Jump to content

Dark Matter ?


interested

Recommended Posts

13 hours ago, Strange said:

It can't be baryonic because if it were, it would interact with electromagnetic radiation.

Photons are part of the electromagnetic spectrum, Gravitational lensing of photons is observed in the Bullet Cluster, and is evidence for dark matter.

wikipedia says it best 

--------------------------------------------------------------

Nearly all matter that may be encountered or experienced in everyday life is baryonic matter, which includes atoms of any sort, and provides those with the property of mass. Non-baryonic matter, as implied by the name, is any sort of matter that is not composed primarily of baryons. This might include neutrinos and free electrons, dark matter, such as supersymmetric particles, axions, and black holes.

The very existence of baryons is also a significant issue in cosmology, because it is assumed that the Big Bang produced a state with equal amounts of baryons and antibaryons. The process by which baryons came to outnumber their antiparticles is called baryogenesis.

-------------------------------------------------------------------------

In the observed universe there does not appear to be equal amounts of antimatter, suggesting something is wrong with big bang theory perhaps. Would a black hole disintegrating produce equal amounts of matter and antimatter? Loop quantum gravity allows this to happen.

14 hours ago, beecee said:

I don't see it as baryonic in nature at all, and I havn't the foggiest idea what it could be!

We maybe getting off topic, but DM despite reasonable evidence supporting that concept, is still debatable among our professionals and of course GR is not a final theory. That's science.

 

 

ps: Apologies re the "off topic" remark...I'm getting this DM thread confused with the other DM thread that seems to be producing matter via gravity. :) 

I get payed to think at work about things that are not very interesting to me. In my private unpaid time I like to think about things that interest me, regardless of what a professional says I am allowed to think, especially when they cant make up their mind.

 

Link to comment
Share on other sites

4 minutes ago, interested said:

Photons are part of the electromagnetic spectrum, Gravitational lensing of photons is observed in the Bullet Cluster, and is evidence for dark matter.

Huh? While obviously true, I don't know what the relevance of that is. 

5 minutes ago, interested said:

In the observed universe there does not appear to be equal amounts of antimatter, suggesting something is wrong with big bang theory perhaps.

Not wrong, necessarily. Just incomplete. 

6 minutes ago, interested said:

Would a black hole disintegrating produce equal amounts of matter and antimatter?

Black holes don't disintegrate.

Quote

Loop quantum gravity allows this to happen.

Does it? Can you provide a reference?

But if it does, then it will answer your previous question, in which case I don't know why you asked.

 

Link to comment
Share on other sites

25 minutes ago, interested said:

I get payed to think at work about things that are not very interesting to me. In my private unpaid time I like to think about things that interest me, regardless of what a professional says I am allowed to think, especially when they cant make up their mind.

As a retired old bastard, I also have plenty of time to think, and the first step in thinking is being familiar with the current incumbent models and the empirical evidence that validates them, along of course with any inconsistencies. The second step is to research the interpretations by our professionals and experts and the reasons for that. Third step is to agree that general musings by the likes of you and me, on public science forums, open to any Tom, Dick or Harry, while being fun and sometimes a vehicle for learning, is really highly unlikely to be correct if it disagrees with the generally held incumbent model. And finally the fourth step is to recognise that professional cosmologists never take anything for certain, and are continually researching and amending models and theories as new empirical evidence comes to light.Hence the additions of DE and DM.

Edited by beecee
Link to comment
Share on other sites

1 minute ago, beecee said:

As a retired old bastard, I also have plenty of time to think, and the first step in thinking is being familiar with the current incumbent models and the empirical evidence that validates them, along of course with any inconsistencies. The second step is to research the interpretations by our professionals and experts and the reasons for that. Third step is to agree that general musings by the likes of you and me, on public science forums, open to any Tom, Dick or Harry, while being fun and ssometimes a vehicle for learning, is really highly unlikely to be correct if it disagrees with the generally held incumbent model. And finally the fourth step is to recognise that professional cosmologists never take anything for certain, and are continually researching and amending models and theories as new impirical evidence comes to light.Hence the additions of DE and DM.

Yes I agree, (parentage not included), but not having to be over rigorous we can look at all the theories on the menu, and think about each one, to see if it is believable or not. For me GR is a good theoretical fit, until it goes into singularities, this includes the big bang singularity concept. Loop Quantum gravity, and many other theories on the menu address the nonsense (to me) concept of singularities and infinite gravity. Dark matter is not necessary on all the alternative theories on the menu, and may be the result of stretching the existing theories too far as I suspect is the case with singularities. 

The point is dark matter may not be as abundant as perceived from GR, and as you have pointed out with examples something is causing gravitational lensing which may be a level of dark matter.  

Regards not being completely correct on a subject, it is better to have an opinion on a subject which is partly correct than no idea at all. At the end of the day theories develop and move on, so why just study old theories when newer more interesting and sometimes more believable ones come to the fore, to be discussed by old farts trying to support the unbelievable big bang and a beginning of time theory. 

43 minutes ago, Strange said:

Huh? While obviously true, I don't know what the relevance of that is. 

Not wrong, necessarily. Just incomplete. 

Black holes don't disintegrate.

Does it? Can you provide a reference?

But if it does, then it will answer your previous question, in which case I don't know why you asked.

 

see the other threads I posted on and links already posted.

Link to comment
Share on other sites

On 10/29/2017 at 9:55 PM, interested said:

Yes I agree, (parentage not included), but not having to be over rigorous we can look at all the theories on the menu, and think about each one, to see if it is believable or not. For me GR is a good theoretical fit, until it goes into singularities, this includes the big bang singularity concept. Loop Quantum gravity, and many other theories on the menu address the nonsense (to me) concept of singularities and infinite gravity. Dark matter is not necessary on all the alternative theories on the menu, and may be the result of stretching the existing theories too far as I suspect is the case with singularities. 

Claiming myself as an old bastard is irreverent Aussie slang... :) GR of course is overwhelmingly supported, as it so far matches observational data and has its predictions continually being validated. No theory as yet is all encompassing and the singularity aspect is simply marking the boundaries in which GR is applicable. By the way, most cosmologists do not accept the mathematical singularity leading to infinite concepts.                                     Again DM is evidenced and is the reason why the difficult search for it goes on.

 

Quote

The point is dark matter may not be as abundant as perceived from GR, and as you have pointed out with examples something is causing gravitational lensing which may be a level of dark matter.  

I found this today......https://phys.org/news/2017-11-physicists-dark-strategy.html                   Physicists from Brown University have devised a new strategy for directly detecting dark matter, the elusive material thought to account for the majority of matter in the universe.

Read more at: https://phys.org/news/2017-11-physicists-dark-strategy.html#jCp

:::::::::::::::::::::::::::::::::::::::::::

the paper:

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.119.181303                                     Dark Matter Detection Using Helium Evaporation and Field Ionization                                         

ABSTRACT

We describe a method for dark matter detection based on the evaporation of helium atoms from a cold surface and their subsequent detection using field ionization. When a dark matter particle scatters off a nucleus of the target material, elementary excitations (phonons or rotons) are produced. Excitations which have an energy greater than the binding energy of helium to the surface can result in the evaporation of helium atoms. We propose to detect these atoms by ionizing them in a strong electric field. Because the binding energy of helium to surfaces can be below 1 meV, this detection scheme opens up new possibilities for the detection of dark matter particles in a mass range down to 1MeV/c2.

""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

Quote

Regards not being completely correct on a subject, it is better to have an opinion on a subject which is partly correct than no idea at all. At the end of the day theories develop and move on, so why just study old theories when newer more interesting and sometimes more believable ones come to the fore, to be discussed by old farts trying to support the unbelievable big bang and a beginning of time theory. 

yes, newer hypothesis are surfacing every day; that's science...that's the scientific methodology, and when a hypothesis surfaces that describes what we observe better then the BB theory, then that will be taken on board and the BB theory discarded. But as yet the BB stands unchallenged as the prevailing explanation for the evolution of the universe/space/time from a hotter denser state, starting at t+10-43 seconds. In fact I have been informed by an astronomer acquaintance  of mine, that when a validated QGT is formulated, it will most likely encompass the BB theory and simply extend the parameters beyond that t+10-43 seconds. And of course any theory, such as the BB and the evolution of life all gain in certainty as they continue to align with observation and make successful predictions.

 

 

 

Edited by beecee
Link to comment
Share on other sites

Thanks beecee for the excellent info, to "simply extend the parameters beyond that t+10-43 seconds" is what some theories already do, and do not need quite so much dark matter.The following unrelated link came into my email this morning, the search for WIMPS goes on. 

"The major theoretical model attributes dark matter to weakly interacting massive particles (WIMPs), whose nature is predicted by various high energy physics models," said Torii. "In these models, a WIMP would be its own antiparticle and, when two of them get together, they annihilate, producing known particles like electron/positron pairs, proton/anti-proton pairs, and gamma rays."

Read more at: https://phys.org/news/2015-11-dark-particle-space.html#jCp

------------------------------------------------------------------------------------------------------------------------------------------------------------------------

My earlier suggestion ref dark matter possibly being matter antimatter particles was not a bad guess after all, OR at least I am not the only one who thought it. 

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Questions requiring speculative answers. 

Dark ENERGY drives the expansion of the universe could dark MATTER be slowing it down?

What is dark ENERGY? Could it be Quantum fluctuations, Virtual particles or Virtual waves in space?

Could quantum fluctuations be being created by dark energy particles or high energy particles and cause the expansion of the universe ????????????????

Could an elusive Wimp make the space around it expand and not be detected in outer space????? 

Could the dark matter at the centre of a galaxy be mostly already be absorbed by mass in the galaxy and therefore be none detectable, BUT on the outskirts of galaxies it is still being sucked in from an expanding outer space.??

Could CBR be evidence of extremely small wimps annihilating each other, driving the expansion of space, allowing more wimps to come into existence???????????????????

-----------------------------------------------------------------------------------------------------

From the links you have included scientists are now looking for dark matter with energy levels down to 1MeV/c2. This I understand is way above the levels of the energy from CBR. BUT CBR is visible and is approximately uniform through out all of an expanding space, could CBR be evidence for dark matter not big bang???

 

 

 

Edited by interested
read links
Link to comment
Share on other sites

11 minutes ago, interested said:

My earlier suggestion ref dark matter possibly being matter antimatter particles was not a bad guess after all

There is a big difference between that and particles being their own antiparticles. This is true of photons, for example, but they are not "matter antimatter particles".

12 minutes ago, interested said:

Dark ENERGY drives the expansion of the universe could dark MATTER be slowing it down?

Dark energy doesn't drive expansion, it it is the cause of accelerating expansion.

All matter (including dark matter) was slowing it down until about 5 billion years ago the dark energy came to dominate.

14 minutes ago, interested said:

Could CBR be evidence of extremely small wimps annihilating each other

No. It would have a different spectrum.

Link to comment
Share on other sites

You might be interested in this article about (negative) results that rule out some possibilities: https://physics.aps.org/articles/v10/119

Short version: we [still] don't know.

And here is one that gives a clear view of how dark matter particles behave: https://www.forbes.com/sites/startswithabang/2017/11/02/what-would-happen-if-you-became-dark-matter/#1d72f94f3fd2

Link to comment
Share on other sites

8 hours ago, interested said:

Thanks beecee for the excellent info, to "simply extend the parameters beyond that t+10-43 seconds" is what some theories already do, and do not need quite so much dark matter.The following unrelated link came into my email this morning, the search for WIMPS goes on. 

No probs.....There are many QGTs out there, but the problem is that we are as yet unable to observe at the quantum/Planck level to validate them....string and its many derivatives including LQG, which is why when I mention a QGT I will generally refer to a  validated QGT

That appears to be the stumbling block at this time.

Edited by beecee
Link to comment
Share on other sites

Thanks folks the links induced a googling session, and a bit of summary of what I am thinking.

Starting with the MANTRA everything is quantum fluctuations

The big bang is the source of dark matter, the big bang originates with quantum fluctuations.

Does it matter if dark matter is not matter?

Dark matter does not emit, radiate, or absorb light. FACT

Virtual particles as Quantum fluctuations in space do not emit, radiate, or absorb light and exist on average all the time. FACT.

Once a quantum fluctuation is induced by the movement of a photon in space it will carry on existing for ever unless it encounters another wave in anti-phase cancelling it, or it hits something solid and is absorbed. The Quantum fluctuations in space will therefore on average increase for ever driving the expansion of space. I SEE NO REASON WHY NOT .

Quantum fluctuations could be driving the expansion of space ie are the source of Dark Energy http://www.newsweek.com/new-theory-universe-expansion-quantum-fluctuations-dark-energy-forever-610130  

Could quantum fluctuations existing on average all the time in space be a source of dark matter or is there another viable idea. https://phys.org/news/2011-11-quantum-vacuum-dark.html

Gravity itself may be the result of quantum fluctuations http://www.pbs.org/wgbh/nova/next/physics/gravity-could-be-the-result-of-random-quantum-fluctuations/

 

 

 

 

Edited by interested
Link to comment
Share on other sites

20 minutes ago, interested said:

a quantum fluctuation is induced by the movement of a photon in space

Citation needed.

20 minutes ago, interested said:

Quantum fluctuations could be driving the expansion of space ie are the source of Dark Energy

This thread is about dark matter.

21 minutes ago, interested said:

Could quantum fluctuations existing on average all the time in space be a source of dark matter or is there another viable idea. https://phys.org/news/2011-11-quantum-vacuum-dark.html

From that link: "The idea rests on the hypothesis that particles and antiparticles have gravitational charges of opposite sign."

That is soon to be disproved by the APHA experiment at CERN.

Link to comment
Share on other sites

13 minutes ago, interested said:

Thanks folks the links induced a googling session, and a bit of summary of what I am thinking.

The big bang is the source of dark matter, the big bang originates with quantum fluctuations.

Does it matter if dark matter is not matter?

It's got mass, so I don;t see what other option you have.

13 minutes ago, interested said:

 Quantum fluctuations in space do not emit, radiate, or absorb light and exist on average all the time. FACT.

Nope, not fact. You can add energy to a quantum fluctuation and get photons (i.e. radiate light) 

13 minutes ago, interested said:

Once a quantum fluctuation is induced by the movement of a photon in space it will carry on existing for ever unless it encounters another wave in anti-phase cancelling it, or it hits something solid and is absorbed. The Quantum fluctuations in space will therefore on average increase for ever driving the expansion of space. I SEE NO REASON WHY NOT .

Nope. Maybe learn the physics and you'll see a reason why not.

 

Link to comment
Share on other sites

Just now, Strange said:

Citation needed.

This thread is about dark matter.

From that link: "The idea rests on the hypothesis that particles and antiparticles have gravitational charges of opposite sign."

That is soon to be disproved by the APHA experiment at CERN.

I would of thought wave particle duality would be a sufficient citation or the double slit experiment, but I will see what I can find for you. I have been keeping an eye on Mordreds Thread what space is which has put a few ideas into my head, along these lines.

Yes the thread is about dark matter, but what I was looking at was the quantum fluctuations in space, and reasoning to myself that if a particle is a wave, and a virtual particle is also a wave, both have an equivalent mass then the virtual particles existing on average all the time in space may give an effect of dark matter, if in fact dark matter exists, which it may not.

I did not like the last link, but included it from my googling session, I should have left it out, but included it as it momentarily interested me.

Just now, swansont said:

It's got mass, so I don;t see what other option you have.

Nope, not fact. You can add energy to a quantum fluctuation and get photons (i.e. radiate light) 

Nope. Maybe learn the physics and you'll see a reason why not.

 

Perhaps you could explain 

Edited by interested
Link to comment
Share on other sites

1 hour ago, interested said:

I would of thought wave particle duality would be a sufficient citation or the double slit experiment, but I will see what I can find for you. 

That has nothing to do with virtual particles or the non-zero vacuum energy. (Apart from the fact they are both a consequence of quantum theory.)

1 hour ago, interested said:

Yes the thread is about dark matter, but what I was looking at was the quantum fluctuations in space, and reasoning to myself that if a particle is a wave, and a virtual particle is also a wave, both have an equivalent mass then the virtual particles existing on average all the time in space may give an effect of dark matter, if in fact dark matter exists, which it may not.

I'm sure we have been here before. Virtual particles exist everywhere. Dark matter doesn't.

Link to comment
Share on other sites

15 minutes ago, swansont said:

Start a thread and ask questions on the topic of your choice.

I have another thread in mind when I have done a bit more reading on string theory, but this thread still has some mileage with all the theories people are publishing ref alternative gravity and not needing dark matter. As you must be aware alternative ideas on what dark matter is or is not are plentiful and are interesting to look at and mull over. 

Since this thread is about dark matter, and you have pointed out I do not know what dark matter is or even if it exists in the abundance predicted by the standard models. Perhaps you would like to explain what dark matter is or might be in your opinion. Is Relativity being stretched beyond breaking point, is a new theory on gravity required, etc.

Dark matter does not emit, radiate, or absorb light. It causes galaxies to appear to have more mass than is predicted by current theories on gravity.

empty space does not emit radiate or absorb light either, perhaps there is more to gravity than meets the eye.

Link to comment
Share on other sites

23 minutes ago, interested said:

Since this thread is about dark matter, and you have pointed out I do not know what dark matter is or even if it exists in the abundance predicted by the standard models. Perhaps you would like to explain what dark matter is or might be in your opinion. Is Relativity being stretched beyond breaking point, is a new theory on gravity required, etc.

You keep asking the same questions. The answers are not going to change.

1. No one knows what dark matter is. Although it seems to be a form of matter.

2. So far, no "modified gravity" theories match the observations.

 

Link to comment
Share on other sites

32 minutes ago, Strange said:

You keep asking the same questions. The answers are not going to change.

1. No one knows what dark matter is. Although it seems to be a form of matter.

2. So far, no "modified gravity" theories match the observations.

 

I think Swansont is big enough to answer the question him self, without your assistance.

Ref quantum fluctuations and citations if you google the subject I dont know which link to post for you so I suggest you google it your self

Link to comment
Share on other sites

28 minutes ago, interested said:

I think Swansont is big enough to answer the question him self, without your assistance.

Ref quantum fluctuations and citations if you google the subject I dont know which link to post for you so I suggest you google it your self

Why does it matter who answers? You keep repeating yourself, and the answers are still the same.

What I think dark matter is is of no importance. I don't study gravity or cosmology. I would have no special insight into the problem. 

Link to comment
Share on other sites

4 hours ago, interested said:

Ref quantum fluctuations and citations if you google the subject I dont know which link to post for you so I suggest you google it your self

It is probably quicker, and just as accurate, to just assume you are making stuff up.

Link to comment
Share on other sites

The XMASS collaboration, led by Yoichiro Suzuki at the Kavli IPMU, has reported its latest results on the search for warm dark matter. Their results rule out the possibility that super-weakly interacting massive bosonic particles (bosonic super-WIMPs) constitute all dark matter in the universe

Read more at: https://phys.org/news/2014-10-dark-xmass-editors-physical-letters.html#jCp

 

 

On 11/8/2017 at 0:59 PM, Strange said:

You made the claim that photons cause quantum fluctuations. It is up to you to support your claim (see also: burden of proof).

Photons as you are aware exhibit both wave and particle properties, and they are affected by gravity. They therefore distort space in the same way normal mass does except they are not stationery like a normal particle. Distortions in space are quantum fluctuations. LIGO detected gravitational waves ie distortions in space. Gravitational waves travel at light speed the same as photons except on a bit bigger scale and are omnidirectional. The Graviton if it exists causes a stress field in space towards a mass, if it does not exist, then according to other theories the quantum foam is distorted/absorbed by what ever is passing through it causing a stress field ie the gravitational effect. The dark energy causing the expansion of space is most likely, according to links I posted above, caused by quantum fluctuations in space.

In one of the many versions of string theory I plowed through recently to answer another question of mine, a photon is represented as an open ended vibrating string where as fermion is represented as a closed string. I you mentioned previously, strings are "modes of vibration" in space, a space full of quantum fluctuations or vibrating strings.

 

 

 

On 11/6/2017 at 7:28 PM, swansont said:

Why does it matter who answers? You keep repeating yourself, and the answers are still the same.

What I think dark matter is is of no importance. I don't study gravity or cosmology. I would have no special insight into the problem. 

Additional stuff keeps turning up, and no I am not repeating myself, I think I have changed my mind on the existence of dark matter several times throughout this thread. 

Very few people have special insight, only Mordred has put forward a good idea as to what dark matter may have been, which you and strange discounted, I assumed therefore you both must know something about what you were talking about, it just goes to show how wrong we can all be. 

Link to comment
Share on other sites

On 11/8/2017 at 0:59 PM, Strange said:

You made the claim that photons cause quantum fluctuations. It is up to you to support your claim (see also: burden of proof).

In addition to the above, you may find this interesting, or not since you most likely already know about this 

The first observation of the quantum foam came from tiny disturbances in the energy levels of the electron in a hydrogen atom. A second effect was predicted in 1947 by Hendrik Casimir and Dirk Polder. If the quantum foam was real, they reasoned, then the particles should exist everywhere in space. Further, since particles also have a wave nature, there should be waves everywhere. So what they imagined was to have two parallel metal plates, placed near one another. The quantum foam would exist both between the plates and outside of them. But because the plates were placed near one another, only short waves could exist between the plates, while short and long wavelength waves could exist outside them. Because of this imbalance, the excess of waves outside the plates should overpower the smaller number of waves between them, pushing the two plates together. Thirty years after it was first predicted, this effect was observed qualitatively. It was measured accurately in 1997.

http://www.pbs.org/wgbh/nova/blogs/physics/2012/10/quantum-foam-virtual-particles-and-other-curiosities/

Link to comment
Share on other sites

1 hour ago, interested said:

 Photons as you are aware exhibit both wave and particle properties, and they are affected by gravity. They therefore distort space in the same way normal mass does except they are not stationery like a normal particle. Distortions in space are quantum fluctuations. LIGO detected gravitational waves ie distortions in space.

Gravitational waves are not quantum fluctuations.

Quote

Additional stuff keeps turning up, and no I am not repeating myself, I think I have changed my mind on the existence of dark matter several times throughout this thread. 

Very few people have special insight, only Mordred has put forward a good idea as to what dark matter may have been, which you and strange discounted, I assumed therefore you both must know something about what you were talking about, it just goes to show how wrong we can all be. 

I think it's more likely you have misunderstood what's been presented.

18 minutes ago, interested said:

In addition to the above, you may find this interesting, or not since you most likely already know about this 

The first observation of the quantum foam came from tiny disturbances in the energy levels of the electron in a hydrogen atom. A second effect was predicted in 1947 by Hendrik Casimir and Dirk Polder. If the quantum foam was real, they reasoned, then the particles should exist everywhere in space. Further, since particles also have a wave nature, there should be waves everywhere. So what they imagined was to have two parallel metal plates, placed near one another. The quantum foam would exist both between the plates and outside of them. But because the plates were placed near one another, only short waves could exist between the plates, while short and long wavelength waves could exist outside them. Because of this imbalance, the excess of waves outside the plates should overpower the smaller number of waves between them, pushing the two plates together. Thirty years after it was first predicted, this effect was observed qualitatively. It was measured accurately in 1997.

http://www.pbs.org/wgbh/nova/blogs/physics/2012/10/quantum-foam-virtual-particles-and-other-curiosities/

 

How does this support your claim that photons cause quantum fluctuations?

Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.