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Most Sensitive Detector Yet Fails To Find Any Signs of Dark Matter
ananyo writes "A U.S. team that claims to have built the world's most sensitive dark matter detector has completed its first data run without seeing any sign of the stuff. In a webcast presentation today at the Sanford Underground Laboratory in Lead, South Dakota, physicists working on the Large Underground Xenon (LUX) experiment said they had seen nothing statistically compelling in 110 days of data-taking. 'We find absolutely no events consistent with any kind of dark matter,' says LUX co-spokesman Rick Gaitskell, a physicist at Brown University in Providence, Rhode Island. Physicists know from astronomical observations that 85% of the Universe's matter is dark, making itself known only through its gravitational pull on conventional matter. Some think it may also engage in weak but detectable collisions with ordinary matter, and several direct detection experiments have reported tantalizing hints of these candidate dark matter particles, known as WIMPs (Weakly Interacting Massive Particles). Gaitskell says that it is now overwhelmingly likely that earlier sightings were statistical fluctuations. Despite the no-shows at XENON-100 and LUX, Laura Baudis, a physicist on XENON-100 at the University of Zurich in Switzerland, says physicists are not ready to give up on the idea of detecting WIMPs. They may simply have a lower mass, or may be more weakly interacting than originally hoped. 'We have some way to go,' she says."
Pulling in other posts below it :D
"When information is power, privacy is freedom" - Jah-Wren Ryel
Just sayin'...
The problem is that they've got the wrong people trying to accomplish this. If they really want to find something they should just tell the NSA that "there exists the theoretical possibility that some type of unknown phenomenon is present that cannot be excluded from terrorist activities" and the NSA will not only find the dark matter, they'll find something on it so embarrassing that it will announce itself to the rest of the world.
they won't need a very sensitive detector for that dark matter
Maybe it's just not there.
Dark matter always reminds of the 18th century hypothesis of the aether.
http://en.m.wikipedia.org/wiki/Luminiferous_aether
Same principle. Same made up matter that no one can see or detect but somehow fills the entire universe.
from the article :
"... physicists are not ready to give up on the idea of detecting WIMPs. They may simply have a lower mass, or may be more weakly interacting than originally hoped....We have some way to go"
So former wimps are having a hard time finding WIMPs themselves? That's an interesting turn of events !!
What is best in life? To crush your enemies, to see them driven before you and to hear the lamentations of their women.
...that maybe they're not seeing it because it's just not there?
Just a suggestion.
So undetected dark matter pulling stuff together more than expected and undetected dark energy pulling stuff apart more than expected.
Hmmm. Isn't it possible that the theory is just wrong about how gravity and spacetime works at really large scales?
Where are we going and why are we in a handbasket?
Usually it is in and around the drumstick area.
Finally some place where God may be hiding! We don't know what is attracting those particles, so clearly it is God! (Which god is an entirely other question.)
Dark matter experiments sometimes remind me of the luminiferous aether theory experiments of the 19th century. After a certain number of tests fail to return a result you start to suspect that the experiment is working perfectly it's just that there's nothing to detect and something is fundamentally flawed with your theory.
clearly it's too dark to see so they should just use a flashlight.
Anons need not reply. Questions end with a question mark.
The SANTA and EASTER BUNNY teams are also reporting negative results today. Film at 11.
Circle the wagons and fire inward. Entropy increases without bounds.
from astronomical observations that 85% of the Universe's matter is dark"
They don't *know*, they're deducing this from reconciling observed data with general relativity but it's far from certain.
However relativity is not infallible, maybe it's true only in a special case -- like how Newtonian mechanics works great but only in a special case (bigger size than quantum scale, less velocity than ~1/10 c, etc)
Maybe at very large size and mass such as galaxies, general relativity doesn't hold and there's a better theory for explaining motion and gravity. If so we wouldn't have to invent nonexistent dark matter to account for the faster-than-expected galactic rotation and other things.
the fuck with the big-ass ad on the front page?!?!?
Several different experiments have tried to measure dark matter directly in the lab, and the experimental situation is pretty confusing. This plot shows the confidence intervals and exclusion limits for various experiments (but it does not include LUX yet). The shaded regions are confidence intervals, that basically say "we've seen dark matter, and its properties lie somewhere in this region. But the dotted lines say "we haven't seen it, and if it exists, it can't lie above these lines".
What is strange, then, is that all of the detections are in regions that have been excluded by other experiements. LUX just makes the situation even more strained by pulling those upper bounds even lower. Still, those bounds and intervals depend on assumptions about the properties of dark matter, and it may be possible to reconcile the results.
It will be interesting to see what happens to those tentative detections when they get more data. My bet is that in the end some systematic effect will be found to be responsible for the apparent signal. Or (much less likely) that they were just flukes. But who knows?
Both Dark Matter and Dark energy are expressions of unknown variables that are required to make the Standard Model work. They do not represent actual things, but rather numbers on one side of a balanced formulae. While ther could be unobservable matter and energy, it is likely that most of these unknown variables result in our partial understanding of the matter that we do see.
unless you are using DOS
if this is supposed to be a new economy, how come they still want my old fashioned money?
I had a girlfriend who was hyper sensitive.she would be able to detect it.
When generally relativity is properly applied to the problem, dark matter will been seen as a mathematical illusion created by previously inadequate approximations.
Matter of fact, it's all dark.
The dark matter theory has always felt a bit contrived to me. But I don't have the background to make an cogent argument against it, nor have standing for my words to carry weight.
Gravitational lensing.
(And I'm kidding here:) You can't explain that!
If dark matter happens to consist of four or more physical dimensions we would only be able to "see" what is the equivalent of a circle of a rod, or the roots of a tree. We cannot "see" more than 3 physical dimensions but could measure the gravitational effect of the 4th, etc. We are essentially Plato's "man in a cave", http://en.wikipedia.org/wiki/Allegory_of_the_Cave, when it comes to dark matter.
Dis they remember to plug it in ?
My vast experience tells me that that is usually what is wrong
Of course they hadn't considered it earlier! What fools they've been shown to be!
(Hint: If you're a random commenter on Slashdot, then, yeah, the experts in the field have probably considered your idea before you suggested it.)
HAND.
At some point in the 20th Century, theoretical physics moved from science (where maths was simply the tool used to create MODELS, models that no-one ever thought were real, but offered a predictive mechanism) to maths, where idiots claims mathematical models are the SAME as reality. Beta class 'scientists' found this nonsense very easily to swallow. Better again was the fact that spewing unsubstantiated mathematical nonsense was a LOT easier than doing real scientific research.
Turn theoretical physics into a branch of maths, and writing speculative papers in what is CLAIMED to be theoretic physics becomes infinitely easier. In maths, nothing is SEMANTICALLY wrong, so long as the maths presented is SYNTACTICALLY correct. This is because, obviously, maths is ABSTRACT. By pretended theoretical physics is equally abstract (rather than describing reality), one can puke up endless nonsense in published papers, justified PURELY on the basis of 'correct' maths.
'Dark Matter' is a great example of this. Current models of the Universe hit a massive snag, when it became undeniable that the Universe is expanding, at an accelerating rate. That disgrace to physics, in his tedious coffee-table book, told the world that either the Universe was expanding forever, but forever slowing down, or that the Universe would eventually start to shrink back on itself. The one possibility that only a year or so later was proven to be TRUE was the one possibility the hilariously hopeless Hawking stated could never be true.
But Hawking is a mathematician PRETENDING to be a physicist, so it matters not to him (or his supporters) how hopeless his models prove to be, so long as the models themselves have an abstract mathematical 'correctness'. We see the same with 'climate science' where the worse the predictions of the models offered by Obama's approved scientists prove to be, the more the sheeple are told to trust these people. This isn't science- this is propaganda, social engineering (and in the case of much cosmology) and religion dressed in the clothes of 'science'.
'Dark Matter' is the name given to a block of maths that attempts to patch up certain current models of the Universe that otherwise fail in major, and testable predictions. It is as if the police arrest a 5 foot black man for a crime they KNOW was committed by a six foot white man, but invent an 'adjustment' called 'dark matter' to justify the 'correctness' of their arrest. It is nothing but an "after the event" fudge factor that has no place in science.
But such utter garbage provides well-paying and well praised careers for tens of thousands of theoretical physicists across the planet. And because no APPLIED physics is expected to result from their blue-sky flights of fancy, no-one cares. It would have been great if Hawking had resigned his chair AFTER the humiliation of the discovery that the Universe is expanding at an accelerating rate, but like all the worst and most aggressive idiots on Internet forums on ANY subject, after having been proven wrong he simply stated "I was RIGHT because I was wrong".
it's spiders.
teeny-weeny black spiders.
hundreds of Quattuordecillions of teeny-weeny black spiders per cubic centimeter, crawling between the very fabric of creation.
crawling in your ear, in your eye.
SPIDERS.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
This has been bugging me for years, but I don't understand enough to either substantiate or falsify my thoughts. I also don't want to try and convince people that it's right since it sounds crazy even to me, but please tell me if you can find something wrong with it... I know that there are some extensive theories and observations involved, and I'm very aware of the relevant xkcd... http://xkcd.com/675/
All that said, it's very interesting to consider the possibility that there's a common cause of the observations that prompted dark matter/energy theories. I've read far too much about physics on Wikipedia trying to disprove the notion, with little success. All I've managed to do is find more and more curious aspects of things that would be *solved* by the idea.
I'd be very interested in someone finding evidence to falsify the possibility of dark matter and energy sharing a common anti-gravitational cause. I've been trying to find a contradiction for a very long time, and have found nothing conclusive.
If we consider that the anti-gravity could be caused by the missing antimatter purportedly absent due to baryogenesis, we might expect to find annihilation emissions in the spectra (Hmmm... http://en.wikipedia.org/wiki/Space_roar ? Doubtful, but who knows?). However, such an observation could be absent for at least two possible reasons: It doesn't exist...or the bulk of the antimatter is something weakly interacting and low-mass, sharing the same problem as the standard dark matter model.
I don't mean that antimatter would fall up in such a changed model. Its inertial mass could behave as expected, and follow spacetime the same way as normal matter. It would just exert repulsive influence. Galaxies would be compressed by rings (or spheres, how dark matter is modeled?) of antimatter surrounding them and spread out somewhat in intergalactic space (dark matter), while being repelled from each other by the spherical gravitational dipole effect (dark energy).
If you model a binary system with one matter and one antimatter particle, they orbit a barycenter on the opposite side of the matter particle from the antimatter particle...in lock-step with each other. Put a black hole at that barycenter, add more particles of each type, and you get an orbiting system that goes much faster than it should from just the matter...just like dark matter's effects on galaxies.
There's some amazing symmetry if you think about this, and some weird implications. Inertial and gravitational mass would no longer be identical. Relativistic mass might be gravitationally neutral. An antimatter particle would chase a matter particle and require new interpretations of conservation of energy (Probably one of the biggest potential arguments against the whole concept, except it violates assumptions, not any evidence I'm aware of).
My most recent consideration from all this was the idea of applying CPT symmetry to the big bang (since it could be expected to involve both matter and antimatter), with some truly crazy implications. Unfortunately my understanding of it seems to be even more lacking than I thought, and I'm not sure how to mathematically formulate/test the possibility of the Universe sharing a common beginning and ending if you look at matter and antimatter versions in opposite time-space terms.
I don't know what I'm doing, and really wish someone could put this musing to rest one way or another. Unfortunately, I doubt we really have the experimental evidence either way. All of my musings amount to relaxation of assumptions--I haven't found a concrete contradiction, and all the predicted effects seem too subtle for current experiments to show.
If anyone could give good evidence for falsification of this common cause hypothesis, or point me in a direction for finding it, I'd be very appreciative. I've spent far too much time thinking about this with nothing to show for it, despite trying to break it.
Thanks for reading. Please get this out of my head. :P
True story.. good luck finding it with your current methods.
I still think it is lots of baryonic matter in black holes or whatever, aka MACHOs(Massive Compact Halo Object).
Anytime I lose something in the dark I just get a bigger flashlight. All we need to do is launch a giant version of those 30 LED flashlights you can get at Harbor Freight for like $2. It has to be in pink though just to make it pretty.
Harrison's Postulate - "For every action there is an equal and opposite criticism"
The main lines of evidence for dark matter:
* Galactic rotation curves
* Velocity distribution in clusters of galaxies
* Gravitational lensing in general
* The Bullet Cluster in particular
* The pattern of positions of galaxies in the universe
* The pattern of Baryon-acoustic oscillations in the cosmic microwave background and in the galaxy distribution
* The primordial distribution of light elements in the universe
We know of some kinds of dark matter already: There is a huge amount of neutrinos left over from the big bang, and since these interact very weakly with other stuff, they definitely qualify as dark. Other known kinds of dark matter are black holes, and compact, cold objects made out of baryons (normal matter). So dark matter exists.
The problem is that there isn't enough of the normal kinds of dark matter. To match the pattern in the cosmic microwave background and the amount of hydrogen, helium and lithium in the universe, one needs by far most of the dark matter to be non-baryonic (i.e. not normal matter, but something like neutrinos, but heavier). This kind of dark matter is something we have to postulate exists in order to match observations. But when we do assume it exists, the theory matches observations extremely well. As an example, look at the CMB power spectrum as mesured by Planck. The error bars are so small that you mostly can't see them, and the points lie smack on top of the theory curve. But only if dark matter is included.
And it just so happens that the amount of dark matter that makes theory match the points in that graph also makes the element abundances, galaxy distribution, lensing observations and galaxy cluster velocities work too. Such a coincidence is pretty telling, I think.
But yes, people have tried to avoid dark matter by modifying gravity instead (though nowadays, the most common motivation for modifying graivty is to avoid dark energy). MOND is an example of that. MOND is like normal Newtonian gravity as long as the gravitational acceleration is large (like in the solar system), but instead of falling to arbitrarily low values as distances increase, the gravitational acceleration has an effective minimal value that it approaches as you move away. And such a constant value is just what you need to get the flat rotation curves we observe in galaxies. Which is the problem MOND was invented to solve.
MOND is an elegant solution for galaxies, but it loses all its elegance and predictive power when you try to apply it to the other areas where dark matter shows up. And in some cases it is plainly ruled out as an explanation. MOND, like Newtonian gravity, is a central force, which means that the force points towards the mass that generated it. But in the Bullet cluster, the gravitational force points towards areas with little visible matter, away from areas with much visible matter. This is impossible to fit into MOND. So the Bullet cluster basically killed MOND.
Some of MOND lives on in TeVES, which is an attempt at a relativistic version of MOND. Sadly TeVES has none of the simplicity and elegance of MOND, and while it can explai
If these clowns had bothered to watch Star Trek they'd have know that you can detect dark matter by bombarding them with metreon particles.
Two of my imaginary friends reproduced once
Did they leave the lens cap on?
It's not going to do you any good looking for the Dark Matter here.
I'm keeping it safe and sound on the Dark Side of the Moon.
Oh, and next time use a flashlight.
-- Tigger warning: This post may contain tiggers! --
"Most Sensitive Detector Yet Fails To Find Any Signs of BLARGH. Even though no signs of BLARGH have been detected, it doesn't mean that BLARGH does not exist!"
... well done, Sir!
While the scientific process as it is right now WORKS, it's not very efficient. There is WAAAAY too much dogma and overconfidence in science right now, and that slows down progress trendously while people repeat similar experiments over and over again waiting for their scientific biases to be confirmed. Science has, to some extent, gone insane. The solution is to make science more open, democratize it, and let the masses attempt to solve the problem. Let's not forget, Einstein was a patent clerk, and I suspect that his access to knowledge was one of the MAJOR reasons he was able to contribute so much to science. I suspect the resistance to democratizing science comes from intellectuals who like to be at the top of the food chain. In other words, as almost all other problem in our world, it comes from greed. A it's an incorrectly assumed Darwinian attitude, derived from the logic that "evolution" applies to human interaction. (Don't get me wrong, I totally agree with the theory of evolution. I am not a crazy creationist nut. I am using the word "Darwinian" in the same context that Dawkins uses it, to oppose it in the context of human interaction.) And, unless and until we irradicate this Darwinian attitude, science and EVERYTHING ELSE will stagnate. We will be lucky if we make it to the 22nd century. Only a miracle technology can save us at this point.
As usual Feynman made the acute observation that theories that predict effects just beyond what is seen are highly suspect, especially when they move the goalposts.
Or dark energy. Or black holes. Or machos. Or wimps. or whatever other mathematical fantasy they dream up to patch the ever widening gap between observations and an outdated theory.
Because we live in an electric universe. Because the electric force is orders of magnitude stronger than gravity.
"The Electric Sky" explains many many things that surprise those still worshiping the standard model as if it were gospel.
http://amzn.com/0977285111
There is no dark matter. Changing our view of the nature of space can however explain what we observe. Einstein tried to show the way when he described gravity as the deformation of space.
We incorrectly deduce that there must be unseen mass because the outer edges of galaxies move at a rate that implies missing mass. We use the doppler shift of light to measure the speed of the stars in the galaxy. We assume that the speed of light and the speed of gravity are the same as they pass through the usual three dimensions of space. In a theoretical vacuum this may be true, but we live in a universe filled with matter and charged particles.
By changing our assumption and considering space as two three dimensional fields, electrostatic and gravitational that are superimposed upon each other we can easily reconcile what we see. The galactic center has a stronger gravitational field than the outer edge of the galaxy and gravitational space is compressed relative to electrostatic space. When we use light as a yardstick we fail take into consideration that the galactic gravitational field is compressed where the galactic electrostatic field is not.
This the Electro-Gravitic theory of space and provides a clear explanation for dark matter, dark energy, refraction and the unification of the strong force and gravity without resorting to anything we have not already proven experimentally or incredibly complex math that defies human understanding.
Greed is the root of all evil.
Does temperature affect gravity? What about light, does heat or cold affect the speed or strength of light beams? /Stolzy
it's widely accepted that it's probably made up. Google or youtube '3d time'. Much better theory imo.
The book has its moments, but the kludges presented on pages 72 to 74 are a mess. In short, Woit doesn't have answers, just valid criticisms of string theory.
https://www.youtube.com/watch?v=fXJxtp8inWg
I think there is an ether. It is not "particles", hence the difficulty measuring it, but energy -- thus explaining the 10^^120 discrepancy in the measured vs. calculated background temperature.
- Floyd Maxwell, author of "Spring-And-Loop Theory"
I come here for the love
Sean Carroll's "Dark Matter, Dark Energy" Great Course to the rescue. Like all GC's, it is very expensive, but libraries seem to have it.
I come here for the love
It's awfully hard to detect a math error with a physical sensor.
Yep!
And at the 2012 Electric Universe Conference in Las Vegas, I got to see a lecture by a renowned astrophysicist / astronomer who found a cluster of stars supposedly orbiting around a black hole at a phenomenal speed. In fact, when astronomers calculated the speed one of the stars was whipping around the supposed black hole, it came out to a staggering 2.5x the speed of light. It's photographic evidence over the course of many weeks that is very hard to debunk.
Now, if an entire star system can be flung into FTL speeds, i think that paints a pretty rosy picture for far less massive spacecraft, you know?
Slashdot Valentines Beta Massacre: iT WORKED! The boycotts killed Beta!!
No SETI.
Now no DARKI.
Pity.
Pity Pity.
Sniffi Sniffi. :(
On occation, I've made a note to disable central air, close windows, keep out sunlight, and ignore high temperature fluxuating days, and would almost always catch *something*.
I've come to a few theories as to why these things move. Static, The moon, ELF waves, and possibly dark matter.
The key to catching these things is to use an older , non compressing, non high defitioning camera, and use a very low threshold (few pixel changes causes capture ) on the capture software.
Either:
A. There is a fundamental aspect of space/time we don't understand. (Maybe there is some type of Aether?)
B. We don't understand gravity over long distances. (Maybe it has a different effect over longer distances than we are aware)
C. We are not measuring something else properly. Light, time, distance....?
This whole "dark matter" thing has been unreasonably preposterous from the word go.
I hold very few opinions. I hold information based on observation and fact. If you wish to disagree, please use facts.
Neither electric fields, magnetic fields nor gravity fields consist of particles. So perhaps we ought to call it dark energy. It might form a "gravity-dark energy" pair analogous to electro-magnetism.
Much as magnetic fields interact with electric fields, perhaps dark energy interacts with gravity, giving us indications of it, but not being measurable using particle detectors (as the one described in the article).
Thoughts, anyone?
For 30 years the evidence that the SM is incomplete has been building. This result, which frankly I didn't expect, seems like the final nail in the coffin.
The sad thing, of course, is that we have no model for anything else. Nor have we figured out any tests that might find new physics. We've spent the last 30 years building machines to tell us what we already knew.
The happy part of the story is that it's the low-cost machines like this, and telescopes, that keep putting out the real physics.
I frequently find myself stumbling around all the dark matter when I come home late and don't want to wake anybody up. I consider failing to detect any of that dark matter with my most sensitive detector a blessing. My toe is a little sensitive but it could be a lot worse.
i think we have a wrong way of looking at decaying (fission) and anti-decaying (fusion) ...
atoms. these two phenomenon have been dragged into the causal lego realm (for a lack of better wording).
we normally understand it as cutting a piece of cheese into two parts, or pouring two canisters of
water together into one.
it is NOT like that. causality has extra attributes when we look at a "decaying domino" that interacts
with another domino. a hint should be the hard-to-detect-near-non-existent "neutrino".
of course, if certain "violations" were real, the first thing invented would be a framework of the mind
to disallow thoughts that would allow the violations : ) we want the world to make sense!
second we'd need a entity to police this "magic" of willing stuff into existence
Wouldn't it be simpler to revise the laws of gravity at astronomical distances rather then dream up some ridiculous, invisible massive particle?
I really hope someone on here can explain what I'm missing here...
Why is it not possible that "dark matter" is not simply just regular matter like asteroids, comets, planets, nebulae, and neutrinos?
I mean, they're discovering exoplanets at an alarming rate lately and we're still discovering asteroids and comets in our own solar system. Extrapolating these findings to all the other stars out there has got to add up to something substantial, right?
What about stars that have exploded and spewed their contents across the universe? Would not these contents become dark after they cool, thereby making them invisible to us? That would be the entire mass of a star that we couldn't see, right? And there's got to be billions upon billions of these, depending on how far away into the past we're looking, right?
Then there are neutrinos, which we know exist because we can detect them, but do we really know how many of them are out there?
Surely, the mass of all of these normal types of matter would add up to something substantial... right?
Gravity is not proper acceleration. Light can't escape a blackhole because the acceleration of gravity is greater than the speed of light. Information can't move through space faster than light, but there is nothing saying space itself can't move through other space faster than light. We already see entire galaxies moving away from us 3x the speed of light because of space expansion.
Space has mass.
Dark matter is just low energy space.
Dark energy is just space expanding as more energy passes through it.