[Dave Lev (OP)]

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."

[Kryptid]

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.

[Dave Lev (OP)]

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.

[Dave Lev (OP)]

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?

[Kryptid]

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).

[Dave Lev (OP)]

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?

[Kryptid]

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.

[Dave Lev (OP)]

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?

[evan_au]

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).

[Kryptid]

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?

[Dave Lev (OP)]

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".

[Kryptid]

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.

[Dave Lev (OP)]

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?

[Origin]

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

[Kryptid]

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.

[Dave Lev (OP)]

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?

[Origin]

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.

[Dave Lev (OP)]

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?

[Origin]

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. 

[Dave Lev (OP)]

I don't understand your question.

I mean the impact due to dark matter.
Please read the updated questions