Scientists say dark matter doesn't exist

[Irony]

... By material evidence, I mean some thing that directly exhibits measurable properties...

A measurable property like gravity perhaps? I'm not going to go out of my way to point you to evidence that has already been pointed out to you in this very topic. Ignore it all you like, but everyone else seems to be able to see it just fine, so your pretending it's not there is not particularly convincing.

 

[tsg]

I am not a theoretical physicist or a mathematician,

Which pretty much makes you unqualified to evaluate the evidence.

proof is shown by material results, rather than by an incomprehensibly written paper in a relatively obscure scientific journal

That you don't understand it doesn't make it not true.

However, I have to admit that those scientists have greater knowledge than I do, and that they may actually be on to something. But, I'd also like to see some item or principle that I could exploit in my work. That's what I'm flogging the dead horse about.

What is this electricity of which you speak? When I can go to Wal*Mart and buy a bag of "electrons", then I will believe in it.

 

[robinson]

And I want to be king of Fnordia and wear a shiny hat.

Unlike dark matter, there is a possibility you can find a shiny hat.

 

[T'ai Chi]

I claim it is in an undetectable multiverse.

lol

 

[GodMark2]

I claim it is in an undetectable multiverse.

lol

If it is undetectable, then how did we detect it?

 

[Checkmite]

However, it's worth contemplating the fact that there are pictures of it.

My brain calls timeout when I try to contemplate the time-scales involved, considering the distance all that light had to travel to get here.

 

[Fnord]

So, let me get this straight...

1) There is an undetectable 'something' exerting force on all matter in the universe.

2) The force it exerts is used to explain certain phenomena that had puzzled scientists before its 'discovery.'

3) Only a select few understand the real nature of this 'something' and the force it exerts.

4) Anyone who might have any real understanding of this 'something' is loath to share it, except with other members of the select few.

5) Anyone who exercises a healthy measure of skepticism and asks for material - not theoretical - proof of this 'something,' is ignorant and unqualified to evaluate the proof in the first place.

6) Proof of the existance of this 'something' rests solely upon accepting the validity of the authorities who formed the hypothesis in the first place.

Now, you all have to admit that from a certain point of view, it all seems to imply something supernatural.

I'm not saying that the Dark Matter hypothesis is invalid, but so far, the only 'proofs' have been less than convincing.

I am saying from an engineering standpoint that without a practical application, the Dark Matter hypothesis is irrelevant, no matter how truthful and valid it may be.

 

[Fnord]

Personally, I got to go with the majority on this one; dark matter is too good an explanation. But I'm not set on it. However, it's worth contemplating the fact that there are pictures of it.

Okay, I see a picture with light and dark areas. I also see in the second paragraph of the linked article...

Astronomers have long suspected the existence of the invisible substance of dark matter...

If my feeble mind can grasp this complex word 'in-vizz-i-bl', it means that Dark Matter is transparent, not opaque.

In the fifth paragraph...

Although astronomers cannot see dark matter, they can infer its existence in galaxy clusters by observing how its gravity bends the light of more distant background galaxies.

So how can the picture show dark matter, as stated in the eighth paragraph?

"I was annoyed when I saw the ring..."

Okay, so which is it? Is Dark Matter transparent, translucent, or opaque? Can it be seen or not? Why does there seem to be equivocation or conflict, even from scientists, about the properties of Dark Matter?

It can be detected by its gravitic effects on light and matter. So why not just call it 'matter'? Is it necessary to posit the property of invisibility? Why not just say "We can't see it, but we know it's there by using the same principle we use to find extrasolar planets"?

 

[blobru]

... So how can the picture show dark matter, as stated in the eighth paragraph? ...

The ghostly ring is a mathematical model, derived from gravitational lensing effects, superimposed on a Hubble image of the cluster (a bit confusing).

The dark matter's distribution, to my ignorant eye at least, looks like a water drop ripple.

 

[PixyMisa]

1) There is an undetectable 'something' exerting force on all matter in the universe.

No. It's detectable. We can't see it, but we can observe its gravitational effects.

2) The force it exerts

Gravity.

is used to explain certain phenomena that had puzzled scientists before its 'discovery.'

Galaxies and galactic clusters act as though they are influenced by more gravity than we can account for from the visible matter.

3) Only a select few understand the real nature of this 'something' and the force it exerts.

We don't know what it is. We know the force it exerts is gravity.

4) Anyone who might have any real understanding of this 'something' is loath to share it, except with other members of the select few.

Now you're just making stuff up.

5) Anyone who exercises a healthy measure of skepticism and asks for material - not theoretical - proof of this 'something,' is ignorant and unqualified to evaluate the proof in the first place.

The evidence has been presented to you. It's pretty straightforward. We don't have physical samples of dark matter, and you couldn't see it if we did.

6) Proof of the existance of this 'something' rests solely upon accepting the validity of the authorities who formed the hypothesis in the first place.

And now you're just flat-out lying.

Now, you all have to admit that from a certain point of view, it all seems to imply something supernatural.

Not even remotely. We observe a physical effect. We cannot fully account for this effect based on one class of matter. Hypothesis: There is another class of matter.

Other possible hypotheses: Gravity works differently at different scales (the evidence does not seem to support this); Multiple independent observations are all incorrect.

I'm not saying that the Dark Matter hypothesis is invalid, but so far, the only 'proofs' have been less than convincing.

It's not a proof. You don't get proof. You only get evidence.

I am saying from an engineering standpoint that without a practical application, the Dark Matter hypothesis is irrelevant, no matter how truthful and valid it may be.

No, you're saying that the hypothesis sounds like a conspiracy theory or a supernatural claim.

 

[PixyMisa]

Okay, I see a picture with light and dark areas. I also see in the second paragraph of the linked article...

If my feeble mind can grasp this complex word 'in-vizz-i-bl', it means that Dark Matter is transparent, not opaque.

Yes.

In the fifth paragraph...

So how can the picture show dark matter, as stated in the eighth paragraph?

It bends the light of other objects. That's what we see.

Okay, so which is it? Is Dark Matter transparent, translucent, or opaque?

Transparent. It does not interact with the electromagnetic force.

Can it be seen or not?

No.

Why does there seem to be equivocation or conflict, even from scientists, about the properties of Dark Matter?

Because, apart from its gravitational effects, and the fact that we can't see it, we don't know what those properties are.

It can be detected by its gravitic effects on light and matter.

Correct.

So why not just call it 'matter'?

You can, if you like. Because it is. It is also invisible.

Is it necessary to posit the property of invisibility?

We can't see it. Do you have a different definition of "invisible"?

Why not just say "We can't see it, but we know it's there by using the same principle we use to find extrasolar planets"?

That's what "dark matter" means.

 

[Paulhoff]

http://www.badastronomy.com/bablog/2007/05/15/hubble-finds-dark-matter-smoke-ring/

Paul

 

[TV's Frank]

Yeah, I think there's a lot of confusion here. Let's start with this:

There exist inconsistent observations. There are many ways to weigh the universe. One of them is to add up all the shiny glowing stuff, figure out what's it's made of, and get the mass. You do this in the universe, and you get a certain answer.

Other ways include gravitational lensing and measuring velocities, and getting the amount of mass in the universe that way. When you do these measurements in the real universe, you get a BIGGER ANSWER than just by counting up glowing stuff.

So, like I said before: we have inconsistent sets of observations. Three possibilities:

1) One or more sets of observations are wrong.

2) The way we think gravity works is wrong.

3) There is stuff in the universe that is not hot and glowy.

30 years of observations and testing and re-testing tells us that 1) is out. So, is gravity wrong? Well, maybe. The problem is that this discrepency exists at ALL SCALES, from galaxies on up, and it's hard to modify gravity in such a way as to make this true.

That leaves the third option: there is stuff in the universe that is not hot and glowy. We might call this "dark matter". For awhile, there was debate: was this stuff just normal matter that is dim (like a failed star), or a new kind of exotic matter that does not even interact with light (like a neutrino)? For many reasons, we are leaning to option number 2. Why?

Well, if we assume that there's a big chunk of new stuff out there, then this lines up with predictions from OTHER observations, not related to weighing the universe, like the Cosmic Microwave Background, and statistics of structure in the universe.

Also, particle physics has separately come up with some new particles that have the properties that cosmologists need. The Large Hadron Collider is set out to test some of these theories. Bonus.

There are many many many experiments out there operating RIGHT NOW trying to catch a stray dark matter particle. Why? Instant Nobel, that's why.

It could very well be that our picture is completely and utterly wrong. If we fail to directly detect or produce a dark matter particle in, say, the next 10 years, we'll go back to the drawing board.

Also, someone might come a long and bring up a new modified theory of gravity, that explains all observations at all scales without the need for dark matter. Cool, everybody wins (but I've wasted a large part of my career thus far).

 

[TV's Frank]

I would also like the emphasize that observations CAME FIRST. Dark matter is our best attempt to explain these observations. This explanation is falsifiable (see above), but it seems to be doing well so far!

 

[Fnord]

So, it's matter. But it's invisible. We can't see it, but it's there. We can't prove that it exists, but we can detect evidence of its existence.

In that case, the buzzphrase "Dark Matter" means no more than "A material substance that we have not yet seen, measured, or held in our hands, but we have detected its effects on matter and light."

Okay, I'll buy that. We don't know what it looks like, but we know it's there because it attracts matter and bends light. Basic matter. Physics 101. Got it.

Now, how do scientists make the leap from "we can't see it" and "we don't know what its properties are" to "It must be invisible!" Why posit a "special" state of matter beyond what current evidence allows? Why not just posit something like a normal hyperdense element (atomic #114+) that is simply ground down too fine, and dispersed too widely to see with current technology? I could buy into that, as well.

Otherwise, it sounds to me like a few too many scientists have been dipping into a little too much metaphysical woo a little too often.

 

[Fnord]

Yeah, I think there's a lot of confusion here. Let's start with this:

There exist inconsistent observations. {Snippety-snip}

Thank you. Your concise explanation makes more sense to me than all the previous posts combined. It is also something that I can take out to ordinary people and explain in simple terms without dumbing it down first.

Q: "What is Dark Matter?"

A: "There is stuff in the universe that is not hot and glowy. We might call this 'Dark Matter.' For awhile, there was debate: was this stuff just normal matter that is dim - like a failed star - or a new kind of exotic matter that does not even interact with light - like a neutrino? For many reasons, we are leaning towards the neutrino idea..."

Thanx again!

 

[CapelDodger]

And I want to be king of Fnordia and wear a shiny hat.

 

[Schneibster]

So, let me get this straight...

1) There is an undetectable 'something' exerting force on all matter in the universe.

No. It is by definition not undetectable if it is exerting a force; it can be detected by the action of that force. The force involved is gravity, and it has detectable effects on both visible matter and on light. The only source of gravity we know of is matter. This matter's distribution, based on the observed effects, is not the same as the distribution of light sources. It therefore does not emit light. An appropriate name for matter that we know is there by its gravity effects, but that does not emit light and is therefore dark, is "dark matter." And that is what we call it.

2) The force it exerts is used to explain certain phenomena that had puzzled scientists before its 'discovery.'

No one was or is puzzled; it's obvious that if there are gravitic effects upon light and visible matter, the most likely source (since we know of nothing else that creates gravity) is matter that does not emit light. In other words, dark matter.

3) Only a select few understand the real nature of this 'something' and the force it exerts.

No. No one understands the real nature of the dark matter; it is a mystery. However, the nature of the force is obvious; there is only one force known that can affect both the path of light and the path of matter, and that force is gravity. Unless there is new physics, and it's very unlikely, there is no other force that will do what we see happening.

4) Anyone who might have any real understanding of this 'something' is loath to share it, except with other members of the select few.

All we know has been shared. There's nothing more to know right now; we need more information to figure out anything more, and we're doing all we can to get it. When we have it, it will be announced. If you'd care to go to school and get a degree in high energy particle physics or astrophysics, you could help. If not, you'll have to wait like the rest of us.

5) Anyone who exercises a healthy measure of skepticism and asks for material - not theoretical - proof of this 'something,' is ignorant and unqualified to evaluate the proof in the first place.

All the proof there is, you have seen. That there is something there is unquestionable; whether that something is actually matter, or is new physics, remains to be seen; most likely, it's matter, but what type of matter we have no idea. If it's not enough, your only choice is to wait. You are, at least, not alone, not even in your frustration at this state of affairs.

6) Proof of the existance of this 'something' rests solely upon accepting the validity of the authorities who formed the hypothesis in the first place.

No. Proof of the existence is based on observations that anyone can make, given the data to do so. That data has been presented to you. There is no more. Until there is, you'll have to wait like everyone else.

Now, you all have to admit that from a certain point of view, it all seems to imply something supernatural.

Actually, most likely, it's not supernatural at all; it's either matter that doesn't emit light, or it's new physics. Either way, it's not supernatural.

I'm not saying that the Dark Matter hypothesis is invalid, but so far, the only 'proofs' have been less than convincing.

If you find them so, then you have perhaps not understood their nature. I suggest that if you wish to understand what we find out when we find it out, you have some study to undertake. There are many here who it would appear are willing to help with that. But you'll have to do some work on your own as well. Those of us who do understand it do because we already have.

I am saying from an engineering standpoint that without a practical application, the Dark Matter hypothesis is irrelevant, no matter how truthful and valid it may be.

We don't know how relevant it might be, nor what practical applications might or might not present themselves once we understand it better. In most cases where we have found new things, practical applications that we could not have imagined until we knew what we were dealing with have emerged. Whether that will be the case here remains to be seen, and we are all waiting just as anxiously as you are. Though it would appear some of us have more patience.

 

[Schneibster]

Okay, I see a picture with light and dark areas. I also see in the second paragraph of the linked article...

The dark areas are areas where we can see the light has been bent. We don't know what bends it; it doesn't emit light, so we can't see it. We call it "dark matter." If this seems somewhat apocryphal to you, know that it does to everyone else, too.

If my feeble mind can grasp this complex word 'in-vizz-i-bl', it means that Dark Matter is transparent, not opaque.

Apparently so, but that doesn't mean it doesn't affect light and matter.

In the fifth paragraph...

So how can the picture show dark matter, as stated in the eighth paragraph?

By its effect on light coming from behind it. It bends it.

Okay, so which is it? Is Dark Matter transparent, translucent, or opaque? Can it be seen or not? Why does there seem to be equivocation or conflict, even from scientists, about the properties of Dark Matter?

It cannot be seen by its own light, because it doesn't emit any, and it cannot be seen by light it blocks, because it doesn't block light. It's transparent. However, because it has mass, it makes gravity, and gravity affects both light and other matter. We can see these effects.

It can be detected by its gravitic effects on light and matter. So why not just call it 'matter'? Is it necessary to posit the property of invisibility? Why not just say "We can't see it, but we know it's there by using the same principle we use to find extrasolar planets"?

That's what "dark matter" means. Technically speaking, extrasolar planets are dark matter, too; we can't see them. Of course, that's not what people mean by "dark matter;" they mean that thing that affects light from behind it as we observe that light to be affected, and that affects galaxies as we see they are affected in their rotation curves.

 

[TV's Frank]

Thank you. Your concise explanation makes more sense to me than all the previous posts combined. It is also something that I can take out to ordinary people and explain in simple terms without dumbing it down first.

Q: "What is Dark Matter?"

A: "There is stuff in the universe that is not hot and glowy. We might call this 'Dark Matter.' For awhile, there was debate: was this stuff just normal matter that is dim - like a failed star - or a new kind of exotic matter that does not even interact with light - like a neutrino? For many reasons, we are leaning towards the neutrino idea..."

Thanx again!

Glad to help! One bit of caution - neutrinos themselves have been ruled out as dark matter (well, most kind of neutrinos, but that's too detailed). Our best current guess is that dark matter is an exotic particle LIKE neutrinos, in that it does not interact with light or normal matter, except through the weak interaction.