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3. Bulge (0 - 1KPC) - Why in the bulge each star orbits at different direction and orbital plane?Why the Dark matter can't force the stars in the bulge to orbit in a disc?4. Bar (1KPC to 3KPC) - How the dark matter could form the unique structure of the Bar?
Today I heard some projections on what might happen when the Milky Way Galaxy merges with Andromeda to form "Milkomeda".They suggested that the result will be an elliptical galaxy, with stars taking many random paths.- ie a bulge larger than our current galaxy- and no bar- I am sure that the university/supercomputer-level simulations would have taken into account some hypothetical distribution of Dark Matter in the original galaxies and the merged galaxy
Maybe it is time to go down to the bar and have a glass of dark matter.
http://pubs.sciepub.com/ijp/7/3/2/index.html#Figure4"New Formulas and Mechanism for the Spiral Arm Formation of Galaxies"It is stated:"This model is the first attempt to think the spiral arm formation with the hydrogen originated from inside of the galactic center to outside. The proposed mechanism of the hydrogen production seems highly speculative, but the result of the simulations is very satisfactory,
I'm a chemist.Why do you imagine I know or care how galaxies work?
It is stated that: "the result of the simulations is very satisfactory"
Why do we continue to hold the dark matter imagination?
Why can't we accept the simple observation and the mathematical simulation validation that the Bar is used as a funnel to drift stars from the Bulge directly to the spiral arms?
Why do we insist to believe in something that we can't see feel or smell?
then why do you waste our time?
Because the simulation being correct wouldn't eliminate the need for dark matter. The anomalous galactic rotation curve still needs to be explained.
http://pubs.sciepub.com/ijp/7/3/2/figure/4The yellow line represents stars as they migrate outwards from the Bulge directly into the spiral arms.We see that the Bar looks as a propeller of an airplane.Let's assume that a star in a radius of 1KPC (R1) orbits at velocity V1 and try to verify the velocity of a star at different radius at this Bar (propeller)It is clear that:V = V1 (R / R1).If R = R2 = 2KPCV2 (at 2KPC) = 2 V1 (at 1KPC)V3 (at 3KPC) = 3 V1That linear increase in the calculated orbital velocity is fully correlated with the orbital velocity observations at the Bar section (Below 3KPC):https://www.astronomy.ohio-state.edu/thompson.1847/1101/RotCurve2.gifIf you agree with that we can move on to the spiral arms.
Is it clear?
Orbital velocity is determined by gravity.
The bar isn't some kind of magical propulsion system that lets stars violate Kepler's third law.
https://scitechdaily.com/galactic-bar-paradox-a-mysterious-and-long-standing-cosmic-conundrum-resolved-in-cosmic-dance/It is stated:"The bar pulsations result from its regular encounters with the Galactic spiral arms, in what can be described as a “cosmic dance”. As the bar and spiral arm approach each other, their mutual attraction due to gravity makes the bar slow down and the spiral speed up.Once connected, the two structures move as one and the bar appears much longer and slower than it actually is. As the dancers split apart, the bar speeds up while the spiral slows back down."It is specifically stated: "their mutual attraction due to gravity makes the bar slow down and the spiral speed up."It is also stated: "Once connected, the two structures move as one"
There is no violation of any physical law by the Bar (including the Kepler's third law).
It is specifically stated: "their mutual attraction due to gravity makes the bar slow down and the spiral speed up."
Hence the same gravity force that holds the stars in the bar arm and in the spiral arm as one connected temporary structure, also keeps each arm as a temporary structure.
The bar contains stars too. If the bar is slowing down, then the stars in the bar are also slowing down. So you have some stars speeding up and others slowing down. So overall, there is no average gain in velocity. If there is no average gain in velocity, then the anomalous galactic rotation curve remains unresolved.
QuoteQuote from: Dave Lev on Today at 09:09:17Hence the same gravity force that holds the stars in the bar arm and in the spiral arm as one connected temporary structure, also keeps each arm as a temporary structure."Temporary" being the key word here. What do you think happens when they are no longer one structure?
Quote from: Dave Lev on Today at 09:09:17Hence the same gravity force that holds the stars in the bar arm and in the spiral arm as one connected temporary structure, also keeps each arm as a temporary structure.
Even if it was true that they somehow sped up and retained that increased orbital speed indefinitely, then they should no longer be able to maintain an orbit around the Milky Way galaxy because they are going too quickly to be retained by the Milky Way's gravity.
That was the whole problem from the beginning.
The stars in the outer regions of the galaxy are orbiting too fast for the amount of gravity that the Milky Way should be producing if there was only normal matter present.
The fact that the galaxy has kept these super-fast stars demonstrates the need for extra gravity that is caused by something we can't see: i.e. dark matter.
Don't you agree that the dark matter idea can't offer a solution for the galactic rotation curve in the Bar segment?
If you think that the gravity is not good enough for the Bar, then how the bar really works based on your understanding?
If you try to break down the temporary structure of the spiral arm in the galactic disc, then all the stars in that arm would be kicked out from the galactic disc.
Nothing would help. Not even the dark matter imagination.
Again, do you mean that there is a problem in the bar or in the galactic disc?
But so far you have no real solution for the Bar rotation curve problem?
As the stars are connected to the spiral arm, then their orbital velocity is dictated by the orbital velocity of the arm itself.
The dark matter idea CAN'T explain this phenomenon!!!
Why do we prefer the dark matter idea that can only solve 25% of the problems while the gravity of the spiral arms can solve 100% of the problems?
Please be aware that at some point those far end stars in the spiral arms must be disconnected from the arm.The dark matter idea can't also give an answer for that
Therefore, the only way for a star to keep itself in the galactic disc is by holding the spiral arm.
QuoteQuote from: Dave Lev on Yesterday at 18:55:01Why do we prefer the dark matter idea that can only solve 25% of the problems while the gravity of the spiral arms can solve 100% of the problems?Where did you get those numbers from?
Quote from: Dave Lev on Yesterday at 18:55:01Why do we prefer the dark matter idea that can only solve 25% of the problems while the gravity of the spiral arms can solve 100% of the problems?
It is much less than 25%.
I hope that we all agree that our scientists don't have a clue what is it and how it had been created and why it is there exactly at the density that they wish.
However, please specify the dark matter density formula that is invented for the Milky way.
2. Galactic Disc -A. How this dark matter formula can set the disc only at the spiral arms (3KPC to 15KPC)?B. Why in the Bulge there is no Disc at all?C. Why the disc does not continue after 15KPC? Actually, do you confirm that when arm is ended, the stars after that point are ejected from the disc?D. Why the thickeners of the arm at the base is 3000LY while at the end it is 400LY? How Kepler law can explain this phenomenon3. Bar -Can you please explain how the same dark matter that aim to keep the orbital velocity of the stars in the galactic disc at a fixed velocity can suddenly increase so dramatically the orbital velocity of stars in this section? How the dark matter formula can justify that dramatic increase4. RingA. How the dark matter formula can justify the creation of the Ring?B. Why the ring is always created between the end of the bar to the base of the spiral arms?C. Why do you think that Kepler law works better with dark matter for this section?
What dark matter formula are you talking about? Scientists do indeed have ideas about what dark matter could be: axions, sterile neutrinos, WIMPS, and primordial black holes for example.