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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.
dark matter is cool
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 you touch and all you see may be only 20% of the universe.
All you see, all you feel. All you buy, beg borrow or steal...
:)
Sorry, Couldn't help it.
Bart G
How much would a pound of it weigh?
My ass is filled with dark matter and IT WON'T COME OUT!!!!!!!
A pound. Duh.
The key here is weakly interacting. Which means (unlike some threads are confusing the issue), this kind of dark matter is not just "not luminous", but does not interact with normal matter very well or often, making it wickedly difficult to detect.
:)
As to density, the galaxy (including our planet and you and me) is said to exist in a cloud of WIMPs with a density of about 1 particle per teacup, and that considering we're moving through the (assumed to be stationary) cloud at 140 miles per second, about a billion of these particles are passing through us every second. And they interact only weakly and seldom, so you probably don't notice.
Incidentally, each one of these is supposed to have the mass of a nickel atom, which is pretty damned heavy compared to elementary particles, so it remains to be seen whether this is a new kind of elementary particle or a composite of elementaries that magically become a WIMP. (Maybe this has already been theorized, I don't know.)
Ja, ne...
So, for the sake of argument lets assume that WIMP's exist and there are billions of them flying through us every second. Could this be possibly used in an outer space environment as a "push-off" force(if they could get them to react with some other matter consistently) and thus allow for a usable and stable "space-drive"? me, myself, and why?
Get out your check book.
Oh, wait. It's really expensive.
Who are you to whine, that other people's money isn't spent the way you particularly want it.
If you really want the SSC, spent with government money, you'd best work to make it a political issue.
you are a moron, please shut up.
so because i cant "feel or touch" things like x-rays they must be 'unconsequential' right? idiot
It is obvious that this "God" is an attempt by the status quo to keep their controls on religion. Religion is ruled by an over conservative good old boys network who don't want to change teir minds about things they learned in the Bible. This recognition of "God" is further continuation of this network. If modern religion weren't under the control of these people would creationism 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.
"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.....carrying me to financial indepedence"
yea astrophysicists are just rolling in it. every time i see someone in a BMW or mercedes i think to myself, gee....must be another one of those fabulously ritch and glamourous SCIENTISTS.
Don't you watch Futurama?
Dark matter is used for space ship fuel!
Remember, every pound of dark matter weighs over 1000 pounds!
While this discovery is certainly a milestone in astronomy, I would like to see more research done on the Weightless, Ubiquitous Shapeless Substances, or WUSSes. This material has eluded astronomers for ages. WUSSes, unlike WIMPs, are located within the earth's atmosphere as well as in outer space. Whereas the WIMPs weigh at least 50 times as much as a proton, WUSSes are so tiny that like electrons, they are almost weightless.
It is unknown what purpose WUSSes serve in the universe, although we do know that they are omnipresent. Hopefully one day we will know what they are there for.
I've met some pretty fucked up people from Sweden
It suprises me how many people just don't see! dark matter is "the force". I fear with this discovery jedi knights will become common amongst homosapiens... It's a pitty really. I can just see it now,.. the fat epidemic gets worse as people just utilise dark matter to do their bidding.
There's actually a competing MACHO theory that says that so-called massive compact halo objects (MACHOs) are responsible for the missing matter. I swear I'm not making this up.
Of course not!
First of all, sound isn't matter, it's the vibration of matter. Second, emotions are merely electrical connections being closed in your brain. One might even call us huge chemical processes. Lastly, dark matter is not the color black, or rather the absence of any photons reflecting off of a surface. Please use your brain before posting stuff that could be made into a big book titled "The Big Book of Inaccurate Information". Hmmmm. Maybe you should, it'd be a big seller among managment.
If everyone was calling me a WIMP, I wouldn't want to interact with them either.
As for being so massive, well obviously all this teasing and being an outcast will lead to overeating.
yeah right, perhaps instead, someone noticed no light was coming back... black as in the absense of light (no photons bouncing back? dark as in a room with no light, nothing to see? surely not
whats with all the reverse discrimination? if something is "black" or "dark" it has to be a racial thing, huh?
but wait, didnt hawkings prove that radiation _is_ emmited from "black holes" making them _WHITE_ holes?
oh... i forgot... that makes them good again... for white holes can convert matter to energy, while black holes just suck things in - never to be seen again... which makes them useless wastes of matter and energy...
i think we should enslave them, use them for travel, we could force them to power our ships by using the gravitational pull to sling us around and propel us across the interplanitary "ocean", much like slaves were used to power our ships in ages past and gone...
perhaps then the racial point would be justified.
They don't contribute much the the mass of knowledge on Slashdot, most just lurk, yet they collectively consune most of the bandwidth!
No fucking cookies required either. I eat enough cookies - no need to get the 'puter 'dicted too.
I hope you're not dumping on Linus Pauling, 'cause if you are... FUCK YOU!
If "weakly interacting massive particles" are WIMPs, then does that make ordinary "greatly interacting massive particles" GIMPs??
Isn't black the full absorption of photons by an object? I guess that would mean they don't bounce off it, but when you see color that's cause photons are absorbed, then re-emitted at all the other spectra except the color seen. Something like that.
Does anyone remember the name of the book and the author where devils and demons live in underground caves and tunnels? I just can't remember it myself, please help.
You might want to try actually learning something about dark matter before posting your gibberish. The fact that the "dark" in "dark matter" reminds of the color black and by consequence black holes does not neccesarily imply that there is any relationship between the two types of interstellar objections. Dark matter is just like normal matter, with the exception that it is almost invisible to our detectors because it has very low reflectivity (aka. albido) and transmittivity.
Right. And Rocks Don't Fall From the Sky, either.
The scientific community is full of skeptics - this can be good, but it can also hold back progress. Why don't you go read their report (it is posted, after all, on their page). See for yourself what they did.
Why do you have this idea that heavy things can't be weakly-interacting? There's no physics reason why not, is this just you putting your own "intuition" over the expertise of professionals? This would be about par for the course for the usual Slashdot egomaniacs.
The weak-coupling which makes them hard to detect would presumably also mean that they don't clump together to form rocks or whatever. They just go through each other too.
And all this time I thought X was the original dark matter WIMP.
If true, it would be possible to create the predicted WIMP with a particle accelerator. The problem is that such particles are very hard to detect. Even if one was created, it would probably go unnoticed.
Actually, the M-M experiment didn't disprove the existence of the ether, it merely proved that it was undetectable (By that technique).
It's worth pointing out than _anything_ that is described as the medium that light travels through _is_ the ether (Either light travels through a medium or it doesn't - if it doesn't, then what governs the speed it travels? If light is not travelling through anything, why should there be a limit on its speed?), and if such a thing were shown to exist it would cast doubts on Relativity, given that the non-existence of the ether is one of its chief assumptions.
I suggest people read " http://www.viconet.com/~retic/hoax0.htm " for more on this.
It could be argued that the strong U.S. military (including our nuclear arsenal) has kept us out of major conflicts since WWII and has largely helped ensure no other "total war" scenarios have occurred. If the ensuing stability were responsible for the unprecedented period of peace and economic growth, and a case certainly can be made that this is so, then this has had the secondary effect of sending more money into basic science (allowing us to "gain quite a bit of knowledge about the world we life in") than may have occurred had we had a WWIII and WWIV in the last 55 years.
I'd suggest you rant about entitlement spending instead. It's a bigger "black hole" for public money than military spending. The military actually invests a portion of its revenue in R&D science, and the money being spent on ASCI and Science-Based Stockpile Stewardship does have spinoffs of considerable value to the rest of the scientific community.
Correct me if I'm wrong, but isn't this still only on paper? Has anyone actually observed this?
Moderate this Funny, and moderate my comment Ass-kisser.
Does anyone know why the WIMPs wouldn't be traveling with the earth? It sounds like the experiment was designed to measure a difference created by the movement of the earth, but wouldn't the WIMP's orbit in similar ways to normal matter?
It doesn't matter what you want to postulate as the "dark, normal matter" -- it's well-known that there simply can't be that much normal matter in the Universe.
It works like this: we can calculate the amount of mass by observing the rotation curves of galaxies, and by measuring the motions of galaxies in clusters and superclusters. That gives us about 30% of the mass required for a flat universe (the rest is presently thought to be the Cosmological Constant, but I won't go there right now).
We still don't know what that mass is composed of... But we can also calculate the relative amounts of hydrogen, deuterium and helium created by the Big Bang (there was essentially nothing else categorized as "normal" matter which the Big Bang created) -- and the numbers that fall out tell us that "normal" matter (often called "baryonic matter") is only a fraction of that mass detected by galactic motions. If the Big Bang created more normal matter, we'd see a universe which looked very different than it does.
So SOMETHING ELSE -- not dead stars, not dust -- something which isn't baryonic matter at all, has to make up the majority of the mass we can see is there. Neutrinos (which apparently have a small mass) have been proposed, but their mass is too small, and their numbers (although HUGE) are too few, for that mass. So some other "exotic" matter is being sought... and it just so happens that extremely massive "partners" to the presently-known particles are predicted by supersymmetry theories (which themselves are desirable for a number of reasons). These particles include the WIMPs.
So scientists aren't just making this up out of the whole cloth, but instead are doing it for excellent reasons. (Which has nothing to do with whether the University of Rome group has actually found evidence for WIMPs...)
I suspect even if he was personally transported to the center of the sun and personally experienced it (and survived) he would still not believe it. Dont forget about 200 years ago Kant proved we dont exist ;) Socrates? Wrong. Kant begat socialism, communism, cultural subjectivism, the masses who dare not believe in reality and find dark matter no more believable then the chair they sit on.
I know I exist and I know the sun is not made of licorice and anyone who behaves to the contrary is liveing a sad and wasted life.
Dark matter is affected by gravity but apparently nothing else. Perhaps this is the waste product of black holes? Matter goes in, dark matter comes out.
*squeeeze*... PLOP.. ahhhh.. dark matter
nothing escapes a black hole
Just goes to prove that they should hire us nerds to make their webpage so people aren't getting in for free.
Why does this sound to me just like the "ether" that Science gave up on over one hundred years ago?
Matter with negative mass is something else entirely, and is responsible for antigravity.
According to super-symetric theory, the existence of antigravity is unlikely, specifically because gravity would be the result of the exchange of gravitrons (charge 0, spin 2) between particles. It's symetric opposite would be charge 0, spin 2, i.e. a gravitron. Gravitrons would be their own complements, so antigravity doesn't fit too nicely with super-symetry.
However, I have my own litte GUT which so far works pretty well (similar to super-symetry + general relativity, but it still needs a lot of work), and I think anti-gravity is possible, though I'm not sure if we can ever create it.
Could a disturbance in this matter be made in to a sensor of some sort to detect movement or disturbances in magnetic fields? Who knows?
Could this "dark matter" really be the force, and could we detect disturbances in the force?
Yeah. Just read that, baby.
DARK MATTER.
Oh, sure. DARK MATTER. BLACK HOLES. Endless pits where we can throw down "matter" ( = money ).
I love how these bastards are always trying to use racial parallels in everything to scare people. Would "gravitational hole" sound scary? NOOOO!! But BLACK HOLE, man, that sounds SCAAAARY. Better give us our research dollars.
DAAAAARRRRRK MATTER.
Oh, sure. Blame all the problems of the universe on the black man.
I love how lilly white academics are so quick to label everything black as if it's a problem instead of letting us manage our own destiny.
That's the problem with the academic types -- they claim to be open minded, but in reality their minds are just another kind of ghetto. Equal rights for us as long as we don't date their daughters.
I prefer the unmasked scorn of honest bigots to the rat-behind-your-back crap these acadmic liberals come up with.
What's next, rent control for Matter of Color?
so, maybe there's more matter out there than just dark?
...if you use thi s link. It replaces www.nytimes.com with partners.nytimes.com, please do the same when you post stories.
If instead you go to http://www10.nytimes.com/library/national/science/ 021900sci-dark-matter.html, it will bring up the story, with no login and no cookies whatsoever.
Interesting.
Did read the article? Have you ever taken a particle physics course? Do you even understand how science works? I don't mean to flame here, but frankly your quick dismissal of this possible discovery as bovine fecal material seems extremely premature.
As someone who actually has taken a course in QM (not particle physics in particular), I do know that interaction cross-sections depend on a number of factors, and mass is only one of them. And the mass is usually not even the most significant factor for calculating a cross-section. More often then not, a particle's charge (or lack thereof) is much more important than it's mass.
I think some healthy skepticism is warranted here, but an out-right dismissal is totally unfounded, at least until some other groups have had a chance to look over the data and attempt to confirm the experiment.
Shop Smart, Shop S-mart!
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 development "is just the tip of an incredible iceberg, if this is right."
So what can we do with the WIMPs? I hope
A simple experiment:
The elves surely must have some mass. Hmm... I wonder what the possability is that the keys were sucked out of existance by random weakly interacting antimatter collisions :-)
As for the difficulty of detection, wouldn't one of the active neutrino projects, like SNO pick up some very peculiar collisions if dense matter is going to occasionally interact and spew a photon? Off the cuff, wouldn't the intensity of photons released during collision of a neutrino differ greatly from that of an atom with the mass of Nickel, with an unspecified velocity?
Oh wait... it appears that's what they did... using seasonal fluctuations in the earth's velocity. That makes sense. I'll be quiet now.
Some day I'll have to get back into Physics.
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.)
When it comes to pigmeat, it's a question of tomato-based versus vineger-based.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
...One post after another "What physicist can not explain, they invent something nobody can observe" Bullshit - physicists CAN observe it. This experiment is one way to do it. In a few years another sattelite based experiments would be done, that can detect signal from neutralino annihilation directly. It can and will be done.
<^>_<(ô ô)>_<^>
And lo and behold - the superpartner of the photon, called the neutralino
If I remember correctly from my thesis, netralino is a mix of partners of photon, Z-bozon and up and down Higgz (being called Higgzino if Higgz portion dominates)<^>_<(ô ô)>_<^>
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
I understand the issues, I'm just extremely skeptical over whether this is some legitimate, or whether its NYTimes hoopla. Right now, I say its hoopla, simply because I have no reason to believe that billions of mysterious massive particles are flowing through me each second, and we have _yet_ to detect them. This is 99.99% theory at this point and 0.01% fact. The fact is that there's matter out there that we can't see. Blaming it on massive particles that weakly interact with regular mass is as valid as saying little elves are moving things around. Its a hypothesis thats just too absurd in my mind. I'm going to read their paper when its published. I'll make my conclusion then, but right now I just don't buy it. ;)
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
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
Not necessarily. Anti-matter has the same physical properties as regular matter, but the atomic charges are reversed. It still has volume and therefor it can be dense. It is also possible that there may exist anti-dark matter as well.
I think you miss the point. This is pure science and its not something thats very profitable. They do it for the same reason programmers spend late nites with lots of soda and pizza hunched over a couple of megs of code trying to figure out one problem. They want to better themselves and the human race.
n|t.
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
I bet he's american.
Haha, fuck the human race, I only do that for money.
Well, I read through the preprint (linked somewhere above); and the INFN guys attempted
to isolate their NaI and phototubes by sealing
it in a box and flushing with N^2. Later in the 'print, they mention that when they look at the temporal variance in their 'background' (defined as counts above 90 keV), it is consistent with zero.
I'd rather see the paper after the referees have hacked it up, but they seem to understand their apparatus quite well.
- B
What's up with all these wimpy sciantific theorys these days?
[ c h a d o k e r e ]
ReadThe ReflectionEngine, a cyberpunk style n
me? I'm for MACHO, MACHO matter.
On earth it would be about... 9.8 newtons.
Discovering 90% of what is known the universe is unconsequential if you can't feel it or touch it.
Answering a long-standing problem in astrophysics is not inconsequential in my opinion. Unlike you, many, including myself, do have a healthy interest in how the universe works, and when a problem such as this appears as if it may be answered (I'm skeptical, and I'll wait to read their paper and see some supporting evidence before I'm convinced), we understandably take interest.
An experimental/observational validation of supersymmetry would itself be a momentous achievement, even apart from the context of dark matter, as it would have a significant impact on how we understand the physical world at its most fundamental level.
I do hope it's a major break thorugh and produces something useful in every day life.
I'm of the opinion that a measure of our scientific inquiry and discovery should remain separated from the incessant "what good is it?" questions. It's bad enough that most such science can't get funded anymore, that the politics of acquiring research funds requires, typically, a "product" after a year or two [often at the expense of doing a quality job of understanding the science], that only "tried and true," conservative problems seem to get attention, and that much of the business of doing science has become entrenched in rehashing dogma and maintaining the status quo.
Sometimes human beings do things that aren't necessarily useful in everyday life, but yet enrich the human experience somehow. If you've ever posted to Slashdot, played a video game, read a novel, looked at a pretty painting, attended an opera, or cogitated your place in this universe, you might appreciate this point. It's somewhat unfortunate that science has been recognized by the layperson primarily for its commercial, and not its philosophical, value.
My apologies for the long-winded response to your post.
-r
I don't think we are going to be making any major breakthrough in astro physics for a while becuase I think we've gone too far past reality with the theorys. I suspect our current gravity theorys are simply wrong at some fundimental level and thats holding us back. Right now we can predict some relitivity and subatomic detals down the 30th decimal place but I dont see that as proof of correctness. We've got GPS sats that have clocks that just aren't doing what supposed to be doing in orbit. Gravity probe B's gyroscope isn't spinning down at the correct rate and gravitational geoid modles just don't fit proplery. Zero-G experiments bring up more questions than answers.
If we look back to all areas of science, we see a trend:
1) make a theory that fits the general case
2) expand it till it works for all cases
3) throw the thing out once someone see the light
4) have a simply theory that works.
this has happend so many times in the past and the only consistant lession is that we will repeat the trend.
One of my theorys is gravity does push. These are lots of reasons why this can't happen and there are some easy to read accounts of the reasons in Dr Fineman's books but all those reasons are based on a gravity particle concept that we know isn't right. Calculus was invented because Newton was tring to prove the math behind gravity. It turns out that he couldn't integrate gravity pushing but he could do it if he decided gravity pulled and we have been using that theory since. So how does one prove if gravity pushes or pulls?
...these WIMPs, they run gnulix, yes?
...signed, the ever-lovable gnulix guy!
"If this is right, this is clearly one of the great discoveries of the last hundred years," said Dr. Michael Turner, a cosmologist at the University of Chicago. "To discover that most of the matter in the universe is not what we're made of -- that's pretty spectacular."
The implications of this discovery, if proven correct, might extend farther than appears at first glance. When discoveries like this are made things that seemed absurd yesterday suddenly become plausible.
Particles 50 times heavier than a proton which almost always pass through other matter without a trace - not only can we not observe these particles with our eyes, but we up until now haven't been able to observe them with our best scientific instruments. What if these particles don't just occur randomly? What if they have structure, either naturally occuring and evolved, or by deliberate design?
It would be interesting indeed if we were to discover large scale objects such a rocks, planets, or even life forms made of this stuff.
I'm not a journalist, but I play one on slashdot
Yes, but how dense is this stuff?
> All you touch and all you see Gratuitous Pink Floyd reference?
Wah!
yep,
I've read it... it plotted the next several Billion years of mankinds exsistance, I think it was called "Ring" because of the 'other' advanced baryonic race that developed the great ring as a means of slowing the advance of the dark matter birds.
MRo
here it is: http://www.amazon.com/exec/obidos/ASIN/0061056944/ qid=951036188/sr=1-2/002-9032926-8185040
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
Login: slashdot64
password: dotslash
Only dead fish swim with the stream...
When I go out to dinner tonight I'm gonna go out to a Mexican restaurant and order some of those Neutralinos. They sound tasty.
Woah.. Imagine what SEX will be like when they tame the wimps..
"Consider how lucky you are that life has been good to you so far. Alternatively, if life hasn't been good to you so far
Firstly, from calculations of a galaxy's structure. Even using simple methods like the Virial Theorem (2T=V where T is kinetic energy and V is gravitational potential energy IIRC) it can be shown that given the mass of stars in a galaxy, the diameter of the galaxy and the speed of rotation the gravitational potential of the galaxy is only about 10% of the value required to prevent the stars being flung out by centrifugal force. Seeing as galaxies are stable physicists must assume that the other 90% of this mass is "dark matter" which we cannot detect using current means. More detailed calculations show this is most likely to exist as a huge disc in which the visible galaxy is embedded.
The other reason has to do with the cosmological constant from Einstein's General Relativity. This value determines the "flatness" of empty space-time, and experimentally this as been measured as being less than 10^-120 i.e. almost certainly zero. However if the Universe is flat then the density of matter must be equal to some critical value. Current calculations of the matter density of the Universe vary from between 1% and 10% of this critcal value, and so again physicists have to assume the presence of dark matter which the cannot observe to account for this discrepancy. Given this critical density the Universe will eventually expand at a constant rate and there will be no Big Crunch.
Of course, the other explanation is that all these theories could be totally wrong, but this would require changing a lot of the physical theories of this century so it isn't too likely IMHO.
A truly excellent series of books, which are in order:
They are very much worth reading and have probably one of the grandest scopes of any hard science fiction I've ever read, and some amazing ideas about the history of the Universe and physics.
It's nitpicking, but it's important to realize this. Because someday somebody's going to find out what the REAL contents of the universe are. and maybe modern theory will be just a little bit off, but close. Or maybe we'll find out that the vast majority of the universe is made out of licorice flavored jelly beans.
As silly as that sounds, the "dark matter" theory and the "licorice" theory stand on equal ground scientifically until the actual proof of the matter comes in.
Certainly, you and I personally have no direct evidence that the center of the sun is not made of jelly beans. However, we also have no direct evidence that we are not the proverbial brains in vats. I suppose you can set your standard of evidence so high that "the center of the sun in not made of jelly beans" remains an unproven theory. Even if you do so, it is rediculous to suggest that the jelly bean theory and the dark matter theory are on equal ground, just because both are unproven. The difference is that the dark matter theory has a body of evidence supporting, while the jelly bean theory does not. While the evidence for dark matter may not meet the standard of proof, that does not relegate it to the same level as all unproven theories.
Given how farfetched physicists are willing to go these days to explain what they can't observe (dark matter), why don't they propose the existance of God to explain the dark matter.
1. Assume that god is omnipotent and everywhere simultaneously
2. Assume that omnipotence correlates with energy
3. E=mc^2
4. God has direct interaction with 1/1^7 individuls per year.
5. God is an individual (can be considered as a quanta)
6. God does not emit electromagnetic radiation
Therefore god is WIMP-Weakly Interacting Massive Particle.
no sig.
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.
For anyone that doesn't want to get themselves a login at New York Times you can use user:slashdot_wimp passwd:slashdot
You should write him about the banner idea, tho. ;)
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
So much information and so little knowledge.
Viel laerm um nichts.
At least it keeps these people off the streets.
if i remember correctly, it had "birds" made of dark matter and they were trying to put out the sun by flying into the core, then carrying matter to the outer rim... which had the effect of reducing the sun's temp... it seems that light matter (??) effected them in some unpleasant manner and they wished to put an end to it...
no .sig please
If this is anything like a black hole, extremely dense. So much so that by earths gravitational standards, a single teaspoon of it would weigh several thousand tons. Now I've also heard theories that dark matter is the same as anti-matter (not sure of the validity), in which case it would be undense :)
If dark matter is supposed to weigh so much, how can something the weight of a nickel atom be dark matter? and also, when the paper is published, someone please link to it on /.
-- Napalm sticks to kids.
according to my books/astronomy professor it is calculated that dark matter makes up AT LEAST 90% of the matter in the universe (by using rotational velocities of galaxies one can determine how much matter must be contained). WIMPs could be only a small part of dark matter, or they could be the whole sha-bang, tons of research here... About the only they they are sure dark matter is NOT is waffles, too bad too, i'm hungry :(
I've never understood why it is so important to cosmologists to find dark matter. Why does there need to be enough matter to cause a Big Crunch, anyway? Can anyone help me?
-raph
Who else is pissed at the US government for axing the SSC? So much could have been learned, but they have to give their money to Defense so that they can develop toys like the Aurora so we can die faster. Sheesh.
-raph
Of course you're right, I should have said "opposite charge", not "negative charge". Otherwise, electrons would be antimatter! However, I don't see how you could have neutral-charged antimatter. Negative zero is still zero, after all. Is it possible to have an antiphoton?
---
Oper on the Nightstar
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.
WIMPs
:)
Weakly Interacting Massive Particles
I love how they come up with these acronyms.
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 most obvious problem I see is that "all the matter you touch and see" isn't 20% of the universe.
.00000000000000001% of the universe would be more like it.
The problem is that not only is dark matter theoretical - most non-dark (enlightened?) matter is also theoretical. Pluto, the center of the sun, heck even the center of the earth - all these are recognized only in theory.
It's nitpicking, but it's important to realize this. Because someday somebody's going to find out what the REAL contents of the universe are. and maybe modern theory will be just a little bit off, but close. Or maybe we'll find out that the vast majority of the universe is made out of licorice flavored jelly beans.As silly as that sounds, the "dark matter" theory and the "licorice" theory stand on equal ground scientifically until the actual proof of the matter comes in.
Judge Pag, the Learned, Impartial, and Very Relaxed
This would certainly explain all the stale bread in Italy. Italy, a narrow strip of land between two bodies of water would "focus" the neutralinos (how did they discover they are male?) and cause the bread to age faster than in France, where stale bread is used to feed the pigeons. Please note that in Venice even the pigeons will NOT eat bread; they prefer a diet of corn and sunflower seeds.
It is not clear if the people in Italy would age faster also. But there, especially in Rome, more people wear black, perhaps to protect themselves instinctively from the WIMP swarms. Obviously more research is needed now the meutralino break-through has been made.
Would Vitamin E be effective against the focused neutralinos? If only Linus Pauling were still alive to conduct this research...
Wovon man nicht sprechen kann, darueber muss man schweigen. Ludwig Wittgenstein
I should really read up on this, but I've always been curious as to how they know exactly how much dark matter they think exists. I mean, it it light bending, gravitational interaction or what?
Is it possible that this matter is maybe some form of elementary particle that doesn't give off other particles (ie, the smallest particle which would not give off photons) and that's why we can't see it? Just my own questions on the subject. Wish I knew more about it.
Null_Void
The Michelson-Morley Experiment disproved the existence of the ether(substance that light waves could travel on) because the theoretical ether didn't show any(negligibly small) affect on a speeding light wave. This dark matter doesn't show any affects towards common matter, does it react similarly towards light? And, could this dark matter act like the ether and provide a medium which light waves travel through? --just a few thoughts aloud --digital clock: 44:44 3:33 :22 :1
The San Fransisco Chronicle has an article, the paper itself is located at www.lngs.infn.it.
ONLY IF BY 20% YOU MEAN 0%
the status quo you comment on are the very reason that you are able to use computers. Quantum mechanics is responsible for our current technology so they must be doing something right. And you probably aren't.
>Bzzt. Wrong. Antimatter has negative charge, not negative mass. Matter with negative mass is something else entirely, and is responsible for antigravity.
Bzzt. Wrong. Antimatter has opposite charge of its corresponding normal particle. This may be positive, neutral or negative.
>>How much would a pound of it weigh?
>A pound. Duh.
A kilogram of it, on the other hand, may weigh many, many, many newtons.
If I remember right, the theory about dark matter involving WIMPs would also need neutrinos somewhere in the equation to comply with rotation curve evidence (i dont remember exactly what that evidence was.. anyone?)
Also, I read that the WIMP/neutrino idea would challenge a few things supposedly known about BBN (big bang nucleosynthesis). Again my memory fails me.. Does anyone know where the two ideas clashed?
~moRlly
www.thecounterculture.com/~morlly
"I don't want the world, I just want your half"