# Solution to the Galaxy Rotation Problem, without Dark Matter

Discussion in 'Alternative Theories' started by Scott Myers, Feb 2, 2013.

1. ### Scott MyersNewbieRegistered Senior Member

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Hypothesis:

Gravitational Time Dilation, described by General Relativity, sufficiently solves the galaxy rotation problem, without the need for dark matter. Time speeds up progressively from the galactic core outward, as predicted in GR, giving the appearance of higher radial velocity. This would also solve the paradoxical appearance, physical signature of the trailing arms of galaxies, which agree that stars are actually rotating slower the farther from the core they are relative, though observations seem to show otherwise. By keeping Kepler’s Law and applying Gravitational Time Dilation no Dark Matter is needed, and no alternative gravity explanation is needed.

Current Working Model from Wiki:

“The rotation curve of a disc galaxy (also called a velocity curve) is the dependence of the rotational velocity of the visible stars or gas in the galaxy on their radial distance from the center of the galaxy. This relationship can be summarized by a plot of the orbital speed (in km/s) of the stars or gas in the galaxy on the ordinate against the distance from the center of the galaxy on the abscissa.

A general feature of the galaxy rotation curves that have been measured is that the rotational velocity of the stars and gas are constant as far out as they can be measured (line B in the illustration), i.e. stars are observed to revolve around the centre of these galaxies at a constant speed over a large range of distances from the centre of the galaxy. If disc galaxies had mass distributions which were similar to the observed distribution of stars and gas, the rotation curves velocities should decline at large distances (dotted line A in illustration), in the same way as other systems with most of their mass in the centre, such as the Solar System of planets or the moons of Jupiter, following the prediction of Kepler's Laws. It is also observed that galaxies with a uniform distribution of luminous matter have a rotation curve that slopes up from the center to the edge, and most low surface brightness galaxies (LSB galaxies) rotate with a rotation curve that slopes up from the center, indicating little core bulge.

The galaxy rotation problem is the discrepancy between the observed galaxy rotation curves and the Newtonian-Keplerian prediction assuming a centrally-dominated mass associated with the observed luminous material. If masses of galaxies are derived solely from the luminosities and the mass-to-light ratios in the disk and core portions of spiral galaxies are assumed to be close to that of stars, the masses derived from the kinematics of the observed rotation and the law of gravity do not match. This discrepancy can be accounted for by a large amount of dark matter that permeates the galaxy and extends into the galaxy's halo.

Though dark matter is by far the most accepted explanation for the resolution to the galaxy rotation problem, other proposals have been offered with varying degrees of success. Of the possible alternatives, the most notable is Modified Newtonian Dynamics (MOND), which involves modifying the laws of gravity.[“

3. ### Janus58Valued Senior Member

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1. Do you honestly believe that they would have overlooked such an obvious solution? I mean what kind of ego does it take to assume that countless people with advanced degrees all missed something staring them in the face that you were able to see.

2. Gravitational time dilation simple isn't strong enough to produce the variation needed.

3. Even it was strong enough to create a noticeable effect, the effect wouldn't match what we observe. We observe outer stars going too fast. Time dilation would slow time as you got closer to the center. IOW, what you would see would be the outer stars orbiting at or close to the speed predicted by Newton and the stars orbiting slower than predicted as you moved towards the center. Instead, what we see is that stars close to the center orbit at or close to the Newton predicted speed and the outer stars deviate from the predicted speeds.

5. ### Prof.Laymantotally internally reflectedRegistered Senior Member

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Time dilation does not affect an objects velocity or appearent velocity!!!

7. ### Scott MyersNewbieRegistered Senior Member

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You assume.

Maybe since this is “such an obvious solution” you have some references, or math to show this vague statement of yours is true. You assume much.

You base this on what data? “Instead, what we see is that stars close to the center orbit at or close to the Newton predicted speed and the outer stars deviate from the predicted speeds”. The outer stars deviate from the predicted orbits relative to the other stars we observe in their relative orbits. You do not know which is ‘correct’, because we use the average speed of the overall orbits to determine the overall mass in a galaxy. To determine the ‘correct’ predicted orbit, we need to know the mass. This would be circular thinking by you. The proper time is correct in both frames, the one near the center of the galactic core, or the one at the outer edges of the galaxy. Either is correct within its frame, and only the observed difference in the orbital curve can be compared to the overall solution. We do not know the exact mass of what is being orbited; only good estimations, so I ask again how you know that the stars at the center follow the rule, but the ones farther out do not. You do not know this. If you do know this (somehow), please reference your data, unless it just came from within your ego.

Based on how we determine mass of nearby galaxies, the ones near the median radial distance outward, are closest to the correct Keplerian orbits, as observed by us. From there, time would speed up as we go farther away, and would slow down as we near the galactic center, showing this flat curve we observe.

Last edited: Feb 3, 2013
8. ### Scott MyersNewbieRegistered Senior Member

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In Special Relativity no, but in General Relativity, I'm not sure this is one hundred percent true. Time dilation in General Relativity agrees in all frames, because it is due to actual mass, rather than apparent mass due to acceleration, no?

9. ### brucepValued Senior Member

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There's no such thing as apparent velocity. Mass is an invariant. It's not frame dependent. We already know that dark matter exists as natural phenomena. We already know how much of it exists. We just don't know all the details since the only strong interaction with matter is gravitational. There's one proposal called Mirror Dark Matter which predicts a very weak electromagnetic interaction can occur between Mirror Dark Matter and matter. Scott if you're really interested in this science listen to what Janus said to you. Learn the science. Did you read Aqueous Id post #95 in thread "Light is frame-dependent in PF, but constant in SR"? It's great advice for those of us interested in the science.

Last edited: Feb 3, 2013
10. ### Scott MyersNewbieRegistered Senior Member

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What 'apparent velocity' and what do you know about Sirius B?

Without GR, and Gravitational time Dilation considered, we would be wrong about Sirius B, and many other things. We have one problem that uses dark matter as the solution. I say there is another possibility to be worked out. Where else do we need Dark Matter? What other problem does Dark Matter solve? If there is another possible explanation that uses current accepted physics, why not explore it?

The concept is fine, but would need some math to prove it possible, or likely. If it can be disproven, I'm just as happy, but let's try that instead of this thread going in four different directions. Show me why Gravity Time Dilation should apply in a lab, or be shown as predicted with our GPS satellites, but cannot be considered valid while making observations of hugely massive structures like galaxies?

Who said mass is "variant"? I said we determine the mass of Galaxies by using the average rotational speed of the stars that are orbiting the galaxy. The answer is estimated, and would be "variant", if we do not include the effects of Gravity on the spectrum we are using to determine velocity, and subsequently the mass.
Reasons like, "we know because we know", or "it's not enough" are far too vague. Give us something to chew on would you?

Let’s go on to disprove this idea of mine then, with some good estimates about how the math will affect the time dilation, and our observed spectrum. Time Dilation is the same as Red Shift or Blue Shift, of emitted light. How would my idea affect the spectrum we observe from one side of the galaxy (moving toward us) and the opposite side (moving away from us); how much would be Doppler shift and how much is from Gravity Time Dilation? How would this appear to our observed radial velocities?

Saying it is just not there, or measurable is not an answer. It’s a known observable working theory called General Relativity. How much this is effecting our observations of the Galaxy Rotational problem is the question.

11. ### OnlyMeValued Senior Member

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Dark matter plays into both observed galactic rotations and some distant and otherwise unexplained gravitational lensing.

12. ### Scott MyersNewbieRegistered Senior Member

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Very well, yes. There are issues with some observations apparently, but this is reasonable. This is better evidence than the Galaxy question certainly. I think.

Does this exerpt explain well enough?

"The most direct observational evidence to date for dark matter is in a system known as the Bullet Cluster. In most regions of the universe, dark matter and visible material are found together,[38] as expected because of their mutual gravitational attraction. In the Bullet Cluster, a collision between two galaxy clusters appears to have caused a separation of dark matter and baryonic matter. X-ray observations show that much of the baryonic matter (in the form of 107–108 Kelvin[39] gas, or plasma) in the system is concentrated in the center of the system. Electromagnetic interactions between passing gas particles caused them to slow down and settle near the point of impact. However, weak gravitational lensing observations of the same system show that much of the mass resides outside of the central region of baryonic gas. Because dark matter does not interact by electromagnetic forces, it would not have been slowed in the same way as the X-ray visible gas, so the dark matter components of the two clusters passed through each other without slowing down substantially. This accounts for the separation. Unlike the galactic rotation curves, this evidence for dark matter is independent of the details of Newtonian gravity, so it is claimed to be direct evidence of the existence of dark matter.[39] Another galaxy cluster, known as the Train Wreck Cluster/Abell 520, appears to have an unusually massive and dark core containing few of the cluster's galaxies, which presents problems for standard dark matter models.[40]"

13. ### brucepValued Senior Member

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The apparent velocity Prof Dumbbell referred to. You associated the extra mass to time dilation. Mass is an invariant. Not frame dependent. Your concept is nonsense. Here's what I suggest. Go find out why it's nonsense and learn some physics in the process. Don' delude yourself into thinking you know anything about gravitational physics. You don't.

14. ### Janus58Valued Senior Member

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Take a typical galaxy, 100 billion stars and 100,000 ly across. The comparative predicted to observed rotation curves look something like this:

With A being the Newtonian prediction and B the observed rotation.

If I pick a star about halfway out (25,000 ly) and use the gravitational time dilation formula:

$T_0 = T\sqrt{1- \frac{2GM}{rc^2}}$

Compute the time dilation factor, and then do the same for a star twice as far out(50,000 ly), you can compare the relative time dilation for the two. It works out to a be a factor of 1.000000003.

This means that gravitational time dilation could only account for that much of the difference in orbital speed. Now, from the diagram, it is easy to see that even to get a star located at a distance marked by the far right of the chart to orbit at the same velocity as one at the halfway point (Let alone get them up to where the 'observed' line is) would take much more than a 0.0000003% change of its velocity.

The predicted curves are made based on the amount of visible(using all detectable electromagnetic radiation) matter in the galaxy. In other words, close to the core, the stars orbit at the proper speeds for the matter we see, and we get further out they start to orbit faster than they should for the visible matter. What we do not see is inner stars orbiting slower than they should considering the matter we see there.

If anyone is suffering from ego issues here, it's not me. I have no dog in this fight. It really doesn't matter to me whether Dark matter turns out to exist or not in the long run. But if I am going to entertain the idea of an alternate explanation, it at least needs to be reasonable.

15. ### AlphaNumericFully ionizedRegistered Senior Member

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This is why it is important to have details in a model. It is easy to arm wave and say "Oh perhaps you just forgot about...." but if you don't know the model used to do the simulations you have no idea what was forgotten or included in the model.

Besides, galaxy rotation curves are only one piece of evidence for dark matter. Other things like the Bullet Cluster are evidence and cannot be explained by modifying gravitational models in the ways proposed by people who dislike DM.

/edit

Just saw the Bullet Cluster has already been mentioned....

/edit again

You've got your methodology backwards. The onus to do the 'demonstrate this valid' is on someone asserting an explanation. You don't get to say "This sounds reasonable, someone prove me wrong". Instead it should be "I'm going to demonstrate that this is a reasonable explanation by working out quantitative predictions and comparing with experimental data". Once you do that we can compare alternative explanations and see which is best. Until this is done by you or anyone else the default position is disbelief, ie "I do not accept your claims are true" (note this is different from "I believe your claims are false").

16. ### Prof.Laymantotally internally reflectedRegistered Senior Member

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There is no apparent velocity. That has been the point I have been making. Velocity is just that, its velocity. People try to make it sound like there is some other velocity that can be observered by someone in another frame, but it is simply not true. An object cannot be at two different velocites at the same time, and since spacetime dilation is not just an illusion of their apparent time and distance, then it cannot give the illusion of an apparent velocity, so it truly does not exist!

Mass is not an invariant! There is a relative mass increase that was discovered by Einstein! This theory has not been proven to be wrong! Just because it is not mention in the book Exploring Black Holes : Introduction to General Relativity does not mean that it does not exist! I could tell you the same, in that you have deluded yourself into thinking you know everything about graviational physics just because you have read that book! I found it to be very biased in some areas and is being used as a tool to push their own ideas and opinions about theoretical physics that is not accepted by the scientific community! Just because they work at the most expensive schools in the country doesn't mean that they are correct about everything! That does not give them the right to push their own opinions as scientific fact!

I would think if they failed to consider relativistic mass then problem solved. No wonder there is dark matter, they failed to use equations made by Einstein that developed the General Theory of Relativity. How could it possibly work out correctly? But, I don't think that they really have! Like I said, they just didn't put it in that one book you read!

17. ### Prof.Laymantotally internally reflectedRegistered Senior Member

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Here is a quote from that book : "The fact that no object moves faster than the speed of light is sometimes "explained" by saying that "the mass of a particle increases with speed." This interpretation can be applied consistently, but what could it mean in practice? Someone riding along with a faster-moving stone detects no change in the number of atoms in the stone, nor any change whatever in the individual stoms, nor in the binding energy between atoms. Our viewpoint in this book is that mass is an invariant,..."

This was my own theory that I proposed on the internet, that then has been slandered in this book, written by prof.'s at MIT and Princton University! I proposed that this explaination was incorrect. Seems like your money would not be well spent here, when they change the laws of physics at their own whim because a layman pointed something out to people on the internet! The worse part of it all is that they then took it into their own direction that I don't even agree with, and I did not prove Einsteins Theory wrong! I was just proving the explaination as mentioned was wrong! So then it is just my own misinterpreted BS! I surly wouldn't go to school there if they are just going to throw my own misinterpreted BS back at me!

I was telling people that the explanation doesn't actually conform to GR! So then GR would not be false, just the explaination! Seems like no one was able to show this before, and when they did it turned out to be incorrect! So they just did away with mass increase in relativity, just because they didn't grasp how the explaination itself doesn't even conform to relativity!!! They just said, oh our layman description does not come out correct so lets do away with one of Einsteins theories! When the fact of the matter is that their layman description was false and didn't obey the axioms of relativity to begin with!!!!

Last edited: Feb 4, 2013
18. ### Scott MyersNewbieRegistered Senior Member

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This is fair.
I'm looking for some assistance on the math, and proposing some ways to model this within currently accepted rules. I’m not asking here, I’m exploring other options. You are correct. I am, intrigued, however, by some who put so much energy into saying an idea is bogus, without putting forth the effort to actually debunk it. My point in asking someone to disprove it is not me saying,’ it is true until you prove me wrong’. That is not at all meaningful, nor do I care that much about one small idea. I thought it worth exploring, and I will explore it until I know it is wrong. This can take a matter of days, or weeks, depending on what needs to be resolved in the question. Help prove me wrong, and I move on. I have no problem with consensus. I have demonstrated my ability to be wrong before, and perhaps this will be another opportunity. General Arm waving is equally impressive in either case.

Though the Bullet Cluster was mentioned, needs to be addressed: “and cannot be explained by modifying gravitational models in the ways proposed by people who dislike DM.”
Yes, but as yet, “those who dislike DM.” are not I. I do not like, or dislike, Dark Matter. I don’t care either way, but so far; these (alternative) proposals have tried to change the properties or effects of gravity over distance, or extreme conditions/supermassive objects. I’m not proposing any change of how gravity works over some scale, or dimension, or anything outside the workable accepted mathematic model. The current arguments are equal to a Tired Light theory in my book. “Well… the light got tired of course, that’s why the math doesn’t work.”

There is no book behind my thoughts, no real agenda, unless otherwise potentially identified and squashed, no intent other than to consider alternative solutions to things we ‘sort of know’.

I will reply to some other posts as soon as I can, but in the meantime: I mentioned in the proposal the signature appearance of the spiral galaxy vortex that looks as though the stars in a galaxy follow Kepler’s third law. Does anyone have a physical model of how the appearance would change if we applied our current model to a physical animation? I.e. this: http://www.youtube.com/watch?v=XofdAva73PM ????? The other animation would be helpful, but I just haven’t found one.

Thanks fellas

19. ### Scott MyersNewbieRegistered Senior Member

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It is the Newtonian predicted curve, without parameters. This shows only a relationship, clearly, though it is based on real collected, observed data. The starting point as being correct is not the point of the curve differential chart, nor can that be inferred from the picture here. More about our starting point later in this post.

What mass did you use? What radius of central mass did you use? Did you use the estimated mass and radius of the ‘likely’ supermassive black hole? Is this Andromeda’s core, or the one in the Milky Way? What if we use the central bulge of either Galaxy for our mass/density for the equation; how would that effect our calculation at 25,000 and 50,000ly? The central mass (bulge) of Andromeda is about 1/6th the overall mass (typically), of the galaxy type. The Supermassive Black Hole, though far denser, is a mere 10 million solar masses. The central bulge is closer to 166 billion solar masses, but covers 10,000 ly’s.
Not only do I not know what you started with, but what did you resolve by expressing percentage of velocity. We are using redshift/blueshift to determine velocity. There are two ways of resolving our equation to have a standard here. One way is to express your solution is proximity to light speed i.e., 0.25, or the same number would appear as 75,000 KM/s, or their negative counterparts. Those are the same number (value) BTW.

What matter do we see? That’s philosophically entertaining, since we are presuming some 84% of something we have never seen, witnessed or observed is what you are defending, above and beyond “(using all detectable electromagnetic radiation)” There is no, though this is acceptable to, even me, if there is no other way.

“What we do not see is inner stars orbiting slower than they should considering the matter we see there.” This is true, but only because we determine mass by reading our inherent velocity via spectrum shift, to determine the central mass. Of course this will agree with Newtonian predictions, and Kepler’s third law. We determine mass (current model) by using our radial velocity. How could we have any other solution? I think perhaps you may be thinking of Time Dilation in a sort of backwards way. Time Dilation is most effective and apparent the closer you get to a gravitational well. It is not the other way around. Zero Time Dilation would be a region of space that would have Zero gravitational affects. The most proper way to put real data to our differential chart, would be to accept Gravity Time Dilation as most effective near the (agreed upon) central mass. Resolve the maximum potential, and work out progressively from there. If we are determining mass from say, the blue stars rotating around Andromeda’s Black Hole, we have to adjust for Time Dilation there first. This is what I need to see has been done. If it has been than let’s have it. Where is this documented?

Yes, let’s be reasonable then, and work on some standard parameters we can work with, and get on the same pager with exactly what we are talking about. Something else that needs to be nailed down, is what is the actual difference (expressed in KM/s) from the Newtonian predictions, regarding orbits at several benchmarks radially, and the ‘observed’ radial velocities that have flattened out the curve creating the necessity of Dark Matter. I’ll see what I can come up with in the data on that, but obviously needs to be concluded. This is most likely not the case, but what if the difference in the curve is only, 0.00000003%. Until I have a good hard number to work with regarding the difference, I surely would not know.

As well; the link I shared displaying the animated Keplerian orbits, and the signature appearance of the trailing arms of a galaxy need not change, no matter our conclusions. The difference in appearance would be too small to require another animation. It’s not as though, in our current model, there are rigid spokes emanating from a galactic center. A model like that would require acceleration in the rotation of stars as we proceed outward from the galactic center. The average speed of stellar objects rotating around Andromeda’s galactic center, for instance, at 300KM/s would still appear to ‘trail’ as the physical appearance implies. Both models agree with the physical appearance we witness, just at varying magnitudes.

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22. ### Scott MyersNewbieRegistered Senior Member

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Good read, but doesn't address my concerns really. Both the arguments simply deal with minor variables regarding the thickness of the disk vs. the plane of the disk, average estimated densities, and local densities. Thanks for the post though. The more we know about what ideas are out there, the better, we know. Both models work under the assumption of common frames with commoving objects involved, which they should. That is the only Instance of Time Dilation considered in the math contained in both models. The Kinematic Time Dilation potential is small enough that it need not be considered; especially since it would be undetectable from our third observer position.

23. ### Robittybob1BannedBanned

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@Scott Myers - were you able to read and understand that paper? Pretty complex study.
@ AlexG - were you right into the science being discussed there, or did you just think it might answer Scott's question?