set the bar shape (similar to the tidal impact between the earth/moon)?
Now let's go back to the simulation:
https://svs.gsfc.nasa.gov/10687
Please watch it at 0:16
Watch the video Origin posted. At 0:16, it looks a lot like that galaxy pair you posted. Then just watch the video from there to see what happens.
We clearly see the gravitational bridge arm and we also see the free arm that is located at the far side of each galaxy.
Based on my calculation, the "free arm" keeps its structure for almost 720 M year.
3. If we focus on the free arm of each galaxy, in this simulation it took it almost from 014 till 0:44 (30 sec = 720M years) to complete only one orbital cycle.
Without gravity interaction between all the stars in this free arm, how could it keep its structure for so long time?
Do you trust this simulation?
"The scientific theoretical model and the computational data output were developed by Drs. Brant Robertson and Lars Hernquist. AVL rendered more than 80 gigabytes of this data using in-house rendering software and Virtual Director for camera choreography."
Do you trust this work by Drs. Brant Robertson and Lars Hernquist?
If so, don't you agree that this "free" arm (exactly on the other side of the "gravitational arm bridge") is also there due to Gravity/tidal interaction?
Hence, can we also call it "gravitational arm"?
If you agree with the above, why can't we consider the two main spiral arms in the MY galaxy as gravitational arms?
Please look at the following image:
https://cdn.britannica.com/40/167240-050-FEAB05E2.jpg
We see that those two main arms go all around the galaxy (more or less).
Please remember - 70% of the galaxies in the universe are spirals.
What kind of force can keep spiral arms in their spiral structure for so long time except of gravity force?
Please also see the image of the galaxy from the side.
Do you confirm that the spiral arms get narrower as they are located further away from the center?
At the base of the arm (3KPC) - it is 3000LY, while at the edge of the arm (12- 15KPC) - it is 400LY.
What kind of force can do it except of gravity force?
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it was expected to get a spherical shape
By whom?
What kind of force can keep spiral arms in their spiral structure for so long time except of gravity force?
I'm not aware of any astrophysicists who claimed that it wasn't gravity that held the arms together.
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I'm not aware of any astrophysicists who claimed that it wasn't gravity that held the arms together.
Wow!
So do you confirm that each star in the gravitational spiral arm is interacted with the other stars in the arm by gravity force and goes together wherever the arm goes?
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So do you confirm that each star in the spiral arm is interacted with the other stars in the arm by gravity force and goes together wherever the arm goes?
Only to an extent. If you watch the simulation, those stars don't form an arm indefinitely, so those stars definitely aren't staying together long-term.
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So do you confirm that each star in the spiral arm is interacted with the other stars in the arm by gravity force and goes together wherever the arm goes?
Only to an extent. If you watch the simulation, those stars don't form an arm indefinitely, so those stars definitely aren't staying together long-term.
Yes, I fully agree.
Gravity interaction is limited in time duration.
It could be one million years or one billion years.
However, eventually, all the stars in the arm would be ejected outwards.
That is very clear.
Hence, as long as the star is interacted by gravity to the arm, it would go with the arm wherever it goes.
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Hence, as long as the star is interacted by gravity to the arm, it would go with the arm wherever it goes.
Only to an extent.
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Hence, as long as the star is interacted by gravity to the arm, it would go with the arm wherever it goes.
Only to an extent.
Agree!
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Dear Kryptid
Let's try to understand the impact of that statement:
"Hence, as long as the star is interacted by gravity to the arm, it would go with the arm wherever it goes."
Do you agree with the following:
1. The Orion arm is a gravitational arm.
2. The Sun is interacted by gravity to the Orion and it would go with this arm wherever it goes.
To get better understanding about this issue let me use the Sun/Earth/Moon system:
The Moon is interacted by gravity to the Earth and it would go with it wherever the earth goes.
The Earth (or actually the Com of the Earth/moon) is interacted by gravity to the sun and it would go with it wherever the sun goes.
Therefore, the moon and the earth are not directly interacted by the center of the galaxy
Their "Gravitational job" is to keep themselves under the gravity interaction with the Sun.
In the same token, the Sun is not directly interacted with the center of the galaxy.
Its "gravitational job" is to keep itself under the gravity interaction with the Orion arm and as the Orion arm orbits around the galaxy, the sun will follow.
If you agree with the above message, why do we insist that the Sun should be under a direct gravity interaction with the center of the galaxy?
Could it be that the assumption that the sun should interact directly by gravity to the center of the galaxy leads us to the wrong understanding that the SMBH mass isn't enough and there is a need for dark matter?
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You are wandering dangerously close to things you have discussed in closed threads. Compare this statement of yours...
"Hence, as long as the star is interacted by gravity to the arm, it would go with the arm wherever it goes."
,,,with this previous statement of yours in a closed thread...
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.
And compare this...
To get better understanding about this issue let me use the Sun/Earth/Moon system:
The Moon is interacted by gravity to the Earth and it would go with it wherever the earth goes.
The Earth (or actually the Com of the Earth/moon) is interacted by gravity to the sun and it would go with it wherever the sun goes.
Therefore, the moon and the earth are not directly interacted by the center of the galaxy
Their "Gravitational job" is to keep themselves under the gravity interaction with the Sun.
In the same token, the Sun is not directly interacted with the center of the galaxy.
Its "gravitational job" is to keep itself under the gravity interaction with the Orion arm and as the Orion arm orbits around the galaxy, the sun will follow.
...with this...
We think that the Moon orbits around the Earth, but in reality it orbits around a common center of mass with the Earth. Let's call this point as ComE.
This ComE orbits around a common center of mass with the Sun. Let's call this point as ComS
Therefore, we already see two stages of gravity bonding.
Hence, while the moon is bonded locally with ComE and this comE is bonded with ComS, then although the moon orbits locally around a common center of mass, it goes wherever the Sun goes.
In the same token, we can claim that each star in bonded locally to a center of mass that is integrated in the arm and it goes wherever the arm goes.
...and you're using it all as an argument that there is no need for dark matter (which is exactly what you did in a previous thread). If you keep going with this argument, this thread will be closed as that would make it an attempt to bypass a thread lock.
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Dear Kryptid
You are the one that fully confirmed that spiral arm is gravitational arm:
Quote from: Dave Lev on Yesterday at 05:32:39
What kind of force can keep spiral arms in their spiral structure for so long time except of gravity force?
I'm not aware of any astrophysicists who claimed that it wasn't gravity that held the arms together.
So, you fully agree that gravity held the arms together.
You also confirmed that as long as the star is interacted by gravity to the arm, it would go with the arm wherever it goes:
Hence, as long as the star is interacted by gravity to the arm, it would go with the arm wherever it goes.
Only to an extent.
This breakthrough understanding is based on an important work/simulation that have done by Drs. Brant Robertson and Lars Hernquist:
"The scientific theoretical model and the computational data output were developed by Drs. Brant Robertson and Lars Hernquist. AVL rendered more than 80 gigabytes of this data using in-house rendering software and Virtual Director for camera choreography."
Do you trust this work by Drs. Brant Robertson and Lars Hernquist?
Therefore, do you claim now that all the above is incorrect?
If it is correct, why do you refuse to agree that:
1. The Orion arm is a gravitational arm.
2. The Sun is interacted by gravity to the Orion and it would go with this arm wherever it goes.
Why do you insist that there is a need for dark matter gravity interaction with Sun, while it is 100% clear to all of us that the sun is interacted by gravity to the spiral arm?
Would you kindly explain what is the mission of this forum?
Do you need to protect the main stream concept even if you clearly understand that there is a fatal error in their theory?
You know, 500 Years ago the main stream concept was that the Earth is the center of the Universe.
Anyone that dare to claim differently could lose his life.
Now nobody is going to lose his life if he proves that there is a fatal error in the current mainstream.
However, his tread would be closed.
Therefore, I want to thank you all (including Halc & Evan_au) for your excellent support that helped me to understand how gravitational spiral arm really works.
Now you are more than welcome to close the tread in order to protect the mainstream concept from a contradiction that had been proved as a real science.
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So, you fully agree that gravity held the arms together.
And the gravitational contribution from dark matter is an important part of that.
You also confirmed that as long as the star is interacted by gravity to the arm, it would go with the arm wherever it goes:
You say that despite quoting me where I said, "Only to an extent". The gravitational attraction between the stars alone isn't enough.
Therefore, do you claim now that all the above is incorrect?
No, what I claim is incorrect is your misrepresentation of it.
If it is correct, why do you refuse to agree that:
1. The Orion arm is a gravitational arm.
2. The Sun is interacted by gravity to the Orion and it would go with this arm wherever it goes.
The Sun doesn't orbit the arm, it orbits the center of the galaxy.
Why do you insist that there is a need for dark matter gravity interaction with Sun, while it is 100% clear to all of us that the sun is interacted by gravity to the spiral arm?
Who is "all of us"? You're the only one I've seen here insisting, incorrectly, that the Sun's attraction to the spiral arm is enough to eliminate the need for dark matter.
Would you kindly explain what is the mission of this forum?
To discuss science, which is one reason why threads get closed when the original poster insists on ignoring scientific evidence despite being corrected over and over again to no avail.
Do you need to protect the main stream concept even if you clearly understand that there is a fatal error in their theory?
Your misunderstandings are not evidence of a "fatal error" in mainstream science.
You know, 500 Years ago the main stream concept was that the Earth is the center of the Universe.
Anyone that dare to claim differently could lose his life.
Now nobody is going to lose his life if he proves that there is a fatal error in the current mainstream.
However, his tread would be closed.
That's a false analogy. One scientific idea being wrong in the past is not evidence that the concept of dark matter is wrong in the present.
Therefore, I want to thank you all (including Halc & Evan_au) for your excellent support that helped me to understand how gravitational spiral arm really works.
You don't. If you did, you wouldn't be insisting on this idea that defies the law of gravity.
Now you are more than welcome to close the tread in order to protect the mainstream concept from a contradiction that had been proved as a real science.
You have not demonstrated a contradiction in a mainstream concept, let alone proven it "as a real science".
Since you have pretty much owned up to trying to bypass a thread lock, then this thread will be locked as well.
Please, don't try it again.