DARK ARTS: Astronomers using the W. M. Keck Observatory, the Hubble Space Telescope, and other telescopes on Mauna Kea have studied a giant filament of dark matter in 3D for the first time. Image released Oct. 17. 2012.
Image: Image by ESA; additional elements by K. Teramura, Univ. Hawaii Institute for Astronomy
The hiding spots for the particles making up dark matter are narrowing, and the answer to this cosmic mystery could come within the next three or four years, scientists say.
Dark matter is an elusive substance that is invisible and almost never detected, except by its gravitational pull. Yet astronomers say it likely makes up a quarter of the entire universe and dwarfs the amount of normal matter (galaxies, stars and planets) out there in space.
Just last week, particle physics discovery from the Large Hadron Collider in Switzerland cast doubt on a theory called supersymmetry, which predicts the existence of particles that are among the leading candidates for dark matter. That finding limited the types of supersymmetric particles that can exist, but didn't take the supersymmetry explanation off the table completely.
And supersymmetric particles are just one of a number of theorized particles that might account for dark matter. Searches for these and other undiscovered particles have been underway for decades, though none have been detected so far. [Twisted Physics: 7 Mind-Blowing Findings]
"I think we're looking in enough different ways that unless it's something that we just haven't thought of at all yet, it seems to me we're very likely to find it within the next decade," said Dan Bauer, a physicist at the Fermi National Accelerator Laboratory in Illinois working on one of the experiments, called CDMS.
Dark matter on the run
The leading experiments aimed at detecting dark matter are just starting to operate at sensitivity levels thought to be sufficient to detect signals from these particles, and their results should be in within about three or four years, Bauer said.
"If we don’t find it in this next round of experiments, I think everyone will be a bit discouraged," Bauer told SPACE.com.
To be dark matter, the potential particles must all be neutral and stable, and interact very rarely with other types of matter.
Most of these fall into a category of heavy particles called weakly interacting massive particles (WIMPs). WIMPs are predicted by supersymmetry, posits the existence of heavier partner particles for all the known particles in the universe with the same electric charge but different spin. [NASA's Quest for Dark Matter (Video)]
Several experiments are underway to search for WIMPs by placing large masses of material, such as xenon or germanium, deep underground and shielded by many layers of protection aiming to keep all other particles out. If any particles do make it past these barriers and collide with the atoms in the xenon or germanium, they will very likely be WIMPs, the thinking goes.
CDMS (which stands for the Cryogenic Dark Matter Search), started in a tunnel underneath Stanford University in California, and a newer, more sensitive version of the project is now underway even deeper underground in Minnesota's Soudan Mine.
Another WIMP-hunting experiment is called XENON100, the latest iteration of a search based at the Gran Sasso underground laboratory in Italy. And a new project called LUX (the Large Underground Xenon experiment) under construction at the Homestake mine in South Dakota could be a big player, too.
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23 Comments
Add CommentYes, it seems that no matter what possibilities might be eliminated, we can come up with still more ideas for what dark matter might be...
Reply | Report Abuse | Link to thisThe required presence of dark matter has only been inferred from our own gravitational evaluations of very large scale, compound objects composed of billions of discrete objects of mass. Perhaps the methods employed in those evaluations, derived from methods of approximation proven for much smaller aggregations of massive objects, do not adequately represent the distributions and interactions of so many discrete objects, such as spiral galaxies.
Please see "Inappropriate Application of Kepler's Empirical Laws of Planetary Motion to Spiral Galaxies Created the Perceived Galaxy Rotation Problem - Thereby Establishing a Galactic Presence for the Elusive, Inferred Dark Matter",
http://fqxi.org/data/essay-contest-files/Dwyer_FQXi_2012__Questionin_1.pdf
J. D. Carrick and F. I. Cooperstock. "General relativistic dynamics applied to the rotation curves of galaxies." Astrophysics and Space Science. 337 1 (2012): 321-329.
http://dx.doi.org/10.1007/s10509-011-0854-z
James Q. Feng and C. F. Gallo. "Modeling the Newtonian dynamics for rotation curve analysis of thin-disk galaxies." Res. Astron. Astrophys. 11 (December 2011): 1429.
http://dx.doi.org/10.1088/1674-4527/11/12/005
http://arxiv.org/abs/1104.3236v4
Here's a thought. Since we 'see' things due to photons interacting with our visual sense, could there be anti-photons which do not interact? After all, there is antimatter...
Reply | Report Abuse | Link to thisrick, there is no difference between a photon and an anti-photon. Particle-Antiparticle annilation creates photons.
Reply | Report Abuse | Link to thisI've been watching this line of research for a long time and will continue to do so with great interest. Science has contributed greatly to potential solutions and cures for problems that have beset mankind, and will ultimately provide understanding that may lead to real cures for disease and even hunger on a large scale. All will depend upon us to do the right thing with that knowledge. Complacency and ignorance will certainly not provide cures for cancer, Alzheimer's, hunger, or give mankind the impetus to take the path of peace versus war.
Reply | Report Abuse | Link to thisSo, yes, mind! Let the research continue, as it will certainly lead to new discoveries that can be translated into better understanding of our universe at a core level; and, from that, the new technologies that may include cures, and clean transportation and distribution systems that will alleviate suffering and even hunger!! Bravo, Dan Bauer, and all of you research scientists, in whatever field of science you strive. Keep up the good work; no matter what, and thank you!
In the one substance, energy, motion can only be in closed circuitry. Globes turn upon themselves. They are "particles". Global shells turn upon themselves. They are "particles". But, all the other differentiations: rings, disks, mobius strips, etc., are what populate "dark matter". The entity we call "I" is such a closed circuit, thus, we are also "dark matter".
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Reply | Report Abuse | Link to thisTrack Record of the WIMPs
Number of years doggedly spent on the “WIMP” hunt = 40
Number of “WIMP” theory papers = more than 10,000
Cost of “WIMP” searches = multiple billions of US dollars
Number of “WIMPs” found = 0, as in ZERO, nada, zilch, zip
Number of false-positives = sorry, lost count
Number of years the “WIMP” hunt can continue = unlimited?
Notice that the most natural and promising candidate for the galactic dark matter, stellar-mass primordial black holes, is almost always missing from the discussion.
Do you ever feel like theoretical physicists are treating you like mushrooms - keeping you in the dark and feeding you bullsh*t so they can continue their lucrative "find the wimp" game indefinitely?
Robert L. Oldershaw
http://www3.amherst.edu/~rloldershaw
Discrete Scale Relativity
I had missed the connection between dark matter and Alzheimer's, but you may be on to something there...
Reply | Report Abuse | Link to thisI love this search. Okay start with you are looking for an energy force that interacts with gravity and not with the other 3 know forces. Now add that what gives any visible matter is the interaction of electron clouds which are energy but how do I say, made up of nothing except for the smallest of small electrons which occupy shells because of quantum rules and established science.
Reply | Report Abuse | Link to thisSo what gives matter volume in our little view of the 2 to 4% visible universe. The answer is the force EM... So what if not interfacing with EM the dark matter does not occupy volume in our resolution of the universe. So we can search for ever, but if something doesn't occupy space but does react with gravity. What do you expect to see? We can only see in the EM field. Right?
Here is an idea suppose both dark matter, and energy is indirect proof that we live in a multiverse and maybe with branes.
Reply | Report Abuse | Link to thisDark matter could just be other brane's gravity leaking into ours (some of them may have much larger values of gravity). Dark energy could be Parallel Universes effects on pulling our universe from out side or effects of other very distance big bangs with in our brane. Just put it out there for you to rip apart (have fun). Don't you just love the String theory. Personally I have trouble believing all that is, is just energy strings shake rattle and rolling on a brane.
Just to point out that the presence of dark matter has only been inferred for very large scale objects, or rather aggregations of hundreds of billions of massive objects. The effects of gravitation at smaller scales, in simpler configurations, within galaxies or the Solar system, for example, do not seem to indicate any conflict with the established methods of approximating gravitational effects or the gravitational constant.
Reply | Report Abuse | Link to thisThis is why dark matter's existence is only inferred for large scale configurations of massive objects - halos enveloping galaxies, for example. This is also why some have provided modified gravitational theories that presume increased gravitational effects for large scale objects.
Alternatively, the standard methods developed for convenient approximation of gravitational effects within relatively small scale configurations of objects may not directly apply to such vast distributions of many billions of massive objects.
In this last case, gravitational effects are not different at large scales and there is no large scale missing mass: complex distributions of interacting masses require more sophisticated (and difficult) methods of estimating both their masses and the effects of their complex gravitational interactions. Please see my initial comment #1 for additional information.
Why do people like even bother to comment on this website?
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Reply | Report Abuse | Link to thisDr.Clara Moskowitz & SPACE.com, please comment and issue the necessary correction in your Article extract -
"Dark matter is an elusive substance that is invisible and almost never detected, except by its gravitational pull." ( Should read as below)
Dark Matter is an elusive substance that is invisible and almost never detected,except by its "ANTI-GRAVITATIONAL PULL"
That's the first I've heard of it - can you provide references, or at least some further explanation? Otherwise I'm afraid it's you who should issue a correction.
Reply | Report Abuse | Link to thisSometimes, pop science articles (like this one) bug the hell out of me.
Reply | Report Abuse | Link to thisI recently watched the History Channel series "The Universe" wherein it was said that dark matter makes up 75% of the Universe (that would be "THREE quarters" in fractions) but this article starts out saying that dark matter "may make up ONE quarter of the Universe." Where's THE CREDIBILITY in pop science??!!
The only thing we know about dark matter now is that it (OR SOMETHING) produces gravitational effects (like "lensing" of light cast by objects behind or near the border of a "dark matter region.)" That's about as tenuous as it gets when it comes to detection.
What about gravitons? But they've not been detected or proven to exist either. What about inter-dimensional mechanics? Can't something in another dimension affect things in other dimensions? Yeah - but how did 8 of the 11 (theoretical) dimensions get rolled up into impossibly tiny "strings?" No one knows and, so far, there's no indication that any research method is actually getting close to detecting/proving any of th is stuff.
A lot of this is interesting theory and hypothosis, but when pop sci writers are let loose on it - it becomes nonsense and therefor annoying.
I kind of agree with you, especially about the definitive proclamations made in TV programs - it seems scientists know everything already!
Reply | Report Abuse | Link to thisTo clarify a bit, though, dark matter (WIMPS) is often considered to contribute around 23% of the total mass-energy of the universe, while 'ordinary' baryonic matter (atoms) contributes about 4.6%, while dark energy is thought to contribute the remaining 72% of mass-energy. See
http://en.wikipedia.org/wiki/Dark_matter#Overview
From those proportions, matter is thought to contribute a sum of about 28% of the total mass-energy in the universe, so dark matter should represent 83% of the matter in the universe (in terms of mass-energy). I think this is where the 75% figure you mentioned came from, as these figures have varied over the past several years...
As I explained in my initial comment #1, I have reason to be skeptical that any dark matter is necessary to explain the rotational characteristics of galaxies if established gravitational theories are properly applied to the actual mass distributions of of galaxies. I think this was the primary justification for the cosmological dark matter estimates, although this is difficult to nail down.
As you mention, weak gravitational lensing is often cited as the best evidence for the presence of dark matter. However, in these instances it's presence is inferred from extremely complex analyses. As I understand, typically for galaxy clusters, astronomers first statistically determine the minute optical distortions imparted to literally thousands of background galaxies. They then typically estimate the total mass contained within the galaxy cluster (comprised of up to hundreds of galaxies and even more massive gaseous intracluster medium) by analyzing the motions of galaxies within it. They then determine the total mass necessary to produce the derived optical lensing affects - if this exceeds the total estimated galaxy mass then the difference must be additional dark matter. I'm not an astronomer, so I can only hope that I've reasonably characterized to process to give you some idea of its complexity and potential for error. I also think that the inracluster medium may contribute some significant amount of ordinary optical lensing effects not usually accounted for, but I don't have proof of this...
(continued)
Reply | Report Abuse | Link to thisPersonally, I suspect the biggest problem with most TV programs like "The Universe" series is that their target audience seems to be children, so they often illustrate the subject with simplistic analogs & demonstrations (Wow! - Big explosions!) and present their information as if all scientists agree with the consensus perspectives presented. Not to mention the pan and zoom editing of interviews the same group of professional talking-head physicist-actors reading a script seemingly targeted to children with attention deficit disorder. But that's just my opinion...
How correct is the suspicion that Big Pharma & other corporate tentacles really don't want a cure for anything. They'll buy out a scientist that invents a new cure then stash it away, never to see the light of day for fear of killing off the money train that hope/guilt fuel - not unlike the underground vaults of diamonds kept from the public to keep diamond prices artificially inflated.
Reply | Report Abuse | Link to thisAt least with this WIMP science, it's an open ended venture. I'd rather support this sort of science than toss my $$ into the black hole of cures for disease.
If i'm incorrect, show me the last real CURE they've come up with...and i don't mean a drug with 20 potential side effects (that are meant to keep you coming back for life).
Polio. I grew up in the 1950s going to school with kids crippled from polio. I think they might not have lasted long.
Reply | Report Abuse | Link to thisHowever, there's an unsubstantiated report that HIV & AIDs are the products of at least one drug company's use of chimpanzee tissue to produce oral polio vaccines in cheap, uncontrolled facilities for large population tests in Africa during the early 1960s - that just might count against them, if true!
The conclusions of theoretical astrophysics that the additional gravitational force in the Universe exists and it is due to an existence of Dark Matter are in contrary to experiments being conducted by European Laboratory for Particle Physics in Cern.
Reply | Report Abuse | Link to thisResearchers at CERN announced on September 23, 2011 and confirmed again on 19 Nov 2011 that neutrinos traveled through the Earth's crust faster than the light. Lastly, they confirmed just the speed of light for these neutrinos.
Neutrinos propagate as traveling matter. From this view, the regular speed of neutrinos, so their speed in a vacuum, should only reach the speed of light since photons propagate as traveling energy. Physicists say neutrinos have mass. According to the special theory of relativity, any object having mass never can reach the speed of electromagnetic waves. Then finding that the speed of neutrinos traveling through a medium is equal to the speed of light (at least) in a vacuum confirms that neutrinos speed up. They had to accelerate at some spot from Cern to Gran Saso in Italy. If an object having mass accelerates then a force is present per Newton’s second law. It states that acceleration of an object dependents directly upon the net force acting upon the object, and inversely upon the mass of the object; a (acceleration) = F (force)/ m (mass). Therefore, findings accelerating neutrinos declares the finding of the new force related to the matter. Concluding is that last experiments measuring the speed of neutrinos registered another force for matter.
The discovery of the new force acting upon neutrinos according to Newton consequently determines another force, which is equal but oppositely. If for every action, there is an equal and opposite re-action”, then when the mater between Cern and Gran Saso exerted a force onto neutrinos consequently neutrinos also exert an equal and opposite force on the matter through which neutrinos traveled. Anyway, neutrinos inducted this force in the matter during their contact with the matter. Since neutrinos must have their origin, this inductive force pulls the matter to the source of neutrinos. That is why we should calculate also inductive attraction besides the gravitational attraction in the universe.
More information are in the book: "Attraction and Repulsion in the Universe" where the Mass, the Dark Energy and the Dark Matter are explained.
http://outskirtspress.com/attraction_repulsion/
The mass of a neutrino has yet to be accurately measured, but is now thought to range from 0.2-2.2 eV. For comparison, the electron's mass is 0.511 _million_ eV. While their mass is non-zero, it is so close to zero that, for distances as small as the Earth's diameter, they effectively propagate at the speed of light.
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Neutrino#Mass
Neutrinos are electrically neutral, so only interact with other particles very weakly and can pass through the entire Earth without every contacting any other particle. In contrast, photons traversing even a transparent medium are also not slowed except for their continual interactions with the medium's atoms, through their absorption and re-emission by charged particles. For example, the effective speed of light in water is about 3/4 of its speed in vacuum, even though photon propagation speed between particles is the same as it is in a vacuum.
In comparison, the effective speed of neutrinos in water remains very near the speed of light in a vacuum. As I understand, no external accelerating force is necessary for neutrinos to pass through the Earth's diameter at effectively the speed of light in a vacuum.
"I think we're looking in enough different ways that unless it's something that we just haven't thought of at all yet, it seems to me we're very likely to find it within the next decade,"
Reply | Report Abuse | Link to thisYes, indeed, Dr Bauer, it's something that we just haven't THOUGHT OF AT ALL YET! In that regard, however, we did discover something spectacular not that long ago but complacently ignored its possible ramifications to a good part of fundamental physics here. In 2005, Nature carried a finding that didn't seem to get the full attention and scrutiny it warranted. Without further ado and for that Nature article and it's straightforward implications here to our current ad hoc theory for dark mmatter, let me kindly refer you to the self-explanatory website: http://www.sittampalam.net/TheSuperwind.htm
It's as elementary as action-and-reaction and cause-and effect, without the need for recourse to exotic particles, such as WIMPS and whatnots, leave alone the human resource and the billions of dollars in cost.
Thank you all, and Cheers!
www.toe.tv
Dr. Randy Mills believes that dark matter is made of Hydrinos. Hydrinos are hydrogen atoms that are smaller than normal hydrogen atoms (see http://www.youtube.com/watch?v=OHihXCVUNUY) Dr. Mills believes and predict certain frequencies of emissions of these hydrinos that science calls "unknown". Also see www.blacklightpower.com.
Reply | Report Abuse | Link to thisYour link begins with a nice history of how Vera Rubin (et al.) established the requirement for dark matter to explain why spiral galaxies do not rotate like planetary systems. There is no need to go further to understand the source of the problem...
Reply | Report Abuse | Link to thisThe problem is that this expectation is based on a misconception. Why do the rotational velocities of planets diminish as a function of their radial distance from the Sun? Very simply, because the Sun's mass is the physical source of the Solar system's gravitational energy! The Sun contains 99.86% of all mass within the Solar system - that enormous mass dominates all gravitational interactions.
Why do the rotational velocities of the hundreds of billions of objects within spiral galaxies not diminish as a function of their redial distance? Because they are not each gravitationally bound to only a central mass - each discrete object is gravitationally bound to all others. Almost no matter what distance from the galactic center an object is, it is primarily bound to all other objects - preferentially to the objects nearest to it.
Objects at the periphery of a spiral galaxy disk are not expelled by their rotational momentum because they are not just bound to the distant galactic center - they are more strongly bound to billions of surrounding objects.
There is no further need to explain why spiral galaxies do not rotate like planetary systems; no need for compensatory galactic dark matter. Please see my comment #1 for additional reference information.