Explination for Dark Matter

Dark matter, having been hypothesized to exist to account for the discrepancy between our knowledge of gravitational attraction, and our observation of galactic motion (specifically, the different rotational speeds of stars around the galactic center at a given distance) is our current hypothesis for explaining these discrepancies...

That there is a LARGE amount of massive... well.... matter, that we can't SEE, that is contributing to the mass of galaxies.

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.

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

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?

Would that not change our perspective on the universe, and the distance of stars?

(I have drawn this crude picture to represent what I am talking about)

[atsimg]http://files.abovetopsecret.com/images/member/c32dcfb49db7.jpg[/atsimg]

Now, I have looked for quite some time to see if local gravitational lensing is currently accounted for in astronomical measurements, and despite my Extensive training in Google-Fu, I have been able to find no correlation....

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.

And I'm going to be really disappointed, if astrophysicists have continued to use "Pre-Einsteinian" calculation methods for calculating interstellar distances, despite the fact that we knew about this effect for, what? decades?

Anyways... thoughts? Our our astrophysics calculations ALREADY done with this taken into account?

Anyone?

Anyone?

Bueler?

reply to post by ErtaiNaGia


Why's it gotta be dark...racist

On a more serious note.. I'm not quite sure what your question is

Originally posted by mb2591
reply to post by ErtaiNaGia

 

Why's it gotta be dark...racist

On a more serious note.. I'm not quite sure what your question is

edit on 5-7-2011 by mb2591 because: (no reason given)

LOL!

That's kinda funny... in a sad sort of way.

On a more serious note.. I'm not quite sure what your question is

I didn't have a question.

Originally posted by ErtaiNaGia
Bueler?

edit on 5-7-2011 by ErtaiNaGia because: smaller picture

Has takin the day off
(AGAIN) and left a note that said consider recycled universal matter.

Be well

reply to post by ErtaiNaGia


The kind of lensing you're talking about, no, it hasn't been factored into distance and mass calculations. Astrophysicists know about gravitational lensing, but it's only considering significant around black holes. To introduce a second source of lensing would require a revision of all accepted masses and distances. Though, if such lensing does exist, then it's a revision that must be done.
You're also not the only one here with this idea. I think it's XPLodER who has a similar lensing theory. And, personally, I like the idea.

reply to post by CLPrime

The kind of lensing you're talking about, no, it hasn't been factored into distance and mass calculations.

OOPS!!! LOL

Astrophysicists know about gravitational lensing, but it's only considering significant around black holes.

To introduce a second source of lensing would require a revision of all accepted masses and distances.

Ya, that is my point, actually.

Though, if such lensing does exist, then it's a revision that must be done.

Agreed

You're also not the only one here with this idea. I think it's XPLodER who has a similar lensing theory. And, personally, I like the idea.

Ya, I happened to stumble across some of his posts after I posted this, and did some more digging.
Good stuff!

Gravitational lensing occurs when light which originated beyond a massive object (galaxy, cluster, etc.) passes that object. Light from the galaxy itself is not "bent".
minerva.union.edu...

The effects are readily apparent, producing distorted and multiple images of the galaxy from which the light is being lensed.
www.sciencedaily.com...

Originally posted by Phage
Gravitational lensing occurs when light which originated beyond a massive object (galaxy, cluster, etc.) passes that object. Light from the galaxy itself is not "bent".
minerva.union.edu...

The effects are readily apparent, producing distorted and multiple images of the galaxy from which the light is being lensed.
www.sciencedaily.com...

edit on 7/5/2011 by Phage because: (no reason given)

Thanks Phage....

Did you have... uhm... a comment or something?

I cant seem to figure out why you posted that.

Considering that we aren't even sure of the mass of the Oort cloud around our own solar system, I'd say that they have simply grossly underestimated the amount of ordinary mass through out our galaxy (and even intergalactic space).

Perhaps they've even grossly underestimated the number of planets. My point is that there is so much space in between stars that if they even underestimated the number of normal matter just floating out there by even 1% then that would more than make up for the amount of "missing" mass they've estimated for our galaxy (and the entire Universe).

Hell, it wasn't until just recently (2003-2005) that we discovered additional rings around Uranus.

It's pretty arrogant of us to think that we've "seen it all". 99.9% of what we "know" about our Universe is based on extrapolation of information that we have observed directly. Considering we are missing about 96% of the matter out there, I'd say those extrapolations are simply way off base.

No such thing as dark matter.

reply to post by Cryptonomicon

It's pretty arrogant of us to think that we've "seen it all". 99.9% of what we "know" about our Universe is based on extrapolation of information that we have observed directly. Considering we are missing about 96% of the matter out there, I'd say those extrapolations are simply way off base.

No such thing as dark matter.

Yeah! Exactly!

Thank you for that post!

reply to post by ErtaiNaGia

I posted it to show that the effects of gravitational lensing are well understood and unless every galaxy observed is to be precisely located "behind" a large mass in order to produce an "enlarged" image, their sizes are not being incorrectly calculated.

reply to post by Phage

I posted it to show that the effects of gravitational lensing are well understood and unless every galaxy observed is to be precisely located "behind" a large mass in order to produce an "enlarged" image, their sizes are not being incorrectly calculated.

I'm talking about the gravitational effect of our own Sun.

Not other galaxies.

reply to post by ErtaiNaGia


So, I've had time to go over the idea. First of all, considering the gravitational effects of individual stars, no star is going to "bend" light enough to create any noticeable lensing. This issue pertains, as well, to larger objects, such as solar systems. The only time gravitational lensing becomes significant is with galaxy clusters, and, as Phage explained, such lensing is well-accounted for. But, even then, the effect is relatively minor. Black holes, as I said, do a great job of lensing, creating multiple images of objects behind them (as do some larger clusters).

Light is not lensed by the object it is released from, as it follows a path antiparallel to the gravitational field. So, an object cannot be responsible for lensing its own light.

And we can eliminate any other sources of lensing by considering their effects on light (akin to the problems with the "tired light" hypothesis). We can also discard any variation in the speed of light caused by such lensing, as the restraints of the Ampere-Maxwell Law demand that light travel at a very specific velocity - otherwise, it is unable to sustain itself, and the EM wave collapses.

Putting all of these together (considering them in detail, not just by how I've summarized them here) can effectively eliminate all sources of lensing from being responsible for altering our view of the matter distribution of the universe.

The Sun has far too little mass to produce such an effect but as I pointed out, only the light passing directly by the Sun (or other massive object) on its way to Earth is affected perceptibly. Only galaxies on the dayside of Earth would have any chance of being affected and only when they were directly opposite the Sun. If this were not the case all of the stars in the sky would be "displaced" by the Sun's gravity, depending on the season.

planetarium.lambuth.edu...

Originally posted by Phage
The Sun has far too little mass to produce such an effect

This is not actually acurate.

Technicaly (and I think you'll agree with me) mass distorts space time (ala, Einstein's General relativity), no matter the AMOUNT of mass, actually.

It just does not really become noticable until the mass becomes insainly large, or the distance of the photon approaches the center of mass of the massive object.

I happened to run across a basic equation that describes the angle that a photon is altered as a function of the objects mass, the distance the photon is from the center of the object, the gravitational constant of the universe, and the speed of light.

Here is that Equation:

Off Angle = (4*g*M)/r*(c^2)

g = 0.0000000000667 (gravitational constant)
M = mass in kilograms (THE SUN: 1,988,920,000,000,000,000,000,000,000,000)
r = radius in meters (one AU: 149,598,000,000)
c^2 = 89,875,517,900,000,000

So, I plugged this one into Google's handy dandy calculator equation, and I got this:

0.0000000394671664 degrees, which is 0.000142081799 arc seconds

I say this because a parsec (astronomical unit of measurement) is the parallax of one arc second.

Now, the difference that this could make, would not seem like much, but it actually would be quite huge....

Because the parallax of one arc second, is a measurement of some 4.3 light years.

So, being off by one ten-thousandth, would put your star several solar radii distance closer than you originally calculated.

And when you get into measurements of Kiloparsecs, Megaparsecs, and such, this can REALLY add up

but as I pointed out, only the light passing directly by the Sun (or other massive object) on its way to Earth is affected perceptibly.

Perceptibly for humans, yes... but we measure astronomical distances in mega-parsecs... and most of our calculations on universal expansion are based upon the accuracy of these measurements.

This means that the further an object is from the sun, the more important the gravitational lensing effect will be, until you get objects that are SO distant, that the gravitational lensing effect is constituting the BULK of the parallax angle measurement.

Only galaxies on the dayside of Earth would have any chance of being affected and only when they were directly opposite the Sun.

No, this is not true either, you are assuming that gravity has a definite cut off distance to interact with light, and this is not the case.

If this were not the case all of the stars in the sky would be "displaced" by the Sun's gravity, depending on the season.

The displacement would effect objects that are off axis from our orbit MORE than objects that are on axis to our orbit... due to the distance off center the light would be traveling.

So, polar measurements (looking solar north and south) would be affected more.

reply to post by ErtaiNaGia

I don’t think a galaxy can cause a gravitational lensing effect on its own light. perhaps a group of galaxies could do this to one, but how come all galaxies observed show this rotational continuity?

The odd thing about this idea of dark matter is that the inverse square law does not change. The further from the center of a galaxy the less gravitational force there is from the center and the slower an orbiting object will be. It does not matter how much material we put into this galaxy it will still remain as such, inversely proportionate to the square of the distance.

I have never been able to understand how, from this observation, the theory of dark matter was born. I don’t see any missing mass, just a misunderstanding of galactic motion using a gravity only theory.

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

reply to post by Devino

I don’t think a galaxy can cause a gravitational lensing effect on its own light.

No, I was talking about a star, or galaxy causing gravitational lensing of light that is coming from outside itself.

Because we are *IN* the gravitational well of our sun, and our galaxy.

Look at the picture I posted in the OP....

The orange dot at the bottom is our sun... the blue dot is the earth, and the orange dot at the top is another star.

and the big yellow circle surrounding our sun, is the gravitational well of our star.

reply to post by ErtaiNaGia

I read the discussion between you and Phage. I see you’re using our Sun as the object causing the gravitational lensing effect. I don’t see how this would be significant nor how it could effect the observation from the night time sky.

This means that the further an object is from the sun, the more important the gravitational lensing effect will be, until you get objects that are SO distant, that the gravitational lensing effect is constituting the BULK of the parallax angle measurement.

This only works from the point of the gravitational lensing effect and beyond. It has nothing to do with the distance of the object to our Sun.

you are assuming that gravity has a definite cut off distance to interact with light, and this is not the case.

Gravity follows the inverse square law. It is effected by the mass of an object and the distance between two masses. Figure out the radius of our Sun and its gravitational force and inversely square that force by the distance to Earth. This, I think, will show an insignificant amount of force to create a gravitational lensing effect as seen from Earth in the night sky (looking away from the Sun).

Originally posted by ErtaiNaGia

So, I plugged this one into Google's handy dandy calculator equation, and I got this:

0.0000000394671664 degrees, which is 0.000142081799 arc seconds

I say this because a parsec (astronomical unit of measurement) is the parallax of one arc second.

Now, the difference that this could make, would not seem like much, but it actually would be quite huge....

Because the parallax of one arc second, is a measurement of some 4.3 light years.

So, being off by one ten-thousandth, would put your star several solar radii distance closer than you originally calculated.

And when you get into measurements of Kiloparsecs, Megaparsecs, and such, this can REALLY add up

If parallax was used for such vast distances. Parallax distancing is currently only possible out to about 1600 light-years... which is less than 500 parsecs (because a parsec is about 3.26 light-years).

Also, the answer is in radians, not degrees. So: 3.9494*10^-8 radians = 2.262846*10^-6 degrees = 0.008146246 arcseconds.
According to your calculation, this is the angular deflection of light passing at 1 AU from the sun. So, this represents how much the light from an object as been bent toward the sun... meaning, it's how much the whole object has been visually shifted in the sky. Over the course of 6 months, this would take 0.0162925 arseconds off the measurement of a given star's parallax. This equates to about 60 parsecs (1/0.0162925), which would, admittedly, become very significant for stars within a few hundred parsecs (which would include every star we measure the distance of using parallax - as I said above, out to 500 parsecs).

But, now, consider how this parallax measurement is being taken... at the point where the light from the star would be passing the sun to be affected by its gravitational lensing. Our measurement of the light is made before it gets deflected. Therefore, the very nature of our parallax measurements remove the effect of gravitational lensing from those measurements.