How Can We Interact with Dark Matter for Sci-Fi Novel?

[Zguy1217]

As I have come to understand it - we have no current means of directly interacting with Dark Matter. We can only observe the gravitational effects that Dark Matter has on Baryonic Matter.

My question is: What forms of detection have been attempted and determined to not directly interaction with Dark Matter - other than light, because that is pretty obvious?

(I'm asking because I'm trying to put together a Sci-Fi novel that utilizes Dark Matter, and I don't want to get its interactions wrong)

Also, although I'm sure this answer is "We don't know yet", are there any likely particles, fields, or energies that can/would directly interact with Dark Matter?

 

[BL4CKB0X97]

As I have come to understand it - we have no current means of directly interacting with Dark Matter. We can only observe the gravitational effects that Dark Matter has on Baryonic Matter.

My question is: What forms of detection have been attempted and determined to not directly interaction with Dark Matter - other than light, because that is pretty obvious?

(I'm asking because I'm trying to put together a Sci-Fi novel that utilizes Dark Matter, and I don't want to get its interactions wrong)

Also, although I'm sure this answer is "We don't know yet", are there any likely particles, fields, or energies that can/would directly interact with Dark Matter?

All i know is that one their is that they are something sort of WIMP( weakly interacting massive Particle). So getting it to interacting is pretty difficult. I'd hazard a guess that it is unknown.
I would say more but it is based on my understanding of thanks i have read/see and would rather give fact rather thanks misguided assumptions.

But dark matter is still a theory,i believe.

 

[weirdoguy]

But dark matter is still a theory,i believe.

In science "theory" means something different than in ordinary language. Theory in science is the best thing we can have.

 

[newjerseyrunner]

It's true that we only directly observe it through gravity. However, most theories would mattamrically require that they also interact via the weak force. The problem is that would only be able to see that if it directly interacted with an atoms nucleus. Currently running experiments are watching for those (interaction with the nucleus creates a tiny flash of light.)

 

[Orodruin]

However, most theories would mattamrically require that they also interact via the weak force

How do you quantify this? It is certainly not true for axions or sterile neutrinos.

You also have indirect searches for decay/annihilation products and collider experiments looking for missing transverse momenta and/or monojets/monophotons.

 

[BL4CKB0X97]

In science "theory" means something different than in ordinary language. Theory in science is the best thing we can have.

Until its proven

 

[Orodruin]

Until its proven

This is one the absolutely most common misconceptions about the empirical sciences. You can never "prove" a theory. You test it to check whether it continues being a goid description in regimes where it has not been tested yet or to accuracies at which it has not been tested before. If the prediction fails you need to revise the theory, which does not make it "false", it makes it a bad description in the new regime. It does not invalidate the use of the theory in regimes where it is known to be sufficiently accurate. If this was not the case we would not be using Newtonian gravity for anything today - but we do.

 

[kimbyd]

My question is: What forms of detection have been attempted and determined to not directly interaction with Dark Matter - other than light, because that is pretty obvious?

The Wikipedia article has a good summary of the attempts at detecting dark matter:
https://en.wikipedia.org/wiki/Dark_matter#Detection_of_dark_matter_particles

There's some more detail at the linked article for WIMPs:
https://en.wikipedia.org/wiki/Weakly_interacting_massive_particles#Direct_detection

The basic idea is that what they're looking for in these searches is an unexpected interaction, typically with an atomic nucleus. They're looking for energy coming out of the experiment that they didn't see go into it, and for that energy to correspond to a particle of a specific mass. So far there's been nothing definitive, but we've only barely started to probe the expected sensitivity required to detect dark matter.

 

[Bandersnatch]

Until its proven

Have a read through this:
http://undsci.berkeley.edu/teaching/misconceptions.php
It'll explain exactly what is and isn't science.

 

[Buzz Bloom]

However, most theories would mattamrically require that they also interact via the weak force.

Hi newjersey:

I think that the technical word you use in the above quote is misspelled.
Did you mean

"metamerically": In a metameric manner
"metameric": exhibiting structural isomerism​

At this point I have to make a guess that you are using the term "metamerically" metaphorically because the only definitions for "structural isomerism" seem to be related to chemistry.

"structural isomerism": a form of isomerism in which the same atoms are arranged in different orders; either having the same or different functional groups
​

Would you please elaborate in non-technical language what you intended as the meaning of the quote?

Also, when you said "theories", did you mean

most theories of all types, or
most scientific theories,
or most physics theories,
or most particle physics theories?​

Regards,
Buzz

 

[Buzz Bloom]

They're looking for energy coming out of the experiment that they didn't see go into it, and for that energy to correspond to a particle of a specific mass.

Hi kimbyd:

I wonder if the usage of the technical word "theory" is properly applied to the concepts leading to the type of research you describe in the above quote. At the present time, there seem to be many still plausible competing ideas about what kinds of stuff dark matter will turn out to be made of. The usage of scientific "theory" that seems to me to be the most respected applies to a collection of related ideas that either

(1) have already been verified by experimental observation as being useful in the context of a reasonably wide range of application, for example, (a) general relativity, and (b) evolution,
or also perhaps
(2) have a single concept of what is being searched for, for example, the Higgs boson.​

With so many competing ideas about dark matter, I suggest a more accurate word for a concept leading to the kind of experiment you describe in the quote would be "speculation". Three examples of such ideas are: (a) WIMPs, (b) MACHOs, and (c) primordial black holes.

Regards,
Buzz

 

[kimbyd]

Hi kimbyd:

I wonder if the usage of the technical word "theory" is properly applied to the concepts leading to the type of research you describe in the above quote. At the present time, there seem to be many still plausible competing ideas about what kinds of stuff dark matter will turn out to be made of. The usage of scientific "theory" that seems to me to be the most respected applies to a collection of related ideas that either

(1) have already been verified by experimental observation as being useful in the context of a reasonably wide range of application, for example, (a) general relativity, and (b) evolution,
or also perhaps
(2) have a single concept of what is being searched for, for example, the Higgs boson.​

With so many competing ideas about dark matter, I suggest a more accurate word for a concept leading to the kind of experiment you describe in the quote would be "speculation". Three examples of such ideas are: (a) WIMPs, (b) MACHOs, and (c) primordial black holes.

Regards,
Buzz

No, speculation is highly inaccurate. We have quite a lot of evidence that supports the existence of dark matter. That the evidence is not currently specific enough to single out a single, specific dark matter candidate does not justify the implications that come with the term.

The way to understand it is that "WIMP" is not a single theory, but rather a class of related theories with common elements.

And by the way, MACHOs are basically ruled out by CMB data, as no compact objects could have formed before the emission of the CMB, but the dark matter signal is very apparent. Primordial black holes within a narrow mass range aren't yet ruled out by the data, but are considered a very exotic proposal. The leading class of theories are contained within the WIMP class of theories.

 

[Buzz Bloom]

No, speculation is highly inaccurate. We have quite a lot of evidence that supports the existence of dark matter.

Hi kymbyd:

Thank you for your reply. I think I must have not phrased my remarks clearly enough. I have no problem with the usage: "dark matter theory". However, the "WIMP theories" together with the now defunct "MACHO theory" and the "primordial black hole theory" all together seem to be too speculative to be "theories". Also, a "theory" that has had no positive experimental/observational support seems to me to be more accurately called a "speculation".

Regarding WIMPs, I understand from other threads on these forums (can't locate them right now) that the upper energy limit for plausible WIMP dark matter is not very far above what is currently measurable, and all of the lower range of energies have failed to achieve experimental support.

Is it still appropriate to use the term "MACHO theory" now that this "theory" is no longer in the running to be an explanation of what dark matter is?

Now, let is suppose hypothetically the the future experiments that explore up to the maximum theoretical energy for WIMP dark matter also fail to achieve positive results. Would the term "WIMP theory" still be proper terminology? I suppose "defunct MACHO theory" and "defunct WIMP theory" would still be a useful usage.

Regards,
Buzz

 

[kimbyd]

However, the "WIMP theories" together with the now defunct "MACHO theory" and the "primordial black hole theory" all together seem to be too speculative to be "theories".

I don't think you have the understanding of the subject matter to make that determination.

 

[rootone]

OK, so WIMPS are still being investigated, other theories seeming to be less plausible.
Maybe there is something we don't yet get what it is, like the famous singularities in relativity.
Like trying to measure the wind direction at the North pole.

 

[kimbyd]

OK, so WIMPS are still being investigated, other theories seeming to be less plausible.
Maybe there is something we don't yet get what it is, like the famous singularities in relativity.
Like trying to measure the wind direction at the North pole.

It's not possible to quantify the likelihood of things we haven't yet thought of. The best that can be done is to keep collecting new evidence, to push observations into new regimes, and hope that we'll find enough about the holes in current theories to guide the way to more accurate ones.

 

[Buzz Bloom]

I don't think you have the understanding of the subject matter to make that determination.

Hi kimbyd:

It is certainly quite possible that you know a great deal more than I do about dark matter research, and it also quite possible I have made a mistake. There are two points which I have been making regarding the use of the term "theory". Which one are you telling me is wrong.

1. None of the three categories of "theories" about what dark matter is made of ((a) WIMPs, (b) MACHOs, and (c) primordial black holes) have up until now had any experimental/observational support.
2. The proper use of the term "scientific theory" to describe scientific ideas requires that the ideas have at least some experimental/observational support.

(1) might be a mistake since it is possible that some experimental/observational support exists about (a), (b), and/or (c) that I am not aware of.
(2) might be a mistake if the scientific community generally considers it to be appropriate to use the word "theory" to describe some ideas in sense of "scientific theory" when there has been no experimental/observational support for these ideas.

With a few minor format changes, definitions of "theory" from

https://www.merriam-webster.com/dictionary/theory​

1. a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena - e.g.: the wave theory of light.
2. (a) a belief, policy, or procedure proposed or followed as the basis of action her method is based on the theory that all children want to learn. (b) an ideal or hypothetical set of facts, principles, or circumstances —often used in the phrase in theory - e.g.: in theory, we have always advocated freedom for all.
3. (a) a hypothesis assumed for the sake of argument or investigation. (b) an unproved assumption - syn.: conjecture. (c) a body of theorems presenting a concise systematic view of a subject theory of equations.
4. the general or abstract principles of a body of fact, a science, or an art - e.g: music theory.
5. abstract thought - syn.: speculation.
6. the analysis of a set of facts in their relation to one another.

The above are all definitions of "theory" as used in ordinary English. Which of the above do you believe are generally accepted by the physics community as a complete acceptable definition of "theory" when used in the phrase "scientific theory" as applied to ideas about physics?

The following is from

https://en.wikipedia.org/wiki/Scientific_theory
A scientific theory is an explanation of some aspect of the natural world that can, in accordance with the scientific method, be repeatedly tested, using a predefined https://www.physicsforums.com/javascript:void(0) of observations and experiments.[1][2] Established scientific theories have withstood rigorous scrutiny and are a comprehensive form of scientific knowledge.[3]
It is important to note that the definition of a "scientific theory" (often ambiguously contracted to "theory" for the sake of brevity, including in this page) as used in the disciplines of science is significantly different from the common vernacular usage of the word "theory".[4][Note 1] In everyday non-scientific speech, "theory" can imply that something is an unsubstantiated and speculative guess, conjecture, idea, or, hypothesis;[4] such a usage is the opposite of the word "theory" in science. These different usages are comparable to the differing, and often opposing, usages of the term "prediction" in science versus "prediction" in vernacular speech, denoting a mere hope.
Note 1: Per NAS 2008: "The formal scientific definition of theory is quite different from the everyday meaning of the word. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence."​

BTW: another word that might be correctly used rather than "speculation" for theoretical based scientific ideas without experimental/observational support is "conjecture".

Regards,
Buzz

 

[kimbyd]

Attempts to exclude certain models as not being theories are ultimately worthless, as they argue that these models are of less value based upon arbitrary conditions that have nothing to do with the usefulness of such models to science.

By large, actual scientists don't concern themselves very much with what a model is called, but on its contents. That's what's important.

 

[Buzz Bloom]

Hi Kimbyd:

Attempts to exclude certain models as not being theories are ultimately worthless, as they argue that these models are of less value based upon arbitrary conditions that have nothing to do with the usefulness of such models to science.

I think we will have to agree to disagree. I don't believe that a decision about the usage of the term "theory" changes in very many minds the usefulness of a conjecture based on sound theoretical ideas even without any observational support. The MACHO conjecture remains useful in that it led to observational data that proved it was wrong. The WIMPs conjectures remain useful without any (so far) observational support, because it leads to well planned experiments that should eventually lead to either support that calling it a theory is justified, or of a conclusion that, like the MACHO conjecture, it is also false.

By large, actual scientists don't concern themselves very much with what a model is called, but on its contents. That's what's important.

My concern with a scientist referring to a conjecture without observational support as a "theory" is that it creates confusion in the minds of non-expert but interested readers that the conjecture has actually been confirmed to be supported by observational evidence when it has not yet been.

Regards,
Buzz

 

[kimbyd]

My concern with a scientist referring to a conjecture without observational support as a "theory" is that it creates confusion in the minds of non-expert but interested readers that the conjecture has actually been confirmed to be supported by observational evidence when it has not yet been.

Well, you're in luck, because scientists only very rarely refer to dark matter as a "theory".

There are lots of things about the way science is explained to non-scientists that are misleading. This really isn't one of them. First, it's not done often. Second, it doesn't mislead people about the quality of evidence for dark matter.

 

[Buzz Bloom]

Second, it doesn't mislead people about the quality of evidence for dark matter.

Hi kimbyd:

I am willing to accept the possibility that statistics collected regarding

the fraction of people who are exposed to phrases like "WIMP theory of dark mater" who are thereby confused into thinking that some observational evidence exists about this "theory"​

would be a small fraction. I tend to doubt that such statistical data exists. If you know of any I would much appreciate seeing a link to a source. I am also curious about what motivates your opinion that the usage "doesn't mislead people about the quality of evidence for dark matter".

BTW: I agree that this kind of usage is rare. I made an internet search to find examples of this kind of usage. I looked at about 20 articles, and found only three that used "theory" in this sense.

https://www.sciencedaily.com/releases/2013/01/130124091545.htm
https://news.vanderbilt.edu/2013/06/10/dark-matter/
http://www.dailymail.co.uk/sciencet...mysterious-substance-objects-mass-planet.html
​

The only other examples I know that use term in this sense is in your post #12.

The way to understand it is that "WIMP" is not a single theory, but rather a class of related theories with common elements.

Regards,
Buzz

 

[PeterDonis]

I looked at about 20 articles, and found only three that used "theory" in this sense.

All of which would not be valid sources, since they aren't textbooks or peer-reviewed papers. If you are really interested in seeing how words like "theory" are commonly used by scientists, try textbooks or peer-reviewed papers.

But in any case, that is a question of words, not physics. It doesn't matter whether you call the idea that WIMPs account for dark matter a "theory", "hypothesis", "wild ass guess", or anything else. What matters is what specific claims the idea makes, and how they can be tested. Please focus discussion on the latter, not the former. Further posts about words rather than physics are off topic and will be removed.

 

[Zguy1217]

While I'm glad there's a lot of responses to this forum topic, can I request that we return to the topic at hand, rather than continuing to discuss the semantic usage of the word "Theory"?

 

[Chronos]

A 'theory' is little more than an educated guess. Without getting lost in semantics, it would be fair to say 'WIMP' is a good guess at the nature of dark matter based on what we know about the weak force. Unfortunately, experimental results have not been consistent with our knowledge of weak interactions. That does not mean the WIMP idea is a fail, it could just as easily mean our knowledge of the weak force is incomplete. Most scientists are willing to concede that point, which is why WIMP based experiments continue to get funded. That in no way invalidates other guesses about the nature of dark matter - axions, sterile neutrinos, etc. The problem with these other guesses is they tend to be much harder to test than WIMP based ideas. My guess is dark matter is more complex than we may suspect.

 

[rootone]

My guess is dark matter is more complex than we may suspect.

You mean that the observed gravitational phenomena which have been ascribed to WIMPs, MACHOs, modified gravity and so on ;
those phenomena may be the net overall effect of several dark matter candidates, it could be more than one thing.

 

[Chronos]

I see no compelling reason to constrain DM to a single particle species. For example, we already know that neutrinos can account for at least a small part of the DM inventory. We can also be confident that MACHO's comprise some fraction of the missing mass in galaxies. However, none of these known candidates are suitable for a big picture explanation of DM. I view it no more reasonable to account for DM with a single non-baryon species than it is to account for ordinary matter with a single baryon species. The main appeal of the single species DM idea is it is neat and simple. The truth always seems to turn out a little more complicated.

 

[kimbyd]

I see no compelling reason to constrain DM to a single particle species. For example, we already know that neutrinos can account for at least a small part of the DM inventory. We can also be confident that MACHO's comprise some fraction of the missing mass in galaxies. However, none of these known candidates are suitable for a big picture explanation of DM. I view it no more reasonable to account for DM with a single non-baryon species than it is to account for ordinary matter with a single baryon species. The main appeal of the single species DM idea is it is neat and simple. The truth always seems to turn out a little more complicated.

I think there are strong reasons to suggest that one species makes up the large majority of dark matter, for the simple reason that relatively small differences in interactions strength or mass can lead to very large differences in the resulting mass fraction.

It's certainly not impossible for more than one species to make up a significant dark matter component, but it would require a major coincidence for this to occur.

 

[nikkkom]

While I'm glad there's a lot of responses to this forum topic, can I request that we return to the topic at hand

I struggle to find a plausible scenario for dark matter use in a sci-fi. Okay, here's one way to make it "available". Let's say DM is indeed WIMPs and they are pretty heavy. Let's say over geological times, enough of them are trapped by planetary-sized chunks of mass and accumulate inside, so that (in sci-fi) you can bore into a cold core of a Mars-sized TNO (let's say its a trapped "foreign", non native Solar system object, and it is 12 billion years old, thus radiogenic heating is rather weak too) and find its core region to have noticeably enhanced density of DM.

What then? You still can not scoop this DM up - it would flow through any sort of walls, material as well as some magnetic confinement...

 

[Anon5000]

As I have come to understand it - we have no current means of directly interacting with Dark Matter. We can only observe the gravitational effects that Dark Matter has on Baryonic Matter.

My question is: What forms of detection have been attempted and determined to not directly interaction with Dark Matter - other than light, because that is pretty obvious?

Not to be too brutal, BUT - JUST to make sure you know, nobody reads novels anymore. I wouldn't expect the book to do well. (I would shoot a movie, and put a set together out of some plastic panels, but that's just me)

 

[Orodruin]

I struggle to find a plausible scenario for dark matter use in a sci-fi.

Depends on what you mean by "plausible" ... In Pullman's trilogy His Dark materials, he identifies Dust with "dark matter". Of course, in reality, Dust has very little to do with what we generally refer to as dark matter.

 

[nettleton]

I understand complex molecules occur in dust clouds in deep space via collisions between atoms and the dust, What is anticipated of a collision of an atom with dark matter?

 

[kimbyd]

I understand complex molecules occur in dust clouds in deep space via collisions between atoms and the dust, What is anticipated of a collision of an atom with dark matter?

Basically no effect. There have been a number of experiments attempting to measure collisions between dark matter particles and atomic nuclei, but they so far haven't found anything. This indicates that dark matter generally passes right through normal matter (similar to neutrinos).

 

[David Fosco]

I'm still learning but have a big problem with this Dark Matter.
1. Solar Systems and Globular Clusters apparently do not need them but the Galaxy does
2. To my understanding, the amount and strength are different for what is needed for a Galaxy vs A cluster of Galaxies.
3. I get the feeling that someone couldn't explain something about gravity so they made up this mysterious variable that somehow ties everything together.
Like I said I'm still learning about this stuff and surely not at the level of most on this Forum but is so interested in learning about how it all works.
I sure have a lot of respect and envy of the ones that have a great understanding of it all. If I had to give a theory about the missing Gravity that holds the large units together it would be the nothing of space has physical properties that shed when near matter. The further away the stronger it is. Thanks for letting me be a part of this.
David.

 

[kimbyd]

I'm still learning but have a big problem with this Dark Matter.
1. Solar Systems and Globular Clusters apparently do not need them but the Galaxy does
2. To my understanding, the amount and strength are different for what is needed for a Galaxy vs A cluster of Galaxies.
3. I get the feeling that someone couldn't explain something about gravity so they made up this mysterious variable that somehow ties everything together.
Like I said I'm still learning about this stuff and surely not at the level of most on this Forum but is so interested in learning about how it all works.
I sure have a lot of respect and envy of the ones that have a great understanding of it all. If I had to give a theory about the missing Gravity that holds the large units together it would be the nothing of space has physical properties that shed when near matter. The further away the stronger it is. Thanks for letting me be a part of this.
David.

These criticisms are honestly easy to answer, and are easily answered if you just do some internet searches about the evidence for dark matter.

The cosmic microwave background observations are particularly difficult to fit with anything but dark matter. The basic picture is that before the CMB was emitted, the universe was a plasma. Within a plasma, normal matter interacts strongly and experiences pressure. Dark matter does not. This leads to very different behavior, with normal matter bouncing out of gravitational potential wells while dark matter just collects in them. That kind of physical system can't really be explained by gravity modifications easily because modifications to gravity should just impact how deep the gravitational potential wells are. It shouldn't cause some of the mass to collect in wells while other mass bounces out.

The CMB observations allow us to measure the average density of both normal matter and dark matter to within about 1%.

 

[PeterDonis]

If I had to give a theory about the missing Gravity that holds the large units together it would be the nothing of space has physical properties that shed when near matter. The further away the stronger it is.

You don't have to give a theory. In fact, PF rules do not allow personal speculations. Asking questions is fine, but the fact that you have questions that you don't yet know the answers to does not mean you should try to guess answers.