Thoughts On Dark Matter

[TheoreticalCheckmate]

It can't be detected but we see the effects of it. Could dark matter just be space? What if what we perceive as empty space is actually a space filled with dark matter and dark energy? After all , we really don't know what's outside the universe.

[mathematic]

Dark energy seems to be uniformly distributed in space. Dark matter has a diatribution that has been detected around galaxies.

[20ny]

Could it be that there is no dark matter out there at all...? Don't get me wrong, I am excited to think that there is the possibility of Dark Matter, but what I understand is that the gravitational pull of stars on the outer rim of our known galaxy are moving faster than what they should be considering the "Rotation Curve". The furthest star on the edge of our known galaxy is ULAS J0015+01 which is 900,000 light years from Earth. Could it be a simple answer that our galaxy had a stronger gravitational pull 900,000 years ago? That the Stars were moving an increased speed 900,000 years ago...? And what we are looking at is just an eco of what the universe speed/gravitational pull once was...?

Edited July 5, 2015 by 20ny

[imatfaal]

Could it be that there is no dark matter out there at all...? Don't get me wrong, I am excited to think that there is the possibility of Dark Matter, but what I understand is that the gravitational pull of stars on the outer rim of our known galaxy are moving faster than what they should be considering the "Rotation Curve". The furthest star on the edge of our known galaxy is ULAS J0015+01 which is 900,000 light years from Earth. Could it be a simple answer that our galaxy had a stronger gravitational pull 900,000 years ago? That the Stars were moving an increased speed 900,000 years ago...? And what we are looking at is just an eco of what the universe speed/gravitational pull once was...?

 

1. The same logic we use to propose the existence of dark matter also applies to other galaxies which may be larger or smaller; which would make the correlation of age to gravitational strength very difficult if not impossible. More importantly these galaxies are much greater distances away from us - thus they should obey the same rules about age/gravity from millions, tens and hundreds of millions of years. Do you see how you simple solution rapidly becomes more complicated? The simplest solution we can come up with is dark matter

 

2. Everything becomes much more difficult if the laws of physics vary with time - ie almost all of our fundamental rules would have to be thought of as temporary approximations. Conservation of Energy is intimately linked with symmetry in time.

 

3. We have evidence of dark matter that does not rely on the rotation curves. Gravitational lensing shows the distribution of dark matter and exceptional circumstances like the bullet cluster demonstrate the predicted difference between normally interacting matter and gravity-only interaction dark matter

[20ny]

Thank you very much for explaining that to me... It is very exciting to think about the possibilities of dark matter and dark energy.

[imatfaal]

Thank you very much for explaining that to me... It is very exciting to think about the possibilities of dark matter and dark energy.

 

Completely agree. The ability to predict the existence of a particle and then wait for years whilst the world of science finds a way to isolate and test it is an amazing triumph of the human mind and imagination.

 

I think it was Frank Close I heard talking about this point and that theory is so far advanced of technology that very soon predicted particles (no matter how well accepted in theoretical circles and how well searched for) will not be able to be found in the hypothesizer's lifetime

[J.C.MacSwell]

Briefly speaking, we believe we know: (feel free to comment, correct or add)

 

1. the mass distribution from the radiation signals we receive (could we be underestimating the mass?)

2. The distances involved from the overall redshift (could we be overestimating the distance, and thus the diameters?)

3. the rotational speeds involved from the frequency shifts of the above radiation at different orbit diameters

 

Also, if space is not Euclidean at astronomical distances we could overestimate the diameters even if we get the distance correct.

 

Not suggesting I think it is wrong, just wonder how confident we are in the estimates.

Edited July 5, 2015 by J.C.MacSwell

[imatfaal]

Briefly speaking, we believe we know: (feel free to comment, correct or add)

 

1. the mass distribution from the radiation signals we receive (could we be underestimating the mass?)

2. The distances involved from the overall redshift (could we be overestimating the distance, and thus the diameters?)

3. the rotational speeds involved from the frequency shifts of the above radiation at different orbit diameters

 

Also, if space is not Euclidean at astronomical distances we could overestimate the diameters even if we get the distance correct.

 

Not suggesting I think it is wrong, just wonder how confident we are in the estimates.

 

1. If we were underestimating the amount of baryonic matter and thus inferring a non-existent dark matter then we would still have to find an explanation of the Bullet Cluster, of the Filaments of something in the large structure which bend the light, and the fact that the matter would have to be unusually distributed to have the same effects (ie it couldn't be where we think it must be without bumping into itself and glowing).

2. This would go to the root of modern cosmology - I do not have the knowledge to explain where the contradictions would arise but I am pretty sure that all of our present models would fail. The evidence of the Type iia supernovae backups the red-shift idea and gets stronger and stronger with every new observation.

 

Planck tends to make us sure - at anything less than the largest distances which are beyond our measurement capabilities - that the universe is flat.

 

Also your point 2 makes me think of Father Ted

 

[J.C.MacSwell]

 

1. If we were underestimating the amount of baryonic matter and thus inferring a non-existent dark matter then we would still have to find an explanation of the Bullet Cluster, of the Filaments of something in the large structure which bend the light, and the fact that the matter would have to be unusually distributed to have the same effects (ie it couldn't be where we think it must be without bumping into itself and glowing).

2. This would go to the root of modern cosmology - I do not have the knowledge to explain where the contradictions would arise but I am pretty sure that all of our present models would fail. The evidence of the Type iia supernovae backups the red-shift idea and gets stronger and stronger with every new observation.

 

Planck tends to make us sure - at anything less than the largest distances which are beyond our measurement capabilities - that the universe is flat.

 

Also your point 2 makes me think of Father Ted

 

Ok. Lets take Father Ted et al (al being the experts) word for it for now on point 2.

 

On your reply to point 1, where is the dark matter distributed or required?

[imatfaal]

The missing matter is - according to our calculations - mainly in halos around the galaxy rather than homogeneous throughout the galactic disc.

 

If we could posit that all the mass was in the middle then we might imagine that the huge light from the active galactic centre and the maelstrom around the blackhole might mask our ability to find the missing matter. But using our ideas of orbital mechanics we cannot find a solution for the rotation curves which fits with added (but for some reason invisible to us) matter solely in the disc - the added mass must be, in the main, around the outside of the disc. But normal matter - without stars blinding us - in a halo around the galaxy should bump into itself and some of its energy would be dispersed as heat and light it would also act as a blanket absorbing some of the enormous amount of radiation; in both these circumstances it would glow.

[J.C.MacSwell]

The missing matter is - according to our calculations - mainly in halos around the galaxy rather than homogeneous throughout the galactic disc.

 

If we could posit that all the mass was in the middle then we might imagine that the huge light from the active galactic centre and the maelstrom around the blackhole might mask our ability to find the missing matter. But using our ideas of orbital mechanics we cannot find a solution for the rotation curves which fits with added (but for some reason invisible to us) matter solely in the disc - the added mass must be, in the main, around the outside of the disc. But normal matter - without stars blinding us - in a halo around the galaxy should bump into itself and some of its energy would be dispersed as heat and light it would also act as a blanket absorbing some of the enormous amount of radiation; in both these circumstances it would glow.

Thanks

This is something I don't picture well.

Why would a halo encourage higher rotation speeds?

I would have expected the extra mass being required inside the orbits of the stars that have the higher than expected orbital speeds.

Is the dark matter at higher speed dragging everything around?

Edited July 7, 2015 by J.C.MacSwell

[hodge]

Perhaps dark matter is not matter. The rotation curve and bending light data could equally or better modeled as a negative gravitational force outward from the center of spiral galaxies (only - not elliptical galaxies). Better yet a model with an aether originating at the center of spiral galaxies whose intensity slope directs matter. Wait a bit. An aether that direcs matter sound like general relativity (GR) model of "space" (originally called a "gravitational aether"). All that would be needed would be the source at the center of spiral galaxies and not in elliptical galaxies. Matter decreases the density of the "gravitational aether" and the aether bends light like in GR.

[Strange]

Perhaps dark matter is not matter.

 

Perhaps.

 

The rotation curve and bending light data could equally or better modeled as a negative gravitational force outward from the center of spiral galaxies (only - not elliptical galaxies). Better yet a model with an aether originating at the center of spiral galaxies whose intensity slope directs matter. Wait a bit. An aether that direcs matter sound like general relativity (GR) model of "space" (originally called a "gravitational aether"). All that would be needed would be the source at the center of spiral galaxies and not in elliptical galaxies. Matter decreases the density of the "gravitational aether" and the aether bends light like in GR.

 

As far as I know, modified gravity theories like this have failed to successfully predict the observed behaviour of galaxies or galaxy clusters.

 

Do you have a better model, or just vague speculation?

[EdEarl]

Phys.org:

Scientist suggests possible link between primordial black holes and dark matter

Dark matter is a mysterious substance composing most of the material universe, now widely thought to be some form of massive exotic particle. An intriguing alternative view is that dark matter is made of black holes formed during the first second of our universe's existence, known as primordial black holes. Now a scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, suggests that this interpretation aligns with our knowledge of cosmic infrared and X-ray background glows and may explain the unexpectedly high masses of merging black holes detected last year.

"This study is an effort to bring together a broad set of ideas and observations to test how well they fit, and the fit is surprisingly good," said Alexander Kashlinsky, an astrophysicist at NASA Goddard. "If this is correct, then all galaxies, including our own, are embedded within a vast sphere of black holes each about 30 times the sun's mass."

I thought black holes had been excluded as an explanation of black holes, but maybe not.

[Markus Hanke]

While I do not advocate any particular alternative of GR over another, in this context I thought it appropriate to mention that there is a class of bimetric theories of gravity which closely mimic weakly interacting dark matter effects, without requiring any new particles ( which would need to fit neatly into the Standard Model, with all associated difficulties ). One example - among others - is Sabine Hossenfelder's proposal :

 

https://www.researchgate.net/publication/235472718_Bimetric_theory_with_exchange_symmetry

 

This is of course all conjecture, but IMHO does warrant further study.

[EdEarl]

Correction: I thought black holes had been excluded as an explanation of dark matter, but maybe not.

[Demolition Guy]

Is it possible that the decomposition of dark matter could produce time and 'light' matter?

[Strange]

Is it possible that the decomposition of dark matter could produce time and 'light' matter?

 

 

I am not aware of any models where dark matter can decay into normal matter (but that doesn't mean there aren't any). There are some models where dark matter can annihilate to produce photons.

 

What do you mean by producing time? Time is a dimension.

[Demolition Guy]

an item of infinite mass would have to exist in a 'non time existent' dimension. As with black holes dragging time in, the decay or release of energy and matter from the reverse process would emit time. this would make time a kind of dimensional radiation. If there is a large amount of dark matter in the universe it would exist in a static dimension 'invisible' to us against the backdrop of time. Is it possible we are just the visible flotsam of a much larger more comprehensive dimension not bound by the laws of time?

[Mordred]

Time isn't a substance that can be dragged in

[Strange]

And there are no items of infinite mass. The rest makes equally little sense.

[LaurieAG]

While we're thinking about dark matter, I always find it interesting that our total calculated matter, dark matter + ordinary matter, equals our ordinary matter times [latex]2 \pi[/latex] within the error bars of our observations. Call it numerology if you like but I think it's an interesting property, especially on a universal scale, as no other constants are involved.

 

https://en.wikipedia.org/wiki/Numerology#To_describe_questionable_concepts_based_on_possibly_coincidental_numerical_patterns

 

The best known example of "numerology" in science involves the coincidental resemblance of certain large numbers that intrigued such eminent men as mathematical physicistPaul Dirac, mathematician Hermann Weyl and astronomer Arthur Stanley Eddington. These numerical coincidences refer to such quantities as the ratio of the age of the universe to the atomic unit of time, the number of electrons in the universe, and the difference in strengths between gravity and the electric force for the electron and proton. ("Is the Universe Fine Tuned for Us?", Stenger, V.J., page 3^[13]).

The discovery of atomic triads (dealing with elements primarily in the same group or column of the periodic table) was considered a form of numerology, and yet ultimately led to the construction of the periodic table. Here the atomic weight of the lightest element and the heaviest are summed, and averaged, and the average is found to be very close to that of the intermediate weight element. This didn't work with every triplet in the same group, but worked often enough to allow later workers to create generalizations. SeeDöbereiner's triads

Large number co-incidences continue to fascinate many mathematical physicists. For instance, James G. Gilson has constructed a "Quantum Theory of Gravity" based loosely on Dirac's large number hypothesis.^[14]

Wolfgang Pauli was also fascinated by the appearance of certain numbers, including 137, in physics.^[15] British mathematician I. J. Good wrote:

 

There have been a few examples of numerology that have led to theories that transformed society: see the mention of Kirchhoff and Balmer in Good (1962, p. 316) ... and one can well include Kepler on account of his third law. It would be fair enough to say that numerology was the origin of the theories of electromagnetism, quantum mechanics, gravitation.... So I intend no disparagement when I describe a formula as numerological. When a numerological formula is proposed, then we may ask whether it is correct. ... I think an appropriate definition of correctness is that the formula has a good explanation, in a Platonic sense, that is, the explanation could be based on a good theory that is not yet known but ‘exists’ in the universe of possible reasonable ideas.

 

— I. J. Good^[16]

 

[steveupson]

While we're thinking about dark matter, I always find it interesting that our total calculated matter, dark matter + ordinary matter, equals our ordinary matter times [latex]2 \pi[/latex] within the error bars of our observations.

 

There's a possible explanation for that geometric relationship. If our understanding of direction in spacetime is superficial, if there is a deeper way to view it, then that would account for that particular relationship rather neatly.

 

I think that this can be proven mathematically, but I need help with the algebra. No one seems to take any stock in mathematical models prepared with mathematical modeling software. A pencil and paper have been recommended as the proper way to go about proving this out.

[Strange]

No one seems to take any stock in mathematical models prepared with mathematical modeling software.

 

 

That is not true. You just expect people to spend their time reverse engineering an animation for you. There is no reason for anyone to do that. I suggest you give people an incentive to do this: money.

[steveupson]

 

 

That is not true. You just expect people to spend their time reverse engineering an animation for you. There is no reason for anyone to do that. I suggest you give people an incentive to do this: money.

 

I've moved on, as instructed by the moderation staff here. Why are you reintroducing a topic that I was explicitly told not to reintroduce? Why not respond to what I actually said?