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Comment by gmjoe | Hacker News Reader

Agreed 100%. Indeed, this is one of the best articles I've come across which covers several of the reasons we believe dark matter exists, as opposed to us just needing to modify the theory of gravity.

For whatever reason, dark matter seems to repeatedly rub people the wrong way today, more so than any other scientific concept I can think of. I actually wonder if it's something psychological -- if the universe is only 1/6 normal matter, it makes us feel even more insignificant than we already do, in the vast, seemingly infinite universe? Or maybe it's just the name, sounding too much out of fictional Star Trek.

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It's really difficult to have something useful or interesting to say as a layperson about dark matter (or most science fields) so people rely on tropes.

Special and General Relativity - "it's all relative man" Quantum Mechanics- "spooky action at a distance" Dark Matter - "if you can't see it, maybe it's just not there" Flat Earth - "you can't prove it's round"

There are more complex versions of this like the interesting, but debunked Tao of Physics and various cranks with new theories of everything (or perpetual motion), but they aren't accessible or interesting to the masses because they don't fit a convenient narrative.

Most big science and engineering takes a lot of work, understanding, and time to be accepted or have a big impact, but we're always looking for the new News.

I think one reason may be that people are used to the "completeness" of physics; it's the science that people seem historically most ready to declare "done", and it does explain a lot very well. This may make it particularly unsettling to learn about this vast frontier of ignorance.

Really? Who are these people that consider physics to be complete? I'm kind of skeptical that there's a large body of folks that know enough about physics to even ponder its completeness, but who also are unaware of the discrepancies between general relativity and quantum mechanics.

>For whatever reason, dark matter seems to repeatedly rub people the wrong way today, more so than any other scientific concept I can think of.

I think that it is because it is so hard to understand. You can't see it or touch it but it is supposed to make up the majority of mater in the universe. So what is it then? For a lot of people that's a hard thing to get and it would be easier if the answer was something we understood like the scientists being wrong.

In that way it isn't any different than creationists or flat-earthers. Of course dark matter "deniers" don't have the same religious convictions of creationists.

Consider something. What is it that makes god did [x] an improbable hypothesis? The fundamental reason is that there is no direct evidence of said god. There is indirect evidence and logical arguments that can favor a god, but that means nothing when you cannot observe a god, you cannot measure a god, and there is no direct evidence for that god.

Dark matter still holds more in common with the divine than the practical, for now. We've developed and carried out a slew of extremely clever experiments to try to affirm its existence, yet each and every experiment has returned a resounding negative. This is one of the biggest problems with the gulf between experimental and theoretical physics that's been rapidly expanding over the past several decades.

I get what you’re saying. I think you could be way more clear and articulate (took me about 3 reads to understand that you’re just agreeing with the well received parent, I think). I hope that is the reason for the downvotes and not simply people not wanting to hear that rationalism is just as dogmatic as anything it has displaced. Sure it’s better (in the more pragmatic sense), but it still depends on sets of axioms regarded as truth and fails to present explanations for plenty of observed phenomena. It also is strictly not philosophic so it can’t answer “Why?” nor can it yield any sort of ethical/moral framework(s) for understanding reality.

> Of course dark matter "deniers" don't have the same religious convictions of creationists.

Can you support that "of course"? I'm not so sure that there is no correlation. E.g. it is known that the same persons who tried to convince us that the "smoking is not dangerous" try to convince us that the "global warming doesn't exist, or at best it's beneficial." There are definitely the circles that immediately welcome and use any way to raise the doubt in the relevance of the majority of the scientific claims. It is intentional, it is supported by a lot of money, and it comes not only from one political direction. It is complex, it's not only a single ideology or a single religious group, but there are multiple correlations.

See the books: "The War on Science" by Shawn Otto and "Merchants of Doubt" by Oreskes and Conway.

For me, I have always had a problem with how dark matter was portrayed in the media, even more scientific media. It is only fairly recently that scientists have been communicating dark matter as a problem with several possible solutions to laypeople. Before it went kinda like this: "we are unable to detect 80% (or whatever number) of the mass in the universe and we think it is non-baryonic matter". As someone trained in science, but not physics, that sounds like a huge discrepancy suggesting an incorrect theory. But I all hear until recently is that "our theories are right, our observations are wrong". But usually it is the opposite. I'm oversimplifying but that was the general impression. More recently the media and scientists have been doing a better job admitting that something may be wrong with general relativity but the leading hypothesis is non-baryonic matter.

The discrepancy though is that a lot of the "observation" as I'd put it, too, is rather theoretic. It's a false dilemma and that's the problem. It's not just better measurements that are needed, but knowing where to look. If one is so far removed from the topic that there is no difference, it doesn't really make sense to speculate, except to show how much one doesn't understand.

Maybe it's just me but I remember back in the 1980's the first simulations of galaxies didn't work unless you added a lot more matter than was known even then to exist. That said to me that there is an unknown... of some sort. Because we're not even talking relativistic effects really. I have no dog in all of this because I'm supremely confident I would understand it even if the problem proves tractable. (And it might not be, for instance maybe dark matter just does not interact with normal matter at all)

Getting po'd at the media for not being able to explain stuff that scientists don't understand, might as well yell at a jellyfish.

Even scientists communicating directly to the public is what I'm talking about rather a journalism major not understanding physics.

Not sure I'd want to play the psychologizing game here. It could just as easily be used to explain the success of Dark Matter as a topic of discourse in the public imagination.

"Wow, look how insignificant it makes us feel, how insightful", or, "Just imagine how much is hidden from us every day!"

Yes, that must be it. Everything else about astronomy I'm perfectly fine with, but dark matter makes me feel insignificant. It's no problem however that many ... equate dark matter with some tangible notion of one theory or another and that their (and my) ignorance is staggering; Or that a negative result, like we can't bring two calculations into agreement, is treated like a result that found a real thing, while it's quite the opposite.

The simple problem is that DM is often defined as "a form of matter", when it could be multiple different forms. It's just the semantics that irks me. And then, if they will find maybe a new particle to account for at least some of the motion we couldn't explain, I will still be on the fence, because its not clear at all how to distinguish such from a virtual particle. That's nevertheless just a matter of semantics. The actual theory is probably way over my head. Therefore, doubt about the prediction for dark matter is just as much provoked by curiosity as for the proposed explanations. Ultimately, most explanations would be, in a mundane sense, turn out rather boring. So the question is, what's the deeper insight, as it goes for cosmology, what's the significance for life in general? There's a lot we don't know? I didn't even know that!

For me its the similarity to another pre-relativistic concept- the invisible ether between the worlds- that rubs me the wrong way.

And its tough to imagine the consequences of something you are absolutely not able to detect, you could be flying towards with 250 km/s. Its kind of scary- imagine you hit something like that and it causes earth quakes or a shake up of the solar system. Just think if that missing gas giant was actually a Blob of DM cycling the solar system.

And, well - the situation seems similar to this over focused on the problem situations you sometimes have in coding. Everyone has committed to a very narrowed down problem solution, that is just not working out, but instead of stepping back, a thousand angles are tried to solve the problem in the narrow scope.

Many here, just want to help. Which, given the Enlightenment as a project of everyone capable, against a Elite fighting for dogmatic ignorance - is a good thing in my book.

The article is missing in my opinion a confidence rating for every observation- how often this has been tested in experiments or observed in space. Otherwise it was good.

> And its tough to imagine the consequences of something you are absolutely not able to detect, you could be flying towards with 250 km/s. Its kind of scary- imagine you hit something like that and it causes earth quakes or a shake up of the solar system.

If it was capable of doing this, we would observe it doing the same to light on its way toward us - gravitational lensing in other words. If your scenario was possible, we would've definitely made observations to that extent, but we haven't.

For what it's worth - neutrinos fit your description right here. There are a trillion of them passing through your hand every second, essentially without interacting at all (from https://what-if.xkcd.com/73/).

> but instead of stepping back, a thousand angles are tried to solve the problem in the narrow scope.

What makes you think nobody has stepped back? Tons of people have stepped back and proposed lots and lots of alternatives. Dark matter is the only one that can explain all the phenomena mentioned in the article. It is the result of a lot of stepping back and failing even more in the other directions.

>> dark matter seems to repeatedly rub people the wrong way today, more so than any other scientific concept I can think of.

Because, while interesting to a great many scientists, the practical implications of this knowledge are centuries away. Defining dark matter, understanding the backbone of our universe, isn't going to cure cancer. It isn't going to fix global warming. It isn't going to get us to Mars. So when people read of massive experiments throwing unending brainpower and money into the DM hunt, it is natural for them to react as they do. Astronomers give us pictures of far away places that satisfy our natural need to explore. DM hunters stare at numbers and statistics, generating papers and messy diagrams. They aren't fighting an uphill PR battle.

There are also a not-small number of people for whom the DM hunt represents a challenge to their fundamental beliefs. Talk of colliding galaxies billions of light-years away conflicts with the young-earth model that is part of their daily lives. Rather than criticize on that basis and appear ignorant, they lash out on other grounds.

How do you know it won't cure cancer? Marie Curie checked out some invisible physics and discovered radioactivity. Now we use it to treat cancer.

I suspect that practical outcomes and technologies arising from understanding dark matter will be huge.

Also, I think you're missing the point of astronomy. "astronomers" today are generally astrophysicists or planetary scientists, and they are studying fundamental, mostly invisible, processes and substances.

> I suspect that practical outcomes and technologies arising from understanding dark matter will be huge.

I doubt it. More than 50 years after discovery of neutrinos, we are yet to find any practical outcomes or technologies.

Maybe not neutrinos specifically, but muon detectors are now being used for archaeology.

So you're saying a better understanding of nuclear reactions has not had practical implications? Just because the particle itself is 'useless' from a technological perspective doesn't imply the same is true for the accompanying theory...

The neutrino is part of the standard model. The dark matter may easily be entirely new physics, outside of the standard model. The implications may be enormous.

Moreover, even if the dark matter itself doesn't itself lead directly to to new tech, it is very likely that subsequent discoveries will.

Neutrinos theoretically can be used for nonproliferation at least :).

Time from discovery of nuclear physics to nuclear devices was less than 50 years

Same for experimental planes to first commercial flights.

So it might take centuries, but it also might not.

The technology spinoffs from DM-hunting are notable for the broader community.

The high-power dilution refrigerator that ADMX uses is of the same sort that the quantum-computing industry needs more and more of. Indeed, the students and staff being trained by ADMX are finding homes in both academia and across industry.

The high-sensitivity detector technology developed for WIMP searches have alternative use in nuclear non-proliferation monitoring. Improved detector ideas may continue to rattle down into medical imaging in the long run, improving some combination of sensitivity and dose.

The real prize, however, is what happens when the nature of dark matter is understood. It is a long-game play, but the technological implications might be on par with subjects like electricity, nuclear physics, quantum mechanics, etc. We won't know until we get there.

I know this. We know this. The public does not. DM hunters never talk about such things. All the public gets is "we used a massive detector to look something in this narrow spectrum, didn't find it, and will try again next year with an even bigger detector."

Any new detector should be described in terms of the new technologies it will require and how those new technologies will be used elsewhere. That gives it value regardless of whether it detects anything or not.

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