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The Reason We Haven’t Directly Detected Dark Matter

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Re: The Reason We Haven’t Directly Detected Dark Matter

#151

Post by TheOtherHobbes »

maxxxxx wrote: post #87
dTal wrote: post #62

Earlier quoted context omitted.

I was about to post something similar. Before you act on the urge to go pontificating about how the scientists have clearly got it wrong for this reason or that reason, ask yourself - do you really think they haven't thought of that? Don't you think that, if there is mileage in your idea, there would certainly be scientists pushing it? Addendum: Science (and more generally, specialization) requires that we trust that…

I think the backlash against "experts" comes from the fact that way too many things get mixed into "science". When you look at fields like social sciences, nutrition and economics there are a lot of "scientists" that get publicity for results of very undisciplined work. They don't crosscheck their result for contradictions and often just seem to look for confirmation of their own biases. This contrasts to most physic…

There are also people - usually rich and/or corporate - deliberately muddying the water in fields such as climate change, pharma testing, and so on.

The public doesn't understand science, but it understands corporate PR even less.

The corporate PR industry has no plans to change this.

One of the biggest and most destructive wins for corporate PR has been the steady erosion of scientific credibility with FUD and character assassination, combined with science-for-hire commercial shilling. This has done huge damage to the credibility of tentative research, and made it very hard to get away with saying "We just don't know yet. So we need to keep looking, because looking where we don't have answers yet is our job."

But... not only does the public not understand how corporate PR operates. The scientific community often doesn't either.

There's a presumption of good faith in scientific debate. No matter how personal the to-and-fro gets, there's an assumption that everyone is doing the same job for recognisably similar reasons.

That presumption is wholly wrong in any situation with significant political and/or financial consequences outside of science.

Re: The Reason We Haven’t Directly Detected Dark Matter

#152

Post by lev99 »

The_rationalist wrote: post #136
The_rationalist wrote: post #131

« On 25 August 2016, astronomers reported that Dragonfly 44, an ultra diffuse galaxy (UDG) with the mass of the Milky Way galaxy, but with nearly no discernable stars or galactic structure, may be made almost entirely of dark matter.[6][7][8] » Meta-source: https://en.m.wikipedia.org/wiki/Dark_galaxy

Isn't this a proof of the invisibility of dark matter ?

It's an observation that fits our theoretical models when dark matter is assumed.

It's indirect proof. The indirect proof is so overwhelming strong that any rational person will concluded with reasonable certainty that dark matter is real.

Directly detecting a dark matter particle will give us more data than "dark matter is real".

Re: The Reason We Haven’t Directly Detected Dark Matter

#153

Post by stephengillie »

burlesona wrote: post #130

This strikes me a lot like “flatland”, ie. there’s something there but we’re not equipped to perceive it. Our experiments are mostly like extreme extensions of our own senses - seeing and touching things. But could something exist entirely within a dimensional space that we can’t touch or see? And if so how would we ever figure out how to detect it ... and even more meta, what if it was impossible for us to perceive…

The problem is that gravity, like EM, follows an inverse-square rule. If gravity had a 4th dimensional component, we would expect to see an inverse-cube situation. The equation is: 1/(1-dimensions)

Youtube video that explains this in depth: https://www.youtube.com/watch?v=3HYw6vPR9qU&t=726s

Re: The Reason We Haven’t Directly Detected Dark Matter

#154

Post by cygx »

TangoTrotFox wrote: post #133
krapp wrote: post #56

I like how we have an article explaining the rationale behind dark matter and the scientific principles that lead to the conclusion that it exists, but most of the threads here are simple declarations that no, they must all simply be wrong or not considering some simple alternative. Can people maybe, just maybe not assume that scientists are idiots or, as once dead commenter puts it, charlatans? If you disagree with…

There is something else you should also consider here. As theoretical physics and experimental physics have started to grow further and further apart, there are people who have devoted their entire careers, in many cases their entire lives, to purely theoretical pursuits which may in the end simply be invalid. But at some point you reach a point of no return in your career - in that you would need to effectively rebo…

This should, in and of itself, begin to cast down on the hypothesis even lacking a better alternative.

Only if your search was exhaustive: Scooping up a spoonful of ocean is not enough to conclude fish do not exist...

Re: The Reason We Haven’t Directly Detected Dark Matter

#155

Post by burlesona »

dwaltrip wrote: post #139
burlesona wrote: post #130

This strikes me a lot like “flatland”, ie. there’s something there but we’re not equipped to perceive it. Our experiments are mostly like extreme extensions of our own senses - seeing and touching things. But could something exist entirely within a dimensional space that we can’t touch or see? And if so how would we ever figure out how to detect it ... and even more meta, what if it was impossible for us to perceive…

Well, it has a gravitational effect, so it definitely exists inside of our normal spacetime. Scientists have explored alternative models of gravity or spacetime with additional spatial dimensions and things like that. As far as I know, none of them are very promising. There was an interesting PBS space time video about one example recently: https://youtu.be/3HYw6vPR9qU Of course, it is definitely interesting to think…

Interesting, I didn’t know that!

I guess for me the analogy is to the sphere in flatland being perceived as a circle - we can see evidence of dark matter but so far we can’t really detect or measure it directly. I wonder if the gravitational effect is the only clue that we’ll find inside “normal” spacetime.

The most exciting thing about that is the idea that the hunt for dark matter might eventually lead to an understanding of the “rest of the universe” where we would otherwise never have a hint of its existence.

Re: The Reason We Haven’t Directly Detected Dark Matter

#156

Post by mixmastamyk »

Believe the issue people have with “dark matter” is really about the term, it points to a so-far unprovable solution as a goal rather than a problem. It elevates a hypothesis to already solved, just need evidence. If they called it the “galactic paradox” it would be more easily recognized as a problem to work on.

You can downvote but it only proves the perception problem, not wanting to hear it doesn’t help.

Re: The Reason We Haven’t Directly Detected Dark Matter

#157

Post by spiritcat »

gbrown wrote: post #86
krapp wrote: post #56

I like how we have an article explaining the rationale behind dark matter and the scientific principles that lead to the conclusion that it exists, but most of the threads here are simple declarations that no, they must all simply be wrong or not considering some simple alternative. Can people maybe, just maybe not assume that scientists are idiots or, as once dead commenter puts it, charlatans? If you disagree with…

People somehow feel uniquely qualified to speculate wildly about theoretical physics. It's bizarre in a forum full of technical-minded people.

its the only worthwhile thing left to speculate about. well that and i guess like number theory. aka life, universe, everything in it.

and even if someone figures it out i probably won't understand it :/

Re: The Reason We Haven’t Directly Detected Dark Matter

#158

Post by matt_kantor »

The_rationalist wrote: post #134
slacka wrote: post #107

Despite recent some initial evidence to the contrary,[1] I'm still a fan of the idea that dark mater is actually concentrations of matter/energy outside of our universe. If string theory is true, gravity does leak into the multiverse, and we survive the Great Filter, then someday we may be able to use gravity to communicate universes outside of our own. https://www.sciencenews.org/article/gravity-doesnt-leak-larg...

Then why would dark matter be detected in galaxies but not in void space ? Why would those external world matter/energy be spatially syncrhonised at the place of galaxies ? Ockham Razor to the rescue.

I'm just a layman, but the parent said "if string theory is true, gravity does leak into the multiverse". Given that I'd imagine the clumpiness of our universe could influence the clumpiness of nearby universes (and vice versa).

Re: The Reason We Haven’t Directly Detected Dark Matter

#159

Post by TangoTrotFox »

cygx wrote: post #154
TangoTrotFox wrote: post #133

Earlier quoted context omitted.

There is something else you should also consider here. As theoretical physics and experimental physics have started to grow further and further apart, there are people who have devoted their entire careers, in many cases their entire lives, to purely theoretical pursuits which may in the end simply be invalid. But at some point you reach a point of no return in your career - in that you would need to effectively rebo…

This should, in and of itself, begin to cast down on the hypothesis even lacking a better alternative. Only if your search was exhaustive: Scooping up a spoonful of ocean is not enough to conclude fish do not exist...

That's really the problem here though. You cannot falsify dark matter, and you cannot prove a negative. Imagine I say there is a 5 headed green deer that weighs 2000 pounds and can speak Gaelic, but it's really good at avoiding being spotted - so good in fact that you can even look at right at it and might not see it. And you can even touch it and not even know you're touching it! What would you could consider an exhaustive proof of its lack of existence?

You can leave carrots everywhere, but perhaps it doesn't like carrots. Or maybe you didn't spot it eating those carrots. Maybe you left them in the wrong spot, or at the wrong time. Maybe you need bigger carrots. Maybe you need smaller carrots. Maybe it likes cooked carrots instead of raw carrots. Maybe you need a better camera. Maybe the reason you camera didn't catch it is because you weren't using a flash, or maybe you need to setup an infrared camera, maybe you need to play a Gaelic greeting on loop, etc, etc. You can compile a literally infinite number of ideas to try to detect our dear deer.

Instead with non falsifiable theories, all you can do is approach them from an abundance of failures. You've tried carrots, you've tried infrared, you've tried ..., and it's still not coming out. Each failure makes it more and more likely that our deer simply does not exist. Of course this does not mean it definitively does not, but nothing will ever mean that.

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