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Dark Matter WIMP Detection Claimed
Scientists at the University of Rome claim they have discovered evidence for Weakly Interacting Massive Particles (WIMPs). Their paper will be presented on Friday, and of course the verification process will take a while. The claimed particles weigh as much as a nickel atom, and could turn out to be the dark matter that astrophysicists have sought for so many years. All you touch and all you see may be only 20% of the universe. Read the
NYTstory (free reg. req.) and then visit the
TBTFblog
for detailed information.
It is obvious that this "dark matter" is an attempt by the status quo to keep their controls on science. Science is ruled by an over conservative good old boys network who don't want to change teir minds about things they learned in school. This recognition of dark matter is further continuation of this network. If modern science weren't under the control of these people would quantum mechanics as we know it be taught? Probably not anymore, because we would have found a new theory about the universe that could explain things a little better.
All right, Mr. Scientist, since you seem to be such an authority on the universe I'm sure we'd love to hear your theories. Why is the idea that there's more than one kind of matter so far-fetched?
L : slashdolt
P : slashdolt
works fine. They'll probebly kill it soon ( like
they did for cypherpunk & cypherpunks ).
--= Isn't it surprising how badly I spell ?
The missing mass needed to close the universe has always been assumed, I've assumed, to exist in the form of either WIMPs or MACHOs (massive compact halo objects) or the Cosmological Constant. Interesting times when evidence for all three is strengthening at once. The current Science News features a solid survey of the unanimity the remarkable idea of an accelerating universal expansion has garnered in just two years -- so much so that the current best-guess value for the CC, the push factor, is engraved on a plaque at the top of the spiral "walk through time" in the new Rose Center (formerly the Hayden Planetarium) in NYC. And convincing evidence for the existence of MACHOs was presented at the recent Atlanta meeting of the AAS. (I'll have links for all these loose ends when the next TBTF issue comes out.)
Ahhhh! Someone accused someone else of not understanding how science works. I have a small amount of experience here.
Science works this way (compressed version): I say "Bullshit", you keep showing me evidence until I stop saying "bullshit".
The attitude to hold should be one of *utmost* skepticism. WIMPS are an extraordinary claim, and one should yell bullshit until we are shown extraordinary proof. I don't think the person you're replying to was dismissing at all. He was wagering.
I will raise him $50 that the study when released is shoved in a drawer and forgotten.
If tits were wings it'd be flying around.
Am I the only one that thinks "neutralino" sounds like an Italian food place in Switzerland?
"Come! Dine at Neutralino's, where your fettucini is always protected by our stricly anonymous dining laws!"
-LjM
Neutrinos have a mass of something like 1/1Bth of an electron. They've been detected in large pools of soft water. I'm just saying that I have a very difficult time believing that something with the mass of a nickel atom, can have less effect on the surrounding environment than a neutrino. Come on now, you have to admit, its pretty far fetched.
/. will believe that these particles actually do.
;)
I think this is a perfect example of science trying to fit things into place with a theory. There's nothing wrong with that, as long as the theory doesn't account for something thats easily explainable by something else. This whole dark matter issue is explainable by unseen dust, and unseen matter. We don't need to theorize about weak particles the size of nickel that weakly flow through the Universe, because there's nothing that truely tells us this.
Now I'm not saying its not possible. I just have an overwhelming feeling that the paper will be released. Physicists everywhere will say its bullsh1t, and we'll never hear about it again... with which half of
BTW, I have the fountain of youth. Its a combination of a couple off the counter drugs. I'll be releasing it in my paper Wednesday.
Thats my case
Thank you. Finally someone who sees it how it is. Everything they've stated is philosphical, with no evidence, just symptoms. They say they have something, but they haven't shown _anything_. Why would they wait for some convention to describe their technique, if they could dish it out _now_ and astonish the scientific community _today_. Makes me think they're looking for press.
I never said it wasn't possible, and I'm not accusing them of anything. What I'm saying is that I have an _extremely_ hard time believing anything _YET_. This is simply because they're showing us nothing.
PD apparently is the only one here who sees this as rhetoric. I'm yelling bullshit because we've _seen_ _nothing_. Yeah there are lots of amazing theories and ideas in the world. The rotational curve of galaxies being a result of WIMPs is one of them. I'd just say that they're due to gas and dust thats undectible because they've reached thermal equillibrium. The evidence atleast suggests that.
$50 says that the study is shoved in a drawer and forgotten.
I totally know about absorption and emission lines in spectra, and what they represent. I'm not attacking the physicists themselves as much as I am the actual publication on NYT website. If I had a nickel for everytime I noticed something that ws just blatently false in the media, I'd be rich as hell.
/. jumps the gun talking about how cool this is, etc, even though we've seen no evidence, other than what that article itself says.
;) It could be dead stars, or small rocks and dust, comets, planet-sized asteroids, etc. I agree with you that its fishy, but Physics, right now, at this moment suggests that its matter in its traditional form (atoms). Its scientificly unsound to say otherwise, especially when the NYT is attempting to report scientific break-throughs.
The issue is that half of
Based on that, I'd say there's no basis for it. The whole theory of WIMPs in general just seems a bit far fetched to begin with. Thats basicly all I'm saying. Everyone just feels the need to jump on my back when I say that I think its bs, because right now, I've read nothing that tells me otherwise.
I'm actually very interested in the whole topic itself. I'd like to see the unified theorem come to fruition. I'm just not going to let my hope talk me into believing something that as of this moment, has no evidence.
Thats pretty much my stance.
As for the absorption lines, gas isn't the only form of matter in the Universe
The term 'dark matter' is simply matter that we cannot see. When astrophysicists are looking for dark matter, what they're actually trying to do is see gas, dust and dead stars that are not luminous. Dark matter is not a different form of matter, its just matter that has settled into the 3 degrees Kelvin equilibrium of space, and is therefore undetectable, unless heated by an external force.
;)
"Though astronomers have been measuring the gravitational pull of the dark matter since the 1930's, they have never succeeded in detecting it directly."
I assume with this statement they're refering to the velocity vs distance from the center for stars in a galaxy. Its always been known that the fact that the stars in a spiral galaxy rotate with uniform motion, like a disk, simply because of the amount of dust and gas in between the stars.
If you ask me, I call this someones "what if" explaination, and attempted proof, that will quickly be disproved if it does in fact have any scientific basis. Of course, when this happens however, it won't make it to the presses
Sorry, couldn't help myself. I like physics, too.
Regards,
-BK
Chemical Blog
Absolutely - that's one of the reasons this is so exciting. As the other responder pointed out, this particle is weakly interacting and so we couldn't directly detect it, but it would show up as "missing energy". For instance, you could get a reaction at LHC on the lines of
proton + antiproton -> very energetic gluons -> squark + antisquark -> neutralinos + lots of other junk.
You could detect all of the other junk and measure its energy and momentum, and you'd see that there's a giant difference between that and the initial beam energy, so the difference must be particles that escaped your detection. Similarly you could measure the "missing charge" and so on, so you get a pretty good fix on what escaped.
The only catch is that 134GeV is actually about the absolute max that LHC will be able to see. The problem is that, while the interaction energy is about 2TeV (once everything's at full spin), the particles are protons and antiprotons. At these energies, you have to think of each of these as composite objects; bound states of three quarks (antiquarks) and a lot of gluons. The actual scattering is a quark off an antiquark, so each constituent particle has only about 1/7 of the total beam energy. On top of that, because of various conservation laws neutralinos (or any other SUSY particle) have to be created in pairs, so you need a lot of energy to do this.
But finding these particles (the buzzword is 'LSP,' Lightest Supersymmetric Particle) is one of the primary missions of LHC.
Yonatan
Several people seem interested in what dark matter is and whether its existence is a certain thing or a theory. So here's some stuff from the science end --
The matter you can actually see through a telescope is really only luminous matter; things which are directly emitting (a great deal of) light. Namely, stars, quasars, occasionally black holes (which are black but infalling matter creates huge X-ray jets) and things like that. Anything else, by definition, is "dark matter." (So by definition, you and I are made of dark matter - this is not generally that wierd a stuff)
The reason we know dark matter is there in large quantities is by measuring the motion of stars in galaxies and so on. Basically, we understand how gravity works pretty well (at least on astrophysical scales) and so by watching the motions and orbits of luminous objects, we can work backwards and find the distribution of mass in the universe. From this we find that only about 10% of all mass is luminous - the rest is "dark matter."
Now, it turns out we can find out substantially more about dark matter from these gravity measurements. (There are a lot of different kinds of measurements which I won't go into; suffice it to say that they all more or less agree) For one thing, we can tell how it clumps up, and from that deduce some things about its internal structure. For example, dark matter made out of heavy noninteracting particles (say about the mass of an iron nucleus) will move around very differently from dark matter made out of very light fast particles, which will move differently from large lumps of matter each about the size of a star, and so on.
The basic types of dark matter are:
Hot Dark Matter: (HDM) Small light particles moving about at close to the speed of light. Measurements suggest that there isn't much of this around, not enough to make a huge difference. Neutrinos would fall into this category.
Baryonic Cold Dark Matter: (Baryonic CDM) Heavy particles in the form of ordinary nuclei and atoms. Up to and including ourselves. This category also includes "MACHOs" (An acronym whose expansion I can't remember right now), which are essentially star-sized or bigger objects which we can't see. Brown dwarfs, large gas giants, and so on. Large dust clouds also fall into this category.
Non-Baryonic CDM: CDM means that the particles in question are heavy and so move much slower than the speed of light. Non-baryonic means that they're not made up of ordinary nuclei. This category includes what are called WIMPs (Weakly Interacting Massive Particles), which are any sort of big, heavy particle that doesn't interact much with other matter in the universe. (e.g., it can't have an electric charge, since that would make its dynamics very very unlike experimental data)
The reason WIMP searches are so cool is that any particle that turns out to be a WIMP will probably be very interesting in its own right. I can't explain all of the details in something of this length, but there is a symmetry called Supersymmetry (SUSY) which is postulated to exist. There are lots of good theoretical reasons to believe in it (for the technically minded: Grand unification doesn't work entirely right without SUSY, and you can't introduce fermions into string theories without SUSY.) and by now everyone is pretty much expecting to discover it experimentally soon; in fact, a discovery that SUSY doesn't exist would be even more interesting than a discovery that it does.
The reason I bring up this whole dreary story is that SUSY predicts that for every particle of ordinary matter (electrons, protons, photons, etc.) there is another related particle, its superpartner. A direct detection of a superpartner would be both a vivid confirmation of SUSY and incredibly useful experimental data about the structure and nature of the universe. (There are armies of physicists who are ready to strip every imaginable drop of information out of data right now. People have been waiting for this for a while.)
And lo and behold - the superpartner of the photon, called the neutralino, happens to have some properties that would make it a great candidate for a WIMP. It interacts very weakly indeed; for comparison, the Coulomb force between two electrons is proportional to 1/r^2, where r is their separation. The force between two neutralinos would scale something like e^(-r/r0)/r^2, where r0 is a characteristic distance on the order of perhaps 10^-20 meters. They're also stable - due to some conservation laws (analogous to conservation of electric charge, which makes circuits work) they can't decay into anything else, so once they're created, you're pretty much stuck with them drifting through the universe. And they're heavy - experimentally, their mass should be somewhere between 80-a few hundred GeV. (For comparison, a Hydrogen atom has a mass of just over 1GeV)
Now the Rome group is claiming to have detected WIMPs of masses somewhere between 52 and 134 GeV, which are candidates to be neutralinos. This will definitely spark some excitement and a lot of discussion. What happens next is that people are going to be reading this and arguing over every detail of their data analysis and so on, and other people will try to replicate their results. If this is confirmed, it represents a big step in understanding both the large-scale nature of the universe (WIMPs, and the nature and origin of dark matter) and its very small-scale structure. (SUSY, the fundamental interactions of matter)
OTOH, one shouldn't get too excited yet -- this represents an interesting result but it still has to go through a very rigorous checking and repeating process. It has happened (quite a few) times before that interesting signals have been observed which later turn out to be something very ordinary. It'll take some time to tell about this one, but hell - if it works, it's seriously neat.
Yonatan
-r
yes, or you may replace the 'www' part of the url with 'partners' to go directly there (as someone pointed out earlier today.) Or click here:
/ 021900sci-dark-matter.html
htt p://partners.nytimes.com/library/national/science
No annoying registration...who would've thought it would be that easy?
numb
I'd also like to see their report, but their server did not respond. The average NaI detectors is the equivalent of a 486 in the computer world. I wonder if that's what their web server is. Must be slashdoted.
Good luck to them.
Maybe I can get some money to see if any light really does come out of black holes. $1,000,000 and a few years later i'll be able to publish, add a banner ad to my homepage, and laugh as it gets slashdotted, carrying me to financial indepedence.
Drag n' Drop DVD Recommendations
Not valid. Scientists have found antimatter, played with it, and still needed to look for dark matter.
Bzzt. Wrong. Antimatter has negative charge, not negative mass. Matter with negative mass is something else entirely, and is responsible for antigravity.
---
Oper on the Nightstar
All that you see and touch is only a tiny fraction of the Universe.
Because there's also all that you taste, feel, love, hate, distrust, save, give, deal, buy, beg or borrow or steal, create, destroy, do, say and eat; everyone you meet, all that you slight, and everyone you fight, all that is now, all that is gone and also all that's to come.
And most impotantly, it must be remembered that this only the sum of everything under the Sun.
The Sun, you see, is eclipsed by the Moon, which as everyone knows is all dark, so all that you touch and see is more like only %0.083333333333333333 of the total mass of the Universe. Maybe less.
Here's the abstract, and here's the full preprint paper. It's an interesting, if quite densely technical, read.
Quantum mechanics: the dreams that stuff is made of.
According to the TBTF log, a neutralino is it's own anti-particle, which means that they destroy themselves upon contact and emit a gamma ray. If there is approximately 1 of these WIMPs per teacup-full of space, why haven't we seen these gamma rays from random collisions? And it seems that through random chance, the dark matter in the universe would be slowly disappearing (unless they're being formed all the time). Granted, they're tiny and weakly interacting, but still....any thoughts?
The San Fransisco Chronicle has an article, the paper itself is located at www.lngs.infn.it.