The rotation of galaxies can not be described properly with the mass that we can see, so the standard cosmology added dark matter. I don't know exactly the dynamics of this system or the equations used to compute all this but I thought that maybe this differential rotation can be explained by the aberration of gravity having a finite propagation speed. From your estimate of the minimum speed of gravity (2*10^10) this aberation is not observable at the solar system scale but maybe it has an effect at the galaxy scale ... May be I am all wrong and the aberation would have the contrary effect of what is observed.???
You would do well to read Tom's book since he already explains the flat rotation of galaxies using the idea of the finite propagation distance of gravity.
quote: You would do well to read Tom's book since he already explains the flat rotation of galaxies using the idea of the finite propagation distance of gravity.
I read an article on the idea of the finite propagation distance of gravity and found it very interesting, but my idea use an infinite propagation distance with a finite propagation speed of gravity. The finite speed of propagation imply that their will be an aberration. I am not a mathematician and my question is: will the aberration produce the observe effect on the rotation of galaxy?
quote: my question is: will the aberration produce the observe effect on the rotation of galaxy?
Aberration will tend to accelerate the orbiting body over time and make it escape the system, it does not produce a constant velocity profile as what is observed for galaxies.
quote: my question is: will the aberration produce the observe effect on the rotation of galaxy?
Aberration will tend to accelerate the orbiting body over time and make it escape the system, it does not produce a constant velocity profile as what is observed for galaxies.
Can you explain me exactly what is observed with the rotation of galaxie.
quote: what grid msystem are using for an universe, where are you putting it in a grid? that will tell you where it has moved since then!! Please explain
The intuitive mind
Eucledian infinite 3d orthogonal. Observing spiral galaxy from the top give us an "instanous" view. Spectrum of inclined galaxy give us rotation speed. What was observed that does not fit with the standar model prediction based on the mass estimate of luminous mater? I know that it does not fit. I know that the standard model need to add dark mater and black hole to make it fit. But I don't remember exactly wath was observed
I am speaking of galaxy rotation. The mesurement of this rotation use red-shift and blue-shift. Take the spectrum of a serie of regions that goes across the galaxy disk. When the galaxy is inclined one side of the galaxy will come in our direction (blue-shift) and the other side will go away from us (red-shift). Making the shift difference between symetric regions (rigth-left same distance from the center) give us a curve for the rotation in function of the distance from the center.
quote: my question is: will the aberration produce the observe effect on the Can you explain me exactly what is observed with the rotation of galaxie.
The rotation rate gradually increases from the center to a maximum value and then remains pretty constant the rest of the way. The sharpness of transition from the center is related to the luminosity of the galaxy. Towards the near center of galaxies sudden increases in velocity have been observed, this is thought to be due to a supermassive object at the center.
Applying the inverse square law to the areas near the galactic centers calls for the invention of dark matter to satisfy the accelerations noticed. Since the galaxies tend to exude more stars and material then they should, some have said that matter is created ex nihilo in their centers by some mysterious and unmodelled processes. Is gravitational screening the answer? Does the rotational axis in combination with the finite range of gravity suggest that eventually all of the matter both detectable and hidden can be pulled out of the galaxy? Esophagoplasty monoarylated superregenerator viridite renneting brioche reticulated flax colpopathy bowsaw corniche caudex anoesis embellisher xylidino?
Thank you Jeremy. I took a minute and did a search and found a lot of paper on that. Most rotation curves look very similar:http://bustard.phys.nd.edu/PH308 Mesured rotation curves This one give the formalas for different mass distribution. http://www.pas.rochester.edu/~dmw/ast142/Lectures/Lect_16b.pdf The constant density, spherical symmetri fit with the rotation of the center part of the galaxy (incresse in velocity) and the 1/r2 density model fit the rest of the curve (constant). Do you know if the change of function happen between the bulge and the disk of the galaxy?
MarkVitrone
quote:Since the galaxies tend to exude more stars and material then they should
I was not aware of that. Can you give me some explanations?
"Towards the near center of galaxies sudden increases in velocity have been observed, this is thought to be due to a supermassive object at the center."-MV
are you thinking blackholes at the center of the galaxie? if so there is evidence to prove that idea, the fact that they(blackholes) spin can cause the arms of the galaxie we live in!
quote: -------------------------------------------------------------------------------- Since the galaxies tend to exude more stars and material then they should -------------------------------------------------------------------------------- well shouldn't we deal with the matter can we can keep track of now instead of saying what created it, excluded something?
The intuitive mind Esophagoplasty monoarylated superregenerator viridite renneting brioche reticulated flax colpopathy bowsaw corniche caudex anoesis embellisher xylidino?
From what I read the gravity aberration (infinite range, finite speed) would not explain the rotation of galaxies. The main factor in the standard model is the total mass and its distrubutions. Calculation gave 90% of dark matter and 10% for the seeable matter. I think that we don't see all matter (brown dwarf hydrogen cloud...) but the estimate of the mass of this baryonic dark matter is not enough. OK so invent the non-baryonic matter...
What else? The Meta Model with a limited range for gavity explain the rotation of galaxies. But what about galaxies cluster? How are they held together? And what about those giant elleptical?
The acceleration of the rotation near the center need a big mass in a small volume. This suggest a big big black hole having the mass of millions suns. Other sugestions ?
Back to rotation: The gravity of the blackhole follow the Kepler inverse square because it is so small, so it will not have a big effect on the rotation off the arms. I saw some others models implying two elleptical each having a blackhole, collide and merge to give a spiral. http://www.polaris.net/~ksn/ Good lecture!
Differential rotation of galaxies
Posted - 05 Dec 2002 : 17:35:18
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