Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Dark Matter Filament Finally Found

samzenpus posted more than 2 years ago | from the there-it-is dept.

Science 190

An anonymous reader writes "Everyone is talking about the recent Higgs boson announcement by the scientists at CERN, but another significant scientific discovery was revealed this week as well. In a study published online in the journal Nature on Wednesday, scientists show that they have successfully found the first dark matter filament."

cancel ×

190 comments

Sorry! There are no comments related to the filter you selected.

bleh (-1)

Anonymous Coward | more than 2 years ago | (#40558941)

first post

Re:bleh (5, Funny)

Sulphur (1548251) | more than 2 years ago | (#40560511)

first post

Dark post; doesn't matter.

Here's a better article... (5, Informative)

slew (2918) | more than 2 years ago | (#40558945)

Re:Here's a better article... (5, Informative)

nickersonm (1646933) | more than 2 years ago | (#40559189)

Strangely there's no citation of the paper in that article. Here's the arXiv preprint. [arxiv.org]

Re:Here's a better article... (2)

erichill (583191) | more than 2 years ago | (#40560313)

Not so strange. Space.com is one of many more or less hermetically sealed news sites.

Thanks... (0)

Anonymous Coward | more than 2 years ago | (#40561075)

... for shedding some light on this.

Futurama fans already know... (5, Funny)

Yosho-sama (800703) | more than 2 years ago | (#40558949)

Futurama fans already know that that filament is a result of Nibblonian diarrhea being ejected into space.

Re:Futurama fans already know... (-1, Offtopic)

Yosho-sama (800703) | more than 2 years ago | (#40558981)

Really? Downmodded? Get a sense of humor.

Re:Futurama fans already know... (5, Insightful)

Lukano (50323) | more than 2 years ago | (#40558995)

Yeah this post didn't deserve a downmod. It was an applicable use of pop-culture humor.

Re:Futurama fans already know... (5, Funny)

Anonymous Coward | more than 2 years ago | (#40559229)

Did you mean "poop"-culture?

Re:Futurama fans already know... (5, Funny)

Anonymous Coward | more than 2 years ago | (#40559337)

Did you mean "poop"-culture?

What a shitty post.

Re:Futurama fans already know... (-1)

MobileTatsu-NJG (946591) | more than 2 years ago | (#40559473)

Is that your final answer?

so .. (2)

Randy_Leatherbelly (1983850) | more than 2 years ago | (#40558989)

what colour are they ?

Re:so .. (4, Funny)

Ranguvar (1924024) | more than 2 years ago | (#40559011)

so .. what colour are they ?

African American.

Re:so .. (-1)

Dunbal (464142) | more than 2 years ago | (#40559403)

Down-modded by the overly sensitive politically correct mod, because apparently brown people are not dark at all.

Re:so .. (0)

Ranguvar (1924024) | more than 2 years ago | (#40559679)

So I see.

It was a joke about how politically incorrect it seems to be now to refer to a dark-skinned person's skin tone.
I recall a case of bullying with some African American kid who was white, because the other kids didn't believe him.

It's all ridiculous. Race is race, skin color is skin color.

Re:so .. (-1)

Anonymous Coward | more than 2 years ago | (#40560091)

Race is race, skin color is skin color.
"Off color" jokes are off color.
If you have to explain them, they are even less funny. Forums can`t appeal to everyones taste. Hence mods. Try a knock knock joke next time.

Re:so .. (0)

Anonymous Coward | more than 2 years ago | (#40560995)

Knock knock.

Re:so .. (5, Funny)

Jane Q. Public (1010737) | more than 2 years ago | (#40560771)

"African American."

Umm... I'm not so sure such "dark" humor is quite appropriate.

Re:so .. (3)

marcosdumay (620877) | more than 2 years ago | (#40559453)

Transparent.

let me guess (-1, Troll)

Anonymous Coward | more than 2 years ago | (#40558999)

Let me guess, it was found sitting in the back of the galaxy.

Up next (2)

bryan1945 (301828) | more than 2 years ago | (#40559003)

The dark lightbulb. The darkbulb?

Re:Up next (5, Funny)

Anonymous Coward | more than 2 years ago | (#40559339)

Dark suckers. [msu.edu]

Re:Up next (0)

bryan1945 (301828) | more than 2 years ago | (#40559639)

Heh, that was fairly good. Never heard that one before.

well that article sucks (5, Informative)

slashmydots (2189826) | more than 2 years ago | (#40559013)

First of all, don't go to "page 2" and I use that term loosely. Secondly, it doesn't mention a single scientific detail about how they determined that the light was being bent around a filament-shaped object compared to the starts behind it actually being in the location the light suggests. It merely states "They used a model to subtract out the masses of the galaxy clusters and then fit the remaining mass with a model of what a filament might look like. They found that a filament must be present." So in other words, they didn't find anything other than a mathematical equation suggesting dark matter exists. Congratuations are in order indeed.

Re:well that article sucks - but read this (5, Informative)

slashmydots (2189826) | more than 2 years ago | (#40559063)

Aha, someone posted a hair bit of time ahead of me a much better article so let me ammend that with the short version:
There are 2 galaxies kinda far apart but they're really overlapped from Earth's point of view. Like one is almost entirely behind the other. So the back galaxy's light passes along where the filament would be estimated to be between the galaxies. So the light travels through the dark matter's gravitational field for a really long time, running practically parallel to the filament. Even after that much light gravity tugging, it's barely perceptable by our current telescopes. So someone had some pics of this set of galaxies from 2001 but never did anything with them because they didn't realize the opportunity. This new team noticed it, compared it to background light to detect additional possible lensing, and discovered unmistakeable slight lensing. So something is obviously there and it has to be a particular shape, density, and reflect no light.

Re:well that article sucks (4, Informative)

Lukano (50323) | more than 2 years ago | (#40559069)

Yeah because 'real' scientists would have hopped in their VW wagon and drove out to the galaxy to test and take measurements and be 100% sure....

The thing is bazillions of kilometers away, all they have to work with is mathemtical models to provide/disprove theories.

Re:well that article sucks (1)

mdenham (747985) | more than 2 years ago | (#40559407)

Well, on the "prove/disprove" front, all this has done is fail to disprove the existence of dark matter. There's a difference between that and actually proving its existence.

Personally, I'd prefer a slightly less ambiguous signal from one of the terrestrial dark matter detector experiments - which are currently giving either a "probably doesn't exist" result or a "these particles interact with normal matter less than neutrinos do" result. (These interactions are necessarily collision events, which means these have an effective cross-section smaller than a neutrino's.)

Re:well that article sucks (1)

filthpickle (1199927) | more than 2 years ago | (#40560389)

I watched about 5 episodes of TNG on BBC America yesterday waiting for it to get dark. Neutrinos seem so solve a lot of plot issues.

Re:well that article sucks (2)

hvm2hvm (1208954) | more than 2 years ago | (#40560633)

Look, scientists know we can't "be sure" that dark matter exists. But we can be sure that there is a gravitational anomaly around galaxies and now between them. That anomaly surrounds galaxies and links them with filaments. It should look like a large network of neurons.

Now, that anomaly can happen for any reason but it's just easier to assume that it's some kind of matter that we cannot see yet. What I'm thinking is that now that we know the Higgs boson exists we could try and see if it interacts with dark matter. I mean, if dark matter has mass (and gravity) it should interact with the Higgs boson at least.

Those are my thoughts anyway.

Re:well that article sucks (3, Insightful)

shaitand (626655) | more than 2 years ago | (#40561015)

"Well, on the "prove/disprove" front, all this has done is fail to disprove the existence of dark matter. There's a difference between that and actually proving its existence."

Science doesn't prove things exist or don't exist. The only thing science does is collect objective observations and come up with math that predicts what future observations will be given a set of conditions. Someone also makes up an interesting story to goes along with the math but aside from being consistent with the math the story (hypothesis/theory) doesn't really matter that much. Unlike the story, future observations can't break the math (although they can supercede it). Just ask Mr. Newton.

Re:well that article sucks (3, Funny)

jd (1658) | more than 2 years ago | (#40561081)

Volkwagon? VOLKSWAGON?! REAL scientists use police telephone boxes to travel intergalactic distances! Everyone knows that! Only wizards and mad scientists fly by car.

Re:well that article sucks (4, Informative)

rb12345 (1170423) | more than 2 years ago | (#40559075)

It would have helped if the summary had pointed at the actual Nature article [nature.com] or the ArXiv preprint [arxiv.org] .

Re:well that article sucks (0)

Anonymous Coward | more than 2 years ago | (#40559091)

Because anyone with the slightest interest knows gravitational microlensing studies are done by measuring the elliptical shapes of galaxies, and presuming a uniform distribution of actual orientations. And anyone who doesn't know it will get annoyed and leave before you finish explaining it.

Re:well that article sucks (1)

Sulphur (1548251) | more than 2 years ago | (#40560545)

Because anyone with the slightest interest knows gravitational microlensing studies are done by measuring the elliptical shapes of galaxies, and presuming a uniform distribution of actual orientations. And anyone who doesn't know it will get annoyed and leave before you finish explaining it.

And round about the podium was darkness, for the points of light had rearrainged themselves at a bar and exerted no gravitational attraction in the lecture hall.

Re:well that article sucks (2)

Jane Q. Public (1010737) | more than 2 years ago | (#40560809)

"So in other words, they didn't find anything other than a mathematical equation suggesting dark matter exists. Congratuations are in order indeed."

Yes, I get a kick out of how that article, as well as the one on space.com linked to above, are both written under the assumption that we know "dark matter" exists... but we know no such thing. It is still a matter of much controversy (no pun intended).

We have various theories to account for the observations. Among them the most popular of the string theories, which support the existence of dark matter. But on the other hand, there have been a number of recent findings that call "string theory" itself into strong question. Perhaps even rendering it invalid.

It bothers me greatly when "science" magazines and "science" websites report questionable theories as though they were demonstrated beyond reasonable doubt. In the case of strings and dark matter, nothing of the sort is even remotely true.

Re:well that article sucks (3, Interesting)

arth1 (260657) | more than 2 years ago | (#40560973)

Yes, I get a kick out of how that article, as well as the one on space.com linked to above, are both written under the assumption that we know "dark matter" exists... but we know no such thing. It is still a matter of much controversy (no pun intended).

We have various theories to account for the observations. Among them the most popular of the string theories, which support the existence of dark matter. But on the other hand, there have been a number of recent findings that call "string theory" itself into strong question. Perhaps even rendering it invalid.

Much hinges upon whether the true God particle, the gravitron, really exists. If it does, it would shake up the standard model. If it doesn't, it would shake up the standard model.
Safest right now is to sometimes believe in it, and treat its existence as as unfalsifiable as God, while having a drink at the multi-dimension (including string theory) bar.

In short, we are a tad short on understanding how mass and gravity really interact, and the implications. Which dark matter hinges on - both whether and what.

Re:well that article sucks (3, Informative)

khayman80 (824400) | more than 2 years ago | (#40561203)

String theory isn't testable using current technology, but it's largely unrelated to dark matter. On the other hand, we've already discussed [slashdot.org] some of the actual evidence for dark matter. This new paper [arxiv.org] seems (to my non-cosmologist eyes) to be very rigorous. Among other checks, they extensively searched parameter space to exclude the possibility that standard NFW dark matter halos were being mistaken as a filament. The nearly head-on alignment of these two galaxies is fortunate, and the authors deserve credit for noting that it improves the signal-to-noise ratio of the gravitational lensing signal.

Re:well that article sucks (1)

Jane Q. Public (1010737) | more than 2 years ago | (#40561249)

Hi, Khayman80. Haven't heard from you in a while.

However, there has been much work being done on both "sides" of the matter, and I really don't feel I have time to get into a detailed discussion of the matter right now. But there have recently been findings that seriously call string theory into question, and in turn, that somewhat weakens the arguments for dark matter.

I'm not saying that anything is conclusive in either direction. But I sense the pendulum swinging...

Re:well that article sucks (1)

Jane Q. Public (1010737) | more than 2 years ago | (#40561265)

"String theory isn't testable using current technology, but it's largely unrelated to dark matter."

Apologies, I did not read this quite right the first time, or I would have answered it.

Yes, indeed, string theory is one of the pillars upon which dark matter theory is formed. It may be possible for it to exist without "strings", but in most current models they are inextricably intertwined. I.e., string theory does not depend upon dark matter theory, but dark matter theory (most models, anyway) very much DO depend upon string theory.

So anything that is evidence against string theory, is also an argument against MOST dark matter models as well.

Re:well that article sucks (1)

khayman80 (824400) | more than 2 years ago | (#40561281)

Citation?

Occam's Razor - Dark matter is nothing special (-1)

Anonymous Coward | more than 2 years ago | (#40559049)

I'm going to have quite a chuckle when scientists finally figure out that "dark matter" is literally what the name is. It's just normal matter that is not lit up from stars or other sources of light/energy.

It's massive amounts of regular matter that happened to arrange in such a way that stars didn't form. The actual interesting details will be exactly what type of matter and circumstances cause this to happen.

Re:Occam's Razor - Dark matter is nothing special (4, Informative)

jouassou (1854178) | more than 2 years ago | (#40559161)

This has already been considered [wikipedia.org] , but the current cosmological models and experimental evidence requires that the majority of dark matter be non-baryonic, i.e. composed of particles that are incapable of forming atoms and thence stars and planets.

Re:Occam's Razor - Dark matter is nothing special (1)

cameloid (120654) | more than 2 years ago | (#40559415)

My grasp of science is somewhat tenuous at best, but wouldn't all matter collapse into a common gravitational center?

For example, wouldn't a nebula-sized cloud of free electrons still collapse under their gravitational influence?

Re:Occam's Razor - Dark matter is nothing special (0)

Anonymous Coward | more than 2 years ago | (#40559945)

Going right out on I-am-not-a-astrophysicist limb here, but since the electrons are all negatively charged they would repel each other and isn't gravity the weakest force? Nevertheless I'm probably completely wrong and I think your question is still basically a good one. Doesn't matter lead to gravity the way love leads to marriage?

Re:Occam's Razor - Dark matter is nothing special (2)

c0lo (1497653) | more than 2 years ago | (#40560343)

Doesn't matter lead to gravity the way love leads to marriage?

Indeed, once married, gravity doesn't matter any more, with pregnancy, mortgage, kids' school, etc becoming more critical. Gravity starts to matter again closer to retirement age, but then manifests itself more like a burden.

Re:Occam's Razor - Dark matter is nothing special (1)

Doc Ruby (173196) | more than 2 years ago | (#40560219)

They are also under the influence of all the masses around them for their entire existence, like everything else. That's why all the Universe's matter is not clumped together in an infinitely massive, infinitesimally small point, but is spread through the Universe in wisps, clumps and intertwined folds. They're also subject to electrostatic repulsion, and the effects of the other fundamental forces, among the rest of matter, space, energy and other forms of what exists not yet categorized.

Re:Occam's Razor - Dark matter is nothing special (4, Informative)

Jane Q. Public (1010737) | more than 2 years ago | (#40561013)

"For example, wouldn't a nebula-sized cloud of free electrons still collapse under their gravitational influence?"

Hell, no. Gravity is orders of magnitude weaker than electrical repulsion. A cloud of electrons would disperse, not coalesce.

Gravity is even weaker than the so-called "weak" force in quantum physics. It is the weakest of all.

Except we'd still see evidence (5, Informative)

Immerman (2627577) | more than 2 years ago | (#40559235)

Well, except that if 80% of the mass in our galaxy was simply non-luminous, we'd still see the "haze" from it, just as we can see evidence of the existing hydrogen haze by it's characteristic absorbtion spectra, especially when starlight passes through nebula where the diffuse matter density is extremely high. Perhaps the vast majority simply formed gas giants and the like that were two small to "ignite", recent evidence does suggest wandering planets may be far more common than star-bound ones, but to get the 5:1 ratio still we'd be talking about 5000 Jupiters for every sun, and the sun is actually pretty tiny as stars go - with that many dark planets whizzing around it seems likely we'd see some evidence of them, likely of the frequent "Gas giant zooms through solar system, multiple planetary orbits disrupted, news at 11" sort. If the planets were smaller the "invasions" would be even more frequent, and if they were much larger (we're not sure of the exact limit) they'd spontaneously ignite

Then again - if using general relativity rather than Newtonian gravity actually does explain the odd rotational characteristics of our galaxy without reliance on massive amounts of additional matter then you may be right. There's still things like the Bullet Cluster that show evidence of something very weird going on though - the gravitational lensing seems to have become partially disconnected from the visible matter - if "dark matter" was simply non-luminous you would expect it to still have distribution and gravitational-collision properties similar to the glowing stuff, which is not the case there. Whatever is causing the lensing is behaving in a manner fundamentally different than the matter we can see, in fact it appears to be largely unaffected by the collision at all, which would seem to at odds with many "simple" dark matter theories as well (i.e. it's like normal matter, except light passes right through it).

Re:Except we'd still see evidence (3, Interesting)

Areyoukiddingme (1289470) | more than 2 years ago | (#40559463)

It seems to me that conclusions based on lensing effects are making a rather large assumption about the homogeneity of both interstellar and intergalactic space. The interstellar medium especially is supposed to be composed of so many atoms per cubic meter, and the assumption is those atoms are almost exclusively hydrogen and are evenly distributed

That may be an unwarranted assumption.

We've been staring at the sky for a long time now, but only recently have we been doing very large sky surveys, and only very recently have we had the processing power available to do something useful with wide swaths of that data at once. Seems to me there might be some Ph.D's to be had in using data from things like the Sloan Sky Survey to try to validate assumptions about the interstellar medium in greater detail. There may be thin filaments (on interstellar scales) of finely distributed matter that are denser than the overall medium. Or less dense. Or clumps. Nebulas are typically very diffuse. Might it be possible for there to be nebula-like formations that are even more diffuse? So diffuse that they appear largely transparent to most frequencies? So diffuse that their only affect on light is lensing?

I remember astronomers locating nebulas that were previously invisible because they don't emit visible light, but do emit in other parts of the spectrum. The explanation was they are older, cooler formations. But they don't just vanish as they continue to age. That gas is still around, getting ever cooler and more diffuse. Considering how much nova and supernova debris we've already identified in the galaxy, it doesn't seem too big of a leap to consider the long term (as in gigayears) ramifications of nova debris on the general interstellar medium.

Re:Except we'd still see evidence (2)

Doc Ruby (173196) | more than 2 years ago | (#40560231)

Why do you think that astrophysicists assume that the matter lensing the light is uniformly distributed? They're the most sophisticated experts in the actual distribution of the matter, which they say is uneven.

Re:Except we'd still see evidence (1)

Rich0 (548339) | more than 2 years ago | (#40559467)

in fact it appears to be largely unaffected by the collision at all, which would seem to at odds with many "simple" dark matter theories as well (i.e. it's like normal matter, except light passes right through it).

How is that at odds?

When you grab a door knob, why don't your fingers pass right through it? For that matter, why doesn't your hand just fall apart, or gravitationally collapse into a black hole?

The answer is that the electrons in your hand are repelled by the electrons in the door knob, and that the various atoms in your hand are held together by chemical bonds, but repel each other as well to hold themselves roughly rigidly in place.

Why does that happen? Electrons interact with the electromagnetic force, which means they interact with photons.

Now, suppose you had a type of matter that photos passed right through, like dark matter. That makes it likely that this matter does not interact via electromagnetism either, which means that it is not repelled by other matter and may be able to pass right through it. Or, maybe it interacts in other ways, but those ways have much smaller cross-sections of collision. Remember that almost all of the space in an atom lies between the electrons and the nucleus. If the cross-section of matter were a nuclear radius and not an atomic radius then if you had a gas there would be FAR fewer collisions.

I'm sure a physicist could give a better explanation, but it isn't surprising at all that a dark form of matter that does not interact with photons would also behave VERY differently when it comes to collisions with other forms of matter, or perhaps even with other forms of dark matter.

Re:Except we'd still see evidence (2)

Immerman (2627577) | more than 2 years ago | (#40559683)

At odds because when you're talking about colliding galaxies you're not talking about physical collision - the instances of individual stars actually colliding with each will be fairly rare - the collision is gravitational - stars pass by each other and mutually deflecting their paths, exchanging momentum in the process. Since such collisions are almost entire gravitational you would expect "simple" dark matter to behave in a similar manner. Photon pressure would have some effect, but probably not much, comparatively (though I could be wrong about that). I suppose perhaps magnetic forces might contribute noticeably if the stars past close enough to each other, though that inverse-cube falloff is a killer. Even a few percent of extra "drag" though might be enough to account for the discrepancy, I'm not really sure just how big it is.

Re:Except we'd still see evidence (0)

Anonymous Coward | more than 2 years ago | (#40560047)

It's because electromagenitism makes ordinary matter a) clump together, giving greater mass concentration in certain places like stars and b) can lose energy via electromagnetic radiation, and thus tends to clump in the centre or disk of the galaxy.

Since dark matter doesn't clump, it provides a uniform gravitational field throughout the galaxy of the halo and siginificantly beyond. Since there are no "dark" star to "dark" star interations as you'd see with ordinary matter, the dark matter is basically collisionless in galactic mergers.

You are fucking stupid/ignorant (1, Insightful)

Anonymous Coward | more than 2 years ago | (#40559441)

You must be a Fox News watcher.

Because you are so fucking arrogant as to think that you who obviously don't know shit about cosmology, astronomy, or astrophysics, would think that you know better than people who have been working for years, some their entire lifetime. Seriously if you had one fucking class on the subject you would know that cold regular matter absorbs light, so it can still be directly observed like a shadow.

So how about stop assuming that you know more about physics than the physicists, and try and learn something?

Re:Occam's Razor - Dark matter is nothing special (-1, Flamebait)

Doc Ruby (173196) | more than 2 years ago | (#40560209)

You're stupid.

How do they know it's dark matter? (1)

Immerman (2627577) | more than 2 years ago | (#40559059)

Okay, so even assuming the light-bending is real, what's their evidence that it's dark matter and not simply non-luminous normal matter? I can see something like the bullet cluster strongly supports dark matter versus alternative theories (e.g. using general relativity rather than Newtonian gravitational theory apparently explains the odd galactic rotational characteristics ) since the vast bulk of matter appears to have passed through without interacting. Then again , should the dark matter have "collided" almost as hard? It's not like we're talking about direct star-on-star collisions, it's all gravitational interaction, in which case dark matter should play by pretty much the same rules, assuming it's actually matter.

Re:How do they know it's dark matter? (5, Interesting)

lgw (121541) | more than 2 years ago | (#40559165)

Non-luminous normal matter absorbs light (and so becomes luminous normal matter evenutally, at least at some frequency).

BTW, the confirmation for dark matter vs other theories for galaxy rotation came from the WMAP [wikipedia.org] data. IIRC, about 80% of the early matter of the universe was shown to be somehting that interacted gravitationally, but did not interact with light (or electrons). The actual % of dark matter measured matched the amount predicted by the dark matter hypothesis for galaxy rotation rates, which is a pretty convincing confirmation IMO.

Re:How do they know it's dark matter? (5, Insightful)

Immerman (2627577) | more than 2 years ago | (#40559603)

Actually, it generally goes the other way - when a non-star initially forms it will be hot, and has to radiate all that energy away, becoming less bright until it eventually becomes effectively non-luminous. Starlight simply isn't dense enough to significantly heat anything substantially - it will be radiated away as fast as it gets absorbed, and that's *way* below what we can currently detect. Our telescopes may eventually become sensitive to detect such MACHOs directly, but they're not there yet. And micro-lensing studies seem to limit them to comprising roughly the same amount of matter as luminous objects unless they're predominantly >100 solar masses (which would likely tend to be radiant) or less than Moon-sized, in which case there would need to be so many of them that they would likely be passing through the solar system on a fairly regular basis, which we haven't seen.

If we're talking about stuff in intergalactic filaments though - well, they make interstellar space look positively dense, anything non-luminous would be so close to absolute zero, and so far away, that it would be effectively invisible unless directly in front of something. And it would have to be in a pretty frakking dense cloud to significantly blot out a galaxy Remember that as a wave light will bend around any object in it's path, not much, but slightly (this effect is completely separate from gravitational lensing) and over intergalactic distances that's enough that the "cumulative effects" of a million individual objects each blocking one millionth of the "disc" of a distant galaxy will be far less than you would expect.

As for galactic rotation and WMAP - there is correlation there, I'll give you that, and when two independent measures give you similar results you should probably sit up and take notice. However, when something like the general-relativity explanation for galactic rotation speeds comes along and says - "Hey, you know that really weird behavior we couldn't explain that made us come up with a really bizarre theory to explain? Well we finally have the computational power to run the analysis using the currently accepted theory of gravity instead of the much simpler but known-flawed centuries old model, and everything works out pretty close to what we actually see." Well, that should make you take notice as well. In fact that should make you sit back and take a long hard look at all your "cosmological gravity weirdness", because most of that happens on a scale where galactic distances look positively local, so you'd expect the discrepancy between instantaneous Newtonian gravity and GR gravity to be even larger.

Astronomy is a somewhat shaky field - all theories are fundamentally untestable - all you can do is look out at the universe and try to find phenomena that seem to support or counter theory, but in doing so you're making numerous assumptions about what exactly you're looking at to begin with, and assuming it behaves in a manner consistent with other widely accepted but still fundamentally untestable theories. Now that technique is surprisingly effective, but it is vulnerable to flaws in analysis, especially when much analysis is based on something that is known to be inaccurate (Newtonian gravity) because the alternative is too computationally expensive to use.

Re:How do they know it's dark matter? (1)

Jane Q. Public (1010737) | more than 2 years ago | (#40560833)

"Well we finally have the computational power to run the analysis using the currently accepted theory of gravity instead of the much simpler but known-flawed centuries old model, and everything works out pretty close to what we actually see."

Sounds like you are referring to MOND, or something like it?

Re:How do they know it's dark matter? (0)

Anonymous Coward | more than 2 years ago | (#40560941)

He indicated elsewhere in the post that he was referring to General Relativity, not MOND. (It would be a bit odd to refer to MOND as "the currently accepted theory of gravity", I think - I believe MOND is still considered a hypothesis rather than a theory, even by the people fronting it.)

Re:How do they know it's dark matter? (3, Funny)

Anonymous Coward | more than 2 years ago | (#40561151)

Astronomy is a somewhat shaky field - all theories are fundamentally untestable - all you can do is look out at the universe and try to find phenomena that seem to support or counter theory, but in doing so you're making numerous assumptions about what exactly you're looking at to begin with, and assuming it behaves in a manner consistent with other widely accepted but still fundamentally untestable theories. Now that technique is surprisingly effective, but it is vulnerable to flaws in analysis, especially when much analysis is based on something that is known to be inaccurate (Newtonian gravity) because the alternative is too computationally expensive to use.

Makes me feel better about studying Economics

Re:How do they know it's dark matter? (0)

Anonymous Coward | more than 2 years ago | (#40559173)

Not sure if applies in this case, but generally this sort of thing is ruled out under the category of "MACHOs" - see wiki: here [wikipedia.org]

Easy, the sampled it (4, Funny)

tlambert (566799) | more than 2 years ago | (#40559225)

And it turned out that it was made of what we long suspected the mising mass of the universe wa composed of: AOL discs.

Re:Easy, the sampled it (1)

axlr8or (889713) | more than 2 years ago | (#40559381)

Should have been modded funny u know. I mean. I used to work for a paper company in those days and we would have scads of those things. They were the 1.44 flops. I'd take em home, flip the tab and rip the stickers of of them. Never ran out of disks heheeh.

This is all very well ... (0)

Anonymous Coward | more than 2 years ago | (#40559153)

... but why aren't these scientists trying to find something useful, like where the hell all my odd socks go?

Re:This is all very well ... (1)

Doc Ruby (173196) | more than 2 years ago | (#40560203)

They totally convert into the equivalent mass of ballpoint pens you have that you have but never bought.

Re:This is all very well ... (1)

Bill Currie (487) | more than 2 years ago | (#40560723)

More specifically, non-working ballpoint pens.

These people are just not up on the classics. (5, Funny)

the eric conspiracy (20178) | more than 2 years ago | (#40559155)

Dark Matter was proven decades ago as this following article demonstrates.

Bell Labs Proves Existence of Dark Suckers

For years it has been believed that electric bulbs emitted light. However, recent information from Bell Labs has proven otherwise. Electric bulbs don't emit light, they suck dark. Thus they now call these bulbs dark suckers. The dark sucker theory, according to a Bell Labs spokesperson, proves the existence of dark, that dark has mass heavier than that of light, and that dark is faster than light.

The basis of the dark sucker theory is that electric bulbs suck dark. Take for example, the dark suckers in the room where you are. There is less dark
right next to them than there is elsewhere. The larger the dark sucker, the greater its capacity to suck dark. Dark suckers in a parking lot have a
much greater capacity than the ones in this room. As with all things, dark suckers don't last forever. Once they are full of dark, they can no longer suck. This is proven by the black spot on a full dark sucker. A candle is a primitive dark sucker. A new candle has a white wick. You will notice that after the first use, the wick turns black, representing all the dark which
has been sucked into it. If you hold a pencil next to the wick of an operating candle, the tip will turn black because it got in the path of the dark flowing into the candle.

Unfortunately, these primitive dark suckers have a very limited range. There are also portable dark suckers. The bulbs in these can't handle all
of the dark by themselves, and must be aided by a dark storage unit. When the dark storage unit is full, it must be either emptied or replaced before
the portable dark sucker can operate again.

Dark has mass. When dark goes into a dark sucker, friction from this mass generates heat. Thus it is not wise to touch an operating dark sucker.
Candles present a special problem, as the dark must travel in the solid wick instead of through glass. This generates a great amount of heat. Thus it can be very dangerous to touch an operating candle. Dark is also heavier than light. If you swim deeper and deeper, you notice it gets slowly darker
and darker. When you reach a depth of approximately fifty feet, you are in total darkness. This is because the heavier dark sinks to the bottom of the lake and the lighter light floats to the top. The immense power of dark can be utilized to mans advantage. We can collect the dark that has settled to the bottom of lakes and push it through turbines, which generate electricity and help push it to the ocean where it may be safely stored.
Prior to turbines, it was much more difficult to get dark from the rivers and lakes to the ocean. The Indians recognized this problem, and tried to
solve it. When on a river in a canoe travelling in the same direction as the flow of the dark, they paddled slowly, so as not to stop the flow of dark, but when they traveled against the flow of dark, they paddled quickly so as to help push the dark along its way.

Finally, we must prove that dark is faster than light. If you were to stand in an illuminated room in front of a closed, dark closet, then slowly open the closet door, you would see the light slowly enter the closet, but since the dark is so fast, you would not be able to see the dark leave the closet.

In conclusion, Bell Labs stated that dark suckers make all our lives much easier. So the next time you look at an electric bulb remember that it is indeed a dark sucker.

Re:These people are just not up on the classics. (4, Funny)

hawguy (1600213) | more than 2 years ago | (#40559223)

I don't know if I believe you about the dark suckers, but I know how to prove that Dark Matter exists - just redirect one of the mars probes to go visit this dark matter filament and bring back a sample. The Curiosity Rover already has a drill, which would aid in extracting the matter. It should be a simple matter of stellar mathematics (provided that we're willing to wait a bit longer) to set it on a course to the filament. On the way there the rover can be reprogrammed to autonomously land and extract the matter. Since it will be a bit further from Earth than it was designed for, it might be out of radio contact so it will have to be self sufficient.

Easy-peasy, in a "few" years we could be examining samples from this dark filament here on earth.

Re:These people are just not up on the classics. (0)

wierd_w (1375923) | more than 2 years ago | (#40559361)

Uhm?

This filament is between two neighboring GALAXIES.

Compare:

fastest manmade objects in existence: voyager space probes.
Probes have been in flight for over 40 years. They are just now entering the interstellar medium.

At this rate, it would take millions of years for one of these probes to reach the fillament. One way. They are hundreds of thousands of lightyears away.

The mars probes' batteries would be dead long before reaching the filament, and humanity would have evolved into a new lifeform in the intervening time.

"A few years" is a literally astronomical understatement.

Re:These people are just not up on the classics. (0)

Anonymous Coward | more than 2 years ago | (#40559383)

"A few years" is a literally astronomical understatement.

Thanks for explaining the joke.

Re:These people are just not up on the classics. (0)

Anonymous Coward | more than 2 years ago | (#40559409)

Anybody else hear that "whoosh" sound?

Re:These people are just not up on the classics. (1)

hawguy (1600213) | more than 2 years ago | (#40559593)

Uhm?

This filament is between two neighboring GALAXIES.

Compare:

fastest manmade objects in existence: voyager space probes.

But the lightbulbs-as-dark-suckers theory is still correct, right?

P.S. You're off by a few orders of magnitude - these galaxies are 2.7 billion light years away, if Voyager 1's 10 miles / second speed is comparable (currently the fastest speed from the sun as any manmade object though I suspect we could do better if we were only interested in launching the probe into interstellar space), it would take around 5 x 10^13 years for the probe to reach the galaxy.

I don't know about you, but I've already set my DVR to record that moment just in case I'm not home when it happens.

Re:These people are just not up on the classics. (2)

Jane Q. Public (1010737) | more than 2 years ago | (#40560895)

"I don't know about you, but I've already set my DVR to record that moment just in case I'm not home when it happens."

Be sure to go into the "advanced" menu and override the default exponent.

Re:These people are just not up on the classics. (0)

Anonymous Coward | more than 2 years ago | (#40560713)

Along the same lines, are you aware that chips run on magic smoke?

The proof is that if you let the magic smoke out, the chips stop working.

Bigger than the Higgs (4, Interesting)

Nom du Keyboard (633989) | more than 2 years ago | (#40559273)

I'd call this bigger than the Higgs.

Re:Bigger than the Higgs (0)

Anonymous Coward | more than 2 years ago | (#40559359)

I'd call it smaller. We already knew dark matter existed. We've already seen it. And we were pretty sure it existed in these filaments, it was just hard to see. We still don't know what the stuff is, though.

Re:Bigger than the Higgs (0)

Anonymous Coward | more than 2 years ago | (#40559815)

Regarding the (supposed) Higgs and dark matter filaments, these are two important discoveries within completely different fields of endeavor. They cannot and should not be ranked in order of "bigness."

However, since the new Higgs-like particle may eventually lead to modifications of the Standard Model -- modifications which may be able to account for Dark Matter -- the two discoveries are very much complementary.

Re:Bigger than the Higgs (1)

Doc Ruby (173196) | more than 2 years ago | (#40560197)

Another type of matter that differs in that it doesn't absorb or emit light, but is detected by the effects of its mass, is bigger than the particle that implements mass itself? A type of matter is bigger than the the instance of a fundamental parameter of existence? No it's not.

Re:Bigger than the Higgs (0)

Anonymous Coward | more than 2 years ago | (#40560265)

I got it Nom...

For the two respondents without a sense of humor, Higgs is subatomic partical, a bunch of darkmatter occupying an area larger then star-systems is bigger, obviously.

Re:Bigger than the Higgs (1)

Jane Q. Public (1010737) | more than 2 years ago | (#40560903)

"I'd call this bigger than the Higgs."

I'm not really sure about the scales here, but just off the top of my head, you could probably call this bigger than the Higgs by around 30 orders of magnitude.

Dark filament already obsolete. (0)

Anonymous Coward | more than 2 years ago | (#40559333)

I want to see a pig-tail bulb, one of those compact fluorescent-types with dark-matter instead of mercury, so when I flip on the switch, the room is plunged into darkness, even if it's noon and the drapes are open. That'd be cool for a darkroom or a home-theater. Especially useful if you can make a flashlight... excuse me, I mean a flashdark out of it, so you can blind people with darkness in tactical situations. You can blind them with super-bright light, but on a dark night, it kinda gives away your position to anyone not close-enough to blind. A flashdark would not, it would just suck up the beam from the sentry's flashlight, maybe even making him think it had gone out. As he points it at his own face, tapping it against his free-hand, you point the flashdark away from him, and he blinds himself. Then you use your flashdark again to sneak past him while his eyes are dazzled and he's drooling incoherently (yes, you can be messed up enough to pull that off, but it takes WORK,) trying to figure out why his own flashlight stabbed his eyes out.

Tip-toeing quietly, you can slip right by undetected. Pretty cool application of new discoveries, wouldn't you say?

This is truly exciting. (2)

axlr8or (889713) | more than 2 years ago | (#40559335)

In a world where people are only comforted by thinking they understand how the universe works I'm totally fascinated by the unexplainable. It boggles my mind that people couldn't believe in 'invisible' mass. Furthermore, I look forward to what organisms may exist in that phase. Maybe Deadmau5's got it. Ghosts n stuff.

Re:This is truly exciting. (1)

Jane Q. Public (1010737) | more than 2 years ago | (#40560923)

"It boggles my mind that people couldn't believe in 'invisible' mass."

It should not boggle your mind, at all. Because it's not a matter of "belief" at all. It is a matter of evidence. And conclusive evidence is not there.

There are MANY very smart people who "believe" in that invisible mass. But they, themselves, know that belief is not the measure by which their work will be judged.

This is actually far more important (2)

WindBourne (631190) | more than 2 years ago | (#40559351)

Higgs was pretty much a given. All that CERN did was confirm it. OTOH, Dark matter occupies a large amount of the universe and yet, we have not found it. So, the question is, is this real?

Re:This is actually far more important (5, Informative)

b4dc0d3r (1268512) | more than 2 years ago | (#40560485)

Un-doing 7 well-deserved mod points to post this, so pay attention. Higgs was not a given. A particle in the same range without the ability to generate the Higgs field was also a possibility. The team explicitly stated that further confirmation is needed before they can say they found Higgs, or a Higgs-sized particle that does not do the things Higgs Boson is supposed to do.

It is still up in the air as to whether we have a Higgs Boson, or a Higgs-less theory of mass. Obviously everyone is leaning towards Higgs because it matches predictions. But what if it is Higgs sized without having the correct properties? Then you're wrong, and also an idiot for assuming it is a given.

If we indeed found it, then you're a lucky guess at best.

I agree this is more important, but only because we have been zeroing in on a Higgs-sized particle for quite some time. Dark matter has been purely theoretical until now (and still this is only the first sighting, subject to review and revision as with all experimental results). More important because it's newer.

In truth, we won't know for a hundred years which is more important. If dark matter has been theorized since 1930's and we just confirmed it, it is no more important than such ideas as gravitational lensing which have been around for decades before being confirmed. We have known it for a long time, in other words. To me, more important would be strong evidence that a 90 year old hypothesis was completely incorrect and in need of revision.

Neither one of these, to me, beats a fat man finally seeing his toes after 30 years. He had a feeling they were there, and had been told as much, but to finally see them is a whole different ball game.

Re:This is actually far more important (2)

Jane Q. Public (1010737) | more than 2 years ago | (#40560945)

"Higgs was not a given. A particle in the same range without the ability to generate the Higgs field was also a possibility."

Thank you! You have just confirmed what I stated in the Higgs thread, for which I was modded "troll" more than once.

They Rolf Heuer said they are 5-sigma confident that they found a particle, which so far seems consistent with predictions about the Higgs. That is not the same thing as crying to the heavens that the Higgs has been found.

Re:This is actually far more important (0)

Jane Q. Public (1010737) | more than 2 years ago | (#40560953)

I don't think I know you, but we seem to think much alike.

Re:This is actually far more important (3, Interesting)

arth1 (260657) | more than 2 years ago | (#40561043)

Un-doing 7 well-deserved mod points to post this, so pay attention. Higgs was not a given. A particle in the same range without the ability to generate the Higgs field was also a possibility.

Correct me if I'm wrong, but I think a pairing between a Z and W boson was also considered a candidate.

And also if assuming the Higgs' boson, the question was whether it was in the 120-130 GeV or in the ~182 GeV range - the energy difference could have significant impacts on the standard model, especially in higher order Higgs (when it interacts with itself), but also in how rare the sub-particle would be, and in predicting where to find the last couple of missing particles (not counting the elusive Gravitron).
All in all, the LHC discovery, although predicted, is a great discovery that will give physicists data they sorely needed.

Dark matter? Not so much. We know there are unobservable gravitational effects, but we can't currently say what they are even if we can point to a place where they are. Nailing the Higgs' boson may, in the future, help with this, but not yet.

Our Universe Makes My Brain Hurt (5, Funny)

Greyfox (87712) | more than 2 years ago | (#40559781)

It's like a sophomore project in universe design class. A way-too-slow hard-coded top speed, lots of localized buffer overflows without proper error handling or anything (Too much mass in one place should at LEAST throw an exception,) particles popping in and out of existence all the time, and the whole thing is held together by duck tape and dark matter. Honestly, I might give this universe a "C"... if I was feeling generous.

Re:Our Universe Makes My Brain Hurt (1)

Doc Ruby (173196) | more than 2 years ago | (#40560181)

Another case of the professor's inability to understand his subject lowering an inventive student's grade.

Eheh (1)

SmallFurryCreature (593017) | more than 2 years ago | (#40561169)

So, you go tell the student that, the guy is unstable in the extreem! Wiped out an entire planet just because people wouldn't listen to him. Imagine what he do with a professor that gives him a C. Would be a sight to see. Preferably from another universe.

A big blow (0)

Anonymous Coward | more than 2 years ago | (#40560023)

To the morons that claim dark matter is just another search for the aether

Good for them (3, Funny)

PopeRatzo (965947) | more than 2 years ago | (#40560095)

Dark Matter Filament Finally Found

Now maybe they can help me find my keys.

Re:Good for them (2)

Jane Q. Public (1010737) | more than 2 years ago | (#40560971)

Yep. And as it turns out, they seem to be a billion or so light years away.

You don't own a ferret, by any chance?

Dark Energy? (2)

Doc Ruby (173196) | more than 2 years ago | (#40560175)

Some explanations of dark matter say that most of the gravitational effects are from dark energy, not condensed into matter. But if dark matter differs from other matter in that it doesn't absorb or emit light, how does dark energy differ from other energy? Energy doesn't absorb or emit light, so how is dark energy different? Unless they mean that it doesn't get absorbed or emitted as light, the way other energy does (ie. photon beams). Without that property it seems rather unlike other energy, enough that it's not really energy.

And if it is dark energy, then where is all the cold, dark info? The next more subtle form of existants.

drat (0)

Anonymous Coward | more than 2 years ago | (#40560189)

And I was so sure that it would be found between Rush Limbaugh's ears. Oh well.

font (0)

Anonymous Coward | more than 2 years ago | (#40560669)

If this one isn't announced in Comic Sans, this is the superior discovery

Supersymmetry (0)

Anonymous Coward | more than 2 years ago | (#40560671)

I was tempted to suggest that so-called "dark matter" might in fact turn out to be the supersymmetric twin of the neutrino. (Neutrino: nearly massless; practically no interaction with normal matter. Dark matter: entirely massive, practically no interaction with normal matter.)

Then I remembered that the velocity of a neutrino is nearly that of the speed of light, or the maximum velocity in this universe. Thus, I reasoned, the velocity of dark matter must approach zero.

This theoretical prediction has clearly been refuted by experimental evidence.

Oh, that and the fact that all varieties of neutrinos already have had their supersymmetric partners identified...

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>