Explination for Dark Matter

reply to post by XPLodER


The first option is fine as long as we observe such a "gear"-like phenomenon occurring. More importantly, it also has to be finely tuned to allow the gravitational field to impart angular momentum without also imparting any significant gravitational attraction. It's possible, but I'd call it the lesser of the two options.

The second option might be possible, I don't know... it depends what type of "energy" you mean, I guess.

Originally posted by CLPrime
reply to post by XPLodER

 

The first option is fine as long as we observe such a "gear"-like phenomenon occurring. More importantly, it also has to be finely tuned to allow the gravitational field to impart angular momentum without also imparting any significant gravitational attraction. It's possible, but I'd call it the lesser of the two options.

The second option might be possible, I don't know... it depends what type of "energy" you mean, I guess.

a third option is that the medium between galaxies is of a different medium density than the galaxies themselves and a hydrodynamic constriction in the "flow" of the medium between two galaxies would create an attractive force between the two bodies but also impart external rotational energy into the galaxies.

as for the energy and what it is defined as and what created it in the first place
i do not know

xploder

reply to post by CLPrime

I can match you Paint drawing for Paint drawing.

It usually helps if you understand what you are talking about.

There's no "what I think is happening."

Actually, there is a substantial amount of it... allow me to explain:

There's only what's really happening, according to the physics.

Which you are apparently unaware of.

Light is following a straight line through the gravity well of the sun.

So far, so good.....

Photons from distant stars are not significantly affected by another star's gravity well until they get nearly tangential to the star or to any given external circumference (such as the orbit of the Earth).

And this is where your "Belief" that you know what it happening falls apart completely.

The gravity well of the star extends outwards in all directions (3 dimensions), as opposed to your belief that it is merely adjacent to the direction that light is entering from.

You see, a gravity well is a 3 dimensional "Vortex" of varying levels of gravitational gradients, and actually extends out into space, pretty much to infinity, with its strength decreasing in inverse proportion to the square of the distance.

Which means, that even as the light *APPROACHES* the sun, it is ALREADY having its course altered.

Your belief that the photon is not significantly altered in its course until it gets "tangential" to the star completely ignores the actual mechanics of the inverse square law that describes a gravitational gradient.

Gravity does not produce a "Sharp" line of "Things alter course" and "Then things Don't", because the effects of gravitation are additive with distance traveled.

Every photon that passes through a gravity well will have its course altered toward the gravity well of that star, something that your simplistic (not a bad thing) and totally ignorant drawing completely ignores is the effects of the gravity well that is encountered BEFORE the photon passes beside the Sun.

This also happens to be where measurements of parallax are taken

Yes, measurements of parallax are taken WITHIN the gravity well, as in, the photon has already passed through HALF of the gravity well.

And thus, the photon has ALREADY altered its course by the time it has even reached our planets orbit.

Is it altered as much off course as it would be if we had measured it AFTER it had passed through the entire gravity well?

No, of course not... but to claim that it is NOT altered in its course is to completely IGNORE the laws of physics that you claim to be "Parroting"

thus, such measurements are taken before the effect of lensing occurs.

Which is why this statement is ignorant.

We measure parallax at each blue dot. This is before any significant lensing has occurred.

You used the word "Significant" in that sentance incorrectly.

You should probably brush up on your definitions of the terms you use, before you spout them off as proof of your "Belief", it might help your argument.

ETA: so you don't have to take my word for it...

Oh, rest assured, I won't.

reply to post by Phage

The use of parallax depends on the comparison of the subtended angles between a near star and a distant star. Since the light of both stars is equally affected by gravity at any point of Earth's orbit, the effects of gravity are nullified.

So, you are saying that optical effects that change our perspective on distance would not be effected by a lensing effect, because the background stars that we compare the near star to are ALSO lensed....?

Really?

and how exactly do we know how far away those background stars are?

Aren't we seeing them BOTH at the wrong distance?

reply to post by ErtaiNaGia


Dark Matter is no more than a very shaky theory on a slippery slope. There is no explanation for it other than to invent it to make the Universe make more sense to things that we already think we know.

In the coming years, we may find out that this "Dark Matter" was no more than a space filler for inadequacy in our science and math. Check back with me in 25 years.

reply to post by ErtaiNaGia

We don't need to know the distance to the distant stars to use parallax to determine the distance of near stars. The only measurements needed are the length of the baseline (Earth's orbit) and the parallax (the difference in subtended angles between the near star and the distant star). Trigonometry does the rest.

The distance to stars (and other objects) at greater distances than can be determined by parallax is determined by their brightness and their red shift.

Originally posted by Devino
I fail to see how any amount of mass would cement all of the stars in the galaxy together. Most of the galaxy acts like a ridged wheel as though all stars have a physical connection.

No it's not really like it's cemented together. Our sun doesn't even stay in the same spiral arm of the milky way galaxy, it's quite dynamic in that respect.

But I think the subject you raised is explored thoroughly in this paper:

The structure of spiral galaxies: radial profiles in stellar Mass-to-Light ratio and the Dark Matter distribution

The colour and metallicity gradients observed in spiral galaxies suggest that the mass-to-light ratio (M*/L) of the stellar disc is a function of radius. This is indeed predicted by chemo-photometric models of galactic discs.
We investigate the distribution of luminous and dark matter in spiral galaxies, taking into account the radial dependence of the stellar M*/L - which is usually assumed to be constant in studies of the mass structure.
From the chemo-photometric models of Portinari et al. (2004) and in agreement with the observed radial profiles of galaxy colours, we derive the typical average M*/L profile of the stellar discs of spiral galaxies. We compute the corresponding Variable Mass-to-Light (VML) stellar surface density profile and then the VML disc contribution to the circular velocity. We use the latter, combined with a well studied dark matter velocity profile, to mass model the co-added rotation curves of Persic et al. (1996).

They offer plenty of detail and lots of references to other sources with more detail.

Also I thought it was interesting to see this paper claiming the galaxy we live in doesn't seem to need dark matter to explain the rotation:

Missing Milky Way Dark Matter

a new study aimed at detecting the Milky Way’s dark disk have come up empty....

Using estimations on the mass from the visible stars and the interstellar medium, the team compared this visible mass to the solution for mass from the observations of the kinematics to search for a discrepancy indicative of dark matter. When the comparison was made, the team discovered that, “[t]he agreement between the visible mass and our dynamical solution is striking, and there is no need to invoke any dark component.”

However observing the milky way is kind of like trying to see the forest through the trees, there's a reason for that expression so I'm not sure how much weight to give this study.

Actually there are bigger problems with observations not matching visible observations of baryonic matter than galaxy rotation like the paper I posted on page 2 relating to the bullet cluster, so I'm not even getting too hung up on galaxy rotation as the main problem, though you're right, that's where dark matter got its start. I don't think that's the biggest dark matter problem today though.

Originally posted by Arbitrageur

Originally posted by Devino
I fail to see how any amount of mass would cement all of the stars in the galaxy together. Most of the galaxy acts like a ridged wheel as though all stars have a physical connection.

No it's not really like it's cemented together.

Are you contradicting me now? I'm the one who told Devino that dark matter effectively cemented the matter of a galaxy together. Of course, I didn't mean it literally... it was for illustrative purposes only. Thank you for explaining it in more detail, though. Sometimes, even I get detail fatigue (no matter how much I enjoy explaining things).

reply to post by ErtaiNaGia


Are you forgetting that, when the light reaches the Earth, the Earth is in the gravitational potential with it? We are being "warped" just as the light is. We can only measure the deflection of the light from outside the denser gravitational potential - that is, after the light passes the points where we make measurements of parallax.
I do apologize for knowing what I'm talking about. The more involved details of General Relativity can be lost even on many physicists, but they are non-negotiable... and I'm not the one who doesn't understand.

reply to post by CLPrime

Are you forgetting that, when the light reaches the Earth, the Earth is in the gravitational potential with it?

HAHAHAHAHAHA.... No.

We are being "warped" just as the light is.

Oh, by all means... explain what you think that means...

Go ahead, I'm breathless with anticipation.

We can only measure the deflection of the light from outside the denser gravitational potential

And it is clear that you have no Idea what you are talking about.

Honestly... this conversation with you is getting kinda sad.

that is, after the light passes the points where we make measurements of parallax.

Dude... seriously, you are just over-reaching now.

I do apologize for knowing what I'm talking about.

No, you see, you should be apologizing for NOT knowing that you are talking about, because THAT is the problem.

The more involved details of General Relativity can be lost even on many physicists, but they are non-negotiable... and I'm not the one who doesn't understand.

Oh, the good old, "I know you are but what am I?"

You are too funny....

Come back when your ego isn't getting in the way of this conversation.

Seriously.

[atsimg]http://files.abovetopsecret.com/images/member/d68d241c2e5a.jpg[/atsimg]

reply to post by CLPrime

You know, I'll have to defer to your opinion on this matter as I can clearly tell that you know more about this stuff than I do. However I am not understanding how, what you are describing, can take place without the introduction of another force and I don't mean dark matter. I have read your reply several times and there seems to be something missing. It is counter-intuitive to my understanding of orbital mechanics.

I was comparing the orbital characteristics of planets around our Sun, and planets around other stars that have been observed, and moons around a planet to that of stars orbiting the galaxy. In our solar system we see that distance determines orbital times. Our galaxy is acting like a solid mass that is rotating yet it is not solid. From my understanding I see missing energy here that is accelerating the outer stars orbiting the galaxy and gravitational force from the center will not account for this phenomena.

reply to post by Arbitrageur

Thanks for the contribution Arbitrageur, it's always a pleasure discussing these things with you. I must say that even though I appreciate your link, it is beyond my understanding.

The colour and metallicity gradients observed in spiral galaxies suggest that the mass-to-light ratio (M*/L) of the stellar disc is a function of radius.

I'll have to take their word for this since I don't understand what it means. That's OK though since astronomy is not my profession, just one of many interests.

No it's not really like it's cemented together. Our sun doesn't even stay in the same spiral arm of the milky way galaxy, it's quite dynamic in that respect.

I agree but this was in reference to a comment from CLPrime and didn't actually mean that stars were "cemented" or frozen in place. It was rather describing the rigidness of galaxies. I still see this as a phenomena that dark matter can not explain.

The galaxy has many different motions, here are a few and correct me if these are wrong. All of the stars that are outside of the galactic bar orbit once every @225 million years (this is the rigidness that I was referring to). The galactic arms orbit once every @125 million years and the galactic bar once every @50 million years. These also maintain their shape and thus appear rigid. Perhaps you or CLPrime can verify or show otherwise for these motions as I am not so sure of their acuracy.

My point here is in the different speeds of these observed motions. Galactic arms are comprised of stars that are more clustered or compressed together than the areas between arms. The stars are moving slower than the arms so what are these arms then? It is almost as though these galactic arms are a wave of energy that are accelerating the stars around the center. The source of this energy must come from the center as this is where the galactic bar is located and what we see here is a much faster rotation period and much more mass in a much different configuration from the rest of the galaxy. Part of the center bar has what appear to be preformed spiral arms.

Actually there are bigger problems with observations not matching visible observations of baryonic matter than galaxy rotation like the paper I posted on page 2 relating to the bullet cluster, so I'm not even getting too hung up on galaxy rotation as the main problem, though you're right, that's where dark matter got its start. I don't think that's the biggest dark matter problem today though.

If the galactic rotation problem is the creation point for the theory of dark matter and this has been proven to be wrong then what is the porpose of the Dark matter theory? Is it now being used to try and explain other observed phenomena? This sounds like a bad idea going wild.

Originally posted by CLPrime

Are you contradicting me now? I'm the one who told Devino that dark matter effectively cemented the matter of a galaxy together.

I think you already answered your own question, which is that I'm providing more of a detail clarification than a contradiction. As a rough visualization, what you said is not a bad analogy so I don't fault you for using that description, but Devino appeared to me to have been taking it a little too literally.

Originally posted by Devino
You know, I'll have to defer to your opinion on this matter as I can clearly tell that you know more about this stuff than I do. ...

I was comparing the orbital characteristics of planets around our Sun, and planets around other stars that have been observed, and moons around a planet to that of stars orbiting the galaxy.

Yes CLprime does know what he's talking about regarding the topics in this thread, as does Phage.

In the orbital mechanics of our solar system, almost all the mass of our entire solar system is in the Sun, it's something like 99.9%.

To visualize a mass distribution in our solar system more like a galaxy, you'd need to add many solar masses to our solar system so that most of the mass in our solar system was NOT in the center. This is a very different dynamic than the orbital mechanics of our solar system as it is now.

Originally posted by Devino
reply to post by Arbitrageur

 

Thanks for the contribution Arbitrageur, it's always a pleasure discussing these things with you. I must say that even though I appreciate your link, it is beyond my understanding.

Actually that paper has a lot more readable than many, but if it's beyond your understanding, so be it. It does answer your question though.

If the galactic rotation problem is the creation point for the theory of dark matter and this has been proven to be wrong then what is the porpose of the Dark matter theory? Is it now being used to try and explain other observed phenomena? This sounds like a bad idea going wild.

The galactic rotation problem hasn't been proven to be wrong, however there are other plausible explanations besides dark matter, such as the modified gravity theories called MOG and MOND for example. So let's say it's "debatable" because there are alternate explanations, rather than saying it's proven to be wrong.

However, observations in the bullet cluster don't appear so far to be all that debatable, even with alternate theories, and this is not a galactic rotation problem.

Despite all our detailed observations, we are still steeped in ignorance. But the bullet cluster observations are very significant. They make it very difficult to claim, as some people have, that there's a another way to explain what we are seeing without using dark matter. Galactic rotations MIGHT be explained by alternate gravity theories without the use of dark matter, but the bullet cluster observations apparently can't be explained by alternate gravity theories.

Originally posted by XPLodER
reply to post by ErtaiNaGia

 

thank you for the invitation to join the thread

first to answer a few questions
the missing mass in the universe can be accounted for with lensing and optics


NOTE the glass of water is showing a pricipal of optics not just gravitational lenses

the galaxy in question is acting like an optical lens, with the help of gravity
it is a reasonable large galaxy but a single galaxy and the "density" of the galaxy in conjunction with gravity creates the gravitational lense in the diagram.

this is our galaxy, also considered capable of the same "lensing"



an just as in the first diagram the same pricipal applies to our galaxy

there is a mass to image offset that can account for the "displacement" of the observed mass in the universe (location not amount)

What if there was some sort of "Lensing" effect around massive objects like stars... maybe caused by "Gravity" that bent light towards the center of the star system?

i wrote an interesting thread on gravitational microscoping for spheres thats short and to the point

ATS thread gravitational microscoping

so in the example of the first diagram it is the "optical density" not just gravity which provides the "lensing potential"

here is a picture that represents the gravitational microscoping theory

(IMHO)



if you notice in the picture the "image" of a solar system is enlarged and some planets can only be half seen,
this is the magnifaction bias of a density with gravity lense.

in this way the center image is "increased in size and brightness and "presented" on the outter most curved surface of the lense.
this means a great amount of the mass inside the "lense" will be "blocked" from line of sight. as the center "image" has now increased in size Obscuring the less magnifyed area

depending on angle of incidence to object optical density and gravity (and an object at center) the mass not at the focal center so is not magnifyed.




when we see the bullet cluster we are looking at the focal center not the center of mass

it is an expected effect of density/gravity lensing, even more so in a cluster
same density/gravity but optically "microscoped" into an area of just gas and no mass and that image is "presented" (on the outter surface) of the lense for our telescopes to interacte with.




the following diagram shows how mass in hidden in these "lenses"

and this is all done with optical density and gravity.

lenses could be reasonably common






lensing bullet cluster?



so if we look at more diagrams we can see single galaxy lenses "density/gravity lens"



here is an image of a micro scope looking at a glass sphere



if we were to "gravity" to the center of the glass sphere the image would be "what is in the center" of the "center" of the glass sphere not the object behind it

when two lenses interacte with each other strange effects are encountered
one effect is to increase or decrease the area and density of the lense



which can have the effects of
giving objects "apparent" movement
dislocating mass from its "acual" to a"apperant" positions

Now, keep in mind, our knowledge of galactic mass, is based on our estimations of stellar masses, and our observation of their average separation distance.

when the news that voyager might leave the helio sphere earlyer than expected makes me think that the lenses are more powerful than i had initially anticipated an the distence to steller objects would be greatly effected

So, what if the galaxy is actually more dense than we have observed it to be?

as shown in the NASA diagram in the first image the density has an effect on what we see
and this difference in density is very important when trying to weigh the universe.

What if there was some sort of "Lensing" effect around massive objects like stars... maybe caused by "Gravity" that bent light towards the center of the star system?

what you have described is "gravitational microscoping"
i have linked in this reply

But, I believe that this is actually a fairly solid hypothesis that could account for the "Missing Mass" of the galaxy... that being our incorrect calculations of the density of the galaxy, by seeing stars and such as farther away than they actually are.

you would enjoy my universe full of lense shaped bubbles thread
it explains the bases for density/gravity lensing
and the effects of the heliospherical bubble to the distence and location of "apparent" objects

ATS thread here

objects in the mirror are closer than they "appair"
the universe is full of lense shaped bubbles

xploder

edit on 5-7-2011 by XPLodER because: add note

quoting myself because no one in this thread has answered some of the questions raised

to phage
is this described as gravitational lensing but not described or predicted by einstein?
is this an optical density effect?
this IS described as gravitational lensing

to the op the link you have provided is very interesting thank you op


to the A man
you do provide a very good insight to these topics

to devino

hi buddy good to catch up

xploder

reply to post by ErtaiNaGia


It took a couple days to get a response back, but I asked an actual astrophysicist -- Stephen Holland, who works with NASA's Swift Science Center -- about the lensing effect of the sun. This was his response:

"The spacetime curvature around a massive body like the Sun reaches a maximum at the center of the Sun and smoothly decreases as you move away from it. And despite its large (by human scales) mass, the Sun does not generate much curvature so we can only really detect the deflection of light for rays that pass as close to the Sun as possible. That means you want your observed source, the Sun, and the Earth to be roughly in a line. When you do parallax measurements, the rays are roughly tangential to the Earth's orbit, so they don't pass very near the Sun. As a result the deflection is extremely small. If necessary, this effect could be computed and removed but for most measurements it is not likely to be important."

a reply to: ErtaiNaGia

Hey! i know it was a really long time ago, but I want to know if you've made any progress or changes to your theory or ideas in this post! I have similar theory, or at least one that applies. I tried to message you, but it says I can only private message staff or something.

I think if we could see far enough we would see ourselves. It is possible we already do, but due to lensing we are unrecognizable to ourselves. In my opinion the observable universe is a closed loop with the light just funneling around and around. Much of what we see as different galaxies is simply the light being recycled over and over, coming from multiple different timelines of the same galaxies. What light hits us directly, also hits from other various points in the funnel. I would bet that much of what we see isn't really where we see it, and how we see it isn't how it really is..

originally posted by: entr0pi
a reply to: ErtaiNaGia

Hey! i know it was a really long time ago, but I want to know if you've made any progress or changes to your theory or ideas in this post! I have similar theory, or at least one that applies. I tried to message you, but it says I can only private message staff or something.

In the upper left corner of each post (except your own) you can see either a star or a tilde (~). If you see the tilde it means the account has been deleted which means nobody can send a PM to that account.

You probably need a minimum number of posts or something before you can send PMs to anyone.

Hopefully you've familiarized yourself with observational data to see if your idea is consistent with it. ErtaiNaGia's idea was not consistent with observational data, so hopefully your hypothesis isn't too similar, because if it's very similar, it's probably wrong.