Galactic rotation curves indicate roughly linear angular momentum gradients. I.e. for identical (solar) masses the tangential velocity is roughly fixed even as radius varies. A Keplerian curve corresponds to angular momentum that varies as square root of radius. If there is larger dissipation in the inner radii, the angular momentum loss being larger for inner radii could produce a linear a.m. gradient as observed commonly today. At same time, mass density at the center increases through dissipation as well.
Hi guiding_light,
It seems to me that the only explanation for this anomalous behavior is relativistic frame dragging. In that sense galaxies are not moving as "orbiting" material but as contiguous "Islands" of mutually moving mass all under some "pooled" property of spin.
Cheers
It seems to me that the only explanation for this anomalous behavior is relativistic frame dragging. In that sense galaxies are not moving as "orbiting" material but as contiguous "Islands" of mutually moving mass all under some "pooled" property of spin.
Cheers
Good Elf,
I have tried to get you to reply to a question, you seem to be the only one that is active around this web site that is not opinionated.
I read one on excuse me if I do not spell it right, Su?kind on string theory, over my head. I read you, RealityCheck, and many others, but I understand you all do not like people who do not register, but until I understand, I do not want to give out my email. I believe that is a valid point. I am so ignorant at this stage, and young. This Z guy keeps covering up everything I ask and you never answer and I have tried to for many, many weeks. I do not know where to go to get you to reply because Z just keeps on posting and I get covered up.
Is it because I am in HS, or just because I will not register. I have not said anything wrong, and my dad said until I learn more I cannot expect to interact with the men on this site. So please explain to me, who is the right people to read. You I know, RealityCheck, 000Joshua, They, and you made some comment about Yquantum on super strings about something he will do or say, cannot remember. Should I not read her or him any more, I do not have a clue who is who, and I am trying to learn as much as this mind can handle?
I do not want to make anyone mad. I am sure everyone is great, but this Super String Theory is new to me!
Please let me know who I should read, I am reading everything I can find in the library on the subject now.
Hope Zep does not cover this one up?
Zero
I have tried to get you to reply to a question, you seem to be the only one that is active around this web site that is not opinionated.
I read one on excuse me if I do not spell it right, Su?kind on string theory, over my head. I read you, RealityCheck, and many others, but I understand you all do not like people who do not register, but until I understand, I do not want to give out my email. I believe that is a valid point. I am so ignorant at this stage, and young. This Z guy keeps covering up everything I ask and you never answer and I have tried to for many, many weeks. I do not know where to go to get you to reply because Z just keeps on posting and I get covered up.
Is it because I am in HS, or just because I will not register. I have not said anything wrong, and my dad said until I learn more I cannot expect to interact with the men on this site. So please explain to me, who is the right people to read. You I know, RealityCheck, 000Joshua, They, and you made some comment about Yquantum on super strings about something he will do or say, cannot remember. Should I not read her or him any more, I do not have a clue who is who, and I am trying to learn as much as this mind can handle?
I do not want to make anyone mad. I am sure everyone is great, but this Super String Theory is new to me!
Please let me know who I should read, I am reading everything I can find in the library on the subject now.
Hope Zep does not cover this one up?
Zero
Dear Good Elf,
I think maybe you need to explain this to me. I hesitate to make any guesses about what you stated.
As we do expect the inner objects to move faster, we should expect some resistance of relativistically orbiting objects to moving at higher speeds.
Thanks,
g_l
QUOTE
It seems to me that the only explanation for this anomalous behavior is relativistic frame dragging. In that sense galaxies are not moving as "orbiting" material but as contiguous "Islands" of mutually moving mass all under some "pooled" property of spin.
I think maybe you need to explain this to me. I hesitate to make any guesses about what you stated.
As we do expect the inner objects to move faster, we should expect some resistance of relativistically orbiting objects to moving at higher speeds.
Thanks,
g_l
Hello, guiding light, Goodly Elvish One -
GE - nice comments on the Zwieback book.
GL - a.m. doesn't seem to be conserved in your example...any thoughts?
-ss
GE - nice comments on the Zwieback book.
GL - a.m. doesn't seem to be conserved in your example...any thoughts?
-ss
Hi ss,
Yes, the picture I was playing around with was that through some mechanism the inner radii masses lost angular momentum more rapidly than the outer radii.
If we have a large mass M providing the gravitational force, then with simple circular motion we have GMm/r^2 = mv^2/r, or GMm^2r=(mvr)^2=(am)^2.
So a.m. is proportional to square root of r for the Keplerian case.
For observed rotation curve, v is constant, so mvr varies linearly with radius.
To evolve a (radius)^1/2 curve into a linear curve, the angular momenta at different radii need to change but in different amounts. Rather than having masses gain angular momentum, why not have them lose angular momentum through some dissipation mechanism? In that case, since the slope is divergent as r->0, it is preferable to have larger dissipation as r->0, so that the slope of v(radius) falls in line with the outer radii.
g_l
QUOTE
a.m. doesn't seem to be conserved in your example...any thoughts?
Yes, the picture I was playing around with was that through some mechanism the inner radii masses lost angular momentum more rapidly than the outer radii.
If we have a large mass M providing the gravitational force, then with simple circular motion we have GMm/r^2 = mv^2/r, or GMm^2r=(mvr)^2=(am)^2.
So a.m. is proportional to square root of r for the Keplerian case.
For observed rotation curve, v is constant, so mvr varies linearly with radius.
To evolve a (radius)^1/2 curve into a linear curve, the angular momenta at different radii need to change but in different amounts. Rather than having masses gain angular momentum, why not have them lose angular momentum through some dissipation mechanism? In that case, since the slope is divergent as r->0, it is preferable to have larger dissipation as r->0, so that the slope of v(radius) falls in line with the outer radii.
g_l
Hey, GL -
Just off the top of my head, the diff. in your values is likely due to the bodies being spinning bodies, so they have their own a.m. I can't quite remember the formula, but you will have to incorporate the effects that the spinning sphere a.m. has on the total a.m.
The motion is not effectively "simple", since there are at least 2 contributors to total a.m., and likely more. Aamof, since the angle is off for us and a couple of other planets, so that will have to be taken into account, too.
-ss
Just off the top of my head, the diff. in your values is likely due to the bodies being spinning bodies, so they have their own a.m. I can't quite remember the formula, but you will have to incorporate the effects that the spinning sphere a.m. has on the total a.m.
The motion is not effectively "simple", since there are at least 2 contributors to total a.m., and likely more. Aamof, since the angle is off for us and a couple of other planets, so that will have to be taken into account, too.
-ss
Hi "In the dark intelligently like z", solidspin, and guiding_light,
If it was able to be ingested then "A First Course in String Theory" by Zwieback would be the way to go. As Solidspin has mentioned I have started to read this one myself and it is very enlightening.
If that passage from Susskind that Yquantum originally posted is "above your" that is going to be scary. My suggestion is to google all the hard terms as you come to them by having a page of google open and type in "meaning of ---" or "define ----". Eventually you will "progress". Perhaps the next level from there (up ... down) will be "The Elegant Universe" by Brian Greene. There is an on-line TV Presentation of this on Nova I think (much simplified). You would find it in my back references... shoot here it is!
http://www.pbs.org/wgbh/nova/elegant/
Just need cable to stream it to you.
http://www.pbs.org/wgbh/nova/elegant/program.html
The book is better. That goes through all the ideas slow and easy.
Here is an excerpt from the book...
http://www.wwnorton.com/catalog/fall03/greene1.htm
Guiding Light... Frame dragging is a gravitational process of "entraining" matter to move as in a kind of "gravity field drive". Read up on Gravity Probe B. This is the tangential form of this process. There is a linear form of this as well. Matter tows other matter around due to the curvature of spacetime. If matter is not exhibiting orbital motion the first thing I would suspect is this phenomena. We know that spiral galaxies have far too much mass to be "for real". Some kind of dark matter is involved. This is providing extra gravitational influence. Rather than each "particle" orbiting other particles in a "flatspace" it is my contention that mass is curving dimensions in the "Uberspace" and resulting in a gravity "pool". What this does is a kind of emergent behavior of this matter to entrain all the particles together as if each particle is towing all the other particles around and visa versa.
Why don't they all flop into a single black hole? It is subject to the gravitational equivalent of a Faraday's cage effect if it is homogeneously distributed over large volumes. What this means is unlike black hole formation where the attraction is purely through orbiting matter... in entrained matter "clouds" (whatever the matter might be) the further inside this highly dispersed "swarm" of particles... the less the attraction in any "particular direction". This is because the attraction works effectively like a partially hollowed out "sphere" of uniform density. Wherever you are on the inside of this sphere a smaller sphere whose surface is centered on your position indicates mass attraction from points "more central to the swarm" and points outside your "sphere" have little effect on you in similar fashion to the way charges reside on the surface of a charged sphere (inverse square law canceling effects... high school stuff really). This is generalized to a uniform distribution of "mass charge". Particles are attracted into the "cloud" of matter and the further into the cloud you progress the lower the gravitational acceleration becomes. A sort of "Hilbert Field". At the exact center of the "cloud" the mutual attraction as emergent behavior is dynamically balanced in all directions. Once a particle is in such a condition all the particles begin to move as one (like a flock of birds). The inertial frames of reference are all dragged with it as well. In a strange fashion according to General Relativity all the particle are "frame dragged" not only in space but in time as well. Of course the "cloud" of particles are a galaxy. I wrote a paper on this effect "a long time ago... in a galaxy far far away"... he he he!
I don't know what dark matter is but given that it is there... this will be what is happening.
Cheers
If it was able to be ingested then "A First Course in String Theory" by Zwieback would be the way to go. As Solidspin has mentioned I have started to read this one myself and it is very enlightening.
If that passage from Susskind that Yquantum originally posted is "above your" that is going to be scary. My suggestion is to google all the hard terms as you come to them by having a page of google open and type in "meaning of ---" or "define ----". Eventually you will "progress". Perhaps the next level from there (up ... down) will be "The Elegant Universe" by Brian Greene. There is an on-line TV Presentation of this on Nova I think (much simplified). You would find it in my back references... shoot here it is!
http://www.pbs.org/wgbh/nova/elegant/
Just need cable to stream it to you.
http://www.pbs.org/wgbh/nova/elegant/program.html
The book is better. That goes through all the ideas slow and easy.
Here is an excerpt from the book...
http://www.wwnorton.com/catalog/fall03/greene1.htm
Guiding Light... Frame dragging is a gravitational process of "entraining" matter to move as in a kind of "gravity field drive". Read up on Gravity Probe B. This is the tangential form of this process. There is a linear form of this as well. Matter tows other matter around due to the curvature of spacetime. If matter is not exhibiting orbital motion the first thing I would suspect is this phenomena. We know that spiral galaxies have far too much mass to be "for real". Some kind of dark matter is involved. This is providing extra gravitational influence. Rather than each "particle" orbiting other particles in a "flatspace" it is my contention that mass is curving dimensions in the "Uberspace" and resulting in a gravity "pool". What this does is a kind of emergent behavior of this matter to entrain all the particles together as if each particle is towing all the other particles around and visa versa.
Why don't they all flop into a single black hole? It is subject to the gravitational equivalent of a Faraday's cage effect if it is homogeneously distributed over large volumes. What this means is unlike black hole formation where the attraction is purely through orbiting matter... in entrained matter "clouds" (whatever the matter might be) the further inside this highly dispersed "swarm" of particles... the less the attraction in any "particular direction". This is because the attraction works effectively like a partially hollowed out "sphere" of uniform density. Wherever you are on the inside of this sphere a smaller sphere whose surface is centered on your position indicates mass attraction from points "more central to the swarm" and points outside your "sphere" have little effect on you in similar fashion to the way charges reside on the surface of a charged sphere (inverse square law canceling effects... high school stuff really). This is generalized to a uniform distribution of "mass charge". Particles are attracted into the "cloud" of matter and the further into the cloud you progress the lower the gravitational acceleration becomes. A sort of "Hilbert Field". At the exact center of the "cloud" the mutual attraction as emergent behavior is dynamically balanced in all directions. Once a particle is in such a condition all the particles begin to move as one (like a flock of birds). The inertial frames of reference are all dragged with it as well. In a strange fashion according to General Relativity all the particle are "frame dragged" not only in space but in time as well. Of course the "cloud" of particles are a galaxy. I wrote a paper on this effect "a long time ago... in a galaxy far far away"... he he he!
I don't know what dark matter is but given that it is there... this will be what is happening.
Cheers
Hi ss,
Addition of spin and orbital angular momentum is good to keep in mind. Thanks.
Dear Good Elf,
Thanks for the reference to Gravity Probe B. It is widely held that there is a black hole at the galaxy center. This should provide a source of attraction for the innermost radii. Also if it were spinning and dragging space-time with it, that might also help to speed up the nearest objects. Yet despite these two factors, outer radii still move "fast enough to catch up". Looks to me like much larger orbital angular momentum.
Thanks,
g_l
Addition of spin and orbital angular momentum is good to keep in mind. Thanks.
Dear Good Elf,
Thanks for the reference to Gravity Probe B. It is widely held that there is a black hole at the galaxy center. This should provide a source of attraction for the innermost radii. Also if it were spinning and dragging space-time with it, that might also help to speed up the nearest objects. Yet despite these two factors, outer radii still move "fast enough to catch up". Looks to me like much larger orbital angular momentum.
Thanks,
g_l
Hi guiding_light,
For galaxies with black holes in the center... I guess it is a case of a little from column "A" plus a bit from column "B".... he he he! Remember not all galaxies "have to have" a black hole in their center.
Nothing is ever the "last word' in science and there are always exceptions and there will be new cases too. This is only "my opinion". Time to get the computers out and to run simulations eh!
The "excess mass" over "visible mass" ratio is about 6 to 1. This supplies an awful lot of "excess kinetic energy" and bulk gravitation to a system if you are only looking at the visible stars. We are not speaking about 'small discrepancies here"... he he he! The black hole may only account for a small percentage of the overall galactic mass even if it contains thousands of solar masses in total. What usually happens is it "eats" all the local stars and that means it (black hole) is now on a "diet" since nothing is in their local region just now. It has really only "redistributed" the mass slightly in that region. It does not necessarily follow that the 'personal space' of the black hole is going to get filled with other stars immediately. Space is still a very empty place and a black hole is a very small target, frame dragging is a bulk property of the space not affected by a trite local issue such as a "black hole"... of course I could be wrong.. there will be more exceptions etc.
There are a lot of different geometries to account for.... there is not just one model for galaxies or even spiral galaxies. Generalizations always fail almost in every case when you choose "specifics". That large orbital angular momentum you speak of will not reflect the stars as much as it reflects the so called "dark matter".
Cheers
For galaxies with black holes in the center... I guess it is a case of a little from column "A" plus a bit from column "B".... he he he! Remember not all galaxies "have to have" a black hole in their center.
Nothing is ever the "last word' in science and there are always exceptions and there will be new cases too. This is only "my opinion". Time to get the computers out and to run simulations eh!
The "excess mass" over "visible mass" ratio is about 6 to 1. This supplies an awful lot of "excess kinetic energy" and bulk gravitation to a system if you are only looking at the visible stars. We are not speaking about 'small discrepancies here"... he he he! The black hole may only account for a small percentage of the overall galactic mass even if it contains thousands of solar masses in total. What usually happens is it "eats" all the local stars and that means it (black hole) is now on a "diet" since nothing is in their local region just now. It has really only "redistributed" the mass slightly in that region. It does not necessarily follow that the 'personal space' of the black hole is going to get filled with other stars immediately. Space is still a very empty place and a black hole is a very small target, frame dragging is a bulk property of the space not affected by a trite local issue such as a "black hole"... of course I could be wrong.. there will be more exceptions etc.
There are a lot of different geometries to account for.... there is not just one model for galaxies or even spiral galaxies. Generalizations always fail almost in every case when you choose "specifics". That large orbital angular momentum you speak of will not reflect the stars as much as it reflects the so called "dark matter".
Cheers